JPH0350962Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a filter cloth for a center field type filter press, which has a stock solution supply hole approximately in the center and extends the filter cloth on both sides of the filter plate.

(Prior art) In a filter press in which a large number of filter plates each having stock solution supply holes penetrating the filtration surface are arranged closely together either directly or through a filter frame, two filter cloths spread on both sides of the filter plates are used as described above. Various methods have been adopted for bonding at the stock solution supply hole of the filter plate.

For example, as shown in FIG. 3, the filter plate has a stock solution supply hole 6 approximately in the center, and two filter cloths 1 stretched on both sides of the filter plate are placed around the periphery of the stock solution supply hole 6. The filter press is connected by a connecting cloth 2 sewn across the filter plate 5, and the connecting cloth 2 covers the stock solution supply hole which is provided through the filtration surface of the filter plate 5 and forms a protruding edge. Use a reinforced cloth with a larger outer diameter than the connecting cloth as disclosed in Japanese Utility Model Publication No. 53-51499, and sew its periphery to each of the two filter cloths. There is a filter cloth for a filter press in which the connecting cloth is sandwiched between a reinforcing cloth and a reinforcing cloth, and the three are sewn together. Furthermore, in order to prevent leakage of particles of the stock solution from the filter cloth, a method is adopted in which a connecting cloth is sewn to the main filter cloth and then an adhesive resin such as silicone or polyurethane resin is applied around the connecting cloth.

(Problems to be solved by the invention) Filter cloths for filter presses manufactured using the above-mentioned conventional technology have achieved good results in general filtration. When high compression is performed using a diaphragm or the like, leakage of raw solution particles inevitably occurs. Even if the filter cloth 1 and the connecting cloth 2 are appropriately selected to prevent the leakage of particles of the stock solution, particles will enter from the overlapped end A of the filter cloth 1 and the connecting cloth 2 on the filtration surface side when they are joined by sewing, and the filter cloth Particle leakage occurs due to particles passing through the overlapping portion of 1 and connecting fabric 2, and particles entering and passing through the needle hole of the sewing machine.

Furthermore, the method of applying the adhesive resin has the following drawbacks: (1) The application process is complicated, and it is difficult to uniformly apply the adhesive resin to the three-dimensional connected parts, which tends to cause uneven application. (2) In general, adhesive resins only form a film on the surface and are difficult to penetrate into the interior, and cannot completely seal the overlapping portion of the filter cloth and connecting cloth, making them unsuitable for long-term use.

The present invention considers the occurrence of particle leakage of raw solution and provides a filter cloth for filter presses that prevents particle leakage from the overlapped portion of sewing machine seams.

(Means for solving the problem) The present invention has a stock solution supply hole approximately in the center, and two filter cloths stretched on both sides of the filter plate are placed around the periphery of the stock solution supply hole. For a filter press, the connecting cloth is connected to the filter cloth by a connecting cloth sewn over the filter cloth, and the connecting cloth covers the stock solution supply hole which is provided through the filtering surface of the filter plate and forms a protruding edge. This filter cloth for a filter press is characterized in that a layer of water-swellable material is interposed and sewn to the joining surfaces of the two filter cloths and the connecting cloth.

The layer made of water-swellable material is preferably flexible, and is preferably made of acrylic, vinyl, monopolymer,
or a material containing a superabsorbent polymer such as a copolymer, a polyurethane polymer, cellulose, starch, or a modified or crosslinked product thereof; particularly preferred is a water-swellable polyurethane-containing flexible material; Particularly preferred is a flexible material made of a mixture of water-swellable polyurethane and natural rubber or recycled rubber.

As a method for interposing a water-swellable substance, (1) a sheet ring-like material made of the above substance is inserted between the filter cloth and the connecting cloth and sewn together.

(2) At least one side of the sheet ring made of the above substance is coated with an adhesive substance, the filter cloth, the sheet ring and the connecting cloth are temporarily joined, and then sewn together.

(3) After applying a liquid substance made of the above substance to the joint surfaces of the filter cloth or connecting cloth, the cloth is laminated and sewn together.

(4) A liquid substance made of the above substance is applied to the joining surface of the filter cloth or connecting cloth, and after semi-hardening, the two are sewn together.

You can choose either method.

(Function) When a layer made of a substance containing a superabsorbent polymer comes into contact with water or moisture, it absorbs water, retains water, and expands in volume by itself. Due to this expansion, the gap between the filter cloth and the connecting cloth and the needle hole passing through the water-swellable material layer are completely sealed, and particle leakage of the stock solution can be prevented.

Normally, in filter press filtration, the raw solution itself often contains water, creating an environment in which water-swellable substances swell.However, when using this filter cloth, water-swellable substances are pre-filtered immediately after attaching the filter cloth or immediately before filtration. The layer may be in contact with water.

(Embodiment) FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows another embodiment of the present invention.

In the embodiment shown in FIG. 1, a sheet ring-like material made of a water-swellable substance 3 is inserted and sewn into the joint between the filter cloth 1 and the connecting cloth 2. Further, in the specifications shown in FIG. 1, if the joint surface between the filter cloth 1 and the connecting cloth 2 is widened, wrinkles will occur. Therefore, in order to further improve the effect of preventing particle leakage, a reinforcing cloth 4 may be provided as shown in FIG. 2, and the layer made of the water-swellable substance 3 may be extended to the joint surface of the reinforcing cloth 4 and the filter cloth 1.

(Effect of the invention) As described above, in the filter cloth for the center field type filter press according to the present invention, the water-swellable substance interposed between the filter cloth and the connecting cloth acts, and the overlapped end of the filter cloth and the connecting cloth on the filtration surface side prevent particles from entering the
In addition, particles that enter through the needle hole due to sutures close the needle hole opened in the layer made of water-swellable material by self-volume expansion, preventing them from passing through to the non-filtering surface, completely preventing leakage of the undiluted solution particles. It is something.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional partial view of a filter plate and filter cloth for a filter press according to an embodiment of the present invention, Fig. 2 is a vertical cross-section partial view of the same as the above of another embodiment of the present invention, and Fig. 3 is a conventional cross-sectional view. FIG. 4 is a vertical cross-sectional view of the filter cloth of the filter press, and FIG. 4 is a partially cutaway front view of FIG.

Claims (1)

[Scope of utility model registration request] The filter plate has a stock solution supply hole approximately in the center, and two filter cloths are stretched on both sides of the filter plate, and a connecting cloth is sewn around the periphery of the stock solution supply hole so as to span the two filter cloths. In the filter cloth for a filter press, the two filter cloths and the A filter cloth for a filter press, characterized in that a layer of water-swellable material is interposed on the joint surface of the connecting cloth and sewn to the joint surface.