JP2000051670A - Hollow fiber membrane module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the uniform and efficient cleaning operation and make the attaching/detaching work of individual parts easy by providing a compact element structure consisting of an air pipe, a water conduit, an air bleeding means and the like which are effectively arranged on two fixing members. SOLUTION: An assembly comprising filtration screens 1, fixing members 2a, 2b, an air bleeding means 9, an element cap 11, a water conduit 12, an air pipe 13 and the like is introduced from above a can body 3, the top of the assembly being fixedly covered with a cap 4. Further in a cleaning operation, a treating water supply is suspended and a water to be treated is poured into a chamber 16 for the water to be treated. In this state, a scrubbing air supplied from an air supply aperture 8 is injected to the base part of each of the filtration screens 1 by the air bleeding means 9, passing through a gas passage 17 and the air pipe 13. The scrubbing air thus injected forms air bubbles and ascends while cleaning the surface of a hollow fiber membrane knitted fabric which constitutes the filtration screens 1, between the screens 1, and is discharged outside a system from an air outlet 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention can be suitably used for filtration of highly polluting liquids such as filtration of river water and lake water, filtration of industrial water, and waste water treatment, as well as high-order treatment after sand filtration. The present invention relates to a hollow fiber membrane module.

[0002]

2. Description of the Related Art Hollow fiber membrane modules are used in the field of microfiltration such as the production of sterile water, high-purity water and drinking water, and the purification of air, as well as secondary and tertiary treatment in sewage treatment plants, and septic tanks. It has also been applied to the field of highly polluting water treatment such as solid-liquid separation.

[0003] In high-pollutant water treatment, clogging during filtration is often large. In such a case, after performing the filtration treatment for a certain period of time, air is sent from the bottom of the module to vibrate the hollow fiber membrane, and the membrane is vibrated. A membrane cleaning such as a scrubbing operation for cleaning the surface and a reverse cleaning for passing water in a direction opposite to the filtration direction is repeatedly performed.

However, when a hollow fiber membrane module used for conventional microfiltration, in which hollow fiber membrane knitted fabrics are converged and arranged in a concentric manner, is used for highly polluting water treatment, the processing time elapses. As a result, the hollow fiber membranes adhere to each other due to deposits such as organic substances attached to the membrane surface, the effective area of the hollow fiber membrane in the module decreases, the filtration flow rate sharply decreases, and the membrane is periodically cleaned. In some cases, the membrane function is not easily recovered even after the filtration, and the filtration efficiency may be significantly reduced.

[0005] As a solution to the problems such as a decrease in the effective area and a decrease in the cleaning efficiency, a hollow fiber membrane knitted fabric is spread in the form of a filter screen, and one end or both ends of the hollow fiber membrane are kept open. A flat hollow fiber membrane module having a rectangular cross section fixed to a frame has been proposed. By arranging a plurality of the hollow fiber membrane modules at appropriate intervals, the membrane surface can be easily cleaned and a decrease in filtration efficiency is suppressed. It became possible.

[0006] In this flat type hollow fiber membrane module, a filtration operation is often performed by suctioning the secondary side of the filtration membrane. In order to obtain higher filtration performance, the hollow fiber membrane module must be pressure-resistant such as a cylindrical container. It is stored in a container, and the primary side of the filtration membrane is further pressurized to perform filtration.

However, when a flat hollow fiber membrane module is housed in a cylindrical container, the proportion occupied by portions other than the hollow fiber membrane increases, resulting in poor volumetric efficiency. When housed in a rectangular container, a pressure-resistant structure is obtained. For this reason, the cost of the container becomes expensive, for example, a reinforcing member is required.

[0008]

As a structure for solving the above-mentioned problem relating to volumetric efficiency, a plurality of flat hollow fiber membrane knitted fabrics are arranged in parallel or folded in a zigzag shape to form a hollow fiber membrane. Japanese Patent Application Laid-Open No. 9-141063 proposes a hollow fiber membrane module which is capable of maintaining a high filtration function for a long period of time by performing scrubbing with air supplied from an air header.

However, in the hollow fiber membrane module, the supplied air does not flow evenly between the hollow fiber membrane knitted fabrics, causing a drift or a plurality of air bubbles coming together during the ascending to form large bubbles. Or rise.
Due to this phenomenon, the entire surface of the hollow fiber membrane is not washed, so that a more uniform recovery of the filtration function cannot be sufficiently achieved,
It was necessary to supply more air than necessary.

In order to solve such a problem, a diffusing nozzle is provided between the respective laminates near the upper surface of the lower fixing member of the hollow fiber membrane knitted fabric arranged in parallel in the vertical direction, and the hollow fiber membrane knitting is provided. Japanese Patent Application No. Hei 9-15841 discloses a hollow fiber membrane module in which air is reliably supplied between fabrics to improve the washing property.
No. 6 filed. By employing the structure in which the air diffusion nozzle is provided, it has become possible to maintain a high filtration function for a long period of time. However, when attaching each component to the can body, it is necessary to perform an operation of connecting the air pipe to the air diffuser nozzle, and the can body needs an opening for the connection work and a treated water outlet pipe at the lower part. For this reason, there has been a problem to be improved in the case of further reducing the filtration cost, such as a complicated can body structure.

An object of the present invention is to provide a hollow fiber membrane module having a structure in which a filtration screen made of a hollow fiber membrane knitted fabric is provided in a can body container, wherein air for scrubbing is passed between the filtration screens made of the hollow fiber membrane knitted fabric. Provide a hollow fiber membrane module that can perform more uniform and efficient cleaning by providing reliable supply, has a simple structure, can easily attach and detach components, and has good handling and maintenance work efficiency. Is to do.

[0012]

According to the present invention, there is provided a hollow fiber membrane module comprising a filtration screen made of a hollow fiber membrane knitted fabric, and an upper end of the filtration screen being an upper end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric. An upper fixing member for fixing while maintaining the open state of the filter screen; a lower fixing member for fixing the lower end of the filtration screen while maintaining the open state of the lower end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric; A water pipe penetrating the member and the lower fixing member, communicating a side where the upper end of each hollow fiber membrane of the upper fixing member opens and a side where the lower end of each hollow fiber membrane of the lower fixing member opens; A gas passage communicating with an air discharging means provided near a surface of the fixing member on the upper fixing member side and an air supply port provided on an edge side surface of the upper fixing member, and having an opening on the lower fixing member side; And the lower step of the gas passage A vent pipe for connecting the material-side opening to the air releasing means, for ventilating the air from the air supply port to the air releasing means, and a surface on the side where the lower end of each hollow fiber membrane of the lower fixing member opens. A partition element for partitioning the region and forming a lower treated water chamber, and inserting and arranging the filter element in the can body container. And an upper treated water chamber that communicates with the treated water outlet and communicates with the lower treated water chamber and the water pipe; separated from the upper treated water chamber and the lower treated water chamber. A water chamber to be treated which is formed as a closed region, a side surface of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric is located, and is connected to a water supply port and an air outlet to be treated. The supply port is opened toward the outside of the can body. Characterized in that a part fixing member.

According to the present invention, the air for scrubbing can be uniformly and reliably supplied to the filtration screen of the hollow fiber membrane knitted fabric, the structure is simplified, and each part is efficiently used. With good arrangement, good operability and workability can be obtained.

The air release means in the hollow fiber membrane module of the present invention has a structure in which a disc-shaped member having an air discharge hole is provided with a slit portion penetrating from the front surface to the back surface, and a hollow fiber membrane knitted fabric is provided in the slit. By incorporating the filter screen in the vicinity of the upper surface of the lower fixing member in a state where the filter screen is inserted, a more effective ventilation effect can be obtained.

[0015]

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 hollow fiber membrane module of the present invention. This hollow fiber membrane module has a configuration in which a plurality of filtration screens 1 made of a hollow fiber membrane knitted fabric are arranged in parallel at a predetermined interval in a can body container mainly composed of a can body 3 and a cap 4. Have. The upper end and the lower end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric are fixed to the upper fixing member 2b and the lower fixing member 2a, respectively, while maintaining the open state. These fixing members separate the treated water chambers 14 and 15 including the surfaces on the side where the open ends of the hollow fiber membranes are opened, and the treated water chamber 16 formed of the space where the side surface of each hollow fiber membrane is located. Functions as part of a partition. The lower treated water chamber 15 is provided with a lower fixing member 2a.
The hollow fiber membrane is defined by an opening and a lower end of each hollow fiber membrane.

Between the two fixing members, there is provided a water pipe 12 which penetrates these fixing members and communicates between treated water chambers 14 and 15 arranged above and below. The treated water in the water chamber 15 is supplied to the upper treated water chamber 14.
And finally taken out of the module from the treated water outlet 6.

The upper fixing member 2b includes a can 3 and a cap 4
And an air supply port 8 is opened on the side surface of the edge. The air supply port 8 communicates with a gas passage 17 having an opening on the lower fixing member side, and
The air release means 9 can be ventilated through a ventilation pipe (air pipe) 13 connecting the air release means 7 and the air release means 9 provided near the upper surface of the lower fixing member 2a. The air discharging means 9 has a slit-shaped through hole having an air discharge hole, and each filtration screen 1 is inserted into this through hole.

In the hollow fiber membrane module having the structure shown in FIG. 1, an assembly (element) including the filtration screen 1, the fixing members 2a and 2b, the air discharging means 9, the element cap 11, the water pipe 12, the air pipe 13, and the like is provided. Is inserted into the can body 3 from above and fixed so that the upper part is closed by the cap 4. In this way, by supplying the elements in a completed state before being housed in the can body container so that they can be assembled, the assembled element is arranged in the can body 3 and fixed with the cap 4. Assembly of the hollow fiber membrane module can be completed with a simple operation, and operations such as regular replacement of elements can be performed with good workability. Such good handling and workability can be achieved by a compact element structure in which the air pipe 13, the water pipe 12, the air discharging means 9 and the like are efficiently arranged with respect to the two fixing members.

On the other hand, the can 3 is provided with a treated water supply port 5, a deposit outlet 7, and an air outlet 10, and the cap 4 is provided with a treated water outlet 6.

FIG. 2 is a schematic plan view showing the structure of an example of the air discharging means, and FIG. 3 is a sectional view thereof. In addition,
For the sake of explanation, the positional relationship between the slits and the air discharge holes in FIG. 3 is different from that in FIG.

2 and 3, the air discharging means 9 has a disk-like shape having an outer diameter corresponding to the lower fixing member 2a, and has an inner space (hollow portion; shown by a broken line in FIG. 2) provided therein. 20) has a function as an air distributor. The root portion of the filtration screen 1 is inserted into each slit 21, and an air discharge hole 19 provided in the slit 21 is opened toward the root portion.

The treatment of the water to be treated in the hollow fiber membrane module having the structure shown in FIGS. 1 to 3 can be performed, for example, as follows. First, the air outlet 10 and the sediment outlet 7 are closed by appropriate means, and the water to be treated is 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 side surface of the hollow fiber membrane in the hollow fiber membrane knitted fabric constituting the filtration screen 1, and the solid matter is filtered by passing into the hollow fiber membrane. You. The treated water subjected to the filtration treatment flows from the hollow portion of the hollow fiber membrane to the treated water chambers 14, 1 and
5 and the treated water in the treated water chamber 15
Through the treated water chamber 14 and finally taken out of the module from the treated water outlet 6. If necessary, suction from the treated water outlet 6 side and pressurization from the treated water supply port 5 side can be used together.

The operation of washing the filtration screen 1 can be performed, for example, as follows. When the filtration treatment for a predetermined time is performed, the supply of the treated water is stopped, and the treated water chamber 16 is filled with the treated water.
After releasing 0, scrubbing air is supplied from the air supply port 8. The supplied air passes through the gas passage 15 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 solids separated from the surface of each hollow fiber membrane by this scrubbing operation settle at the lower part of the can body 3 to form deposits. This deposit can be discharged from the deposit outlet 7 to the outside of the system.

The hollow fiber membrane constituting the hollow fiber membrane knitted fabric used in the present invention is composed of various materials such as polyolefin, cellulose, polyvinyl alcohol, polysulfone, polymethyl methacrylate and composites thereof. Can be used, knitting and weaving properties to knitting and weaving,
An olefin-based hollow fiber membrane such as polyethylene having high strength and elongation is preferably used in view of coping with the shaking caused by the 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.

The hollow fiber membrane knitted fabric is based on any knitting method and weaving method as long as the hollow fiber membrane is arranged on one of the warp and the weft and the function as a filtration membrane is maintained. You may.

The hollow fiber membrane knitted fabric is developed into a screen to form a filtration screen 1, and a plurality of the screens are arranged in parallel. The pitch between each filtration screen is preferably 3 to 50 mm, more preferably 5 to 20 mm. At a pitch of 3 mm or less, when the sediment after scrubbing is discharged, the probability that solids separated from the side surface of the hollow fiber membrane are caught between the filtration screens and remain there may be high. In some cases, the membrane area that can be accommodated in the hollow fiber membrane module cannot be sufficiently obtained.

The upper fixing members 2a and 2b function to fix the hollow fiber membrane knitted fabric and to function as a member for separating the water to be treated and the treated water without leaking, and include, for example, urethane resin, epoxy resin and unsaturated polyester resin. And the like. The fixing of the hollow fiber membrane to these fixing members can be performed by a conventional method.

As described above, the upper fixing member 2b is
The outer peripheral portion (edge) has a function of fixing the element by being sandwiched between the can body 3 and the cap 4. In addition,
These can be fixed using various types of fixing means such as a combination of bolts and nuts, for example, using a flange structure as shown in the figure.

Further, as described above, the upper fixing member 2b
Has an air supply port 8 for supplying air for scrubbing on its outer peripheral side wall, and a gas passage 15 communicating with the air supply port 8.
The connection port with the air pipe 13 is provided toward the water chamber to be treated on the side surface of the hollow fiber membrane. This scrubbing air supply structure eliminates the need to connect the air piping from outside the can to the air discharge means when mounting the element inside the can, which was done with the conventional structure, greatly simplifying the mounting work of the element At the same time, the connection opening for the can body can be omitted.

An element cap 11 is fixed to the lower fixing member 2a without leakage from the outside, and a treated water chamber 15 is formed by these members. The portion collected in the treated water chamber 15 by the treated water filtered by the hollow fiber membrane is guided to the upper treated water chamber 14 by the water guide pipe 12.

The thickness of each fixing member can be selected according to the strength of the material constituting the fixing member, the combined use of reinforcing members, and the like. 0.2-0.6R is more preferred. If it is less than 0.1R, it may be difficult to secure pressure resistance, and if it exceeds 1R, an unnecessarily large amount of constituent materials such as resin may be required.

The element cap 11 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 adhered to the fixing member 2a or an O-ring. And is fixed without liquid leakage using a known member.

The water guide tube 12 is made of resin, taking into consideration pressure resistance, water resistance, corrosion resistance, elution resistance, adhesion to a fixing member, and the like.
It can be made of a material such as a metal, and the hole diameter and the number of the holes can be appropriately selected according to the amount of the liquid to be treated.

The air discharging 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, near the upper surface of the lower fixing portion 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 shape and size of the slits provided in the air discharging means 9 are determined by the shape and arrangement pitch of the filtration screen 1,
Furthermore, it can be set in consideration of the cleaning effect.
Further, the position of the air discharge hole is not particularly limited as long as it is a position where a good cleaning process by scrubbing can be performed.
In consideration of the uniformity of air supply to the filtration screen 1 and the treatment of solids deposited in the slit, it is preferable to provide the filter screen 1 on the inner wall of the slit as shown in FIGS. FIG.
The arrangement pitch of the air discharge holes 19 when provided on the inner wall of the slit as in 3 is preferably 10 mm to 70 mm in consideration of the uniformity of bubble formation. If it is smaller than 10 mm, the supply of air bubbles may be excessive,
If it is larger, unevenness in washing of the hollow fiber knitted fabric due to bubbles may occur. Regarding the air discharge holes 19, the number of holes, the hole diameter, the pitch, and the like can be set according to the turbidity of the water to be treated, turbidity characteristics, cleaning conditions, and the like.
For example, the hole diameter is 0.5 to 5 mm, more preferably 1 to 3 m
m. If it is less than 0.5 mm, clogging may easily occur, and if it exceeds 5 mm, it may be difficult to balance the discharge amount between the holes, and excessive scrubbing air may be required.

It is preferable that the container mainly composed of the can 3 and the cap 4 has a cylindrical portion in order to ensure pressure resistance, and in consideration of pressure resistance, water resistance, corrosion resistance, elution resistance and the like. From a material such as resin or metal. Further, the can body 3 may have a structure that can be separated at an appropriate portion.

[0037]

According to the hollow fiber membrane module of the present invention, the air for scrubbing is reliably and uniformly supplied between the filtration screens made of the hollow fiber membrane knitted fabric, so that uniform and efficient washing can be performed, and the hollow fiber membrane module can be used for a long time. The filtration efficiency can be maintained, the element having the filtration screen and the like can be easily attached to and detached from the can container, and the structure of the can container itself can be simplified.

[Brief description of the drawings]

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

FIG. 2 is a schematic plan view of an example of an air discharging means that can be used in the present invention.

FIG. 3 is a schematic cross-sectional view of an example of an air discharging means that can be used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filtration screen 2a Lower fixing member 2b Upper fixing member 3 Can 4 Cap 5 Treatment water supply port 6 Treated water outlet 7 Sediment outlet 8 Air supply port 9 Air discharge means 10 Air outlet 11 Element cap 12 Water pipe 13 Air pipe 14 Upper treated water chamber 15 Lower treated water chamber 16 Treated water chamber 17 Gas passage 18 Air pipe connection 19 Air discharge hole 20 Cavity 21 Slit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D006 GA07 HA02 HA06 HA09 HA12 HA16 HA19 JA07A JA07C JA13Z JA18A JA19A JA19C JA20Z JA29A JA29C JA31A JB03 KA43 KC02 KC14 MA01 MB16 MC16 MC22 MC33 MC37 MC62 PA01 PB02 PB61 PCB08

Claims (4)

[Claims] 1. A filter screen made of a hollow fiber membrane knitted fabric, an upper fixing member for fixing an upper end of the filter screen while maintaining an open state of an upper end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric, A lower fixing member for fixing the lower end of the filtration screen while maintaining an open state of the lower end of each hollow fiber membrane constituting the hollow fiber membrane knitted fabric; and an upper fixing member that penetrates the upper fixing member and the lower fixing member. A water conduit connecting the side of the lower fixing member where the upper end of each hollow fiber membrane opens to the side of the lower fixing member where the lower end of the hollow fiber membrane opens, and provided near the upper fixing member side surface of the lower fixing member A gas passage communicating with an air supply port provided on an edge side surface of the upper fixing member and having an opening on the lower fixing member side; and an opening of the gas passage on the lower process member side. And the air discharging means, A partition for forming a lower treated water chamber by partitioning a region including a vent pipe for venting from the air supply port to the air discharging means and a surface of the lower fixing member on the side where the lower end of each hollow fiber membrane is opened. And a filter element having a member on the side where each hollow fiber membrane of the upper fixing member is open, and is communicated with the treated water outlet. And an upper treated water chamber communicating with the lower treated water chamber by the water guide pipe; formed as a region separated from the upper treated water chamber and the lower treated water chamber to constitute the hollow fiber membrane knitted fabric. And a treated water chamber communicating with a treated water supply port and an air outlet; and the air supply port is opened toward the outside of the can body container. Characterized in that the upper fixing member is arranged in the hollow Thread membrane filtration module. 2. The air discharge means has a structure in which a disc-shaped member having an air discharge hole is provided with a slit penetrating through the disc-shaped member perpendicularly to a radial direction of the disc-shaped member. The hollow fiber membrane module according to claim 1, wherein the filtration screen is arranged so as to pass through a slit. 3. A side surface of an edge of the upper fixing member forms a part of an outer wall surface of the can body container, and the air supply port is arranged on the side surface of the edge. 3. The hollow fiber membrane module according to item 1. 4. The hollow fiber membrane module according to claim 1, wherein a plurality of said filtration screens are arranged in parallel at a predetermined interval.