JPH0350567B2 - - Google Patents

Description

Claim 1: The air or gas stream has at least one filter layer 2 which is impinged and permeated by the air or gas stream passing through the filter device in order to separate adulterated foreign matter from the air or gas stream. In the filter device to be purified, a plurality of flexible strips 8 of fibrous or non-woven material are provided in close proximity to the front side of the filter layer 2, which is first struck by the incoming gas, the strips 8 can be moved against the front side of said filter layer 2 and can be applied to the advancing gas stream in order to strike the filter layer 2 or perform another mechanical action to prevent the filter layer 2 from clogging prematurely. The strip material 8 is then moved automatically.
A filter device for the purification of air or gas, characterized in that it captures and separates adulterated foreign substances from the gas stream in order to pre-filter the gas stream before it reaches the filter layer 2.

2. A filter device according to claim 1, characterized in that the strip material contains fibers, such as polyester fibers, which impart electrostatic properties to the strip material.

3 constructed in the form of a cylindrical tube assembly of at least one fine filter tube 1 and at least one coarse filter tube 2 arranged in this fine filter tube 1 and accommodating said movable element or strip material 8; A central cavity 7 is defined, one end of the tube assembly is closed and the other end is open, so that said cavity 7
Each strip of material 8 serves as an inlet opening 5 for the gas flowing into the coarse filter tube 2 and out of the coarse filter tube 2 into the fine filter tube 1, with each strip 8 forming an inlet opening 5 in the tube assembly.
3. The filter device according to claim 1 or 2, wherein the filter device is fixed at only one end in the range of 1 and 2, and is movable over the entire length excluding the fixed end.

4. The number of strips 8 is such that the cavities 7 in the tube assembly are almost completely filled with strips, and the strips are in contact with each other, but
4. A filter according to claim 3, characterized in that the strips are partially separated from each other by small irregular cavities to form bundles of strips of material randomly oriented within the cavity 7. Device.

5 A strip of material is cut from the fabric by a number of substantially parallel cuts 10, the length of the cuts 10 being shorter than the size of the fabric in the cutting direction, leaving an uncut portion 11 of the fabric; Claim 4, characterized in that 11 holds the strip material together as one unit.
The filter device described in Section.

6 A fiber mass is provided in the space between the coarse filter layer 2 and the fine filter layer 1 to trap fine foreign matter from the gas flow before the gas flow passes through the coarse filter layer 2 and reaches the fine filter layer 1. A filter device according to any one of claims 3 to 5, characterized in that:

7. The filter according to any one of claims 3 to 6, characterized in that the space 13 between the coarse filter layer 2 and the fine filter layer 1 contains an absorbent such as activated carbon. filter device.

8 that said space 13 houses at least one ring 14 of an elastically extensible material, e.g. A filter device according to claim 7.

TECHNICAL FIELD The present invention relates to an air or gas stream having at least one filter layer when impinged and permeated by an air or gas stream passing through a filter device for separating adulterated foreign matter from an air or gas stream. The present invention relates to a filter device for purifying gas.

BACKGROUND OF THE INVENTION Swedish Patent Application No. 8207099-6 describes a filter device in the form of an integral bag consisting of a coarse filter bag and a fine or micro filter bag surrounding the coarse filter bag. The main advantage of this filter system is that the coarse and fine filters can be disassembled and processed as a single unit. However, it has been found difficult to provide the coarse filter bag or layer with a fibrous structure that will trap and separate only the very coarse particles in the air stream, while allowing the fine particles to pass through the fine filter layer.
For this reason, both coarse and fine foreign matter aggregate inside and outside the coarse filter layer, causing the coarse filter layer to become clogged quickly. As a result, the life of the entire filter device is short.

DISCLOSURE OF THE INVENTION The object of the present invention is to eliminate the above-mentioned drawbacks and to provide a filter device with a long service life.

According to the invention, this object is achieved by providing a plurality of flexible strips of fibrous or non-woven material in close proximity to the front side of the filter layer, which is first struck by the incoming gas; can be moved against the front side of the filter layer and automatically actuated by the advancing gas stream to strike the filter layer or perform another mechanical action to prevent premature clogging of the filter layer. This is achieved by moving the strip material itself to trap and separate any contaminants from the gas stream in order to pre-filter the gas stream before it reaches the filter layer. .

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a filter device according to the present invention, FIG. 2 is a sectional view taken along the line - in FIG. 1, FIG. 3 is a perspective view showing a method for manufacturing a strip material used in the filter device, 4 is a longitudinal cross-sectional view of a different embodiment of the filter device according to the present invention, and FIG. 5 is a cross-sectional view taken along the - line in FIG. 4.

BEST MODE FOR CARRYING OUT THE INVENTION The filter device shown in FIGS. 1 and 2 is
It is in the form of a cylindrical tube or tube assembly consisting of an outer, tubular, fine filter layer 1 and a coarse filter layer 2, which is likewise substantially tubular. The coarse filter layer 2 is located within the fine filter layer 1 and, in the embodiment shown, is folded in order to increase the filtering area. One end of the tube assembly thus formed is closed by a flat disc 3 of a suitably rigid and inexpensive material, such as cardboard or corrugated paper. At the other end of the tube assembly there is provided a flat annular plate 4 with a central opening 5 forming the inlet of the filter arrangement. In practice, this plate 4 preferably consists of the same material as plate 3. The plates 3 and 4 are coated with the filter layers 1 and 4 in a suitable manner.
2, the filter layers 1, 2 are preferably fixed to the plates 3, 4 by gluing, but optionally the edges of the plates 3, 4 and the outwardly folded edges of the outer filter layer 1 are An additional edge ring 6 is provided which surrounds and holds it together.

As is clear from the drawings, a cavity 7 is defined by the coarse filter layer 2 and the bottom plate 3. According to the invention, this cavity 7 accommodates a plurality of elongated flexible strips 8. These strips 8 are automatically moved by air entering the cavity 7 and exiting through the two filter layers 1,2. These strips 8 are made of fibrous or non-woven material, ie cellulose fibres. Actually a thin strip of material, i.e. 0.05~0.25
It is advantageous to use strip materials which are in the range of mm and have a relatively wide mesh fiber network structure, yet have a high tear resistance and a sufficient breaking length. The fiber material used can thus consist of fibers from linen, juute, hemp, cotton or linters, in addition to fibers from chemical pulp of pine or pine. Based on the special characteristics, the strip material is made of different kinds of man-made fibers that give the strip material electrostatic properties in order to enhance the dust collection properties of the strip material and at the same time make the strip material highly repellent to each other. , for example, contains a suitable amount of polyester fibers.

As can be seen in Figure 1, the number of strips is such that the cavity 7 of the tube assembly is almost completely filled with strips, and the strips are oriented randomly within the cavity 7. To form a bundle of strips of material, they are in contact with each other but separated by small, partially irregular cavities. In particular, the strip material is so thin or fine that it at least partially fills the spaces between the folds of the coarse filter layer 2.

An advantageous method of manufacturing the above-mentioned strip material will now be explained with reference to FIG.

Based on this method, a fabric of a suitable type of material is wrapped several times onto a cylindrical core 9, and then a number of approximately parallel cuts 10 are made in the superimposed layers of this fabric. This cut 10 is
The length is slightly shorter than the size of the fabric in the longitudinal direction of the core 9. Therefore, an uncut portion 11 is left between one end of the fabric and each cut 10;
This uncut portion 11 holds the various strips of material together as an integral unit. This unit is then placed in the cavity 7 of the filter device,
The uncut portion 11 is folded over the upper edge of the coarse filter layer 2 and adhered between the filter layer 2 and the annular plate 4. This means that each strip of material is fixed at only one end in the area of the inlet opening 5 of the filter arrangement, and the remaining part of the strip of material depends freely and movably into the cavity 7. There is. does the material of the strip material have a tendency to curl or twist so that the portion of the strip material depending within the cavity 7 does not follow a predetermined pattern but forms a deliberately disordered shape; It is given.

In the particular embodiment shown in FIGS. 1 and 2, the coarse filter layer 2 has an inherent stiffness that at least allows the coarse filter layer to be bent only to form a support or a rigid body. It is assumed that In reality, this coarse filter layer 2 is made of paper with a thickness of 0.5 to 2.0 mm. In addition to the normal cellulose fibers, it contains one or more man-made fibers, ie man-made fibers which give the filter layer electrostatic properties. Although the fine filter layer 1 also has a certain inherent stiffness, it need not be the same as that of the filter layer 2 described above. However, it is important that the filter layer 1 has a very dense structure in order to act as a micro or fine filter that can capture and restrict much finer foreign matter than the coarse foreign matter captured by the filter layer 2. It is.

Method of operating a filter device according to the invention As the air stream entering through the inlet opening 5 and being sucked or forced out of the filter layers 1, 2 passes through the cavity 7, the strip of material 8 is moved. In particular, this movement is such that each strip of material 8 is gently flapping under the mechanical action of the adjacent strip of material, such that the strip of material in the immediate vicinity of the front side of the filter layer 2 facing the air flow is It means to hit or scrape the front of the. As a result, fine foreign matter, coarse foreign matter, or dirt in the air flow does not adhere to the surface of the filter layer, and the strip material allows only coarse foreign matter to be captured by the filter layer 2, and fine foreign matter to be captured by the fine filter layer. 1
It continues to be moved so that it can pass up to. This effect was observed in an experiment in which the filter device described above was compared with a corresponding filter device without strip material, in which the filter device equipped with strip material was 10 times more efficient than the filter device without such strip material. It has been confirmed that it has a lifespan that is twice as long. Another reason for this increased lifespan is that the bundle of strips, in addition to the above-mentioned self-cleaning action, has a distributing and retarding action. The strip thus slows down the airflow entering through the inlet opening 5 and divides this airflow into a number of small branches that gently proceed through the labyrinth and small cavities defined by the strip. while these sub-flows are distributed substantially uniformly over the entire length of the filter device or over the entire surface of the coarse filter layer 2 exposed to the air flow. This distribution of the air flow into a number of sub-streams also has a protective effect so that extremely coarse or hard foreign objects carried by the main stream of air never come into direct contact with the coarse filter layer 2. It is believed that as a result such foreign matter is trapped in the strip material, so that the strip material acts as a prefilter for the coarse filter layer 2. Furthermore, the strip material 8 itself is capable of trapping most of the solid components entrained in the air stream.
An additional advantage derived from the use of the strip material according to the invention, which is of great value in practice, is that the strip material allows solid foreign bodies to enter the cavities but prevents them from escaping. Forming a similar device, the object is that foreign bodies separated within the cavity 7 are essentially completely confined within the cavity. Experiments have shown that even if the filter device is turned upside down with the inlet opening 5 on the downstream side, very little dust escapes from the cavity. This dust restraint effect is especially effective when the strip material 8
If the strip is made of a material with electrostatic properties, the rubbing or friction that occurs between the strip materials can cause the dust particles to have a high electrostatic charge that is attracted to and adheres to the surface of the strip material. ing.

FIGS. 4 and 5 show a coarse filter layer 2' and a fine filter layer 1' as a developed embodiment.
In addition to the filter arrangement (in the form of a tube), a filter arrangement is shown which has a further filter layer, namely a tube 12 arranged in direct connection with the coarse filter tube 2'. Between the filter tube 1' and the filter tubes 2', 12 there is in fact between 5 and 25% of the total diameter of the filter device, preferably about
An annular gap 13 having a width of 10% is formed. This void 13 contains an absorbent that substantially fills the void. In practice, this absorbent is a granular and/or special material such as activated carbon or the material sold under the trade name "PURAFIL".

Although the absorbent in the cavity 13 completely fills the annular space during the manufacture of the filter device, the absorbent constantly tends to become clogged due to shocks and vibrations during transport from the factory to the point of use. In order to prevent such absorbent blockages from forming unfilled spaces, at least one layer of elastically extensible material, such as foam rubber, is placed in the cavity 13.
Two rings 14 are provided. this ring 1
4 is compressed during the manufacture of the filter device, and as the volume of the absorbent decreases due to vibration, the ring 1
4 correspondingly expands and fills the empty space with absorbent so that air or gas always passes through the absorbent.

It is also conceivable to omit the third filter tube 12 and provide an absorbent filling the space between the folds in the filter tube 2. Also, only two true cylindrical tubes,
That is, it is also conceivable to configure the filter device with a filter tube that is not bent. Due to the presence of the absorbent, the permeating gas is freed of volatile or gaseous toxic components.

The filter device described above is particularly well suited for use in dust separators used for processing fumes produced during welding.

The invention is not limited to the embodiments described and illustrated above. For example, in addition to two filter layers,
More filter layers can be used, the innermost layer or first layer of which the airflow impinges cooperates with the bundle of strips described above.
For example, a very thin filter layer with a wide mesh fiber structure can be placed inside a folded coarse filter layer, which is preferred but not necessary. Similarly, filter layer 1 and filter layer 2
One or more additional fiber layers can be provided between the filter layer 1 and the fiber network structure having a mesh that is finer than that of filter layer 2 but wider than that of filter layer 1. filter layer 1
A fibrous mass can also be provided in the space between the filter layer 2 and the filter layer 2 for trapping fine foreign objects from the air flow after the air flow has passed through the coarse filter layer 2 and before reaching the fine filter layer 1. . This mass is, for example, cotton.

Furthermore, the concept of the invention is not limited to the purification of air; the filter device described above can of course also be used for purifying other gases.

If desired, special supports or frames may be integrated into the filter device, e.g.
A grid of metal, plastic or cardboard extending between the two plates 3 and 4 is incorporated, so that neither of the filter layers 1, 2 needs to be made rigid. Furthermore, the concept of the invention is not strictly limited to the geometrical shapes shown. The two filter layers, the coarse filter layer and the fine filter layer, do not have to be cylindrical, but can be of any other suitable shape. For example, two filter layers can consist of two continuous flat walls placed across a suitably shaped air dust. It is also possible to arrange two or more successive sets of coarse and fine filter layers. Furthermore, the strip material described above can be replaced with various movable elements, such as fibrous threads. The strip material or yarn elements can also be treated in various ways, for example by surface treatments to make them fire-resistant, in order to prevent the risk of fire caused by sparks, for example in welding, carried by the air current. . It is also conceivable that the strips or strip-like elements described above may be used in conjunction with simple tubes or bags forming coarse or fine filters.