CN216964173U

CN216964173U - Hollow fiber membrane element, hollow fiber membrane module, and water treatment device

Info

Publication number: CN216964173U
Application number: CN202122287963.2U
Authority: CN
Inventors: 糸山靖幸
Original assignee: Mitsubishi Chemical Corp
Current assignee: Mitsubishi Chemical Corp
Priority date: 2020-09-23
Filing date: 2021-09-22
Publication date: 2022-07-15
Anticipated expiration: 2031-09-22
Also published as: CN114247292A

Abstract

The utility model provides a hollow fiber membrane element with excellent pressure resistance, a hollow fiber membrane element and a water treatment device. The hollow fiber membrane element has: the hollow fiber membrane comprises a hollow fiber membrane, a water collecting pipe and a take-out port for taking out treated water from the water collecting pipe, wherein the hollow fiber membrane and the water collecting pipe are fixed through a pouring part, a water collecting path with the pouring part and the water collecting pipe as wall surfaces is arranged in the water collecting pipe, the end part of the hollow fiber membrane is communicated with the water collecting pipe, and the cross section area of the cross section of any water collecting path, which is perpendicular to the long edge direction, of the water collecting pipe is 100-350 mm²。

Description

Hollow fiber membrane element, hollow fiber membrane module, and water treatment device

Technical Field

The present invention relates to a hollow fiber membrane element, a hollow fiber membrane module, a water treatment apparatus, and a water treatment method.

Background

Hollow fiber membrane elements are widely used for the production of sterile water, potable water, highly pure water, and the like. As a hollow fiber membrane element, for example, a hollow fiber membrane element is known in which water collecting pipes are provided at both ends in the longitudinal direction of the hollow fiber membrane and tubular struts connected in a state of being communicated with the water collecting pipes are provided (patent document 1).

In the hollow fiber membrane element as in patent document 1, tubular projections communicating with the water collecting sections are provided at both end portions of the water collecting pipe, and the projections are fitted and connected to the end portions of the tubular struts. In the production of the hollow fiber membrane element, for example, resin is injected around the protrusion of the header pipe with the protrusion side of the header pipe facing upward, the end of the tubular strut is inserted into the end of the header pipe so that the protrusion is inserted into the end of the tubular strut, and then the resin is cured. By inserting the tubular post into the end of the water collecting pipe with the resin injected around the protrusion, the gap between the protrusion inserted into the end of the tubular post and the tubular post is also filled with the resin, and thus, a hollow fiber membrane element having excellent water tightness at the connection portion between the water collecting pipe and the tubular post can be obtained.

Documents of the prior art

Patent literature

Patent document 1: chinese utility model specification No. 202006088

Among hollow fiber membrane elements, a hollow fiber membrane element having a small pressure loss is preferable in that the energy required for operation is small.

Therefore, in a hollow fiber membrane element of a type in which water is collected from an end of the hollow fiber membrane via a water collection pipe, the hollow fiber membrane element having a large cross-sectional area of a water channel inside the water collection pipe is preferable because the pressure loss is small.

A hollow fiber membrane element generally uses a plurality of hollow fiber membrane elements as a hollow fiber membrane module. When the thickness of the hollow fiber membrane element is small, the membrane cleaning performance is easily improved, and the amount of treated water per unit volume is easily increased. Therefore, in the case where there is a limitation in the place of installation, a thinner hollow fiber membrane element may be used.

In the case of using a thin hollow fiber membrane element, in order not to increase the pressure loss, the maximum length (height) between the bottom of the header pipe and the portion of the casting part that is farthest from the bottom and is in contact with the wall of the header pipe is extended, thereby increasing the cross-sectional area of the water channel inside the header pipe.

As a method for cleaning a hollow fiber membrane element, for example, a back washing method is known in which washing water is made to flow from a water collecting pipe side to the hollow fiber membrane in order to remove dirt.

When the height of the water channel inside the water collecting pipe of the thin hollow fiber membrane element is increased, it is found that water leakage occurs due to breakage when reverse cleaning under high pressure (for example, 1MPa or more) is studied, and there is room for improvement in pressure resistance.

SUMMERY OF THE UTILITY MODEL

The utility model provides a hollow fiber membrane element and a hollow fiber membrane module with excellent pressure resistance.

Means for solving the problems

The present invention has the following structure.

[1] A hollow fiber membrane element having: a hollow fiber membrane, a water collecting pipe, and a take-out port for taking out treated water from the water collecting pipe,

the hollow fiber membrane and the water collecting pipe are fixed through a pouring part,

a water collecting passage having the pouring section and the water collecting pipe as wall surfaces is provided inside the water collecting pipe,

the end part of the hollow fiber membrane is communicated with the water collecting pipe,

the sectional area of any water collecting path section of the water collecting pipe vertical to the long edge direction is 100-350 mm²。

[2] The hollow fiber membrane element according to [1], wherein a length of the cross section of the water collection channel in a longitudinal direction of the hollow fiber membrane is 20mm or less.

[3] The hollow fiber membrane element according to [1] or [2], which comprises at least one of a deformation suppressing member in contact with a wall of the water collecting duct and a deformation suppressing member integrated with the water collecting duct.

[4] The hollow fiber membrane element according to [3], wherein the deformation suppressing member is a rib.

[5] In the hollow fiber membrane element according to any one of [1] to [4], the water collection pipe has a step, and the step is joined to a lower portion of the pouring section.

[6] The hollow fiber membrane element according to [5], wherein the step is 0.5mm or more.

[7] In the hollow fiber membrane element according to any one of [1] to [6],

the water collecting pipe is composed of a first water collecting pipe and a second water collecting pipe,

the second header pipe is located on the opposite side of the first header pipe in the longitudinal direction of the hollow fiber membranes, and the first header pipe and the second header pipe are connected by a strut.

[8] In the hollow fiber membrane element according to [7], the water passage inside the column communicates with the first water collecting passage of the first header pipe and the second water collecting passage of the second header pipe, respectively.

[9] In the hollow fiber membrane element according to [8], a relationship of 0.5 x a ≦ b is satisfied where b is a cross-sectional area of an arbitrary surface of the water collecting channel of the water collecting header perpendicular to the longitudinal direction and a is a cross-sectional area of an arbitrary surface of the water passage of the support column perpendicular to the longitudinal direction.

[10] The hollow fiber membrane element according to [9], which satisfies the following formula (1) and formula (2):

a/b₁≥0.9···(1)

a/b₂≥0.9···(2)

wherein a is an arbitrary cross-sectional area of the water passage of the strut,

b₁is a section of the first water collecting channel of the first water collecting pipe on any surface perpendicular to the long side direction The area of the first electrode is larger than the area of the second electrode,

b₂the cross-sectional area of an arbitrary surface of the second water collecting channel of the second water collecting pipe perpendicular to the longitudinal direction.

[11] The hollow fiber membrane element according to [9] or [10], which satisfies the following formula (3) and formula (4):

0.5×a≤b₁···(3)

0.5×a≤b₂···(4)

b₁is the cross-sectional area of an arbitrary surface of the first water collecting channel of the first water collecting pipe perpendicular to the longitudinal direction,

[12] A hollow fiber membrane module comprising a plurality of hollow fiber membrane elements according to any one of [1] to [11 ].

[13] A water treatment apparatus comprising the hollow fiber membrane module according to [12] and an air diffuser disposed below the hollow fiber membrane module.

[14] A water treatment method using the water treatment apparatus as described in [13 ].

The present invention may have the following other configurations.

[A1] A hollow fiber membrane element having:

a hollow fiber membrane;

a water collecting pipe that collects the treated water recovered by the hollow fiber membrane; and

a take-out port that takes out the treated water from the water collecting pipe, wherein,

the water collecting pipe has a pillar extending in parallel with the hollow fiber membranes,

the pillars have water passages communicating with the water collecting passage inside,

the cross-sectional area of the water collection channel on the surface of the water collection pipe perpendicular to the long side direction is less than or equal to the cross-sectional area of the water passage.

[A2] In the hollow fiber membrane element according to [ a1], where b is a cross-sectional area of the water collection channel and a is a cross-sectional area of the water passage channel, the following relationship is satisfied,

0.5×a≤b。

[A3] in the hollow fiber membrane element according to [ a1] or [ a2], W represents a maximum length between wall surfaces of the water collection header that face each other with a space therebetween in a short-side direction of the water collection header,

h represents a maximum length in a longitudinal direction of the hollow fiber membrane perpendicular to a longitudinal direction of the water collecting pipe from a portion of the pouring section that is in contact with the wall surface and is farthest from a bottom surface of the water collecting channel to the bottom surface,

H≤1.2×W。

[A4] the hollow fiber membrane element according to any one of [ a1] to [ A3], wherein the water collection header includes: a first water collecting pipe which is provided on one side in the long-side direction of the hollow fiber membrane and has a first water collecting channel; and a second water collecting pipe provided on the other side in the longitudinal direction of the hollow fiber membrane and having a second water collecting passage,

The first water collecting pipe and the second water collecting pipe are connected through the support column, and the first water collecting path and the second water collecting path are communicated with the water passage.

[A5] In the hollow fiber membrane element according to any one of [ a1] to [ a4], a rib is disposed at a lower portion of the water collection pipe.

[A6] In the hollow fiber membrane element according to [ a5], the rib is arranged so as to extend over seven or more of the length of the water collection channel in the longitudinal direction.

[A7] A hollow fiber membrane element having:

a hollow fiber membrane;

a take-out port for taking out treated water from the water collecting pipe, wherein,

the end of the hollow fiber membrane communicates with the water collecting pipe, and

the cross-sectional area of the water collecting channel on the surface of the water collecting pipe perpendicular to the long edge direction is 100-350 mm²，

The length of the water collecting channel in the longitudinal direction of the hollow fiber membrane on the surface of the water collecting pipe perpendicular to the longitudinal direction is 20mm or less.

[A8] A hollow fiber membrane element having:

a hollow fiber membrane;

the cross section area of the water collecting pipe, which is perpendicular to the long edge direction, of the water collecting channel is 100-350 mm²，

The hollow fiber membrane element has a member that is connected to and/or integrated with the wall of the water collection pipe and suppresses deformation of the wall.

[A9] The hollow fiber membrane element according to [ A7] or [ A8], wherein the water collection header includes a first water collection header and a second water collection header,

[A10] In the hollow fiber membrane element according to [ a9], a water collection portion located inside the support column and the first water collection pipe communicates with a second water collection portion located inside the second water collection pipe.

[A11]In [ A10 ]]In the hollow fiber membrane element according to the above, a cross-sectional area a of a portion of the column through which the supplied water passes and a cross-sectional area b of a portion of the first water collecting pipe through which the supplied water passes₁Ratio of (a)/(b)₁And a sectional area a of a portion of the pillar through which the water passes and a sectional area b of a portion of the second water collecting pipe through which the water passes₂Ratio of (a)/(b)₂Satisfying formula (1) and formula (2) simultaneously:

a/b₁≥0.9···(1)

a/b₂≥0.9···(2)。

[A12] in the hollow fiber membrane element according to any one of [ a1] to [ a11], a surface roughness of a joint surface of the water collection header with the pouring section is ra6.3 to 25.

[A13] In the hollow fiber membrane element according to any one of [ a1] to [ a12], a joint surface of the water collection header with the potting portion has irregularities.

[A14] The hollow fiber membrane element according to any one of [ a1] to [ a13], wherein a step is provided at a lower portion of a joint surface of the water collection header pipe with the pouring section.

[A15] The hollow fiber membrane element according to [ A14], wherein the step is 0.5mm or more.

[A16] A hollow fiber membrane module comprising a plurality of hollow fiber membrane elements as defined in any one of [ A1] to [ A15 ].

Effect of the utility model

According to the present invention, a hollow fiber membrane element and a hollow fiber membrane module having excellent pressure resistance can be provided.

Drawings

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

Fig. 2 is a front view of the hollow fiber membrane element of fig. 1.

Fig. 3 is a sectional view a-a of the hollow fiber membrane element of fig. 2.

Fig. 3A is a modification of the hollow fiber membrane element of the present invention.

Fig. 3B is a modification of the hollow fiber membrane element of the present invention.

Fig. 3C is a modification of the hollow fiber membrane element of the present invention.

Fig. 3D is a modification of the hollow fiber membrane element of the present invention.

Fig. 3E is a modification of the hollow fiber membrane element of the present invention.

Fig. 3F is a modification of the hollow fiber membrane element of the present invention.

Fig. 3G is a modification of the hollow fiber membrane element of the present invention.

Fig. 3H is a modification of the hollow fiber membrane element of the present invention.

Fig. 4 is a B-B sectional view of the hollow fiber membrane element of fig. 1.

Fig. 5 is a C-C sectional view of the hollow fiber membrane element of fig. 4.

Fig. 6 is a modification of the hollow fiber membrane element of the present invention.

Description of the symbols

1 … hollow fiber membrane element, 10 … hollow fiber membrane sheet, … a first open end, 10b … second open end, 11 … hollow fiber membrane, 12 … first water collecting pipe (water collecting pipe), 13a … first end, 13b … second end, 14 … second water collecting pipe (water collecting pipe), 15a … first end, 15b … second end, 16 … first tubular strut (strut), 17a … first end, 17b … second end, 18 … second tubular strut (strut), 19a … first end, 19b … second end, 20a … side wall, 20b … side wall, 20c … bottom, 20d … opening, 20e … first water channel (water collecting channel), 20f … second water collecting channel (water collecting channel), 20g water channel step …, 21 … part, 21a … deformation suppressing part, 22a … hollow fiber membrane sheet part, 23a … pouring part, and 3a pouring part … shell, 23b … pouring part, 23c … interface, 24a … cylindrical part, 24b … protrusion part, 24c … peripheral wall part, 24d … opening, 25 … cover part, 26 … tubular sleeve, 28 … insertion part, 30 … resin, 32 … block, 33 … protective layer, 34 … block, 36 … first sealing part, 38 … second sealing part, 40a, 40b … outlet, 61 … water passage.

Detailed Description

When the range of numerical values is expressed using the range of "to", the numerical values described before and after the range of "to" are included as the lower limit value and the upper limit value.

In the present invention, "arbitrary" and "at least a part of" have the same meaning.

1. 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 of the drawings illustrated in the following description are examples, and the present invention is not limited thereto, and can be implemented by appropriately changing the dimensions and the like without changing the gist of the present invention.

1.1 Structure of hollow fiber Membrane element

As shown in fig. 1 and 2, a hollow fiber membrane element 1 of the present embodiment includes: a hollow fiber membrane 11, a water collecting pipe, and

outlets

40a and 40b for taking out treated water from the water collecting pipe.

In the hollow fiber membrane element 1 shown in fig. 1 and 2, the header pipe is composed of the first header pipe 12 having the first water collection channel 20e inside and the second header pipe 14 having the second water collection channel 20f inside. The first water collecting pipe 12 and the second water collecting pipe 14 are disposed on opposite sides in the longitudinal direction of the hollow fiber membranes 11 of the hollow fiber membrane sheet 10 in which the plurality of hollow fiber membranes 11 are bundled. The ends of the first and

second headers

12 and 14 are connected to each other by first and second

tubular legs

16 and 18, respectively.

In the hollow fiber membrane element 1,

outlet ports

40a and 40b are formed at both ends in the longitudinal direction of the second water collecting pipe 14, respectively. The outlet may be located at any position or on the column as long as the outlet can take out the treated water collected in the water collecting pipe through the hollow fiber membrane.

1.2 hollow fiber Membrane

The hollow fiber membrane 11 is generally used as the hollow fiber membrane sheet 10 in which a plurality of hollow fiber membranes 11 are bundled into a sheet shape. The first water collecting pipe 12 is provided on the first opening end 10a side 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 second opening end portion 10b side on the opposite side of the first opening end portion 10a in the longitudinal direction of the hollow fiber membrane sheet 10.

The first tubular strut 16 is disposed on one side in the width direction of the hollow fiber membrane sheet 10, the first end 17a of the first tubular strut 16 is connected to the first end 13a of the first water collection pipe 12, and the second end 17b of the first tubular strut 16 is connected to the first end 15a of the second water collection pipe 14. The second tubular strut 18 is disposed on the other side in the width direction of the hollow fiber membrane sheet 10, the first end portion 19a of the second tubular strut 18 is connected to the second end portion 13b of the first water collection pipe 12, and the second end portion 19b of the second tubular strut 18 is connected to the second end portion 15b of the second water collection pipe 14.

The hollow fiber membrane element 1 can be arranged such that the first water collecting pipe 12 is positioned on the lower side and the second water collecting pipe 14 is positioned on the upper side, and the longitudinal direction of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 is the vertical direction.

The hollow fiber membrane sheet 10 is formed by bundling a plurality of hollow fiber membranes 11 in parallel with each other into a sheet shape. The number of hollow fiber membranes 11 in the hollow fiber membrane sheet 10 is not particularly limited, and may be set appropriately according to the membrane area, for example, 1000 to 6000 hollow fiber membranes 11, 2000 to 5000 hollow fiber membranes, or the like.

The hollow fiber membrane sheet 10 of this example is a laminate obtained by laminating a plurality of sheets in which a plurality of hollow fiber membranes 11 are arranged. In the present invention, the hollow fiber membrane sheet may be a laminate of such a plurality of sheets, or may be composed of one sheet.

Examples of the material of the hollow fiber membrane include polysulfone-based resins, polyacrylonitrile, cellulose derivatives, polyolefins such as polyethylene and polypropylene, fluorine-based resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene, polyamides, polyesters, polymethacrylates, and polyacrylates. Further, a material obtained by introducing a substituent to a part of these resins may be used. The hollow fiber membrane may be made of one kind of material, or two or more kinds of materials.

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

1.3 Water collecting pipe

As shown in fig. 3, the first header pipe 12 includes: a pair of

side walls

20a and 20b having long dimensions and opposing each other in the short-side direction of the first header pipe 12 and extending in the long-side direction of the first header pipe 12, and a bottom portion 20c having a semicircular cross section and connecting one end portions of the

side walls

20a and 20b (the lower end portions in fig. 3) to each other. The first water collecting pipe 12 has a U-shaped cross section orthogonal to the longitudinal direction. A slit-shaped opening 20d is formed in the first header pipe 12 on the side opposite to the bottom portion 20c, and the opening 20d extends in the longitudinal direction between the first end portion 13a and the second end portion 13 b. The first open end 10a of the hollow fiber membrane sheet 10 is inserted into the opening 20d of the first header pipe 12.

The bottom portion 20c has formed therein: a pair of

wall surfaces

50a, 50b opposed to each other with a space therebetween in the short side direction of the first header pipe 12 and extending in the long side direction of the first header pipe 12, and a bottom surface 50c connecting the lower end portions of the pair of

wall surfaces

50a, 50 b. The wall surface 50a and the wall surface 50b are arranged at an interval of the maximum length W in the short side direction of the first header pipe 12. The sectional shape of the bottom surface 50c perpendicular to the longitudinal direction of the first header pipe 12 is a semicircle having a radius W/2.

As shown in fig. 3, the first opening end portion 10a of the hollow fiber membrane sheet 10 is inserted into the opening 20d of the first header pipe 12 in a state of being accommodated in the cast housing 23 and fixed to the cast housing 23 by the cast portion 23b made of a cured material of cast resin. The casting case 23 is fixed to the first header pipe 12 by a casting portion 22a made of a cured material of casting resin. Further, a portion of the first opening end portion 10a of the hollow fiber membrane sheet 10 on the opening 20d side of the potting case 23 is fixed to the first water collecting pipe 12 by a potting portion 23a made of a cured potting resin.

Thus, the hollow fiber membranes 11 and the first header pipes 12 are fixed by the

potting portions

22a, 23 b. The bottom 20c side of the first header pipe 12 with respect to the pouring

portions

22a and 23b is a first water collecting passage 20e (water collecting passage). That is, the first header pipe 12 has a first water collecting channel 20e having the pouring

portions

22a and 23b and the first header pipe 12 as wall surfaces therein.

In the first open end 10a of the hollow fiber membrane sheet 10, the inside of each hollow fiber membrane 11 communicates with the first water collecting channel 20e of the first water collecting pipe 12.

The cross-sectional area of the first water collecting channel 20e, which is arbitrary and perpendicular to the longitudinal direction, of the first water collecting pipe 12 is 100mm ²～350mm²Preferably 150mm²～300mm²More preferably 250mm²～280mm². When the cross-sectional area is within this range, the increase in flow resistance can be suppressed within an allowable range, and excellent pressure resistance can be ensured.

As the first water collecting pipe 12, the cross-sectional area of the first water collecting channel 20e is preferably within the above range at any position in the longitudinal direction of the first water collecting pipe 12. However, the first water collecting pipe 12 is not limited thereto, and only a part of the cross-sectional area of the first water collecting channel 20e in the longitudinal direction may be within the above range.

The length H in the longitudinal direction of hollow fiber membranes 11 in the cross section of the water collecting channel perpendicular to the longitudinal direction of first water collecting pipe 12 (also referred to as the height H of the water collecting channel) is preferably 20mm or less, more preferably 15 to 20mm, still more preferably 16mm to 20mm, and particularly preferably 17mm to 19 mm. As shown in fig. 3, the length H is a distance from an end surface of the first water collecting pipe 12 on the side of the bottom surface 50c of the pouring section 23b contacting the wall surfaces 50a and 50b to the bottom of the bottom surface 50c in the longitudinal direction of the hollow fiber membrane 11 in the cross section perpendicular to the longitudinal direction.

When the height H of the water collecting channel is 20mm or less, the pressure resistance can be further improved, and water leakage is less likely to occur even if reverse cleaning under high pressure is performed.

The maximum length W of the short-side direction interval of the wall surfaces 50a, 50b and the height H of the water collecting channel preferably satisfy the relationship of H < 1.2 x W. Within this range, it becomes easy to suppress the retention of water.

In addition, when the maximum length W of the water collecting passage becomes large, more membranes can be put in the water collecting pipe, so that the amount of water that can be treated per unit time increases. In addition, the water in the water collecting pipe is easily updated, and the water stored at the lower part of the water collecting pipe is discharged to improve the water quality.

As shown in fig. 3A to 3H, as another means for improving the pressure resistance of the first header pipe 12, a deformation suppressing member 21a for suppressing deformation of the wall of the first header pipe 12 may be provided. Further, a member 21 for supporting the deformation suppressing member 21a may be further provided. The deformation suppressing member 21a suppresses the deformation of the water collecting passage expanding outward even when the backwashing is performed at a high pressure, and the pressure resistance is further improved, thereby further making it difficult for water leakage to occur. Further, by providing the deformation inhibiting members 21a, even if the hollow fiber membrane element 1 is impacted, only the deformation inhibiting members 21a are broken, and the water collecting passage is hard to be broken.

The deformation inhibiting member 21a is preferably arranged over seven or more longitudinal lengths of the first header pipe 12.

The deformation suppressing member 21a is preferably a rib for reinforcement, but may be a reinforcing member other than a rib as long as deformation of the wall of the first header pipe 12 can be suppressed.

As shown in fig. 3A, 3B, and 3F to 3H, the deformation inhibiting member 21a may be provided outside the first header pipe 12, or as shown in fig. 3C to 3E, the deformation inhibiting member 21a may be provided inside the first header pipe 12, that is, on the side of the first water collecting passage 20E.

The deformation inhibiting member 21a may be provided to contact the wall of the header pipe as a member different from the first header pipe 12, or may be connected to and integrated with the first header pipe 12.

As shown in fig. 3A to 3H, in the cross section perpendicular to the longitudinal direction of the first header pipe 12, the deformation inhibiting member 21a is formed to have a width not exceeding the maximum width defined by the distance between the outer side surfaces of the pair of

side wall portions

20a, 20 b. Therefore, the first header pipe 12 having the deformation inhibiting member 21a does not increase the overall size. For example, even if the vehicle collides during maintenance work, the damage can be suppressed by structural reinforcement, and the deformation suppressing member 21a receives the impact at the time of collision, whereby the damaged portion can be replaced with the deformation suppressing member 21a from the header pipe.

As shown in fig. 3, the first header pipe 12 preferably has a step 20g on the inner surface of the pair of

side walls

20a and 20b, and is joined to the lower portion of the pouring section 22a on the surface of the step 20g facing the opening 20 d. The presence of such a step 20g is preferable because the range of engagement in the shearing direction increases with respect to the force that the wall of the water collecting channel is intended to expand outward during pressurization. In addition, since the joint area is increased and the joint force is improved, the joint strength between the header pipe and the pouring portion is increased, and the joint portion is easily prevented from being peeled off by an impact at the time of collision.

The width of the step 20g in the short side direction of the first header pipe 12 is preferably 0.5mm or more, more preferably 1.5mm or more, and still more preferably 2.0mm to 3.0 mm.

The surface roughness of the joint surface of the first header pipe 12 with the pouring section 22a is defined as a surface roughness measured in accordance with JIS B0601: 2001, preferably Ra6.3 to 25. When the surface roughness is within this range, the bonding strength between the first water collecting pipe 12 and the pouring section 22a is further increased, and the durability of the hollow fiber membrane element 1 is further improved, so that the hollow fiber membrane element can easily withstand a plurality of times of high pressure reverse cleaning. In addition, the joint strength between the header pipe and the pouring portion is increased, and the joint portion is easily prevented from peeling off due to an impact at the time of collision.

The surface roughening is classified into a case of performing roughening on the header pipe main body and a case of performing roughening on a molding die of the header pipe. The water collecting pipe body may be subjected to sand blasting or filing, and the water collecting pipe mold may be subjected to shot blasting or chemical etching.

The joint surface of the first header pipe 12 with the pouring section 22a preferably has irregularities. If the joint surface has irregularities, the joint strength between the first water collecting header 12 and the pouring section 22a further increases, and the durability of the hollow fiber membrane element 1 further improves, and the hollow fiber membrane element is easily subjected to multiple times of high pressure reverse cleaning. In addition, the joint strength between the header pipe and the pouring portion is increased, and the joint portion is easily prevented from peeling off due to an impact at the time of collision.

Examples of the irregularities of the bonding surface include a square shape and a wave shape. The height (height difference) of the irregularities is preferably 0.3mm to 1.0mm, more preferably 0.4mm to 0.6 mm. When the unevenness is within this range, the joining force of the potting liquid applied to the joining surface can be improved, and the potting liquid can be easily prevented from flowing into the water collection channel when the potting liquid is injected, which is preferable.

As described above, the description of the first water collecting pipe 12 in the "1.3 water collecting pipe" includes a form in which the open end of the hollow fiber membrane sheet is inserted into the water collecting pipe, and the cross-sectional area of the water collecting passage corresponds to the second water collecting pipe 14. In the hollow fiber membrane element 1, the second water collection header 14 is disposed on the opposite side of the first water collection header 12 side in the longitudinal direction of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 in a state of being inverted vertically from the first water collection header 12, that is, in a state of having its opening directed downward. The second open end 10b of the hollow fiber membrane sheet 10 is fixed by a potting portion in a state where the slit-shaped opening of the second water collecting pipe 14 is inserted and the end face of each hollow fiber membrane 11 is opened.

The first header pipe 12 and the second header pipe 14 may be the same or different, but preferably have the same configuration.

The water collecting pipe is preferably made of a material having excellent mechanical strength and durability, and 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 can be one or more than two.

Examples of the casting resin for forming the casting portion include epoxy resin, unsaturated polyester resin, polyurethane resin, silicone-based filler, and various hot-melt resins. One or more kinds of casting resins may be used to form the casting portion.

1.4 support post

Fig. 4 is a B-B sectional view of the hollow fiber membrane element of fig. 1.

As shown in fig. 4, the first tubular strut 16 has a water passage 61 inside as a portion through which the supply water passes. The water passage 61 located inside the first tubular pillar 16, the first water collection passage 20e located inside the first water collection pipe 12, and the second water collection passage 20f located inside the second water collection pipe 14 communicate with each other. Similarly, the second tubular post 18 has a water passage inside as a portion through which the water passes. The water passage located inside the second tubular post 18, the first water collection passage 20e located inside the first water collection pipe 12, and the second water collection passage 20f located inside the second water collection pipe 14 communicate with each other.

The cross-sectional area of the water collecting channel of the water collecting pipe is preferably equal to or less than the cross-sectional area of the water passage of the pillar. When the cross-sectional area of the water collecting channel of the water collecting pipe is larger than the cross-sectional area of the water collecting channel of the strut, in other words, when the cross-sectional area of the water passing channel of the strut is smaller than the cross-sectional area of the water collecting channel of the water collecting pipe, suction pressure at the time of collecting the treated water collected by the hollow fiber membranes to the water collecting channel through the water passing channel by the operation of the suction pump or the like may be lost in the water passing channel and not sufficiently applied to the water collecting channel, resulting in a decrease in water permeability. On the other hand, when the cross-sectional area of the water collecting passage of the water collecting pipe is equal to or smaller than the cross-sectional area of the water passage of the pillar, it is easy to suppress pressure loss in the water passage and maintain water permeability.

In this way, by setting the cross-sectional area of the water collecting channel in the plane perpendicular to the longitudinal direction of the water collecting pipe to be equal to or smaller than the cross-sectional area of the water passage, it is possible to easily suppress pressure loss in the water passage and maintain water permeability. Further, the cross-sectional area of the water collection channel can be secured without changing the size of the hollow fiber membrane element, and the deformation suppressing member can be easily provided below the water collection channel or the water collection pipe because there is a margin in the size in the height direction.

Preferably, the cross-sectional area of any surface of the water passage of the pillar perpendicular to the longitudinal direction is a, and the cross-sectional area of any surface of the water collection passage of the water collection pipe perpendicular to the longitudinal direction is b, so that a relation of 0.5 × a ≦ b is satisfied. When the cross-sectional area b of the water collecting passage is smaller than 0.5 × a, the pressure loss in the water collecting passage is large, and the water permeability may be lowered. Therefore, by satisfying the relationship of 0.5 xa. ltoreq.b, the water permeability of each hollow fiber membrane 11 is easily maintained.

The cross-sectional area a of the water passage 61 of the first tubular pillar 16 and the cross-sectional area b of the first water collecting passage 20e of the first water collecting pipe 12₁Ratio of (a)/(b)₁And the cross-sectional area a of the water passage 61 of the first tubular pillar 16 and the cross-sectional area b of the second water collecting channel 20f of the second water collecting pipe 14₂Ratio of (a)/(b)₂Each is preferably 0.7 or more, more preferably 0.9 or more, and preferably satisfies both of the formula (1) and the formula (2).

a/b₁≥0.9···(1)

a/b₂≥0.9···(2)

By making the ratio a/b₁And the ratio a/b₂Each of the amounts is preferably 0.7 or more, because the pressure loss in the water passage 61 of the first tubular strut 16 in the hollow fiber membrane element 1 is more likely to be reduced.

The ratio of the cross-sectional area of the water passage of the second tubular strut 18 to the cross-sectional area of the first water collecting passage 20e of the first water collecting pipe 12 and the ratio of the cross-sectional area of the water passage of the second tubular strut 18 to the cross-sectional area of the second water collecting passage 20f of the second water collecting pipe are also the same.

The cross-sectional area a of the water passage 61 of the first tubular pillar 16 and the cross-sectional area b of the first water collecting passage 20e of the first water collecting pipe 12₁And a sectional area b of the second water collecting passage 20f of the second water collecting pipe 14₂It is further preferable that the formula (3) and the formula (4) are satisfied at the same time. This makes it easier to maintain the water permeability of each hollow fiber membrane 11.

0.5×a≤b₁···(3)

0.5×a≤b₂···(4)

The cross-sectional area of the water passage as the strut can be set to 150mm, for example²～400mm²。

The form of the pillar is not particularly limited, and examples thereof include a quadrangular cylindrical form and a cylindrical form.

The material of the support is not particularly limited, and examples thereof include stainless steel (SUS).

1.5 protrusions

As shown in fig. 4 and 5, the first end portion 13a of the first header pipe 12 includes: a cylindrical portion 24a communicating with the first water collecting passage 20e, a tubular projection portion 24b provided to project toward the opening portion 20d side of the cylindrical portion 24a, and a peripheral wall portion 24c provided to surround the periphery of the projection portion 24 b. Two of the four peripheral wall portions 24c are provided apart from the protrusion portion 24b on the cylindrical portion 24a on both sides in the longitudinal direction of the first header pipe 12 of the protrusion portion 24b, and are opposed to each other. The remaining two of the four peripheral wall portions 24c are provided so as to be separated from the projections 24b on the cylindrical portion 24a on both sides in the short-side direction of the first header pipe 12 of the projections 24b, face each other, and become continuous walls integrally with the

side wall portions

20a, 20b, respectively.

Of the four peripheral wall portions 24c surrounding the protrusion 24b, the upper end of the peripheral wall portion 24c on the longitudinal direction center side of the first water collecting pipe 12, that is, on the side closer to the first opening end portion 10a of the hollow fiber membrane sheet 10 is slightly lower than the upper ends of the

side wall portions

20a, 20 b. The remaining three peripheral wall portions 24c, that is, the peripheral wall portion 24c on the end surface side of the first header pipe 12 and the upper ends of the pair of opposed peripheral wall portions 24c in the short-side direction have the same height as the upper ends of the

side wall portions

20a, 20 b.

The tubular projection 24b provided at the first end 13a of the first header pipe 12 is a portion for connection to the first tubular post 16. The inside of the protrusion 24b communicates with the inside of the cylindrical portion 24 a. The shape of the protrusion 24b is not particularly limited, and examples thereof include a quadrangular cylinder shape and a cylindrical shape.

The height of the protrusion 24b is preferably 5 to 30mm, and more preferably 10 to 20 mm. If the height of the projection 24b is equal to or greater than the lower limit of the above range, the connection strength between the projection 24b and the first tubular strut 16 is easily increased. If the height of the protrusion 24b is not more than the upper limit of the above range, the formability is improved.

The second end portion 13b of the first header pipe 12 has the same form as the first end portion 13a, and preferably has a tubular projection for connecting to the second tubular brace 18.

The first end 15a and the second end 15b of the second header pipe 14 may be in the same form as the second end 13b of the first header pipe 12, and preferred forms are also the same.

1.6 removal opening

A take-out port for taking out the treated water is formed in an end surface of at least one of the first header pipe 12 and the second header pipe 14. In the end surface of the first header pipe 12 on the first end portion 13a side in this example, the opening 24d of the cylindrical portion 24a is closed by the cover member 25. 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.

1.7 tubular casing

In fig. 4 and 5, the protrusion 24b of the first end 13a of the first header pipe 12 is inserted into the first end 17a of the first tubular strut 16 in a state where the tubular bushing 26 is attached, but the tubular bushing 26 may be omitted. Alternatively, the tubular sleeve 26 may be formed integrally with the first header.

When the tubular sleeve 26 is attached, the first end portion 17a of the first tubular strut 16 and the first end portion 13a of the first header pipe 12 are connected in a state where the interior of the first tubular strut 16 and the first water collecting channel 20e inside the first header pipe 12 communicate with each other via the projection 24b and the tubular sleeve 26.

Similarly, the projection of the second end portion 13b of the first header pipe 12 may be inserted into the first end portion 19a of the second tubular strut 18 in a state in which the tubular sleeve is attached, and the first end portion 19a of the second tubular strut 18 and the second end portion 13b of the first header pipe 12 may be connected in a state in which the interior of the second tubular strut 18 and the first water collecting channel 20e inside the first header pipe 12 communicate via the projection and the tubular sleeve. The tubular sleeve can be omitted. Alternatively, the tubular sleeve 26 may be formed integrally with the second header.

The projection of the first end 15a of the second water collecting pipe 14 may be inserted into the second end 17b of the first tubular strut 16 in a state where the tubular sleeve is attached, and the second end 17b of the first tubular strut 16 and the first end 15a of the second water collecting pipe 14 may be connected in a state where the interior of the first tubular strut 16 and the second water collecting channel 20f in the interior of the second water collecting pipe 14 communicate with each other via the projection and the tubular sleeve.

The projection of the second end portion 15b of the second header pipe 14 may be inserted into the second end portion 19b of the second tubular strut 18 in a state where the tubular sleeve is attached, and the second end portion 19b of the second tubular strut 18 and the second end portion 15b of the second header pipe 14 may be connected in a state where the inside of the second tubular strut 18 and the second water collecting channel 20f inside the second header pipe 14 communicate with each other via the projection and the tubular sleeve.

1.8 resins

The resin 30 is filled around the first end 17a of the first tubular brace 16 inside the peripheral wall 24c of the first end 13a of the first header pipe 12. Thereby, the insertion portion 28 of the first tubular strut 16 is fixed in a watertight sealed state by the resin 30 in such a manner that the inside and the outside thereof are isolated.

It is preferable that the gap between the first tubular strut 16 and the projection 24b in the insertion portion 28 is sealed watertight by the resin 30.

The resin 30 is not particularly limited, and a known curable resin can be used without particular limitation. The resin 30 is preferably a hard resin having a shore a hardness of 80 or more as measured in accordance with JIS C2105, from the viewpoints of higher bonding strength to the tubular strut and excellent water tightness. When the resin 30 is a hard resin, the shore a hardness is preferably 99 or less, since a portion of the resin 30 is hard to break. As the resin 30, a soft resin having a shore a hardness of less than 80 may be used.

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

Examples of the soft resin include a polyurethane resin, a silicone filler, and various hot-melt resins.

The protrusion 24b preferably tapers toward the tip. This makes it easy to insert the first tubular support 16 and to prevent the resin 30 injected around the projection 24b from peeling off when the first tubular support 16 is inserted. In addition, demolding in the production of the first header pipe 12 by injection molding becomes easy.

The outer surface of the first end 17a of the first tubular strut 16 is preferably grit blasted. In the present invention, it is preferable that the outer surfaces of the end portions of the first tubular strut and the second tubular strut are sandblasted. The insertion portions into which the protruding portions of the outer surfaces of the end portions of the first tubular strut and the second tubular strut are inserted into their end portions are in contact with resin that is water-tightly sealed and fixed in such a manner as to isolate the communicating interior and exterior of the insertion portions. By performing the sand blasting on the outer surfaces of the end portions of the first tubular strut and the second tubular strut, the adhesion between the tubular strut and the resin can be improved, and the strength of the hollow fiber membrane element can be improved.

The method of the blasting treatment is not particularly limited.

1.9 pieces

In this example, the

blocks

32 and 34 are provided on both sides in the longitudinal direction of the first end portion 17a of the first tubular brace 16 inside the peripheral wall portion 24c of the first header pipe 12. The

blocks

32 and 34 are provided in a state of being embedded in the resin 30 filled inside the peripheral wall portion 24 c. This can prevent the support from falling down and being damaged even when a load is applied to the support.

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 for example, the same material as that listed as the material of the header pipe can be listed.

A part in which a part of the water collecting pipe is provided in a rectangular parallelepiped may be formed by integral molding processing to have a function equivalent to that of the block.

In the present invention, it is preferable that a first blocking portion that blocks the flow of the processing water flowing into the water collecting passage of the first water collecting pipe through the first opening end portion of the hollow fiber membrane sheet toward the first tubular pillar is provided on a first end side of the first opening end portion of the hollow fiber membrane sheet in the longitudinal direction of the first water collecting pipe, and a second blocking portion that blocks the flow of the processing water flowing into the water collecting passage of the second water collecting pipe through the second opening end portion of the hollow fiber membrane sheet toward the second end side of the second opening end portion of the hollow fiber membrane sheet in the longitudinal direction of the second water collecting pipe toward the second tubular pillar. This can suppress occurrence of variations in the portion of the hollow fiber membrane sheet used for treatment, and the hollow fiber membrane sheet can be efficiently used for treatment as a whole.

For example, in this example, as shown in fig. 2, a first locking portion 36 and a second locking portion 38 are provided on the first end portion 13a side of the first opening end portion 10a of the hollow fiber membrane sheet 10 in the longitudinal direction of the first water collecting pipe 12 and on the second end portion 15b side of the second opening end portion 10b of the hollow fiber membrane sheet 10 in the longitudinal direction of the second water collecting pipe 14, respectively.

Outlet ports

40a and 40b for taking out the treated water are formed in end faces of the first end 15a and the second end 15b of the second water collecting pipe 14.

The first latch 36 is a portion that blocks the flow of the treated water flowing into the first water collecting channel 20e to the first tubular strut 16 through the first open end 10a of the hollow fiber membrane sheet 10. The second locking portion 38 is a portion that blocks the flow of the treated water flowing into the second water collecting channel 20f through the second open end 10b of the hollow fiber membrane sheet 10 to the second tubular strut 18.

The form of the first and

second locking portions

36 and 38 is not particularly limited as long as it is within a range in which the flow of the treated water can be cut off.

As shown in fig. 2, in this manner, the treated water collected from the lower portion of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 to the first water collecting channel 20e of the lower first water collecting pipe 12 is sent to the second end portion 15b of the upper second water collecting pipe 14 through the second tubular support column 18, and is taken out from the outlet 40 b. The treated water in the second water collecting channel 20f of the second water collecting pipe 14, which is collected from the upper portion of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 to the upper portion, is sent to the first end portion 15a of the second water collecting pipe 14, and is taken out from the outlet 40 a. This enables the hollow fiber membrane sheet 10 to be efficiently used for the treatment as a whole.

For example, as shown in fig. 6, a first locking portion 36 may be provided at the center of the first header pipe 12 in the longitudinal direction, a second locking portion 38 may be provided at the center of the second header pipe 14 in the longitudinal direction, and

outlet ports

40a and 40b for taking out the treated water may be formed in the end surfaces of the first end portion 15a and the second end portion 15b of the second header pipe 14.

In this configuration, the first locking portion 36 blocks the flow of the treated water flowing into the first water collecting channel 20e through the first open end 10a of the hollow fiber membrane sheet 10 on the first end 13a side toward the second end 13b, and blocks the flow of the treated water flowing into the first water collecting channel 20e through the first open end 10a of the hollow fiber membrane sheet 10 on the second end 13b side toward the first end 13 a. The second blocking portion 38 blocks the flow of the treated water flowing into the second water collecting channel 20f through the second open end 10b of the hollow fiber membrane sheet 10 on the first end 15a side toward the second end 15b, and blocks the flow of the treated water flowing into the second water collecting channel 20f through the second open end 10b of the hollow fiber membrane sheet 10 on the second end 15b side toward the first end 15a side.

In this manner, as shown in fig. 6, the treated water collected from the lower portion of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 on the first end portion 13a side to the first water collection channel 20e of the lower first water collection pipe 12 is sent to the first end portion 15a of the upper second water collection pipe 14 through the first tubular support 16, and is taken out from the outlet 40 a. The treated water in the second water collection channel 20f of the second water collection pipe 14, which is collected from the upper portion of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 on the first end 13a side to the upper side, is sent to the first end 15a of the second water collection pipe 14 and is taken out from the outlet 40 a.

The treated water collected from the lower portion of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 on the second end 13b side to the first water collecting channel 20e of the lower first water collecting pipe 12 is sent to the second end 15b of the upper second water collecting pipe 14 through the second tubular support column 18, and is taken out from the outlet 40 b. The treated water in the second water collecting channel 20f of the second water collecting pipe 14, which is collected from the upper portion of each hollow fiber membrane 11 of the hollow fiber membrane sheet 10 on the second end 13b side to the upper portion, is sent to the second end 15b of the second water collecting pipe 14, and is taken out from the outlet 40 b. This enables the hollow fiber membrane sheet 10 to be efficiently used for the treatment 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 number and position of the ejection ports are not limited to those described above, and can be set as appropriate.

The hollow fiber membrane element may be used in a state where the longitudinal direction of each hollow fiber membrane arranged in a hollow fiber membrane sheet is horizontal.

2. Method for manufacturing hollow fiber membrane element

The method for producing the hollow fiber membrane element of the present invention is not particularly limited. Hereinafter, a method for producing the hollow fiber membrane element 1 described above will be described as an example of a method for producing a hollow fiber membrane element of the present invention.

Examples of the method for producing the hollow fiber membrane element 1 include a method having the following steps (a) to (e).

Step (a): the first end and the second end of each of the plurality of hollow fiber membranes 11 bundled in a sheet form are inserted into a casting case, and a casting resin is injected and hardened to fix the hollow fiber membrane sheet-like object to the casting case.

Step (b): the tip end portion of the cast shell to which the hollow fiber membranes 11 are fixed is cut off, thereby obtaining the hollow fiber membrane sheet 10.

Step (c): a first tubular brace 16 and a second tubular brace 18 are connected to the raised portions of the first end 13a and the second end 13b of the first header pipe 12.

Step (d): a protrusion connecting the first and second

tubular legs

16, 18 to the first and

second ends

15a, 15b of the second header pipe 14.

A step (e): the first open end 10a of the hollow fiber membrane sheet 10 is inserted into the first header pipe 12 and fixed by the casting portion, and the second open end 10b of the hollow fiber membrane sheet 10 is inserted into the second header pipe 14 and fixed by the casting portion.

The water collection pipe is provided with a deformation suppressing member as required.

3. Hollow fiber membrane module

The hollow fiber membrane module of the present invention includes a plurality of hollow fiber membrane elements of the present invention. The hollow fiber membrane module of the present invention may be provided with a plurality of hollow fiber membrane elements of the present invention, and a known method may be employed.

In the hollow fiber membrane module of the present invention, for example, the plurality of hollow fiber membrane elements may be arranged so that the hollow fiber membrane sheet-like objects face each other and are spaced apart from each other in a direction perpendicular to the hollow fiber membrane sheet-like objects. Further, a plurality of units in which a plurality of hollow fiber membrane elements are arranged in this manner may be formed, and these plurality of units may be stacked one on top of another.

4. Effect of action

The hollow fiber membrane element of the utility model is characterized in that the sectional area of a water collecting channel on a surface of a water collecting pipe vertical to the long edge direction is set to be 100-350 mm²Thereby having good pressure resistance. Therefore, even if pressure is applied to the inside of the water collecting pipe during the backwashing at high pressure, the water collecting pipe can be prevented from being damaged and leaking.

The hollow fiber membrane element and the hollow fiber membrane module of the present invention are not particularly limited in their applications, and can be used for drainage treatment, and also for production of purified water such as sterile water, drinking water, and high purity water. The hollow fiber membrane element of the present invention has excellent pressure resistance capable of withstanding backwashing, and is therefore particularly useful for production of purified water.

5. Water treatment device

The water treatment apparatus of the present invention includes the hollow fiber membrane module of the present invention and an air diffuser disposed below the hollow fiber membrane module.

The air diffusing device is not particularly limited, and a known air diffusing device for cleaning a membrane can be used without limitation.

Examples of the water treatment device of the present invention include a device used in a membrane separation active sludge (MBR) method, and a water purification device for treating river water and the like.

6. Water treatment method

The water treatment method of the present invention is a method of treating water using the water treatment apparatus of the present invention. The water treatment method of the present invention is not particularly limited, and examples thereof include a membrane-separated activated sludge (MBR) method and a water purification treatment of river water.

Examples

The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following descriptions.

[ example 1]

A hollow fiber membrane element having the same form as the hollow fiber membrane element 1 illustrated in fig. 1 to 3 was produced.

The sectional area b of the first water collecting channel of the first water collecting pipe₁And a sectional area b of a second water collecting path of the second water collecting pipe₂Are respectively set to 300mm²The heights H of the first and second water collecting channels are set to 18mm, and the ratio a/b is set to₁And the ratio a/b₂Each set to 1.28.

[ example 2]

The configuration of the first and second water collecting pipes was changed to the configuration having the deformation suppressing member shown in fig. 3A, and the cross-sectional area, height H, and ratio a/b of the first and second water collecting passages were changed as shown in table 1 ₁And the ratio a/b₂A hollow fiber membrane element having the same configuration as in example 1 except for the above.

[ example 3]

The configuration of the first and second water collecting pipes was changed to the configuration having the deformation suppressing member shown in fig. 3A, and the cross-sectional area, height H, and ratio a/b of the first and second water collecting passages were changed as shown in table 1₁And the ratio a/b₂Hollow fiber having the same form as example 1 except forA vascular element.

Comparative example 1

A hollow fiber membrane element was produced in the same manner as in example 1, except that the first water collecting pipe and the second water collecting pipe were changed to have the deformation suppressing member shown in fig. 3A, the cross-sectional area and the height H of the first water collecting channel and the second water collecting channel were changed as shown in table 1 without providing a support.

Comparative example 2

The cross-sectional area, height H, and ratio a/b of the first water collecting channel and the second water collecting channel were changed as shown in Table 1₁And the ratio a/b₂A hollow fiber membrane element having the same configuration as in example 1 except for the above.

[ withstand voltage test ]

In the hollow fiber membrane elements of the respective examples, the respective hollow fiber membranes were cut at the positions of the openings of the first header pipe and the second header pipe, and the cut portions were closed by potting resin. Then, water is supplied to each water collecting pipe, and the water pressure is gradually increased until the water collecting pipe is damaged and water leakage occurs. Table 1 shows the water pressure at the time of water leakage in the hollow fiber membrane elements of the respective examples.

TABLE 1

As shown in table 1, the hollow fiber membrane elements of examples 1 to 3 in which the cross-sectional area of the water collecting pipe is within an appropriate range have higher water pressure at the time of water leakage and excellent pressure resistance, as compared with the hollow fiber membrane element of comparative example 1 in which the cross-sectional area of the water collecting pipe is small and the hollow fiber membrane element of comparative example 2 in which the cross-sectional area of the water collecting pipe is large. The hollow fiber membrane elements of examples 2 and 3 provided with the deformation inhibiting member have better pressure resistance than the hollow fiber membrane element of example 1 not provided with the deformation inhibiting member.

Claims

1. A hollow fiber membrane element having: a hollow fiber membrane, a water collecting pipe, and a discharge port for discharging treated water from the water collecting pipe,

the cross section area of any water collecting path section of the water collecting pipe vertical to the long edge direction is 100-350 mm²。

2. The hollow fiber membrane element of claim 1,

the length of the water collection channel in the longitudinal direction of the hollow fiber membrane is 20mm or less.

3. The hollow fiber membrane element of claim 1 or 2,

the water collection pipe has at least one of a deformation suppressing member in contact with a wall of the water collection pipe and a deformation suppressing member integrated with the water collection pipe.

4. The hollow fiber membrane element of claim 3,

the deformation inhibiting member is a rib.

5. The hollow fiber membrane element of claim 1 or 2,

the water collecting pipe has a step, and the step is engaged with a lower portion of the pouring section.

6. The hollow fiber membrane element of claim 5,

the step is more than 0.5 mm.

7. The hollow fiber membrane element according to claim 1 or 2,

8. The hollow fiber membrane element of claim 7,

and the water passage inside the support is respectively communicated with the first water collecting passage of the first water collecting pipe and the second water collecting passage of the second water collecting pipe.

9. The hollow fiber membrane element of claim 8,

when the cross-sectional area of any surface of the water collecting passage of the water collecting pipe perpendicular to the longitudinal direction is b, and the cross-sectional area of any surface of the water passage of the support perpendicular to the longitudinal direction is a, the relation of 0.5 x a ≤ b is satisfied.

10. The hollow fiber membrane element of claim 9,

the following formula (1) and formula (2) are satisfied:

a/b₁≥0.9···(1)

a/b₂≥0.9···(2)

b₁the cross-sectional area of any surface of the first water collecting channel of the first water collecting pipe perpendicular to the longitudinal direction,

b₂the cross-sectional area of an arbitrary surface of the second water collecting passage of the second water collecting pipe perpendicular to the longitudinal direction.

11. The hollow fiber membrane element according to claim 9 or 10,

the following formula (3) and formula (4) are satisfied:

0.5×a≤b₁···(3)

0.5×a≤b₂···(4)

12. A hollow fiber membrane module characterized in that,

A hollow fiber membrane element comprising a plurality of hollow fiber membrane elements according to any one of claims 1 to 11.

13. A water treatment device is characterized in that,

the hollow fiber membrane module according to claim 12, and an air diffuser disposed below the hollow fiber membrane module are provided.