JP2009136798A - Hollow fiber membrane module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow fiber membrane module with a controlled decrease in filtration area. <P>SOLUTION: The hollow fiber membrane module 10 to be sunk in a liquid L, has a hollow fiber membrane bundle 11 having a plurality of hollow fiber membranes 11A, a fixation part 13 in which each opened end 11s is fixed so that the opened end 11s of the plurality of hollow fiber membranes 11A maintains a determined distance each other, and a hollow room 13h communicating with a hollow part of the plurality of hollow fiber membranes 11A is formed, a dispersion part 14 in which a gas G is dispersed from the side of the opened end 11s toward the side of a closed end 11f in a part where the hollow fiber membranes 11A in the hollow fiber membrane bundle 11 and also outside hollow fiber membranes 11A are fixed to the fixation part 13, and a rectification plate 15 which guides a flow of surrounding part of the hollow fiber membrane bundle 11 of the flow of the liquid L generated by dispersing the gas G as a rectification directing from the side of opened end 11s to the closed end 11f, wherein each closed end 11f of the plurality of hollow fiber membranes 11A is structured as a free end. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hollow fiber membrane module, and more particularly to a hollow fiber membrane module that suppresses a reduction in filtration area.

Filtration using a hollow fiber membrane is widely used because it may have a merit that the hollow fiber membrane can take a wide membrane area in a unit volume. In a hollow fiber membrane module configured by bundling a plurality of hollow fiber membranes, both ends of each hollow fiber membrane are generally fixed with a potting material (for example, see Patent Document 1). However, when a fibrous substance or the like is contained in the raw water, the fibrous substance or the like may be entangled with the potting material to reduce the filtration area. In order to eliminate such inconvenience, there is a hollow fiber membrane module in which one end of the hollow fiber membrane is a free end and only the other end is fixed with a potting material (for example, see Patent Document 2).
Japanese Utility Model Publication No. 63-38884 (first page, FIG. 1 etc.) Japanese Patent Laid-Open No. 11-342321 (paragraph 0012, FIG. 3, etc.)

  However, a hollow fiber membrane module in which one end of the hollow fiber membrane is used as a free end and only the other end is fixed with a potting material cannot be maintained in the stretched state of the hollow fiber membrane. In some cases, a fibrous material or the like may be entangled in the formed portion.

  In view of the above-mentioned problems, the present invention provides a hollow fiber membrane module that suppresses a reduction in filtration area caused by entanglement of hollow fiber membranes or entanglement of residues such as fibrous substances with the hollow fiber membrane. With the goal.

  In order to achieve the above object, the hollow fiber membrane module according to the first aspect of the present invention is a hollow fiber membrane module 10 immersed in the liquid L, for example, as shown in FIG. A hollow fiber membrane bundle 11 having a plurality of hollow fiber membranes 11A having a closed end at the other end 11f; an open end so that the open ends 11s of the plurality of hollow fiber membranes 11A maintain a predetermined distance from each other 11s is fixed, and a fixed portion 13 is formed with a hollow chamber 13h communicating with the hollow portions of a plurality of hollow fiber membranes 11A; a hollow fiber membrane 11A inside the hollow fiber membrane bundle 11 and outside the hollow fiber membrane 11A A spout portion 14 that spouts the gas G from the opening end 11 s side toward the closed end 11 f side at the portion fixed to the fixing portion 13; Remove the hollow fiber membrane bundle 11 from the liquid L flow. Part of a rectifying plate 15 for guiding to the rectifier toward the closed end 11f of the flow from the open end 11s side winding; each closed end 11f of the plurality of hollow fiber membranes 11A is configured as a free end. Here, when the gas is discharged to the portion where the hollow fiber membrane is fixed to the fixing portion, typically, the gas is flowed at a position where the liquid surrounding the portion of the root of the hollow fiber membrane with respect to the fixing portion flows. It is to scatter.

  With this configuration, the spatter that gushes out the gas from the open end side to the closed end side in the portion where the hollow fiber membrane bundle inside and outside the hollow fiber membrane is fixed to the fixed portion Since the portion is provided, the liquid surrounding the portion of the root of the hollow fiber membrane with respect to the fixed portion can be made to flow by discharging the gas to the portion where the hollow fiber membrane is fixed to the fixed portion, so that the fibrous substance etc. It is possible to prevent the residue of the hollow fiber membrane from being entangled with the base portion of the hollow fiber membrane, and to contribute to maintaining the stretched state of the hollow fiber membrane by discharging gas from the open end side toward the closed end side Will be. In addition, since a flow regulating plate is provided for guiding the flow of the portion surrounding the hollow fiber membrane bundle in the flow of the liquid generated by the gas flowing out from the spout unit to be rectified from the opening end side toward the closing end. It is possible to prevent the liquid flow near the closed end (free end) from being disturbed and maintain the stretched state of the hollow fiber membrane, and prevent the hollow fiber membranes from being entangled with each other. Can do. Residues such as fibrous substances can be prevented from getting entangled with the root part of the hollow fiber membrane, and the hollow fiber membranes can be prevented from getting entangled with each other, thereby suppressing a decrease in the filtration area of the hollow fiber membrane module. be able to.

  In addition, when the hollow fiber membrane module according to the second aspect of the present invention is shown, for example, with reference to FIG. 2, in the hollow fiber membrane module 10 according to the first aspect of the present invention, the rectifying plate 15 is hollow. It is arrange | positioned so that the distance of 3 mm or more and 20 mm or less may be maintained from the outer edge of a thread membrane bundle.

  If comprised in this way, it can prevent that the downward flow of a liquid arises around a hollow fiber membrane bundle, and can prevent that hollow fiber membranes are intertwined.

  In addition, the hollow fiber membrane module according to the third aspect of the present invention is, for example, as shown in FIG. 2, in the hollow fiber membrane module 10 according to the first aspect or the second aspect of the present invention described above, the rectifying plate 15. However, it is arrange | positioned so that the hollow fiber membrane bundle 11 may be wrapped except for the end surfaces 11f and 11s direction of 11 A of hollow fiber membranes.

  With this configuration, it is possible to prevent the liquid flow from being disturbed all around the hollow fiber membrane bundle and maintain the stretched state of the hollow fiber membranes. Intertwining can be prevented.

  Moreover, when the hollow fiber membrane module according to the fourth aspect of the present invention is shown, for example, with reference to FIG. 1, the hollow fiber according to any one of the first to third aspects of the present invention described above. In the membrane module 10, the hollow fiber membrane bundle 11 is disposed so that the longitudinal direction of the hollow fiber membrane 11A is substantially vertical; the spreading portion 14 is in a state in which a plurality of hollow fiber membranes 11A extend in a substantially vertical direction. The gas G that creates the flow of the liquid L to be maintained is discharged. Here, the “state extending substantially in the vertical direction” is typically a state where the hollow fiber membranes are stretched so as not to be entangled with each other.

  If comprised in this way, the state in which the hollow fiber membranes extended reliably can be maintained, and it can prevent that hollow fiber membranes mutually entangle.

  According to the present invention, in the portion where the hollow fiber membrane inside the hollow fiber membrane bundle and the outside of the hollow fiber membrane is fixed to the fixing portion, the spout for discharging the gas from the opening end side toward the closing end side Since the portion is provided, the liquid surrounding the portion of the root of the hollow fiber membrane with respect to the fixed portion can be made to flow by discharging the gas to the portion where the hollow fiber membrane is fixed to the fixed portion, so that the fibrous substance etc. It is possible to prevent the residue of the hollow fiber membrane from being entangled with the base portion of the hollow fiber membrane, and to contribute to maintaining the stretched state of the hollow fiber membrane by discharging gas from the open end side toward the closed end side Will be. In addition, since a flow regulating plate is provided for guiding the flow of the portion surrounding the hollow fiber membrane bundle in the flow of the liquid generated by the gas flowing out from the spout unit to be rectified from the opening end side toward the closing end. It is possible to prevent the liquid flow near the closed end (free end) from being disturbed and maintain the stretched state of the hollow fiber membrane, and prevent the hollow fiber membranes from being entangled with each other. Can do. Residues such as fibrous substances can be prevented from getting entangled with the root part of the hollow fiber membrane, and the hollow fiber membranes can be prevented from getting entangled with each other, thereby suppressing a decrease in the filtration area of the hollow fiber membrane module. be able to.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or similar members are denoted by the same or similar reference numerals, and redundant description is omitted.

  First, a hollow fiber membrane module 10 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a partial longitudinal sectional view of a hollow fiber membrane module 10. The hollow fiber membrane module 10 includes a hollow fiber membrane bundle 11, a header 12 having a fixing portion 13 and a spout portion 14, and a rectifying plate 15. The hollow fiber membrane module 10 is immersed (immersed) in the liquid L when used.

  The hollow fiber membrane bundle 11 is configured by collecting a plurality of hollow fiber membranes 11A. The hollow fiber membrane 11A is a hollow yarn (hollow fiber) in which a straw-shaped (thin tubular) side surface in which a hollow portion is formed is a porous membrane portion. In the hollow fiber membrane 11A, the hollow portion communicating in the length direction penetrates the core of the hollow fiber. The outer diameter (diameter) of the hollow fiber membrane 11A is, for example, about 1 to 3 mm, but is preferably 2 mm or more from the viewpoint of facilitating self-sustaining in the liquid L. The thickness of the membrane constituting the hollow fiber membrane 11A is about 10 to 500 μm. The length of the hollow fiber membrane 11A can be set to 500 mm or more and the filtration area can be increased by appropriately arranging the current plate 15 as described later. The hollow fiber membrane 11A is typically made of a resin having water resistance and chemical resistance. Here, chemical resistance refers to resistance to chemicals mixed in the liquid L to be filtered when the hollow fiber membrane bundle 11 is used, and when the solid matter deposited on the surface of the hollow fiber membrane 11A is washed. Includes resistance to added chemicals. The hollow fiber membrane 11A is preferably made of a vinylidene fluoride resin. Vinylidene fluoride resin is excellent in heat resistance and mechanical strength in addition to chemical resistance. As the vinylidene fluoride-based resin, a homopolymer of vinylidene fluoride, that is, a polyvinylidene fluoride, a copolymer with another copolymerizable monomer, or a mixture thereof is used. As the monomer copolymerizable with the vinylidene fluoride resin, one or more of tetrafluoroethylene, hexafluoropropylene, ethylene trifluoride, ethylene trifluoride chloride, vinyl fluoride and the like can be used. . The vinylidene fluoride resin preferably contains 70 mol% or more of vinylidene fluoride, and is preferably a homopolymer composed of 100 mol% of vinylidene fluoride in view of high chemical resistance and mechanical strength. .

  11A of hollow fiber membranes account for 100 to 300 parts by weight of the plasticizer and the good solvent of the vinylidene fluoride resin in a total amount of 100 to 300 parts by weight of the vinylidene fluoride resin, and occupy the total amount of the plasticizer and the good solvent. It can add and manufacture so that the ratio of a solvent may be 8 to 35 weight%, and after extrusion molding, a plasticizer and a good solvent can be extracted with an extract. Furthermore, in order to increase the crystallinity, it is preferable to uniaxially stretch in the longitudinal direction after, for example, heat treatment at 100 to 140 ° C. for 3 to 900 seconds. By uniaxially stretching, the porosity and the pore diameter are increased, and the strength and linearity are improved. For example, in the hollow fiber membrane made of uniaxially stretched vinylidene fluoride resin, the porosity is 60 to 85%, the average pore diameter is 0.05 to 0.15 μm, the tensile strength is 5 MPa or more, and the elongation at break is 5%. That's it.

  The hollow fiber membrane 11A is formed at a closed end where a straw-like one end 11f is closed by a heat seal or the like, and at the other end 11s at an open end with an opening. 11 A of hollow fiber membranes are comprised so that the liquid L may be introduced and filtered into a hollow part from a straw-shaped outer peripheral surface, and the filtered liquid L may be derived | led-out from the other end 11s formed in the opening end. In the present embodiment, the hollow fiber membranes 11A, 11A,... Have the same configuration.

  The fixing | fixed part 13 is a member which fixes each hollow fiber membrane 11A, 11A, .... The fixing portion 13 is typically configured by forming a polymer synthetic resin having a small flexibility in a rectangular parallelepiped shape. The fixed portion 13 is formed with a liquid collection chamber 13h as a hollow chamber in which the inside of the rectangular parallelepiped is hollow. Each of the hollow fiber membranes 11A, 11A,... Is embedded in one surface of the rectangular parallelepiped of the fixed portion 13 so that the hollow portion communicates with the liquid collection chamber 13h, and the other end 11s. Are fixed to the fixing portion 13 so as to maintain a predetermined distance from each other. Here, the “predetermined interval” is an interval that does not hinder the flow of the liquid L between the hollow fiber membranes 11A, 11A,. The distance between the other ends 11s of the hollow fiber membranes 11A, 11A,... Is increased by increasing the number of hollow fiber membranes 11A per unit area on the surface of the fixing portion 13 to which the hollow fiber membrane 11A is fixed. From the viewpoint of making the entire 11 filtration area as large as possible, it is preferable to make it as narrow as possible within a range in which a predetermined interval can be maintained.

  One end 11f formed at the closed end of the hollow fiber membrane 11A is not supported and fixed to a member or the like, and is a free end movable in the liquid L. Since the one end 11f is a free end and is also a closed end, in the following description, the same reference numerals as the one end 11f are used to refer to the “free end 11f” and the “closed end 11f”. On the other hand, since the other end 11s is a fixed end and is also an open end, in the following description, the same reference numeral as the other end 11s is used to refer to the “fixed end 11s” and the “open end 11s”. The hollow fiber membrane 11A is hollow so that when the hollow fiber membrane bundle 11 constituting the hollow fiber membrane module 10 is immersed in the liquid L, the free end 11f is located at the upper part and the fixed end 11s is located at the lower part. The yarn film 11A itself is arranged to extend in the vertical direction. In the following description, when referring to the positional relationship such as the upper and lower sides, the hollow fiber membrane 11A is hollow so that the free end 11f is located at the upper part and the fixed end 11s is located at the lower part and the hollow fiber membrane 11A itself extends in the vertical direction. The positional relationship in the state when the yarn membrane module 10 is disposed shall be said. The hollow fiber membranes 11 </ b> A, 11 </ b> A,... Fixed to the fixing portion 13 described above are fixed to the upper surface of the rectangular parallelepiped of the fixing portion 13. Further, on the side surface of the rectangular parallelepiped of the fixing portion 13, a discharge port 13d for leading the liquid L in the liquid collection chamber 13h is formed.

  The squirting part 14 includes a main body 14b in which a polymer synthetic resin having a small flexibility similar to the cuboid of the fixing part 13 is formed in a cuboid, and a nozzle-like diffusing pipe 14p for discharging the gas G. ing. A hollow diffuser chamber 14h in which the gas G can exist is formed inside the rectangular parallelepiped body 14b. In the present embodiment, the spreading portion 14 and the fixing portion 13 are integrally configured as the header 12 so that the upper surface of the main body 14 b and the bottom surface of the rectangular parallelepiped of the fixing portion 13 are shared. The air diffuser 14p constituting the squirting part 14 is attached to the upper surface of the main body 14b so as to extend vertically upward from the upper surface of the main body 14b. The air diffuser 14p penetrates the liquid collection chamber 13h of the fixed portion 13 and the upper surface of the rectangular parallelepiped, and slightly protrudes from the upper surface of the rectangular parallelepiped of the fixed portion 13. The diffuser pipe 14p is attached so that the hollow portion inside thereof communicates with the space between the diffuser chamber 14h and the hollow fiber membrane 11A and does not communicate with the liquid collection chamber 13h. The gas G can be supplied to the space between the hollow fiber membranes 11A. The diffuser tube 14p has a hollow tip for each section obtained by virtually dividing the hollow fiber membrane bundle 11 into several small groups (for example, a group consisting of about eight hollow fiber membranes 11A, 11A,...). It is provided so as to open into the yarn membrane bundle 11 (so as to be sandwiched between a plurality of hollow fiber membranes 11A). The number of the air diffusers 14p and the installation interval can make the hollow fiber membranes 11A, 11A,... Stand in the liquid L so as to extend in the vertical direction, and the hollow fiber membranes 11A (hollow fiber membranes with respect to the fixing portion 13). What is necessary is just to determine suitably from a viewpoint of being able to supply the gas G which can produce the liquid flow of the grade which can remove the residue of fibrous substances etc. which are getting entangled in (including the base part of 11A). An inlet 14d for introducing the gas G into the diffuser chamber 14h is formed on the side surface of the main body 14b.

  The rectifying plate 15 is a member that guides the flow of the liquid L around the hollow fiber membrane bundle 11 generated when the gas G is discharged from the diffusing pipe 14p to rectify the flow from the fixed end 11s toward the free end 11f. It is. The “rectification” referred to here is typically a flow of the liquid L in a state where the hollow fiber membranes 11A are settled so as not to be entangled with each other. The rectifying plate 15 is typically formed of a polymer synthetic resin having a small flexibility, and is provided so that the hollow fiber membrane bundle 11 is hidden when the hollow fiber membrane module 10 is viewed in the horizontal direction. . That is, the rectifying plate 15 is disposed so as to wrap the hollow fiber membrane bundle 11 except for the upper and lower surfaces of the hollow fiber membrane bundle 11 (end surface of the hollow fiber membrane 11A). Alternatively, the rectifying plate 15 is disposed such that a gap is formed between the hollow fiber membrane module 10 and the fixing portion 13 when the hollow fiber membrane module 10 is viewed in the horizontal direction so that a connection portion between the hollow fiber membrane 11A and the fixing portion 13 can be seen. It may be. When the rectifying plate 15 is arranged in this way, the liquid L that flows from the fixed end 11 s toward the free end 11 f and is led out from the hollow fiber membrane module 10 flows between the rectifying plate 15 and the fixing portion 13. It can be reliably introduced into the space surrounded by the current plate 15 from the formed gap.

  As shown in the plan view of FIG. 2, the rectifying plate 15 is provided so as to surround the hollow fiber membrane bundle 11 when the hollow fiber membrane module 10 is viewed from vertically above. Further, when the hollow fiber membrane module 10 is viewed from vertically above, the rectifying plate 15 is a distance H (hereinafter referred to as “clearance H”) from the outer edge of the hollow fiber membrane bundle 11 in the plane of the connecting portion with the fixing portion 13. However, it is arranged so as to maintain a distance of 3 mm or more and 20 mm or less. Here, the outer edge of the hollow fiber membrane bundle 11 is connected with a tangent line common to the adjacent hollow fiber membranes 11A and 11A as a virtual line with respect to the hollow fiber membrane 11A constituting the outer peripheral portion of the hollow fiber membrane bundle 11. This is a virtual contour that occurs when In the example shown in FIG. 2, the outer edge of the hollow fiber membrane bundle 11 is rectangular. Therefore, the arrangement of the current plate 15 on the plane is preferably rectangular.

  FIG. 3 shows a graph of the relationship between the pressure loss and the clearance H when the liquid L flows through the clearance H portion. In the graph shown in FIG. 3, the horizontal axis represents the clearance H (mm), and the vertical axis represents the pressure loss P (kPa) of the flow of the liquid L. As shown in FIG. 3, when the clearance H is 4 mm or more, the pressure loss P is almost zero. On the other hand, when the clearance H falls below 4 mm, the pressure loss P starts to increase, and when the clearance H falls below 2 mm. The pressure loss P increases rapidly. By setting the clearance H to 3 mm or more, the pressure loss can be reduced to such an extent that the rectification of the upward flow of the liquid L generated between the rectifying plate 15 and the hollow fiber membrane bundle 11 is not hindered. From the viewpoint of reducing the above, it is preferable that the clearance H is 5 mm or more. On the other hand, the upper limit of the clearance H is preferably 20 mm. This is because if the clearance H is too large, a downward flow of the liquid L occurs inside the rectifying plate 15 to prevent the hollow fiber membrane 11A from becoming independent, and the hollow fiber membranes 11A may be entangled with each other.

  Returning to FIG. 2 again, the arrangement of the current plate 15 will be described. The rectifying plate 15 is disposed so that the fixing portion 13 does not exist below the clearance H portion formed along the longitudinal direction of the fixing portion 13 when the hollow fiber membrane module 10 is viewed from vertically above. . In other words, the relationship between the hollow fiber membrane bundle 11 and the fixing portion 13 is defined so that the fixing portion 13 does not exist below the clearance H portion. When the rectifying plate 15 is disposed at such a position, the liquid L flowing from the fixed end 11 s toward the free end 11 f and led out from the hollow fiber membrane module 10 is discharged in the longitudinal direction of the fixed portion 13. Can be reliably introduced into the clearance H portion from below the clearance H portion formed along the line. The hollow fiber membrane module 10 can avoid the occurrence of a downward flow around the hollow fiber membrane bundle 11 by including the current plate 15. The rectifying plate 15 configured as described above is configured so that the flow of the portion surrounding the hollow fiber membrane bundle 11 in the flow of the liquid L generated when the gas G is spouted from the spout portion 14 is on the opening end 11s side. The liquid L is guided from below to the hollow fiber membrane bundle 11 and led out from above to the inner side (the current plate 15 and the hollow fiber). The upward flow (between the membrane bundle 11) and the outward downward flow are partitioned. Four rectifying plates 15 connected so as to have a rectangular horizontal cross section (typically arranged so as to surround the four sides of the hollow fiber membrane bundle 11) receive liquid L from between the fixed portions 13. A liquid inlet for introduction and a liquid outlet for overflowing the liquid L from above are formed.

  Returning to FIG. 1 again, the description of the hollow fiber membrane module 10 will be continued. The hollow fiber membrane module 10 configured as described above is typically installed in a tank 21 in which the liquid L is placed. The hollow fiber membrane module 10 is installed such that the current plate 15 is immersed in the liquid L when used. A recovery liquid pipe 23 that conveys the filtered liquid L is connected to the outlet 13 d of the fixing unit 13. The recovery liquid pipe 23 is provided with a recovery liquid pump 25 that pumps the filtered liquid L. A gas transport pipe 24 that transports the gas G diffused from the air diffuser 14p is connected to the inlet 14d of the spout 14. A blower 26 that pressure-feeds the gas G toward the diffuser chamber 14h is disposed in the gas transport pipe 24.

  Next, the operation of the hollow fiber membrane module 10 will be described with reference to FIGS. 1 and 2. In the following description, it is assumed that the liquid L to be filtered is sewage (including wastewater) and the gas G is air. In addition, it is preferable that priming water is injected into the recovery liquid pipe 23 and the liquid collection chamber 13h in advance. The sewage L flows into the tank 21 at any time by a pump (not shown) or natural flow. The hollow fiber membrane module 10 is immersed in the sewage L. When the blower 26 is activated, the air G flows into the diffuser chamber 14h via the gas transport pipe 24, and further passes through the diffuser pipes 14p with the pressure of the blower 26, and from the upper ends of the diffuser pipes 14p to the hollow fiber membranes. It is discharged into the sewage L in the bundle 11. The air G discharged into the sewage L rises in the sewage L, and the rise of the air G causes an upward flow of the sewage L existing in the hollow fiber membrane bundle 11. Then, the upward flow of the sewage L existing in the hollow fiber membrane bundle 11 causes the upward flow of the sewage L existing in the clearance H portion inside the rectifying plate 15. By discharging the air G as a gas from the diffuser pipe 14p, an upward flow of the sewage L in the rectifying plate 15 can be created, and not only the residue of the fibrous substance but also the residue of the fibrous substance Solid matter and turbidity can also be removed from the hollow fiber membrane 11A. Moreover, when the air G is discharged from the diffuser pipe 14p, the sewage L can be discharged when activated sludge is used.

  The upward flow of the sewage L in the rectifying plate 15 flows out of the rectifying plate 15 from the upper end of the rectifying plate 15. The sewage L flowing out of the rectifying plate 15 descends outside the rectifying plate 15. The sewage L flows into the rectifying plate 15 from below the rectifying plate 15. As described above, the air G is discharged from the diffuser pipe 14p, thereby creating a flow of sewage L that rises inside the rectifying plate 15 and descends outside the rectifying plate 15. Since the flow straightening plate 15 is provided so that the clearance H of 3 mm to 20 mm is maintained, the flow of the sewage L can be partitioned inside and outside the flow straightening plate 15, and the sewage L descends inside the flow straightening plate 15. It is possible to prevent the flow from occurring. Further, the upward flow of the sewage L in the rectifying plate 15 prevents the hollow fiber membranes 11A from being entangled. Furthermore, since the free ends 11f of the hollow fiber membranes 11A located above are not potted (because they are not fixed), the entanglement of residues such as fibrous substances mixed in the sewage L to the hollow fiber membranes 11A Is also prevented.

  On the other hand, when the recovery liquid pump 25 is activated, the liquid in the recovery liquid pipe 23, the liquid collection chamber 13h, and the hollow fiber membrane 11A flows. Accordingly, the sewage L existing outside the hollow fiber membrane 11A flows into the hollow fiber membrane 11A. The sewage L is filtered by the sewage L flowing from the outside of the hollow fiber membrane 11A through the porous portion into the hollow portion of the hollow fiber membrane 11A. Since the sewage L existing outside the hollow fiber membrane 11A at this time is in an upward flow as described above, it is possible to perform a cross-flow filtration suitable for an ultrafiltration membrane. The sewage L that flows into the hollow portion of each hollow fiber membrane 11A and is filtered does not flow out from the closed end 11f, but flows into the liquid collection chamber 13h from the open end 11s and joins. The filtered sewage L that has merged in the liquid collection chamber 13h is conveyed to the next step (not shown) through the recovery liquid pipe 23.

  As described above, the hollow fiber membrane module 10 according to the present embodiment includes a hollow fiber membrane bundle 11 having a plurality of hollow fiber membranes 11A each having one end 11s formed at an open end and the other end 11f formed at a closed end. The fixed portion in which the open ends 11s are fixed so that the open ends 11s of the plurality of hollow fiber membranes 11A maintain a predetermined distance from each other, and a hollow chamber 13h communicating with the hollow portions of the plurality of hollow fiber membranes 11A is formed. 13 and a spout part 14 that spouts the gas G from the open end 11s side to the closed end 11f side inside the hollow fiber membrane bundle 11 and outside the hollow fiber membrane 11A. The flow of the liquid L can be created in the fixing part to the fixing part 13 of the hollow fiber membrane 11A, and a residue such as a fibrous substance can be prevented from being entangled with the hollow fiber membrane 11A in the vicinity of the fixing part. Further, the flow of the portion surrounding the hollow fiber membrane bundle 11 in the flow of the liquid L generated by the gas G being spouted from the spout portion 14 is rectified from the open end 11s side toward the closed end 11f (free end 11f). Therefore, the flow of the liquid L near the free end 11f can be prevented from being disturbed, and the hollow fiber membrane 11A can be maintained in an extended state. The hollow fiber membranes 11A can be prevented from being entangled with each other. Reduction of the filtration area of the hollow fiber membrane module 10 can be achieved by preventing residues such as fibrous substances from being entangled with the hollow fiber membrane 11A in the vicinity of the fixing site and preventing the hollow fiber membranes 11A from being entangled with each other. Can be suppressed.

  In the above description, the fixed portion 13 and the spout portion 14 are integrally formed to constitute the header 12. However, the fixed portion 13 and the spout portion 14 may be configured separately. .

  In the above description, the rectifying plate 15 is disposed so as to wrap the hollow fiber membrane bundle 11 except for the upper and lower surfaces of the hollow fiber membrane bundle 11 (so as to surround the four sides of the hollow fiber membrane bundle 11 on a plane). However, for example, as illustrated in FIG. 2, the hollow fiber membrane bundle 11 is a portion adjacent to the short side when the long side is formed in a rectangular shape having a sufficiently long long side compared to the short side on the horizontal plane. When there is a portion where the influence of the downward flow of the liquid L does not affect or has a small influence on the filtration function of the entire hollow fiber membrane module 10, the downward flow of the liquid L is similar to the portion adjacent to the short side. You may abbreviate | omit the part of the baffle plate 15 which is not influenced (or small). In the case of the example of FIG. 2, the rectifying plate 15 adjacent to the short side portion may be omitted, and the two rectifying plates 15 facing the long side may be installed.

  In the above description, the hollow fiber membrane module 10 is installed in the tank 21, but is directly immersed in a liquid that is not contained in the tank 21, for example, water accumulated in a pond or river water. It is good as well. In particular, when used in a liquid that does not flow, the flow (upflow) of the liquid L in the vicinity of the free end 11f is not disturbed, and the hollow fiber membranes 11A are less likely to be entangled with each other.

  In the above description, the liquid L to be filtered is sewage, but it may be, for example, drinking water or fruit juice other than sewage. The porous size of the hollow fiber membrane 11A may be appropriately determined according to the type of the liquid L. In addition, although the gas G is air, it may be an inert gas such as nitrogen. The use of an inert gas is suitable for filtering a liquid in which the use of oxygen is desired to prevent oxidation. The type of gas G to be used may be appropriately determined according to the type of liquid L to be filtered.

It is a fragmentary longitudinal cross-sectional view of the hollow fiber membrane module which concerns on embodiment of this invention. It is a top view of the hollow fiber membrane module which concerns on embodiment of this invention. It is a graph which shows the relationship between the pressure loss of a liquid flow, and clearance.

Explanation of symbols

10 hollow fiber membrane module 11 hollow fiber membrane bundle 11A hollow fiber membrane 11f free end (one end, closed end)
11s fixed end (other end, open end)
13 Fixing part 13h Hollow chamber 14 Spouting part 15 Current plate G Gas L Liquid

Claims (4)

A hollow fiber membrane module immersed in a liquid;
A hollow fiber membrane bundle having a plurality of hollow fiber membranes, one end being an open end and the other end being a closed end;
A fixed portion in which the open ends of the plurality of hollow fiber membranes are fixed so as to maintain a predetermined distance from each other, and a hollow chamber communicating with the hollow portions of the plurality of hollow fiber membranes is formed; ;
Spattering that emits gas from the opening end side toward the closed end side in a portion where the hollow fiber membrane inside the hollow fiber membrane bundle and outside the hollow fiber membrane is fixed to the fixing portion Part;
A rectifying plate that guides a flow of a portion surrounding the hollow fiber membrane bundle in a flow of the liquid generated by gas being discharged from the spout portion to be rectified from the opening end side toward the closing end. And comprising:
Each closed end of each of the plurality of hollow fiber membranes is configured as a free end;
Hollow fiber membrane module. The current plate is disposed to maintain a distance of 3 mm to 20 mm from an outer edge of the hollow fiber membrane bundle;
The hollow fiber membrane module according to claim 1. The rectifying plate is disposed so as to wrap the bundle of hollow fiber membranes except in the end face direction of the hollow fiber membrane;
The hollow fiber membrane module of Claim 1 or Claim 2. The hollow fiber membrane bundle is disposed such that the longitudinal direction of the hollow fiber membrane is substantially vertical;
The spout portion is configured to spout a gas that creates the liquid flow such that the plurality of hollow fiber membranes maintain a substantially vertical state;
The hollow fiber membrane module of any one of Claim 1 thru | or 3.

Images