CN1275923A

CN1275923A - Filter material construction and method

Info

Publication number: CN1275923A
Application number: CN 97182458
Authority: CN
Inventors: B·卡劳格; D·J·迪德雷
Original assignee: Donaldson Co Inc
Current assignee: Donaldson Co Inc
Priority date: 1997-09-29
Filing date: 1997-09-29
Publication date: 2000-12-06
Anticipated expiration: 2017-09-29
Also published as: CN1134280C

Abstract

A preferred filter media is provided. The media includes a fine fiber web secured to the surface of a coarse fiber support. A preferred filter media, comprising multiple layers of fine fiber media separated by coarse fiber support is provided. Advantageous filter constructions result and are provided. Also according to the disclosure, methods for using such arrangements to filter are provided.

Description

Structure of filter material and preparation method thereof

FIELD OF THE INVENTION

The present invention relates to filter, filtration device structure, be used for the material of filtration device structure and the method for filtration.Application of the present invention relates in particular to from fluid filtered particles from air stream for example.Technology as described herein relates in particular to the advantage of utilizing this row to put, and it is to contain one or more layers fine fibre at filter media that this row puts.

The background of invention

The fluid for example inside of air and air-flow usually carries particulate material.Under many occasions, require from fluid, to remove part or all of particulate material.For example, enter motor vehicle cabin, motor car engine or produce the interior air stream of powered device, directly enter the air-flow and the air stream that enters various combustion furnaces of gas turbine, particulate material is usually contained in its inside.Use under the air cleaner situation in the cabin,, need remove particulate material for to passenger's comfortableness and/or consideration attractive in appearance.About entering air and the air-flow in engine, gas turbine and the combustion furnace, also need to remove particulate material wherein, because in fact they can hinder the inherence work of related various mechanisms.

Under other occasion, also can comprise particulate material by industrial process or engine gas interior that produce or that discharge.Can maybe should discharge at such gas, and/or before being discharged in the atmosphere, also require from these air-flows, to remove substantially particulate material through various outlet devices.

Row's mode of putting of having developed many fluid filters is used for removing particulate material.Owing to there being conspicuous reason from the following describes, requiring to improve the row who is used for this purpose and put.

Can be by considering following media type, i.e. surface load medium and deep layer medium are understood the part basic principle and the problem of design air filter.Every kind of media type is all furtherd investigate, and they all are widely used.Some principle relevant with them for example having announcement in the U.S. Patent No. 5,082,476,5,238,474 and 5,364,456.The whole contents of introducing these three patents here for your guidance.

In a word, for any given application, the design of filter generally all is related to the high efficiency that reaches filter and the characteristic that designs and for reaching the compromise selection of the characteristic that top load amount (being the long life of filter) designs.The useful life of filter generally falls to determine according to the selected limiting pressure of passing through filter.That is,, when having reached the limit value of this application or design by the formed pressure of filter, generally just think that filter has reached its time limit that can rationally use for any given application.Because it is the formation of pressure is the result of load,, relevant than the load capacity that long useful life is general direct with higher for the system that efficient equates.

Efficient is the tendency that capture medium particle and not making it passes through.Usually, the efficient of filter media that removes particle from air-flow is high more, and generally speaking, just fast more (variable of supposing other keeps constant) falls in the pressure that filter media ground reaches " useful life ", and this should be conspicuous.

The paper filter element is widely used surface load form of medium.Generally speaking, the paper element contains the densification pad of cellulose fibre, and cellulose fibre becomes vertical orientated with the airflow direction that carries particulate material.Paper is made generally in to can permeating airflow, also has enough thin pore-size and suitable porosity stops the particle greater than a certain selected size to pass through.When air-flow process filter paper, the particle of the entrance side of filter paper by spreading and damming and from air-flow, catch and retain selected size.Particle is collected in the entrance side of the filter paper form with the dust filter cake.The dust filter cake has also begun the effect of filter simultaneously, raises the efficiency.Sometimes this is called " timeliness ", and promptly efficient becomes and is higher than efficient originally.

A for example above-mentioned simple filtering device design runs into two class problems to I haven't seen you for ages.The first, better simply fault, promptly breaking of paper can be caused the damage of system.The second, when the entrance side of particulate material at filter accumulates fast, when becoming thin dust filter cake or layer, it in fact finally can stop up or close the fluid passage in the filter.Therefore, filter clogging effect although it is so is higher relatively, but their useful life is not long usually, puts when they needing to be used for the row by a large amount of fluids, when having a large amount of sizes to be equal to or greater than the particulate material of " a certain selected size " in the fluid, especially like this.Here " a certain selected size " refers to be filtered that device effectively dams or the particle size collected or bigger size.

Adopted many methods to improve for example " useful life " of paper filter of surface load filter system.A kind of method provides the medium of foldable structure, and with respect to smooth non-foldable structure, it makes the media table area in the face of air-flow obtain increasing.Can improve the useful life of filter although it is so, but it still is restricted substantially.For this reason, the medium of surface load is mainly used in by the lower occasion of the speed of filter media, is not higher than about 20-30 feet per minute clock usually, typically is about 10 feet per minute clocks or following." speed " speech here is the average speed (volume that promptly flows through is divided by media area) by medium.

Generally speaking, the speed of crossing the fan-fold paper medium when air communication increases, the filter useful life will with square the shortening pro rata of speed.Therefore, when the fan-fold paper filter system of surface load was used as the certain filter of the system that needs the circulation mass flow air, filter media just needed bigger surface area.For example, the typical cylindrical shape fan-fold paper filter cell of the diesel truck on highway that travels, the about 9-15 inch of diameter is about the 12-24 inch, the about deeply 1-2 inch of fold.Therefore, the filter table area of medium (simultaneously) typically is the 37-275 foot ²

In many application, especially the higher occasion of fluid velocity uses another kind to be sometimes referred to as the filter media of " deep layer " medium.Typical deep layer medium contains the thicker fibrous material of entwining.The deep layer medium defines according to the percentage of its porosity, density or solids content usually.For example the solid state medium of 2-3% can be a fiber mat deep layer medium, and about 2-3% that its row is changed to cumulative volume is fibrous material (solid), and all the other are the air or the gas compartment.

The useful parameter of another kind of definition deep layer medium is a fibre diameter.If it is constant that the percentage of solids content keeps, and fibre diameter (size) reduces, the size in hole just reduces; That is, it is more effective that filter becomes, and can more effectively catch littler particle.

The density that typical conventional deep layer medium filter is a deep layer constant relatively (or uniformly) medium promptly is solids content constant system of basic maintenance on its whole thickness of deep layer medium.Here " substantially constant " also only is less fluctuation even if refer to find that on the entire depth of medium density has fluctuation.Such fluctuation for example can originate from the mild compression of the outer surface in the use, and the container that it is put into wherein by filter media produces.

The row who has developed density gradient moldeed depth layer medium puts, and for example United States Patent (USP) 4,082, and 476,5,238,474 and 5,364,456 have disclosed some such rows puts.In a word, the row of deep layer medium puts and can be designed to can " carry " particulate material basically on its whole volume or the degree of depth.Thus, prescribe a time limit when the entire service life that reaches filter, compare with the surface load system, such row puts and can be designed to carry more particulate material.Yet, generally speaking, put big load effectively owing to will weigh this row, so just need the lower medium of solids content.Density gradient type system, for example above-mentioned patent is mentioned, and has been designed to provide high efficiency and than long life.Under some occasions, " light " (polish, the i.e. decorative layer) filter during the surface load medium is put as this row.

The general introduction of invention

According to some aspects of the present invention, provide the structure of filter media.This filter media structure can be used as filter media in preferred filter row puts.For example under some occasions, one deck medium during it can be put as multilayer row.In some rows put, filter media layer of the present invention can pile up, and formed preferred construction.Sometimes, various dielectric layers or volume here is called " district ".

Preferred filter media structure of the present invention comprises the permeable crude fibre medium of the ground floor with first surface.The ground floor fine fiber media is fixed on the first surface of the permeable crude fibre medium of ground floor.The permeable crude fibre material of ground floor preferably contains at least 10 microns of average diameters, typically and preferably is about the fiber of 12 (or 14)-30 micron.The permeable crude fibre material of ground floor also preferably has and is not higher than about 50 gram/rice ²Unit Weight, preferably about 0.50-25 gram/rice ², at least 8 gram/rice most preferably ²The permeable crude fibre medium of ground floor preferably at least 0.0005 inch (12 microns) is thick, and it is thick typically and preferably to be about 0.001-0.010 inch (25-254 micron).

In preferred row puts, the permeable crude fibre material of ground floor contains such material, if separate and adopt the Frazier permeability test method to estimate from remaining structure, it shows at least 150 meters/minutes permeability, typically and preferably about 200-450 rice/minute.It also is preferably such material, if estimate alone, it has and is not higher than 10% efficient, preferably is not higher than 5%.Typically, it is the material that efficient is about 1-4%.Here, when mentioning efficient, except as otherwise noted, it refers to according to ASTM#1215-89 described, with the efficient of 0.78 μ monodisperse polystyrene spherical particle measurement under 20 feet per minute clocks (6.1 meters/minute).Here it is sometimes referred to as " LEFS efficient ".

Here, when one deck is used for the material that row of the present invention puts, " have " or " alone " can show or it " separates " performance that is shown when testing when characterizing from remaining structure with regard to it, mean that the raw material with regard to making it characterizes.Just, if for example mention " slightly " layer material in the compound, the above-mentioned explanation of mentioning is material and the performance that just exists before the structure about entering.In the upper and lower literary composition relation of this paper, there is no need to relate to the concrete property numerical value or the performance numerical value of layer when running in the composite construction.

Be fixed in the fine fibre material layer of the first surface of permeable crude fibre dielectric layer, one deck fine fiber media preferably, wherein the average diameter of fiber is no more than about 10 microns, usually and preferably be no more than about 8 microns, typical case and preferred fibre diameter are less than 5 microns, and be big in the scope of 0.1-3.0 micron.Be fixed in the ground floor fine fibre material of the permeable crude fibre material of ground floor first surface, also preferably have and be no more than about 30 microns gross thickness, more preferably no more than 20 microns, be most preferably not exceeding 10 microns, this gross thickness typical case and preferably be about the layer 1-8 of interior fine fibre average diameter times (more preferably no more than 5 times).

When being applied to air filtration, air filtration and HVAC in the suction system of engine, gas turbine, the cabin (heat, heating ventilation and air-conditioning) system for example, the upper limit of preferred fine fiber layer Unit Weight is as described below: for the fibrous material average-size is 5.1 microns glass fiber material layer, is about 35.8 gram/rice ²For the fiber average-size is 0.4 micron glass fiber material, is about 0.76 gram/rice ²Glass fibre with for average-size being 0.15 micron is about 0.14 gram/rice ²For average-size is 5.1 microns polymeric fine fibers, is about 17.9 gram/rice ²For average-size is 0.4 micron polymer fiber, is about 0.3 gram/rice ²For average-size is 0.15 micron polymeric fine fibers, is about 0.07 gram/rice ²In a word, for this kind application, the Unit Weight of the superiors' fine fibre preferably is no more than about 1 gram/rice ²

When material is applied to require high efficiency occasion, for example be applied to select room air, select liquid (for example lubricating oil, hydraulic fluid, fuel filter system or smoke collector), generally speaking, the preferred upper limit of fine fiber layer Unit Weight is as described below: for average-size is 2.0 microns glass fibre, is about 15.9 gram/rice ²For average-size is 0.4 micron glass fibre, is about 1.55 gram/rice ²With the glass fibre that is 0.15 micron, be 0.14 gram/rice for average-size ²For average-size is 2.0 microns polymeric fine fibers, is about 8.0 gram/rice ²For average-size is 0.4 micron polymer fiber, is about 0.78 gram/rice ²For average-size is 0.15 micron polymer fiber, is about 0.19 gram/rice ²In a word, for this application, the Unit Weight of the superiors' fine fibre preferably is no more than about 1 gram/rice ²

Be applied to the airfiltering given upper limit, for example suck the system of air etc., decide according to the 50%LEFS efficient of fine fiber layer thickness that is about 5 times of fibre diameters and layer.For requiring high efficiency occasion, this assumed value is decided according to the thickness of 5 times of fine fibres and about 90%LEFS efficient of every layer.

In a word, for any given occasion, preferred Unit Weight depends on such variable, for example: related application requirements (for example will be caught corase particles or fine particle in operation, or both, need the high efficiency still inefficient), desired useful life, selected fibrous material and employed fiber size.Generally speaking, (for example be about 90%LEFS) when requiring individual layer efficient higher, glass fibre will be worked usually well, and system will have bigger Unit Weight (for example about 20 gram/rice ²) and bigger fibre diameter (for example 2-3 micron).

On the other hand, when the efficient that requires individual layer is lower, and when still having higher useful life (results that use many layers to produce) after the load,, use lower efficient (for example about 10%LEFS) for any given layer.This will comprise lower Unit Weight and the little fiber of equal diameters.Can applying unit weight be about 0.005 gram/rice in this case ², fiber size is about 0.2 micron polymer fiber (though also can use glass fibre).Here, give regularly when Unit Weight, the density default of glass fibre is 2.6 gram per centimeters ³, the density default of polymer fiber is 1.3 gram per centimeters ³

In a word, provide longer useful life, use more layer so usually, and every layer efficient is all lower if the engineer is needed.If the engineer needs very high filter clogging effect, and long life is optional, so generally speaking, use the less layer with higher LEFS efficient.

Here, " first " or " second " word about structure example such as dielectric surface is not meant any ad-hoc location in the medium.For example whether " first surface " speech itself does not represent related surface in other surperficial front or back, or be positioned at the top of other surfaces or below, but be used to provide clearly reference and aforesaid basis." average diameter of 1-8 fine fibre " speech is meant and is about the fine fibre average diameter 1-8 degree of depth or thickness doubly in the related fine fiber layer.

In typical preferred system, the ground floor fine fibre of fine fiber media contains such fiber, its diameter be no more than fibre diameter in the permeable crude fibre medium of ground floor about 1/6, preferably be no more than about 1/10, under some occasions, preferably be no more than about 1/20.

For some application, the fine fibre material preferably makes like this and row puts for ground floor (in the operation anterior layer): offer formed compound with at least 8%, preferred at least 10%, typically be 20-60%, most preferably at least 30% and be no more than total LEFS efficient of about 70%.Then, such compound can pile up and form effectively for example greater than 97%, if desired can be up to 99% or higher filter.They also can be used for the low but very long filter of useful life of efficient, and typically at least 10%, the efficient of 50-97% for example.Fine fiber media also preferably makes like this and row puts for ground floor (the anterior layer in the operation): make total permeability of formed compound (being the composition of permeable fiber medium of ground floor and the ground floor fine fiber media above it) be at least 20 meters/minute, typically and preferably be about 30-350 rice/minute.

Here, " the anterior layer " relevant with fine fiber layer or " outermost layer " word refer to that position in use is in the fine fibre material layer (average fibre diameter is less than 8 microns) of anterior layer with respect to other fine fiber layer.May be in addition than the anterior layer fine fiber layer medium of anterior layer (non-fine fibre) layer more.

The permeable crude fibre material of ground floor can be the fiber that is selected from multiple material, for example comprises polymer fiber such as polypropylene, polyethylene, polyester, polyamide or polyvinyl chloride fibre and glass fibre.

According to some aspect of the present invention, filtration device structure can be provided, it comprises above, the preferred at least 3 layers of fine fibre material of one deck.This row puts and typically comprises three layers or above such layer.Fine fiber layer in the multilayer system needn't be mutually the same like this.Yet every layer of fine fiber layer is preferably above-mentioned for the layer in total description scope of ground floor fine fiber media in the described dielectric structure.In this row put, every layer of fine fibre material preferably separated with the permeable crude fibre material of one deck that its fine fibre material layer that one deck is adjacent down is used as wall or blank medium.

Permeable crude fibre material layer needn't be identical, but preferred every layer all is layer in total description scope of permeable crude fibre medium for ground floor of given relevant filter media structure.Preferably arrange at some and to put, as mentioned above, on two surfaces of anterior layer and final layer, total composite dielectric structure also comprises the permeable crude fibre medium of one deck.

If desired, the filtration device structure folding row that also can contain compound puts.For example this row puts can contain the dark fold of 0.25-12 inch (0.6-30.5 centimetre), and corrugation density is at least 1-15/inch (1-15/2.5 centimetres).When corrugation density is at least 15/inches, and row to put be with cylindric shaping, when fold extended longitudinally, this density referred to the fold spacing along internal diameter or inner surface.

According to of the present invention some preferably arrange and put, they comprise defined medium in the total filter structure usually.Preferably arrange for some of this application and to put, contain the medium of putting with folded configuration row cylindraceous, its fold longitudinally promptly stretches with the same direction of the y direction of drum usually.Put for this row, identical with the conventional filtration device, medium can be embedded in the end cap.For typical conventional purposes, if desired, this row puts and can comprise anterior layer lining and back layer lining.This structure can be for example according to U.S. Patent application No.08/426, and 220 described rows put, with seal in the deep layer medium or the outsourcing front cover with using, this patent is here introduced for your guidance.

Can predict, in some applications, medium of the present invention can together use with the medium of other types, and conventional media for example is to improve total strainability or useful life.Medium for example of the present invention can be stacked to, or is applied on the conventional media in other mode, and the row that can be used for piling up puts, or pack into (global feature) comprises in the structure of one or several regional conventional media.It can obtain good load performance as the anterior layer of this medium; And/or it can be as the back layer of conventional media, as high efficiency bright filter.From more detailed description below, can obviously understand many possible variations.

Some row of the present invention puts also and can be used for the liquid filter system, and particulate material promptly wherein to be filtered is held under the arm and is wrapped in the liquid.Some row of the present invention puts also and can be used for smoke collector, and the row who for example filters mist from air puts.

According to the present invention, also provide filter method.This method generally includes utilizes the advantage of above-mentioned medium to filter.The same as what can find out from following explanation and embodiment, medium of the present invention can be made given shape, to provide than the advantage than long life in the effective system.

Apparent from above-mentioned discussion and following detailed description, can provide some specific preferred row to put, especially air filter arrangement is preferably arranged and put.Their form is a feature with the filter media structure.Preferred filter media structure comprises the layers of fine fiber dielectric layer, and promptly two-layer at least, every layer of fine fiber media all contains diameter and be no more than about 8 microns fiber.The fine fiber media layer of multilayer comprises an outermost layer.Again, in the context relation here, " outermost layer " refers to one deck fine fibre in medium, when medium is organized as filter media or is directed, this layer be positioned at any other fine fibre material layer above.This first " outermost " layer that does not mean that the fine fibre material is the outermost layer of structure medium.But " outermost layer " in the layers of fine fiber layer or end layer.Then, when using this filter media structure, this fine fiber layer will be the top fine fiber layer of structure medium.This outermost layer fine fibre preferably contains average diameter and is no more than 5 times the fiber that about 5 microns, thickness are no more than fine fibre average diameter in the outermost layer.Therefore, its maximum ga(u)ge will be no more than about 25 microns, and in typical application, use diameter less than 5 microns fiber, and its thickness is in fact littler.This outermost layer fine fiber layer preferably has moderate permeability, and himself is at least 90 meters/minute to the permeability of air.Certainly, if the permeability of this fine fiber layer together with the coarse carrier substrate measurement, if the permeability of total composition is at least 90 meters/minute, the fine fiber layer self performance also must reach above-mentioned requirements so.

Preferably has the permeable crude fibre dielectric layer between every pair of fine fiber media layer in this structure.Every layer of permeable crude fibre medium preferably contains the fiber of at least 10 microns of diameters, and if separate in the self-structure and estimate, so for the 0.78 μ particle that is limited, it is about 20% that every layer efficient preferably is no more than, more preferably no more than 10%.

This dielectric structure preferably comprises at least three layers of fine fibre material, though the following two-layer at least average diameter that needn't require except " outermost layer " is less than 5 microns, but more preferably they are at least less than 8 microns, their permeability can be than outermost layer fine fibre material little, every layer of self permeability is preferably at least 45 meters/minutes.

In addition, preferred filters dielectric structure of the present invention also can be defined as and comprise permeable crude fibre medium of ground floor and ground floor fine fiber media position first surface thereon, this crude fibre medium contains the crude fibre of at least 10 microns of average diameters, for 0.78 μ particle, its efficient is no more than about 5%.Ground floor fine fibre material preferably contains average diameter and is no more than 5 times the fiber that about 5 microns, thickness are no more than fine fibre average diameter in this ground floor approximately.The permeability of this material self is preferably at least about 90 meters/minute.Certainly, this dielectric structure can be used in combination with other fine fiber layer and crude fibre material, even can be used for adopting the total media structure of other media types, and for example the deep layer medium with paper or glass medium or other types is used in combination.The dielectric structure of this embodiment also can comprise the fine fibre material of many more deep layers, and every layer is all separated by one deck crude fibre medium with adjacent layer.

In some cases, can handle fiber, to strengthen such characteristic, for example efficient, filter useful life or both.

Adopt medium of the present invention, the total filter structure can be provided, being described in detail one of in above-mentioned two kinds of preferred implementations.

Brief description of drawings

Fig. 1 is the section schematic illustration of the individual layer fine fibre filter media of theory.

Fig. 2 is the section schematic illustration of the individual layer crude fibre filter media of theory.

Fig. 3 is the section schematic illustration of the individual layer fine fibre filter media of theory; The medium of Fig. 3 is with shown in Figure 1 different.

Fig. 4 is the section schematic illustration that theoretical individual layer crude fibre medium row puts, and the percent solids that this row puts is put identical with row shown in Figure 3.

Fig. 5 is the plan view of the part on dielectric structure of the present invention surface.

Fig. 6 is the generalized section of medium shown in Figure 5.

Fig. 7 is the cut-away section schematic diagram of multilayer dielectric structure of the present invention.

Fig. 8 A is that the folded medium that comprises dielectric structure of the present invention is arranged the part perspective view of putting.

Fig. 8 B is the amplification profile schematic diagram of the part that row puts shown in Fig. 8 A.

Fig. 9 is the schematic diagram of medium of the present invention, and it is placed through on the mechanical support structure.

Figure 10 is that the filter that filter media structure of the present invention is housed is arranged the side view of putting.

Figure 11 is the enlarged diagram of the cut-away section that obtains along whole 11-11 line among Figure 10.

Figure 12 is the electron scanning micrograph of the polymer fiber medium of conventional air lay.

Figure 13 is the electron scanning micrograph of the fiberglass media of conventional air lay.

Figure 14 is the electron scanning micrograph of conventional two-phase medium.

Figure 15 is the electron scanning micrograph of conventional two-phase wet-laying glass medium same as shown in Figure 14, and Figure 15 is the photo of taking the photograph from the back side of medium shown in Figure 14 one side.

Figure 16 is the electron scanning micrograph of the medium of first embodiment of the invention.

Figure 17 is the electron scanning micrograph of the medium of second embodiment of the invention.

Figure 18 is the electron scanning micrograph of the medium of third embodiment of the invention.

Figure 19 is the electron scanning micrograph of the medium of four embodiment of the invention.

Figure 20 is the electron scanning micrograph of the medium of fifth embodiment of the invention.

Figure 21 is that the medium of Figure 19 is according to the electron scanning micrograph after the described sodium chloride load herein.

Figure 22 is the datagram of experiment 5.

Figure 23 is some datagram of experiment 6.

Figure 23 A is other datagrams of experiment 6.

Figure 24 is the electron scanning micrograph after the medium load sodium chloride of the present invention.

Figure 25 is the schematic diagram that is used for the salt work pallet (bench) of some customization of testing.

Detailed description of the invention

The filtration advantage of A fine fibre

Generally speaking, in the filter media structure, by adopting thin relatively fiber to replace crude fibre,, medium filters advantage in theory for providing some.Fig. 1 and 2 for example.Fig. 2 illustrative " individual layer " fine fiber media has fixing interfibrous distance D _x, the distance between its expression adjacent fiber surface.Fig. 2 is that explanation has identical D _x, and the schematic diagram of the individual layer that wherein fibre diameter is bigger 12 times than fibre diameter among Fig. 1 approximately.

Contrast Fig. 1 and 2, obviously, for the zone with fixing medium periphery, the interstitial space during the air during the row of Fig. 2 puts between the fiber or the total amount of interstitial space are put than the row of Fig. 1 undoubtedly is littler.Therefore, in the row of Fig. 2 puts, only have quite little volume and can be used to carry the particulate material of being caught by system.In addition, put with the row of Fig. 1 and to compare, air-flow be easier to by the row of Fig. 2 put interrupt because to open wide the surperficial percentage that makes it to pass through littler in order not interrupt air-flow.

Apparent from the contrast of Fig. 1 and 2, if interfibrous average distance (D _x) keep constant, and the fiber average-size descends, generally can form more be used for load the space and form higher air flow permeability.

The row who considers Fig. 3 and 4 puts now.Fig. 3 and 4 is used for the single layer fibre in two deep layer media of illustrative system, uses the fiber of different size in this two individual system, and that percent solids or density keep is constant.Observe figure repeatedly, it is that the row of Fig. 3 puts and compares that but row that percent solids equate less with fibre diameter puts, and should it is evident that, the row of containing big fiber puts, the row who is Fig. 4 puts, and has big open area potentially, makes filter clogging effect lower (but permeability is very high).

For the effect of utilizing less fibre diameter, carried out theoretical research, and can come quantificational expression by the Si Tuoke number and the parameter of damming.

Nondimensional Si Tuoke number (Stokes) is expressed from the next:

Si Tuoke number=d _p ²ρ _pV/9d _fμ wherein, d _f=fiber size (diameter), d _p=particle size (diameter), ρ _p=particle density, v=near the time speed, μ=fluid viscosity.

From following formula apparent (at least in theory), work as d _f(fiber size) reduces, and the Si Tuoke number increases (supposing that its dependent variable is constant).

In a word, the Si Tuoke number is the reflection of inertial impaction.It can be understood by such mode: consider such possibility, when air-flow break-in or turning around fiber, direction can be left air-flow (rather than along with air-flow is turned) and clash into fiber facing to the particle of fiber in the air-flow.Each variable shown in the following formula Si Tuoke number is from totally reflecting in logic, and the increase of particle momentum (from the density and/or the speed that increase) is can not walk around with air-flow with particle to flow around the fiber but leave air-flow and directly clash into the bigger possibility of fiber relevant.Following formula also shows, when fibre diameter more hour, this possibility is bigger, this to small part be because: when fibre diameter is littler, the degree that fiber interrupts air-flow is littler.When air-flow during in the fiber bent around, this just makes effective field of flow of air-flow more press close to fiber surface, and has increased such possibility: the momentum than the particle of low-momentum still can be enough to leave air-flow, the bump fiber.

The another kind of need considering about why some fine fibre system as filter in theory generally speaking than the more effective problem of crude fibre system, be to dam by the represented particle of the parameter of damming.The parameter of damming (R) can be expressed from the next:

R=d _p/ d _fD wherein _pAnd d _fDefinition as above.

Generally speaking, the parameter of damming does not rely on speed and momentum, and it is only relevant with the size of particle and fiber.Generally speaking, it is relevant with such possibility: particle (when air-flow during break-in, can be turned with air-flow around fiber surface) still can clash into fiber and be hunted down.Therefore, it is not directly related with such possibility: the momentum of particle can be taken it air-flow out of and bring fiber into, and whether particle still can clash into fiber in air-flow and would rather say so.In a word, because the degree that less fiber interrupts air-flow is littler, and break-in (off-straight) takes place pressing close to the fiber surface place in air-flow, and therefore, less fiber is compared with bigger fiber, can be relevant with higher efficient and bigger bump interception capacity.

In a word, in medium, use the advantage of fine fibre for more obvious than small-particle.Therefore, when the filter application requirements filtered the littler particle of small-particle, especially 10 microns or size (diameter), the advantage of fine fibre can be particularly useful.

B and the interior use of filter media some problems and the restriction relevant than fine fibre

Providing in the aforementioned part with respect to crude fibre selects the littler fiber of diameter to be used for obtainable theoretic advantage in the filter media.Yet in the deep layer medium, if simply with very thin promptly about 8 microns and following, typically 5 microns and following, especially be about the fiber of 0.2-3.0 micron, replaces the fiber more than thick promptly about 10 or 12 microns (diameters), also can go wrong.For example,, can more be difficult to processing (compared with coarse fiber structure), in use be easy to subside, form very low permeability by the structure that the fiber of the about 0.2-5 micron of size is made.Promptly in structure when only to comprise diameter be 5 microns or following fiber, for top load and big flow fluid by the structure that keeps in fact opening wide difficulty, because the typically anti-mechanical strength deficiency of subsiding of such medium.When medium subsided, the space between the fiber became less, although as the perhaps still effectively structure of filter, load is quite fast, and permeability is little.In fact, such system has almost become the surface load system in behavior, because formed the lower porosity and the shallow degree of depth in fact.

Can conceive structure so with it, wherein extremely thin fiber mixes (promptly tangling) nearly with crude fibre.Yet, make effective filter row and put, particularly adopt the routine techniques that forms the deep layer medium that contains the different-diameter composite fibre, when fibre diameter has a great difference, be not easy to realize.For example, consider the system of a theory, wherein the fine fibre diameter is coarse-fibred 1/20.If the filter media that filtered air need pass through contains the fine fibre of the crude fibre and 50% (weight) of 50% (weight), this system is exactly a system (or fine fibre length is with respect to crude fibre length) that has a large amount of fine fibres with respect to crude fibre so.It can be space or the less system of porosity between a fiber.It perhaps is more effective, but it still can at a good pace reach load.In a word, if coarse-fibred weight descends with respect to fine fibre, problem will sharply worsen so.If coarse-fibred weight increases with respect to fine fibre, relevant with fine fibre so and with dam and the inertial impaction advantages associated will be by compromise.

C fine fibre some in medium are conventional to be used

There is the routine of some fine fibres in medium to use.Especially Donaldson Company Inc., the assignee of the present invention of Minnesota State Bloomington are at its Ultra-Web ^Used the fine fibre technology in the product.These products comprise the cellulose media of surface load usually, and it has the net of a diameter less than 1 micron polymer microfibers on front surface.

Such medium typically is applied in the pulsed cleaning dust-collector.In operation, the cellulose media of thick surface load is not as having under the situation of fine fibre, and part works as the IT device of small-particle.When this situation took place, the weak effect of pulse cleaning was because some particles are hunted down in cellulose media inside.Yet when using fine-structure mesh, fine-structure mesh operation is usually collected the particle of surface load cellulose fibre front, when applying opposite pulse, helps the release of particle.

United States Patent (USP) 4,011,067 another kind of having described fine fibre is used, and here introduces for your guidance.

This with reference to profile in, fine fibre is applied on the base material of porous.

D effectively utilizes a kind of usual method of fine fiber media for filtering purpose in filtration device structure

Having developed a kind of fine fibre that utilizes in filter media is that diameter is about 8 or 10 microns or following, preferred 5 microns or the following and usual method of the about 0.1-3.0 micron of diameter (on average) typically.Generally speaking, the permeable more coarse-fibred base material of porous is as supporter, support base material or the wall of fine fiber media very.Then, material can be shaped in a preferred manner, obtains the long filter of effective useful life.

In preferred system, utilize the advantage of the layers of fine fiber medium that separates in the above described manner.When using the layers of fine fiber medium that separates in the above described manner, just can easily obtain high-time high efficiency filter system.

In Fig. 5, provide schematically illustrating of filter material of the present invention.With reference to Fig. 5, material 1 comprises crude fibre 2 and fine fibre 3.Yet when manufactured materials, material 1 is not that the fiber by different size mixes or the material of mat nearly.But: material 1 comprises one deck (having the degree of depth) crude fibre 2 usually, is applied with the outer surface of fine fibre 3 above at least one.Be that medium has a fine fiber webs at least one outer surface of coarse fiber structure.Then, the fine fibre in the fine fiber webs does not mix with the crude fibre base material or tangles.Here, the layer of crude fibre 2 is sometimes referred to as permeable crude fibre medium or material layer.It contains 3 base materials thereon of fine fibre.

The row of Fig. 5 put can regard as to the hedge beam between the spider netting twine similar a bit.(if suppose that also cobweb is positioned and depends on the side or the surface of hedge, this is similar the most appropriate so).Beam or crude fibre 2 provide the open surfaces area of porous, do not hinder air communication to cross open spaces in fact.Fine fibre 3 expressions are suspended in the open spaces or cross the net of this open spaces.Because it is in fact great majority are not interrupted by crude fibre 2 by the air-flow of this material, less with involving of crude fibre 2 in dam bump and inertial impaction.Yet extremely thin fiber 3 is the lines that pass across in the space that air-flow in fact will flow through.Therefore just obtained relevant inertial impaction and the fine fibre size of clashing into of damming on advantage.In the application of using the above fine fiber layer of one deck, the homologue of cobweb comprises many hedges that pile up each other, and wherein each all has cobweb on its one side.Whole effect is piling up for thin cobweb at interval just.

In a word, Fig. 6 is the fragmentary cross-sectional view of material for example shown in Figure 5.It is schematic that Fig. 6 is actually.It will be appreciated that generally speaking, Fig. 5 is the figure that has amplified widely with respect to Fig. 6, purpose is to understand details.

In Fig. 6, the layer ordinary representation of coarse-fibred deep layer medium is at 4 places, and very the layer of fine fibre is illustrated in 5 places.It will be appreciated that fine fibre 5 is applied on the surface 6 of crude fibre base material 4.

Generally speaking, for preferred structure, fine fiber layer will be shaped as individual layer approx, does not have the thickness much larger than about 1-8 times of fine fibre diameter.In a word, in any given position, its degree of depth all will be not more than about 10-15 micron, typically be not more than about 2-4 micron.

The degree of depth of thick Supporting Media 4 will change with system is different.The degree of depth of expressing thick medium 4 simply that schematically illustrates of Fig. 6 is compared with the degree of depth of the layer of fine fibre 5, generally speaking is bigger.

Yet, if especially use very unlimited fine fiber layer, so owing to sizable interstitial space or interfibrous spacing (being the spacing between the fine fibre) are provided, so the structure of Fig. 5 and 6 might be the filter of efficient relative deficiency.Promptly when fine fibre sparsely distributed, the air that keeps clear of fine fibre through interstitial space can not be filtered on sizable degree.

As mentioned above, according to the present invention, in preferred filtration device structure, for example the mode of for example piling up with multilayer of the material as shown in schematic diagram 5 is arranged.On the possibility of quilt through the particle hits in the air-flow of whole system, wherein every layer of all similar to Fig. 5 folded multilayer can illustrate thinner fiber 3 with the effective density meter of reality.By the crude fibre 2 of porous provide than the macrovoid space, can form sizable load volume, permeability and thus than long life.Therefore, can form such theory: but can make so not only very effective but also have a structure of long useful life as filter.Pointed as following experiment, this also can realize in practice.

Arranging the further favourable aspect of putting as shown in Figure 5 understands by this way: consider such compound effect to trapped particle in operation.Generally speaking, if the load particle after one period the row of inspection put, will show and mainly be hunted down and be fixed in particle on the single fine fibre, its form is independent small-particle or particle granule.Spacing between the fine fibre is enough big, makes and can not produce bridge joints a large amount of between fiber.Among this Figure 21 that is discussed below demonstration is arranged.Really, interfibrous space is enough big, makes that dendritic particle will rupture and fall into fine fiber layer when beginning to produce bridge joint.

This is very favorable.During the less but row that efficient is higher in interfibrous therein space puts, can or cross spacing between fiber and produce a large amount of particle bridge joints.This can the blocking filter medium the part gas channel, and reduce the permeability of filter greatly.This can increase the pressure differential by filter, and finally shortens the useful life of filter.Yet the interfibrous space in the layer is big, can reduce this possibility.

From further understanding the explanation, if the particle bridge joint begins to form, it can rupture and fall into this layer or this fact of material so, can not cause the problem of relevant efficient, because the application of material for example shown in Figure 5 is in being applied to typically to comprise that the row of the above filter media of one deck puts.

In this part, illustrate that some row of the present invention who comprises a folded medium puts.As will be explained in detail in other parts below, by additionally thick and fine fibre being applied on the structure, just can make a folded medium, rather than pass through the preform compound (or layer) of constitutional diagram 5 shown types.Usually should be identical to the influence of filtering at last.Yet a kind of or other technology type, or alternative technology can not relate to performance former of final structure thereby carry out preferred with regard to some.

The typical structure of E

Apparent from above-mentioned explanation, when when being used for filter and being shaped, the typical filter media structure of many present invention all comprises multilayer dielectricity, has two-layerly at least, contains effectively that thick framework supports or fine fibre or fine fiber webs at interval.The example that this row puts is called one sometimes here to be folded, as shown in Figure 7.

Generally speaking, stacked row puts and can be made by the identical dielectric composite of multilayer.In addition, can form gradient in stacked row puts, for example mode is to adopt slightly different composite in every layer, or when making layered composite applied layer aptly.Material in each layer for example can run through difference aspect the fine fibre population mean density of thick supporter open spaces.In addition or in addition, the fine fibre diameter of each interlayer also can be different.Certainly, row puts one or more layers that can comprise a kind of ad hoc structure, and can comprise one or more different structures one or more layers.

With reference to Fig. 7, shown the dielectric structure 10 that generally speaking comprises folded different filter media layers.Put for row shown in Figure 7, consider common air-flow by direction shown in the arrow 11.Structure 10 comprises one deck medium or the areas of dielectric 13 that contains thick supporter 14, has skim fine fibre 15 on the surface of thick supporter 14.In shown given row was put, layer 15 was on the upper surface of supporter 14.Be similar layer 17 below the layer 13, it contains thick supporter 18 and top fine fibre thin layer 19.Row puts 10 and also comprises and constituting and darker layer 20,21 and 22 similar with 17 of layer 13.Therefore, put for row shown in Figure 7, thick regional 25 of layer 22 is positioned at the bottom.

Put for shown given row, sparse layer of protectiveness crude fibre or dielectric layer 27 be positioned at uppermost fine fiber layer 15 above.

In a word, it will be appreciated that the 0.020-0.060 inch (0.05-0.15 centimetre) of only having an appointment of the general construction among Fig. 7 is thick, in some cases even thinner for some embodiment.Therefore, it is exaggerated in the drawings, becomes undue big.It comprises a folded fine fiber layer, and wherein every layer is all separated with adjacent fine fiber layer by thick wall or supporting layer or base material.On each face, promptly uppermost 27 and nethermost 25 thick sparse layer or dielectric layer that all has protectiveness.The given row of Fig. 7 is put and is demonstrated the fine fiber layer that has 5 separation, but also can use the number of plies of other quantity.Here again do not require fine fiber layer mutually the same, or different thick supporting layers is mutually the same.In the upper and lower relation here, " separation " is meant that in fact every layer of fine fibre do not separate supporter and tangle with crude fibre, but every layer of fine fibre is usually located on the surface of supporting construction.

1. thick supporter/spacer structure

The main effect of roughage provide framework, and fine fibre runs through this framework and extends in the filter media layer of the present invention.Another of roughage mainly acts on the interval that provides between stacking material interior fine fibre zone or the layer, makes the fine fiber layer that is spaced can not collapse to the structure of fine and close (promptly low permeability and lower load).Thick supporter/spacer structure does not typically provide the filtering function of any essence.Really, it is preferably unlimited and permeable material, makes it as the filtration of any essence.

Generally speaking, for typical application application for example as described herein, preferably compound overall (being formed multi-bed filter medium) is that flexible row puts, and it can be arranged with multiple geometry.In some rows put, preferably thick supporter contained flexible fibre structure, and it has enough mechanics integralities or the base substrate performance makes it can accomplish this point.Yet, in some rows put, should " base substrate " can by be used for the different component of the crude fibre material of fine fiber layer at interval and provide, perhaps it can be provided by total compound.This will be described below.

Can be summarized as follows with select some relevant prior parameters of flexible fiber construction for thick supporter:

A. preferably if possible, just select the material that percent solids is very low, permeability is very high, run through " interstitial space " in the space of fine fiber webs extension with raising.Preferable material is according to method of testing described here, catches 0.78 micro particles, is sometimes referred to as LEFS efficient, filter efficiency only have an appointment 10% or following, typically 5% or following, preferably have only 1-4%.Preferably, it is the material with mono-layer osmotic performance, and when being estimated by Frazier Perm Test, its mono-layer osmotic is at least 150 meters/minutes, typically at least about 200-450 rice/minute.

B. thick supporter/interval insulant should be enough thick, is spaced to guarantee fine fiber layer.Generally speaking, for some systems, the unsawn timber bed of material needn't be than realizing that this required at interval minimum thickness is thick.Be anticipated that the thickness about about 0.001 inch (25 microns) is enough far away.Be thick selected material of base material or technology, can than about 0.001 inch thick, for example about 0.010 inch (254 microns), the extra thickness any advantage relevant with the actual performance that stacked row as effective filter puts all do not have essential getting in touch.That is, especially in stacked row put, the thickness of about 0.001 inch (25 microns) just was enough to support fine fibre, and can provide unlimited volume for the load particle.In many systems, in fact thicker thickness can not make this performance be increased to any significant degree.Therefore, preferably arrange at some and to put, the thickness of separating every layer of crude fibre material of fine fiber layer all is no more than about 0.030 inch (760 microns).Illustrated in addition that the fine fiber layer of separation preferably was no more than about 0.03 inch (760 microns).Yet also allow to adopt thicker thickness, thereby make the range of choice of the material that can be used as thick layer wideer.In addition, thicker sparse layer or crude fibre layer can provide improved base substrate or mechanical strength.On the other hand, thicker layer can occupy unnecessary or undesirable space in some filtration device structures.

Though c. less demanding to the certain material of making thick buttress material, the such material of preferred usually selection, it is enough strong and tough and tensile, can bear the operation during making and processing, and can stand processing conditions.An advantage of structure of the present invention is, do not using under " charged " or " static electrification " fiber, just can be provided for the medium in many effective filter systems.Therefore, some preferred system of the present invention all adopts the fiber that does not apply electrostatic charge.The another one advantage is, can by the fibrous material that obtains easily for example polymer fiber thick supporter is provided.Therefore, can select the material that can buy to be used as thick supporter or sparse thing.

D. the material of making thick supporter should be that fine fibre can be easily and the material that applies up easily.

Though the selection of fine fibre size depends on the application-specific of structure at least in part, coarse-fibred diameter is not too important for the operation of preferred filters, as long as can obtain lowest performance described here.Usually, be anticipated that in typical case and preferred the application, coarse-fibred diameter is at least 6 times of fine fibre diameter, typically and preferably about 20-200 times.In the row that typical wherein fine fibre size is about the 0.2-3.0 micron put, predictably, roughage contained the fibrous material that average diameter is about the 10-40 micron, typically is 12 microns or bigger.Put for preferred row, roughage typically has 6.0-45.0 gram/rice ²Unit Weight.

Usually, the crude fibre layer can comprise the aggregate of short fiber or the continuous in fact fiber base material of mixture or nonwoven.In the context here, " continuously " speech refers to that aspect ratio is fully big, to being essentially infinitely great, and promptly at least 500 or above fiber.The wet-laying material can be used as the nonwoven supporter, yet, in some systems, also can use airlaid material.

It has been generally acknowledged that, the fiber that can buy can be used as thick supporter by sparse thing.A kind of so sparse thing is Reemay 2011, available from Indiana 37138, and the Reemay Co. of Old Hickory.Usually it contains the spunbond polyester of 0.7 ounce.

In addition, also can use Walpole, the spunbond polypropylene material of Veratec grade9408353 of Veratec available from Massachusetts 02081.

Thick supporting layer can contain the fibre blend of different materials, length and/or diameter.

2 fine fibre network or nets

Be anticipated that optional majority kind material is as the material that fine fiber webs or network are provided.General principle below using is selected.

A. it should be such material: can easily form selected fiber than minor diameter, be applied on the thick supporter, or form the net or the network of such fine fibre.

B. it should be enough strong, can and filter run duration in processing and keep normal material.

C. it should be the material that can easily be applied on the thick supporter.

So far, the label of having mentioned by assignee Donaldson Company preparation of the present invention and sale is Ultra-Web ^Some product.These products comprise the fine fiber webs that is applied on the cellulose surface medium.Be used for preparing these and be used for Ultra-Web ^The technology of the fine fiber webs of product is the business secret of Donaldson Company.Yet, be anticipated that, as described here, be applied on the thick support structure and be used for piling up similar technique and the net that row puts, comprise suitable and spendable application of the present invention.This will become obvious by the following examples.Yet, also can use other fiber and technology type effectively, for example melt-blown process.

Usually,, predictably, depend on selected given row and put for typical structure of the present invention, the fibre diameter that fine fiber fraction provides be 8 microns or below, typically be lower than 5.0 microns, preferably about 0.1-3.0 micron.Multiple filter material can both easily provide such diameter, comprises for example glass fibre, polypropylene fibre, PVC fiber and Fypro.

More generally, can use polyacrylonitrile, can use with Seran ^F-150 is available from the poly-vinylidene chloride (polyvinyladine chloride) of the Dow Chemicals of Michigan Midland.Also can use other suitable synthetic polymeric fibers, make very thin fiber, the copolymer that comprises polysulfones, SPSF, polyimides, poly-vinylidene fluoride (polyvinylidine fluoride), polyvinyl chloride, chliorinated polyvinyl chloride, Merlon, polyamide, aromatic polyamides, cellulose esters, aerolate, polystyrene, poly-butyryl ethene and these different polymer.

Fine fibre can be fixed on the thick supporter in many ways.Used technology can be partly according to being used for making the technology of fine fibre or net and forming fine fibre and coarse-fibred material (one or more) is decided.For example, fine fibre can be by a kind of adhesive to thick supporter, or they can heat fusing to crude fibre.The bi-component crude fibre that contains fusible sheath can be used for fine fibre is thermally bonded on the crude fibre.Can adopt solvent bonding, can use the heat adhesive fibre technology, can adopt autogenous bonding.For adhesive, can adopt the water-soluble or solvent-based resin system of wet-laying.In some systems, can adopt urethanes spraying, hot melt spraying or hot melt sheet.In some cases, be anticipated that, do not need to make the fine fiber webs front to be fixed to adhesive on the thick supporter.They comprise such system at least, and wherein when making total compound, fine fibre is fixed between the unsawn timber bed of material, and the position between the two-layer roughage is used in the original place fixedly fine fiber layer or net.

Here the fine fiber layer that contains " fine fibre " or " network or the net " of fine fibre have been mentioned.In the context relation here, fine fibre " network " or " net " mean the material that not only refers to contain single fine fibre, and refer to net or network, and wherein material contains fiber or the fibrillation that joins each other or intersect in node or crosspoint.The example that this row puts will be described in detail as shown in figure 20 below.

Look back figure, can find out that the network of thin material contains many very thin fibers or bundle usually, wherein have some to stretch out from node or crosspoint.

Some signs of F are used for structure of the present invention

The method of one deck medium

Usually, apparent by above-mentioned explanation, one deck medium that is used for structure of the present invention generally includes thick supporter or base material, and wherein one deck fine fibre or fine fiber webs are fixed on its at least one surface.Thick supporter (or base material) and fine fibre can be usually aforesaid.Whole layer can characterize with several different methods, for example comprises simply as comprises above-mentioned thick and fine fibre, also arranges as shown.

Resemble and comprise fine fibre and coarse-fibred " mixture ", it is inaccurate characterizing preferable medium of the present invention like this.Usually material be not be made into as the mixture of fiber, promptly wherein the row that tangles of fiber puts.But fiber in medium, be positioned at separation with discontinuous band or district.Or rather, any one given layered composite all comprises usually and has the unsawn timber bed of material in its surface that at least one is applied with thin material.Even when the medium that provides be multilayer (piling up) row when putting, at air-flow during through " stacking material ", usually fine fibre and crude fibre district be earlier, the back impacted.

Apparent by the leader here, several different methods can both be used for preparing of the present invention pile up row put.Some of them, for example when embodiment be layer when carrying out wet-laying, can have some fine fibres and coarse-fibred entanglement.Certainly the entanglement degree can not reach fine fibre and crude fibre becomes " mixture uniformly " such degree, otherwise medium will can not move according to the principle of the invention ideally.Usually the unsawn timber bed of material still is used for different fine fiber layer is separated from each other in row puts.Here, when fine fiber layer is described to relative to each other when " separating " with respect to the crude fibre layer, it does not also mean that absolute not entanglement, but structure is such: when the fluid that filter was put through row, the fine fiber layer environment of promptly separating of multilayer was provided and is used for filtering.Usually, this refers to that (when layer is discontinuous) this issuable entanglement is lower.Tangle if produce between fine fiber layer and the crude fibre layer, it only relates to less fine fibre usually, typically is lower than 15% (weight).

A result who has said structure is not provide uniform filter media to air-flow.Promptly when air communication is crossed filter row and put,, can run into different materials in the different degree of depth or level.For example, in some systems, out-of-date when air communication, it can be arranged through fine fibre material alternately and roughage.Just formed important advantage thus.

In typical row put, the composite bed of medium can characterize with regard to the fine fibre quality that is applied on thick supporter or the sparse thing per surface area.It is sometimes referred to as the Unit Weight of fine fiber layer.This specific character will become with used special fiber diameter, selected certain material, the desired fibre diameter of layer and specific fine fibre gross density or filter clogging effect.Be anticipated that, be about in the typical preferred structure of 0.1-5.0 micron that the quality of materials of the formation fine fibre that is applied will be about 0.2-25 gram/rice on sparse thing of per surface area or thick supporter (or base material) at the fine fibre diameter ², it and used certain material are irrelevant.

Characterizing the another kind of method of the typical and preferred dielectric layer in the structure of the present invention, is the void content between unlimited or visible fiber when observing crude fibre supporter or sparse thing (from the fine fibre side), and it is by fine fibre or fine fiber webs is occupied or covering.Partly, can understand this characterizing method from Figure 16-20.

Figure 16-20 is the different sparse matter sample electron scanning micrographs under different magnifying powers that have fine fiber webs of the present invention on the surface.Thick supporter comprises the polyester fiber base material that diameter is the 25-35 micron.Fine fibre contains the glass fibre of the about 0.1-3 micron of diameter usually.

By the area percentage of open aperture in the occupied sparse thing of fine fibre area, can estimate by the SEM shown in Figure 16-20 (SEMs) evaluation method.Be anticipated that for typical and preferred construction of the present invention, the mean percentage of open area in thick supporter that occupies by fine fibre or the sparse thing, when adopting this method to estimate, to be 55% or below, typically about 20-40% is for preferred air cleaner medium.This does not represent that the structure outside these scopes is not all right, but such percentage is typical, and can move and effectively material is relevant.

Can characterize the another kind of method of some layers of material of the present invention, this layer can be arranged and be used for described filtration device structure, is when material is tested in air stream, about the observation to performance.Especially many preferred embodiment in, usually in air-flow as after the testing efficiency described here, can observe most of particles (with the quality and quantity dual mode) that tegillum dams, rather than by thicker structure by the combination of fine fibre institute.An one example is shown in the electron micrograph of Figure 21.

Alternately or similarly, empirical observation, the efficient of any given composite bed can both be assigned with.Generally speaking, if comprise crude fibre support structure or base material that average diameter is at least 10 microns fiber, and when the time as described here the evaluation, also have 6% or following efficient for the particle of 0.78 μ, one deck fine fibre improves by applying at least (wherein the average diameter of fine fibre is about 5 microns or following) for it, make improved material particle for 0.78 μ that is limited when test, has efficient at least about 8%, preferably at least 10%, so at least, preferably arrange in some the present invention and put, this structure will have at least some desired performances.Preferably, material comprises for 0.78 μ particle efficient and is about 4% sparse thing, and enough thin fiber is applied on this sparse thing, provides at least 10% or higher combined efficiency for 0.78 μ particle.In this row puts, the permeability that the crude fibre layer does not preferably apply fine fiber layer on it be 250-450 rice/minute material.Typically, also arrange the fine fibre material like this: make the permeability of the single composite bed of fine fibre/crude fibre composition be at least about 10 meters/minute, more preferably be at least about 25 meters/minute.Under some occasions, it can be elected to be quite high, promptly 100-325 rice/minute.

The G permeability

Here the permeability that relates to these materials: any given scrim material layer, have at least the sparse layer of one deck fine fibre or compound and total dielectric composite on it." permeability " be meant the plane lamella that passes with reference to material, medium or compound with reference to numerical value the time cause the required positive face velocity (air) of fluid resistance of 0.50 inches of water(in H in the face of medium.

Generally speaking, the permeability of dielectric layer (referring to used speech here) adopts the Frazier Precision Instrument Co. available from Maryland State Gaithersburg, Inc. Frazier Perm Tester, estimate by Frazier Perm Test according to ASTM D737, or by some similar method of testing evaluations.

When especially air filtration in being used for car hold, ventilation system or engine charge system, total permeability that the typical medium of the present invention row puts at least 6 meters/minutes, more preferably 10-12 rice/minute, permeability is the function of the size of gross efficiency, the number of plies and selected fiber.Here " always " is meant whole folded medium.

H efficient

Here from start to finish, can mention the efficient of one deck or compound constantly with concrete numerical value.That is, can describe constantly and have at least the sparse thing of one deck fine fibre material or the preferred efficient percentage of the sparse thing of selected one deck on it.In some cases, also get in touch the whole compound that contains multilayer material and describe efficiency value (%).In these context relations, for numerical representation method is provided, when the material that will characterize is tested (introducing for your guidance) here according to the ASTM1215-89 method, " efficient " typically is often referred to the test particle percentage of reservation, the test material that uses in the test is that diameter is 0.78 micron a monodisperse polystyrene latex balloon, for example available from the Duke Scientific that adds the inferior Palo Alto of livre Buddhist nun, test is carried out under 20 feet per minute clocks (about 6 meters/minute).

Above-mentioned explanation is not hinting: when filter of the present invention row puts usually when being described to " effectively ", only be meant the operation in filtration 0.78 micro particles under ASTM 1215-89 test condition.But be a kind of relative reproducible method for this particle with efficient under such test condition, according to said method the used material that maybe will use can be estimated or be characterized in structure of the present invention.

The interfibrous space of I, the fine fibre weight of being used on the thick base material of unit are

As mentioned above, material of the present invention can characterize with regard to the amount (Unit Weight) of the fine fibre material that applied on its fibrous septum or thick base material of unit are or the sparse thing.Effective method is as described below.

1. pass through the area solids content of digital image analysis

Here used method is the SEM photo scanning to be gone into computer carry out graphical analysis.Effectively the SEM multiplication factor depends on the fiber size that plays an important role in dielectric structure, and should select like this: make the fiber edge that will analyze clear in background.Multiplication factor increases, and the depth of field reduces.After the scanning, can adopt for example Visilog (available from the Noesis Vision ofVille St.Laurent of Quebec, CAN) of commercial software, by regulating the gray level thresholding of determining prospect and background border, image is divided into prospect and background, and the gray level image of scanning changed into binary image (prospect and background), can separate prospect and background binary image more subtly by adopting etching and enlarging to order.Important item is the fine fibre in the prospect.(suppose that medium comprises fine fibre and only is applied to sparse thing on the one surface, also hypothesis will show that the direction of SEM of fine fibre is towards the observer).In case separate, be used for the screen pixels of display foreground and background just can adopt the interior analysis tool of software to add up.Be used for the number of pixels of display foreground (fine fibre) divided by the number of pixels (AOI equals prospect and adds background) that shows AOI, and this ratio that obtains has been represented the area solids content.The structure of fiber is three-dimensional, and the SEM photo is represented the projection of three-dimensional body on plane or area, therefore adopts term " solids content of area ".

The numerical analysis of 2 hole dimensions

Here used method is the SEM photo scanning to be gone into computer carry out graphical analysis, adopts once more available from for example software of Noesis Visions Visilog.Effectively the SEM multiplication factor depends on the fiber size that plays the importance effect in dielectric structure, and should select like this: make the fiber edge that will analyze clear in background.Multiplication factor increases, and the depth of field reduces.After the scanning, can adopt for example Visilog of Noesis Vision of the software that can buy, by regulating the gray level thresholding of determining prospect and background border, and the gray level image that scans is changed into binary image (prospect and background), image is divided into prospect and background.Order and to separate more subtly with enlarging by adopting etching.Important item is by fibroplastic hole in the prospect.Next step is unusual item concerning the analysis tool of software in the AOI of image, need remove from AOI.This abnormality comprises the hole of protrusion and the hole that part is positioned at original AOI, and promptly the border in these holes is not definite fully.Then can use Software tool in Pixel Dimensions, to calculate each former crisp girth, area and aspect ratio in the corrected AOI.Form factor for the hole in each corrected AOI is defined as:

(4 π * hole area)/(the hole girth of measurement) ²Can both obtain calculating.From scanning resolution, SEM photo multiplication factor, software output, just can convert interfibrous spacing dimension to engineering unit from pixel unit.Should repeat this step with enough number of times, with the representational figure (or distribution) that guarantees to obtain sample.

The cross method of 3 line style fibers

At first, the break forth SEM photo of dielectric sample of suitable multiplication factor that the fiber size that can judge medium distributes and number.For fiber size, multiplication factor typically is changed to more than 6000 from 1000.Make on the another set of SEM photo that occurs 15-50 hole in the photo at least by the amplification degree, on this SEM (copy of an amplification) that the line lattice that are formed by straight lines can be added to.Several the straight lines that utilization is selected from the line lattice of stack at random, the fiber number that intersects with the grid straight line of selecting at random just can be come out, and so just can obtain the number of crossovers on the per inch line.By the number of the bigger straight line of quantity on the cumulative statistics, just can calculate interfibrous average headway, and make fiber spacing from distribution.Should repeat this step with enough number of times, with the representational figure (or distribution) that guarantees to obtain this sample.

4 Unit Weights

Be applied to thick supporter of unit are (surface area) or (poundage/3000 foot for example of the fine fibre weight on the base material at interval ²Or gram number/rice ²), can be used for estimating the spacing dimension of fiber, because in typical structure, important fine fibre pad is approximately single fiber layer.In addition,, can determine the thickness of fiber mat so if fibre structure is not an individual layer, then, solids content that can computed volume, it is an index in interfibrous space.

5 hole dimensions

A. the drum of mitered

Usually, the place that the fibrage contact is close supposes that the hole is tetragonal, and fiber intersects sideling, and each layer is randomly directed relative to each other.With reference to " filtering flow: gas volume 1 ", ASTM special technology publishing house 975, 1986, and ASTM publishes 04-975001-39, Donald R.Monson-" key parameter that is used for the pressure loss of analog filters fiber medium ".

On the opposite of the square hole of L=hypothesis between the parallel fibers

Center line distance from

d _fThe average diameter of=fiber

B=L-d _fThe size of=endoporus does not comprise the fibre that constitutes the hole

Dimension thickness,

C=solids content=fiber volume/medium volume

R＝L/d _f

Utilize above-mentioned definition, consistent measurement unit and the following formula that proposes by Monson, just can estimate interfibrous distance " b " from following formula:

R＝1/{1.1781-(1.3879-1.5×C) ^1/2}

b＝(R-1)×d _f

B. improved mitered drum

This model has been corrected the spacing between the continuous fiber layer, has supposed internal layer distance L/2, thinks that it is effective for the situation of C＜0.6.

R＝1.4472/(.5×C) ^1/2×COS{1/3×COS ^-1

[-0.87979×(.5×C) ^1/2]}

b＝(R-1)×d _f

C. the mitered drum of improved individual fiber structures

R＝(0.5×π/C)+({0.5×π/C} ²-{8/[3×C]}) ^1/2

b＝(R-1)×d _f

The filter media that J utilizes the principle of the invention to make

The design of compound

From above-mentioned explanation, what can understand is, adopts the filtration device structure of medium of the present invention to be made of medium usually, and this medium contains layers of fine fiber, more precisely the layers of fine fiber that is separated or separate by thick scrim material or crude fibre base material.In the occasion of many design air filtration device structures, the engineer will select the character of each layer, and determines how they should form total compound.In this section, the relevant consideration of technology therewith is discussed briefly.

Generally speaking, select partly to depend on the application that to use filter media, and depend on how to make medium.For the filter designer, predetermined application determines usually to needed filter clogging effect and infiltrative definite.For given application, efficient can also be determined by additive method except being determined by the ability of catching 0.78 micro particles under above-mentioned test condition.For example, the auto-maker can have concrete specification requirement, filter engineer can utilize material of the present invention to satisfy it to the operation of air cleaner in the cabin.Can determine this technical indicator not being equivalent to the ability of catching the trapped particle under the determined test condition of 0.78 micro particles.The engineer can adopt technology described here to approach possible structure, then, proposes suitable method of testing, observes the specification requirement that the auto-maker proposes and is met.As a kind of alternative method, through after the test of enough number of times, the engineer can be according to the test of being carried out under another kind of condition, and the data that propose fully to be correlated with can be predicted the performance under a certain class condition.

In any case, be anticipated that in a word in some cases, design procedure will be considered the material with performance of the present invention that can buy from the engineer.As an example, the engineer can select sparse thing, and obtains the sample of various scrim material, is applied with the fine fibre material of different amounts on the described scrim material.As the example of a hypothesis, suppose that the engineer has the various scrim material samples that contain Reemay 2011, they are only handled with the different fine fibre glass materials of measuring on one surface, form 8 samples, and wherein fine fiber layer characterizes as follows:

Glass fibre Schuller #106 ¹(0.4 micron) fiber				0.44 foot of area ²
Glass fibre Schuller #106 ¹(0.4 micron) fiber				0.44 foot of area ²		Glass weight (gram) in the hand papermaking former slurry	The permeability of individual layer (foot/rice)	Individual layer LEFS efficient (%)		Slurry glass weight/unit are
Gram/foot ²	Gram/rice ²	Pound/3000 feet ²								Slurry glass weight/unit are
Gram/foot ²	Gram/rice ²	Pound/3000 feet ²	????0.035	????818.6	??6.7％					????0.079	??0.848	????0.520
????0.040	????686.1	??8.8％	????0.035	????818.6	??6.7％		????0.090	??0.969	????0.595	????0.079	??0.848	????0.520
????0.040	????686.1	??8.8％	????0.075	????282.2	??25.5％		????0.090	??0.969	????0.595	????0.169	??1.816	????1.115
????0.100	????189.7	??32.6％	????0.075	????282.2	??25.5％		????0.225	??2.422	????1.487	????0.169	??1.816	????1.115
????0.100	????189.7	??32.6％	????0.150	????123.8	??54.5％		????0.225	??2.422	????1.487	????0.338	??3.633	????2.230
????0.200	????88.0	??68.8％	????0.150	????123.8	??54.5％		????0.450	??4.844	????2.974	????0.338	??3.633	????2.230
????0.200	????88.0	??68.8％	????0.380	????33.7	??94.3％		????0.450	??4.844	????2.974	????0.855	??9.203	????5.650
????0.600	????21.0	??99.1％	????0.380	????33.7	??94.3％		????1.350	??14.531	????8.921	????0.855	??9.203	????5.650

¹Schuller #106 is that average fibre diameter is 0.4 micron a glass fibre, available from the Schuller Filtration of Colorado 80162 Littleton.

Provide above-mentioned information and material, the filter engineer can design.Generally speaking, under the test condition of regulation, compound is every layer of efficient " summation " for the efficient of 0.78 micro particles.For example, if use is two-layer, wherein every layer of efficient is 35%, and gross efficiency is 1-[(1-0.35 just so) * (1-0.35)] or 57.75%.Therefore, in order to obtain desired efficient, by the information of known different layers, how many layer and which kind of materials the engineer just can determine to use.

In the explanation in front, provided the general formula of definite multilayer system internal efficiency.Can carry out concrete calculating according to following principle:

Particle size and speed for regulation:

η _iThe efficient of=the i layer

η _tThe efficient of=total compound

1-η _iThe transmitance of=the i layer

1-η _tThe transmitance of=total compound

(1-η _t)＝(1-η ₁)(1-η ₂)…(1-η _i)

In a word, total permeance property of compound is determined by the permeability of each layer in the compound according to following relationship.

X wherein _CompoundThe permeability of=total compound

ρ _i=according to structure comprise slightly+thin layer or the compound that only comprises thick layer form the permeability of layer.

Therefore, use about the infiltrative knowledge of each layer, the engineer just can know the permeability of total compound, and can select different layers desired specific permeability is provided.As an example, the positive face velocity of typical case of air cleaner is 50-70 feet per minute clock (about 15-24 rice/minute) in the cabin, arranges and puts the foot at 220-300 ³/ minute (about 6.2-8.5 rice ³/ minute) air-flow down during operation.For example use the filter of making by following combination just can satisfy this requirement:

1 efficient is 30% anterior layer or base material;

2 efficient are 35% adjacent lower floor or base material;

3 efficient are 45% adjacent lower floor or base material; The efficient of compound just is about 75%.

So, can find out, if the engineer knows how many permeability of desired total compound is (determining under the infiltrative test condition of given layer being used for), and the engineer has determined the efficient of each layer, and how much efficient of knowing desired total compound under condition of similarity is, the engineer just can easily select material so, reaches desired result.

Certainly, the engineer can wish to consider other variable or factor.For example for thin compound, only have the number of plies seldom, and in some cases, obtain preferred total combination, whether cost, the available material of any given layer can be bought and obtain and factor that other are relevant also is to need to consider.And to consider the formed physical property of compound, for example about the easy formability of foldable structure.

An example of the problem types that can consider when selecting material as the filter designer is as follows.If two area identical materials fold, one of them is in fact thick than another, and generally speaking, it will be more can effectively piling to the fold number than sheeting in the constant volume.Therefore, if the design problem of filter is to form effective filter in given cylindric space, the engineer just can preferably not select thicker material than thin folding material so.If folding material will be made by dielectric layer of the present invention, the engineer just can preferentially select the laminar composition that can form thin general construction so, and with respect to thicker general construction, it has advantage.

Yet generally speaking, when the compound with equal gross efficiency compared, thicker compound is relatively thinner usually had longer useful life (under equal area).When some systems of design, the engineer can carry out balance coordination according to this factor and aforementioned consideration.

Predictably, in some cases, the engineer can wish to make all layers of stacking material to contain same composite.Yet, under other situations, can in some or all of each layers, use different material (or efficient etc.).Be anticipated that in typical operation, if engineer's decision makes the efficient difference in compound middle level, so generally speaking, formed efficiency gradient becomes prioritization like this: the efficient of composite layer increases usually on the direction of direction structure lower floor.That is, be anticipated that at present that preferred layer tissue will be that the higher composite layer of the efficient composite layer lower than efficient is in the more position of lower floor, make to form longer useful life.Usually the reason that forms than long life is in this case, if the higher layer of efficient be positioned at downside just can not be very fast blocked because the lower layer of efficient just worked before fluid arrives the higher layer of efficient, provide to the small part filtration.This means that the higher layer of efficient can be blocked more slowly when being positioned at upside.

The K geometry

Medium of the present invention can be arranged with multiple geometrical configuration, obtains advantage.For example plain film can be arranged in simple stacking material, form non-folding types of filters medium.

Certainly, sheet can be arranged in bed course or roll around a kind of object, for example around the rolled-up cylinder of cylindrical structure.

Uniquely, medium of the present invention can provide with this form: it can easily fold.In some cases, it will be realized by such mode: select sparse thing at interval, make when piling up formed compound have enough intensity or " base substrate " and fold and keep folded configuration.Shown in Fig. 8 A and 8B.

With reference to Fig. 8 A, filter media 30 is illustrated with folding cylindric configuration.In Fig. 8 B, the part material is excessively enlarged and illustrates, and purpose is to understand that material comprises many layers.With reference to Fig. 8 B, material 30 comprises thick layer 31, and fine fiber layer 32 is between it.Generally speaking, be anticipated that, put for many preferred rows, no matter be arranged in cylindric or tabular, the number of fold all be about 1-15 individual/inch (or/2.5 centimetres).When describe be cylindric configuration the time, the fold number on the unit distance of being reported is meant on the internal diameter of cylindrical structure here.

Folding cylindric configuration of the present invention is unique, and its reason is the positive face velocity of medium of the present invention with regard to load and operation at least, greatly shows the performance of deep layer medium system.Yet conventional deep layer medium does not normally fold.Or rather, foldable structure is relevant with paper or cellulose surface load system usually.Yet, can utilize principle of the present invention, the form operation with the deep layer medium is provided, but can puts with the row that folding mode is shaped, this folding mode is more similar to the surface load cellulose media.

Be noted that for some rows and put, can provide sinusoidal (ripple or similar fold) sample, even medium does not provide enough base substrates to keep real folded configuration.Can predict its several implementation methods.At first, " base substrate " can be by having only one deck or which floor the material with sufficient base substrate (in medium) to provide.For example, one deck in the multilayer system or two-layer sparse thing are just enough for this base substrate, do not need all layers all to have it.In addition or another kind of mode be that layer of support material on piling up the one or both sides put of row or in it can be used to provide this base substrate or mechanics integrality.This compound can adopt and can buy synthetic or cellulose fibre is made as supporting layer.

Providing does not have thick sparse layer and forms the second method that the sine row of fold puts, and is to utilize mechanical frame to keep material to be in foldable structure.This schematic diagram as shown in Figure 9.In Fig. 9, show mechanics strut 40, and medium 41 is through above it.

Other method can comprise sufficient heat, chemistry or the physical treatment of material, provides enough rigidity to keep folded configuration or fold.Also can use the bonding method of fold end point.Also can use the metal tape that is positioned at the different composite layer or line to keep the configuration that folds.

Apparent by above-mentioned consideration, advantage of the present invention is that it can be used with the material that multiple geometry can be provided.Therefore, it can be used with a variety of filtration device structures, obtains advantage.As mentioned above,, can select the performance of material, make the needed degree of depth can be with requiring and become for effective operation.

The L air filter arrangement

Medium of the present invention can be applied in the multiple air filter arrangement.It can be as the cylinder folding material in the cylinder element for example.It also can be as the folding material of plate class filter.It can use with non-folded form, for example as in other filter cells or the outer sleeve filter of other filter cells.It also can be used for cylinder and fuel plate with non-folded form.Really, it can be used for replacing medium or part medium at almost in any one of multiple filtration or filter system.

In some cases, medium of the present invention can be used for strengthening the operation of other media, the other types medium that for example can buy.Therefore, medium of the present invention can be applied to various dielectric layers front, back or between, realize preferred filter operation.For example, high efficiency type medium of the present invention can be used in the back of various media, as bright filter.The medium of top load of the present invention, inefficient type can be used in the front of conventional media, by improving gross efficiency as the top load medium in front.Medium of the present invention also can be used between the conventional media in various gradient filter systems or relevant system.

A kind of filtration device structure type of the present invention is shown in Figure 10 and 11.Row among Figure 10 puts usually and United States Patent (USP) 4,720,292 (here introducing for your guidance) is described similar, and different is to have replaced filter media with improvement medium of the present invention.With reference to Figure 10, shown filter row puts 100 and comprises shell 101, outlet 102 and filter cell 103.Process hacures or coating 105 have just entered the internal layer 104 of the shell 101 of maintenance filter element 103.

Filter cell 103 contains folding filter media 110, outer lining 111 and liner 112 usually.Put for row shown in Figure 10, air passes through along the general direction of arrow 115, just produces and filters.Therefore, shell 101 comprises the inlet 120 of wanting filtered air.Air is flowed through before the filter cell 103, is distributed in the chamber 121.Air enters inner room or inner chamber 122 then, leaves filter cell by exporting 102.

Filter cell 103 comprises relative first and second end caps 130 and 131 respectively.Filter media 110 is fixed to, embeds in end cap 130 and 131 and stretches between them.In zone 140, end cap 130 is with its size and configuration and outlet 102 formation sealings radially.End cap 131 is the end 142 of enclosed filters element 103 in a usual manner.

In Figure 11, illustrate part row shown in Figure 10 with schematic cross section and put.Can find out that filter media 110 is that multilayer row of the present invention puts, and comprises many unsawn timber bed of materials 150 and fine fibre material layer 151 at interval.Given row shown in Figure 10 is put and is contained two-layer isolated fine fiber layer 151, and they are add up to three layers thick layer 150 clamping.Explanation again, according to principle of the present invention, multiple interchangeable row puts and can be used as filter media 110.

Medium shown in Figure 10 and 11 is introduced with cylindrical member, constitutes radial seal with outlet.Medium also can be used for the filter cell that axial seal row puts.

Generally speaking, the present invention can be used for preparing such medium: when comparing with the surface load medium, and its load bearing capacity height, and when being used for filtering the fine particle material, the material thicker with filtering collection compared, its load advantage is considered to more remarkable.Therefore, by of the present invention folding and will fold the lower floor that thing is positioned over some deep layer media, just can obtain this advantage, because the deep layer medium can be collected corase particles relatively efficiently, again owing to there be of the present invention medium high, thereby strengthened filtration to the fine particle physical efficiency.Deep layer medium above utilizing is made the higher filter of efficient, at United States Patent (USP) 5,082, description is arranged in 476,5,238,474 and 5,364,436; Utilize similar technique, but below use of the present invention medium different with the deep layer medium, just can obtain advantage.For example, can be used for removing very effectively the particle of 2-10 micron in the above as the described deep layer medium of above-mentioned patent, this deep layer medium is different with medium of the present invention, and medium of the present invention is used for removing below secondary micron material, reach very high efficient, thus, medium of the present invention just can together use with mode preferably and conventional technology.

In some applications, medium of the present invention can be shaped as non-folded form, but it be positioned at the deep layer medium below, use with the form of tabular or cylinder-shaped filter element.Medium can be and the separable assembly of filter for installation remainder for example durable replacement element.Medium of the present invention also can be used in above the filter assemblies, as replacing element.The method that adopts replaceable medium part is for example at above-mentioned United States Patent (USP), also have description at U.S. Patent application 08/426,220, and they are here introduced for your guidance.

The location of M fine fibre on thick supporter, fine fiber layer is with respect to the orientation of fluid

As mentioned above, filter material of the present invention contains thick supporter usually, is applied with fine fiber webs or pad on its at least one surface.As meeting was understood from the assessment of accompanying drawing, generally speaking, the crude fibre supporter can be considered as having two surfaces that can apply fine fibre, all can apply one on every on the crude fibre pad.At least in some useful system, why the fine fibre pad can not be applied on the opposite face of one deck roughage, does not have special reason.Roughage or base material are used for separating aptly the fine fibre pad.Be anticipated that, use, in some cases, can require between the unsawn timber bed of material that has fine fibre on its two sides, to place layer or the sparse thing that one deck only contains roughage, keep the separation between every layer of fine fibre if this row puts in stacked mode.Yet, certainly possiblely be: under some occasions, can select the fine fibre amount that applied, make be placed to directly with another thick layer on fine fiber layer when adjacent, just can form desired gross efficiency.

In stacked row puts,, do not aware particularly preferred direction about the orientation of material with respect to air-flow.That is, fine fiber layer can be on the upper surface or lower surface of the pad that applies fine fiber layer.

N is used for the selection that the present invention arranges the medium of putting

As mentioned above, it has been generally acknowledged that at present, relate to the relevant maximally related key element of selecting the medium of material and be make crude fibre well mutual spacing, relatively say filtration hardly, be positioned properly to support fine fibre and to keep fine fiber layer separated from one another relevant in general construction.The diameter of fine fibre is elected as less relatively.Thus, can predict, multiple material can both be used for structure of the present invention, and multiple technologies all can be used to make this material.

Generally speaking, the technology of preparing that is used for the fibrous material of filtration device structure of the present invention does not belong to the category of putting into practice of filter designer or engineer's routine, but belongs to fiber process and Polymer Processing category.Can predict, for example the Hollingsworth ﹠amp of the East Walpole of Massachusetts 03032; The Lydall Inc. company of the Rochester of Vose company and New Hampshire 03867 is making the fine fibre material or they is being had rich experience with the technical elements that layer is administered on the other materials.As mentioned above, DonaldsonCompany Inc. has also developed some and has belonged to the technology of business secret in the field of relevant its Ultra-Web  product.

Quote following list of references for your guidance here, always described the manufacturing of fine fibre or superfine fibre: United States Patent (USP) 2,450,363 (about glass fibres); 4,650,506; A.1956, Wente, Van are published in the article " thermoplasticity superfine fibre " of the 1342nd page of Industrial Engineering Chemistry the 48th volume year; And Schoffel, B.1995 Norman is published in the article " new development of little glass medium " of Advances In Filtration andSeparation Technology the 9th volume 184-199 page or leaf year.Generally speaking, can predict, many these materials can both be as the fine fiber webs in the structure of the present invention.

About crude fibre pad or base material, explanation comprises that at least the multiple material of buying the material that obtains described here is available once more.

Make fine fiber webs and it is administered to the lip-deep technology of roughage about being used for, explanation once more, the whole bag of tricks can use, can predict, for any given application, preferable methods partly depends on the application of filter, used process equipment at least, the certain material of selecting for fine fiber webs, material and the technology that is used for making the crude fibre base material.Generally speaking, at least for example these technologies of the spinning of wet laying process, air-laid process, melt-blown process and polymer fiber are available.

For useful filtration device structure, although at present unpredictable most preferred specific fibre manufacture or material composition, the inventor estimates and has contrasted the medium of being made by two kinds of methods.A kind of is to utilize the fine fibre that comprises glass, and the possible method as the preparation medium is administered to Reemay 2011.Find that this technology made spendable medium, satisfy total standard of the present invention.Another kind is the polymeric fine fibers that the business secret Ultra-Web  technology of employing Donaldson Co. is made, and fine fibre is administered to Reemay2011.

Specifically, about glass fibre, the inventor successfully utilizes with United States Patent (USP) 5,336, and the described method that becomes example into foundation of embodiment 1 is made available material in 286 (here the introducing for your guidance).Glass or glass fibre are used as the fibrous material that will use, and are used as the material of the sparse thing of fine fibre deposition Reemay2011 thereon, to 5,336, the embodiment 1 of 286 patents improves.In addition, put into 2 milliliters HCl acid (37%) in the water/fibre stuff in the cooker mixer, make the glass fibre chemical dispersion.

Therefore,, form the wet-laying deposit, make fibre plate by placing glass fibre on the 2011 sparse things of the Reemay above being positioned at web plate as the result of modification.

Other samples that the technology that changes is made are compared to some extent in employing with the business secret Ultra-Web  technology of Donaldson Co., as described below.

In the compare test below,, do not observe substantial difference for the performance of two types of materials.Therefore, according to principle of the present invention, between them, there is not the basis of preferred selection.

The application of technology aspect the smog collection that O is described here

Generally speaking, can predict, some materials described here can be used for filtering the structure of very thin smog from air.Generally speaking, this smog comprises size about 1 micron or littler drop.In order to estimate filtration, to a certain extent, the smog of size can be regarded particle as and handles like this.So, some material described here just can be used for catching this smog.Generally speaking, do not need space (being the hole) between the typical little fiber of efficient smoke filter medium, just can obtain high efficiency separation.The aperture of conventional efficient medium is because capillarity can keep isolated liquid.The liquid of retaining in the system increases fast like this, forms the obstruction of liquid to circulation of air, and this can shorten useful filter useful life.Can predict, for such application, can use the fiber surface of the liquid of hating collection, this is favourable.

P. fluid filter system

Usually, the techniques described herein can be used for relating to the occasion of various liquid streams.The many specific description that provides up to now is relevant with air that carries particulate or gas stream.But, can predict the system that material as herein described also can be used for supplying filter liquide.That is, liquid can be guided by medium of the present invention, and as revealed separated like that of particulate wherein.

In general, if be used for liquid system, can predict, the principle that the fine fibre number of plies that is spaced by increase increases filter medium life for liquid be identical for air, still, the mechanism of collection is filtration.Because the mechanism of collecting is to filter, the individual layer efficient that is had peak efficiency in the efficient of using compound in the liquid occasion limits.The typical efficiencies scope of using liquid be from for lubricating oil about 50% to for fuel filter medium about 99%.Therefore, than the air filtering system that in air filtering system, uses low combined efficiency, as gas-turbine, mechanical air induction system, cabin and room air ventilating system, the example of the present invention that is applied on the fluid filter system generally is made up of each layer with higher level efficient.When in needs high-efficiency air filtering occasion, filter as the HEPA level in ventilating system or ULPA level that the present invention also has a lot of favourable parts when using in the occasion.Favourable part of the present invention is to filter long service life, and by multilayer and more reliable.By the tediously long filtration of multilayer, overall system descends for the medium crack sensitiveness in the individual layer.

Q. further comment

When in the experiment of following report, having assessed material, also done further observation for the preferred material that the present invention is specific.At first, coarse base material or matrix can become integral body with superfine fiber and works, thereby have reduced manufacturing, processing or the impaired possibility of fine fibre when using.Do not have coarse supporter or matrix, the fine fiber structure thing very easily is damaged when contacting with other material.But it is so durable that the present invention preferably arranges thing, so that can predict that prepared works can wash by liquid or by the air douche cleaning, for the regeneration use after use.

Also need on base material, make arrangement thing of the present invention obviously by multiple air layer.For example, can put down the sparse layer of one deck porous, use the fine fibre goods then, re-use rough layer, re-use fine fibre fabric etc.Like this, the step by a plurality of laying air fibers according to the order of sequence can prepare total compound.This needs in specific processing is used.Can be contemplated that if in each layer, prepare essentially identical overall operation to be arranged for same works.

R. further comment again

1. the feature of microfibre length and/or microfibre surface area on Gu Suan the crude fibre supporter unit are

Propose in the chapters and sections discussion of front: characterize some preferred material with the microfibre weight that is applied on each unit are crude fibre base material, these preferred materials comprise some the fine fibre (being microfibre) that is applied on the rough wearing fiber supporter base material.About this problem, please note table in the J joint and the discussion in F joint and " I.4 " joint.Glass is the material that a class can be used for forming microfibre.About 2.6 gram per centimeters of the proportion of glass ³, about 2.6 gram per centimeters of the proportion of known glass ³For the glass fibre of given diameter, we obviously can be with " every square metre (area) crude fibre supporter medium on glass fibre length ", also can characterize the fine fibre consumption that is applied on the crude fibre base material with the glass fibre weight on every square metre.Because fiber has columniform outer surface usually, such sign also is fine: " the fine fibre surface area on each unit are of rough wearing fiber supporter medium ".

Following table R1 provides for selected glass fibre, by weight, and the microfibre surface area of on the microfibre length of estimating on every square metre of medium and every square metre of medium, estimating.Three kinds of glass fiber diameter are particularly provided: 0.1 micron diameter; 1.00 micron diameter; With 3.00 micron diameters.Three kinds of specific Unit Weights also are provided: 0.10 gram/square metre; 1.00 gram/square metre; With 10.00 the gram/square metre.Proportion 2.6 gram per centimeters according to these parameters and setting ³, this table provides representative to be used for the microfibre length on every square of medium and has been used for the quantity data of microfibre surface area on every square of medium.

Table R1

Fibre diameter (micron)	Unit Weight (gram/rice ²)	Microfibre length (the km of estimating on every square metre of medium/rice ²)	The microfibre surface area of estimating on every square metre of medium (rice ²/ rice ²)
Fibre diameter (micron)	Unit Weight (gram/rice ²)			????0.10	????0.10	????4,897	????1.54
????0.10	????1.00	????48,971	????15.38	????0.10	????0.10	????4,897	????1.54
????0.10	????1.00	????48,971	????15.38	????0.10	????10.00	????489,708	????153.85
????1.00	????0.10	????49	????0.15	????0.10	????10.00	????489,708	????153.85
????1.00	????0.10	????49	????0.15	????1.00	????1.00	????490	????1.54
????1.00	????10.00	????4,897	????15.38	????1.00	????1.00	????490	????1.54
????1.00	????10.00	????4,897	????15.38	????3.00	????0.10	????5	????0.05
????3.00	????1.00	????54	????0.51	????3.00	????0.10	????5	????0.05
????3.00	????1.00	????54	????0.51	????3.00	????10.00	????544	????5.13

Information for the ease of interpret table R1 provides now sees table R2.In table R2, the table that the J joint occurs is modified to and has comprised in the certain embodiments by specific gravity of glass 2.6 gram per centimeters of setting ³The length of 0.4 micron fiber that is applied down of calculating that provides and average fibre diameter and the surface area of fiber.

Table R2

Unit Weight (gram/rice ²)	LEFS (％)	Fine fibre length (the km/rice of unit media area ²)	The fine fibre surface area of unit media area (rice ²/ rice ²)
Unit Weight (gram/rice ²)	LEFS (％)	Fine fibre length (the km/rice of unit media area ²)		????0.85	???6.7％	????2,595	????3.26
????0.97	???8.8％	????2,966	????3.73	????0.85	???6.7％	????2,595	????3.26
????0.97	???8.8％	????2,966	????3.73	????1.82	??25.5％	????5,558	????6.98
????2.42	??32.6％	????7,413	????9.32	????1.82	??25.5％	????5,558	????6.98
????2.42	??32.6％	????7,413	????9.32	????3.63	??54.5％	????11,119	????13.97
????4.84	??68.8％	????14,826	????18.63	????3.63	??54.5％	????11,119	????13.97
????4.84	??68.8％	????14,826	????18.63	????9.20	??94.3％	????28,167	????35.40
????14.53	??99.1％	????44,475	????55.89	????9.20	??94.3％	????28,167	????35.40

Except calculating is according to the inferring of 2.20 microns of fibre diameters, following table R3 is similar to the form of table R2 performance.

Table R3

Unit Weight (gram/rice ²)	????LEFS ????(％)	Fine fibre length (the km/rice of per unit media area ²)	Fine fibre surface area/unit media area (rice ²/ rice ²)
Unit Weight (gram/rice ²)	????LEFS ????(％)	Fine fibre length (the km/rice of per unit media area ²)	Fine fibre surface area/unit media area (rice ²/ rice ²)	????2.86	????3.4％	????289	????2.00
????5.45	????10.1％	????551	????3.81	????2.86	????3.4％	????289	????2.00
????5.45	????10.1％	????551	????3.81	????5.57	????11.9％	????564	????3.90
????12.81	????19.2％	????1,296	????8.96	????5.57	????11.9％	????564	????3.90
????12.81	????19.2％	????1,296	????8.96	????16.95	????24.1％	????1,715	????11.86
????26.04	????35.6％	????2,634	????18.21	????16.95	????24.1％	????1,715	????11.86
????26.04	????35.6％	????2,634	????18.21	????50.40	????60.9％	????5,099	????35.24
????68.73	????72.1％	????6,954	????48.07	????50.40	????60.9％	????5,099	????35.24

In case the engineer has selected material, just can simulate this system according to calculating.Following table R4 has summarized the feature of glass fine fiber layer according to material thickness, fibre diameter and the unit Unit Weight set.

Table R4

The layer thickness of setting (micron)	Fibre diameter (micron)	Unit Weight (gram/rice ²)	Proportion (gram per centimeter ³)	Estimate LEFS (%)	Fine fibre length (the km/rice of per unit media area ²)	Fine fibre surface area/unit media area (rice ²/ rice ²)
The layer thickness of setting (micron)	Fibre diameter (micron)	Unit Weight (gram/rice ²)	Proportion (gram per centimeter ³)	Estimate LEFS (%)	Fine fibre length (the km/rice of per unit media area ²)	Fine fibre surface area/unit media area (rice ²/ rice ²)	????1.0	????0.20	????0.05	????2.6	????10％	????612	????0.38
????1.0	????0.20	????0.08	????2.6	????16％	????918	????0.58	????1.0	????0.20	????0.05	????2.6	????10％	????612	????0.38
????1.0	????0.20	????0.08	????2.6	????16％	????918	????0.58	????1.0	????0.20	????0.10	????2.6	????22％	????1,224	????0.77
????1.0	????0.20	????0.15	????2.6	????34％	????1,836	????1.15	????1.0	????0.20	????0.10	????2.6	????22％	????1,224	????0.77
????1.0	????0.20	????0.15	????2.6	????34％	????1,836	????1.15	????1.0	????0.20	????0.20	????2.6	????46％	????2,449	????1.54
????1.0	????0.20	????0.25	????2.6	????58％	????3,061	????1.92	????1.0	????0.20	????0.20	????2.6	????46％	????2,449	????1.54
????1.0	????0.20	????0.25	????2.6	????58％	????3,061	????1.92	????1.0	????0.20	????0.30	????2.6	????68％	????3,673	????2.31
????1.0	????0.20	????0.35	????2.6	????77％	????4,285	????2.69	????1.0	????0.20	????0.30	????2.6	????68％	????3,673	????2.31
????1.0	????0.20	????0.35	????2.6	????77％	????4,285	????2.69	????1.0	????0.20	????0.40	????2.6	????84％	????4,897	????3.08
????1.0	????0.20	????0.46	????2.6	????90％	????5,632	????3.54	????1.0	????0.20	????0.40	????2.6	????84％	????4,897	????3.08
????1.0	????0.20	????0.46	????2.6	????90％	????5,632	????3.54	????0.5	????0.20	????0.05	????2.6	????10％	????612	????0.38
????0.5	????0.20	????0.10	????2.6	????23％	????1,224	????0.77	????0.5	????0.20	????0.05	????2.6	????10％	????612	????0.38
????0.5	????0.20	????0.10	????2.6	????23％	????1,224	????0.77	????0.5	????0.20	????0.15	????2.6	????39％	????1,836	????1.15
????0.5	????0.20	????0.20	????2.6	????55％	????2,449	????1.54	????0.5	????0.20	????0.15	????2.6	????39％	????1,836	????1.15
????0.5	????0.20	????0.20	????2.6	????55％	????2,449	????1.54	????0.5	????0.20	????0.25	????2.6	????70％	????3,061	????1.92
????0.5	????0.20	????0.30	????2.6	????82％	????3,673	????2.31	????0.5	????0.20	????0.25	????2.6	????70％	????3,061	????1.92
????0.5	????0.20	????0.30	????2.6	????82％	????3,673	????2.31	????0.5	????0.20	????0.35	????2.6	????90％	????4,285	????2.69
????0.5	????0.20	????0.40	????2.6	????95％	????4,897	????3.08	????0.5	????0.20	????0.35	????2.6	????90％	????4,285	????2.69
????0.5	????0.20	????0.40	????2.6	????95％	????4,897	????3.08	????25	????5.00	????0.04	????2.6	????9％	????0.78	????0.01
????25	????5.00	????0.08	????2.6	????19％	????1.57	????0.02	????25	????5.00	????0.04	????2.6	????9％	????0.78	????0.01
????25	????5.00	????0.08	????2.6	????19％	????1.57	????0.02	????25	????5.00	????0.10	????2.6	????24％	????1.96	????0.03
????25	????5.00	????0.13	????2.6	????31％	????2.55	????0.04	????25	????5.00	????0.10	????2.6	????24％	????1.96	????0.03
????25	????5.00	????0.13	????2.6	????31％	????2.55	????0.04	????25	????5.00	????0.15	????2.6	????36％	????2.94	????0.05
????25	????5.00	????0.18	????2.6	????43％	????3.53	????0.06	????25	????5.00	????0.15	????2.6	????36％	????2.94	????0.05
????25	????5.00	????0.18	????2.6	????43％	????3.53	????0.06	????25	????5.00	????0.22	????2.6	????51％	????4.31	????0.07
????25	????5.00	????0.26	????2.6	????58％	????5.09	????0.08	????25	????5.00	????0.22	????2.6	????51％	????4.31	????0.07
????25	????5.00	????0.26	????2.6	????58％	????5.09	????0.08	????25	????5.00	????0.30	????2.6	????64％	????5.88	????0.09
????25	????5.00	????0.40	????2.6	????76％	????7.84	????0.12	????25	????5.00	????0.30	????2.6	????64％	????5.88	????0.09
????25	????5.00	????0.40	????2.6	????76％	????7.84	????0.12	????25	????5.00	????0.50	????2.6	????85％	????9.79	????0.15
????25	????5.00	????0.58	????2.6	????89％	????11.36	????0.18	????25	????5.00	????0.50	????2.6	????85％	????9.79	????0.15
????25	????5.00	????0.58	????2.6	????89％	????11.36	????0.18	????15	????5.00	????0.04	????2.6	????9％	????0.78	????0.01
????15	????5.00	????0.10	????2.6	????24％	????1.96	????0.03	????15	????5.00	????0.04	????2.6	????9％	????0.78	????0.01
????15	????5.00	????0.10	????2.6	????24％	????1.96	????0.03	????15	????5.00	????0.13	????2.6	????31％	????2.55	????0.04
????15	????5.00	????0.18	????2.6	????42％	????3.53	????0.06	????15	????5.00	????0.13	????2.6	????31％	????2.55	????0.04
????15	????5.00	????0.18	????2.6	????42％	????3.53	????0.06	????15	????5.00	????0.22	????2.6	????50％	????4.31	????0.07
????15	????5.00	????0.30	????2.6	????63％	????5.88	????0.09	????15	????5.00	????0.22	????2.6	????50％	????4.31	????0.07
????15	????5.00	????0.30	????2.6	????63％	????5.88	????0.09	????15	????5.00	????0.50	????2.6	????84％	????9.79	????0.15
????15	????5.00	????0.58	????2.6	????89％	????11.36	????0.18	????15	????5.00	????0.50	????2.6	????84％	????9.79	????0.15

That discusses as prosthomere is pointed with following experiment, and according to principle as herein described, the certain material that forms microfibre is not the key factor that obtains these beneficial effects in many cases.For the fiber consumption of any given diameter, or even more important for the fiber surface area amount of any given fiber for obtaining required filter effect.Table R1, R2, R3 and R4 table have provided the approach of " generally " that is applied to the fine fibre feature consumption on the base material (in general, described base material is nonspecific for the certain material of selecting).That is, by assessing consumption, length or the surface area of the fine fibre that applies on the per unit area, people can remove the variation of the proportion of assessment fine fibre material (being the specific composition of fine fibre material) from.In addition, the calculating of the glass fibre of use is represented for the given diameter fiber, the desired performance on the per unit area base material under a certain value of fibre length or fiber surface area.Similar with the fibre length on similar diameter, the per unit area, or the similar material of the fiber surface area on the per unit area replaces glass can obtain similar filtration character and efficient.

It should be noted that such as the fibre length on the per unit area it is to load effective indication character of density or solids content.Similarly, they have also described the geometry of fiber to a certain extent, especially under low Unit Weight.

2. the medium of static electrification

Pointed out that above fine fibre of the present invention can be connected with various types of media.Mentioned the possibility of neutral medium or static electrification medium above.

Especially predictably, for example, microfibre of the present invention can be used for the total composition comprising the partial-band electrostatic media.The static electrification medium is called as " electret " medium sometimes, and it can be used as the base material that applies microfibre; And/or it can be used as the separation layer of medium, is arranged in whole multilayer dielectricity compound: (a) upstream of micro fibre material; (b) downstream of micro fibre material; Or (c) between the micro fibre material layer.

By utilizing the static electrification medium can obtain various favourable works.For example, the static electrification medium has high relatively starting efficiency in many use occasions.But a problem of this class medium is that its efficient along with the time extends, descends to some extent with respect to starting efficiency.The medium of static electrification can be used for the top so that the starting efficiency of increase to be provided of microfibre medium of the present invention.Preferred medium was typically the medium of static electrification during this class was used, as E30, and a kind of charged fibrous material, ALL FELT of Genoa (Illinois, US 60135) makes.It has: Unit Weight 30 gram/rice ²0.024 inch of thickness is (at 0.5 pound/inch ²Down); Permeability (feet per minute clock) 600 ⁺LEFS efficient is 43%.Be typically, it is the same preferably not apply the LEFS efficient that the electrostatic charge medium has, and is not more than 80%, typically is 10% to 50% (20-50% is better).

Can predict, need coarse-fine fibre composition in some cases, comprise the static electrification part of microfibre itself.

In some application scenarios, not that the extra play with the static electrification material is applied on the total thing, provide one or more " supporters " or " sept " structure but apply in the arrangement thing of microfibre in the above.That is, microfibre can be applied directly on the base material of static electrification; Or after microfibre applies on it, base material is charged.

In a word, can predict, the approach that defines in these chapters and sections is to utilize the whole bag of tricks that medium is applied electrostatic charge, comprises conventional method.Can use commercially available material in some occasion.

3. use the medium that contains chemosorbent/absorbent

The term of this paper " adsorbent " refers to absorb and sorbing material.That is, do not consider interactional characteristic between captive chemical substance (particularly organic matter) and filtering material.

Various materials can be used as chemosorbent.For example, activated carbon or charcoal medium are used to adsorb smell and various other organic matter.

Developed the fibre-bearing medium, it comprises chemosorbent, as carbon particle.This class material is AQF ^TMAdsorbing medium, Hoechst Celanesee Corp. (North Carolina, USA 28232-6085) makes.Commercially available have various permeability (being typically 137-279 feet per minute clock), thickness (0.0661-0.0882 inch); Unit Weight (280-382 pound/3000 foot ²); MD (intensity) (the 17-30 pound/inch) that stretch.The preferred a kind of chemosorbent of this paper is AQF-375C, and it has following feature:

Unit Weight-480 gram/rice ²,

High-performance activated carbon-sphere,

Carbon content-375 gram/rice ²

The carbon ash moves-does not have;

Diameter-1.45 millimeter,

Hot strength-30 pound/inch,

Air permeability-160 foot ³/ foot ²/ minute,

300 feet of @ fall in pressure ³/ minute/foot ², 1.2 inches on plane;

Dynamically absorption @ is 100 feet ³/ minute air stream, 10 * 10 * 1.5 " filter has 0.63 meter ²Pleating medium:

80 ppm normal butane adsorption capacities-6.0 gram,

Chuan Tou @5 minute-40%;

80ppm toluene gas adsorption capacity-55 gram,

Chuan Tou @5 minute-7%;

30ppm 5O ₂Gas absorption capacity-9.2 gram,

Chuan Tou @5 minute-21%;

The removal efficiency 0%@0.4 micron of particle,

For the thin Chen @313 of AC feet per minute clock 10%@1 micron,

Filter face speed 70%@3 micron;

(aerodynamic size)

Dirt Zai He @50%AP increases-6 grams,

(10 * 10 * 15 " filter);

This class medium can be advantageously used in total arrangement thing of the present invention.But the working medium conduct, as apply the supporter of microfibre.In addition, this class material can be used as the top of microfibre medium or lower area to obtain having the whole compound of beneficial property.

4. the relevant result of pleating dielectric thickness; Handle.

In general, under the regular situation, for example rotary-type pleating equipment, the maximum ga(u)ge of medium can be easily pleating to about 0.060 inch thickness, typically thinner slightly basically media are preferred (0.040 inch often are 0.030 inch or thinner) for pleating system.Like this, basic consideration the factor of pleating medium be related general thickness.

In general, but with the medium life-saving of oil processing such as cellulose media.This part be since the medium collection of oil processing the carbonaceous particulate, it can not make up the dendroid aggregated particle and obstruct airflow, the carbonaceous particle suspension is in oil.United States Patent (USP) 5,238, the row that 474 (incorporate at these for reference) have disclosed with the oil processing medium puts.

In general, the inductor that flows on a large scale can be found the operating position that increases in the downstream of air filter.For example, in automobile and truck factory, the inductor that flows on a large scale is contained in the downstream of air cleaner sometimes.When the medium that is used for air cleaner relates to oil processing, oil processing itself can exert an influence to air cleaner, or its equipment of can making dirty.In case oil processing is arranged, medium has the tendency by more fine powders, owing to the inefficient filter life that prolongs.

In many occasions, comprise that the medium of the fine fiber layer that this paper discloses can advantageously be used for replacing the oil processing medium.Some examples as mentioned above.

But what generally must keep in mind is, for necessary medium is pleating, the gross thickness of medium should be 0.060 inch (0.15 centimetre) or still less, preferably 0.030 inch (0.076 centimetre) or still less.In order to realize this purpose, need the number of plies of restriction fine fibre, as much as possible the thickness of separation layer is reduced to reasonable level.Preferred thickness of isolating fiber is not more than about 0.003 inch (0.0076 centimetre) thickness, preferably is not more than about 0.0015 inch (0.0038 centimetre) thickness.

5. relate to the result of positive face velocity and gradient

V. non-gradient system

Some examples are indicated just as discussed below, when a pile or a regional fine fiber layer totally have equal percentage efficiency, under specific experimental condition, have gradient can be better than utilizing the situation of each fine fiber layer of equal efficiency between fine fiber layer.When even relating to equal overall composite efficient, each fine fiber layer that generally preferably constitutes compound has gradient, is put to greater efficiency (from top to the bottom) row by inefficient in compound.

People can consider whether also can keep observing this class result under on a large scale positive face velocity.More particularly, because positive face velocity increases significantly, people can infer, the dendroid aggregation of the particle that forms on the upper strata occurs in than under the low rate, because higher positive face velocity has bigger permeability, along with the dendroid in the formation of grit bump, can cause disintegrate (or formation of inhibition dendroid laying dust) of dendroid aggregation.Therefore, people can expect that to a certain extent, this medium uses under higher positive face velocity, can lose the advantage that adopts gradient layer (comparing with the non-gradient layer of employing) and form in the fine fibre compound.

6. some possible structures

The improvement of a. pleating chip architecture thing

The pleating medium of (from sheet) is used for various filtration device structure things.Normally used medium comprises: cellulose, glass fibre or synthetic polymeric fibers sheet; The polytetrafluoroethylene (PTFE) sheet of foaming; With fiber admixture sheet.The improved compound of putting comprising layers of fine fiber row of the present invention can be used with this class medium.

What make attention is, typically the fubril as the expanded polytetrafluoroethyl(ne sheet of filter media is of a size of the 0.1-0.3 micron, and permeability (fpm) is 2-70; LFES efficient＞80%, typically＞90% (typical DOP efficient is 80%-99.9999%).

Here, term " layers of fine fiber layer works or zone " or " MFFL works or zone " refer to fine fiber structure thing of the present invention.It generally includes by separation layer or matrix and arranges multilayer (the promptly two-layer at least) fine fiber layer that thing separates.Pointed as this paper principle, the fine fiber layer of use (identical or different LEFS efficient) can produce the overall preferred L FFL structure of better efficient.

The plain sheet of admissible conventional fibre has LEFS efficient greater than 15%; Permeability is greater than 10 feet per minute clocks, and general thickness is less than 0.020 inch.This is conventional pleated medium.(also can use replacement material discussed above certainly)

People can be applied to the FFFL works on the cellulose tablet (or various other sheet) to obtain obviously improved pleating medium according to the present invention.For example can consider that applying (or contiguous placement) overall LEFS efficient to the top of cellulose tablet is less than or equal to 60% MFFL works.This can easily form by using three layers of fine fibre, separates structure or support structure (base material) separates with as herein described.The orlop of fine fibre can directly be added on the cellulose tablet when needing.For example can be from showing the overall LEFS efficient about 60% of index in three layers of average LEFS efficient about 25%.

The employed every layer thickness of layer that separate is preferably less than 0.003 inch, more preferably less than 0.0015 inch.Therefore gross thickness is less than 0.060 inch basically, and it is easy to pleating.

This material or zone can easily be folded into engine and replace conventional cellulose tablet with filter.Because the load type that takes place in the MFFL of cellulose upstream works, it can be used to provide total filtration device structure of life-span prolongation.In the other method, it can be used to provide the life-span the same long with conventional (pleating cellulose) parts, but the littler filter component of size.Sometimes it can move into inside from the outside of motor vehicle, as is placed under the hood.

In total type of said structure thing, cellulose (or other sheet) medium in MFFL structure bottom provides some structural entity for whole system.Like this, the MFFL structure can be used for having the occasion of low relatively positive face velocity, but also can be used for having the situation of high relatively positive face velocity, for example is used for HVAC or cabin atmosphere filter.Certainly, it also can use with HEPA or ulpa filter.

B. the improved filter that relates to the depth media structure.

At United States Patent (USP) 5,082, the various air filter arrangements that relate to dark medium or each layer depth medium have been disclosed in 476,5,364,456,5,238,474 and 5,423,892 (incorporate at these for reference).In many occasions, place pleating medium (as, cellulose media) in the bottom of one or more dark areas of dielectric.In some occasion, for example, United States Patent (USP) 5,238, the 474 bottom pleating media that disclosed is characterized in that the pleating medium of oiliness, are typically the cellulose media with oil processing.As mentioned above, people are advantageously by using cellulose (or other sheet)/MFFL works combination of the present invention can advantageously avoid oil processing.This can save the space in certain occasion, avoids oily material that the upstream device such as extensive stream inductor is had a negative impact in addition.

Certainly, in MFFL works of the present invention can be used for also comprising that the row of oil medium puts.

C. the row as the cabin atmosphere filter puts

In general, cabin atmosphere filters, i.e. cabin atmosphere filtration for the vehicles relates to two aspects: remove peculiar smell; With remove particulate.There is the compound arrangement thing of MFFL works of the present invention can incorporate total system into to obtain the efficient of two aspect desired levels.Certainly, single fine fiber layer is arranged thing and also can be used with the combination of materials such as electret or carbon adsorbing medium.

As mentioned above, filtration typically needs chemical filter for peculiar smell.Can use such as activated carbon filter media,, reach this purpose as Hoechst Celanese AQF-375C.This class medium can be placed on, the top of MFFL works for example of the present invention.The MFFL works is quite effective for the particulate of removing in the cabin atmosphere filtration system.

In addition, people can incorporate " electret " works into total system.The medium that has promptly applied electric charge also can be used for cabin atmosphere filtration device structure thing.

Be typically, electret media has high starting efficiency, and it diminishes along with load up to beginning to form filter cake, and is invalid because it increases along with load, relatively very slow by the pressure differential growth of filter.Compare with electret, the MFFL works that this paper discloses generally has lower starting efficiency.When both combined, each just can realize their characteristics separately.If electret is placed on the top of MFFL material of the present invention, can obtain the high relatively advantage of electret starting efficiency.For example, the electret that can use relatively light (approaching) is obtaining desirable starting efficiency, but the formation of undesirable pressure differential that also slowed down.Can use the MFFL works so that to be provided total desirable efficient and long service life (formation of the pressure differential that slows down) in the bottom of electret.Certainly, this combination can be used for the occasion relevant with the medium of carbon load, also peculiar smell can be absorbed the required level that reaches.

Typical works is that for example a kind of compound comprises from top to bottom, electret/peculiar smell absorbent medium/MFFL works.

People can expect that the thickness of this class formation thing can be easily pleating with the techniques described herein.

D. the row for engine air filtration usefulness puts

Can predict, the technology of the present invention can be used for obviously improving the filtration system that engine is taken in air.This type systematic can be widely used in various combustion engines.They can be used for for example means of transport of automobile, light truck, haulage truck, heavy highway truck, Architectural Equipment, agricultural equipment, bus, unloading truck, refuse truck, and are used for the air filtering system of various miscellaneous equipments.For example.This technology can be used as the air shooting system of magnitude range at about 100 horsepowers to 300 horsepowers engine.

For this type systematic, relate to the medium of this paper exposing system, particularly pleating medium can be used to provide efficient height or the life-span is long or both have both benefit.In general, be 10%-90% based on efficient, be typically the single fine fiber layer of 10%-70%, can obtain efficient up to about 99% or higher total compound.Then medium can with other medium, pleating together as pleating paper or pleating synthetic medium, obtain required whole compound.Really, in some systems, also can apply dark dielectric structure in the top or the bottom of fine fibre.The front has been disclosed various.

E. be applied to the medium that is used for the Z filtration device structure

It is well-known that the various rows that are commonly referred to " Z-filter " works put.For example, referring to United States Patent (USP): 1,729,135,2,599,604,3,025,963,4,589,983,2,552,615,2,558,185,5,322,537,3,112,184,4,439,321,4,310,419,4,713,097,5,512,075 and 4,039,457; The United States Patent (USP) Shen 08/639,371 of awaiting the reply (1996,4,26 submit to) with common transfer; 08/638,453 (1996,4,26 submit to), 08/638,703 (1996,4,26 submit to) and 08/639,154 (1996,4,26 submit to).It is for reference that described 19 pieces of lists of references are incorporated this paper into.The fine fiber structure that can predict this paper announcement can be applied on this class medium.Promptly make this class formation that medium such as cellulose or synthetic medium wrinkles formation separate fine fiber layer (or MFFL structure) and go up (above typically being applied to) and improve usually by being applied to the present invention.Can provide and have the whole compound that more needs efficient/load character.Can predict, for example, this class row puts and can be used as the gas-turbine system in this type systematic, and engine is taken in air filtering system and relevant air filtration applications.

Experiment

In order to estimate medium of the present invention, now carry out various experiments.From experiment, can obviously see some advantage of using medium of the present invention.

The medium that is used to test

Various media are used for experiment.Used the wet medium of placing of 35%LEFS cellulose in the comparative experiments.Term herein " 35%LEFS " is illustrated in medium under the efficiency characteristics technical conditions, and to keep the efficient of 0.78 micro particles here be 35%.

In some experiments, used microfibre wherein to comprise the medium of glass fibre.In these cases, medium is included in the layer of glass on the sparse layer of porous polyester (Reemay 2011).In general, the diameter of glass microfiber is about 0.1-0.3 micron.Sparse layer of crude fibre or fibre substrate generally comprise the sparse layer of above-mentioned polyester, and commodity are called Reemay 2011.United States Patent (USP) 5,336,286 above-mentioned has disclosed the general technology of preparing of various glass fiber sample.Fiberglass media or compound are generally decided feature with LEFS%, and LEFS% represents to keep here according to the technology that this paper discloses the efficient of 0.78 micro particles.

Some samples that this paper discloses are called as " Ultra-Web ^Type " medium or DCI polymeric fiber material.These media generally include the sparse layer of coarse polyester (Reemay 2011), have applied the Ultra-Web of Donaldson company on it ^The microfibre of surface load medium.This microfibre size is generally about 0.1-0.5 micron, generally includes polymer.The typical feature of medium or compound represents that with LEFS% the implication of this term is identical with above-mentioned other application scenario.

Unless otherwise indicated, in all experiments, the crude fibre base material is Reemay 2011, compound, compound super 77 spray adhesives of 3M (Minnesota Mining and Manufacturing Company makes, Minnesota ,USA) stratification.Experiment 1

Tobacco smoke load

This experimental evaluation life-span of efficient medium less filter media in space but between the fiber of using the hole opened wide relatively and fibre structure of the present invention to improve with respect to making, have roughly the same starting efficiency by identical fine fibre.Use tobacco smoke that several reasons are arranged, at first, it can stop up the high efficiency particulate air filter of the routine with aperture rapidly.Tar in the smog is amorphous solid, and it can flow and stand the bigger capillary force from fine fibre.Capillary force makes the tobacco smoke residue cover fiber, and siphon enters the hole.The second, it is a common pollutant in air in the car hold, the room air etc.

The material of testing:

(a) the individual layer Ultra-Web  type fine fibre material that contains efficient submicron polymer fine fibre on Hovolin 7311 base materials.Hovolin 7311 is the Hollingsworth ﹠amp that contain polyester fiber; Vose model base material.

(b) the Ultra-Web  fine fibre of individual layer " medium " efficient (68.6%LEFS), it has the hole (interfibrous space) bigger than the individual layer high-efficiency polymer fine fibre in the clauses and subclauses (a).Substrate material is Hovolin 7311.

(c) 14 one deck compounds of the polymeric fine fibers on the Reemay 2011.The LEFS efficient of compound (always initial) is 99.6%, and the LEFS efficient of individual layer is about 28%.Between the fiber of this material fine fibre the space than clauses and subclauses (a) or the medium (b) big.Adopt Ultra-Web  technology that fine fibre is applied on the Reemay 2011 and prepare material.

The result:

1. under 6.8 feet per minute clocks (2.1 meters/minute), measure the load of the fluid resistance that causes 3 inchess of water(in H, represent with the radical of the cigarette of institute's burnup.

2. under every kind of situation, the area of load is 81 inches ²

Medium	Form the radical of the required cigarette of 3 inchess of water(in H	The initial LEFS efficient of compound	The final LEFS efficient of compound
Medium		The initial LEFS efficient of compound	The final LEFS efficient of compound	????(a)	????3	????99.3	Do not measure
????(b)	????16	????68.6	????34.1	????(a)	????3	????99.3	Do not measure
????(b)	????16	????68.6	????34.1	????(c)	????66	????99.6	????97.5

3. final LEFS efficient is considered to relevant with the character of pollutant compared with the LEFS efficient of beginning low (for medium (b) and (c)).(effect of the individual layer system that will note is more remarkable than multilayer system).The fluid that covers fiber increases the diameter of moistening fiber effectively.Also because increase falls in little bore closure and pressure, fluid and smog can turn to the long period to keep the bigger hole of opening-wide state.Less particle (0.78 micron) is not compared during load with medium and to be had littler collection tendency through macropore or bigger moistening fiber the time.

Conclusion:

Contrast medium (a) and (b) between difference, clearly show the compromise proposal between useful life and the efficient, this is compromise selects medium when using for certain, is typically available various selection.In this case, to (b), under the cost of 45 times of pollutants (according to initial efficient), can obtain to increase by 5 or 6 times useful life from medium (a).

Contrast medium (b) and (c) between difference, to (c), can obtain to increase by 4 times useful life from medium (b), the particle transmitance in the compound descends 78%, this increases to 99.6% by initial efficient from 68.6% and reflects.

Contrast medium (a) and (c) between difference, obtaining has increased by 22 times useful life, the particle transmitance of compound is constant substantially.

For selected efficient, make fine fiber layer from far away by using bigger fiber, just can significantly improve useful life.For the present invention, might in some systems, not only improve useful life but also raise the efficiency, or need not reduce another and improve one of them (reduce another improve one of them do not wish to take place) at least, yet, adopt conventional media typically to need compromise useful life and efficient.

Experiment 2

DOP efficient and load

Carrying out these tests is to be used for estimating high efficiency medium, the fibre structure that it adopts the hole to open wide relatively, with respect to make by same fine fibre have a roughly the same starting efficiency but between fiber for the less filter media in space, improved load (useful life).In other words, whether this research is to be used for estimating can keeping under the compound efficient that equates, by reducing the useful life that individual layer (component) efficient improves filter.DOP is a kind of oil, rather than amorphous solid, and as the tar that is comprised in the smoke from cigarette, role resembles the tar in the experiment 1 very much aspect closing closed pore, siphon and covering fine fibre.Yet the tester measurement Real time Efficiency and the pressure that are used for this experiment fall.

Be provided with:

Reference: military standard 282, ASTM D 2986.

The material of test:

(a) H ﹠amp; The efficient submicron polymer fine fibre of individual layer on V 7311 base materials, the LEFS efficient of combination is 99%.

(b) 8 layers compound: 7 layers of polymeric fine fibers and one deck Reemay2011 cover layer on Reemay 2011.Fine fibre is the type of being made by the Ultra-Web  technology of Donaldson.The initial LEFS efficient of (always) of compound is 97.5%, and the LEFS efficient of individual layer (Reemay 2011 has fine fibre) is 41%.Observe the bigger of the medium described in the gap ratio clauses and subclauses (a) between the fine fibre of this material.

(c) the 14-layer compound of the polymeric fine fibers on the Reemay 2011 (Ultra-Web  types of fibers).The total initial LEFS efficient of compound is 99%, and the LEFS efficient of individual layer (Reemay 2011 has fine fibre) is 28%.Spacing is designed to than clauses and subclauses (a) or the medium (b) big between the fiber of this material fine fibre.

The result:

(b) and medium (c) than by the spacing medium (being medium (a)) made of polymeric fine fibers more closely, demonstrate significant load advantage.

The medium explanation	The LEFS efficient (%) of compound	(inches of water(in H) falls in 100 milligrams of DOP final pressure afterwards	(inches of water(in H) falls in initial pressure	The increase that pressure falls (inches of water(in H)	Individual layer LEFS efficient (%)
The medium explanation	The LEFS efficient (%) of compound		(inches of water(in H) falls in initial pressure	The increase that pressure falls (inches of water(in H)	Individual layer LEFS efficient (%)	1 strata compound fine fibre	??99％	????1.95	????0.40	????1.55	????99％
8 strata compound fine fibres	??97.5％	????0.70	????0.62	????0.08	????40％	1 strata compound fine fibre	??99％	????1.95	????0.40	????1.55	????99％
8 strata compound fine fibres	??97.5％	????0.70	????0.62	????0.08	????40％	14 strata compound fine fibres	??99.0％	????0.70	????0.58	????0.12	????28％

All samples in this test has continued to observe the decline that efficient prolongs in time, and the decline of the LEFS efficient of being reported in the decline of efficient and the tobacco load test stabilization (testing 1) is similar.Think that the reason of decrease in efficiency is caused by the same phenomenon that is lived through in testing with tobacco smoke, in the conclusion of experiment 1, explain.

The medium explanation	The LEFS efficient (%) of compound	Initial DOP efficient (%, absolute value)	100 milligrams of DOP final DOP efficient (% absolute value) afterwards	The decline of DOP efficient (%, absolute value)	Individual layer LEFS efficient (%)
The medium explanation	The LEFS efficient (%) of compound	Initial DOP efficient (%, absolute value)		The decline of DOP efficient (%, absolute value)	Individual layer LEFS efficient (%)	1 strata compound fine fibre	??99％	????72	????62	????16	??99％
8 strata compound fine fibres	??97.5％	????59	????56	????3	??40％	1 strata compound fine fibre	??99％	????72	????62	????16	??99％
8 strata compound fine fibres	??97.5％	????59	????56	????3	??40％	14 strata compound fine fibres	??99.0％	????83	????70	????13	??28％

Annotate: the pressure that multilayer fine fiber structure has at interval stood to increase falls, and recruitment is 1/20 (medium (b)) and 1/13 (medium (c)) of fine fiber media (a) of the tight spacing of medium (a).

Conclusion:

The result of DOP load is consistent with tobacco smoke load result.Form the thin-crude fibre composite construction that replaces by the merging of inefficient layer, the individual layer fine fiber filter media that approximates compound combination layer efficient with efficient is compared, and can provide very big load (useful life) continuous benefit.

Experiment 3

NaCl load

Carry out this series of tests, estimate benefit by the following filter useful life that obtains: promptly by the high efficiency fine fiber media of the individual layer of substrate support, change the multilayer poor efficiency fine fibre become on the base material and compound LEFS efficient about equally.These tests are that with tobacco and the different of DOP load the salt particle that enters medium is the solids that disperse, and on-liquid or half amorphous state solid can produce caking thus, and efficient increase with load.Medium for all tests is all observed, and produces after the caking, and the gradient of the curve of load is very similar.Specifically, produce caking after, medium is just no longer tested or under fire.

A kind of tolerance of filter useful life is that it reaches predetermined pressure and falls the required time, and another kind is to measure to arrive the pollutant quality that is entered when predetermined pressure is fallen.Form this restriction of caking if predetermined final pressure falls far above beginning, what compare so is exactly the load of luming, rather than the comparison between the dielectric behavior.Here, the comparison of useful life is carried out in forming the general completed limit of caking.In following table, provided the operation that arrives 2 inchess of water(in H and 5 inchess of water(in H.Sample is to test under 10 feet per minute clocks.

Be provided with:

Medium carries out load on the load salt experimental bench (as shown in figure 25) of customization, the employing merchant sells assembly, constant high output atomizer 3076 types of TSI produce particle specifically, TSI 3054 type smog averagers and TSI Electrical Aerosol Analyzer (electric atomizing analyzer EAA) 3030 types, be used for particle is counted and grain size analysis, thereby record particle efficient when tested media load.Sub-micron salt is as pollutant, because use it than using traditional SAE silica dust, the easier difference of distinguishing the load between the different medium.

The material of test:

The compound LEFS efficient of medium is 40-45%, 60-65% and 75-80%.All compounds are all by polymeric fine fibers (Ultra-Web ^Types of fibers) on Reemay 2011 base materials, makes.For given composite sample, all layers are all made (promptly not having efficiency gradient in the compound of being tested in this serial experiment) by the medium that LEFS efficient equates in the sample.For example, if the LEFS efficient of compound is 50%, have 6 layers, so every layer (having fine fibre on Reemay 2011 base materials) all has 10.9% LEFS efficient.

The result:

The lower complex media of LEFS efficient of layer, its load performance (useful life) than comprise layer less and layer the higher complex media of LEFS efficient better.This tangible advantage of efficiency of selection and useful life is different with the application of many traditional sucroses independently.And in the operation of many employing conventional media, sacrifice efficient and improve useful life.

The compound LEFS efficient of 40-45%
The compound LEFS efficient of 40-45%				The number of plies	The LEFS efficient (%) of individual layer	Reach 5 inchess of water(in H time (minute)	Useful life (minute/minute) with respect to the reference medium
1 (with reference to medium)	????41	????230	????100％	The number of plies	The LEFS efficient (%) of individual layer	Reach 5 inchess of water(in H time (minute)
1 (with reference to medium)	????41	????230	????100％	????2	????21	????280	????122％
????3	????16	????350	????152％	????2	????21	????280	????122％
????3	????16	????350	????152％	????4	????12	????630	????273％
????5	????10	????680	????295％	????4	????12	????630	????273％

The compound LEFS efficient of 40-45%
The compound LEFS efficient of 40-45%				The number of plies	The LEFS efficient (%) of individual layer	Reach 2.0 inchess of water(in H time (minute)	Useful life (minute/minute) with respect to the reference medium
1 (with reference to medium)	????41	????110	????100％	The number of plies	The LEFS efficient (%) of individual layer	Reach 2.0 inchess of water(in H time (minute)
1 (with reference to medium)	????41	????110	????100％	????2	????21	????170	????154％
????3	????16	????250	????227％	????2	????21	????170	????154％
????3	????16	????250	????227％	????4	????12	????475	????432％
????5	????10	????525	????477％	????4	????12	????475	????432％

The compound LEFS efficient of 60-65%
The compound LEFS efficient of 60-65%				The number of plies	The LEFS efficient (%) of individual layer	Reach 5 inchess of water(in H time (minute)	Useful life (minute/minute) with respect to the reference medium
??2 ¹(with reference to medium)	41 (each layer)	????165	????100％	The number of plies	The LEFS efficient (%) of individual layer	Reach 5 inchess of water(in H time (minute)
??2 ¹(with reference to medium)	41 (each layer)	????165	????100％	????3	????28	????230	????139％
????4	????21	????290	????176％	????3	????28	????230	????139％
????4	????21	????290	????176％	????5	????18	????305	????185％
????7	????13	????510	????309％	????5	????18	????305	????185％
????7	????13	????510	????309％	????9	????10	????660	????400％

¹For this sample (and reference layer be denoted as have other two-layer samples), two-layer compound is as with reference to medium, is difficult to obtain because LEFS is the individual layer of 60-65%.Because it is two-layer that compound comprises, the efficient of each layer all is 41%, and gross efficiency is 1-[(1-0.41 just so) * (1-0.41)] or 65%.

The compound LEFS efficient of 60-65%
The compound LEFS efficient of 60-65%				The number of plies	The LEFS efficient (%) of individual layer	Reach 2.0 inchess of water(in H time (minute)	Useful life (minute/minute) with respect to the reference medium
2 (with reference to media)	41 (each layer)	????85	????100％	The number of plies	The LEFS efficient (%) of individual layer	Reach 2.0 inchess of water(in H time (minute)
2 (with reference to media)	41 (each layer)	????85	????100％	????3	????28	????125	????147％
????4	????21	????175	????205％	????3	????28	????125	????147％
????4	????21	????175	????205％	????5	????18	????210	????250％
????7	????13	????375	????440％	????5	????18	????210	????250％
????7	????13	????375	????440％	????9	????10	????540	????635％

The compound LEFS efficient of 70-80%
The compound LEFS efficient of 70-80%				The number of plies	The LEFS efficient (%) of individual layer	Reach 5 inchess of water(in H time (minute)	Useful life (minute/minute) with respect to the reference medium
3 (with reference to media)	40 (each layer)	????170	????100％	The number of plies	The LEFS efficient (%) of individual layer	Reach 5 inchess of water(in H time (minute)
3 (with reference to media)	40 (each layer)	????170	????100％	????4	????28	????230	????135％
????6	????20	????260	????150％	????4	????28	????230	????135％
????6	????20	????260	????150％	????7	????18	????340	????200％
????8	????16	????410	????240％	????7	????18	????340	????200％
????8	????16	????410	????240％	????9	????13	????540	????320％

The compound LEFS efficient of 70-80%
The compound LEFS efficient of 70-80%				The number of plies	The LEFS efficient (%) of individual layer	Reach 2.0 inchess of water(in H time (minute)	Useful life (minute/minute) with respect to the reference medium
??3 ²(with reference to medium)	40 (each layer)	????80	????100％	The number of plies	The LEFS efficient (%) of individual layer	Reach 2.0 inchess of water(in H time (minute)
??3 ²(with reference to medium)	40 (each layer)	????80	????100％	????4	????30	????125	????156％
????6	????20	????170	????213％	????4	????30	????125	????156％
????6	????20	????170	????213％	????7	????18	????230	????287％
????8	????16	????280	????350％	????7	????18	????230	????287％
????8	????16	????280	????350％	????9	????13	????400	????500％

Conclusion:

From this result of experiment, can know and find out, might select the efficient and the load (useful life) of medium independently, and for typical conventional media and selected initial LEFS efficient, the scope of corresponding load salt useful life can be limited in the scope that is lower than 2: 1.This experiment shows can be by increasing spacing between the fine fibre, reduce average layer efficient and increasing the number of layer, can make one 5 of the useful life increase of load sub-micron salt or 6 the factor.

Experiment 4

The load of the salt under the 150 feet per minute clocks

Be provided with:

Sample area: 25 inches ²(the square sheet on plane) adopts the testboard (signal 14) of customization and the Collison atomizer of customization, TSI 3054 averagers.

The material of test:

1 is used for the conventional wet-laying cellulose that engine air filters, and its initial LEFS efficient is 35-38%.Typically under the positive face velocity of 8-10 feet per minute clock, operate.

23 layers of compound being made by the hand papermaking glass microfiber of wet-laying on Reemay 2011, the fiber size scope is: sub-micron is to about 3 microns.

Total LEFS efficient 32% of compound

The efficient 12% of individual layer (each layer)

Used glass fibre is Schuler #106.

The result:

Medium	Thickness (inch)	Initial LEFS efficient (%)	(inches of water(in H) falls in the initial pressure under the 150 feet per minute clocks	The increase that pressure falls (inches of water(in H)	150 feet per minute clocks be issued to the pressure that increases fall the required time (minute)
Medium	Thickness (inch)	Initial LEFS efficient (%)		The increase that pressure falls (inches of water(in H)		The surface load cellulose media	??0.013- ??0.015	??35-38	????6.8	????5.8	????13
3 layers of compound (glass fibre does not have gradient)	??0.026- ??0.028	????32	????0.5	????3.5	????75	The surface load cellulose media	??0.013- ??0.015	??35-38	????6.8	????5.8	????13

Conclusion:

Folding 3 layers of complex media, comprise the sparse thing that has the net of making by glass fine fibre (diameter is one 3 microns of sub-micron), it is compared with the collapsible cellulose media of the approximately equalised surface load of initial LEFS efficient, shows the permeability (13 times) that enlarges markedly and the useful life (＞5 times) of load sub-micron salt.The test speed of 150 feet per minute clocks is selected arbitrarily, is intended to illustrate the ability of medium.This cellulose media that does not mean that the hint engine air is operated under the positive face velocity of 150 feet per minute clocks usually.

Experiment 5

The embodiment of non-gradient and gradient

This experiment is intended to the load result of the identical non-gradient media of the number of plies that load result that more initial LEFS efficient is about 65% gradient embodiment of the present invention and LEFS efficient equates.

Be provided with:

Identical with the experiment of the load salt of above-mentioned experiment 3.

The material of test:

1 polymer sub-micron fiber (Ultra-Web ^Types of fibers) be deposited on the Reemay 2011, adopt 3MSuper 77 to make it lamination by hand, make non-gradient media, it is two-layer that the LEFS efficient of each layer all is approximately equal in the compound other in this medium.The LEFS efficient of individual layer is about 24%.

2 gradient media are by the polymer sub-micron fiber (Ultra-Web that is deposited on the Reemay 2011 ^Types of fibers) make, the LEFS efficient of its subsequent layer is bigger than anterior layer.Selected gradient is selected arbitrarily, equates under the situation in total LEFS efficient, and for 3 layers gradient compound, whether the different choice of layer can obtain the benefit of extra useful life, still unknowable.Here under the situation, from the upper strata to the lower floor, the LEFS efficient of each layer is about 10%, 20% and 40%.They are also with 3M Super 77 manual being formed by stacking.

The result:

The result as described in Figure 22.

Observation report and conclusion

Gradient type of the present invention has utilized available dielectric capacity better than the equivalent (thickness, permeability and LEFS efficient) of non-gradient.With respect to non-gradient media, the load of the submicron particle of gradient sample has increased 66%.Spacing between this available once more fine fibre is explained.The non-gradient media structure that capacity and efficient equate with gradient media, because caking is formed on the last aspect of non-gradient media, it does not more likely use the load potential towards the fiber of medium subsurface.Caking forms sooner than functionally gradient material (FGM) on non-gradient media.This is because the average distance upstream layer lower than the efficient of gradient media between the fine fibre of non-gradient media littler.As the index of weighing fiber spacing, the LEFS efficient of the ground floor that non-gradient row puts is 24% with LEFS efficient, and the ground floor efficient of gradient-structure is 10%.Thus, the gradient media structure can more effectively be utilized all available dielectric capacities than non-gradient equivalent.

Experiment 6

Contrast between glass fibre and the polymer sub-micron fiber

This test is the use submicron polymer (Ultra-Web of test in experiment 5 relatively ^Types of fibers) gradient media of fine fibre and glass fibre system.

Polymer fiber is about 0.4 micron, and fiber size changes less.Glass fibre is a Schuller fiber 106, is about the 0.2-3.0 micron.Also tested LEFS efficient and be 40% the glass and the single-layer medium of polymer fiber pattern.

Be provided with:

See the load of the salt of experiment 3,10 feet per minute clocks.

The material of test:

1. from the polymeric fine fibers gradient media of testing 5.

2. at the sub-micron glass fibre gradient type of testing the gradient media of test in 5.Select the sub-micron glass fibre, make it suitable with the average-size of polymer fiber, but near the distribution difference mean value.8 * 8 inches hand papermakings of employing standard form the hand papermaking that device prepares wet-laying.Glass fibre is positioned on the Reemay 2011 that is supported by thin plastic wire, and the fiber that drains behind the moisture content is often collected by this Netcom from slurry.

3.LEFS efficient is 40% single polymer layer fine fiber media.

4.LEFS efficient is 40% single-glass fine fiber media (Schuller #106).

The result:

Under 5.0 inchess of water(in H, the load difference of gradient is about 5%, and the load difference of individual layer 40%LEFS efficient sample is about 10%.The in good time speed of medium is very similar to single-layer medium.For gradient media, increasing of glass fiber sample efficient comes sooner than polymer fiber.Its reason just obtains part in time and understands afterwards when finding that about glass fibre below 3 microns is contained in the glass fibre raw material that is used for making the hand papermaking sample.This just finds when bat SEMS photo is analyzed hole dimension.This result of experiment is shown in the figure line among Figure 23 and the 23A.

In Figure 23, the performance of single polymer layer fiber (40%LEFS) with single-layer glass fiber (40%LEFS) compared in mapping.

In Figure 23 A, the performance of 3 layers of polymer fibres gradient samples (60%LEFS) with 3 layers of glass fibre gradient sample (60%LEFS) compared in mapping.Be also noted that for every type (polymer or glass), it is about 70% that the medium useful life of gradient system form improves, and permeability descends about 33%.This shows when using optimization technique of the present invention, needn't sacrifice efficient and improve useful life.

Conclusion:

The load performance of the medium of gradient profile is better than non-gradient system.

Before forming caking, the behavior of glass and polymer fiber is similar, wideer than polymer fiber although the fiber size of glass fibre distributes.Suppose that fiber size is different with distribution, and this does not wish to take place.Difference after caking forms on the curve of load slope it be not immediately clear.

Experiment 7

The observation report of various samples

Figure 12-the 21st, the electron scanning micrograph of various media (SEMs).By observing shown various medium repeatedly, just can understand principle of the present invention.

At first see Figure 12.Figure 12 amplifies 100 times electron scanning micrograph, and it has shown the polymer fiber medium of conventional air lay, and especially Kem Wove 8643.It is consistent can be observed fiber size.This is the material at 1.5 dawn.Its LEFS efficient is 3%, and thickness is about 0.3 inch.Its Unit Weight is about 73 pounds/3000 feet ², the solid content of volume is 1.1%, permeability is 400 feet per minute clocks.

Figure 13 is conventional air lay fiberglass media, has amplified 100 times.Specific medium is AF18, available from Schuller.Visible once more fiber size is consistent.Its LEFS efficient is 12%, thickness is that 0.18 inch, Unit Weight are 60 pounds/3000 feet ², the solid content of volume is 0.9%, permeability is 230 feet per minute clocks.It is 45% that the ASHRAE of material leads, and fiber size is about 4.5 microns.

Figure 14 and 15 shows conventional two-phase medium, amplifies 500 times.Two-phase all is a glass fibre.Medium on two photos is Hollingsworth ﹠amp; Vose HF343.Figure 14 is the anterior layer photo, wherein has than crude fibre to exist.Figure 15 is a back layer photo, can see fine fibre and coarse-fibred mixture.HF343 is the fiberglass media of wet-laying.The anterior layer of medium (phase 1) has that open wide relatively, big, thick, self-supporting fiber, is used for catching and storing thick pollutant.The back layer (phase 2) of medium is made by fine fibre and coarse-fibred composition.Fine fibre provides than the higher efficient of crude fibre in 1 mutually but lower load capacity.The ASHRAE of medium leads and is about 60-65%.The LEFS efficient of HF343 is 23%, and thickness is 0.02 inch, and Unit Weight is 50 pounds/3000 feet ², the solid content of volume is 7.1%, permeability is about 135 feet per minute clocks.

Generally speaking, the volume solid content of fine fiber layer of the present invention is difficult to direct or indirect measurement, and is when LEFS efficient is lower than about 15-20%, just more difficult.Main difficulty is to estimate that the local approach of fine fiber layer is to thickness.Constitute the thin and coarse-fibred composition that the present invention row puts for typically being used for, fine fibre forms unlimited porous " surface ".Its surperficial pattern is similar to the cobweb of putting on a suit of armour on supporting construction.The surface configuration of microfibre base material stems from the hole of fibre structure and following (supporting construction) thereof, thereby base material has many peaks, paddy, ridge and groove.The gauge that is used for estimating solid content be not from the peak to the size of paddy, but the thickness of the net/layer of peak, paddy or locally flat location.This geometry pattern is also not obvious in the SEM photo, but is observed under 10-40 multiplication factor doubly by stereoscope, just seems obviously.The material solid content of being reported of the present invention is estimated, stems from the estimation to fine fiber layer normal direction local thickness.

Figure 16 is a complex media of the present invention.This medium contains the Schuller glass fibre 106 that is deposited on the Reemay 2011.The diameter of fine fibre is in from sub-micron to about 3 microns scope.The amount of the fiber 106 of deposition should be enough to guarantee that formed layer has 40% LEFS efficient.In the drawings, can easily see the very thin fiber that constitutes fine fiber layer.Below, in some position, can see thicker fiber.

The material of Figure 16 is made by the fine fibre material of the hand papermaking of wet-laying, and book is described as described above, and the fine fibre material is deposited on Reemay 2011 base materials.In this medium, the numerical value of the ratio of expression base material crude fibre diameter and fine fibre diameter is far longer than the value in the medium shown in Figure 14 and 15.From the permeability of compound, deduct the contribution of base material, estimate the permeability of fine fiber layer.The sample that permeability is high for efficient is low is necessary to build up multilayer, obtains the numerical value that can measure, calculates average permeability.

For such material, when amplifying 1000 times of measurements, average area solid content is about 52%.Permeability is about 190 feet per minute clocks, and the volume solid content is about 10%, and Unit Weight is 1.5 pounds/3000 feet ², thickness is 10 microns.

Figure 17 is another complex media of the present invention.Shown medium has amplified 100 times among Figure 17.Medium comprises DCI (Donaldson Company Inc.) polymeric fine fibers, and it is positioned on the thick base material that comprises Reemay 2011.The DCI polymeric fine fibers is basis and the Ultra-Web that is used for making Donaldson usually ^The technology that the technology of the polymeric fine fibers that product is used is identical, the technology that belongs to business secret are made.The diameter of fine fibre is a sub-micron.

Figure 18 is another complex media of the present invention.In Figure 18, shown medium amplifies 100 times.Medium comprises the Schuller glass fibre 106 that is deposited on the Reemay 2011.The glass fibre quantity that exists should be enough to provide 12% efficient (LEFS%).The Unit Weight of fine fiber layer is about 0.5 pound/3000 feet ², permeability is about 600 feet per minute clocks.In microphoto, crude fibre and fine fibre both can easily see.When amplifying 1000 times of estimations, the average area solid content of material is about 33%.

Figure 19 is another complex media of the present invention.It comprises and is deposited on DCI polymeric fine fibers on the Reemay 2011, amplifies 100 times and illustrates.Shown medium has the efficient of 12%LEFS.Can easily see fine fiber webs once more, it be positioned at following crude fibre supporter above.Amplify 500 times when estimating, the average area solid content that observes this material is 22%.

Figure 20 is the microphoto of material shown in Figure 19, amplifies 500 times and illustrates.Can easily see the top very thin fleece of crude fibre supporter below.

After Figure 21 is material load NaCl shown in Figure 19, amplify 1000 times photo.Can easily see captive salt particle on fine fibre very on the photo.

In Figure 24, shown the medium of 1000 times of the amplifications with 18%LEFS of load NaCl.Can see that the NaCl particle mainly is trapped on the fine fibre.Dielectric material among Figure 24 is the DCI polymeric fine fibers on the Reemay 2011 thick base materials.

In the row of the present invention shown in Figure 16-20 puts, roughly can find out the feature that is positioned at the very fine fibre on the thick base material.This situation has been ignored efficient or has been used for forming the predetermined substance of fine fibre.In Figure 21, can easily observe and realize load necessary operations on the fine fibre.

Further option

In some cases, row of the present invention as can be seen puts and can be used to relate to the environment that filters fluid, and described fluid contains the incompatible composition of fibrous material chemistry with some type.For example, some air-flows can carry the chemicals that damage polymeric material but do not damage glass.If this situation is arranged, preferably make filtering material by such material: its opposing in predetermined environment for use damages.

Further, it can also be seen that, in some cases, also can require the present invention amplified by a certain percentage and use.This application is exactly that wherein " fine fibre " in the compound is bigger, and crude fibre is bigger.That is, the dimensional ratios between fine fibre and the crude fibre can remain in the scope of common regulation, yet every kind size and thickness in fact can be bigger than preferable range described here.For example, every kind of diameter may be than the big 5-10 that stipulates here doubly.This structure is available, for example at the inner agglomerate that forms of deep layer medium, perhaps forms and comprises fibrillose and the effective relatively deep layer medium of resistivity easily takes place to have when subsiding with load under relating to the unique situation of filtering suitable macroparticle.This is unpredictable: this structure will be for will being preferred or desired under most of industry that typically run into and/or the engine conditions.

Claims

1. Filter structure, which includes:

(a) a region of filter media comprising at least two layers of spaced apart fine fiber media comprising fibers having a diameter of no greater than about 8 microns;

(i) each layer of fine fiber media has: an average fiber diameter of not more than about 5 microns, and an intrinsic efficiency of not more than about 90% for 0.78 micron particles;

(ii) Each of the at least two layers of fine fiber media is separated from an adjacent layer of fine fiber media by a distance of not more than 254 microns.

2. Filter structure, which includes:

(i) each of said at least two layers of fine fiber media has an average fiber diameter of not more than about 5 microns, each of said at least two layers of fine fibers has a basis weight of not more than about 45.0 g/m A spacer structure of ² is spaced from adjacent thin fiber layers.

3. A filter structure as claimed in any one of claims 1 and 2, wherein:

(a) Each layer of fine fibers within the filter media region has an intrinsic efficiency of not more than about 70% for 0.78 micron particles.

4. A filter structure as claimed in any one of claims 1-3, wherein:

(a) The filter media region is a pleated filter media region.

5. The filter structure of claim 4, wherein:

(a) said pleated filter media regions have a total thickness of no more than about 0.15 cm.

6. A filter structure as claimed in any one of claims 4 and 5, wherein:

(a) The pleated filter media region comprises at least one layer of pleated material selected from the group consisting of: cellulose, glass, synthetic fibers, fiber blends, and expanded polytetrafluoroethylene.

7. The filter structure of any one of claims 1-6, comprising:

(a) A fibrous depth media region above said filter media region.

8. The filter structure of claim 7, wherein:

(a) The fiber deep medium region includes a density gradient deep medium region.

9. A filter structure as claimed in any one of claims 1 to 8, wherein:

(a) The filter media zone described is located in an engine intake filter for use with an engine of at least 100 horsepower.

10. The filter structure of claim 9, wherein:

(a) The engine air intake filter includes first and second end caps with the filter media region extending therebetween.

11. The filter structure of any one of claims 1-10, wherein:

(a) said at least two layers of fine fiber media include an uppermost layer of fine fiber media;

(i) said uppermost layer of fine fiber media has a thickness of not more than about 5 times the average diameter of the fine fibers;

(b) said filter media region comprising a region of permeable coarse fibrous material between said uppermost layer of fine fiber media and an underlying adjacent layer of fine fiber media;

(i) said region permeable to coarse fibrous material:

(A) comprise fibers having a diameter of at least 10 microns; and

(B) Has an efficiency of not more than 10% for 0.78 micron particles when evaluated out of structure.

12. The filter structure of claim 11 comprising:

(a) at least two layers of fine fiber media other than the uppermost layer of fine fiber media;

(i) each of said at least two layers of fine fiber media other than said uppermost layer contains fibers having an average diameter of no greater than about 6 microns.

13. The filter structure of any one of claims 1-12, wherein:

(a) The thickness of each layer of fine fiber media is not more than about 20 microns.

14. The filter structure of claim 1 comprising:

(a) a region in which at least one chemisorption medium is present.

15. The filter structure of any one of claims 1-14, comprising:

(a) At least one of the regions has an electrostatically charged medium.

16. The filter structure of claim 4, wherein:

(a) The pleated filter media region comprises a multilayer composite having a thickness not greater than about 0.15 cm, a pleat depth of at least 0.6 cm, and having more than one pleat per 2.54 cm.

17. The filter structure of claim 16, wherein:

(a) said at least two layers of fine fiber media comprising first and second layers;

(i) said first layer of fine fiber media comprising an uppermost layer of fine fiber media is located within said pleated media, said first layer of fine fiber media comprising media having an average fiber diameter of no greater than about 3 microns;

(ii) the thickness of the first layer of fine fiber medium is not more than 15 microns;

(iii) said first layer of fine fiber media itself has a permeability of at least about 90 meters per minute and an efficiency of not more than about 60% for 0.78 micron monodisperse polystyrene latex spheres;

(iv) said second layer of fine fiber media is positioned below said first layer of fine fiber media, said second layer of fine fiber media comprising media having an average fiber diameter of no greater than about 3 microns;

(v) said second layer of fine fiber media has a thickness of no more than 15 microns;

(vi) said second layer of fine fiber media is not more than about 60% efficient for 0.78 micron monodisperse polystyrene latex pellets; and

(vii) said second layer of fine fiber media is separated from said first layer of fine fibers by a distance of not more than 254 microns.

18. The filter structure of claim 17, wherein:

(a) The second layer of fine fiber media is more efficient for 0.78 micron monodisperse polystyrene latex pellets than the first layer of fine fiber media.

19. The filter structure of claim 18, wherein:

(a) The pleated media region includes an upper layer of coarse fiber material adjacent to the top of the first layer of fine fiber media, the upper layer of coarse fiber material comprising a nonwoven substrate of substantially continuous fibers, the average fiber At least 12 microns in diameter;

(i) The upper layer of coarse fibrous material is not more than 10% efficient on its own for 0.78 micron monodisperse polystyrene latex spheres.

20. The filter structure of claim 19, wherein:

(a) The pleated filter media region includes a cylindrical pleated filter.

21. The filter structure of claim 19, wherein:

(a) The pleated filter media region comprises a plate filter.

22. The filter structure of claim 16, wherein:

(a) The pleated filter media includes a third layer of fine fiber media positioned below the second layer of fine fiber media.

23. A method for filtering an air system for selectively removing pollutant particles therein, said method comprising the steps of:

(a) directing a contaminated gas stream carrying particles through a filter structure comprising at least a first layer and a second layer of spaced apart layers of fine fiber media;

(i) each layer of fine-fiber media is separated from adjacent layers of fine-fiber media by a distance not exceeding 254 microns; and

(ii) Each layer of fine fiber media has an average fiber diameter of not more than about 5 microns.

24. The method of claim 23, wherein:

(a) The directing step includes directing the intake air flow of the engine.

25. A method of filtering an air stream for selectively removing contaminant particles therein, said method comprising the steps of:

(a) directing a particulate-laden contaminated gas stream through a filter structure comprising at least a first layer and a second layer of spaced apart layers of fine fiber media;

(i) each layer of fine fiber media is separated from adjacent layers of fine fiber media by a spacer structure having a basis weight not exceeding about 45.0 g/ ^m2 ; and