JPH0618567Y2 - Cartridge filter - Google Patents

Description

[Detailed Description of the Invention] (Prior Art) As a cylindrical cartridge filter, for example, a wound type of spun yarn or woolen yarn wound around a perforated tube (Japanese Utility Model Publication No. 61-12922), with a pleated A pleated type in which a filter cloth is mounted between a porous inner cylinder and an outer cylinder (Japanese Utility Model Publication No. 58-86211), or one formed by molding heat-adhesive composite fibers into a cylindrical shape (special (Publication No. 53-43709)
Etc. can be mentioned as a typical example. In most of these filters, the liquid flows from the outer peripheral side toward the inner peripheral side, during which fine particles in the liquid are removed.

(Problems to be solved by the invention) Although the above-described thread-wound cartridge filter has an advantage that the product cost is low, a part of the fiber forming the thread is dropped during the passage of the liquid, and the dropped fiber May be mixed in the filtered liquid, and the filtered liquid mainly passes between thread lattices having a relatively small fiber density, and is not suitable for highly accurate filtration. Further, the pleated type cartridge filter has a feature that the filtration surface is extremely large, but on the other hand, pleating processing of the filtering material, tubular processing, attachment of upper and lower end plates, attachment of porous inner and outer cylinders, etc. Inevitably, the material cost and the manufacturing cost increase, and the versatility is poor.

On the other hand, a cartridge filter formed by molding heat-adhesive fibers into a cylindrical shape does not require a porous core material, and since the fibers are adhered to each other, the fibers do not fall off and have a uniform high filtration accuracy. The advantage is that However, since the heat-adhesive fibers are formed by interfiber bonding, the range is small even if the inner and outer layers can have a density difference, and it is difficult to adjust the fiber density of the outer layer to, for example, 80% or less. is there. In addition, it is necessary to bond the end plates to the upper and lower end faces, and it is the fact that the end plates prevent the liquid from leaking from the end faces of the cartridge filter.

The present invention is a cartridge filter having a cylindrical shape formed by using a heat-adhesive fiber, in which the inner and outer layers can be formed to have a desired density difference, and liquid does not leak from the upper and lower end surfaces to the inside. Is provided.

(Means for Solving the Problems) The present invention forms a cylindrical filtration layer of an inner layer that is hardened by fusing a heat-adhesive fiber web while heating.
A non-woven fabric made of heat-adhesive fibers is wound around the outer periphery of the tubular filtration layer to form a pre-filtration layer having a fiber density lower than that of the tubular filtration layer, and the cartridge filter is provided with a depth filtration function, and the upper and lower end surfaces are heat treated. And is made into resin, and liquid impermeable resin films are formed on the upper and lower end surfaces.

The heat-adhesive fiber web forming the inner tubular filtration layer and the heat-adhesive fiber forming the non-woven fabric of the cartridge filter of the present invention include two kinds of synthetic fibers having a melting point difference of at least 20 ° C. or more. A composite fiber formed by spinning the coalescence is applied. The composite fiber may be of a core-sheath type or a parallel type as long as the low melting point component is melted by heat treatment and the fibers can be thermally bonded. For example, the high-melting point component is polypropylene, the low-melting point component is preferably polyethylene or ethylene-vinyl acetate copolymer-based polymer, and other polymers having different melting points, such as polyethylene, polypropylene, polyester, polyamide, vinyl chloride A composite fiber composed of two kinds of components is mentioned.

The tubular filtration layer as the inner layer is a method in which the above-mentioned heat-adhesive fiber web is wound in a cylindrical shape while being heated at a temperature not lower than the melting point of the low-melting component and not higher than the melting point of the high-melting component, or the heat-adhesive fiber. Can be obtained by a method of filling in a cylindrical space composed of a cylindrical inner frame and an outer frame and performing heat molding at the above temperature. Further, the outer pre-filtration layer is a sheet-shaped non-woven fabric obtained by heating and cooling the same heat-adhesive fiber web as the tubular filtration layer on the outer periphery of the tubular filtration layer obtained by the above method. It can be formed by winding until the layer thickness becomes, and so that the fiber density of the layer does not become larger than that of the tubular filter medium, and thermally bonding the final end.

The fiber density of this pre-filtration layer is the same as that of the above-mentioned tubular filter layer of interior.
About 1/3 to 2/3 is desirable, and if it is less than 1/3, not only the morphological stability deteriorates but also the porosity is too large and the pre-filtration effect becomes poor, and the substantial filtration effect is the cylindrical shape of the inner layer. The filtration life is shortened because it is performed in the filtration layer. On the other hand, if it exceeds 2/3, the fiber densities of the inner and outer layers become too close to each other, and the substantial filtering action is carried out on the surface layer of the pre-filtration layer, which lowers the function as the pre-filtration layer and reduces the depth filtration action. Cannot be achieved.

The above-mentioned resin film on the end face can be formed by heating the end face of the cartridge filter at a temperature equal to or higher than the melting point of the high melting point component of the heat-adhesive fiber to melt the fiber on the end face, and to resinize the surface fiber. it can.

(Operation) When the liquid to be filtered is passed from the outer peripheral side of the cartridge filter toward the center, the pre-filtration layer collects solids having a relatively large particle size in the liquid to be filtered, and solids having a small particle are removed. It exerts a deep-layer filtration function of collecting with a tubular filter material. The resin films on both end faces serve to seal the end faces, prevent liquid from leaking from the end faces to the central portion, and the tubular filtration layer also functions as a liquid-permeable core tube.

(Example) Example 1. A core-sheath type thermo-adhesive fiber (thickness 2 denier, fiber length 51 mm) made of polypropylene (melting point 167 ° C.) as core component and polyethylene (melting point 133 ° C.) as sheath component (weight: 15 g / m ² ). While melting the polyethylene component by heat treatment with hot air at 140 ° C, length 35 cm, weight 1.
A tubular filtration layer (1) was formed by winding on an iron core of 5 kg and a diameter of 30 cm while pressurizing so that the average fiber density was 0.3 g / cm until the winding diameter reached 55 mm. Then this tubular filtration layer (1)
A sheet-shaped non-woven fabric obtained by heat-treating a card web (weight per unit area: 30 g / cm ³ ) made of the above-mentioned heat-adhesive fiber with 150 ° C. around the outer periphery of After heat-adhering the end ends to form a pre-filtration layer (2) having a fiber density of 0.11 g / cm ³ , the iron core is removed and both ends are cut to form a 25 cm long two-layer structure cylindrical filter. did. Then, heat treatment is performed by applying an iron plate heated to 170 ° C to the cut end face, melting the heat-adhesive fiber on the end face side into a resin, and a cartridge filter having a film-like resin film (4) (4) on both end faces. (3)

Example 2. The fiber density was 0.3 g / by the same method as in Example 1.
fiber density on the outer circumference of the cylindrical filtration layer cm ³ (1) forms a cartridge filter with pre-filtration layer of 0.18 g / cm ³ (2),
Similarly, the end face was heat-treated.

Comparative example. The card web of the heat-adhesive conjugate fiber of Example 1 was wound by the method for forming a tubular filter material according to Example 1 while adjusting the pressure, and the fiber density of the inner layer was 0.33 g / cm ³ , and the fiber density of the outer layer was A cartridge filter having 0.27 g / cm ³ and a winding diameter of 65 mm was prepared.

The following table shows the results of a comparative test of the filtration lives of the cartridge filters of Example 1.2 and Comparative Example.

The test method was as follows.

10 minutes per minute from the outside of each cartridge filter toward the hollow part while uniformly stirring the suspension water of the test dust (Kanto loam, average particle size 8 μm) adjusted to a concentration of 200 PPM.
The forced flow of water is performed at the ratio of, and the total water flow rate when the water flow pressure for maintaining the water flow rate of 10 is +0.5, kg / cm ² , and +1.0 kg / cm ² is used as a guide for the filtration life. Filter life 1. Filtration life 2. Expressed as

(Effect of the Invention) As described above, the cartridge filter according to the present invention is a hard tubular shape formed by heating a thermoadhesive composite fiber web composed of two components having different melting points at the melting point temperature of the low melting point component to form a cylindrical shape. A non-woven fabric composed of heat-adhesive composite fibers is wound around the outer periphery of the filtration layer to form a pre-filtration layer having a fiber density lower than that of the tubular filtration layer, and the upper and lower end surfaces are heat-treated to be liquid impermeable. Since a resin film is formed, if the liquid to be filtered is applied to a filter that passes through the liquid from the outer surface toward the center, solids with a relatively large particle size in the liquid to be filtered are prefiltered. The fine solid matter that has passed through the layer (2) will be collected in the inner tubular filtration layer (1), and a so-called deep filtration effect will be achieved. Therefore, the filtration life is extended and the filter replacement cycle can be extended. Moreover, since the tubular filtration layer (1) is formed by fusing the heat-adhesive fibers, it has a stable resin-molded form, and not only the porous core tube is unnecessary but also the entire hollow inner peripheral portion. Even if some of the fibers of the outer pre-filtration layer (2) fall off while the filtration liquid is passing therethrough and the filtration function is improved, the filtration liquid is promoted by the tubular filtration material and is not mixed into the filtration liquid. Further, since the resin film is formed on the end surface of the cartridge filter, the invasion of the liquid from the end surface is surely prevented, and there is no fear that harmful substances are mixed into the filtered liquid.

[Brief description of drawings]

The drawing is a partial sectional front view illustrating a cartridge filter of the present invention. 1: Cylindrical filtration layer 2: Pre-filtration layer 3: Cartridge filter 4: Resin membrane

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Claims (1)

[Scope of utility model registration request] 1. A thermoadhesive composite fiber web comprising two components having different melting points is heated at the melting point temperature of its low-melting component to form an outer periphery of a hard cylindrical filtration layer formed into a cylindrical shape. A non-woven fabric made of fibers is wound to form a pre-filtration layer having a fiber density coarser than that of the tubular filtration layer, and upper and lower end surfaces are heat-treated to form a liquid-impermeable resin film. Cartridge filter to do.