Aeration equipment

Abstract

To provide an air diffuser capable of reducing the time and effort of installation work to attach the membrane to the support.SOLUTION: A membrane type air diffuser 10 includes a membrane 17 formed in the form of a tube having a hollow insert, a support 18 inserted into the insert of the membrane 17 and a gas supply 19. The membrane 17 has a first sheet member 21 with a plurality of slits for releasing air bubbles 4, the support 18 has a gas supply part 23 formed between the outer surface and the inner surface of the first sheet member 21, the gas supply part 23 is provided between the two ends of the membrane 17 in the longitudinal direction A, a ventilation flow path 46 is connected to the gas distribution part 23 from inside the air supply pipe 12, and the membrane 17, the support 18, the gas supply part 19 and the air supply pipe 12 are connected by a connecting member 51.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an aeration system having a membrane type aeration device that emits air bubbles into a liquid and an air supply pipe that supplies gas to the membrane type aeration device. [Background technology]

[0002] Conventionally, an example of this type of aeration equipment is one that has a membrane type aeration device 203 that emits a large number of air bubbles 202 into the water to be treated 201 in a tank 200, and an air supply pipe 208 that supplies air 210 to the membrane type aeration device 203, as shown in FIG.

[0003] The membrane type air diffuser 203 includes membranes 204a and 204b formed in a tubular shape, a support tube 205 inserted into the membranes 204a and 204b, and an air supply unit 206.

[0004] Each end of the membranes 204a, 204b is fixed watertight to the support tube 205 by fasteners 207 such as ring-shaped bands. The support tube 205 is connected to an air supply tube 208. The air supply unit 206 has an air flow passage 209 that communicates from the air supply tube 208 to between the inner circumference of the membranes 204a, 204b and the outer circumference of the support tube 205.

[0005] A plurality of slits 211 are formed in each membrane 204a, 204b for releasing to the outside air 210 supplied from the air supply pipe 208 through the air passage 209 of the air supply section 206 between the inner circumference of the membranes 204a, 204b and the outer circumference of the support tube 205.

[0006] Two membranes 204a and two membranes 204b are attached to one support tube 205, and an air supply unit 206 is provided between one membrane 204a and the other membrane 204b.

[0007] According to this, air 210 is supplied from the air supply pipe 208 through the air flow path 209 of the air supply section 206 to between the inner circumference of the membranes 204a, 204b and the outer circumference of the support tube 205, causing the membranes 204a, 204b to expand, and the air 210 is released into the treated water 201 as air bubbles 202 from the slits 211 of each membrane 204a, 204b.

[0008] The above-mentioned aeration equipment 212 is described in, for example, Patent Document 1 below. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent Publication No. 2005-81203 Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the above-mentioned conventional type, two membranes 204a, 204b are provided for one support tube 205, which means that twice the number of membranes 204a, 204b as there are support tubes 205 are required, and this creates a problem in that when assembling the aeration equipment 212, the installation work of attaching the membranes 204a, 204b to the support tube 205 is time-consuming.

[0011] An object of the present invention is to provide an aeration system that can reduce the labor required for installing a membrane. [Means for solving the problem]

[0012] In order to achieve the above object, the first invention is an aeration system having a membrane type aeration device that emits air bubbles into a liquid and an air supply pipe that supplies gas to the membrane type aeration device, The membrane type air diffuser includes a membrane formed in a tube shape having a hollow insertion portion, a support inserted into the insertion portion of the membrane, and a gas supply portion, The membrane has a first sheet member having a plurality of slits formed therein for releasing air bubbles; a gas flow section is formed between an outer surface of the support and an inner surface of the first sheet member of the membrane; the gas supply section is provided between both ends of the membrane in a longitudinal direction, and has an air passage communicating from the air supply pipe to the gas flow section; The membrane, the support, the gas supply unit, and the air supply pipe are connected by a connecting member, The connecting member has an insertion portion that is inserted into the through holes formed in the membrane, the support, the gas supply section, and the air supply pipe, respectively, a first engagement portion provided at one end of the insertion portion and engaging with the inner surface of the air supply pipe, and a second engagement portion provided at the other end of the insertion portion and engaging with the support.

[0013] According to this, the gas for diffusion is supplied from inside the air supply pipe through the air passage of the gas supply part to the gas flow part, and is then released to the outside through the slits of the first sheet member of the membrane through the gas flow part, causing a large number of air bubbles to be released into the liquid from the membrane type air diffuser.

[0014] In addition, the gas supply section is provided between both longitudinal ends of the membrane, and has an air flow path connecting the air supply pipe to the gas flow section, so that one membrane is provided for one support. As a result, only the same number of membranes as the number of supports are required, which reduces the effort required for attaching the membranes to the supports when assembling the air diffusion equipment.

[0015] In the air diffusion equipment according to the second aspect of the present invention, the membrane has a bag-shaped portion formed into a bag shape by joining a first sheet member and a second sheet member together as a gas flow portion, The first sheet member constitutes an outer peripheral surface of the bag-shaped portion, the second sheet member constitutes an inner circumferential surface of the bag-shaped portion, The ventilation passage of the gas supply portion communicates from the inside of the air supply pipe to the inside of the bag-shaped portion of the membrane.

[0016] According to this, the gas for diffusion is supplied from inside the air supply pipe through the ventilation flow path of the gas supply section to the bag-shaped portion of the membrane, passes through the bag-shaped portion, and is released to the outside from a slit in the first sheet member of the membrane.

[0017] In addition, since the membrane formed in a tube shape has a bag-like portion and gas is supplied into the bag-like portion of the membrane, there is no need to fix the end of the membrane to the outer periphery of the support in a watertight manner with a fastener such as a band after inserting the support into the insertion portion of the membrane. This makes the fastener unnecessary, there is no deterioration of the membrane and a decrease in watertightness at the attachment portion of the fastener, and it is possible to prevent leakage of the gas for diffusion.

[0018] In addition, since the support is inserted into the insertion portion of the membrane, the support prevents the bag-shaped portion of the membrane from expanding toward the inside of the insertion portion. As a result, even if the bag-shaped portion of the membrane tries to expand toward the inside of the insertion portion, it is prevented by the support, and it mainly expands slightly toward the outside of the insertion portion. This reduces the buoyancy acting on the membrane, and the support that fixes the membrane so that it does not float up can be made smaller, and therefore the membrane type air diffuser can be made smaller.

[0019] In the aeration equipment according to the third invention, the support is a tubular member.

[0020] In the fourth aspect of the present invention, the membrane type air diffuser is fixed to the air supply pipe via an adapter, The adapter is sandwiched between the membrane diffuser and the air supply pipe, The gas supply is fitted into the adapter.

[0021] In the air diffusion equipment according to the fifth aspect of the present invention, a seal member that simultaneously seals between the adapter and the air supply pipe and between the adapter and the gas supply unit is held by the adapter.

[0022] With this, it is possible to prevent the diffusion gas from leaking from the air supply pipe to the outside through the gap between the adapter and the air supply pipe, and it is also possible to prevent the diffusion gas from leaking from the air supply pipe to the outside through the gap between the adapter and the gas supply unit, thereby reducing the number of seal members and achieving cost reduction.

[0023] In the air diffusion equipment of the sixth invention, the adapter has a support portion that supports the support body of the membrane type air diffusion device from below via the membrane.

[0024] According to this, the support of the membrane type air diffuser is supported by the support part of the adapter, so that part of the load of the support is received by the air supply pipe via the adapter. As a result, the load of the support is not concentrated on the gas supply part, but is distributed to the gas supply part and the adapter. Therefore, the strength of the gas supply part can be reduced, and the gas supply part can be made smaller and lighter.

[0025] In the air diffusion equipment according to the seventh aspect of the present invention, the membrane type air diffusion device intersects with the air supply pipe at the center in the longitudinal direction.

[0026] According to this, the gas for diffusion passes through the ventilation passage of the gas supply section from inside the air supply pipe, is supplied to the gas flow section evenly from the center of the membrane toward both ends, passes through the gas flow section, and is released to the outside from the slits in the first sheet member of the membrane. Therefore, a large number of bubbles are not released from the membrane in a locally biased manner, but are released evenly from the membrane. Effect of the Invention

[0027] As described above, according to the present invention, the gas supply section is provided between both ends of the membrane in the longitudinal direction and has an air passage communicating from the air supply pipe to the gas flow section, so one membrane is provided for one support. This means that only the same number of membranes as the number of supports are required, which reduces the effort required for attaching the membranes to the supports when assembling the air diffusion equipment. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a perspective view of an air diffusion system according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a side view of a membrane type air diffuser provided in the air diffusion equipment according to the first embodiment. [Diagram 3] FIG. 2 is a cross-sectional view of an end portion of the membrane type air diffuser according to the first embodiment. [Figure 4] FIG. 2 is a perspective view of the membrane and the support tube of the membrane type air diffuser of the first embodiment. [Diagram 5] FIG. 2 is a partially cutaway plan view of the membrane of the membrane type air diffuser of the first embodiment. [Figure 6] FIG. 2 is a partially cutaway bottom view of the membrane of the membrane-type air diffuser of the first embodiment. [Figure 7] FIG. 4 is a cross-sectional view of a support tube of the membrane type air diffuser according to the first embodiment. [Figure 8] FIG. 2 is a cross-sectional view of the connecting portion between the membrane type air diffuser and the air supply pipe of the air diffusion equipment according to the first embodiment. [Figure 9] 9 is a view taken along the arrow XX in FIG. 8. [Figure 10] FIG. 2 is a perspective view of a gas supply nozzle of the membrane type air diffuser according to the first embodiment. [Figure 11] 11 is a view taken along the arrow XX in FIG. [Figure 12] 11 is a view taken along the arrow YY in FIG. 10. [Figure 13] FIG. 2 is a partially cutaway plan view of the gas supply nozzle of the membrane type air diffuser according to the first embodiment. [Figure 14] FIG. 2 is a partially cutaway bottom view of the gas supply nozzle of the membrane type air diffuser according to the first embodiment. [Figure 15] FIG. 2 is a perspective view of the upper side of the adapter of the air diffusion equipment according to the first embodiment. [Figure 16] FIG. 2 is a perspective view of the lower side of the adapter of the air diffusion equipment according to the first embodiment. [Figure 17] FIG. 13 is a disassembled view of the adapter, air supply pipe, and gas supply nozzle of the aeration equipment. [Figure 18] FIG. 2 is a partially enlarged cross-sectional view of the connection between the membrane type air diffuser and the air supply pipe of the air diffusion equipment according to the first embodiment. [Figure 19] FIG. 2 is a diagram showing the steps of a method for manufacturing the membrane of the membrane-type air diffuser according to the first embodiment. [Figure 20] FIG. 2 is a diagram showing the steps of a method for manufacturing the membrane of the membrane-type air diffuser according to the first embodiment. [Figure 21] FIG. 11 is a cross-sectional view of a connecting portion between a membrane type air diffuser and an air supply pipe in an air diffusion system according to a second embodiment of the present invention. [Figure 22] FIG. 1 is a diagram of a conventional membrane type air diffuser. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0030] (First embodiment) In the first embodiment, as shown in Fig. 1, reference numeral 1 denotes an aeration system provided in an aerobic tank (not shown) installed in, for example, a sewage treatment plant. The aeration system 1 is immersed in water to be treated 3 (an example of a liquid) consisting of activated sludge in the tank, and includes a plurality of membrane type aeration devices 10 that emit air bubbles 4 into the water to be treated 3, an air supply pipe 12 that supplies air 11 (an example of a gas for aeration) to each membrane type aeration device 10, an adapter 14 (see Fig. 8) that fixes the membrane type aeration device 10 to the air supply pipe 12, and a blower 15 that supplies air 11 to the air supply pipe 12 from outside the tank.

[0031] As shown in Figures 2 to 6, the membrane type air diffuser 10 has a membrane 17 formed in a tubular (cylindrical) shape with a hollow insertion portion 16 in the center, a support tube 18 (an example of a support) inserted into the insertion portion 16 of the membrane 17, and a gas supply nozzle 19 (an example of a gas supply portion).

[0032] The membrane 17 has a bag-shaped portion 23 formed into a bag shape by welding two front and back sheet members 21, 22. The front-side sheet member 21 (an example of a first sheet member) and the back-side sheet member 22 (an example of a second sheet member) are made of a soft elastic synthetic resin, and the front-side sheet member 21 forms the outer peripheral surface of the bag-shaped portion 23, while the back-side sheet member 22 forms the inner peripheral surface of the bag-shaped portion 23.

[0033] The bag-shaped portion 23 is an example of a gas flow portion formed between the outer circumferential surface of the support tube 18 and the inner circumferential surface of the sheet member 21 on the front side of the membrane 17 .

[0034] A circular first opening 24 is formed in the central portion and upper portion of the membrane 17 in the longitudinal direction A. The insertion portion 16 penetrates both ends of the membrane 17, and the insertion portion 16 and the upper portion of the membrane 17 communicate with each other via the first opening 24.

[0035] 8, 9, and 19, a circular first through hole 26 and a second through hole 27 (an example of a through hole) are formed in the central and lower part of the membrane 17 in the longitudinal direction A. Of these, the first through hole 26 is formed in the sheet member 21 on the front side. The second through hole 27 has a smaller diameter than the first through hole 26 and is formed in the sheet member 22 on the back side. The center of the first through hole 26 and the center of the second through hole 27 are coaxial.

[0036] 4 to 6, both sheet members 21, 22 are welded at welded portions 29. These welded portions 29 include end welded portions 29a formed around the entire periphery at both ends of membrane 17, a central welded portion 29b formed around first opening 24, and a longitudinal welded portion 29c formed between end welded portions 29a and central welded portion 29b.

[0037] A large number of slits 30 are formed in the sheet member 21 on the front side for discharging the air 11 supplied from the gas supply nozzle 19 into the bag-shaped portion 23 to the outside. As shown by the imaginary lines in Fig. 6, a non-formed region 31 where no slits 30 are formed is provided in the lower part of the sheet member 21 on the front side, and the slits 30 are formed in the region other than the non-formed region 31 and the welded portion 29.

[0038] In addition, in drawings such as Figure 2, the slit 30 is drawn in an oval shape to make it easier to see, but in reality, the slit 30 is a slit that is closed when air diffusion is not occurring and is slightly open when air diffusion is occurring.

[0039] 4 and 7, the support tube 18 is a circular tube made of resin with both ends open, and a circular second opening 33 is formed in the center and upper part in the longitudinal direction A of the support tube 18. As shown in Figures 8 and 9, when the support tube 18 is inserted into the insertion part 16 of the membrane 17, the position of the first opening 24 of the membrane 17 and the position of the second opening 33 of the support tube 18 coincide with each other.

[0040] 7, a bolt insertion hole 34 (an example of a through hole) is formed in the central lower portion of the support tube 18 in the longitudinal direction A. As shown in Figs. 8 and 9, the position of the bolt insertion hole 34 in the support tube 18 and the center position of the second through hole 27 in the sheet member 22 on the back side of the membrane 17 coincide with each other.

[0041] 2, 6, and 8 to 14, the gas supply nozzle 19 is provided at the center of the membrane 17 in the longitudinal direction A, and has a circular tubular portion 37, a flange portion 38, and a top plate portion 39. The tubular portion 37 is inserted into the first through-hole 26 (see FIG. 19) of the sheet member 21 on the front side of the membrane 17, and protrudes below the membrane 17. The lower end of the tubular portion 37 is formed with a pair of cutout portions 41 and an inlet 42 that opens into the air supply pipe 12.

[0042] The flange 38 is formed at the upper end of the tube portion 37 and projects outward in the radial direction of the tube portion 37, and enters the bag-shaped portion 23 of the membrane 17, as shown in Figures 8 and 9. A plurality of outlet ports 43 that open into the bag-shaped portion 23 are formed on the outer circumferential surface of the flange 38. The entire periphery of the peripheral portion of the first through-hole 26 (see Figure 19) of the front-side sheet member 21 is welded to the underside of the flange 38, whereby the gas supply nozzle 19 is attached to the membrane 17.

[0043] The top plate portion 39 is formed at the upper end of the tubular portion 37, and a bolt insertion hole 45 (an example of a through hole) is formed in the top plate portion 39 so as to penetrate therethrough in the vertical direction.

[0044] An air flow passage 46 communicating with the inlet 42 and the outlet 43 is formed in the gas supply nozzle 19. As a result, the inside of the air supply pipe 12 and the inside of the bag-shaped portion 23 of the membrane 17 communicate with each other via the air flow passage 46 of the gas supply nozzle 19. In addition, a recess 47 curved in an arc shape along the outer circumferential surface of the support tube 18 is formed on the upper surface of the gas supply nozzle 19.

[0045] As shown in Figures 8 and 9, the membrane type air diffuser 10 is fixed to the air supply pipe 12 via an adapter 14. As shown in Figures 15 to 17, the adapter 14 has a rectangular parallelepiped adapter body 50 sandwiched between the membrane type air diffuser 10 and the air supply pipe 12, and a pair of support parts 55 that support the support pipe 18 of the membrane type air diffuser 10 from below via the membrane 17. The support parts 55 are provided at both ends of the adapter body 50 in the longitudinal direction A of the membrane type air diffuser 10.

[0046] The underside of the adapter body 50 is formed with a recess 52 curved in an arc shape along the outer circumferential surface of the air supply pipe 12, and an O-ring fitting portion 56. The adapter body 50 is also formed with a circular first fitting hole 53 penetrating in the up-down direction. The O-ring fitting portion 56 is formed to surround the periphery of the first fitting hole 53.

[0047] As shown in Fig. 1, the air supply pipe 12 is disposed below the membrane type air diffuser 10 and is perpendicular to the membrane type air diffuser 10 at the center in the longitudinal direction A of the membrane type air diffuser 10. As shown in Fig. 17, the upper end of the air supply pipe 12 is formed with a plurality of circular second fitting holes 54 (an example of through holes) that penetrate the air supply pipe 12 from the inside to the outside.

[0048] The position of the first fitting hole 53 of the adapter 14 coincides with the position of the second fitting hole 54 of the air supply pipe 12. As shown in Figures 8, 9 and 17, the cylindrical portion 37 of the gas supply nozzle 19 is fitted from above into the first fitting hole 53 of the adapter 14 and the second fitting hole 54 of the air supply pipe 12, and the lower end portion protrudes into the air supply pipe 12 through the second fitting hole 54.

[0049] As shown in Figures 8, 9, 17 and 18, an O-ring 62 (an example of a sealing member) that simultaneously seals between the underside of the adapter 14 and the outer peripheral surface of the air supply pipe 12, and between the inner peripheral surface of the first fitting hole 53 of the adapter 14 and the outer peripheral surface of the tubular portion 37 of the gas supply nozzle 19, is fitted into the O-ring fitting portion 56 and held by the adapter 14.

[0050] 8 and 9, the air supply pipe 12, the adapter 14, the membrane 17, the support pipe 18 and the gas supply nozzle 19 are connected by a connecting member 51. The connecting member 51 has a T-head bolt 57 and a nut 58.

[0051] The T-head bolt 57 has a bolt body 57a (an example of an insertion portion) and a head 57b (an example of a first engagement portion) provided at one end of the bolt body 57a. The bolt body 57a is inserted from below through the second fitting hole 54 (an example of a through hole) of the air supply pipe 12, the bolt insertion hole 45 (an example of a through hole) of the gas supply nozzle 19, the second through hole 27 (an example of a through hole) of the sheet member 22 on the back side of the membrane 17, and the bolt insertion hole 34 of the support pipe 18, and protrudes into the support pipe 18.

[0052] Further, the head portion 57b is fitted from below into both notches 41 of the cylindrical portion 37 of the gas supply nozzle 19 and engages with the inner peripheral surface of the upper end portion of the air supply pipe 12.

[0053] Nut 58 is an example of a second engagement portion, and is screwed onto the other end of bolt body 57a inside support pipe 18 and engages with the inner circumferential surface of support pipe 18.

[0054] The entire periphery of the second through hole 27 of the rear sheet member 22 is sandwiched between the outer circumferential surface of the support tube 18 and the top plate portion 39 of the gas supply nozzle 19. A cylindrical packing 60 made of an elastic material such as rubber is fitted into the bolt insertion hole 34 of the support tube 18. This prevents a portion of the air 11 supplied from the inside of the air supply pipe 12 through the ventilation flow path 46 of the gas supply nozzle 19 into the bag-shaped portion 23 of the membrane 17 from leaking into the support tube 18 from between the bolt insertion hole 34 and the bolt main body portion 57a.

[0055] The operation of the above configuration will be described below.

[0056] 1, 8 and 9, by driving the blower 15, air 11 is supplied from the blower 15 into the air supply pipe 12, and the air 11 in the air supply pipe 12 flows from the inlet 42 of the gas supply nozzle 19 through the air flow passage 46 and into the bag-shaped portion 23 of the membrane 17 through the outlet 43. This causes the bag-shaped portion 23 to expand, and the air 11 in the bag-shaped portion 23 is released to the outside through the slits 30 in the front sheet member 21, so that a large number of air bubbles 4 are released from the membrane type air diffuser 10 into the water 3 to be treated.

[0057] In addition, the gas supply nozzle 19 is provided between both ends of the membrane 17 in the longitudinal direction A, and has an air flow path 46 that communicates from the air supply pipe 12 to the bag-shaped portion 23 of the membrane 17, so that one membrane 17 is provided for one support pipe 18. As a result, the same number of membranes 17 as the number of support pipes 18 are required, which reduces the effort required for attaching the membranes 17 to the support pipes 18 when assembling the air diffusion equipment 1.

[0058] Furthermore, the membrane 17 formed in a tube shape as described above has a bag-like portion 23, and since the air 11 is supplied into the bag-like portion 23, it is not necessary to fix the end of the membrane 17 watertightly to the outer periphery of the support tube 18 with a fixing device such as a band after the support tube 18 is inserted into the insertion portion 16 of the membrane 17. This makes the fixing device unnecessary, and the membrane 17 does not deteriorate and the watertightness at the attachment portion of the fixing device does not decrease, and leakage of the air 11 can be prevented.

[0059] In addition, since the support tube 18 is inserted into the insertion portion 16 of the membrane 17, the support tube 18 restricts the bag-shaped portion 23 of the membrane 17 from expanding toward the inside of the insertion portion 16 (i.e., the center in the radial direction of the support tube 18). As a result, even if the bag-shaped portion 23 of the membrane 17 tries to expand toward the inside of the insertion portion 16, it is prevented by the support tube 18, and after being prevented by the support tube 18, it mainly expands only toward the outside of the insertion portion 16 (i.e., the outside in the radial direction of the support tube 18). As a result, the buoyancy acting on the membrane 17 is reduced, and the stand (not shown) to which the air supply pipe 12 is fixed can be made smaller and simpler or more simplified to prevent the membrane type air diffuser 10 from floating up.

[0060] 1, the membrane type air diffuser 10 is perpendicular to the air supply pipe 12 at the center in the longitudinal direction A, so that the air 11 is supplied uniformly from the center of the membrane 17 toward both ends into the bag-shaped portion 23 through the air flow passage 46 of the gas supply nozzle 19. Therefore, a large number of air bubbles 4 are released uniformly from the membrane 17, without being released unevenly in a localized area.

[0061] In addition, since the air intake pipe 12 is located below the membrane type aeration device 10, a large number of air bubbles 4 are released into the water 3 to be treated through the slits 30 of the membrane type aeration device 10 without being blocked by the air intake pipe 12.

[0062] 8, 9 and 18, a single O-ring 62 can be used to prevent air 11 from leaking out from inside the air supply pipe 12 through a gap between the lower surface of the adapter 14 and the outer circumferential surface of the air supply pipe 12, and can also prevent air 11 from leaking out from inside the air supply pipe 12 through a gap between the inner circumferential surface of the first fitting hole 53 of the adapter 14 and the outer circumferential surface of the tubular portion 37 of the gas supply nozzle 19. This allows the number of O-rings 62 to be reduced, leading to cost savings.

[0063] 8 and 15, the support pipe 18 of the membrane type air diffuser 10 is supported from below by the support part 55 of the adapter 14, so that part of the load of the support pipe 18 is borne by the air supply pipe 12 via the adapter 14. As a result, the load of the support pipe 18 is not concentrated on the flange part 38 of the gas supply nozzle 19, but is distributed between the flange part 38 of the gas supply nozzle 19 and the support part 55 of the adapter 14. For this reason, the strength of the gas supply nozzle 19 can be reduced, making the gas supply nozzle 19 smaller and lighter.

[0064] A method for manufacturing the membrane 17 of the membrane type air diffuser 10 will be described below.

[0065] First, as shown in FIG. 19 , the tubular portion 37 of the gas supply nozzle 19 is inserted into the first through hole 26 of the front-side sheet member 21 in which a large number of slits 30 are formed, and the peripheral portion of the first through hole 26 is welded to the underside of the flange portion 38 of the gas supply nozzle 19, thereby attaching the gas supply nozzle 19 to the front-side sheet member 21.

[0066] Thereafter, as shown in Fig. 20, an outer periphery 65 (see Fig. 19) of the front sheet member 21 and an outer periphery 66 (see Fig. 19) of the back sheet member 22 are welded to form a rectangular membrane sheet 67 having a bag-shaped portion 23. The dotted portion in Fig. 20 is the welded portion 29 between the front sheet member 21 and the back sheet member 22.

[0067] Then, as shown in FIG. 20, opposing long sides 68 of membrane sheet 67 are joined together to form a tube, thereby forming membrane 17 having a bag-shaped portion 23 inside, an insertion portion 16 in the center, a first opening 24 at the top, and a gas supply nozzle 19 at the bottom, as shown in FIG. 4. In the above first embodiment, a front sheet member 21 and a back sheet member 22 of approximately the same shape are used to form a tubular membrane 17, but the front sheet member 21 may be welded to the back sheet member 22 only in the necessary area to form a bag-shaped portion 23, or the back sheet member 22 may be welded to the front sheet member 21 only in the necessary area to form a bag-shaped portion 23.

[0068] (Second embodiment) In the first embodiment described above, as shown in Figure 8, the membrane 17 has a front sheet member 21 and a back sheet member 22, but in the second embodiment described below, as shown in Figure 21, the membrane 17 only has a front sheet member 21 in which a number of slits 30 are formed, and does not have a back sheet member 22.

[0069] Both ends of the membrane 17 in the longitudinal direction A are fixed watertightly to the outer periphery of the support tube 18 by fasteners such as bands (not shown).

[0070] In addition, a gas flow section 80 is formed between the outer circumferential surface of the support tube 18 and the inner circumferential surface of the sheet member 21 of the membrane 17. The flange portion 38 of the gas supply nozzle 19 fits into the gas flow section 80. The outlet port 43 opens into the gas flow section 80. As a result, the inside of the air supply pipe 12 and the inside of the gas flow section 80 communicate with each other via the air passage 46 of the gas supply nozzle 19. According to this, air 11 in air supply pipe 12 passes through air flow passage 46 from inlet 42 of gas supply nozzle 19 and flows into gas flow section 80 from outlet 43. This causes sheet member 21 of membrane 17 to expand, and air 11 in gas flow section 80 is released to the outside from slits 30, so that a large number of air bubbles 4 are released from membrane type aeration device 10 into water 3 to be treated.

[0071] In each of the above embodiments, air 11 is used as the gas for diffusion, but a gas other than air 11 may be used. [Explanation of symbols]

[0072] 1. Aeration equipment 3. Treated water (liquid) 4. Bubbles 10. Membrane type aeration device 11 Air (gas) 12 Air supply pipe 14 Adapters 16 Insertion section 17 Membrane 18 Support tube (support body) 19 Gas supply nozzle (gas supply section) 21 front sheet member (first sheet member) 22 Back side sheet member (second sheet member) 23 Bag-shaped portion (gas flow portion) 27 Second through hole (through hole) 30 Slit 34 Bolt insertion hole (through hole) 45 Bolt insertion hole (through hole) 46 Ventilation channel 51 Connecting member 54 Second fitting hole (through hole) 55 Support part 57a Bolt body (insertion part) 57b Head (first engaging part) 58 Nut (second engagement part) 62 O-ring (sealing material) 80 Gas flow section A Longitudinal direction

Claims

1. An aeration system having a membrane type aeration device that releases air bubbles into a liquid and an air supply pipe that supplies gas to the membrane type aeration device, The membrane type air diffuser includes a membrane formed in a tube shape having a hollow insertion portion, a support inserted into the insertion portion of the membrane, and a gas supply portion, The membrane has a first sheet member having a plurality of slits formed therein for releasing air bubbles; a gas flow section is formed between an outer surface of the support and an inner surface of the first sheet member of the membrane; the gas supply section is provided between both ends of the membrane in a longitudinal direction, and has an air passage communicating from the air supply pipe to the gas flow section; The membrane, the support, the gas supply unit, and the air supply pipe are connected by a connecting member, The connecting member is an aeration equipment characterized in that it has an insertion portion that is inserted into through holes formed in the membrane, the support body, the gas supply unit, and the air supply pipe, respectively, a first engagement portion that is provided at one end of the insertion portion and engages with the inner surface of the air supply pipe, and a second engagement portion that is provided at the other end of the insertion portion and engages with the support body.

2. The membrane has a bag-shaped portion formed into a bag shape by a first sheet member and a second sheet member joined to each other as a gas flow portion, The first sheet member constitutes an outer peripheral surface of the bag-shaped portion, the second sheet member constitutes an inner circumferential surface of the bag-shaped portion, 2. The air diffusion system according to claim 1, wherein the air flow passage of the gas supply unit communicates from the inside of the air supply pipe to the inside of the bag-shaped portion of the membrane.

3. 3. The aeration system according to claim 1, wherein the support is a tubular member.

4. The membrane type aeration device is fixed to the air intake pipe via an adapter, The adapter is sandwiched between the membrane diffuser and the air supply pipe, 4. The air diffusion system according to claim 1, wherein the gas supply unit is fitted into the adapter.

5. 5. The air diffusion system according to claim 4, wherein a seal member is held by the adapter for simultaneously sealing between the adapter and the air supply pipe and between the adapter and the gas supply section.

6. 6. The air diffusion system according to claim 4, wherein the adapter has a support portion for supporting the support body of the membrane type air diffusion device from below via the membrane.

7. 7. The air diffusion system according to claim 1, wherein the membrane type air diffuser intersects with the air supply pipe at a central portion in a longitudinal direction.

Images