JP2006007223A - Dipped type membrane cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dipped type membrane cartridge with enhanced durability against aeration. <P>SOLUTION: This dipped type membrane cartridge has a resin filter plate 41 and a filter membrane 44 disposed by covering a surface of the filter plate 41 and a fixed part formed by welding the filter membrane 44 to a welding margin formed along the filter plate 41. The filter membrane 44 is formed by forming an organic membrane 44b on front and rear sides of a nonwoven fabric membrane support material 44a, and a welding layer F is formed so as to reach the front layer of the welding face side of the membrane support 44a at the fixed part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a submerged membrane cartridge and relates to the technology of a membrane cartridge mounted on a solid-liquid separation device used in domestic wastewater treatment, industrial wastewater treatment, or the like.

  As a conventional solid-liquid separator, for example, there is a submerged membrane separator as shown in FIG. In FIG. 15, the membrane separation device 21 is configured by arranging a plurality of flat plate membrane cartridges 22 and an air diffuser 23 for jetting membrane surface cleaning gas from below the case 24. The case 24 is divided into a membrane case 25 and an air diffuser case 26, and is formed so that the entire amount of the film surface cleaning gas ejected from the air diffuser 23 enters the film case 25.

  The membrane cartridge 22 has filtration membranes 22B disposed on both surfaces of a filter plate 22A made of ABS resin, and the filtration membrane 22B is fused to the filter plate 22A by ultrasonic welding (welding) at the water stop portion S at the peripheral edge thereof. Is. A permeate channel is formed between the filter plate 22A and the filter membrane 22B and inside the filter plate 22A, and a permeate outlet 22C communicating with the permeate channel is formed at the upper edge of the filter plate 22A. Yes.

  Each membrane cartridge 22 communicates with a water collection pipe 28 via a tube 27 connected to the permeate outlet 22C, and a permeate discharge pipe 29 for leading the membrane permeate is connected to the water collection pipe 28.

  When the membrane separation device 21 is used in an activated sludge treatment facility, the membrane separation device 21 is immersed in the activated sludge mixed solution inside the aeration tank, and aeration air is ejected from the aeration device 23 in the raw water. Organic matter and nitrogen are treated with activated sludge.

  The activated sludge mixed liquid is gravity filtered by the membrane cartridge 22 with the water head in the tank as the driving pressure (the suction filtration is also possible by inserting a suction pump in the permeate outlet pipe 29), and the membrane of the membrane cartridge 22 The permeated liquid that has passed through the surface is led out of the tank through the permeated liquid outlet pipe 29 as treated water.

  At this time, the bubbles of the aerated air ejected from the diffuser 23 and the upward flow generated thereby flow through the narrow flow path (width of 5 to 10 mm) between the membrane cartridges 22 adjacent to each other. The membrane surface of the cartridge 22 is washed to suppress a decrease in separation function, thereby preventing the membrane separation device 21 from malfunctioning.

As described above, when the membrane separation device 21 is used, the membrane cartridge 22 is exposed to the upward flow caused by the aeration air, so that the region surrounded by the water-stopping portion S and the peripheral portion of the filtration membrane 22B vibrate, resulting in fatigue. There is a possibility that the filtration membrane 22B breaks at the water stop portion S.
For this reason, as shown in FIG. 16, in the peripheral fixing part B formed intermittently along the peripheral part of the filtration membrane 22B, there is one that auxiliaryly fixes the filtration membrane 22B to the filter plate 22A.
Japanese Patent Laid-Open No. 7-24270

  An example of the ultrasonic welding (welding) method is a rotary welding (welding) method. As shown in FIG. 17, the filter membrane 22B is disposed so as to cover the surface of the filter plate 22A, and the rotary horn 31 is rotated while pressing the filter membrane 22B against the filter plate 22A by the rotary horn 31. The filter membrane 22B and the filter plate 22A are fused by the output ultrasonic wave to form the water stop portion S and the auxiliary fixing portion B.

  However, in the rotary welding (welding) method, as shown in FIG. 18, the filter plate 22A melts in the water-stopping portion S and is recessed into a groove shape, and the filtration membrane 22B is fused in a state of biting into the filter plate 22A. The filtration membrane 22B is painful during welding (welding), and fatigue failure tends to occur.

  Another example of the ultrasonic welding (welding) method is an up-down method. As shown in FIGS. 19 to 21, a linear melting allowance 32 and a belt-like auxiliary melting allowance 33 for forming the water stop portion S are previously formed on the surface of the filter plate 22A so as to protrude from the surface. In addition, the filtration membrane 22B is disposed so as to cover the melting allowance 32 and the auxiliary melting allowance 33, and the up / down horn 34 is pressed onto the melting allowance 32 and the auxiliary melting allowance 33 from above the filtration membrane 22B.

  The up / down horn 34 has a pattern portion (knurl) 34a on the lower surface facing the filtration membrane 22B, and the pattern portion 34a has a shape in which regular square pyramids having a height of 0.3 mm are arranged at a pitch of 0.6 mm. Yes.

  By the ultrasonic vibration output from the up / down horn 34, the filtration membrane 22B is fused to the filter plate 22A at the melting allowance 32 and the auxiliary melting allowance 33 to form the linear water stop portion S and the auxiliary fixing portion B. It is.

  By the way, the filtration membrane 22B is formed by forming a membrane with an organic material on the front and back of the nonwoven fabric forming the base material, and the mechanical strength is ensured by the nonwoven fabric. For this reason, in the above-described method, the filtration membrane 22B is locally pressed at the site corresponding to the pattern portion 34a of the up / down horn 34, and the nonwoven fabric fibers are easily broken due to excessive energy concentration at the site. The mechanical strength is impaired.

  The present invention solves the above-described problems, and an object of the present invention is to provide an immersion type membrane cartridge with improved durability against aeration.

  In order to solve the above-mentioned problems, the immersion membrane cartridge of the present invention has a filter plate made of resin and a filter membrane arranged so as to cover the surface of the filter plate, and in the melting allowance formed along the filter plate, the filter membrane A fusion part is formed by forming an organic film on the front and back of the membrane support material made of nonwoven fabric, and the fusion membrane reaches the surface layer on the welding surface side of the membrane support material. A layer is formed.

  In the above-described configuration, the immersion type membrane cartridge is used in a state where it is immersed in a reaction vessel and aerated from below. In this state, since the upward flow of the gas-liquid / solid mixed phase derived from aeration flows along the film surface, the vibration derived from the gas / liquid / solid mixed phase flow acts on the submerged membrane cartridge. In addition, the usage environment of the immersion membrane cartridge in the reaction tank changes depending on the shape of the reaction tank, the properties of the liquid to be treated stored in the reaction tank, seasonal fluctuation factors, etc. Unexpected external force may be applied.

  In the present invention, by forming a fusion layer that reaches the surface layer on the welding surface side of the membrane support material in the fixing part, even when the filtration membrane peels off at the fixing part due to unexpected external force and vibration fatigue, Since the membrane is peeled off from the fixing portion without causing breakage of the membrane support material, the membrane can be easily repaired and the life of the membrane cartridge can be extended.

  However, if a fusion layer is formed that reaches the membrane support material of the filtration membrane deeply at the fixed part and the filtration membrane is strongly fused so that it does not peel from the filter plate, more heat energy than necessary is generated at the fusion site. As a result, the membrane support material of the filtration membrane is deteriorated, the life of the membrane cartridge is reduced, and the filtration membrane is broken at the fixed portion. Moreover, when the fusion | melting layer which reaches | attains the membrane support material of a filtration membrane shallowly in a fixed part is formed, a filtration membrane peels in a membrane support material and cannot be repaired.

The immersion membrane cartridge of the present invention is characterized in that the melting allowance projects from the surface of the filter plate and is molded along the peripheral edge of the filter plate.
Moreover, the immersion type membrane cartridge of the present invention is characterized in that the fixing part is formed by fusing the filtration membrane to the filter plate over the entire circumference.

  In the immersion type membrane cartridge of the present invention, the fixed part protrudes from the surface of the filter plate, and the filter membrane is fused at a plurality of melting allowances formed in a multiple manner along the peripheral edge of the filter plate. Features.

  Further, in the immersion type membrane cartridge of the present invention, the fixing portion forms an inner fixing portion that holds the filtration membrane in a tension state at the inner melting allowance, and has a water stop function over the entire circumference of the filtration membrane at the central melting allowance. A water stop portion to be secured is formed, and an outer fixing portion for fixing the periphery of the filtration membrane to the filter plate is formed by an outer melting allowance.

  With this configuration, the inner fixing part that holds the filtration membrane in a tension state and the outer fixing part that fixes the periphery of the filtration membrane to the filter plate have sufficient strength against the external force that acts on the filtration membrane in normal use. The external force is received by the inner fixing portion and the outer fixing portion so that the external force does not reach the water stopping portion, and damage to the water stopping portion can be prevented.

  In this way, the inner fixing portion and the outer fixing portion protect the external force, so that even if the filtration membrane is peeled off by the inner fixing portion or the outer fixing portion due to vibration fatigue and unexpected external force, the water stopping portion Are not peeled off at the same time, and the filtration performance of the submerged membrane cartridge can be prevented from being damaged in an unexpected situation, and the durability of the submerged membrane cartridge against aeration is increased.

  In addition, when peeling occurs at the inner fixing part or the outer fixing part, the inner fixing part or the outer fixing part is repaired to recover its function as a protective body and prevent the water-stopping part from peeling off, The life of the mold membrane cartridge can be extended.

  As described above, according to the present invention, when the fusion membrane reaching the surface layer of the membrane support material of the filtration membrane is formed in the fixed portion, the filtration membrane peels off at the fixed portion due to vibration fatigue and unexpected external force. However, since the filtration membrane peels off from the fixed portion without causing breakage of the membrane support material, it can be easily repaired. When peeling occurs on the inner fixing part or outer fixing part, the inner fixing part or outer fixing part is repaired to restore its protective function and prevent the water-stopping part from peeling off. The life of the cartridge can be extended. By fusing the filtration membrane to the filter plate over the entire circumference in the inner fixing part, the water stopping part, and the outer fixing part, multiple water stopping functions can be ensured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The submerged membrane cartridge in the present embodiment is used for the submerged membrane separator, and the basic structure of the submerged membrane separator is the same as that described above with reference to FIG. The same reference numerals are given to the members and the description is omitted.

Below, the manufacturing method of the immersion type membrane cartridge in this Embodiment is demonstrated with reference to FIGS.
As shown in FIG. 2, the filter plate 41 of the submerged membrane cartridge 40 is made of ABS resin, and has a shape of, for example, 490 mm in width, 1000 mm in length, and 6 mm in thickness. A linear melt allowance 42b located at the center and a mesh-like melt allowance 43 of a predetermined width located outside are projected from the front and back surfaces of the filter plate 41 and formed integrally over the entire periphery along the peripheral edge of the filter plate 41. is doing.

  The linear melting allowances 42a and 42b have a height of 0.4 to 0.6 mm. The mesh melting allowance 43 is located at a position corresponding to the periphery of the filtration membrane 44, has a shape that is lower by about 0.1 mm than the linear melting allowances 42a, 42b, and has three broken line trajectories 43a, 43b, 43c. It is a stacked shape.

  As shown in FIG. 3, filtration membranes 44 are arranged on both front and back surfaces of the filter plate 41 so as to cover the linear melting allowances 42 a and 42 b and the mesh melting allowance 43. The filtration membrane 44 is obtained by forming an organic membrane 44b on the front and back of a membrane support material 44a made of a nonwoven fabric.

  As shown in FIG. 4, the filter plate 41 with the filtration membrane 44 is disposed on the jig 45, and the mesh melting allowance 43 on the lower surface of the filter plate 41 is supported by the jig 45 through the filtration membrane 44. In this state, the up / down horn 46 is pressed against the linear melting allowances 42 a and 42 b and the mesh melting allowance 43 from above the filter membrane 44 disposed on the upper surface of the filter plate 41.

The up / down horn 46 vibrates ultrasonically, and the lower surface facing the filtration membrane 44 is a flat surface.
An ultrasonic wave is output from the up / down horn 46 and the filtration membrane 44 is fused at the linear melting allowances 42 a and 42 b and the mesh melting allowance 43. At this time, since the mesh melting allowance 43 is lower than the linear melting allowances 42a and 42b, the filtration membrane 44 is sandwiched between the up / down horn 46 and the linear melting allowances 42a and 42b on the upper surface side of the filter plate 41. Thus, it does not come into contact with the mesh melting allowance 43. Therefore, the filtration membrane 44 and the filter plate 41 are fused in the linear melting allowances 42a and 42b, and a sufficiently strong weld (welding) is performed. In the mesh melting allowance 43, an error in the height dimension is caused. Fusion occurs only at high sites. On the other hand, since the filtration membrane 44 is sandwiched between the jig 45 and the mesh melting allowance 43 on the lower surface side of the filter plate 41, the filtration membrane 44 and the filter plate 41 are fused only at the mesh melting allowance 43. It is possible to perform welding (welding) with sufficient strength. After completion of this fusion, the filter plate 41 with the filtration membrane 44 is reversed and placed again on the jig 45, and the fusion is performed again in the same procedure.

  In this fusion operation, as shown in FIG. 12, a fusion layer F reaching the surface layer on the welding surface side of the membrane support material 44a is formed in the inner fixing portion A, the water stop portion S, and the outer fixing portion C. For this reason, the pressing force (0.2 to 0.6 MPa), amplitude (30 to 60 μm), and oscillation time (0.1 to 0.5 seconds) of the up / down horn 46 are set.

  In this way, using the flat up / down horn 46, the inner fixed portion A is obtained by fusing the filtration membrane 44 with the linear melting allowances 42 a and 42 b and the mesh melting allowance 43 protruding from the surface of the filter plate 41. By forming the water stop portion S and the outer fixing portion C, it is possible to prevent the filtration membrane 44 from being deteriorated due to excessive energy concentration, and to prevent the occurrence of knurled scratches as in the conventional case.

  By the way, the wide network melting allowance 43 tends to be uneven in height, and when the linear melting allowances 42a and 42b and the mesh melting allowance 43 are simultaneously pressed by the flat surface of the up / down horn 46, the mesh melting allowance 43 The fusion layer F of the outer fixing part C becomes insufficient and becomes discontinuous, or the inner fixing part A and the fusion layer F of the water stop part S in the linear fusion allowances 42a and 42b become excessive, and the inner fixing part A, It is difficult to simultaneously form an appropriate fusion layer F on the water stop portion S and the outer fixing portion C.

  However, the heights of the linear melting allowances 42a and 42b and the mesh melting allowance 43 are different from each other, and by separately fusing on the front and back of the filter plate 41, the melting operation according to the characteristics of each melting allowance is performed. An appropriate fusion layer F can be formed on the fixing portion A, the water stopping portion S, and the outer fixing portion C.

  As shown in FIG. 1, a linear inner fixing portion A is formed in the inner linear melting allowance 42 a and a water stop portion S is formed in the central linear melting allowance 42 b by the above-described fusion operation. The effective filtration region of the filtration membrane 44 surrounded by the inner fixing part A and the water stop part S after the fusion is kept in a tension state.

  The outer fixing portion C formed in the mesh melting allowance 43 intermittently fixes the periphery of the filtration membrane 44 to the filter plate 41. The inner fixing portion A, the water stopping portion S, and the outer fixing portion C have a shape in which the trajectory is continuous over the entire circumference of the filtration membrane 44, and the filtration membrane 44 is fused to the filter plate 41 over the entire circumference, thereby providing a water stopping function. Demonstrate. In particular, the outer fixing portion C is sealed in multiples by three trajectories 43a, 43b, 43c. In addition, the outer side fixing | fixed part C does not necessarily need to have a water stop function, and it is also possible to form the locus | trajectory in a discontinuous thing.

  Hereinafter, the operation of the above-described configuration will be described. The flat membrane-like membrane cartridge 40 is mounted on the case 24 of the membrane separation device 21, immersed in an aeration tank, and used in a state of aeration from below. In this state of use, the upward flow of the gas-liquid solid mixed phase derived from aeration flows along the film surface, so that vibrations derived from the gas liquid solid mixed phase flow act on the submerged membrane cartridge 40. In particular, a high load acts on the submerged membrane cartridge 40 due to aeration when the filtration is stopped, and the repeated stress due to this load is concentrated in the vicinity of the boundary between the filtration membrane 44 and the filter plate 41 in the inner fixing portion A.

  The use environment of the submerged membrane cartridge 40 in the aeration tank changes depending on the shape of the aeration tank, the properties of the liquid to be treated stored in the aeration tank, seasonal fluctuation factors, and the like. An unexpected external force may act on 40.

  The inner fixing portion A that holds the filtration membrane 44 in a tensioned state and the outer fixing portion C that fixes the periphery of the filtration membrane 44 to the filter plate 41 are sufficient with respect to an external force that acts on the filtration membrane 44 in a normal use state. By having the strength and receiving the external force at the inner fixing portion A and the outer fixing portion C, the external force does not reach the water stopping portion S, and the water stopping portion S can be prevented from being damaged.

  As described above, when the inner fixing portion A and the outer fixing portion C form a protective body against external force, the filtration membrane 44 is peeled off by the inner fixing portion A or the outer fixing portion C due to vibration fatigue and unexpected external force. However, the water stop portion S does not peel off at the same time, and the filtration ability of the submerged membrane cartridge 40 can be prevented from being damaged in an unexpected situation, and the durability of the submerged membrane cartridge 40 against aeration is increased.

  When peeling occurs in the inner fixing part A or the outer fixing part C, the inner fixing part A or the outer fixing part C is repaired to recover its function as a protective body and prevent the water-stopping part S from peeling off. In addition, the life of the submerged membrane cartridge 40 can be extended.

  Since the outer fixed portion C has a mesh shape, the peripheral edge of the filtration membrane 44 is welded (welded) at the outer fixed portion C having a predetermined width. Therefore, a dimensional error between the filtration membrane 44 and the filter plate 41 is caused at the outer fixed portion C. Can be absorbed.

In the submerged membrane cartridge 40, the inner fixing part A, the water stopping part S, and the outer fixing part C exhibit a water stopping function, so that it is possible to ensure multiple water stopping functions.
By forming the fusion layer F reaching the surface layer of the membrane support material 44a of the filtration membrane 44 in the inner fixing portion A, the water stopping portion S, and the outer fixing portion C by fusion, the filtration membrane 44 is caused by vibration fatigue and unexpected external force. Even when the membrane is peeled off at the inner fixing portion A and the outer fixing portion C, the filtration membrane 44 does not break at the water stopping portion S, and the inner fixing portion A or the outer side does not break without breaking the membrane support material 44a. It peels from the fixing part C and maintains its function as a film. For this reason, it is possible to extend the life of the membrane cartridge 40 by repairing the inner fixing portion A or the outer fixing portion C that has been peeled off during inspection or the like.

  A peel test for the welding (welding) strength will be described below. As shown in FIG. 5, this peel test is performed by pulling a filtration membrane 44 (test piece cut to a predetermined width) fused to the filter plate 41 perpendicularly to the filter plate 41.

  As shown in FIG. 6, when the fusion layer F that reaches the membrane support material 44 a of the filtration membrane 44 is formed in the inner fixing part A, the water stopping part S, and the outer fixing part C by fusion, As shown, the filtration membrane 44 breaks at the inner fixed portion A. In this case, as clearly shown in the relationship diagram between the tensile strength and the tensile time shown in FIG. 8, the peak of strength is high, but it suddenly breaks.

  In this way, if the filtration membrane 44 is strongly fused so as not to peel from the filter plate 41, thermal energy more than necessary is generated at the fusion site, and the membrane support material 44a of the filtration membrane 44 is deteriorated. As a result, the life of the cartridge 22 is reduced.

  As shown in FIG. 9, when the fusion layer F that reaches the membrane support material 44a of the filtration membrane 44 shallowly is formed in the inner fixing part A, the water stop part S, and the outer fixing part C by fusion, As shown, the filtration membrane 44 peels off at the membrane support material 44a. In this case, as is clear from the relationship between the tensile strength and the pulling time shown in FIG. 11, the strength peak is lower than that of the strongly fused portion, and the water stopping portion S after the inner fixing portion A is broken. Since the outer fixing portion C is continuously damaged and peels off at the membrane support material 44a, it cannot be repaired.

  As shown in FIG. 12, when the fusion layer F that reaches the surface layer on the welding surface side of the membrane support material 44a of the filtration membrane 44 is formed in the inner fixing portion A, the water stopping portion S, and the outer fixing portion C by fusion. As shown in FIG. 13, the filtration membrane 44 peels off at the surface layer on the welding surface side of the membrane support material 44a. In this case, as clearly shown in the relationship diagram between the tensile strength and the pulling time shown in FIG. 14, the peak of strength is lower than that of the strongly fused portion, but the water stoppage even after the inner fixing portion A peels off. Since the predetermined fusion strength is maintained in the portion S, the life of the immersion membrane cartridge 40 is extended.

  As described above, according to the present invention, with respect to the external force acting on the filtration membrane in a normal use state, the inner fixing portion that holds the filtration membrane in a tensioned state, and the outer fixing that fixes the periphery of the filtration membrane to the filter plate When the part forms a protective body, external force does not reach the water stop part, and damage to the water stop part can be prevented. Even if the filtration membrane peels off at the inner and outer fixed parts due to vibration fatigue and unforeseen external forces, the water stop part does not peel off at the same time, and the durability of the submerged membrane cartridge against aeration can be improved. it can. When peeling occurs on the inner fixing part or outer fixing part, the inner fixing part or outer fixing part is repaired to restore its protective function and prevent the water-stopping part from peeling off. The life of the cartridge can be extended. By forming the outer fixing portion in a mesh shape, a dimensional error between the filtration membrane and the filter plate can be absorbed in the outer fixing portion. By fusing the filtration membrane to the filter plate over the entire circumference in the inner fixing part, the water stopping part, and the outer fixing part, multiple water stopping functions can be ensured. By forming a fusion layer that reaches the surface layer of the membrane support material of the filtration membrane at the inner fixed portion, the water stop portion, and the outer fixed portion, the filtration membrane can be connected to the inner fixed portion and the outer fixed portion without breaking the membrane support material. Since it peels off, it can be easily repaired.

It is a schematic diagram which shows the film | membrane cartridge in embodiment of this invention. It is a schematic diagram which shows the filter plate in the same embodiment. It is a schematic diagram which shows the manufacture procedure of the film | membrane cartridge in the same embodiment. It is a schematic diagram which shows the manufacturing method of the film | membrane cartridge in the embodiment. It is a schematic diagram which shows the test method of welding strength. It is a schematic diagram which shows the strong welding state of a filtration membrane. It is a schematic diagram which shows the fracture | rupture form of the filtration membrane in a strong welding state. It is a correlation diagram of tensile strength and tension time in a strong welding state. It is a schematic diagram which shows the slightly strong welding state of a filtration membrane. It is a schematic diagram which shows the peeling form of the filtration membrane in a slightly strong welding state. It is a correlation diagram of the tensile strength and the tension time in a slightly strong welding state. It is a schematic diagram which shows the ideal welding state of a filtration membrane. It is a schematic diagram which shows the peeling form of the filtration membrane in an ideal welding state. FIG. 5 is a correlation diagram between tensile strength and tension time in an ideal welding state. It is a perspective view which shows the conventional membrane separator. It is a schematic diagram which shows the conventional membrane cartridge. It is a schematic diagram which shows the manufacturing method of the conventional film | membrane cartridge. It is sectional drawing of the conventional film | membrane cartridge. It is a schematic diagram which shows the manufacturing method of the conventional film | membrane cartridge. It is a schematic diagram which shows the conventional up-down horn. It is a schematic diagram which shows the conventional membrane cartridge.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Membrane separator 23 Air diffuser 24 Case 25 Membrane case 26 Air diffuser case 27 Tube 28 Water collecting pipe 29 Permeate outlet pipe 40 Immersion type membrane cartridge 41 Filter plate 42a Linear melting allowance 42b Linear melting allowance 43 Network melting allowance 44 Filtration Membrane 44a Membrane Support Material 44b Membrane 45 Jig 46 Up / Down Horn A Inner Fixed Portion S Water Stopping Portion B Outer Fixed Portion F Fused Layer

Claims (5)

It has a filter plate made of resin and a filter membrane arranged so as to cover the surface of the filter plate, and forms a fixed part formed by fusing the filter membrane in the melting allowance formed along the filter plate, and the filter membrane is made of nonwoven fabric. An immersion type membrane cartridge, wherein an organic film is formed on the front and back of the membrane support material to be formed, and a fusion layer reaching the surface layer on the welding surface side of the membrane support material is formed in the fixing portion. The immersion membrane cartridge according to claim 1, wherein the melting allowance projects from the surface of the filter plate and is molded along the peripheral edge of the filter plate. The submerged membrane cartridge according to claim 1 or 2, wherein the fixing part is formed by fusing the filtration membrane to the filter plate over the entire circumference. The fixed part protrudes from the surface of the filter plate and is formed by fusing the filtration membrane at a plurality of melting allowances formed in a multiple manner along the peripheral edge of the filter plate. Immersion type membrane cartridge. The fixing part forms an inner fixing part that holds the filtration membrane in a tension state at the inner melting allowance, and forms a water stopping part that secures a water stopping function over the entire circumference of the filtration membrane at the central melting allowance. The submerged membrane cartridge according to claim 4, wherein an outer fixing portion for fixing the periphery of the filtration membrane to the filter plate is formed by a melting allowance.

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