JPH09187627A - Hollow-fiber membrane filter and method for removing its contaminant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove the minute matter clogging the thin tube of a hollow-fiber membrane and the suspended matter depositing on the membrane surface with an accumulated liq. pressure by backwashing from the permeation side of the membrane. SOLUTION: A vessel 1 is closed, pipe openings 5 and 6 are provided respectively on the side and bottom of the vessel on the liq. feed side, and a first valve means 7 and a second valve means 8 are furnished to the respective openings. Further, a third valve means 9 is provided to the liq. passage 10 of the energizable structure. A vessel part 4 is formed with an elastic high molecular resin member capable of being expanded and contracted. A liq. staying in the vessel part 4 is backwashed off under pressure by the contractible repulsive force. As a result, the material clogging the thin tube and the suspended matter depositing on the membrane surface are washed off in a short time without using chemicals or additional devices.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber filter, and more particularly to a backwashing mechanism and method suitable for removing contaminants from the hollow fiber filter.

[0002]

2. Description of the Related Art As a pretreatment device for drinking water or industrial water, a hollow fiber filtration device formed with a hollow fiber filtration material for removing minute contaminants contained in raw water has been used. The hollow fiber filter material is composed of a large number of fine pores opened in and out of a thin tube having a fibrous form, and since the filtration area can be widened, the fine pores are 0.1 to 0. Since it is as fine as 2μ, it is possible to prevent passage of minute substances and substances containing bacteria. For this reason, it is particularly suitably used as a filtering material for water purifiers for the purpose of filtering drinking water.

The treated water that has passed through the hollow fiber filter material can remove even suspended substances and bacteria of the water as described above due to its fine pores, but in the long-term use, the filtered fine material becomes fine pores. Enter and block. For this reason, the hollow fiber filter material is frequently replaced or washed, etc., and the solid content clogged in the fine pores, or during filtration, it reaches the fine pore entrance according to running water, and it is larger than the fine pore diameter It is necessary to secure the amount of filtered water by often removing the inorganic substances and organic substances including bacteria that have accumulated on the surface of the pores. Thereby, it is possible to discharge the treated water stably and continuously in a state where the minute substance is removed.

[0004] As a means for removing such substances that block the pores contaminated by the suspended substances and microscopic substances and block the entrances of the microscopic pores, flushing with water, washing with acid, etc., according to the properties of the substances, Various processing methods have been considered. For example, the adhesion of the suspended solids to the micropore inlets can be relatively easily removed by flushing with water, and washing with an acid is effective for carbonate-scale micropore contamination. However, removal may be difficult depending on the type of the deposit.

Therefore, a membrane having fine pores similar to that of a hollow fiber membrane filter is disclosed in Japanese Patent Laid-Open No. 54-16268.
No. 4, in a filtration membrane through which particles ranging in size from molecular size to ionic size pass, in order to remove contaminants in the pores of the membrane together with the membrane surface, first, the membrane itself is decomposed on the front or back surface of the contaminated membrane. After a chemical solution for generating a gas body, for example, carbonate, hypochlorous acid, peroxide, and sulfite is contact-permeated, the chemical solution is removed, and further, a decomposing agent that decomposes the chemical solution is contacted. , For example, carbon dioxide,
By generating gas such as chlorine gas, oxygen, and sulfurous acid gas, gas is generated in the pores in the film, and contaminants on the film surface are easily separated from the film surface, and the substances in the pores move. The above means is intended to recover the contaminated film.

Although the means for recovering the contaminated film is certainly one of the means for recovering the contamination, in order to remove the solid content, a gas-generating chemical must be used. Depending on the gas generated, not only is it dangerous, but there is a cost associated with the chemicals used. Furthermore, in order to remove the adhered chemicals until the chemicals flow out after the treatment,
The running water that passes through the pores must continue to flow as waste water. As described above, in order to recover the contaminated film by the above-mentioned means, not only a complicated operation is required, but also the economical efficiency is low, so that it is impossible to use it in a water purifier for household use.

Japanese Unexamined Patent Publication (Kokai) No. 7-289860 describes a method for cleaning a hollow fiber membrane module for filtering a filtrate containing fine particles and suspended substances. A hollow fiber membrane used for this type of filtration is a compact device, but in order to have a wide filtration area, hundreds to tens of thousands of flexible thin tubes formed into a filament are bundled into a U-shape. It is folded or straightened, and its end is fixed with an adhesive, that is, the hollow fiber membrane module is stored in a container or the like for use.

[0008] As described above, when the filtration of the hollow fiber membrane module is continuously performed, a fine substance is blocked in the fine tube or a suspended matter is attached to the membrane surface. Then, the passing pressure is increased. For this reason, in order to remove the adhered suspended matter, air scrambling is regularly performed to introduce pressurized air from the air introduction port provided at the bottom of the container in which the hollow fiber membrane module is housed.

This air scrambling can be carried out after a certain period of time has passed after passing the running water or when the pressure of the running water through the membrane reaches a predetermined pressure. In this case, pressurized air is required. Not only that, it requires a measurement function to measure the rise in pressure, which increases the price of the device, which makes it difficult to use. Furthermore, the time for air scrambling is relatively long, and the time for cleaning for water supply and drainage is also required. In the above-mentioned publication, after scrubbing air, the cleaning time is shortened by draining water while the pressure in the container is increased, but even with this means, it cannot be said that the cleaning time is sufficiently shortened. is there. Above all, there is a problem that many effects cannot be expected to remove the substance that blocks the microtubules.

[0010]

SUMMARY OF THE INVENTION Therefore, the present invention is intended to remove the minute substances that block the hollow fiber membrane microtubes and the suspended matter adhering to the membrane surface with the accumulated liquid pressure. Not only can chemicals and other equipment not be used, but the cleaning time can be shortened relatively. Moreover, since backwashing is performed by applying liquid pressure from the passage side of the membrane, not only removal of suspended matter adhering to the membrane surface but also removal of substances that block the microtubes without using a special flow tube operation, It can be performed stably and safely. Further, since the installation and maintenance are easy and the cost is high, the hollow fiber membrane filtration device and the contaminant removal method are suitable.

[0011]

A hollow fiber membrane filtering device according to claim 1 of the present invention is a container which houses a hollow fiber membrane module in a container body, and which is a container constituting a hollow fiber membrane passing side of a filtrate. At least a part of the body and the liquid passage tube is composed of a biasing structure that swells with the pressure of the filtrate and contracts with the decrease of the pressure, and the input side of the container body that supplies the liquid to the hollow fiber membrane. Has a first valve means for controlling the supply liquid and a second valve means for discharging the waste liquid in the container body, and the third valve means or an equivalent effect is provided on the liquid passage side of the biasing structure. It is characterized in that a pressure closing means having is provided.

The hollow fiber membrane filtering device according to a second aspect of the present invention is characterized in that an external urging means for urging the urging structure from the outside to the inside is additionally provided.

A hollow fiber membrane filtering device according to a third aspect of the present invention is the hollow fiber membrane filtering device according to the first aspect, wherein the urging structure comprises a pressure tank communicating with the liquid passage.
The pressure tank is characterized in that it comprises means for accumulating the pressure of the filtrate.

The hollow fiber membrane filtering apparatus according to a fourth aspect of the present invention is characterized in that the filtrate is an aqueous solution and the pressure is a supply water pressure.

A method for removing contaminants from a hollow fiber membrane filtration device according to a fifth aspect of the present invention is the method for removing contaminants in a hollow fiber membrane filtration device according to any one of the first, second, third and fourth aspects of the present invention. The first and third signals are detected by the detection signal of the means.
The valve means is closed, the second valve means is opened, and backwashing is performed with the accumulated pressure of the biasing structure.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an embodiment showing the structure of a hollow fiber membrane filtering apparatus in which the present invention is carried out.

In the figure, 1 is a container body, 2 is a hollow fiber membrane module in which one end of U-shaped bundled hollow fibers is fixed with a resin 3, and the U-shaped side is housed in the container body 1 with the U-shaped side as the liquid supply side. There is. The side of the container body 1 through which the filtrate passes through the hollow fiber membrane is fixed with the above resin, and the upper part of the figure is a container part 4 in which the filtrate remains. The container portion 4 is formed of a biasing member that swells with the pressure of the filtrate and contracts as the pressure decreases. The container body 1 has a hermetically sealed structure, and on the liquid supply side thereof, respective pipe mouth portions 5 and 6 are opened at side and bottom portions, and first pipe means 7 and second valve means are provided at each pipe mouth portion. 8
Is provided. Further, a third valve means 9 is provided in the liquid passage 10 of the biasing structure. The container portion 4 is formed of a polymer resin member that is inflatable and contractible and has elasticity.

Water discharge side 1 provided with third valve means 9
In some cases, a post-treatment device for further treating the filtrate treated with the hollow fiber membrane filtration device may be installed at 8. For example, this is a case where a reverse osmosis membrane device or the like is used to obtain water close to pure water. When such a device is installed, a pressure load is generated on the water discharge side 18. Therefore, the same operation as that of the third valve means can be performed without providing the third valve means 9 due to the fluctuation of the pressure load. it can. That is, since the pressure closing means equivalent to the third valve means is configured, in this case, the third valve means 9 can be removed.

In the present invention, the liquid to be filtered can be any hydrophilic or lipophilic liquid as long as it is a liquid that can be filtered with a hollow fiber membrane, but it can be particularly preferably used for filtering drinking water. In this case, since the pressure required for backwashing can be performed by tap water pressure, it is not necessary to install equipment for this purpose.

2A and 2B are views for explaining the operation of the hollow fiber membrane filtering apparatus according to the present invention. FIG. 2A shows a case where the hollow fiber membrane filtering apparatus is operated for filtering, and FIG. It is a figure at the time of backwashing a hollow fiber membrane, and FIG.2 (c) is a figure at the time of washing the hollow fiber membrane surface. The description of the same operation as that of the embodiment shown in FIG. 1 will be omitted.

In FIG. 2A, the first valve means 7
Is opened and the second valve means 8 is closed. Further, the third valve means 9 is opened slightly closer to the closed side than the first valve means 7. In this state, when tap water is supplied as a liquid from the first valve means 7 to the hollow fiber membrane module in the direction of the arrow, the tap water is filtered by the hollow fiber membrane by the pressurizing pressure of the tap water and at the same time fine It reaches the container part 4 through the hole. At this time, the third valve means 9
Is opened to a slightly closed side from the first valve means 7, so that a part of the filtered liquid flows to the water discharge side 18 and a pressurizing pressure of tap water is applied to the container part 4, so that the container part 4 is filtered. It swells with the pressure of the liquid until the internal volume of the container section equilibrates with the pressurizing pressure of tap water.

In this state, if the first valve means 7 and the third valve means 9 are closed and the second valve means 8 is opened, as shown in FIG. 2 (b), the bulged container Since the portion 4 is cut off from the tap water pressure, the portion 4 is reduced, and the accumulated water in the container portion 4 is caused to flow backward from the fine holes of the hollow fiber membrane and is drained from the second valve means 8 in the direction of the arrow. At this time, since the water flow is momentarily backwashed with the pressure applied to at least the bulging of the container portion 4, the blockages in the pores are returned from the pores to the supply side. In addition, substances clogged at the pore entrance can be removed.

Further, as shown in FIG. 2C, the third valve means 9 is closed, the first valve means 7 and the second valve means are opened, and the first valve means 7 to By passing water through the valve means 8 of No. 2, it is possible to wash the substance blocked at the pore inlet. In the above,
Although the first valve means 7 has been described as the tap water supply side and the second valve means 8 as the drainage side, the second valve means 8 is conversely described.
Can be the tap water supply side and the first valve means 7 can be the drain side.

The opening and closing of the valve means of the husband and the wife can be manually performed as a manual, but preferably, the opening and closing of each valve is an electrically driven type, and as shown in FIG. Can be provided and controlled. For example, when the first valve means 7 is closed after the end of use, the third valve means 9 is interlocked and closed at the same time as the second valve means 7.
The valve means 8 is opened interlockingly. As a result, the state shown in FIG. 2B is performed together with the control of the control unit, and the backwash is surely performed immediately after use. These are controlled by the CPU 12 that constitutes the control unit 11 and the ROM 13 that stores the opening information of the hull.

The control by the CPU 12 is as described above.
In addition to the control information stored in the ROM 13, the control can be performed based on a signal from a sensor arranged in the container portion. That is, when the pressure of the pressure sensor 17 arranged in the container 4 does not rise as compared with the supply liquid side pressure sensor 16 due to the increase of the contamination resistance of the hollow fiber membrane, it is considered that the hollow fiber membrane is clogged and the above-mentioned condition is taken into consideration. It can be backwashed in this way. Further, it is also possible to perform arithmetic processing on each signal separately, or perform arithmetic processing on the sum, difference, product, etc. of each signal to output a control signal and issue a control signal to perform control to secure an optimum flow rate.

[0026]

[Embodiment] In the above description, the container portion 4 has been described as a part of the container body 1 for accommodating the hollow fiber membrane module, but it may be a shrinkable container 14 different from the container body 1 as shown in FIG. Further, the liquid passage 10 from the container body 1 to the third valve means 9 itself may be a contraction container. At this time, stronger backwashing is performed by providing external biasing means 15 from the outside to the inside with respect to the retained filtrate such as the container part 4, the contraction container 14 and / or the liquid passage 10. be able to. The external biasing means 15 can be performed by a known pressurizing method such as pneumatic pressure, hydraulic pressure and hydraulic pressure.

FIG. 5 shows a structure in which the container portion and the liquid flow passage are formed of a rigid body, and a backwash pressure is applied by a pressure tank provided in a branch pipe branched from the liquid flow passage by the contraction function of these members. FIG. Further, FIG. 6 is a diagram for explaining the operation, FIG. 6 (a) is a diagram showing a case during the filtering operation, and FIG. 6 (b) is a diagram for backwashing the hollow fiber membrane. It is contrasted with 2. A description of members having the same functions as those of the embodiment shown in FIG. 1 will be omitted.

In FIG. 5, a pressure pressurizing tank 19 is provided which communicates with a branch pipe 20 branched from the liquid passage 10. A valve 21 which is openable to the atmospheric pressure is provided above the pressure tank 19 via a sterilization device 22 including a filter for removing various germs and the like invading from the atmosphere. With this configuration, during the operation stop period, the valve 21 is opened and the position of the pressure tank 19 is adjusted up and down so that the air remains above the pressure tank 19 and the filtrate remains below the pressure tank 19 in an equilibrium state. Preferably a pressure tank 19
It is preferable that 80 to 90% of the air be filled with air. In this state, the valve 21 is closed.

When the filtering operation is performed in this state, as shown in FIG.
In the filtering operation shown in (a), the air in the pressure tank 19 is compressed by the liquid pressure of the filtrate flowing through the liquid passage 10, and the water surface 23 moves upward in the pressure tank 19. That is, the compressive force is stored in the air.

Now, when the first valve means 7 and the third valve means 9 are closed and the second valve means 8 is opened to the backwash state, the compressive force stored in the air is released. To be done. Therefore, the water surface 23 is pushed down in the direction of the arrow by the force corresponding to this opening pressure, and the residual filtered water in the container portion 4, the liquid passage 10 and the pressure tank 19 flows out from the second valve means 8, so that it is hollow. It is possible to return the blockages in the pores of the thread membrane from the pores to the supply side, and also to remove the substance blocked at the pore inlets.

That is, it is possible to apply pressure during backwashing without using elastic members in the container portion and the liquid passage.

In the present invention, the case where the hollow fiber membrane filtering device is constituted alone has been described. However, it is general to use the hollow fiber membrane filtering device as a part of a liquid treatment device such as a water treatment device. That is, a pretreatment device for sand filtration or activated carbon may be provided on the supply side of the hollow fiber membrane filtration device.
A water reforming device such as an electrolyzed water generator or a reverse osmosis membrane or a post-treatment device may be provided behind the valve means. These are set freely according to the use of the liquid.

The hollow fiber membrane filtering device thus constructed can be operated as maintenance free in a long-term use.

[0034]

As described above, according to the present invention, not only the suspended matter adhering to the membrane surface of the hollow fiber membrane is removed, but also the liquid pressure accumulating the minute substance blocking the microtube is applied from the passage side of the membrane. Since the backwashing is performed by applying pressure, not only the chemicals or chemicals such as compressed air and additional devices are not used, but also the cleaning time can be relatively shortened.

It is possible to stably and safely remove the substance that blocks the fine tube without using a special flow tube operation, and it is easy to maintain and highly economical.

[Brief description of the drawings]

FIG. 1 is an example showing the configuration of a hollow fiber membrane filtration device in which the present invention is implemented.

FIG. 2 is a diagram for explaining the operation of the hollow fiber membrane filtration device according to the present invention.

FIG. 3 is a diagram in the case of controlling the empty fiber membrane filtering device of the present invention by providing a control unit.

FIG. 4 is another embodiment showing the configuration of the hollow fiber membrane filtration device in which the present invention is implemented.

FIG. 5 is another embodiment showing the configuration of the hollow fiber membrane filtration device in which the present invention is implemented.

FIG. 6 is a view for explaining the operation of another embodiment showing the configuration of the hollow fiber membrane filtration device in which the present invention is implemented.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container body 2 Hollow fiber membrane module 4 Container part 7 1st valve means 8 2nd valve means 9 3rd valve means 11 Control part 12 CPU 14 Shrink container 15 Energizing means 19 Pressure tank

Claims (5)

[Claims] 1. A filtering device for accommodating a hollow fiber membrane module in a container body, wherein at least a part of a container body and a liquid passage pipe constituting a hollow fiber membrane passage side of a filtrate swell with a pressure of the filtrate liquid. The first valve means for controlling the supply liquid and the waste liquid in the container body are discharged to the input side of the container body for supplying the liquid to the hollow fiber membrane, and the discharge liquid is discharged from the container body. Hollow fiber membrane filtration device, characterized in that it is provided with a second valve means for controlling the fluid flow rate, and is provided with a third valve means or a pressure closing means having an equivalent effect on the liquid passage side of the urging structure. . 2. The hollow fiber membrane filtration device according to claim 1, further comprising external urging means directed from the outside to the inside of the urging structure. 3. The hollow fiber membrane filtering device according to claim 1, wherein the urging structure comprises a pressure tank communicating with the liquid passage, and the pressure tank has means for accumulating the pressure of the filtrate. A hollow fiber membrane filtration device characterized by the following. 4. The hollow fiber membrane filtration device according to claim 1, wherein the filtrate is an aqueous solution, and the pressure is a supply water pressure. 5. The hollow fiber membrane filtering device according to claim 1, claim 2, claim 3 or claim 4, wherein the first and third valve means are closed for a predetermined time or by a detection signal of the detection means. At the same time, the second valve means is opened, and backwashing is carried out with the accumulated pressure of the urging structure, whereby a method for removing contaminants from the hollow fiber membrane filtration device.