JPH10323544A - Backwashing device for hollow yarn membrane filtration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To backwash and remove a fine material clogging a hollow yarn membrane fine tube and suspended matter deposited on the membrane surface from the passing side of the membrane by a pressurized and accumulated air pressure. SOLUTION: A vessel body 1 is provided with a first valve means 7 and a second valve means 8 in the side part and in the bottom part on the liquid supply side therof respectively. Further, a liquid flow passage 10 extends from a vessel part 4 and communicates with a lower part 11 of a pressure tank 13. An upper part 12 of the pressure tank 13 is provided in series with an air valve 14 communicating with an air pump 16. Moreover, a liquid flow passage 17 is provided from a projected tip 20 in the central part of the pressure tank 13. The upper part 12 of the pressure tank 13 is made to an air reservoir 19 for air forcibly fed from an air pump 16. The liquid flow passage 17 is provided with a third valve means 9 whose the tip is made to a liquid discharge port 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber filtration device, and more particularly to an improvement of a backwashing device suitable for removing contaminants in a hollow fiber filtration device.

[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 filtering material is constituted by a large number of fine holes opened inside and outside of a thin tube having a fibrous form, and can have a large filtering area. Since it is as fine as 2 μ, it is possible to prevent the passage of substances containing microscopic substances and bacteria. For this reason, it is particularly suitably used as a filtering material for water purifiers for the purpose of filtering drinking water. The hollow fiber membrane used for this type of filtration is a small-sized apparatus, and in order to have a large filtration area, a bundle of several hundreds to several tens of thousands of thread-shaped flexible thin tubes is folded back into a U-shape. Alternatively, the hollow fiber membrane module is made linear and fixed at its ends with an adhesive, that is, the hollow fiber membrane module is housed in a container or the like for use.

[0003] The hollow fiber filtration material can remove suspended substances and water from the water by the micropores as described above, but in the long-term use, the microparticles to be filtered enter the micropores and become blocked. For this reason, the hollow fiber filtration material is frequently replaced or washed, etc., and the solid content clogged in the micropores, and at the time of filtration, reaches the micropore inlet according to running water, and the diameter becomes larger than the micropore diameter. It is necessary to frequently remove organic substances including inorganic substances and bacteria deposited on the surface, and to secure a sufficient amount of filtered water. 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.

[0005] In the apparatus disclosed in Japanese Patent Application No. 8-017098 of the same applicant, fine substances closing the hollow fiber membrane microtubules and suspended matter adhering to the membrane surface were accumulated under tap water pressure without using chemicals or the like. Removed by liquid pressure. In this case, the liquid pressure is increased from the passage side of the membrane, so that the liquid is backwashed in the filtration direction. With this operation, not only the suspended matter adhering to the membrane surface but also the substance that closes the fine tube can be removed without performing a special flow tube operation.

[0006]

However, in the above-described apparatus, in actual use, if the water pressure of raw water is low, air pressure may not be increased by water pressure as necessary to remove clogging substances. Therefore, the present invention provides an air pump to the pressurized tank of the above-described apparatus, in which air is supplied to the pressurized tank, the air pressure in the air reservoir in the pressurized tank is set to a predetermined pressure, and then the backwashing operation is performed. By extruding the liquid with the above air pressure, the hollow fiber membrane microtubes are forcibly washed by strong backflow.

It is another object of the present invention to provide a suitable hollow fiber membrane filtration backwashing apparatus which is easy to install and maintain and is economical.

[0008]

According to a first aspect of the present invention, there is provided a hollow fiber membrane filtration backwashing apparatus for controlling a supply liquid to a liquid supply side of a container housing a hollow fiber membrane module. Means and a second valve means for discharging the waste liquid, wherein a pressure tank is provided through a liquid passage on the side of the filtrate passing through the hollow fiber membrane, and the liquid passage is in communication with a lower portion of the pressure tank. An air reservoir is provided above the pressure tank. The air reservoir communicates with an air pump via an air valve, and a third valve means is provided in a liquid passage protruding to a position inside the pressure tank. The method is characterized in that backflow cleaning is performed with pressurized air in the air reservoir while opening and closing the first valve means, the second valve means, and the third valve means.

In the backflush apparatus for hollow fiber membrane filtration according to a second aspect of the present invention, prior to the backflow cleaning, pressurized air of a constant pressure is introduced into an air reservoir, an air valve is closed, and then the inside of a pressure tank is removed. Backwash with pressurized air.

[0010]

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

In FIG. 1, reference numeral 1 denotes a container body, and 2 denotes a hollow fiber membrane module in which one end of a hollow fiber bundled in a U-shape is fixed with a resin 3 and the U-shaped side is housed in the container body 1 as a liquid supply side. I have. 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 where the filtrate is collected. The container body 1 has a hermetically sealed structure, and has openings 5 and 6 at its liquid supply side at the side and bottom, respectively, and a first valve means 7 and a second valve means 8 at each of the openings. Is provided. A liquid passage 10 extends from the container 4 and communicates with the lower portion 11 of the pressure tank. In the upper part 12 of the pressure tank, an air valve 14 communicating with an air pump 16 is provided in series with a sterilization device 15 composed of a filter for removing various bacteria and the like invading from the atmosphere. A liquid passage 17 is formed at the center of the pressure tank 13 to form a protruding tip 20. An upper part of the pressure tank forms an air reservoir 19 for air press-fitted from an air pump 16. A third valve means 9 is provided in the liquid passage 17, and the tip of the third valve means 9 is a discharge port 18.

FIG. 2 is a view for explaining the filtering operation and the cleaning operation of the hollow fiber membrane surface of the hollow fiber membrane filtration device in which the present invention is carried out. FIG. FIG. 2B is a diagram in the case of cleaning the surface of the hollow fiber membrane. The description of the same configuration as the embodiment shown in FIG. 1 is omitted.

In FIG. 2A, the first valve means 7
Is opened, the second valve means 8 is closed,
The third valve means 9 is opened. The air valve 14 is closed. In this state, for example, when tap water is supplied from the first valve means 7 to the hollow fiber membrane module in the direction indicated by the arrow, the tap water is filtered by the hollow fiber membrane by the pressurized pressure of the tap water, and the fine pores are formed. To the container part 4, enters the lower part 11 of the pressure tank from the liquid passage 10, and protrudes into the center part of the pressure tank 13 while compressing or flowing out the air remaining in the upper part of the pressure tank 13. It reaches the projecting tip 20 of the liquid passage 17 and flows to the liquid discharge port 18 via the third valve means 9.

As shown in FIG. 2B, the third valve means 9 and the air valve 14 are closed and the first valve means 9 is closed.
By opening the valve means 7 and the second valve means 8 and allowing water to flow from the first valve means 7 to the second valve means 8, it is possible to clean the substance clogged at the pore inlet. In the above description, the first valve means 7 has been described as a tap water supply side, and the second valve means 8 has been described as a drainage side. Conversely, the second valve means 8 has a tap water supply side, and the first valve means 7 has a drain valve. It can be the drain side.

FIG. 3 is a diagram showing an embodiment in which the hollow fiber membrane is backwashed. FIG. 3A shows a state in which flowing water is stopped prior to backwashing, and the first valve means 7, the second valve means 8,
The third valve means 9 and the air valve 14 are all closed. When the backwash is instructed, as shown in FIG. 3B, the air valve 14 is opened, the air pump 16 operates, and air is supplied to the pressure tank 13. As a result of the first valve means 7, the second valve means 8 and the third valve means 9 being all closed, the pressure of the air in the air reservoir 19 increases. At this time, the air reservoir 16 is moved from the air pump 16 to the air reservoir 19.
The pressure of the air flowing into the space is adjusted so that it is limited to the space occupied by the pressure tank upper portion 12 from the projecting end 20 of the liquid passage 17. In other words, because the pressure is constant,
The amount of pressurized air is limited to the space. Then, FIG.
As shown in (c), when the air valve 14 is closed, the operation of the air pump 16 is stopped, and the second valve means 8 is opened, the water in the pressure tank 13 is caused by the pressure of the air in the air reservoir 19. Part of the liquid flows back through the liquid passage 10 and flows back through the container 4 into the micropores of the hollow fiber membrane.
From the valve means 8 in the direction indicated by the arrow. At this time, since the water flow instantaneously reverses with the air pressure of the pressure tank, the obstruction in the pores is returned from the pores to the supply side. In addition, substances clogged at the pore entrance can be removed. The amount of backwash water is the height in the tank where the air pressure from the projecting tip 20 is balanced.

For this reason, preferably, as shown in FIG. 3D, the second valve means 8 is closed, the air valve 14 is opened, the air pump 16 is operated again, and air is supplied to the pressure tank 13. I do. The liquid inside the pressure tank 13 flows by the backwashing shown in FIG. 3C, and more air is stored in the pressure tank 13 than in FIG. be able to. Thereafter, as shown in FIG. 3E, backwashing similar to that shown in FIG. 3C is performed. This backwash water amount is the height m− in the tank where the air pressure from the projecting tip 20 is balanced. A predetermined pressure air is stored in the air reservoir 19 by the air supply to the pressure tank 13 by the air pump 16, but the air valve 14 is always closed before the backwash. Thus, there is no possibility that the backwash liquid at a predetermined pressure flows during backwash and the hollow fiber module 2 is damaged.

Next, as shown in FIG. 3F, the second valve means 8 and the third valve means 9 are closed, and the first valve means 7 is opened to supply water. As a result, the air inside the pressure tank 13 is compressed by the water pressure of the filtered feed water, and the water level in the tank rises in the upper part of the pressure tank 1.
Move in two directions. That is, the compressive force is stored in the air. Next, as shown in FIG. 3 (g), the first valve means 7 and the third valve means 9 are closed and the second valve means 7 and the second valve means 9 are closed.
By opening the valve means 8, the air compressed by the water pressure is released. Therefore, the surface of the water is pushed down in the direction of the arrow by a force corresponding to the opening pressure, and the container portion 4,
The residual filtered water in the flow passage 10 and the pressure tank 19 is
Of the hollow fiber membrane can be cleaned. Then, as shown in FIG. 3 (h), the first valve means 7 is opened and the surface of the hollow fiber membrane module is washed, that is, the substance blocked at the pore inlet shown in FIG. 2 (b) is washed. . Thereafter, as shown in FIG. 3 (i), the second valve means 8 is closed, and the third valve means 9 is opened, so that excess air in the air reservoir 19 is discharged.

The opening and closing of each valve means can be performed manually as a manual operation. Preferably, the opening and closing of each valve is electrically driven, and as shown in FIG. Can be provided. For example, when filtration is completed and backwashing is instructed, the first valve means 7, the second valve means 8 and the third valve means 9 are closed in conjunction with each other, and at the same time, the air valve 14 is opened, and the air valve 14 is opened. The pump 16 is driven to supply air to the pressure tank 13.
As a result, the state shown in FIG. 3B is performed together with the control of the control unit, and the backwash is performed reliably. These operations are performed by the MPU 22 that constitutes the control unit 21 and the ROM 23 that stores the opening information of the halves.

The control by the MPU 22 shown in FIG. 4 can be performed based on a signal from a sensor disposed in a container or the like, as described above, in addition to using the control information stored in the ROM 23. it can. That is, due to the increase in the contamination resistance of the hollow fiber membrane, the supply liquid side pressure sensor 24
If the pressure of the pressure sensor 25 disposed in the liquid passage 10 does not increase as compared with the above, it is assumed that the hollow fiber membrane is closed, and the backwash can be performed each time as described above. Further, it is also possible to perform control to separately process each signal, or to perform a calculation based on a sum, a difference, a product, or the like of each signal and output a control signal to secure an optimal flow rate.

FIG. 5 is another embodiment showing the configuration of a backwashing apparatus for hollow fiber membrane filtration in which the present invention is carried out. The description of the same configuration as the embodiment shown in FIG. 1 is omitted.

In FIG. 5, a pressure tank 13-1 which forms a liquid passage 10-1 extending from the container part 4 and communicates via a branch pipe 26 branched from the liquid passage 10-1.
Is provided. An air valve 14 that can be freely opened to the atmospheric pressure is provided directly above the pressure tank 13-1 via an antibacterial device 15 composed of a filter that removes various bacteria and the like invading from the atmosphere. The third valve means 9 is provided in the liquid passage 10-1 after the branch pipe 26 branches. With this configuration, the same operation as that shown in FIG. 1 can be performed.

In the present invention, the case where the hollow fiber membrane filtration device is constituted alone is described. However, the hollow fiber membrane filtration device is generally used as a part of a liquid treatment device such as a water treatment device. That is, a pretreatment device such as sand filtration or activated carbon may be provided on the supply side of the hollow fiber membrane filtration device, and a water reforming device such as an electrolyzed water generator or a reverse osmosis membrane is provided behind the discharge port. A post-processing device may be provided. These are set freely according to the use of the liquid.

The backwashing device of the hollow fiber membrane filtration constructed as described above can be operated as maintenance-free in long-term use.

In the present invention, the liquid to be filtered may be any liquid that is filtered through a hollow fiber membrane, regardless of hydrophilic or lipophilic liquid, and is particularly suitable for filtering drinking water.

[0025]

As described above, according to the present invention, not only the suspended matter adhering to the surface of the hollow fiber membrane is removed, but also the pressure of the liquid that has accumulated the fine substance that closes the microtubule is applied from the passage side of the membrane. It is safe because it does not use chemicals or related additional equipment. In addition, since the maximum pressure of the air for promoting backwashing is regulated, the backwash always flows at a predetermined pressure and does not damage the hollow fiber module, but also relatively shortens the washing time. be able to.

The removal of the substance that blocks the fine tube can be performed stably and safely without using a special flow tube operation, and maintenance is easy and economical.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a filtration operation and a cleaning operation of the surface of the hollow fiber membrane of the hollow fiber membrane filtration device according to the present invention.

FIG. 3 is a diagram illustrating a backwash operation of a backflush apparatus for hollow fiber membrane filtration in which the present invention is implemented.

FIG. 4 is a diagram showing a case where the backwashing apparatus for hollow fiber membrane filtration of the present invention is controlled by a control unit.

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

[Explanation of symbols]

 Reference Signs List 1 container body 2 hollow fiber membrane module 7 first valve means 8 second valve means 9 third valve means 10 liquid passage 13 pressure tank 14 air valve 16 air pump 17 liquid passage 19 air reservoir 21 control Part 22 MPU

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[Procedure amendment]

[Submission date] July 17, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a filtration operation and a cleaning operation of the surface of the hollow fiber membrane of the hollow fiber membrane filtration device according to the present invention.

FIG. 3-1 is a diagram for explaining a backwashing operation of a backwashing device for hollow fiber membrane filtration according to the present invention.

FIG. 3-2 is a diagram illustrating a backwashing operation of a backwashing apparatus for hollow fiber membrane filtration in which the present invention is implemented.

FIG. 3-3 is a diagram illustrating a backwashing operation of a backwashing device for hollow fiber membrane filtration in which the present invention is implemented.

FIG. 4 is a diagram showing a case where the backwashing apparatus for hollow fiber membrane filtration of the present invention is controlled by a control unit.

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

DESCRIPTION OF REFERENCE NUMERALS 1 container body 2 hollow fiber membrane module 7 first valve means 8 second valve means 9 third valve means 10 liquid passage 13 pressure tank 14 air valve 16 air pump 17 liquid passage 19 air reservoir 21 control unit 22 MPU

Claims (2)

[Claims] 1. A hollow fiber membrane for a filtrate, comprising: a first valve means for controlling a supply liquid and a second valve means for discharging a waste liquid, on a liquid supply side of a container housing a hollow fiber membrane module. A pressure tank is provided on the passage side through a liquid passage, the liquid passage communicates with a lower portion of the pressure tank, and an air reservoir is provided above the pressure tank, and the air reservoir is provided with an air valve. A third valve means is provided in a liquid passage which protrudes to a middle position in the pressure tank through the air pump, and the first valve means, the second valve means, and the third valve means are connected to each other. A backwashing device for hollow fiber membrane filtration, wherein backflow washing is performed with pressurized air in the air reservoir while opening and closing. 2. The method according to claim 1, wherein prior to said backwash, pressurized air of a constant pressure is introduced into the air reservoir, the air valve is closed, and the backflow is washed with the pressurized air in the pressure tank. A backwashing apparatus for the hollow fiber membrane filtration according to the above.