JP2000342935A - Filter apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly wash the surface of a membrane, in a filter apparatus for filtering water to be treated by using a plurality of membrane filter screens, by providing an air discharge means under the filter screens and providing rectifying guides outside the filter screens positioned at the outermost parts. SOLUTION: In the filtering treatment of water to be treated, water to be treated is introduced into a chamber 16 from a supply port 5 to be transmitted through the hollow-fiber yarn membranes of a hollow-fiber yarn membrane knitted fabric constituting each of filter screens 1. When the filter screens 1 are washed, the supply of water to be treated is stopped and an air outlet 10 is opened in such a state that the chamber 16 is filled with water to be treated and scrubbing air is supplied from an air supply port 8 to be ejected to the roots parts of the filter screens 1 by an air discharge means 9 through an air passage 17 and an air pipe 13. The ejected scrubbing air rises while washes the surface of the hollow-fiber yarn membrane knitted fabric to be discharged from the air outlet 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is suitable for filtration of highly polluting liquids such as filtration of river water and lake water, filtration of industrial water, and wastewater treatment, as well as higher-order treatment after sand filtration in water purification treatment. The present invention relates to a filtration device that can be used for a filter.

[0002]

2. Description of the Related Art Filtration devices using hollow fiber membranes are made of sterile water,
Used in the field of microfiltration such as production of high-purity water and drinking water and purification of air, and in the field of secondary and tertiary treatment in sewage treatment plants and in the field of highly polluting water treatment such as solid-liquid separation in septic tanks. Has also been applied. As a hollow fiber membrane module used for a filtration device used for high-pollutant water treatment, a hollow fiber membrane knitted fabric was spread in a screen shape, and one end or both ends of the hollow fiber membrane were fixed to a frame while being kept open. A flat hollow fiber membrane module has been proposed. In a flat hollow fiber membrane module, a filtration operation is often performed by suctioning the secondary side of the filtration membrane. For example, Japanese Patent Application Laid-Open No. Hei 9-1410
In Japanese Patent Publication No. 66, a membrane separation device is immersed in a treatment tank,
A membrane separation device for filtering a liquid to be treated by suction filtration is described. However, in general, such a suction filtration method has disadvantages such as low filtration speed and low treatment efficiency.In order to increase the filtration speed, the membrane module is housed in a pressure-resistant container such as a cylindrical container, and the filtration membrane is used. The primary side must be pressurized and filtered.

[0003] However, when the flat hollow fiber membrane module is housed in a cylindrical container and used as a filtration device, the proportion occupied by portions other than the hollow fiber membrane increases, resulting in poor volumetric efficiency. The cost of the container becomes higher, for example, a reinforcing member is required to obtain a pressure-resistant structure. Also, by arranging a plurality of flat hollow fiber membrane knitted fabrics in parallel or folding them in a zigzag shape to form a hollow fiber membrane module, and performing scrubbing with air supplied from the air header, a long-term high filtration function is achieved. A filter device that can be maintained has been proposed in Japanese Patent Application Laid-Open No. 09-141063.

[0004]

However, in such a filtering apparatus, the supplied air is difficult to flow uniformly between the hollow fiber membranes and knitted fabrics, causing a drift or a plurality of air bubbles during rising. Sometimes they came together and rose as big bubbles. In addition, since the entire surface of the hollow fiber membrane is not washed due to this phenomenon, it has not been possible to sufficiently achieve a uniform recovery of the filtration function, or it has been necessary to supply more air than necessary.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem, and it is an object of the present invention to provide a filter device having a plurality of filter screens disposed in a can body for scrubbing. An object of the present invention is to provide a filtration device capable of uniformly cleaning the membrane surface by efficiently supplying air to a filtration screen. That is, the gist of the present invention is a filtration device that performs filtration of water to be treated by using a filtration screen having a plurality of membranes. There is provided a pressurized filtration device characterized in that a rectifying guide is provided on the outside. When the filtration screen is provided with a plurality of hollow fiber membranes, the filtration can be performed at a high processing speed. If the rectifying guide is plate-shaped and provided in parallel with the sheet surface of the filtration screen, the cleaning efficiency by aeration increases. If at least a part of the lower end of the rectifying guide is bent to the side opposite to the filtration screen, the cleaning efficiency increases. The length of the rectification guide is 1 of the filtration screen length
When it is 0% to 90%, the cleaning efficiency increases.

[0006] Also, a plurality of filtration screens, an upper fixing member, a lower fixing member for fixing both ends of the hollow fiber membranes constituting the filtering screen while maintaining the open state, and air provided above the lower fixing member. A discharging means, a gas passage for supplying air to the air discharging means, an element cap forming a lower treatment water chamber on a lower end opening side of the hollow fiber membrane of the lower fixing member, and an upper end opening side of the hollow fiber membrane of the upper fixing member. The filtration device having a cap that forms the upper treated water chamber, a water guide pipe that communicates the upper treated water chamber and the lower treated water chamber, and a pipe that houses members other than the cap has excellent volumetric efficiency. Also, the membrane cleaning efficiency is excellent.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic sectional view showing an example of the filtration device of the present invention. This filtering device is a can 3
A filter screen 1 in which a plurality of hollow fiber membranes are fixed in a sheet shape is disposed in parallel in a container formed by a filter 4 and a cap 4 at predetermined intervals. In the present embodiment, a hollow fiber membrane knitted fabric is used for the filtration screen, and the upper end and the lower end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric are maintained in an open state, and the upper fixing member 2b and the lower part are fixed. Each is fixed to the fixing member 2a. An upper treated water chamber 14 is formed in a space between the hollow fiber membrane opening side of the upper fixing member 2b and the cap 4, and a lower treated water chamber 15 is formed between the hollow fiber membrane opening side of the lower fixing member 2a and the element cap. 11 is formed in the space.

[0008] Between the two fixing members, there is provided a water guide pipe 12 which penetrates these fixing members and is arranged in the up-down direction and communicates between the upper treated water chamber 14 and the lower treated water chamber 15.
The treated water in the lower treated water chamber 15 is guided to the upper treated water chamber 14 by the water conduit 12, and is finally taken out of the filtration device from the treated water outlet 6. The upper fixing member 2b has a brim-shaped portion having a diameter larger than the inner diameter of the can body 3, and the flange portion between the can body 3 and the cap 4 is sandwiched with the brim-shaped portion of the upper fixing member. , The whole is fixed. And the air supply port 8 is opening in the side surface of the brim-shaped part, and the air supply port 8
A tubular gas passage 1 having an opening on the lower fixing member 2a side
It communicates with 7. The introduced air is supplied to the air pipe 13
And reaches the air discharging means 9 provided above the lower fixing member 2a. The air discharging means 9 has a slit-shaped through-hole having a large number of air discharge holes, and each filtration screen is inserted into this through-hole.

Above the air discharging means 9, a plurality of plate-shaped rectifying guides 18 are provided in parallel with the filtration screen. The rectifying guide has a lower end bent opposite to the filtration screen. The rectifying guide 18 can be fixed to the water pipe 12 or the air discharging means 9. Also,
The can body 3 is provided with a treated water supply port 5 and a sediment outlet 7 below the can body 3, and an air outlet 10 for discharging air from the diffuser pipe to the outside of the can body is provided above the can body 3. Also, cap 4
Is provided with a treated water outlet 6.

FIG. 2 is a sectional view showing another example of the filtration device of the present invention. In FIG. 2, the illustration of the tube and the cap is omitted. In this embodiment, two rectifying guides 18 are provided above the air discharging means 9 and on both outer sides of the outermost filtration screen 1 made of a hollow fiber membrane knitted fabric. The rectifying guide 18 is fixed to the water pipe by a rectifying guide fixing member 19.

FIG. 3 is a sectional view of the filter element shown in FIG.
It is sectional drawing of the surface cut | disconnected by. The air discharging means 9 has a hollow portion 21 inside, and the air supplied from the air pipe 13 passes through the hollow portion 21 and scatters from a plurality of air discharge holes 20 provided on the side surface inside the slit 22. I'm bothered. The root portion of each filtration screen 1 is inserted into each slit 22.

The filtration of the water to be treated in the filtration apparatus shown in FIGS. 1 to 3 can be performed, for example, as follows.
First, the sediment outlet 7 and the air outlet 10 are closed by a suitable means such as a valve, and the water to be treated is pressurized and introduced into the water chamber 16 through the water supply port 5. The to-be-treated water introduced into the to-be-treated water chamber 16 comes into contact with the outer surface side of the hollow fiber membrane in the hollow fiber membrane knitted fabric constituting the filtration screen 1, and the treated water permeates into the hollow fiber membrane. The solid is filtered. The filtered treated water flows from the hollow part of the hollow fiber membrane to the lower treated water chamber 14 and the upper water collecting chamber 15. The treated water in the treated water chamber 15 is guided to the treated water chamber 14 via the water guide pipe 12, and is finally taken out of the filtration device from the treated water outlet 6.

The washing operation of the filtration screen 1 can be performed, for example, as follows. After performing the filtration treatment for a predetermined time, the supply of the water to be treated is stopped, and the water outlet 10 is filled with the water to be treated in the water chamber 16.
Is released, and then the air for scrubbing is supplied from the air supply port 8. The supplied air passes through the gas passage 17 and the air pipe 13 and is jetted toward the root of each filter screen 1 by the air discharging means 9. The jetted scrubbing air forms bubbles and rises between the filtration screens 1 while washing the surface of the hollow fiber membrane knitted fabric constituting the filtration screen 1, and is discharged out of the system from the air outlet 10.

The scrubbing air supplied to the outside of the two outermost filtration screens among the arranged plurality of filtration screens 1 causes a hollow fiber to flow between the filtration screen 1 and the rectifying guide 18. It rises while cleaning the outer surface of the membrane, and is similarly discharged from the air outlet 10 to the outside of the system.

[0015] It is preferable to use a hollow fiber membrane knitted fabric for the filtration screen used in the present invention. As the hollow fiber membrane constituting the hollow fiber membrane knitted fabric, polyolefin-based, cellulose-based, polyvinyl alcohol-based, polysulfone-based, polymethyl methacrylate-based and other various materials and composites thereof can be used, An olefin-based hollow fiber membrane such as polyethylene having high strength and high elongation is preferably used in view of knitting and weaving properties of the knitted fabric and coping with shaking caused by air for scrubbing. Further, as long as the hollow fiber membrane can be used as a filtration membrane, the pore diameter, porosity, film thickness, outer diameter and the like are not particularly limited. Hollow fiber membrane knitted fabric, any knitting method, as long as the function of the hollow fiber membrane as a filtration membrane is maintained,
It may be based on a weaving method.

[0016] The hollow fiber membrane knitted fabric is developed into a screen to form a filtration screen, and a plurality of the screens are arranged on the upper fixing member and the lower fixing member so as to be parallel. The pitch between each filtration screen is preferably 3 to 50 mm, and 5
-20 mm is more preferable. At a pitch of 3 mm or less,
At the time of discharging the sediment after scrubbing, for example, there is a tendency that solids peeled off from the side surface of the hollow fiber membrane are caught between the filtration screens and the probability of remaining there is high.
At a pitch of 0 mm or more, the total membrane area of the hollow fiber membrane that can be stored in the tube tends to decrease.

The upper fixing member and the lower fixing member fix the respective hollow fiber membranes constituting the filtration screen and function as members for separating treated water and treated water without leakage. For example, urethane resin, epoxy resin, It can be formed of an unsaturated polyester resin or the like. The fixing of each hollow fiber membrane to these fixing members can be performed by a conventional method.

The element cap can be made of a material such as resin or metal in consideration of pressure resistance, water resistance, corrosion resistance, elution resistance, etc., and is bonded to the lower fixing member 2a or Fix liquid-tight using a ring or the like. The water pipe can be made of a material such as resin, metal, etc. in consideration of pressure resistance, water resistance, corrosion resistance, elution resistance, adhesiveness with a fixing member, etc., according to the amount of liquid to be treated. The hole diameter and the number of the holes are selected for convenience.

The air release means 9 can be made of a material such as resin or metal in consideration of pressure resistance, water resistance, corrosion resistance, workability, etc., and its fixing position is good cleaning effect by scrubbing. Can be obtained, for example, above the lower fixing member 2a. Various fixing means can be used to fix the position of the air discharging means 9. As shown in the figure, a method of fixing the position of the air discharging means 9 through a fixing part with the water pipe 12 is based on the structure of the element. Is preferred for simplifying

The rectifying guide can be made of a material such as resin or metal in consideration of water resistance, corrosion resistance, mechanical strength against vibration, and the like, and the width thereof is equal to or slightly wider than the filtration screen, and is preferable. . If the width is narrower than the filtration screen, the air for scrubbing escapes from the side of the straightening guide,
In some cases, both sides in the longitudinal direction of the hollow fiber membrane constituting the filtration screen cannot be sufficiently washed. There is no particular limitation on the thickness of the flow guide. The length of the rectifying guide is 10% of the length of the filtration screen, that is, the length of the hollow fiber membrane when a hollow fiber membrane is used as the separation membrane, that is, the distance between the lower fixing member and the upper fixing member in this embodiment. It is preferably 90%. If it is shorter than 10%, the rectifying effect to scrubbing air tends to be reduced, and if it is longer than 90%, stagnation of scrubbing air occurs near the lower fixing member side of the upper fixing member, and the hollow fiber membrane in the portion concerned Surface cleaning tends to be insufficient.

The rectifying guide has a length corresponding to substantially the entire distance between the lower fixing member and the upper fixing member, and a slit or a notch is provided at least in a portion near the upper fixing member side of the rectifying guide. It may be. In this case, the opening area of the slit or notch is
It is set so as to be 10% or more of the entire area of the rectifying guide. 10% opening area of slit or notch
If the amount is smaller than that, the scrubbing air stays near the lower fixing member side of the upper fixing member, and the surface of the hollow fiber membrane in the portion tends to be insufficiently cleaned.

The rectifying guide preferably has a structure in which a part of the lower end is bent to the opposite side to the filtration screen 1 as shown in FIGS. With such a configuration, it is possible to prevent the scrubbing air from going around the outside of the rectifying guide (the side opposite to the side facing the filtration screen 1), thereby preventing the scrubbing air from being effectively used.

Since the scrubbing air jetted from the outermost air discharge hole is easily separated from the filter screen immediately after jetting, the straightening guide can be fixed above the air discharging means to prevent this. preferable. The rectification guide may be fixed to the water pipe by a rectification guide fixing member as shown in FIG. 2, or may be fixed from an air discharging means, a lower fixing member or an upper fixing member,
In any case, it is preferable to fix to any one of the filtration element constituent members from the viewpoint of workability when replacing the filtration element. As a fixing method, it can be performed by a conventional method such as screwing, fitting, adhesion, fusion and the like. Further, it is preferable that the rectifying guide is fixed so as to be substantially parallel to the filtration screen. When the parallelism is impaired, there is a tendency that there is a difference in detergency between a wide portion and a narrow portion between the filter screen.

[0024] The can body and the cap are preferably formed in a cylindrical shape in order to ensure pressure resistance, and are made of a material such as resin or metal in consideration of pressure resistance, water resistance, corrosion resistance, elution resistance and the like. Is preferred. Further, the can body may have a structure that can be separated at an appropriate portion.

[0025]

According to the filter apparatus of the present invention, the air for scrubbing can be reliably and uniformly supplied between the filter screens, and the outer surface of the outermost filter screen can be scrubbed accurately. Therefore, the filtration screen can be washed uniformly and efficiently, and high filtration efficiency can be maintained over a long period of time.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a filtration device of the present invention.

FIG. 2 is a schematic cross-sectional view showing one example of a filtration device of the present invention.

FIG. 3 is a schematic sectional view of the filtration device shown in FIG. 2;

[Explanation of symbols]

 1. Filtration screen 2a. Lower fixing member 2b. Upper fixing member 3. 3. Can body Cap 5. Supply port for treated water 6. 6. Treated water outlet 7. Sediment exit Air supply port 9. Air release means 10. Air outlet 11. Element cap 12. Water pipe 13. Air tube 14. Upper treated water chamber 15. Lower treated water chamber 16. Treated water chamber 17. Gas passage 18. Rectification guide 19. Straightening guide fixing member 20. Air discharge hole 21. Hollow part 22. slit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/44 C02F 1/44 K

Claims (6)

[Claims] Claims 1. A filtration device for filtering water to be treated using a filtration screen having a plurality of membranes, wherein an air discharging means is provided below the filtration screen, and outside of the outermost filtration screen, A pressurized filtration device provided with a rectifying guide. 2. The pressurized filtration device according to claim 1, wherein the filtration screen is provided with a plurality of hollow fiber membranes. 3. The pressurized filtration device according to claim 1, wherein the rectifying guide has a plate shape and is provided in parallel with a sheet surface of the filtration screen. 4. The pressurized filtration device according to claim 1, wherein at least a part of a lower end of the rectifying guide is bent to a side opposite to the filtration screen. 5. The length of the straightening guide is 10% to 90% of the length of the filtration screen.
The pressurized filtration device according to any one of claims 4 to 7. 6. A plurality of filtration screens, an upper fixing member, a lower fixing member for fixing both ends of the hollow fiber membranes constituting the filtering screen while maintaining an open state, and air provided above the lower fixing member. Discharging means, a gas passage for supplying air to the air discharging means, an element cap forming a lower treated water chamber on the lower end opening side of the hollow fiber membrane of the lower fixing member, and an upper end opening side of the hollow fiber membrane of the upper fixing member The filtration according to any one of claims 1 to 5, further comprising a cap that forms an upper treated water chamber, a water guide pipe that communicates the upper treated water chamber and the lower treated water chamber, and a tube that stores members other than the cap. apparatus.