WO2019146229A1

WO2019146229A1 - Filtration module

Info

Publication number: WO2019146229A1
Application number: PCT/JP2018/043038
Authority: WO
Inventors: 池田　啓一; 森田　徹
Original assignee: 住友電気工業株式会社
Priority date: 2018-01-24
Filing date: 2018-11-21
Publication date: 2019-08-01
Also published as: CN111587145A; JP7003685B2; JP2019126769A; CN111587145B

Abstract

A filtration module according to one aspect of the present disclosure is provided with: a plurality of hollow fiber membranes that are pulled into alignment in one direction; a cylindrical casing that stores the hollow fiber membranes and has, on a side surface thereof, a liquid concentrate nozzle for discharging a liquid concentrate; and an intake blocking member that is inserted into the concentrated liquid nozzle and that prevents the hollow fiber membranes from entering the liquid concentrate nozzle.

Description

Filtration module

The present disclosure relates to a filtration module. This application claims the priority based on Japanese Patent Application No. 2018-009547 filed on Jan. 24, 2018, and incorporates all the contents described in the Japanese application.

In order to filter various liquids to be treated, a plurality of hollow fiber membranes aligned in one direction are accommodated in a cylindrical casing, and the liquid to be treated is treated from a liquid nozzle provided at one end of the casing. The filtrate is supplied into the casing and discharged from the filtrate nozzle provided at the other end of the casing into the internal space of the hollow fiber membrane, and the concentrate nozzle provided on the side near the other end of the casing A so-called cross flow type filtration module is used which discharges the concentrate obtained by concentrating the liquid to be treated.

In such a filtration module, a flow straightening cylinder having a large number of flow straightening holes is disposed so as to surround a bundle of hollow fiber membranes inside a region where the concentrated liquid nozzle of the casing is disposed, and the hollow fiber membranes are concentrated liquid It is made not to be drawn into the nozzle (see WO 2008/035593).

International Publication 2008/035559

A filtration module according to an aspect of the present disclosure is a cylinder having a plurality of hollow fiber membranes aligned in one direction, a plurality of hollow fiber membranes, and a concentrate nozzle on a side surface for discharging a concentrate. And a pull-in blocking member inserted into the concentrate nozzle to prevent the hollow fiber membrane from entering the concentrate nozzle.

FIG. 1 is a schematic cross-sectional view showing a filtration module according to an embodiment of the present disclosure. FIG. 2 is a schematic enlarged perspective view of a retraction preventing member of the filtration module of FIG.

[Issues that disclosure is trying to solve]

In the filtration module provided with the flow straightening cylinder as disclosed in Patent Document 1, when the liquid to be treated contains fibrous contaminants, the foreign matter may be entangled and the flow straightening holes of the flow straightening cylinder may be blocked. Once the flow straighteners are blocked by the contaminants, it is not easy to remove the contaminants without disassembling the filtration module.

The present disclosure has been made based on the circumstances as described above, and it is an object of the present disclosure to provide a filtration module capable of easily removing contaminants even if the channel is blocked by the contaminants.
[Effect of the present disclosure]

The filtration module according to an aspect of the present disclosure can easily remove the contaminants even if the channel is blocked by the contaminants.
[Description of the embodiment of the present disclosure]
A filtration module according to an aspect of the present disclosure is a cylinder having a plurality of hollow fiber membranes aligned in one direction, a plurality of hollow fiber membranes, and a concentrate nozzle on a side surface for discharging a concentrate. And a pull-in blocking member inserted into the concentrate nozzle to prevent the hollow fiber membrane from entering the concentrate nozzle.

The filtration module is configured such that the pull-in preventing member for preventing the hollow fiber membrane from entering into the concentrate nozzle is inserted into the concentrate nozzle, whereby contaminants in the liquid to be treated Thus, when the pull-in blocking member is closed, the pull-in blocking member can be pulled out of the concentrate nozzle for cleaning, so that the contaminants can be easily removed and the filtering ability can be recovered.

The pull-in blocking member seals an inner cylindrical portion disposed inside the concentrate nozzle, and a dome-shaped sealed portion having a plurality of openings for sealing the tip of the inner cylindrical portion and allowing the concentrate to pass therethrough. The sealing portion may protrude into the casing, and the plurality of openings may be elongated openings extending toward the tip of the sealing portion. According to this configuration, the sealing portion can be disposed inside the casing by having the inner cylindrical portion disposed inside the concentrate nozzle, so that the hollow fiber by the flow of the concentrate can be obtained. It is possible to more reliably prevent the membrane from being drawn into the concentrate nozzle. Further, the draw-in blocking member is formed in a dome shape that seals the tip of the inner cylindrical portion, thereby increasing the total area of the plurality of openings through which the concentrate passes and securing a sufficient flow path area. be able to. Furthermore, by forming the plurality of openings in the shape of a long hole extending toward the tip of the sealing portion, even if the hollow fiber membrane may come in contact with the openings, the direction in which the openings extend and the hollow fiber membrane Since the direction of extension of the hollow fiber membrane is different from the direction in which the hollow fiber membrane extends, the hollow fiber membrane is less likely to be drawn into the opening, and the opening is not easily closed.

A plurality of the elongated hole-shaped openings may be formed along the longitudinal direction toward the tip of the sealing portion. Thus, the total area of the plurality of openings can be increased by forming a plurality of the elongated hole-like openings in the longitudinal direction toward the tip of the sealing portion.

The sealing portion may have a region where the opening does not exist at the tip in the protruding direction. As described above, the sealing portion has a region where the opening does not exist at the tip in the projecting direction which tends to draw in and close the hollow fiber membrane, thereby more reliably preventing the hollow fiber membrane from being drawn in. It becomes easier to secure the strength of the sealing portion.

The pull-in blocking member may have a locking portion that is locked to the outer end of the concentrate nozzle. In this manner, the pull-in preventing member has a locking portion, and the locking portion is locked to the outer end of the concentrate nozzle, whereby the sealing portion is easily and reliably positioned at an appropriate position. Since the arrangement can be made, the pull-in of the hollow fiber membrane can be prevented more reliably.

Details of Embodiments of the Present Disclosure
Hereinafter, embodiments of the filtration module according to the present disclosure will be described in detail with reference to the drawings.

FIG. 1 shows a filtration module according to an embodiment of the present disclosure. The filtration module includes a membrane element 2 having a plurality of hollow fiber membranes 1 aligned in one direction, and a cylindrical casing 3 for storing the membrane element 2 having the plurality of hollow fiber membranes 1. .

The membrane element 2 has a first holding member 4 holding one end of the plurality of hollow fiber membranes 1 and a second holding member 5 holding the other end of the plurality of hollow fiber membranes 1 . In addition, the membrane element 2 has a connecting member 6 that connects the first holding member 4 and the second holding member 5 and determines the relative position of the two.

The casing 3 has a treatment liquid nozzle 7 to which the treatment liquid is supplied on the end face of one end, and a filtration for discharging the filtrate which has permeated the plural hollow fiber membranes 1 on the end face of the other end. A liquid nozzle 8 is provided, and a concentrated liquid nozzle 9 for discharging a concentrated liquid obtained by subtracting the filtrate from the liquid to be treated is provided on the side near the other end.

The filtration module further includes a pull-in blocking member 10 which is externally inserted into the concentrate nozzle 9 and prevents the hollow fiber membrane 1 from entering the concentrate nozzle 9.

The filtration module prevents the concentrated water from drawing the hollow fiber membrane 1 into the concentrate nozzle 9, and the pull-in prevention member 10 is inserted into the concentrate nozzle 9 from the outside. In the case of blocking by contaminants in the treatment liquid (concentrate), the drawing-in blocking member 10 can be pulled out from the concentrate nozzle 9 to remove contaminants. For this reason, even if the flow path of the concentrate is blocked, the filtration module can easily restore the filtration capacity without decomposing the whole.

Hereinafter, each component of the said filtration module is explained in full detail.

<Filtration element>
The membrane element 2 integrates the plurality of hollow fiber membranes 1 by the first holding member 4, the second holding member 5 and the connecting member 6, and holds the plurality of hollow fiber membranes 1 in one direction in the casing. Make it easy to do.

(Hollow fiber membrane)
The hollow fiber membrane 1 is formed by forming a porous membrane into a tubular shape, which allows the solvent in the liquid to be treated to permeate while blocking the permeation of impurities contained in the liquid to be treated to a certain particle size or more. What has resin as a main component can be used. Here, "main component" means a component with the highest content.

Examples of the thermoplastic resin include polyethylene, polypropylene, polyvinylidene fluoride, ethylene-vinyl alcohol copolymer, polyamide, polyimide, polyetherimide, polystyrene, polysulfone, polyvinyl alcohol, polyphenylene ether, polyphenylene sulfide, cellulose acetate, polyacrylonitrile And polytetrafluoroethylene (PTFE). Among these, PTFE which is excellent in mechanical strength, chemical resistance, heat resistance, weather resistance, nonflammability and the like and is porous is preferable, and uniaxially or biaxially stretched PTFE is more preferable. In addition, other polymers, additives such as a lubricant and the like may be appropriately blended in the forming material of the hollow fiber membrane 1.

The lower limit of the ratio of the average pitch to the average outer diameter of the hollow fiber membrane 1 is preferably 1. On the other hand, the upper limit of the ratio of the average pitch to the average outer diameter of the hollow fiber membrane 1 is preferably 3/2, more preferably 7/5. When the ratio of the average pitch to the average outer diameter of the hollow fiber membrane 1 does not reach the above lower limit, the hollow fiber membrane 1 is disposed in a radially crushed state, so that the production of the membrane element 2 is difficult May be On the other hand, when the ratio of the average pitch to the average outer diameter of the hollow fiber membrane 1 exceeds the above-mentioned upper limit, the density of the hollow fiber membrane 1 becomes small, and there is a possibility that sufficient filtration efficiency can not be obtained.

The lower limit of the average outer diameter of the hollow fiber membrane 1 is preferably 1 mm, more preferably 1.5 mm, and still more preferably 2 mm. On the other hand, the upper limit of the average outer diameter of the hollow fiber membrane 1 is preferably 6 mm, more preferably 5 mm, and still more preferably 4 mm. When the average outer diameter of the hollow fiber membrane 1 does not reach the above lower limit, the mechanical strength of the hollow fiber membrane 1 may be insufficient. On the other hand, when the average outer diameter of the hollow fiber membrane 1 exceeds the above upper limit, the flexibility of the hollow fiber membrane 1 is insufficient, and the vibration and oscillation of the hollow fiber membrane 1 due to the contact of air bubbles become insufficient. There is a possibility that the air gap can not be guided to the central portion of the bundle of hollow fiber membranes 1 by expanding the gap between 1 and that the ratio of the surface area to the cross sectional area of hollow fiber membranes 1 becomes small and the filtration efficiency decreases. .

The lower limit of the average inner diameter of the hollow fiber membrane 1 is preferably 0.3 mm, more preferably 0.5 mm, and still more preferably 0.9 mm. On the other hand, the upper limit of the average inner diameter of the hollow fiber membrane 1 is preferably 4 mm, more preferably 3 mm. When the average inner diameter of the hollow fiber membrane 1 does not reach the above lower limit, the pressure loss when discharging the treated liquid in the hollow fiber membrane 1 may be large. On the other hand, when the average inner diameter of the hollow fiber membrane 1 exceeds the above upper limit, the thickness of the hollow fiber membrane 1 may be reduced, and the mechanical strength and the permeation prevention effect of impurities may be insufficient.

The lower limit of the ratio of the average inner diameter to the average outer diameter of the hollow fiber membrane 1 is preferably 3/10, more preferably 2/5. On the other hand, the upper limit of the ratio of the average inner diameter to the average outer diameter of the hollow fiber membrane 1 is preferably 4/5, more preferably 3/5. If the ratio of the average inner diameter to the average outer diameter of the hollow fiber membrane 1 does not reach the above lower limit, the thickness of the hollow fiber membrane 1 may be increased more than necessary and the liquid permeability of the hollow fiber membrane 1 may be reduced. On the other hand, when the ratio of the average inner diameter to the average outer diameter of the hollow fiber membrane 1 exceeds the above upper limit, the thickness of the hollow fiber membrane 1 may be reduced and the mechanical strength and the permeation inhibition effect of impurities may be insufficient. .

(First holding member)
The first holding member 4 airtightly holds the end of one side of the plurality of hollow fiber membranes 1 and opens the end of one side of the plurality of hollow fiber membranes 1 and the end of one side of the casing 3 By airtightly engaging the inner wall in the vicinity of the portion, the space in the casing 3 is divided, and a small space communicating with the lumens of the plurality of hollow fiber membranes 1 is formed on one side.

The first holding member 4 defines an engagement shape to be engaged with the casing 3 and a support having a plurality of through holes for positioning one end of the plurality of hollow fiber membranes 1, and the support It can be set as the composition which has a filler with which a crevice with a plurality of hollow fiber membranes 1 is filled.

As a material of the said support body, the resin composition which has a PTFE, a polyvinyl chloride, polyethylene, an ABS resin etc. as a main component is mentioned, for example.

As the filler, any material may be used as long as it has high adhesion to the hollow fiber membrane 1 and can be cured in the support. In particular, when using PTFE as the main component of the hollow fiber membrane 1, epoxy resin and polyurethane having high adhesiveness to PTFE and capable of reliably preventing the hollow fiber membrane 1 from falling off are preferable as the main component of the filler. . By filling the support with the filler, the space between the hollow fiber membrane 1 and the support can be airtightly sealed, and the non-filtered liquid to be treated is filtered from the outside from the outside. It can prevent mixing.

(Second holding member)
The second holding member 5 holds the end portions of the plurality of hollow fiber membranes 1 on the other side, and holds the plurality of hollow fiber membranes 1 in one direction without being entangled. The second holding member 5 holds the other end of the plurality of hollow fiber membranes 1 so as not to open the internal space of the hollow fiber membrane 1. Further, the second holding member 5 does not separate the internal space on both sides in the aligning direction of the hollow fiber membranes 1 of the casing 3 so that a gap is formed between the second holding member 5 and the inner wall of the casing 3 or the treatment liquid can pass. Configured to have an opening.

The second holding member 5 is filled in the gap between the support and the hollow fiber membranes 1 and the support having a plurality of non-through holes for positioning the other end of the hollow fiber membranes 1. It can be set as the composition which has a filler.

The material of the support of the second holding member 5 and the material of the filler may be the same as the material of the support of the first holding member 4 and the filler.

(Connection member)
The connecting member 6 connects the first holding member 4 and the second holding member 5 which are vertically opposed to each other, and holds the second holding member 5 at a predetermined position in the casing 3. Further, the connecting member 6 integrates the first holding member 4 and the second holding member 5 and the plurality of hollow fiber membranes 1 disposed therebetween to facilitate disassembly and assembly of the filtration module.

For example, a support rod made of resin or metal can be used as the connection member 6.

<Casing>
The casing 3 is provided with a cylindrical main body 11 and a first sleeve 12 mounted at one end of the main body 11 and provided with an engaging structure in which the concentrate nozzle 9 and the first holding member 4 are engaged. A first cap 13 sealing the end of the sleeve 12 opposite to the main body 11 and provided with the filtrate nozzle 8; and a second sleeve 14 attached to the other end of the main body 11; An end of the second sleeve 14 opposite to the main body 11 is sealed, and a second cap 15 provided with the liquid processing nozzle 7 can be provided.

With such a configuration, for example, a commercially available pipe or the like can be used as the main body 11, so the length of the hollow fiber membrane 1 to be used, that is, the filtration area can be selected relatively freely. In particular, by separately forming the main body 11 and the first sleeve 12, the engagement structure with the nozzle 9 and the first holding member 4 can be formed accurately and inexpensively.

In addition, by configuring the first cap 13 and the second cap 15 to be attachable to and detachable from the first sleeve 12 and the second sleeve 14, respectively, the filtration module can be disassembled and cleaned. As a mounting and demounting structure of the first cap 13 and the second cap 15, for example, a screw, a flange, a ferrule, or any other structure used as a pipe joint can be adopted.

Examples of the material of each component of the casing 3 include metals such as iron, stainless steel, aluminum and the like, for example, resin compositions mainly composed of PTFE, polyvinyl chloride, polyethylene, ABS resin, etc. Different materials may be adopted for each component.

The liquid nozzle 7, the filtrate nozzle 8 and the concentrate nozzle 9 have a joint structure in which piping can be connected to the outer end. As the joint structure, a flange, a ferrule or the like may be adopted in addition to the external screw as shown.

<Retraction blocking member>
The retraction prevention member 10 is shown in detail in FIG. The pull-in blocking member 10 is engaged with the inner cylindrical portion 16 disposed inside the concentrate nozzle 9, the sealing portion 17 sealing the tip of the inner cylindrical portion 16, and the outer end of the concentrate nozzle 9. And a locking portion 18 to be stopped.

The pull-in blocking member 10 is connected to the joint structure of the concentrate nozzle 9 and fixed in an inserted state in the concentrate nozzle 9 by a mounting member 19 that presses the locking portion 18 against the outer end of the concentrate nozzle 9. Ru.

(Inner cylinder)
The inner cylindrical portion 16 is preferably formed in a tubular shape having an outer diameter having a minimum degree of clearance with the inner wall surface of the concentrate nozzle 9 so as to be able to be inserted into and removed from the concentrate nozzle 9. Further, the inner cylindrical portion 16 may be slightly reduced in diameter toward the sealing portion 17 in order to be able to be integrally formed with the sealing portion 17 and the locking portion 18 by injection molding.

The inner cylindrical portion 16 may be connected to the end of the pipe for discharging the concentrate, and is fixed in the concentrate nozzle 9 by the mounting member 19 connected to the end of the pipe for discharging the concentrate. May be

The average thickness of the inner cylindrical portion 16 may be any thickness as long as sufficient strength can be ensured, and may be, for example, 2 mm or more and 10 mm or less, although it depends on the material.

(Sealing part)
The sealing portion 17 is formed in a dome shape and has a plurality of openings 20 through which the concentrate passes. Further, the sealing portion 17 protrudes into the casing 3. In addition, "dome shape" means the whole shape which does not have the corner | angular shape which expanded smoothly, such as spherical shape, elliptical spherical shape, the conical surface shape which chamfered the top, etc., for example.

By forming the sealing portion 17 in a dome shape, it becomes difficult to damage the hollow fiber membrane 1 even when contacting the hollow fiber membrane 1, and the total area of the openings 20 is increased to ensure a sufficient flow path area can do.

The sealing portion 17 preferably has a region where the opening 20 does not exist at the tip in the protruding direction. Thus, damage to the hollow fiber membrane 1 can be more reliably prevented by having a region where the opening 20 does not exist at the tip in the projecting direction that is easily in contact with the hollow fiber membrane 1. In addition, since the tip of the sealing portion 17 in the protruding direction is a plane substantially parallel to the extending direction of the hollow fiber membrane 1, the hollow fiber membrane 1 is easily sucked by the flow of the concentrate, and the hollow fiber membrane 1 is sucked. Contaminants are easily attached to the opening 20 having a smaller area, and by not forming the opening 20 in this region, attachment of contaminants can be suppressed.

The thickness of the sealing portion 17 may be a thickness that can ensure sufficient strength, but may be slightly smaller than the inner cylinder portion 16 in order to increase the flow passage area. The average thickness of the sealing portion 17 may be, for example, 2 mm or more and 10 mm or less, although it depends on the material.

The opening 20 of the sealing portion 17 is preferably formed in a long hole shape extending toward the tip of the sealing portion 17. Thus, even if the hollow fiber membrane 1 is in contact with the opening 20 by the opening 20 being an elongated hole extending toward the tip of the sealing portion 17, the direction in which the opening 20 extends and the hollow fiber membrane Because the direction in which 1 extends is different from the direction in which it extends, the hollow fiber membrane 1 is less likely to close the opening.

Further, it is more preferable that a plurality of openings 20 be formed in the sealing portion 17 in the longitudinal direction toward the tip of the sealing portion 17. If a long long hole extending from the vicinity of the inner cylindrical portion 16 of the sealing portion 17 to the vicinity of the tip of the sealing portion 17 is formed, the strength of the sealing portion 17 may be insufficient. By dividing and forming into two, it becomes easy to secure the strength of the sealing portion 17. For this reason, by forming the plurality of openings 20 side by side in the longitudinal direction, the aperture ratio in the circumferential direction of the sealing portion 17 can be increased, so that the total area of the plurality of openings 20 can be increased.

The opening 20 is preferably chamfered at least on the outer peripheral side of the sealing portion 17 so as not to be damaged even when the hollow fiber membrane 1 contacts.

The lower limit of the minor diameter (the width of the portion where the width of the elongated hole is constant) of the opening 20 is preferably 3 mm, more preferably 5 mm. On the other hand, as an upper limit of the breadth of

opening

20, 12 mm is preferred and 10 mm is more preferred. If the minor axis of the opening 20 does not reach the above lower limit, the opening 20 may be easily clogged by contaminants. On the other hand, when the minor axis of the opening 20 exceeds the above upper limit, the hollow fiber membrane is easily drawn into the opening, and the opening may be blocked.

As a minimum of a major axis (length of a long hole) of

opening

20, 10 mm is preferred and 15 mm is more preferred. On the other hand, as a maximum of a major axis of opening 20, 30 mm is preferred and 25 mm is more preferred. If the major diameter of the opening 20 does not reach the above lower limit, the area ratio of the opening 20 in the sealing portion 17 can not be increased, and the flow passage area may not be sufficiently increased. On the other hand, when the major diameter of the opening 20 exceeds the above-mentioned upper limit, there is a possibility that it will become difficult to secure the intensity of the sealing part 17.
As a lower limit of the total opening area of the plurality of openings 20, 110% of the cross-sectional area in the inner cylinder part 16 is preferable, and 130% is more preferable. On the other hand, as an upper limit of the total opening area of the plurality of openings 20, 180% of the cross-sectional area in the inner cylinder part 16 is preferable, and 160% is more preferable. If the total opening area of the plurality of openings 20 does not reach the above lower limit, the openings 20 may be easily clogged by foreign matter. On the other hand, when the total opening area of the plurality of openings 20 exceeds the above upper limit, the strength of the sealing portion 17 may be insufficient, or the sealing portion 17 may be too large and easily interfere with the hollow fiber membrane 1 May be

(Locking part)
The locking portion 18 protrudes outward from the inner cylindrical portion 16 and abuts on the outer end of the concentrate nozzle 9 to thereby determine the position of the pull-in blocking member 10 with respect to the casing 3. As a result, the pull-in blocking member 10 can be fixed at an appropriate position, and pull-in of the hollow fiber membrane 1 to the concentrate nozzle 9 can be more reliably prevented.

The locking portion 18 may be protruded only on a part of the outer periphery of the inner cylinder portion 16, but in order to seal airtight between the concentrate nozzle 9 and the like, the entire periphery of the inner cylinder portion 16 is sealed. It is preferable to be provided in a ring shape. The locking portion 18 may have a holding structure that holds a sealing member such as an O-ring 21 that seals between the locking portion 18 and the outer end of the concentrate nozzle 9.

<Mounting member>
The mounting member 19 has a joint structure corresponding to the joint structure of the liquid nozzle 7 and holds the locking portion 18 in contact with the outer end of the concentrate nozzle 9. The configuration of the mounting member 19 can be a flange, a ferrule or the like in addition to a union nut as shown.

Depending on the joint structure of the liquid nozzle 7, a part or all of the attachment member 19 may be integrally formed with the pull-in preventing member 10.

Other Embodiments
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is not limited to the configurations of the above embodiments, but is indicated by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. Ru.

In the filtration module, the configuration of the membrane element having a plurality of hollow fiber membranes is arbitrary. Also, a plurality of hollow fiber membranes may be permanently disposed in the casing without forming a detachable membrane element.

The pull-in blocking member of the filtration module may be any one that can allow the concentrate to flow out to the concentrate nozzle and prevent the hollow fiber membrane from entering into the concentrate nozzle, and the inner cylinder part and the seal It is not restricted to what has a part. Moreover, the latching | locking part in a drawing-in prevention member is also arbitrary structures.

DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane 2 Membrane element 3 Casing 4 First holding member 5 Second holding member 6 Connection member 7 Treated liquid nozzle 8 Filtrate nozzle 9 Concentrated liquid nozzle 10 Pull-in blocking member 11 Body 12 First sleeve 13 First cap 14 Second sleeve 15 Second cap 16 Inner cylindrical portion 17 Sealing portion 18 Locking portion 19 Mounting member 20 Opening 21 O-ring

Claims

A plurality of hollow fiber membranes aligned in one direction;
A cylindrical casing having at its side a concentrate nozzle for storing the plurality of hollow fiber membranes and discharging a concentrate;
A filtration prevention member inserted into the concentrate nozzle to prevent the hollow fiber membrane from entering the concentrate nozzle.
The pull-in blocking member is
An inner cylindrical portion disposed inside the concentrate nozzle;
And a dome-shaped sealing portion having a plurality of openings for sealing the tip of the inner cylindrical portion and allowing the concentrate to pass therethrough;
The sealing portion projects into the casing;
The filtration module according to claim 1, wherein the plurality of openings are oblong openings extending toward the tip of the sealing portion.
The filtration module according to claim 2, wherein a plurality of the elongated hole-shaped openings are formed in a longitudinal direction toward the tip of the sealing portion.
The filtration module according to claim 2 or 3, wherein the sealing portion has a region where the opening does not exist at the tip of the sealing portion.
The filtration module according to any one of claims 1 to 4, wherein the pull-in preventing member has a locking portion that is locked to the outer end of the concentrate nozzle.