JP7294352B2 - Hollow fiber membrane element and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a hollow fiber membrane element and a method for producing the same.
This application claims priority based on Japanese Patent Application No. 2018-222747 filed in Japan on November 28, 2018, the contents of which are incorporated herein.

Hollow fiber membrane elements are widely used in the production of sterile water, drinking water, highly pure water, and the like. As a hollow fiber membrane element, for example, a hollow fiber membrane is provided with water collection pipes at both ends in the length direction, and tubular struts connected in communication with the water collection pipes are known (Patent Reference 1).

In the hollow fiber membrane element as disclosed in Patent Document 1, both ends of the water collection tube are provided with tubular protrusions that communicate with the water collection section for fitting and connecting to the ends of the tubular struts. In the production of the hollow fiber membrane element, for example, a resin is injected around the protrusions, and the end of the tubular support is inserted into the end of the water collecting pipe, and then the resin is cured. Since the gap between the protrusion and the tubular support is filled with the resin, a hollow fiber membrane element having excellent watertightness at the connecting portion between the end portions of the water collection tube and the tubular support can be obtained.

Chinese Utility Model No. 202006088

In the hollow fiber membrane element described in Patent Document 1, while suppressing the resin from entering the water collecting portion during manufacturing, the connecting portions between the ends of the projections and the tubular struts are sufficiently watertightly sealed with resin. requires multiple injections and curing of the resin. Specifically, after adjusting the amount of resin so that the resin surface injected into the water collecting pipe does not exceed the height of the protrusion, insert the tubular support, and after curing the resin once, make sure that the amount of resin is sufficient. Inject more resin and harden it.

As described above, conventional hollow fiber membrane elements require resin injection and curing in multiple steps, which complicates the work, lowers production efficiency, and increases the curing time, resulting in a long production time. , was less productive.

An object of the present invention is to provide a hollow fiber membrane element having tubular struts on both sides in the width direction of a hollow fiber membrane sheet and having high production efficiency and excellent productivity, and a method for producing the same.

In a conventional hollow fiber membrane element, the protrusion is provided as a guide for the fixing position when fixing the tubular support to the water collecting pipe. Therefore, it has been thought that lower protrusions are preferable so that the tubular struts can be easily installed on the water collecting pipe. However, the inventors of the present invention have completed the present invention by discovering that manufacturing efficiency can be improved by increasing the height of the protrusions, regardless of the conventional purpose of the protrusions.
Specifically, in the present invention, the height of the tubular projections arranged on the water collecting pipe is set to 40% or more of the lowest portion of the peripheral wall surrounding the projections. As a result, it was possible to reduce the number of times of injecting and hardening the potting material for fixing the water collecting pipe and the tubular support, and it was possible to improve the manufacturing efficiency and productivity. That is, the present invention has the following configurations.

[1] a plurality of hollow fiber membranes;
a first water collection pipe and a second water collection pipe respectively provided on the first opening end side and the second opening end side in the length direction of the hollow fiber membrane;
a tubular support having both ends connected to the first water collection pipe and the second water collection pipe;
with
The first open end and the second open end of the hollow fiber membrane are inserted into the first water collection pipe and the second water collection pipe, respectively, with the end faces of the hollow fiber membranes being open,
At least one of the first water collection pipe, the second water collection pipe, and the tubular support is formed with at least one outlet for taking out treated water,
The first water collecting pipe and the second water collecting pipe are provided with tubular projections for connecting with the tubular struts communicating with the water collecting portions inside the first water collecting pipe and the second water collecting pipe. ,
A peripheral wall portion surrounding the projection is provided,
the protrusion is located within the end of the tubular strut;
The height of the projection is 40% or more of the height of the lowest portion of the peripheral wall,
The inside of the tubular support and the water collecting portions inside the first water collecting pipe and the second water collecting pipe are in communication via the inside of the projection,
Hollow fiber membrane element.
[2] The hollow fiber membrane element according to [1], wherein the tubular support and the first and second water collection tubes are fixed in a watertight manner.
[3] The gap between the tubular post and the projection at the insertion portion where the projection is inserted into the end of the tubular post is fixed in a watertight manner with a potting material, [1] or [ 2].
[4] The protrusion is composed of a tubular protrusion communicating with the water collecting portion inside the first water collection pipe and the second water collection pipe, and a tubular sleeve connected to the protrusion, [ 1] The hollow fiber membrane element according to any one of [3].
[5] The hollow fiber membrane element according to [4], wherein a portion of the tubular sleeve on the projecting portion side is inserted inside the projecting portion.
[6] The hollow fiber membrane according to [5], wherein a step is formed on the outer surface of the tubular sleeve so that a portion of the tubular sleeve that is not inserted into the protrusion protrudes from a portion that is inserted into the protrusion. element.
[7] The hollow fiber membrane element according to [5] or [6], wherein the protrusion and the tubular sleeve form a fitting structure.
[8] The hollow fiber membrane element according to any one of [1] to [7], wherein the protrusions are tapered toward their tips.
[9] The hollow fiber membrane element according to any one of [1] to [3], wherein the protrusions are formed integrally with the first water collecting pipe and the second water collecting pipe.
[10] The projection according to any one of [1] to [3], wherein the projection is composed of a tubular sleeve connected to openings provided in the first water collection pipe and the second water collection pipe. Hollow fiber membrane element.
[11] The hollow fiber membrane element according to any one of [1] to [10], wherein the outer surface of the ends of the tubular struts is blasted.
[12] A first closing portion that blocks the flow of treated water that has flowed into the water collecting portion of the first water collecting pipe through the first open end portion of the hollow fiber membrane to the tubular support. and/or the second water collection pipe is provided with a second open end of the hollow fiber membrane to block the flow of treated water into the water collection portion of the second water collection pipe to the tubular strut. The hollow fiber membrane element according to any one of [1] to [11], which is provided with a second closing portion.
[13] a plurality of hollow fiber membranes;
a first water collection pipe and a second water collection pipe respectively provided on a first opening end side and a second opening end side of the hollow fiber membrane in the length direction of the hollow fiber membrane;
a tubular support having both ends connected to the first water collection pipe and the second water collection pipe;
with
The first open end and the second open end of the hollow fiber membrane are inserted into the first water collection pipe and the second water collection pipe, respectively, with the end faces of the hollow fiber membranes being open,
The inside of the tubular support and the water collecting portions inside the first water collecting pipe and the second water collecting pipe are communicated,
The tubular support and the first and second water collecting pipes are fixed in a watertight manner,
the outer surface of the end of the tubular strut is blasted;
Hollow fiber membrane element.
[14] A method for producing the hollow fiber membrane element according to [1],
A method for manufacturing a hollow fiber membrane element, wherein the protrusions are inserted into the ends of the tubular struts.
[15] The method for producing a hollow fiber membrane element according to [14], wherein the tubular strut and the first and second water collecting tubes are fixed in a watertight manner.

According to the present invention, it is possible to provide a hollow fiber membrane element having tubular struts on both sides in the width direction of a hollow fiber membrane sheet and having high production efficiency and excellent productivity, and a method for producing the same.

1 is a perspective view showing an example of a hollow fiber membrane element of the present invention; FIG. FIG. 2 is a front view of the hollow fiber membrane element of FIG. 1; FIG. 3 is a cross-sectional view of the hollow fiber membrane element of FIG. 2 taken along line AA. FIG. 2 is a BB cross-sectional view of the hollow fiber membrane element of FIG. 1; 5 is another embodiment of the hollow fiber membrane element of FIG. 5 is still another embodiment of the hollow fiber membrane element of FIG. 4. FIG. 5 is a modification of the hollow fiber membrane element of FIG. 4. FIG. FIG. 5 is a CC cross-sectional view of the hollow fiber membrane element of FIG. 4;

[Hollow fiber membrane element]
An example of the hollow fiber membrane element of the present invention will be described below with reference to the drawings. It should be noted that the dimensions and the like in the drawings illustrated in the following description are examples. The invention is not limited to the following description. The present invention can be modified and implemented as appropriate without changing the gist thereof.

As shown in FIGS. 1 and 2, the hollow fiber membrane element 1 of the present embodiment includes a hollow fiber membrane sheet 10, a first water collecting pipe 12, a second water collecting pipe 14, and tubular struts 16 (18). and

The hollow fiber membrane sheet 10 is obtained by bundling a plurality of hollow fiber membranes 11 into a sheet. The first water collection pipe 12 is provided on the side of the first open end 10a in the longitudinal direction of the hollow fiber membranes 11 of the hollow fiber membrane sheet 10 . The second water collecting pipe 14 is provided on the side of the second open end 10b opposite to the first open end 10a in the length direction of the hollow fiber membrane sheet 10 .

The tubular support 16 is provided on one side of the hollow fiber membrane sheet 10 in the width direction. A first end 17a of the tubular strut 16 is connected to a first end 13a of the first collecting pipe 12 . The second end 17b of the tubular strut 16 is connected to the first end 15a of the second water collecting pipe 14 .
The tubular support 18 is provided on the other side of the hollow fiber membrane sheet 10 in the width direction. A first end 19 a of the tubular strut 18 is connected to a second end 13 b of the first collecting pipe 12 . A second end 19b of the tubular strut 18 is connected to a second end 15b of the second collecting pipe 14 .
The hollow fiber membrane element 1 is arranged so that the first water collection pipe 12 is on the bottom side, the second water collection pipe 14 is on the top side, and the length direction of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 is the vertical direction. It is

The hollow fiber membrane sheet 10 is formed by bundling a plurality of hollow fiber membranes 11 in parallel to form a sheet. The number of hollow fiber membranes 11 in the hollow fiber membrane sheet 10 is not particularly limited, and can be, for example, 1,000 to 2,000.
The hollow fiber membrane sheet material 10 of this example is a laminate in which a plurality of sheets each having a plurality of hollow fiber membranes 11 aligned are laminated. In the present invention, the hollow fiber membrane sheet may be a laminate of a plurality of such sheets, or may consist of a single sheet.

Materials for the hollow fiber membrane include, for example, polysulfone-based resins, polyacrylonitrile, cellulose derivatives, polyolefins such as polyethylene and polypropylene, fluorine-based resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene, polyamides, polyesters, and polymethacrylates. , polyacrylate and the like. Moreover, you may use what introduce|transduced the substituent into the part of these resin. The material of the hollow fiber membrane may be of one type or two or more types.

For example, using a plurality of hollow fiber membranes 11, a hollow fiber membrane sheet may be formed by the method for producing a hollow fiber membrane sheet described in Japanese Patent No. 5919672 and used.

The first water collecting pipe 12 has an opening 20d extending in the longitudinal direction between the first end 13a and the second end 13b. The end portion 10a is adapted to be inserted.
Specifically, the portion between the first end portion 13a and the second end portion 13b in the first water collecting pipe 12 of this example is a pair of long lengths whose surfaces face each other, as shown in FIG. Side walls 20a and 20b are provided. A portion between the first end portion 13a and the second end portion 13b of the first water collecting pipe 12 of this example is provided with a bottom portion 20c having a semicircular cross section connecting one end portions of the side wall portions 20a and 20b. . A slit-shaped opening 20d extending in the longitudinal direction is formed on the side of the first water collecting pipe 12 opposite to the bottom portion 20c. The shape of the cross section orthogonal to the longitudinal direction of the first water collecting pipe 12 is U-shaped.

The first open end 10a of the hollow fiber membrane sheet 10 is inserted into the opening 20d of the first water collecting pipe 12 with the end face of each hollow fiber membrane 11 open. In the first water collecting pipe 12, the first opening end portion 10a of the hollow fiber membrane sheet 10 is a potting portion 22a made of a cured potting material in a state where the end faces of the hollow fiber membranes 11 are open. Fixed. Further, the bottom portion 20c side of the potting portion 22a in the first water collecting pipe 12 is a water collecting portion 20e.

As shown in FIGS. 4 and 8, the first end 13a of the first water collecting pipe 12 has a tubular portion 24a communicating with the water collecting portion 20e. The first end portion 13a of the first water collecting pipe 12 has a tubular protrusion 29 positioned so as to protrude toward the opening 20d of the first water collecting pipe 12 . The first end portion 13a of the first water collecting pipe 12 has a peripheral wall portion 24c positioned so as to surround the projection 29 on all four sides.

The peripheral wall portion 24c is for blocking the leakage of the potting material 30 from the opening 20d of the first water collecting pipe 12 when the tubular strut 16 is fixed. A potting material 30 is dispensed around the insert where the tubular strut 16 is inserted into the projection 29 and the projection 29 is inserted into the first end 17a of the tubular strut 16 .

Two of the four peripheral wall portions 24c surrounding the four sides of the projection 29 are provided on both sides in the longitudinal direction of the water collecting pipe of the projection 29 on the cylindrical portion 24a and are spaced apart from the projection 29 and opposed to each other. . The remaining two of the four peripheral wall portions 24c are provided on both sides of the projection 29 on the tubular portion 24a in the lateral direction of the water collecting pipe, spaced apart from the projection 29 and facing each other. , 20b is a continuous wall. Of the four peripheral wall portions 24c surrounding the projecting portion 24b, the upper end on the central side in the longitudinal direction of the first water collecting pipe 12 is slightly lower than the upper ends of the side wall portions 20a and 20b. The upper end of the first water collection pipe 12 on the center side in the longitudinal direction is the peripheral wall portion 24c on the side closer to the first open end portion 10a of the hollow fiber membrane sheet 10 . In addition, the remaining three peripheral wall portions 24c, that is, the peripheral wall portion 24c on the end surface side of the first water collection pipe 12 and the upper ends of the pair of peripheral wall portions 24c opposed in the lateral direction are at the same height as the upper ends of the side wall portions 20a and 20b. It has become.

A modified example of the peripheral wall portion 24c is, for example, without the peripheral wall portion 24c on the side closer to the first open end 10a of the hollow fiber membrane sheet 10 as shown in FIG. The peripheral wall portion 24c on the end surface side of the first end portion 13a and the second end portion 13b of the first water collecting pipe 12 and the side wall portions 20a and 20b are integral and continuous walls. This integral continuous wall can block the potting material 30 from leaking out from the opening 20 d of the first water collecting pipe 12 when the tubular strut 16 is fixed. A potting material 30 is dispensed around the insert where the tubular strut 16 is inserted into the projection 29 and the projection 29 is inserted into the first end 17a of the tubular strut 16 .

A tubular protrusion 29 located at the first end 13 a of the first water collecting pipe 12 is a portion for connecting with the tubular support 16 . The inside of the protrusion 29 communicates with the inside of the tubular portion 24a. The shape of the projection 29 is not particularly limited, and examples thereof include a square tubular shape, a cylindrical shape, and the like.

The height D of the projection 29 is 40% or more, preferably 55% or more, more preferably 70% or more, and even more preferably 90% or more of the height E of the lowest portion of the peripheral wall portion 24c. The upper limit of the height D of the protrusion 29 is not particularly limited, but the height D of the protrusion 29 is preferably 150% or less, more preferably 130% or less, and 110% or less of the height of the lowest portion of the peripheral wall portion 24c. More preferred. Here, the height D of the protrusion 29 is the height from the lower end of the tubular support 16 to the upper end of the protrusion 29 when the tubular support 16 is inserted into the protrusion 29 .

The height E of the lowest portion of the peripheral wall portion 24c is the vertical distance from the lower end of the height D of the projection 29 to the top surface of the lowest portion. In the present invention, the lowest portion of the peripheral wall portion 24c is placed so that the volume of liquid that can be retained inside the portion surrounded by the peripheral wall portion of the water collecting pipe is maximized, and when the liquid is poured in, the first This is where the liquid overflows.

When the height D of the protrusion 29 is equal to or higher than the lower limit of the above range, the protrusion and the tubular support are adhered to each other, making it easy to create an element structure having high rigidity at the time of completion by potting once.
If the height D of the protrusion 29 is equal to or less than the upper limit of the above range, the water collecting pipe and the tubular sleeve can be easily formed, and the portion not adhered to the tubular strut is reduced, so that the parts can be effectively used without waste.
The presence of the projections widens the bonding area between the tubular struts and the projections, increasing the bonding strength.

The protrusion is preferably formed integrally with the water collecting pipe. This shortens the process and has the effect of reducing labor, production time, investment, and consumables.

The aspect of the second end 13b of the first water collection pipe 12 is the same as the aspect of the first end 13a, and is provided with a tubular projection 29 for connecting with the tubular strut 18, and the preferred aspect is also the same. .

The aspect of the second water collection pipe 14 includes aspects similar to those of the first water collection pipe 12, and the preferred aspects are also the same. The second open end 10b of the hollow fiber membrane sheet 10 is inserted into the slit-like opening of the second water collecting pipe 14, and fixed by a potting part with the end face of each hollow fiber membrane 11 open. . Further, the first end 15a and the second end 15b of the second water collecting pipe 14 are provided with tubular protrusions 29 for connecting with the tubular struts 16 and 18, respectively.

As shown in FIGS. 4 and 8, the first end 13a of the first water collecting pipe 12 is provided with a tubular protrusion 24b. The projecting portion 24b is a portion for connecting with the tubular strut 16. As shown in FIG. The inside of the projecting portion 24b communicates with the inside of the cylindrical portion 24a. The shape of the projecting portion 24b is not particularly limited, and examples thereof include a square tubular shape, a cylindrical shape, and the like.

The height of the protrusion 24b is preferably 5 to 30 mm, more preferably 10 to 20 mm. If the height of the projecting portion 24b is equal to or higher than the lower limit value of the above range, the connection strength between the projecting portion 24b and the tubular support 16 can be easily increased. If the height of the protrusions 24b is equal to or less than the upper limit of the above range, moldability will be more excellent.
Moreover, the height of the protrusion 24b is preferably 50% or less of the height of the peripheral wall 24c. If the height of the projection 24b is 50% or less of the height of the peripheral wall 24c, the moldability of the water collecting pipe and the projection is excellent.

The second end portion 13b of the first water collection pipe 12 is also provided with a tubular protrusion for connecting with the tubular support 18, similarly to the first end portion 13a.

The first end 15a and the second end 15b of the second water collection pipe 14 are also connected to the tubular struts 16 (18) in the same way as the first end 13a and the second end 13b of the first water collection pipe 12. A tubular projection is provided for.
The presence of the protrusions is preferable in that the bonding area between the tubular support and the protrusions is increased and the bonding strength is improved.

The protrusion 29 on the first end 13a of the first water collecting pipe 12 is composed of a protrusion 24b and a tubular sleeve 26. As shown in FIG. It is inserted into the first end 17a of the tubular post 16 with the tubular sleeve 26 attached to the projection 24b. Thereby, the first end 17a of the tubular strut 16 and the first end 13a of the first water collecting pipe 12 are connected. The inside of the tubular strut 16 and the water collecting portion 20e inside the first water collecting pipe 12 communicate with each other through the inside of the projection 29. As shown in FIG.

Similarly, the projection of the second end 13b of the first collecting pipe 12 is inserted into the first end 19a of the tubular strut 18 with a tubular sleeve attached to the projection. The inside of the tubular strut 18 and the water collection portion 20e inside the first water collection pipe 12 communicate with each other through the inside of the projection. A first end portion 19a of the tubular support 18 and a second end portion 13b of the first water collecting pipe 12 are connected.

The projection of the first end 15a of the second collecting pipe 14 is inserted into the second end 17b of the tubular strut 16 with a tubular sleeve attached to the projection. The inside of the tubular strut 16 and the water collection portion 20f inside the second water collection pipe 14 communicate through the inside of the projection. The second end 17b of the tubular support 16 and the first end 15a of the second water collecting pipe 14 are connected.

The projection of the second end 15b of the second collecting pipe 14 is inserted into the second end 19b of the tubular strut 18 with a tubular sleeve attached to the projection. The inside of the tubular strut 18 and the water collection portion 20f inside the second water collection pipe 14 communicate through the inside of the projection. The second end 19b of the tubular support 18 and the second end 15b of the second water collecting pipe 14 are connected.

The protrusion may comprise a tubular sleeve connected to apertures provided in the first and second collecting pipes.
When the protrusion is composed of a tubular sleeve, when applying an adhesive for adhering the tubular sleeve to the water collection pipe, the adhesive can be applied to the horizontal surface of the water collection pipe, which is preferable in terms of good workability.
Further, when the projection is composed of a tubular sleeve, it is preferable that the length of the tubular sleeve is 10% or more longer than the height of the projection. This is due to the adhesive margin that secures the tubular sleeve to the collecting pipe. The bonding margin increases the bonding area, increases the strength of the hollow fiber membrane element, and facilitates the positioning of the tubular sleeve.

At least one of the first water collecting pipe 12, the second water collecting pipe 14 and the tubular support 16 (18) is formed with an outlet for taking out the treated water. The outlet is preferably formed in the end face of at least one of the first water collecting pipe 12 and the second water collecting pipe 14 . The opening 24d of the tubular portion 24a is closed by the lid member 25 on the end surface of the first water collecting pipe 12 of this example on the side of the first end portion 13a. The opening of the end face of the water collecting pipe can be used as an outlet for taking out the treated water without being closed by the cover member.

As a material for the water collecting pipe, a material having excellent mechanical strength and durability is preferable. Examples thereof include polycarbonate, polysulfone, polyolefin, PVC (polyvinyl chloride), acrylic resin, ABS resin, and modified PPE (polyphenylene ether). The material of the water collecting pipe may be of one type or two or more types.

The shape of the tubular strut is not particularly limited, and examples thereof include a square tubular shape, a cylindrical shape, and the like.
The material of the tubular strut is not particularly limited, and examples thereof include stainless steel (SUS).

Examples of the potting material for forming the potting portion include resins such as epoxy resins, unsaturated polyester resins, polyurethane resins, silicone fillers and various hot-melt resins, and hydraulic cements such as Portland cement and mixed cement. is mentioned. One type of potting material may be used, or two or more types may be used.

Hereinafter, as shown in FIGS. 4 and 8, the projection 29 disposed at the first end portion 13a of the first water collecting pipe 12 is in a state where the tubular sleeve 26 is attached to the projection portion 24b, and the projection 29 is The insert portion 28 inserted within the first end 17a of the tubular strut 16 will now be described in greater detail.

The protrusion provided at the second end portion 13b of the first water collection pipe 12 is in a state where a tubular sleeve is attached to the protrusion. The projection disposed on the first end portion 15a of the second water collection pipe 14 is in a state where a tubular sleeve is attached to the projection. The protrusion provided at the second end 15b of the second water collecting pipe 14 is in a state where a tubular sleeve is attached to the protrusion. An insert portion having a projection inserted into the first end 19a of the tubular strut 18, an insert portion having a projection inserted into the second end 19b of the tubular strut 18, and a second end 19b of the tubular strut 18. The insertion portion in which the protrusion is inserted has the same aspect as the insertion portion 28 described below, and the preferred aspects are also the same.

The shape of the tubular sleeve 26 is not particularly limited, and examples thereof include a square tubular shape, a cylindrical shape, and the like. In this example, a portion of the tubular sleeve 26 on the projecting portion 24b side is inserted into the projecting portion 24b so as to be attached to the projecting portion 24b.
The tubular sleeve 26 preferably has a length of 10 mm or more. If the length of the tubular sleeve 26 is 10 mm or more, the tubular sleeve 26 can be easily gripped and handled when the hollow fiber membrane element is produced.
The length ratio of the tubular sleeve 26 and the protrusion 24b, which constitute the protrusion 29, is generally 1:0.1 to 1:10, preferably 1:0.2 to 1:5, more preferably 1:0. 5 to 1:2. When the length of the protrusion 24b with respect to the tubular sleeve 26 is within the above range, the effect of installing the tubular sleeve 26 can be easily obtained, and the strength of the protrusion 29 against lateral force can be easily ensured.

The cross-sectional shape perpendicular to the axial direction of the portion of the tubular sleeve 26 that is inserted into the protrusion 24b is not particularly limited as long as it is within the range that it can be inserted into the protrusion 24b. For example, it may have a square tubular shape or a cylindrical shape. A mode in which a portion of the cylindrical tubular sleeve 26 on the protruding portion 24b side is inserted into the rectangular tubular protruding portion 24b may be employed. Alternatively, a portion of the tubular sleeve 26 in the shape of a square tube on the side of the protrusion 24b may be inserted into the cylindrical protrusion 24b.

In the present invention, since the position of the height of the protrusion can be accurately determined and the adhesive can be left standing without being supported after application, the tubular sleeve 26 is placed on the side of the protrusion 24b as in this example. is preferably attached by inserting it into projection 24b.
The length of the tubular sleeve inserted inside the protrusion 24b is preferably 0-20 mm. Further, the length of the tubular sleeve 26 inserted inside the protruding portion 24b is preferably 10 to 50% of the total length of the tubular sleeve 26. As shown in FIG.
If the length of the tubular sleeve 26 inserted inside the protrusion 24b is within this range, workability is improved. In addition, the bonding area between the projecting portion 24b and the tubular sleeve 26 is widened, and the strength can be improved.

A stepped portion 27 is formed on the outer surface of the tubular sleeve 26 such that a portion of the tubular sleeve 26 that is not inserted into the projecting portion 24b protrudes from a portion that is inserted into the projecting portion 24b. The height of the step projecting outward from the insertion portion of the tubular sleeve is preferably 0.5 mm or more, more preferably 1 mm or more, from the outer wall of the insertion portion of the tubular sleeve. On the other hand, it is usually 5 mm or less, more preferably 3 mm or less. This allows the length of insertion of the tubular sleeve to be determined. By forming such a step 27, the length of the portion of the tubular sleeve 26 inserted into the projection 24b can be adjusted in a state where the tubular sleeve 26 is attached to the projection 24b.

The length L of the portion of the tubular sleeve 26 that is inserted into the protrusion 24b is preferably 5-30 mm, more preferably 10-20 mm. If the length L is equal to or greater than the lower limit of the above range, the connection strength between the projecting portion 24b and the tubular sleeve 26 can be easily increased. If the length L is equal to or less than the upper limit of the above range, molding of the tubular sleeve is easy.

Projection 24b and tubular sleeve 26 may form a mating structure. By forming a fitting structure, the connection strength between the protrusion 24b and the tubular sleeve 26 is increased.

In this embodiment, the tip of the tubular sleeve 26 connected to the protrusion 24b, which is opposite to the water collecting portion 20e, protrudes further to the side opposite to the water collecting portion 20e than the tip of the protrusion 24b. Thus, the tubular sleeve 26 can be attached to the protrusion 24b to increase the height of that portion. As a result, when the potting material 30 is injected around the protrusion 24b and the tubular sleeve 26, the injection amount of the potting material 30 can be increased compared to when the tubular sleeve 26 is not attached. The potting material 30 does not enter the water collection portion of the first water collection pipe 12 before the tubular strut 16 is connected. Therefore, the number of injections and curing of the potting material 30 for sealing the insertion portion 28 in a watertight manner can be reduced.

The height D of the projection 29 when the tubular support 16 is inserted into the projection 29 having the tubular sleeve 26 attached to the projection 24b is the height D from the lower end of the tubular support 16 to the tip of the tubular sleeve 26. . The height D of the protrusion 29 is 40% or more of the height E of the lowest portion of the peripheral wall portion 24c.
The height D of the protrusion 29 is, for example, preferably 20-60 mm, more preferably 30-50 mm. If the height D of the protrusion 29 is 40% or more of the height E of the lowest portion of the peripheral wall portion 24c, the number of injections and curing of the potting material 30 can be reduced, and the protrusion 24b and the tubular strut 16 can be separated from each other. It is easy to increase the connection strength. From the viewpoint of ease of molding of the water collection pipe and tubular sleeve, which are molded products, it is preferable that the height D is not too high.

The material for the tubular sleeve is preferably one that has excellent mechanical strength and durability. Examples thereof include metals such as SUS304 and SUS316L, polycarbonate, polysulfone, polyolefin, PVC (polyvinyl chloride), acrylic resin, ABS resin, and modified PPE (polyphenylene ether). The tubular sleeve may be made of one material or two or more materials.

A potting material 30 is filled around the first end portion 17a of the tubular support 16 inside the peripheral wall portion 24c of the first end portion 13a of the first water collecting pipe 12 . As a result, the first water collecting pipe 12 and the tubular support 16 are preferably fixed in a watertight manner. The insertion portion 28 in which the protrusion 24b and the tubular sleeve 26 are inserted into the first end portion 17a of the tubular strut 16 is watertightly sealed with a potting material 30 so that the inside and the outside are separated. It is preferably fixed.
When the water collecting pipe 12 and the tubular support 16 are fixed in a watertight manner, the bonding strength between the water collecting pipe and the tubular support is improved, and the structural strength of the hollow fiber membrane element is increased. In addition, the life of the hollow fiber membrane element during backwashing is improved.
As a method of sealing watertightly, potting, placement of sealing materials such as O-rings, etc. are preferable.

At the insertion portion 28 , it is preferable that the gap between the tubular strut 16 and the tubular sleeve 26 is watertightly sealed with a potting material 30 . That is, it is preferable that not only the outside of the insertion portion 28 is sealed with the potting material 30 , but also the gap between the tubular strut 16 and the tubular sleeve 26 in the insertion portion 28 is filled with the potting material 30 . This improves the adhesion between the tubular support 16 and the potting material 30 at the insertion portion 28, and improves the mechanical strength of the hollow fiber membrane element 1.
Similarly, the gap between the tubular strut 16 and the protrusion 24b in the insertion portion 28 is preferably sealed with the potting material 30 in a watertight manner.

The length of the potting agent in the gap between the tubular strut and the projection is preferably 60% or more, more preferably 80% or more of the height of the projection. The length of the potting material represents the length of the bonded portion between the tubular support and the projection. By setting the length of the potting material within this range, the structural strength of the bonding between the water collection pipe and the tubular support is improved, and the structural strength of the hollow fiber membrane element is increased. In addition, the life of the hollow fiber membrane element during backwashing is improved.

The potting material 30 for fixing the first water collection pipe 12 and the second water collection pipe 14 to the tubular support 16 (18) may be, for example, resin such as hard resin or soft resin, or water such as Portland cement or mixed cement. Hard cement can be used. As the potting material 30, a hard resin having a Shore A hardness of 80 or more as measured according to JIS C 2105:2006 is preferable because it has a higher adhesive strength with the tubular support and excellent watertightness. When the potting material 30 is made of a hard resin, the Shore A hardness is preferably 99 or less because the potting material 30 is hard to break. A soft resin having a Shore A hardness of less than 80 may be used as the potting material 30 .

Examples of hard resins include epoxy resins, unsaturated polyester resins, polyurethane resins, silicone fillers, and various hot-melt resins.
Examples of the soft resin include polyurethane resins, silicone-based fillers, and various hot-melt resins.

It is preferable that the protrusion 29 tapers toward the tip. This makes it easier to insert the tubular strut 16 . Moreover, it is easy to prevent the potting material 30 injected around the protrusion 29 from being stripped off when the tubular support 16 is inserted.

Moreover, it is preferable that the protrusion 24b tapers toward the tip. This makes it easier to insert the tubular strut 16 . Moreover, it is easy to prevent the potting material 30 injected around the protruding portion 24b from being peeled off when the tubular strut 16 is inserted. In addition, demolding is facilitated when the first water collecting pipe 12 is manufactured by injection molding. For the same reason, the portion of the tubular sleeve 26 that is not inserted into the protruding portion 24b is preferably tapered toward the distal end.

The angle at which the protrusion, the protrusion, and the tubular sleeve taper toward the tip is preferably 1° or more, more preferably 2° or more. This angle range makes it easy to insert the tubular strut, and when it is completely inserted, a portion of the tubular strut can be fitted into the fitting structure, so that the fixing position of the tubular strut can be determined.
The angle at which the protrusion, the protrusion, and the tubular sleeve taper toward the tip is preferably 60° or less, more preferably 45° or less. When the angle is within this range, the height of the tubular sleeve can be ensured. Also, the friction between the tubular strut and the tubular sleeve is greater than the force tending to move the tubular strut from the portion where the tubular strut is in contact with the tubular sleeve. This allows smooth insertion of the tubular strut into the tubular sleeve. Further, when the angle is equal to or less than the upper limit, the width of the outlet of the water collecting pipe can be sufficiently secured, the pressure loss when water passes can be reduced, and the water can easily pass. Also, the angle at which the tubular sleeve tapers toward its distal end may not be constant. If the angle is not constant, the angle is the average angle.
Here, the angle at which the projection, the projection, and the tubular sleeve taper toward the tip is defined as follows: The angles of the projections, projections, and circumference of the tubular sleeve are shown with reference to a direction parallel to the central longitudinal axis of the hole.

If the thickness of the base of the projection on the water collecting pipe side is greater than or equal to the inner diameter of the tubular support, the projection and the inner side of the tubular support are in close contact. This is preferable in that the strength of the hollow fiber membrane element is improved.
If the thickness of the base of the projection on the water collecting pipe side is smaller than the inner diameter of the tubular support, the projection can be easily inserted into the tubular support, which is preferable from the viewpoint of workability. In addition, the end surface of the tubular support abuts against the water collection pipe, and the height from the base of the tubular support to the water collection pipe on the opposite side is constant. Therefore, it is preferable in that it is easy to secure assembly accuracy of the hollow fiber membrane element.

The outer surface of the first end 17a of the tubular strut 16 is preferably blasted. In the present invention, the outer surfaces of the ends of tubular struts 16 and tubular struts 18 are preferably blasted. The outer surfaces of the ends of the tubular struts 16 and 18 are in contact with potting material that seals and secures the inserts with the projections and tubular sleeves inserted therein in a water-tight manner. By blasting the outer surface of the ends of the tubular struts 16 (18), the adhesion between the tubular struts and the potting material is improved, and the strength of the hollow fiber membrane element is improved.
The area of the tubular column to be blasted is preferably 70% or more, more preferably 90% or more, of the area of the tubular column fixed with the potting material. The area of the tubular strut to be blasted is usually 120% or less, more preferably 100% or less. Thereby, the adhesive strength improvement effect can fully be expressed.
The blasting method is not particularly limited.

Also, in this example, blocks 32, 32, 32 are provided on both longitudinal sides of the first end 17a of the tubular strut 16 into which the projection 24b and the tubular sleeve 26 are inserted inside the peripheral wall 24c of the first water collecting pipe 12. 34 are provided.
The blocks 32 and 34 are provided in a state of being buried in the potting material 30 filled inside the peripheral wall portion 24c.
In the present invention, as described above, it is preferable that the periphery of the projection is surrounded by the peripheral wall portion at both end portions of the first water collecting pipe and the second water collecting pipe. Further, it is preferred that blocks are provided on the inside of the peripheral wall on both longitudinal sides of the ends of the tubular struts 16 (18) into which the projections and tubular sleeves are inserted. As a result, even when a load is applied to the tubular support, it is possible to prevent the tubular support from collapsing and being damaged.

The form of the block is not particularly limited, and examples thereof include a cylindrical body and a columnar body.
The material of the block is not particularly limited, and examples thereof include the same materials as those of the water collecting pipe.
A rectangular parallelepiped part of the water collecting pipe may be integrally molded so as to have the same function as the block.

In the hollow fiber membrane element 1, the protective layer 33 covers the hardened potting material filled inside the peripheral wall surrounding the protrusions at the first end 13a and the second end 13b of the first water collecting pipe 12. may be set as follows. The protective layer 33 may be provided so as to cover the potting portion for fixing the first open end of the hollow fiber membrane sheet.
The protective layer 33 is a layer made of soft resin. Soft resins used for the protective layer 33 include, for example, the same soft resins as the potting material 30 . By providing the flexible protective layer 33 made of a soft resin, the hollow fiber membranes 11 are prevented from being damaged at the boundary between the part of the hollow fiber membrane sheet 10 that is embedded in the resin and the part that is not embedded in the resin. Cheap. Moreover, by providing the flexible protective layer 33 made of a soft resin, it is easy to suppress cracks in the potting material that seals the periphery of the tubular strut 16 (18).

A first closure that blocks the flow of treated water that has flowed into the first water collection pipe 12 into the water collection portion 20e of the first water collection pipe 12 through the first open end portion 10a of the hollow fiber membrane sheet 10 and into the tubular support 16. A portion 36 is preferably provided.
A second closure that blocks the flow of the treated water that has flowed into the second water collecting pipe 14 into the water collecting portion 20f of the second water collecting pipe 14 through the second open end portion 10b of the hollow fiber membrane sheet 10 to the tubular support 18. A portion 38 is preferably provided.
By the first closing part 36 and the second closing part 38, the portion of the hollow fiber membrane sheet 10 used for processing can be suppressed from being biased, and the hollow fiber membrane sheet 10 can be efficiently used for processing as a whole. can do.

For example, in this example, the first closing portion 36 is provided on the first end portion 13a side of the hollow fiber membrane sheet 10 in the longitudinal direction of the first water collecting pipe 12 with respect to the first opening end portion 10a. A second closing portion 38 is provided on the second end portion 15b side of the hollow fiber membrane sheet 10 in the longitudinal direction of the second water collecting pipe 14 relative to the second opening end portion 10b. At the end faces of the first end portion 15a and the second end portion 15b of the second water collecting pipe 14, outlets 40a and 40b for taking out treated water are formed.
Either one of the first closing portion and the second closing portion may be provided, or both may be provided.

The first closing portion 36 is a portion that blocks the flow of the treated water that has flowed into the water collecting portion 20 e through the first open end 10 a of the hollow fiber membrane sheet 10 to the tubular support 16 . The second closing portion 38 is a portion that blocks the flow of the treated water that has flowed into the water collecting portion 20 f through the second open end 10 b of the hollow fiber membrane sheet 10 to the tubular support 18 .
The form of the first closing part 36 and the second closing part 38 is not particularly limited as long as it can block the flow of treated water.

In such a mode, as shown in FIG. 2, treated water is collected in the water collection portion 20e of the first water collection pipe 12 from the lower portion of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10. As shown in FIG. Treated water is sent through the tubular strut 18 to the second end 15b of the upper second collection pipe 14 . The treated water is taken out from the take-out port 40b. Also, the treated water is collected from the upper portion of each hollow fiber membrane 11 of the hollow fiber membrane sheet material 10 to the water collecting portion 20 f of the second water collecting pipe 14 . Treated water is sent to the first end 15 a of the second water collection pipe 14 . The treated water is taken out from the take-out port 40a. As a result, the hollow fiber membrane sheet 10 can be efficiently used for processing as a whole.

The hollow fiber membrane element of the present invention is not limited to the hollow fiber membrane element 1 described above.
For example, the distal portion of the projection may be inserted into the tubular sleeve so that the tubular sleeve is attached to the projection. Also, the number and positions of the outlets are not limited to the numbers and positions described above, and can be set as appropriate.
The hollow fiber membrane element may be used in a state in which each hollow fiber membrane of the hollow fiber membrane sheet is arranged such that the length direction thereof is horizontal.
In the present invention, existing members other than the tubular sleeve, such as the water collection tube, the tubular support, and the hollow fiber membrane, can be used. For example, a tubular sleeve may be manufactured to match the protrusion of a water collecting pipe having a tubular protrusion at the end for connection with a tubular support, and these sleeves may be combined to form the hollow fiber membrane element of the present invention.

Another aspect of the projections 29 arranged at the first end portion 13a of the first water collecting pipe 12 in the hollow fiber membrane element of the present invention is, as shown in FIG. First, it consists of the protrusion 24b. The protrusions disposed on the second end 13b of the first water collection pipe 12 and the first and second ends 15a and 15b of the second water collection pipe 14 can be similar.

Further, in the hollow fiber membrane element of the present invention, still another aspect of the projections 29 arranged at the first end portion 13a of the first water collecting pipe 12 is, as shown in FIG. It does not include, but consists of a tubular sleeve 26 . The protrusions disposed on the second end 13b of the first water collection pipe 12 and the first and second ends 15a and 15b of the second water collection pipe 14 can be similar.

[Method for producing hollow fiber membrane element]
The method for producing a hollow fiber membrane element of the present invention is a method for producing the above-described hollow fiber membrane element of the present invention. As an example of the method for producing the hollow fiber membrane element of the present invention, the method for producing the hollow fiber membrane element 1 will be described below.

A method for producing the hollow fiber membrane element 1 includes a method having the following steps (a) to (c).
Step (a): Connect the tubular struts 16 and 18 to the projections of the first end 13a and the second end 13b of the first water collecting pipe 12, respectively.
Step (b): Connect the tubular struts 16 and 18 to the projections of the first end 15a and the second end 15b of the second water collecting pipe 14, respectively.
Step (c): The first open end 10a of the hollow fiber membrane sheet 10 is inserted into the first water collecting pipe 12 and fixed with a potting material, and the second hollow fiber membrane sheet 10 is attached to the second water collecting pipe 14. The open end 10b is inserted and fixed with a potting material.

(Step (a))
A projection 29 is provided by inserting a portion of a tubular sleeve 26 into a projection 24b provided on the first end 13a of the first water collecting pipe 12 and attached thereto. Next, the side of the first water collecting pipe 12 on which the projections 29 are provided is turned up, and the potting material 30 is injected around the projections 29 inside the peripheral wall portion 24c. The injection amount of the potting material 30 is adjusted so that the surface of the potting material 30 is as close to the tip of the protrusion 29 as possible within a range in which the potting material 30 does not enter through the opening at the tip of the protrusion 29 .

The first end 17a of the tubular strut 16 is then inserted into the first end 13a of the first collecting pipe 12 such that the projection 29 is inserted into the first end 17a of the tubular strut 16 . A potting material 30 is injected. Tubular struts 16 are then inserted into the projections 29 before the potting material 30 is cured. As a result, the potting material 30 also enters between the protrusion 29 and the tubular strut 16 in the insertion portion 28 . As a result, the gap between the protrusion 29 and the tubular strut 16 is filled with the potting material 30 to be watertightly sealed.

Blocks 32 and 34 are installed on both sides of the tubular support 16 in the longitudinal direction of the first water collection pipe 12 within the peripheral wall portion 24c. After that, the potting material 30 is cured. The first end 13a of the first water collecting pipe 12 and the first end 17a of the tubular support 16 are connected. The insertion portion 28 having the protrusion 29 inserted into the first end portion 17a of the tubular strut 16 is fixed with a potting material 30 in a water-tight manner.

At the second end portion 13b of the first water collecting pipe 12, similarly to the first end portion 13a, the potting material is injected around the projection. Insert the first end 19a of the tubular strut 18, place the block and allow the potting material to cure. The insertion portion in which the projection is inserted into the first end portion 19a of the tubular strut 18 is fixed in a state of being watertightly sealed with a potting material.

(Step (b))
At each of the first end portion 15a and the second end portion 15b of the second water collection pipe 14, potting material is injected around the projections, as in the case of the first water collection pipe 12. As shown in FIG. Next, while the tubular struts 16 and 18 connected to the first water collection pipe 12 are turned upside down, the second end 17b of the tubular strut 16 is inserted into the first end 15a of the second water collection pipe 14 from above. . Further, the second end 19b of the tubular support 18 is inserted into the second end 15b of the second water collecting pipe 14 from above. After that, the block is placed and the potting material is cured. The second end 17b of the tubular strut 16 and the second end 19b of the tubular strut 18 are connected to the first end 15a and the second end 15b of the second water collecting pipe 14 . At this time, the insertion portion in which the projection is inserted into the tubular strut is fixed in a state of being water-tightly sealed with a potting material.

(Step (c))
The hollow fiber membrane sheet 10 can be formed, for example, by bundling a plurality of hollow fiber membranes 11 into a sheet and, if necessary, tying both of them near the open ends with a belt-shaped tying member.
With the first water collecting pipe 12 facing downward, the first opening end 10a of the hollow fiber membrane sheet 10 is inserted into the slit-like opening 20d of the first water collecting pipe 12, and the end face of each hollow fiber membrane 11 is opened. Fix with potting material. Next, the second water collection pipe 14 is turned upside down, and the second opening end 10b of the hollow fiber membrane sheet 10 is inserted into the slit-shaped opening of the second water collection pipe 14. It is fixed with a potting material while the end face of is open.

As described above, in the present invention, tubular sleeves are attached to the tubular projections provided at both ends of the water collection pipe and inserted into the ends of the tubular struts, and the inserted portions are watertightly sealed with potting material. The end of the collection tube is connected to the end of the tubular strut by sealing and securing. Injection of potting material to watertightly seal and fix the insertion part where the protrusion is inserted into the end of the tubular strut by setting the height of the protrusion to 40% or more of the height of the lowest part of the peripheral wall. And the number of times of curing can be reduced. Therefore, the work is simpler, the production efficiency is higher, the curing time is shorter, and the productivity is excellent.
In addition, compared to the case where the height of the protrusion is less than 40% of the height of the lowest part of the peripheral wall, the bonding area between the protrusion and the tubular support by the potting material can be increased, so the connection strength between them can be increased. can be higher.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited by the following description.
Examples 1 to 3 correspond to examples, and example 4 corresponds to a comparative example.

[Adhesion strength]
The adhesive strength (withstanding load) between the protrusions and the tubular sleeve at the insertion portion of each example and the ends of the tubular struts was measured by a pull-up fracture test of the hollow fiber membrane element.
The withdrawal test was performed by the following method.
The hollow fiber membrane element is erected with the tubular strut 16 on the bottom and the tubular strut 18 on the top so that the tubular strut is horizontal and the water collection pipe is vertical, and the tubular strut 16 is placed at the center in the longitudinal direction so that the tubular strut 16 is not lifted. The part was fixed on a horizontal plane. In addition, the central portion in the longitudinal direction of the upper tubular support 18 and a hoist crane suspended from the ceiling were connected via a spring balance. An upward load was applied to the hollow fiber membrane element by a hoist crane. While increasing the load in increments of 10 kg up to a maximum load of 100 kg, the adhesive portion between the tubular support 16 and the potting material was visually observed, and the load at which breakage occurred was recorded as the adhesive strength.

[Example 1]
ABS resin was used to manufacture the first water collecting pipe 12 and the tubular sleeve 26 illustrated in FIGS. 4 and 8 by injection molding. At the first end 13a of the first collecting pipe 12, a projection 29 is provided by inserting and attaching a portion of a tubular sleeve 26 to the projection 24b. The height of the protrusion 29 was 87.5% of the height of the lowest portion of the peripheral wall portion 24c. A specified amount of urethane resin having a Shore A hardness of 90 was injected as a potting material 30 around the projection 29 while taking care not to enter the potting material into the water collecting portion. The first end 17a of the SUS tubular support 16 was inserted into the protrusion 29 of the first end 13a of the first water collecting pipe 12, and the protrusion 29 was inserted into the first end 17a of the tubular support 16. Blocks 32 and 34 made of ABS resin were installed on both longitudinal sides of the first end portion 17a of the tubular support 16 inside the peripheral wall portion 24c of the first water collecting pipe 12 so as to be embedded in the potting material 30, respectively. The potting material 30 injected up to the height of the end of the tubular sleeve is hardened to water-tightly seal the insertion portion 28 where the projection 29 is inserted into the first end 17a of the tubular support 16 with the potting material 30. , and the tubular strut 16 and the first water collecting pipe 12 were connected. The outer surface of the first end 17 a of the tubular strut 16 was blasted before being connected to the first water collecting pipe 12 .
The number of times of injection and curing of the urethane resin was one, and a hollow fiber membrane element with high work efficiency and excellent productivity was obtained.
The adhesion strength was measured by a pull-up fracture test of the hollow fiber membrane element. The load applied to the hoist crane was lifted up to 100 kg, but no breakage was observed. The adhesive strength between the urethane resin and the tubular strut 16 at the insertion portion 28 was 100 kg or more.

[Example 2]
The tubular support 16 and the first water collecting pipe 12 are connected in the same manner as in Example 1, with the protrusions 29 communicating, except that the portion of the outer surface of the tubular support 16 that contacts the potting material 30 is not blasted. and cured the urethane resin.
The urethane resin was injected once and cured once.
The adhesion strength was measured by a pull-up fracture test of the hollow fiber membrane element. The load applied to the hoist crane was lifted up to 100 kg, but no breakage was observed. The adhesive strength between the protrusion 24b in the insertion portion 28 and the tubular sleeve 26 and the tubular strut 16 was 100 kg or more.

[Example 3]
Using ABS resin, the first water collection pipe 12 illustrated in FIGS. 4 and 8 was manufactured by injection molding. The height of the projecting portion 24b was 37.5% of the height of the lowest portion of the peripheral wall portion 24c. A specified amount of urethane resin having a Shore A hardness of 65 was injected around the first end portion 13a of the first water collecting pipe 12 so as not to enter the water collecting portion 20e. After the urethane resin is injected, the first end 17a of the SUS tubular support 16 is inserted into the projection 24b of the first end 13a of the first water collecting pipe 12, and the projection 24b is inserted into the first end of the tubular support 16. inserted into 17a. Blocks 32 and 34 made of ABS resin were installed on both longitudinal sides of the first end portion 17a of the tubular support 16 inside the peripheral wall portion 24c of the first water collecting pipe 12, respectively. After setting the block, a specified amount of potting material 30 having a Shore A hardness of 90 was injected so that the block was buried in the potting material. The potting material 30 injected up to the height of the protrusion is hardened, and the insertion portion 28 where the protrusion 24b is inserted into the first end 17a of the tubular strut 16 is fixed with the potting material 30 in a watertight manner. Then, the tubular strut 16 and the first water collecting pipe 12 were connected. The outer surface of the first end 17 a of the tubular strut 16 was blasted before being connected to the first water collecting pipe 12 .
The adhesion strength was measured by a pull-up fracture test of the hollow fiber membrane element. Failure was observed at a load of 78 kg applied to the hoist crane. The bonding strength between the protrusion 24b and the tubular sleeve 26 in the insertion portion 28 and the tubular strut 16 was 78 kg.
Since no tubular sleeve was used, the urethane resin had to be injected and cured twice, which was labor intensive and the production efficiency was poor.

[Example 4]
Using ABS resin, the first water collection pipe 12 illustrated in FIGS. 4 and 5 was manufactured by injection molding. The height of the projecting portion 24b was 37.5% of the height of the lowest portion of the peripheral wall portion 24c. A specified amount of urethane resin having a Shore A hardness of 65 was injected around the first end portion 13a of the first water collecting pipe 12 so as not to enter the water collecting portion 20e. After the urethane resin is injected, the first end 17a of the SUS tubular support 16 is inserted into the projection 24b of the first end 13a of the first water collecting pipe 12, and the projection 24b is inserted into the first end of the tubular support 16. inserted into 17a. Blocks 32 and 34 made of ABS resin were installed on both longitudinal sides of the first end portion 17a of the tubular support 16 inside the peripheral wall portion 24c of the first water collecting pipe 12, respectively. After the blocks were installed, a specified amount of potting material 30 having a Shore A hardness of 90 was injected so that the blocks were embedded in the resin. The potting material 30 is cured to fix the insertion portion where the protrusion 24b is inserted into the first end 17a of the tubular strut 16 in a water-tight manner with the potting material 30, thereby joining the tubular strut 16 and the first assembly. The water pipe 12 was connected. The outer surface of the first end 17a of the tubular strut 16 was not blasted.
The urethane resin had to be injected and cured twice, which was labor intensive and inefficient in production.
When the adhesive strength was measured by a pull-up fracture test of the hollow fiber membrane element, the adhesive strength between the protrusion 24b and the tubular strut 16 at the insertion portion was 51 kg.

Reference Signs List 1 Hollow fiber membrane element 10 Hollow fiber membrane sheet 10a First opening end 10b Second opening end 11 Hollow fiber membrane 12 First water collecting pipe 13a First end Part 13b... Second end 14... Second water collecting pipe 15a... First end 15b... Second end 16, 18... Tubular strut 17a... First end 17b... Second end , 19a... First end 19b... Second end 20a, 20b... Side wall part 20c... Bottom part 20d... Opening part 20e, 20f... Water collecting part 22a... Potting part 24a... Cylindrical part, 24b... Projection 24c... Peripheral wall 24d... Opening 25... Lid member 26... Tubular sleeve 27... Step 28... Insertion part 29... Projection 30... Potting material 32, 34... Block 33... Protective layer, 36...first closing part, 38...second closing part, 40a, 40b...outlet.

Claims (14)

a plurality of hollow fiber membranes;
a first water collection pipe and a second water collection pipe respectively provided on the first opening end side and the second opening end side in the length direction of the hollow fiber membrane;
a tubular support having both ends connected to the first water collection pipe and the second water collection pipe;
with
The first open end and the second open end of the hollow fiber membrane are inserted into the first water collection pipe and the second water collection pipe, respectively, with the end faces of the hollow fiber membranes being open,
At least one of the first water collection pipe, the second water collection pipe, and the tubular support is formed with at least one outlet for taking out treated water,
The first water collecting pipe and the second water collecting pipe are provided with tubular projections for connecting with the tubular struts communicating with the water collecting portions inside the first water collecting pipe and the second water collecting pipe. ,
A peripheral wall portion surrounding the projection is provided,
the protrusion is located within the end of the tubular strut;
The height of the projection is 40% or more of the height of the lowest portion of the peripheral wall,
The inside of the tubular support and the water collecting portions inside the first water collecting pipe and the second water collecting pipe are in communication via the inside of the projection,
Hollow fiber membrane element. 2. The hollow fiber membrane element according to claim 1, wherein said tubular support and said first and second water collection pipes are fixed in a watertight manner. 3. The hollow fiber membrane element according to claim 1, wherein a gap between said tubular strut and said projection is watertightly sealed. Claims 1 to 3, wherein the protrusion comprises a tubular protrusion communicating with the water collecting portion inside the first water collecting pipe and the second water collecting pipe, and a tubular sleeve connected to the protrusion. 4. The hollow fiber membrane element according to any one of 3. 5. The hollow fiber membrane element according to claim 4, wherein a portion of the tubular sleeve on the protruding portion side is inserted inside the protruding portion. 6. The hollow fiber membrane element according to claim 5, wherein a step is formed on the outer surface of the tubular sleeve such that a portion of the tubular sleeve that is not inserted into the protrusion protrudes from a portion that is inserted into the protrusion. The hollow fiber membrane element according to claim 5 or 6, wherein the protrusion and the tubular sleeve form a fitting structure. The hollow fiber membrane element according to any one of claims 4 to 7, wherein the protrusions are tapered toward their tips. The hollow fiber membrane element according to any one of claims 1 to 3, wherein the projection is formed integrally with the first water collecting pipe and the second water collecting pipe. The hollow fiber membrane according to any one of claims 1 to 3, wherein the projection is composed of a tubular sleeve connected to openings provided in the first water collecting pipe and the second water collecting pipe. element. The hollow fiber membrane element according to any one of claims 1 to 10, wherein the outer surface of the ends of the tubular struts is blasted. The first water collecting pipe is provided with a first closing portion that blocks the flow of treated water that has flowed into the water collecting portion of the first water collecting pipe through the first open end of the hollow fiber membrane to the tubular support. and/or a second closure for blocking flow of treated water flowing through said second open end of said hollow fiber membrane into said catchment portion of said second catchment pipe to said tubular strut. 12. The hollow fiber membrane element according to any one of claims 1 to 11, provided with a portion. A method for producing the hollow fiber membrane element according to claim 1,
A method for manufacturing a hollow fiber membrane element, wherein the protrusions are inserted into the ends of the tubular struts. 14. The method for producing a hollow fiber membrane element according to claim 13 , wherein the tubular support and the first and second water collection tubes are fixed in a watertight manner.

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