KR870000603B1 - Filtering devices - Google Patents

Abstract

A precision filter made entirely of bluororesin with high corrosion and heat resistance is described. A no. of tubular filtering elements are arranged in a fluororesin container. Each element has a PTFE tubular filtering film closed at I end and arranged over or inserted into a fluororesin tubular support. The filtering elements are connected to a cover structure, on the inner surface of which is formed a groove for communicating the elements to I of the liq. inlets and outlets provided in the cover structure.

Description

Filtration device

1A is a diagram showing an example of a tubular filtration membrane made of a sheet-like PTFE porous membrane.

1B is a view showing an example of a tubular filtration membrane made of a tubular PTFE porous membrane.

2A is a view showing an example of a PTFE three-dimensional sintered porous tube.

2B is a view showing an example of a fluororesin hole tube.

FIG. 2C is a view showing an example of a tubular support having a structure in which a fluororesin film is disposed outside the fluororesin hole tube. FIG.

3 is a sectional view showing an example of a filtration device.

4 shows an example of a support plate.

5A is a connecting part.

5b is a combination of a connecting part and a tubular support.

5C is a view showing an example in which a PTFE tubular filtration membrane is fused.

6 shows an example of a seal method.

7 is a cross-sectional view of a filtration device with a breathing valve.

8 is a longitudinal front view of a filtration device showing a detailed embodiment of the present invention.

9 is an enlarged cross-sectional view showing the main part of the statue.

Fig. 10 is a cross sectional view along arrow III-III in Fig. 9;

11 is an exploded perspective view of the same main portion.

12 is a cross-sectional view of a home seal used for frostbite.

* Explanation of symbols for main parts of the drawings

1: PTFE tubular filtration membrane opening end 2: Adhesion part

3: fluorine resin hole tube 4: fluorine resin network

5, 6: outer container 7: support plate

8: ornamental filter 9, 10: inlet or outlet

11: Seal 1 part 12: Fusion part

13: PTFE tubular filtration membrane 14: container

15: liquid inlet 16: liquid outlet

17: opening 18: breathing valve

19 filter medium 21 container

22: tubular filter 23: lid structure

24: outer case 25: entrance

26 outlet 27 support plate

28: fixed plate 30: ring

31: 0-ring 32: seal

33: home seal 38: communication home

38a: upper extremity

The present invention relates to a precision filtration device having excellent chemical resistance and heat resistance, in which all parts are made of fluorine resin.

Although many filtration apparatuses for separating fine particles contained in liquids or gases by fine filtration are well known, they are not known about precision filtration apparatuses having excellent chemical resistance and heat resistance. Even when a fluorine resin filtration membrane is conventionally used, a material inferior in chemical resistance and heat resistance is often used for the other part of the filtration device, which results in the whole being regulated by the properties of those materials. In addition, most of the seal materials are rubber packings, and there are many problems in terms of chemical resistance. In addition, the area of the filtration membrane per unit volume of the filtration device is small, and in many cases, a large amount of filtration flow cannot be taken.

The present invention is to provide an all-fluorine resin microfiltration device having excellent chemical resistance and heat resistance, which has been improved.

Hereinafter, the configuration of the present invention will be described in detail with examples.

In the present invention, it is preferable that the once closed polytetrafluoroethylene (hereinafter abbreviated as PTEF) tubular filtration membrane is formed by processing a sheet or tubular PTEF porous membrane into an obstructed tubular tube. The pore size is usually selected and used according to the use in a thing of 0.01-100 micrometers. In particular, the sheet or tubular PTEF porous membrane produced by the stretching and sintering method is optimally composed of one block of tubular shape. In order to manufacture a PTEF porous membrane by an extending | stretching sintering method, the method of Unexamined-Japanese-Patent No. 42-13560 is employ | adopted basically. The PTEF porous membrane produced by this method is characterized by having a microstructure composed of fibers and nodules interconnected by the fibers, and has a high mechanical strength, a fine and uniform pore size, and a large porosity, so that a per unit area can be produced. The filtration flow rate of the filtration can be increased, and the filtration membrane is optimal.

The PTFE porous sheet can be formed into an tubular shape by adhesive processing as in Fig. 1a. Adhesion of the PTFE porous membrane is achieved by heating above the melting point (about 327 ° C) of PTFE while polymerizing and pressing the porous membrane. It is also achieved by infiltrating the fluorine resin into the pores of the PTFE porous membrane by heating above the melting point of the fluorine resin inserted while inserting and pressing a film or powder of another fluorine resin during polymerization with the PTEF porous membrane.

Examples of the fluororesin used for this purpose include tetrafluoroethylene-hexafluoropropylene (FEP), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETF), polychlorotrifluoroethylene (PCTFE), polyvinyl fluoride (PVF), chlorotrifluoroethylene-ethylene copolymer (ECTFE), etc. are mentioned. In particular, when heat resistance chemical resistance is required, it is appropriate to use FEP or PFA.

In this invention, it is good to use two types of PTFE porous membranes from which a pore size differs. This purpose is to impart a role as a prefilter to the PTFE porous membrane having the larger pore diameter, to prevent clogging of the eye of the membrane, and to impart strength against back pressure. Combinations of PTFE porous membranes with pore sizes of 0.01-100 μm and 0.1-500 μm, respectively, are suitable.

Suitable as the fluororesin tubular support is a PTFE three-dimensional sintered porous pipe. This is a molded article having a communication hole produced by molding and heating and sintering a PTFE solid. It is effective to select one having a pore size larger than that of the filtration membrane which is usually used having a pore size of 0.1 mu m-1 mm to lower the filtration resistance. This sintered porous molded tube is particularly useful as a support because of its good permeability and poor deformation.

Another suitable example of the fluororesin tubular support is a laminate of a layer composed of a fluororesin network molded article or a nonwoven fabric and a layer composed of a fluororesin hole tube. Here, the network molded article or nonwoven fabric of the fluororesin is intended to take up the effective area of the filtration membrane, and to increase its pore size than the filtration membrane is required to lower the permeation resistance. The fluororesin network molded article may be integrally formed into a mesh, or may be a woven or knitted fabric. In addition, a fluororesin hole tube generally has a structure as shown in FIG. The shape of the hole is generally circular, but may be any other shape. On the outer surface or the inner surface of the fluororesin hole tube, a molded product or a nonwoven fabric of fluororesin is disposed. In the case of an external pressure type apparatus that is filtered from the outside of the tube to the inside, in the case of an internal pressure type apparatus in which a fluororesin reticulated article or a nonwoven fabric is disposed outside the fluororesin hole tube (FIG. 2C) and filtered out from the inside of the tube. Inside the fluororesin hole tube, a molded or nonwoven fabric of fluororesin is disposed. PTFE, FEP, PFA, ETFE, PCTFE, PVDF, PVF, ECTFE etc. are mentioned as an example of the fluororesin which is a material of these tubular supports. In particular, when heat resistance chemical resistance is required, PTFE, PEP, PFA, etc. are effective.

The once closed PTFE tubular filtration membrane covers or is inserted into the outside of the fluororesin tubular support. In the case of an external pressure type apparatus, the PTFE tubular filtration membrane is provided outside the fluororesin tubular support, whereas in the case of the pressure resistance type apparatus that is filtered from the inside of the tube to the outside, the PTFE tubular filtration membrane is provided inside the fluororesin tubular support. The PTFE tubular filtration membrane may be previously configured in the shape of occlusion, or may be blocked by fusion bonding the terminal of the PTFE tubular filtration membrane to the fluorine resin tubular support. The combination of the PTFE tubular filtration membrane and the fluororesin tubular support constitutes the tubular filter of the present invention. One or more of these tubular filters are arranged in a fluororesin container. Examples of the fluororesin include those such as the fluororesin of the tubular support. An example arrangement is shown in FIG.

In Fig. 3, the fluororesin container is basically composed of the outer containers 5 and 6 and the support plate 7, and the container of a is provided with the inlet and the outlet of the fluid on one side of the container, The container is provided with inlets and outlets on both sides of the container. (8) is a tubular filter, the open end of which is fixed to the support plate (7). In FIG. 3, when the filter is filtered from the outside to the inside of the pipe, the inlet of the fluid is (9), and the outlet is (10). On the contrary, when it is filtered from the inside of the pipe to the outside, the inlet of the fluid is (10), and the outlet is (9). As an example of the support plate 7, a hole disc like FIG. 4 is generally used. As an example of the method of fixing and sealing a tubular filter body to a support plate, the method by a taper screw, the method by heat welding, or a combination of both is suitable. Here, the thermal fusion includes a method of pressing with a jig heated above the melting point of the resin, a method using high frequency induction heating, or ultrasonic waves. Moreover, you may use the connection component of a fluororesin for both connection parts. An example is shown in FIG. In FIG. 5, a is an example of a connection part, b is an example which combined the connection part and the tubular support body. The tubular filtration membrane was capable of terminal sealing by heat-sealing the open end of the tubular support or the connecting part or by inserting it into the set screw part. The obstruction of the tubular filter is fixed with the bottom of the container (Figure 3a), or with a suitable support plate (Figure 3b). In addition, as the fixing seal of the outer container and the support plate, a method using heat fusion, a screw, a fluororesin 0-ring, or the like is used. Moreover, the method of extruding from both sides by the fitting structure as shown in FIG. 6 was especially effective. In order to compress from both sides, it was suitable to put this fluororesin container in the container with the flange of metal or resin body, and to compress. This method also has the advantage of increasing the internal pressure of the vessel. Also in this case, since only the fluororesin container comes into contact with the fluid, the chemical resistance does not deteriorate at all.

Examples of the filtration fluid of the filtration apparatus of the present invention include water, organic solvents, various solutions, various gases, and the like. Among them, a liquid having a relatively large surface tension represented by water, an aqueous solution, and some organic solvents is used as a filtration object. An opening with a breathing valve may be provided in the container. Here, the breathing valve is a non-liquid and breathable breathing valve composed of a fluororesin porous body. Therefore, the breathing valve does not permeate the liquid to be filtered under the pressure and temperature conditions of the filtration, and the gas is free to permeate. Fluorine resin porous body is most suitable for the respiration valve. The pore size of the fluororesin porous body will be selected based on the surface tension and the filtration pressure of the liquid, which are determined by the type and temperature of the liquid to be filtered.

The smaller the surface tension of the liquid and the higher the filtration pressure, the smaller the pore size of the fluororesin porous body used for the breathing valve. The most suitable material for this fluororesin porous material is also PTFE. Normally, the breathing valve is installed by sealing a sheet-like thing to the opening of the apparatus by a method such as adhesion or mechanical sealing. When the PTFE porous body is in the form of a sheet having a thickness of 0.1 mm, and the liquid is water having a temperature of 20 ° C., the impermeability to water pressure of about 1.1 kg / cm 3 is exhibited at a mean pore diameter of 10 μm, and the average pore size is 0.45 μm and 0.22 μm. And water permeability up to about 2.5 kg / cm 3 and about 4.5 kg / cm 3, respectively. The breathability was all good.

Breathing valves are installed in at least one of the openings of the filtration system. Usually, it is provided above the liquid inlet side of a filtration apparatus, but may be installed also in an outlet side. 7 is a diagram showing an example of a filtration device in which a breathing valve is provided above the liquid inlet side. The open end of the breathing valve may be used open or connected to another suitable pipe. As a result of the filtration using a filtration device as shown in FIG. 7, air bubbles entering the liquid from the liquid inlet are discharged from the breathing valve, and bubbles are not accumulated above the filter medium, and a decrease in the filtration flow rate does not occur. Did. In addition, it was found that bubbles are not mixed in the filtered liquid and are very effective as a filtration device for liquids. In addition, when the drain is removed, the breathing valve serves as an air inlet and the intake air is filtered through the breathing valve, so that the water does not enter the inside of the filtering device and the liquid. The next time the filtration starts, the breathing valve becomes the outlet of the air and proceeds smoothly. A filtration device with a breathing valve is very effective when the filter medium is liquid-repellent.

For example, if the filter medium is made of a fluorine resin with a small pore diameter and the liquid is water, the filter medium is usually wetted with a liquid having a small surface tension and then replaced with water to filter the water. Since it is dried and returns to its original water repellency, the effective area of the filter body is lowered, resulting in a decrease in the filtration flow rate. However, when the filtration device of the present invention is used, gas is discharged from the breathing valve, and this action does not occur. In addition, even when the drain is removed, the filter medium is often dried, and even after filtration, the original flow rate cannot be obtained. However, when the filter device of the present invention is drained and the liquid is re-injected, air is sucked in and out through the breathing valve. As a result of this, the filter medium is not dried, and therefore, a decrease in flow rate does not occur.

A more specific embodiment of the filtration device of the present invention will be described below.

As shown in FIG. 8, the basic structure of the filtration apparatus of the present invention includes a container 21 having an open end, a plurality of tubular filters 22 accommodated in the container 21, and a tubular filter 22. The lid structure 23 for supporting the container 21 to be closed is made of fluorine resin, and is mounted in a compressed state in an outer case 24 such as stainless steel.

The fluid flowing into the container 21 from the inlet 25 provided in the lid structure 23 is filtered out from the outside of the tubular filter 22 and taken out from the outlet 26.

However, the filtration device has a great influence on the sealing performance of the connection part or the closed part of the fluid passage. In the precision filtration device as described above, the connection part or the lid of the tubular filter 22 and the outlet 26 is A completely airtight or watertight connection structure or a seal structure should be adopted for the closed portion of the container 21 by the structure 23 or the like. However, fluorine resins such as ethylene tetrafluoride resins used as the material for forming the lid structure 23 or other parts tend to cause permanent deformation by compression, and thus the lid structure 23 has passage connection portions. It is necessary to employ a structure that makes the occurrence of deformation difficult in forming.

In this embodiment, the container for storing the tubular filter body is closed with a lid structure, and the lid structure is provided with a communication groove for conducting one side of the inlet or the outlet to the tubular filter body, and part of the communication groove is jointed. It is formed in the annular shape to minimize the reduction of the material of the lid structure to prevent the occurrence of deformation.

As shown in the figure, the lid structure 23 for closing the bent portion of the container 21 is a combination of a support plate 27 for mounting a plurality of tubular filters 22 and a fixed plate 28 overlapping the outer surface of the support plate 27. It consists of a support plate 27 and the fixed plate 28 are all formed using a fluorine resin and the same disk shape as the outer diameter of the container 21.

The support plate 27 is formed with a plurality of through holes 29 in the central portion and the periphery thereof, and the upper end of the tubular filter 22 is connected to each through hole 29 as shown in FIG. 9.

The seal which makes each overlapping surface airtight and watertight at the position which was convenient to the outer periphery in the overlapping surface of the said support plate 27 and the container 21, and the overlapping surface of the support plate 27 and the fixed plate 28. The structure is installed.

This seal structure uses a seal 32 provided with a 0 ring 31 inside a ring 30 formed in a cross-sectional shape using a fluorine resin, and a home seal 33 at the inner position thereof, thereby providing a seal effect. It is formed to aim at the improvement.

As shown in FIG. 13, the groove seal 33 forms a V-shaped groove 34 at one side of the overlapping surface and a V-shaped protrusion 35 at a wider angle than the groove 34 at the other side. It is configured to seal at the pressure contact.

The lid structure 23 is provided with an inlet cylinder 36 and an outlet cylinder 37 connected to the fixing plate 28 to communicate with the inside of the container 21 by penetrating the fixing plate 28 and the support plate 27 up and down. And the communication groove 38 which connects the outlet cylinder 37 and the tubular filter 22 group in the overlapping surface with the support plate 27 of the fixed plate 28 is provided.

The communication groove 38 connects the arcuate portion 38a cut out at the portion through which the inlet tube 36 penetrates as shown in FIGS. 10 and 11 and the tubular filter located at the center with the arcuate portion 38a. The arc portion 38a communicates with the entire group of tubular filters 22 arranged in a circular shape when the fixed plate 28 is superposed on the support plate 27. Therefore, the fluid flowing into the container 21 from the inlet 25 passes through the tubular filter 22 from the outside to the inside, and is then collected in the communication groove 38 and taken out from the outlet 26.

The filtration device of the present invention uses a fluororesin support of a specific shape of the PTFE porous membrane, which is the best filtration membrane, and is excellent in removing particulates from the fluid, filtration flow rate, chemical resistance, and heat resistance because all components are composed of fluororesin. to be. Therefore, it can be used for microfiltration of almost all fluids and can efficiently handle corrosive or hot fluids, which have been difficult to filter in the past.

Claims (16)

A filtration apparatus, characterized in that a pleated polytetrafluoroethylene ethylene tubular filtration membrane is disposed in a fluororesin container having an inlet and an outlet of a fluid, in which a tubular filter having a structure enclosing the outer side of the fluororesin tubular support or inserted therein is disposed. . The filtration apparatus according to claim 1, wherein the polytetrafluoroboethylene ethylene tubular filtration membrane has a pore size of 0.01-100 µm. The filtration apparatus according to claim 1, wherein the polytetrafluoroethylene ethylene tubular filtration membrane has a microstructure composed of fibers and nodules interconnected by the fibers. The filtration apparatus according to claim 1, wherein the polytetrafluoroethylene tubular filtration membrane has a structure in which two kinds of polytetrafluoroethylene ethylene porous membranes having different pore sizes are superimposed. 5. The filtration apparatus according to claim 4, wherein the two kinds of polytetrafluoro ethylene porous membranes having different pore diameters have pore sizes of 0.01-100 mu m and 0.1-500 mu m, respectively. The filtration apparatus according to claim 1, wherein the fluorine resin tubular support is a polytetrafluoroethylene-sintered porous molded tube. The filtration apparatus according to claim 6, wherein the sintered porous formed tube has a pore size of 0.1 µm-1 mm. The fluororesin tubular support according to claim 1, wherein the fluororesin tubular support is a laminate of a layer made of a fluororesin reticulated or nonwoven fabric having a larger pore diameter than the filtration membrane, and a layer made of a fluororesin hole tube. A filtration device, characterized in that a layer composed of a nonwoven fabric is disposed on the filtration membrane side. The filtration apparatus according to claim 1, wherein the fluororesin tubular support is once closed. The filtration apparatus according to claim 1, wherein the open end of the polytetrafluoroethylene tubular filtration membrane is fused to the fluororesin tubular support. The non-liquid and breathable breathing valve according to claim 1, wherein the fluorine resin container has an opening at at least one place other than the inlet and the outlet of the fluid, and at least one of the openings is provided with a non-liquid and breathable breathing valve. Filtration device. 12. The filtration apparatus according to claim 11, wherein the fluororesin porous body is a polytetrafluoroethylene porous body having a micro structure composed of fibers and nodules interconnected by the fibers. The filtration apparatus according to claim 11, wherein the fluororesin porous body is a polytetrafluoroethylene nonwoven fabric. 12. The filtration apparatus according to claim 11, wherein a non-liquid and breathable breathing valve is provided on the liquid inlet side of the container. The filtration apparatus according to claim 1, wherein a plurality of tubular filters having free ends are closed in a lid structure having an inlet and an outlet of a liquid, and a filtration device in which a bent portion of a container for storing the tubular filters is sealed with a lid structure. And a communication groove for conducting one of the tubular filter group and one of the inlet or the outlet in a lid structure provided with a filter medium, and the communication groove is formed in a shape of a cut-out arc. 16. The container structure according to claim 15, wherein the lid structure comprises a support plate for sealing the vessel equipped with a tubular filter and a fixed plate overlapping the outer surface of the support plate with a seal structure therebetween, and a communication groove is formed on the support plate overlapping surface of the fixed plate. Filtration device.

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