JP2003230819A - Hollow fiber membrane module and hollow fiber membrane module unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow fiber membrane module hard to generate the breakage of hollow fiber membranes even if the shaking of the hollow fiber membranes is generated at the time of filtering. <P>SOLUTION: Both end parts of a plurality of hollow fiber membranes are fixed to two mutually opposed housings so that the interval between mutual fixing members is shorter than the length of the hollow fiber membranes and members each having a curved surface with a radius of curvature of 5 mm or more are provided in the vicinity of the fixing members to constitute the hollow fiber membrane module. This hollow fiber membrane module can be well washed because the hollow fiber membranes are properly shaken and receives no damage caused by the bending of the hollow fiber membranes. Further, by setting the intervals between the members having the curved surfaces and the hollow fiber membranes and the distance or angle up to the root parts of the hollow fiber membranes to proper ranges, the bending of the hollow fiber membranes is effectively prevented. Thus, impurities such as fiber refuse or the like are prevented from entangling with the hollow fiber membranes to grow. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow fiber membrane module which can be suitably used for liquid filtration and the like.

[0002]

Hollow fiber membrane modules have been used in a wide range of fields such as the production of sterile water, drinking water, high-purity water, etc., or the purification of air. In recent years, in addition to these microfiltration applications, sewage While being applied to highly polluted water treatment applications such as secondary and tertiary treatments at treatment plants, solid-liquid separation in septic tanks, solid-liquid separation of SS components (suspended substances) in industrial wastewater, etc. is there.

Hollow fiber membrane modules suitable for use in highly polluted water filtration are disclosed in JP-A-4-334529, JP-A-5-23550, and JP-A-11-179162.
Japanese Patent Laid-Open No. 2000-229225, etc., accommodates an end portion of a sheet-shaped hollow fiber membrane bundle inside a housing,
A hollow fiber membrane module fixed by using a fixing resin is disclosed. When filtration is performed while washing the membrane surface of these hollow fiber membrane modules by applying a flow of liquid to be treated or air bubbles, filtration can be performed for a long period of time while preventing clogging of the membrane surface.

In these hollow fiber membrane modules, breakage easily occurs at the edge of the hollow fiber membrane, which is the boundary between the hollow fiber membrane fixing resin and the hollow fiber membrane. These breaks often occur due to bending of the hollow fiber membrane due to rocking and relaxation of the hollow fiber membrane during filtration of highly polluted water. As means for preventing breakage and breakage of the hollow fiber membrane, for example, JP-A-4-33452.
No. 9, JP-A-5-23550 discloses a method of embedding a hollow fiber membrane in a protective elastic resin layer, and further disposing a protective net material for suppressing the spread on the outer peripheral portion of the hollow fiber membrane. There is.

Further, in Japanese Patent Laid-Open No. 11-179162, the ends of the hollow fiber membrane bundle are fixed with an adhesive, and the periphery of the end portion of the hollow fiber membrane bundle is surrounded by an elastic body and a heat shrinkable tube. A method is described in which the elastic body is brought into contact with the outer peripheral portion of the hollow fiber membrane bundle by heating and shrinking, and the hollow fiber membrane is pressed and supported so that the hollow fiber membrane is not crushed.

Japanese Patent Laid-Open No. 2000-229225 discloses that
An elastic stress relaxation member is provided at a position of at least the edge of the portion fixed by the potting agent on the surface of the hollow fiber membrane bundle fixed by the potting agent.

[0007]

However, in the methods described in JP-A-4-334529 and JP-A-5-23550, when the protective net material is soft, breakage of the hollow fiber membrane is caused by the protective elastic resin layer. When the protective net material is hard, the hollow fiber membrane may come into contact with the tip of the protective net material to cause cracking due to friction. Moreover, if the expansion of the hollow fiber membranes is simply suppressed in order to prevent the occurrence of bending, an appropriate gap cannot be maintained between the hollow fiber membranes due to tightening, the cleaning effect is reduced, and fibrous contaminants in non-filtered water In some cases, the solid matter and the solid matter were entangled with the hollow fiber membrane, which made cleaning difficult.

Japanese Unexamined Patent Publication No. 11-179162 and Japanese Unexamined Patent Publication No. 2
The method described in Japanese Patent Application Publication No. 000-229225 discloses a method in which the hollow fiber membrane surrounded by an elastic body is further swayed by aeration treatment or the like, whereby collapse of the hollow fiber membrane occurs, and particularly When filtering a fluid such as sludge, which causes the hollow fiber membrane to undergo a large flow resistance, the hollow fiber membrane may be broken at the interface of the elastic body.

As a result of studies to solve the above problems, the present inventors have found a hollow fiber membrane module in which breakage of the hollow fiber membrane is unlikely to occur even under various conditions of use, and completed the present invention.

[0010]

That is, the gist of the present invention is that both ends of a plurality of hollow fiber membranes are provided in two opposing housings, and the spacing between the fixing members is shorter than the length of the hollow fiber membranes. It is fixed and has a radius of curvature of 5 near the fixing member.
A hollow fiber membrane module provided with a member having a curved surface of mm or more.

The distance between the member having the curved surface and the hollow fiber membrane closest to the member having the curved surface is 3 to 50.
mm, while effectively preventing breakage of the hollow fiber membrane,
It is preferable since it is possible to prevent the entanglement of foreign matters with the hollow fiber membrane. Further, among the parts of the member having the curved surface that can come into contact with the hollow fiber membrane, the distance between the farthest part from the hollow fiber membrane and the root part of the hollow fiber membrane closest to the farthest part is 100.
When it is not more than mm, the bending of the hollow fiber membrane is easily suppressed, and the effect of preventing breakage is further enhanced, which is more preferable.
Further, when the angle formed by the straight line connecting the furthest portion and the root portion of the closest hollow fiber membrane and the plane perpendicular to the fiber axis of the closest hollow fiber membrane is 60 degrees or more, the hollow fiber is It is more preferable because the membrane does not bend excessively.

Further, it is preferable that the member having the curved surface is an elastic body because the stress when contacting the hollow fiber membrane can be further alleviated. Further, when the hollow fiber membrane is in the form of a sheet,
The effect of preventing breakage of the hollow fiber membrane according to the present invention is remarkably exhibited. Further, it is preferable that the member having the curved surface is integrated with the housing, because the installation is easy.
Further, it is preferable that the member having the curved surface is arranged so as to completely surround the root portion of the hollow fiber membrane, since it becomes difficult for foreign matters to be entangled with the root portion of the hollow fiber membrane. Further, when the hollow fiber membrane is made of any material of polyvinylidene fluoride, polysulfone and polyacrylonitrile, the effect of preventing breakage of the hollow fiber membrane according to the present invention is particularly remarkable.

A second aspect of the present invention is a hollow fiber membrane module unit in which a plurality of hollow fiber membrane modules are arranged side by side in the horizontal direction and / or the vertical direction. Here, when the longitudinal direction of the hollow fiber membrane is arranged in the vertical direction,
The effect of preventing breakage of the hollow fiber membrane according to the present invention becomes remarkable. Further, when the member having the curved surface is provided only in the vicinity of the fixing member of the upper housing of the facing housings, it is possible to reliably prevent breakage of the hollow fiber membrane with fewer constituent members. You can

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
FIG. 1 is a schematic diagram showing an example of the hollow fiber membrane module of the present invention. In the hollow fiber membrane module 1 of the present invention, both ends of a plurality of hollow fiber membranes 3 are provided in two opposing housings 2,
The fixing members 4 are fixed to each other at an interval shorter than the length of the hollow fiber membranes 3, and the hollow fiber membranes 3 are arranged so as to have some relaxation, so that the cleaning property is good.
The relaxation interval is preferably 5% or less of the distance between the fixing members 4, and more preferably 3% or less.
At least one end of the housing 2 is provided with a pipe (not shown) that communicates with an internal passage for passing a processing liquid contained in the housing 2 and opens to the outside.

Here, in the vicinity of the fixing member 4, the radius of curvature 5
By providing the member 6 having a curved surface of not less than mm, even if the hollow fiber membrane oscillates, a curved line is drawn along the curved surface, so that the hollow fiber membrane is prevented from excessive bending and the hollow fiber membrane is It can be prevented from being damaged.

The member 6 having a curved surface is a member having a curved surface that is convex toward the hollow fiber membrane on the entire outer peripheral surface or at a portion that can come into contact with the hollow fiber membrane. Examples of the shape include a pipe-shaped material, a joined body of the pipe-shaped material and a plate-shaped material, and a shape in which a part of the plate-shaped material is curved.
2 to 5 are sectional views showing examples of the member 6 having a curved surface used in the present invention.

The radius of curvature means the radius of an arc formed by the cross-sectional outer circumference of the curved surface of the portion that can come into contact with the hollow fiber membrane.
If the arc is elliptical, it means the minor axis. When the radius of curvature is 5 mm or less, stress cannot be alleviated when the hollow fiber membrane comes into contact with a member having a curved surface, and it becomes difficult to prevent breakage.

Here, it is preferable that the distance between the member having a curved surface and the hollow fiber membrane located at the outermost peripheral portion of the plurality of hollow fiber membranes and closest to the member having a curved surface is 3 to 50 mm. If this distance is less than 3 mm, there is almost no gap between the hollow fiber membrane 3 and the member 6 having a curved surface.
It becomes easy for entanglement of fibrous impurities. On the other hand, 50 mm
If it exceeds, it becomes impossible to sufficiently alleviate the bending of the hollow fiber membrane. This distance is more preferably 5 to 30 mm.

The term "space" refers to a portion of the member having a curved surface that can come into contact with the hollow fiber membrane, which is the closest to the hollow fiber membrane, and the fixed portions at the roots of the hollow fiber membranes located at the outermost periphery. It refers to a distance between the hollow fiber and a plane that is substantially parallel to the longitudinal direction of the hollow fiber membrane, and corresponds to the distance A shown by the arrow in FIG. That is, it does not mean the distance that is variable by the swinging of the loosely arranged hollow fiber membranes.

Of the parts of the member having the curved surface that can come into contact with the hollow fiber membrane, the part farthest from the hollow fiber membrane,
The distance from the root part of the hollow fiber membrane closest to the farthest part corresponds to the distance B shown by the arrow in FIG. 7, but if it is too long, the effect of protecting the root part of the hollow fiber membrane becomes insufficient. Therefore, it is preferably 100 mm or less, and 75 mm
The following is more preferable. On the other hand, if it is too short or too long, the protective effect of the hollow fiber membrane root part becomes insufficient, so that it is preferably 10 mm or more, and more preferably 20 mm or more.

In addition, a straight line connecting a farthest portion of the member having a curved surface to the hollow fiber membrane and a root portion of the hollow fiber membrane closest to the hollow fiber membrane, and a fiber axis of the hollow fiber membrane. When the angle formed by a plane perpendicular to the direction, that is, the angle θ in FIG. 7 is 60 degrees or more, when the hollow fiber membrane contacts a member having a curved surface, the hollow fiber membrane is not largely deformed and the protective effect is enhanced. Therefore, it is preferably, and more preferably 70 degrees or more.

The plane perpendicular to the fiber axis direction of the hollow fiber membrane mentioned above means an average in a fixed portion where a plurality of hollow fiber membranes are arranged and fixed so as to face substantially the same direction. A surface perpendicular to the fiber axis direction. That is, in a fiber axis direction of a specific hollow fiber membrane that faces a slightly different direction, or in a midway portion of a hollow fiber membrane that is loosely arranged, a surface that is perpendicular to the variable fiber axis direction is not targeted. Absent.

As the material of the member having a curved surface, it is preferable to use an elastic body in order to alleviate the stress when contacting the hollow fiber membrane. At this time, the entire member may be made of an elastic body, or at least the surface of the portion that may come into contact with the hollow fiber membrane may be covered with the elastic body. As an example, a flexible resin such as rubber or silicone resin or urethane resin is used alone, or a resin support such as vinyl chloride or acrylonitrile butadiene styrene containing soft urethane or rubber is used on the surface of the resin support. And the like.

The hollow fiber membrane module of the present invention may have a cylindrical shape, but when the hollow fiber membrane is in the form of a sheet as in the example of FIG. 1, a member having a curved surface and a hollow fiber membrane are provided. The distance between and is not so different between the inside and outside of the bundle of hollow fiber membranes, and the stress relaxation effect can be exerted on more hollow fiber membranes, which is preferable. Although the member having a curved surface can obtain the effect of the present invention only by arranging it on one side of the sheet-shaped hollow fiber membrane, it is preferable to arrange it on both sides of the sheet-shaped hollow fiber membrane.

The member having a curved surface may be provided separately from the housing of the hollow fiber membrane module, but if it is arranged so as to be integrated with the housing, the positional relationship between the member having a curved surface and the hollow fiber membrane module is special. It is preferable because it can be arranged without adjusting The member having a curved surface may be embedded and fixed in the fixing member when fixed by the fixing member, or may be adhered to the fixing member or the housing after a series of operations for manufacturing the module is completed, You may fix it by tying it with a string or an insulock, or fix it with a screw.
It is also possible to mold it integrally with the housing.

Further, as shown in FIG. 8, when the member having the curved surface is arranged so as to completely surround the base of the hollow fiber membrane, the non-treatment liquid does not directly flow toward the base of the hollow fiber membrane. It is more preferable because contaminants such as fiber waste in the non-treatment liquid are less likely to get entangled. At this time, in order to prevent air from accumulating in the portion surrounded by the curved member, a small hole or mesh may be provided in the curved member.

The hollow fiber membrane used in the present invention may be a hollow fiber membrane that is simply drawn. However, in view of the processability of the hollow fiber membrane module, the preferred form is a hollow fiber membrane bundle with a saddle frame. Wound material wound in multiple strands on the body, knitted fabric using hollow fiber membranes as wefts, or several layers of this knitted fabric, or an appropriate length without cutting the knitted fabric It is possible to fold and stack the above to form a laminated body.
The number of layers of knitted fabric (folding) when making a laminate is
Although it varies depending on the thickness of the knitted fabric, that is, the thickness of the hollow fiber membrane and the number of yarns of the hollow fiber membrane when knitting the knitted fabric, it is usually preferably about 10 sheets. The length of the hollow fiber membrane is 20
The range of 0 mm to 2000 mm is preferable from the viewpoint of handleability, and the range of 350 mm to 1200 mm is more preferable.

The material of the hollow fiber membrane used in the present invention is not necessarily limited, and polysulfone-based resins, polyacrylonitrile, cellulose derivatives, polyolefins such as polyethylene and polypropylene, and fluorine-based resins such as polyvinylidene fluoride and polytetrafluoroethylene. Polyamide, polyester, polymethacrylate, polyacrylate, etc. can be used. Further, it may be a copolymer of these resins or one in which a substituent is introduced. Further, it may be a mixture of two or more kinds of resins.

Among these materials, polyvinylidene fluoride, polysulfone, and polyacrylonitrile have comparatively weak strengths, so that the effect of the member having a curved surface of the present invention is more remarkably exhibited.

As long as the hollow fiber membrane can be used as a filtration membrane, its pore diameter, porosity, film thickness, outer diameter, etc. are not particularly limited, but the outer diameter is 20 to 2000 μm, and the pore diameter is A range of 0.001 to 5 μm, a porosity of 20 to 90%, and a film thickness of 5 to 300 μm is preferably used.

The housing material used for the hollow fiber membrane module of the present invention may be any one having mechanical strength and durability, such as polycarbonate, polysulfone, polyolefin, PVC (polyvinyl chloride), acrylic resin, ABS. Resin, modified PPE (polyphenylene ether), etc. can be used. When incineration is required after use, it is preferable to use a hydrocarbon resin such as polyolefin that can be completely burned without producing toxic gas by burning.

The hollow fiber membrane module unit in which a plurality of the hollow fiber membrane modules of the present invention described above are arranged in the horizontal direction and / or the vertical direction can increase the filtration amount and
Excellent handleability. Further, when the arrangement direction of the hollow fiber membranes is arranged so that the fiber axis is oriented in the vertical direction, the flow direction from the bottom to the top when the flow of the liquid to be treated or the bubbles are applied to the hollow fiber membranes for cleaning. In the opposite direction, whereby the hollow fiber membrane swings mainly in the horizontal direction. Therefore, by arranging the members having the curved surface so as to sandwich the sheet-shaped hollow fiber membrane, the effect of stress relaxation can be exerted on more hollow fiber membranes, and thus the effect of the present invention is more remarkably exhibited. .

The present invention will be described below with reference to examples. <Example 1> Polyvinylidene fluoride hollow fiber membrane (outer diameter 12
2 μm curing type urethane resin C4403 / N4224 (manufactured by Nippon Polyurethane Co., Ltd.) was used as a fixing member and fixed to the housing to manufacture the flat hollow fiber membrane module shown in FIG. The distance between the fixing members of the membrane module was 350 mm, and the average effective length of the hollow fiber membrane was 360 mm.

A member having a curved surface has a diameter of about 2
A 0 mm PVC pipe is orthogonal to the fiber axis direction of the hollow fiber membrane so as to surround the entire outer circumference of the hollow fiber membrane module.
It was attached to the housing part via a bracket member.

At this time, the distance between the member having the curved surface and the closest hollow fiber membrane (hereinafter referred to as the distance A) is 1.
The distance between the most distant part of the hollow fiber membrane having a curved surface of 3 mm and the member having the curved surface and the root part of the hollow fiber membrane closest to the hollow fiber membrane (hereinafter referred to as distance B) is 5
0 mm, a straight line connecting a portion farthest from the hollow fiber membrane among the portions where the member having the curved surface can come into contact with the hollow fiber membrane, and a root portion of the hollow fiber membrane located at the outermost peripheral portion of the hollow fiber membrane, The angle formed by the plane perpendicular to the fiber axis direction of the hollow fiber membrane (hereinafter, referred to as angle θ) was 75 degrees.

This hollow fiber membrane module was tested for solid concentration S
While arranging in activated sludge with S of 10000 mg / L, while performing air diffusion with an intensity of 100 m ³ / m ² · hr from the air diffuser arranged below the hollow fiber membrane module, 1
Weekly filtration was performed.

After that, the hollow fiber membrane module was pulled up from the sludge, and the hollow fiber membrane was visually inspected. As a result, a small amount of foreign matter was attached to the end of the hollow fiber membrane, but it was easily removed by washing with water. I was able to. Further, there were three bent portions, but no cracks or breaks were observed. After the hose was attached to the housing so that air could be ventilated inside the hollow fiber membrane of this hollow fiber membrane module, it was immersed in water and the air pressure was adjusted to 0.05 MPa. No leak was observed.

Example 2 A hollow fiber membrane module was prepared in the same manner as in Example 1 except that the material of the hollow fiber membrane was polysulfone, the distance A was 21 mm, and the angle θ was 65 degrees. I went. After that, when the hollow fiber membrane module was pulled up and the bent state was visually observed, a small amount of impurities adhered to the end of the hollow fiber membrane, but could be easily removed by washing with water. Further, there were three bent portions, but no cracks or breaks were observed.
Furthermore, as a result of performing a leak test by pressurizing air in the same manner as in Example 1, no air leak was observed.

<Embodiment 3> All were carried out except that the distance between the fixing members of the membrane module was 500 mm, the average effective length of the hollow fiber membrane was 530 mm, the distance A was 51 mm, the distance B was 150 mm, and the angle θ was 70 degrees. The same hollow fiber membrane module as in Example 1 was prepared and the same filtration test was performed. afterwards,
When the hollow fiber membrane module was pulled up and the bent state was visually observed, a small amount of impurities adhered to the end of the hollow fiber membrane, but could be easily removed by washing with water. Further, there were 12 bent portions, but no cracks or fractures were observed. Furthermore, as a result of performing a leak test by pressurizing air in the same manner as in Example 1, no air leak was observed.

Example 4 The distance between the fixing members of the membrane module was 1150 mm, and the average effective length of the hollow fiber membrane was 1170 m.
m as a member having a curved surface, the structure shown in FIG.
A member having a width of 5 mm, a height of 20 mm, and a tip having a radius of curvature of 5 mm on the side facing the hollow fiber membrane is arranged so as to surround the entire outer circumference of the hollow fiber membrane so as to be integrated with the housing. A hollow fiber membrane module was prepared in the same manner as in Example 1, and the same filtration test was performed. In addition, the interval A at this time
Was 4 mm, the distance B was 22 mm, and the angle θ was 66 degrees.

Then, the hollow fiber membrane module is pulled up,
When the bent state was visually observed, a small amount of impurities adhered to the end of the hollow fiber membrane, but could be easily removed by washing with water. In addition, there was no bent portion, and no crack or break was observed. Furthermore, Example 1
As a result of conducting a leak test by applying the same air pressure as above, no air leak was observed.

<Comparative Example 1> A hollow fiber membrane module similar to that of Example 1 was prepared except that a member having a curved surface was not provided.
The same filtration test was performed. After that, when the hollow fiber membrane module was pulled up and the bent state was visually observed,
A small amount of contaminants adhered to the end of the hollow fiber membrane, but could be easily removed by washing with water. On the other hand, there were 80 bent portions, 7 cracked portions, and 8 broken portions.

Comparative Example 2 A hollow fiber membrane module was prepared in the same manner as in Example 1 except that a member having a curved surface was placed in contact with the hollow fiber membrane, and the same filtration test was conducted. Then, when the hollow fiber membrane module was pulled up and the bent state was visually observed, a large amount of contaminants adhered to the ends of the hollow fiber membrane and could not be removed by washing with water. No bent portion was present, and no cracks or fractures were observed. Furthermore, as a result of performing a leak test by pressurizing air in the same manner as in Example 1, no air leak was observed.

[0044]

According to the hollow fiber membrane module of the present invention,
Both ends of the plurality of hollow fiber membranes are fixed to two housings facing each other such that the distance between the fixing members is shorter than the length of the hollow fiber membrane, and a curved surface having a radius of curvature of 5 mm or more is provided in the vicinity of the fixing members. Since the member is provided, the hollow fiber membrane can be appropriately swung for good cleaning, and the hollow fiber membrane is not damaged by being bent. Further, by setting the distance between the member having a curved surface and the hollow fiber membrane, the distance to the root of the hollow fiber membrane and the angle to an appropriate range, the bending of the hollow fiber membrane can be effectively prevented, and the hollow fiber membrane can be effectively prevented. It is possible to prevent foreign matters such as fiber debris from being entangled with the film and growing. Further, by integrally forming the member having the curved surface and the housing, the member can be easily installed. Further, when the member having the curved surface completely surrounds the root portion of the hollow fiber membrane, the effect of preventing the entanglement of impurities can be made more remarkable.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a hollow fiber membrane module of the present invention.

FIG. 2 is a sectional view showing an example of a member having a curved surface of the present invention.

FIG. 3 is a cross-sectional view showing another example of a member having a curved surface of the present invention.

FIG. 4 is a cross-sectional view showing another example of a member having a curved surface of the present invention.

FIG. 5 is a cross-sectional view showing another example of a member having a curved surface of the present invention.

FIG. 6 is a cross-sectional view showing an example of an installation position of a member having a curved surface according to the present invention.

FIG. 7 is a cross-sectional view showing an example of an installation position of a member having a curved surface according to the present invention.

FIG. 8 is a cross-sectional view showing an example of the form of a member having a curved surface according to the present invention.

[Explanation of symbols]

1 Hollow fiber membrane module 2 housing 3 hollow fiber membranes 4 fixing members 6 Members with curved surfaces 7 Hollow fiber membrane located at the outermost periphery

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/44 ZAB C02F 1/44 ZABK (72) Inventor Noritaka Shibata 4-chome, Sunadabashi, Higashi-ku, Aichi Prefecture No. 60 Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Yasuo Oda 4-1-1 Sunadabashi, Higashi-ku, Nagoya, Aichi Prefecture F-Term (Reference) 4D006 GA07 HA02 HA07 HA19 JA02A JA02B JA12A JA12B JA13A JA25A JA30A KA44 LA06 MA01 MA31 MB02 MB16 MC29 MC29X MC39 MC62 MC62X PA01 PB02 PB08 PB15 PB17 PB22 PC51 PC62 PC63 PC64

Claims (12)

[Claims] 1. Both ends of a plurality of hollow fiber membranes are fixed to two opposing housings with a spacing between the fixing members being shorter than the length of the hollow fiber membranes, and in the vicinity of the fixing members.
A hollow fiber membrane module provided with a member having a curved surface with a radius of curvature of 5 mm or more. 2. The distance between the member having the curved surface and the hollow fiber membrane closest to the member having the curved surface is 3 to 50 mm.
The hollow fiber membrane module according to claim 1, which is 3. The distance between the farthest part of the member having the curved surface that can come into contact with the hollow fiber membrane and the root part of the hollow fiber membrane closest to the farthest part is:
The hollow fiber membrane module according to claim 2, which has a length of 100 mm or less. 4. The angle formed by a straight line connecting the farthest portion and the root portion of the closest hollow fiber membrane and a plane perpendicular to the fiber axis of the closest hollow fiber membrane is 60 degrees or more. The hollow fiber membrane module according to claim 3. 5. The hollow fiber membrane module according to claim 1, wherein the member having the curved surface is made of an elastic body. 6. The hollow fiber membrane is sheet-shaped.
The hollow fiber membrane module according to claim 5. 7. The hollow fiber membrane module according to claim 1, wherein the member having the curved surface is integrated with the housing. 8. The member having the curved surface is arranged so as to completely surround the root portion of the hollow fiber membrane.
7. The hollow fiber membrane module according to claim 7. 9. The hollow fiber membrane is polyvinylidene fluoride,
The hollow fiber membrane module according to any one of claims 1 to 8, which is made of a material selected from polysulfone and polyacrylonitrile. 10. A hollow fiber membrane module unit comprising a plurality of the hollow fiber membrane modules according to any one of claims 1 to 9 arranged side by side in a horizontal direction and / or a vertical direction. 11. The hollow fiber membrane module unit according to claim 10, wherein a longitudinal direction of the hollow fiber membrane is arranged in a vertical direction. 12. The hollow fiber membrane module unit according to claim 11, wherein the member having the curved surface is provided only in the vicinity of the fixing member of an upper housing of the facing housings.