JPH0576732A - Tubular filter - Google Patents

Abstract

PURPOSE:To provide a tubular filter which is possible to stably regenerate in high recoverability for a log time by back washing by welding a tip part of a polytetrafluoroethylene resin porous sheet each other piled up one over another on a wrapping part and a gap between an under part of the tip part of the polytetrafluoroethylene resin porous sheet and a porous hot melt sticking cylindrical supporting body with melting of a hot melt sticking material. CONSTITUTION:The laminated sheet of the polytetrafluoroethylene porous sheet 2 and the hot melt sticking material layer 3 less in flow resistance than the sheet 2 is provided in spiral wrap winding while bringing the hot melt sticking material 3 into contact with the supporting body 1 on the porous hot melt sticking cylindrical supporting body 1. And the tip part 21, 22 of the polytetrafluoroethylene porous sheet each other piled up one over another on the wrapping part 20, the gap between the tip part 22 and supporting body 1 and furthermore the sheet part adjacent to the tip part 21 of the wrapping part 20 and the supporting body 1 are welded with the hot melt sticking material 3. As a result, the cylindrical filter using the polytetrafluoroethylene resin porous film which is possible to stably regenerate in high recoverability for a long time by back washing method is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular filter using a porous tetrafluoroethylene resin membrane which can be stably operated for a long period of time by a regeneration system using a backwashing method.

[0002]

2. Description of the Related Art Porous tetrafluoride resin membranes are used for filtration of various liquids and gases because they have excellent filtration performance, chemical resistance and mechanical strength. Various types of membrane filters using this tetrafluoroethylene resin porous membrane have been proposed. As one type, a tubular type, a tetrafluoroethylene resin porous sheet is formed in a sheath shape. Then, the seam is joined with a heat-fusible material to produce a tubular membrane, and the porous tubular support is inserted into this tubular membrane, with the tubular membrane outside as the stock solution side and the tubular membrane inside as the permeate. Known as the side.

In any type of filter using a filtration membrane, deterioration of filtration performance over time due to so-called clogging is unavoidable.

A regeneration method is known as one method for coping with such a situation, and a method using a backwash method as one of the regeneration methods is known.

In this backwashing method, when the pressure on the raw liquid side increases to a predetermined pressure due to clogging of the filter, the filtration operation is interrupted and the filtrate in the filtrate tank is moved to the permeate chamber side of the filter by pressurized air or the like. It is a press-fitting method, is easy to automate, and is widely used.

[0006]

However, in the filter using the tetrafluoroethylene resin porous tubular membrane, the tetrafluoroethylene resin resin is inferior in adhesiveness,
Since sufficient strength cannot be imparted to the fused portion of the tetrafluoroethylene resin porous sheet, washing with a backwash method results in
The backwashing pressure causes the tetrafluoroethylene resin porous sheet
The fused portion of the sheet easily breaks, and the pore size of the tetrafluoroethylene resin porous sheet is enlarged by the backwashing pressure to promote clogging, and the recovery rate of the permeation performance by the backwashing is low.

An object of the present invention is to provide a tubular filter using a porous membrane of tetrafluoroethylene resin, which enables stable regeneration for a long time by a backwashing method with a high recovery rate.

[0008]

The tubular filter of the present invention
Is a lamination sheet of a tetrafluoroethylene resin porous sheet and a heat-fusible material layer having a flow resistance smaller than that of the sheet, and the laminated sheet has a spiral shape on the porous heat-fusible cylindrical support. Ends of tetrafluoride ethylene resin porous sheet, which are additionally wrapped by wrapping and under the contact of the heat-fusible material and the porous heat-fusible cylindrical support, and which are stacked one above the other in the wrap portion. Between each other and the upper and lower lower side tetrafluoroethylene resin porous sheet ends and the porous heat-fusible cylindrical support, or further, the upper side tetrafluoroethylene resin porous sheet of the wrap portion. And a porous heat-fusible cylindrical support member which is adjacent to the end portion of the aluminum tetrafluoride resin and is fused by the above-mentioned heat-fusible material. And a heat-adhesive conjugate fiber web having two components having different melting points is provided on a porous heat-fusible cylindrical support, and the melting point temperature of the low-melting component is A cylindrical body formed by molding, or a powder-sintered porous body obtained by heat-molding a thermoplastic resin powder at a temperature equal to or higher than the melting point thereof can be used. A heat-bondable composite fibrous web having components can be used.

[0009]

[Function] For fixing between the lower end of the wrap portion of the tetrafluoroethylene resin porous sheet and the porous heat-fusible cylindrical support, the wrap portion is made of the tetrafluoroethylene resin porous material. It can be stabilized against the tensile force based on the backwash pressure acting on the sheet,
The wrap can be prevented from being damaged as much.

Further, the expansion of the tubular tetrafluoroethylene resin porous membrane due to the backwashing pressure can be reduced, the promotion of clogging due to the expansion of the pore size of the membrane can be sufficiently suppressed, and the recovery of the filtration performance by the backwashing is effective. Get to.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a perspective explanatory view showing an embodiment of the present invention,
FIG. 1B is a sectional view taken along the line A-B of FIG.

In FIGS. 1A and 1B, reference numeral 1 is a porous heat-sealing tubular support. A is a laminated sheet obtained by adhering the porous sheet of tetrafluoroethylene resin 2 and the heat-fusible material layer 3 and wrapped around the porous heat-fusible cylindrical support 1 by wrapping. There is. Reference numerals 21 and 22 designate the ends of the porous sheet of tetrafluoroethylene resin which are vertically overlapped with each other in the wrap portion 20. The sheets of the sheet end portions 21 and 22 are adjacent to each other and the lower portion of the tetrafluoroethylene resin is porous. The end portion 22 of the high quality sheet and the cylindrical support 1 for heat-sealing heat are fused by melting of the heat-sealing material 3.

The fusion of the porous heat-fusible cylindrical support 1 and the heat-fusible material 3 is firmly carried out by the thermoplasticity of both, and the tetrafluoroethylene resin porous sheet end portion is formed. 21,2
The adhesion between the heat-sealable material 3 and the heat-sealable material 3 is performed by the anchor effect by the heat-sealable material 3 biting into the holes of the porous tetrafluoroethylene resin sheet 2.

FIG. 2 shows a module using the tubular filter of the present invention. 41 is a stock solution chamber housing, 42 is a stock solution pressure inlet, 43 is a backwash drainage outlet, 44 is a permeate chamber housing, and 45 is a permeate chamber housing. The permeate outlet, 46 is a partition. B is a tubular filter, the lower end of which is sealed with a curable seal material 47 and the upper end of which penetrates the partition wall 46, and between the partition wall 46 and the tetrafluoroethylene resin porous sheet 2. The upper end opening of the porous heat-sealing tubular support 1 is sealed and the permeate chamber housing 44 is sealed.
It has been introduced in.

To filter the undiluted solution by this module, the undiluted solution is press-fitted into the undiluted solution chamber housing 41 through the undiluted solution pressure inlet 42, and the whole amount is filtered.
When the filtration performance of No. 1 is lowered, the filtrate in the filtrate tank is pressed into the filter-B through the permeate housing 44 and backwashed to recover the filtration performance.

At the time of this backwashing, the porous sheet of tetrafluoroethylene resin is pressurized from the inside by the backwashing liquid (filtrate).
As shown in (b) of item (b), the tensile force F acts on the tetrafluoroethylene resin porous sheet 2. Therefore, the lap portion 20
In the above, there is a deviation of Δa between the pulling centers of the upper and lower overlapping tetrafluoroethylene resin porous sheet end portions 21 and 22, and when this wrap portion 20 is not fixed,
Upper and lower porous tetrafluoroethylene resin sheet ends 21,2
The rotational moment of FΔa acts on the joint portion of No. 2, but in the filter of the present invention, the lower side tetrafluoride ethylene resin porous sheet end portion 22 and the porous heat-sealing property. Since the wrap portion 20 is fixed for fusion bonding with the cylindrical support 1, the above-mentioned moment can be supported at this fixing portion, and the upper and lower ends of the porous tetrafluoroethylene resin porous sheet can be supported. The action of the moment on the joint portion of the portions 21 and 22 can be sufficiently eliminated. Therefore, the breakage of the end portion where the porous portion of the tetrafluoroethylene resin porous sheet is joined due to the backwash pressure can be alleviated.

In addition, since the tetrafluoroethylene resin porous membrane 2 is fixed to the porous heat-fusible cylindrical support 1 in the wrap portion 20, the tetrafluoroethylene resin porous membrane due to the backwash pressure is used. Since expansion can be well prevented and expansion of the pore size of the membrane can be suppressed, clogging of fine particles inside the membrane can be eliminated, and promotion of clogging can be avoided.

In the above, as shown in FIG. 3, the upper end portion of the tetrafluoroethylene resin porous sheet 21 of the wrap portion 21 is
A portion of the ethylene tetrafluoride resin porous sheet adjacent to
Is fused to the porous heat-fusible cylindrical support 1 by the heat-fusible material 3, the tensile force acting on the tetrafluoroethylene resin porous sheet 2 is applied to the fusion site b and the lap portion. The lower tetrafluoroethylene resin porous sheet end 22 of 20 and the porous heat-fusible cylindrical support 1 can be supported at the fusion-bonding portion a, and the tetrafluoroethylene resin porous sheet end can be supported. Since it is possible to prevent the pulling force from acting on the joint portion of the parts 21 and 22,
It is possible to further reduce the breakage at the end portion where the porous portion of the tetrafluoroethylene resin porous sheet is joined due to the backwash pressure.

In the above, as the porous heat-fusible cylindrical support 1, a support which can support the tetrafluoroethylene resin porous membrane 2 from the stock solution pressure and can be heat-welded is used. For example,
A porous body obtained by filling thermoplastic resin powder such as polyethylene, polypropylene, tetrafluoroethylene resin, etc. in a mold and heating it to a temperature above the melting point of the thermoplastic resin powder to bind the powder to each other. A non-woven fabric, a woven fabric, a porous sheet formed by winding a sheet-like sheet and heat-molded, and a sheet of a heat-adhesive composite fiber web having two components having different melting points are continuously formed by using a spiral winder. It is possible to use, for example, a porous body obtained by spirally winding a low-melting point component while heating and melting the low-melting-point component, and in the case of, the outermost periphery of the spiral spiral winding is a tetrafluoroethylene resin porous sheet and the sheet. The tubular filter of the present invention can be manufactured by wrapping a laminated sheet with a heat-fusible material layer having a flow resistance smaller than that of the laminated sheet, and welding the lap portion.

The above heat-fusible material 3 has a lower liquid passage or ventilation resistance than the tetrafluoroethylene resin porous sheet 2,
An adhesive having good mechanical adhesion to the tetrafluoroethylene resin porous sheet 2 and having a mechanical strength capable of reinforcing the tetrafluoroethylene resin porous sheet 2 against tensile force is used. For example, a heat-bondable composite fiber web having two components having different melting points can be used.

The melting point difference between the heat-fusible material 3 and the porous heat-fusible cylindrical support 1 is preferably 50 ° C. or less, and the same resin or at least the same component is used. Preferably.

The above-mentioned porous sheet of tetrafluoroethylene resin 2 has a pore diameter of 0.01 μm to 10 μm and a porosity of 40 to 40 μm.
95% can be used.

The tubular filter of the present invention can be used not only for filtration of liquid but also for filtration of gas. The heat fusible material 3 laminated on the tetrafluoroethylene resin porous sheet 2 and the heat fusible porous material. The material of the cylindrical support 1 is selected according to the liquid to be filtered, the type of gas, the temperature, and the like.

In the tubular filter of the present invention, a porous tetrafluoroethylene resin material is used for the membrane, but the lap portion can be sealed with excellent strength and the pore size of the membrane is increased by backwashing pressure. Since the promotion of clogging can be eliminated well, the backwashing method enables stable regeneration over a long period of time.
This can also be confirmed from the results of the reproduction test of the examples described below.

Example 1 In a tetrafluoroethylene resin porous sheet having an average pore diameter of 3.0 μm, a porosity of 90% and a thickness of 30 μm, two-component fibers having a polypropylene core and a polyethylene sheath were used. A non-woven fabric having a basis weight of 20 g / m ² is welded by melting polyethylene to obtain a laminated sheet, and the laminated sheet is cut into a width of 27 cm. The cut sheet has an outer diameter of 10 mm, an inner diameter of 6 mm and a long length. 50c
Wrapped on a polyethylene powder sintered cylindrical body of m with a wrap of 2 mm, the tetrafluoroethylene resin porous sheet ends 21 and 22 in FIG. A portion corresponding to between the resin porous sheet end portion 22 and the porous heat-fusible cylindrical support 1 was fused with a width of 1 mm.

Example 2 In contrast to Example 1, the tetrafluoroethylene resin porous sheet was placed between the end portions and the lower tetrafluoroethylene resin porous sheet.
3 is adjacent to the upper side tetrafluoroethylene resin porous sheet end portion 21 of the wrap portion 20 as shown in FIG. 3 except for the portion between the end portion and the porous heat-sealing tubular support. The porous portion including the tetrafluoroethylene resin porous sheet portion 23 was fused with a width of 2 mm.

Comparative Example The laminated sheet used in the examples was cut to a width of 16 mm and a length of 50 cm, and the cut sheets were fused together at the ends of both sides with the non-woven fabric surfaces being joined together. By doing so, a tube was obtained, and the polyethylene powder sintered cylindrical body used in the examples was inserted into this tube.

The lower ends of these Examples and Comparative Examples were sealed with a silicone sealant and incorporated in a housing to prepare a test module, and a backwash regeneration test was conducted with the test apparatus shown in FIG. It was

In FIG. 4, 51 is a stock solution tank, and 52 is
Is a pump, C is a test module, 53 is a backwash liquid (filtrate) tank, 54 is a pressurized air cylinder, and B _{2 to} B ₅
Is an electromagnetic valve, B ₁ is a regulating valve, and G ₁ and G ₂ are pressure gauges.

Water was put in a stock solution tank 51 of this test apparatus, and a stock solution prepared by dispersing JIS test dust II as filter particles with a stirrer was tested by a pump 52 as a test module C.
Was fed under pressure. In this case, the flow rate adjusting valve B ₁ was adjusted so that the stock solution chamber pressure of the module C (pressure of the gauge G ₁ ) was 0.10 kg / cm ² .

The whole amount of the undiluted solution flowing into the module C passes through the tubular filter B, and the backwashing liquid tank 53 and the electromagnetic valve B.
_It goes to the stock solution tank 51 through ₃ . At this time, the electromagnetic valves B ₄ and B ₅ are closed. Filter as the filtration progresses
As the clogging of B progresses, the pressure of the stock solution chamber of module C (gate
The pressure of G ₁ ) rises.

When the pressure of the gauge G ₁ reaches 1.0 kg / cm ² , the solenoids B ₂ , B ₃ are closed and at the same time the solenoid valves B ₄ , B ₅ are closed.
Is opened, and the filtrate in the backwashing liquid tank 53 is pressurized with air for 5 seconds at a backwashing pressure of 1.0 kg / cm ² or 2.0 kg / cm ² to form a porous heat-sealing tubular filter-B. It is pressed into the support (the backwash pressure G ₂ is set by the adjusting valve).

By this back washing, the adhered particles on the surface of the porous film of tetrafluoroethylene resin of the filter B are desorbed and reach the stock solution tank 51 through the electromagnetic valve B ₄ . After backwashing for 5 seconds, the electromagnetic valves B ₄ and B ₅ are closed at the same time as the electromagnetic valve B.
₂ , B ₃ are opened, the filtration operation is restarted, and when the stock solution chamber pressure of module C (pressure of gauge G ₁ ) reaches 1.0 kg / cm ² , backwashing is started again. After that, the above operation is automatically repeated.

The test results are shown in Table 1. In Table 1, the initial backwash after pressure immediately after the backwash in the initial stage module - le stock solution chamber pressure - a (gate pressure di G _1), the initial pressure after final backwash immediately after the backwash of the final The respective pressures of the stock solution chambers (the pressure of the gauge G ₁ ) of the module are shown.

[0035]

[Table 1]

It is apparent that the product of Example has a larger number of backwashing times than the product of Comparative Example, and that the lap portion of the membrane of the filter is stable against backwashing pressure.

Further, in the products of Examples, the initial pressure after the final backwash can be made substantially the same as the pressure after the initial backwash, and it is clear that the final backwash can restore the filtering characteristics to the same extent as the initial backwash. Is.

However, in the case of the comparative example product, the recovery rate is low in the final backwash. The reason for this is that the tetrafluoroethylene resin porous membrane expands due to the repeated action of backwash pressure, the pore size of the membrane expands, and clogging occurs inside the membrane as well. It can be estimated that the accumulation is remarkable. However, in the example product, the tetrafluoroethylene resin porous membrane is fixed to the porous heat-fusible cylindrical support at the wrap portion, and the tetrafluoroethylene resin porous film is formed by the repeated action of backwash pressure. The expansion of the membrane can be sufficiently suppressed and the backwash regeneration can be performed with a recovery rate superior to that in the examples.

[0039]

INDUSTRIAL APPLICABILITY The tubular filter of the present invention is constructed as described above, and the sealing property of the tetrafluoroethylene resin porous membrane against backwashing can be stably maintained, and the filtration performance is regenerated by backwashing. Can be performed with an excellent recovery rate. Therefore, according to the present invention, a tubular sheet having excellent maintainability, which is capable of stable filtration regeneration for a long period of time, using a porous sheet of tetrafluoroethylene resin having excellent filtration performance, customer resistance, and mechanical strength. A filter can be provided.

[Brief description of drawings]

1 (a) is a perspective explanatory view showing an embodiment of the present invention, and FIG. 1 (b) is a cross-sectional view taken along line (b) of FIG. 1 (a).

FIG. 2 is a cross-sectional view showing a module using the tubular filter of the present invention.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a circuit diagram showing a test apparatus used for a backwash regeneration test of the filter of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Porous heat-fusible cylindrical support A Laminated sheet 2 Tetrafluoroethylene resin porous sheet 3 Heat-fusible material layer 20 Lap part 21 Tetrafluoroethylene resin porous sheet end part 22 Porous ethylene tetrafluoride resin sheet end 23 Adjacent tetrafluoroethylene resin porous sheet portion

Claims (5)

[Claims] 1. A laminated sheet comprising a porous sheet of tetrafluoroethylene resin and a heat-fusible material layer having a flow resistance smaller than that of the sheet.
Is a spiral wrap around a porous heat-sealing tubular support,
In addition, the heat-fusible material and the porous heat-fusible cylindrical support are additionally provided, and the tetrafluoroethylene resin porous sheet end portions are stacked one above the other in the lap portion and the upper and lower portions thereof. A tubular filter characterized in that the end of the lower side tetrafluoroethylene resin porous sheet and the porous heat-fusible cylindrical support are fused by the above-mentioned heat-fusible material. -. 2. The porous heat-sealing tubular support according to claim 1, wherein the porous tetrafluoroethylene resin sheet portion is adjacent to the end of the upper portion of the tetrafluoroethylene resin porous sheet of the wrap portion. A tubular filter in which the body is fused with the heat-fusible material. 3. The heat-adhesive conjugate fiber web having two components having different melting points is formed on the porous heat-fusible cylindrical support at the melting point temperature of the low melting point component according to claim 1 or 2. A tubular filter using a tubular body. 4. A powder-sintered porous body obtained by heat-molding a thermoplastic resin powder at a temperature above its melting point on a porous heat-fusible cylindrical support according to claim 1 or 2. A tubular filter. 5. A tubular filter according to claim 1, 2, 3 or 4, wherein the heat-fusible material is a heat-bondable composite fiber web having two components having different melting points.