JP7561600B2 - Membrane type air diffuser, air diffuser equipment, and membrane manufacturing method - Google Patents

Description

The present invention relates to a membrane-type air diffuser that releases air bubbles into a liquid, an air diffuser installation, and a method for manufacturing a membrane.

Conventionally, as shown in FIG. 20, there is a membrane type aeration device of this type that releases a large number of air bubbles 202 into the water to be treated 201 in a tank 200. This membrane type aeration device 203 has a membrane 204 formed in a tubular shape, a support tube 205 inserted into the membrane 204, and an air supply unit 206.

The end of the membrane 204 is fixed watertight to the support tube 205 with a fastener 207 such as a ring-shaped band. The support tube 205 is connected to an air supply tube 208. The air supply section 206 has an air flow passage 209 that connects the air supply tube 208 to the inner circumference of the membrane 204 and the outer circumference of the support tube 205.

The membrane 204 has multiple slits 211 formed therein for releasing to the outside the 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 membrane 204 and the outer circumference of the support pipe 205.

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 membrane 204 and the outer circumference of the support pipe 205, causing the membrane 204 to expand, and the air 210 is released into the water to be treated 201 as air bubbles 202 from the slits 211 of the membrane 204.

The membrane type aeration device 203 described above is described, for example, in Patent Document 1 below.

In addition to the membrane type air diffuser 203 described above, there is a membrane type air diffuser 300, as shown in Figures 21 and 22, in which an air supply nozzle 302 is provided at one end of a bag-shaped body 301 that extends in a long, strip-like shape. The bag-shaped body 301 is made by welding and joining an impermeable sheet-shaped member 303 and a breathable sheet-shaped member 304.

The bag-shaped body 301 is supported by a pair of rod-shaped support members 305, both of which are fixed to a fixing member 306.

According to this, by supplying air 307 from an air supply nozzle 302 into a bag-shaped body 301, the bag-shaped body 301 expands due to the pressure of the air 307, and the air 307 in the bag-shaped body 301 passes through a breathable sheet-like member 304 and is released as air bubbles into the water to be treated in a tank 309. A membrane-type aeration device 300 using such a bag-shaped body 301 is described, for example, in Patent Document 2 below.

JP2005-81203A Patent No. 5404189

However, in the conventional type described above, the membrane type air diffuser 203 shown in Figure 20 requires that the end of the membrane 204 be fixed watertightly to the outer periphery of the support tube 205 with a fastener 207 such as a band. If the membrane 204 deteriorates after many years of use, the watertightness of the attachment part of the fastener 207 decreases, causing a problem that air 210 leaks out.

In addition, in another membrane type air diffuser 300 shown in Figures 21 and 22, the entire bag-shaped body 301 expands greatly due to the pressure of the air 307, so a strong buoyancy is generated in the bag-shaped body 301. This causes the support member 305 and fixing member 306 for fixing the bag-shaped body 301 so that it does not float up to the surface to become larger, which causes a problem that the membrane type air diffuser 300 becomes larger.

The present invention aims to provide a membrane-type aeration device, aeration equipment, and a method for manufacturing a membrane that can prevent leakage of the gas used for aeration and can be made compact.

In order to achieve the above object, the first invention is a membrane type air diffuser that emits air bubbles into a liquid,
A membrane formed in a tubular shape having an insertion portion at its center;
A tubular support member inserted into the membrane insertion portion;
A gas supply unit,
The membrane has, at least in a portion thereof, a bag-shaped portion formed in a bag shape by two sheet members on the front and back sides,
the gas supply unit has an air passage communicating from the outside to the inside of the bag-shaped portion of the membrane;
The sheet material constituting the outer peripheral surface of the bag-shaped portion of the membrane has a plurality of slits formed therein for releasing to the outside the gas supplied into the bag-shaped portion through the ventilation flow path of the gas supply section.

According to this, by operating the membrane type air diffuser, gas is supplied into the bag-shaped portion of the membrane through the air passage of the gas supply unit, causing the bag-shaped portion of the membrane to expand, and the gas for diffusion within the bag-shaped portion is released to the outside through the slits. This causes a large number of air bubbles to be released from the membrane type air diffuser into the liquid.

Here, the membrane formed in a tube shape has a bag-like portion, and since gas is supplied into the bag-like portion of the membrane, there is no need to fix the end of the membrane watertightly to the outer periphery of the support member with a fixing device such as a band after inserting the tubular support member into the insertion portion of the membrane. This eliminates the need for a fixing device, prevents the membrane from deteriorating and reducing the watertightness at the attachment portion of the fixing device, and prevents leakage of the gas for diffusion.

In addition, because a support member is inserted into the insertion portion of the membrane, the support member 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 member, and it mainly expands slightly toward the outside of the insertion portion. This reduces the buoyancy acting on the membrane, and the support member that fixes the membrane so that it does not float up can be made smaller, which in turn makes it possible to make the membrane-type air diffuser more compact.

The second invention is an aeration system having the membrane type aeration device according to the first invention ,
An air supply pipe for supplying gas to the membrane type air diffuser is provided.
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,
The gas supply is fitted into the adapter,
The ventilation passage communicates with the inside of the air supply pipe and the inside of the bag-shaped portion of the membrane.

According to this, the gas for diffusion is supplied from inside the air supply pipe through the air flow passage of the gas supply section into the bag-shaped part of the membrane.

In the third aspect of the present invention, the air diffusion equipment has an adapter provided at the bottom of the membrane type air diffusion device,
The air supply pipe is located below the membrane type air diffuser.

This allows a large number of air bubbles to be released into the liquid from the membrane type air diffuser without being blocked by the air supply pipe.

The fourth invention is a method for manufacturing a membrane of the membrane type air diffuser according to the first invention ,
A membrane sheet having a bag-shaped portion and a rectangular outer shape is formed by two sheet members on the front and back sides,
Two opposing sides of a membrane sheet are joined together to form a tube.

This makes it easy to manufacture a tubular membrane with a bag-shaped portion.

As described above, according to the present invention, there is no need to fix the end of the membrane to the outer circumference of the support member in a watertight manner using a fastener such as a band, which eliminates the need for a fastener, prevents the membrane from deteriorating and reducing the watertightness of the attachment part of the fastener, and prevents gas leakage.

In addition, even if the bag-shaped portion of the membrane tries to expand toward the inside of the insertion section, it is prevented by the support member, and it mainly expands slightly toward the outside of the insertion section, so the buoyancy acting on the membrane is reduced and the support member that fixes the membrane so that it does not float up can be made smaller. This makes it possible to make the membrane-type air diffuser more compact.

1 is a perspective view of an air diffusion system according to a first embodiment of the present invention; FIG. 2 is a side view of a membrane type air diffuser provided in the air diffusion equipment according to the first embodiment. FIG. 2 is a cross-sectional view of an end portion of the membrane type air diffuser according to the first embodiment. FIG. 2 is a perspective view of a membrane and a support member of the membrane type air diffuser of the first embodiment. FIG. 2 is a partially cutaway plan view of the membrane of the membrane type air diffuser of the first embodiment. FIG. 2 is a partially cutaway bottom view of the membrane of the membrane-type air diffuser of the first embodiment. FIG. 4 is a cross-sectional view of a support member of the membrane type air diffuser of the first embodiment. 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. 9 is a view taken along the line XX in FIG. 8. FIG. 2 is a perspective view of a gas supply nozzle of the membrane type air diffuser according to the first embodiment. 11 is a view taken along the line XX in FIG. 10. 11 is a view taken along the line YY in FIG. FIG. 2 is a partially cutaway plan view of the gas supply nozzle of the membrane type air diffuser according to the first embodiment. FIG. 2 is a partially cutaway bottom view of the gas supply nozzle of the membrane type air diffuser according to the first embodiment. FIG. 2 is a perspective view of the upper side of the adapter body of the air diffusion equipment according to the first embodiment. FIG. 2 is a perspective view of the lower side of the adapter body of the air diffusion equipment according to the first embodiment. FIG. 2 is a disassembled view of the adapter body, air supply pipe, and gas supply nozzle of the air diffusion equipment. 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. 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. FIG. 1 is a diagram of a conventional membrane type air diffuser. FIG. 1 is a plan view of another conventional membrane type air diffuser. This is a view taken along the line XX in Figure 21.

The following describes an embodiment of the present invention with reference to the drawings.

(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, etc. 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 diffusing air) 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.

As shown in Figures 2 to 6, the membrane type aeration device 10 has a membrane 17 formed in a tubular (cylindrical) shape with an insertion section 16 in the center, a cylindrical support member 18 inserted into the insertion section 16 of the membrane 17, and a gas supply nozzle 19 (an example of a gas supply section).

The membrane 17 has a bag-shaped portion 23 formed by welding two front and back sheet members 21 and 22. These sheet members 21 and 22 are made of soft elastic synthetic resin, with the front sheet member 21 forming the outer peripheral surface of the bag-shaped portion 23 and the back sheet member 22 forming the inner peripheral surface of the bag-shaped portion 23.

A circular first opening 24 is formed in the central and upper part of the membrane 17 in the longitudinal direction A. The insertion part 16 penetrates both ends of the membrane 17, and the insertion part 16 communicates with the upper part of the membrane 17 via the first opening 24.

As shown in Figures 8, 9 and 18, first and second circular through holes 26, 27 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.

As shown in Figures 4 to 6, the two sheet members 21, 22 are welded at the welded portion 29. This welded portion 29 has end welded portions 29a formed around the entire circumference of both ends of the membrane 17, a central welded portion 29b formed around the first opening 24, and a longitudinal welded portion 29c formed between the end welded portions 29a and the central welded portion 29b.

The front sheet member 21 has a number of slits 30 formed therein for releasing 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 area 31 where no slits 30 are formed is provided at the bottom of the front sheet member 21, and the slits 30 are formed in the area other than the non-formed area 31 and the welded portion 29.

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

As shown in Figures 4 and 7, the support member 18 is a resin circular tube with both ends open, and a circular second opening 33 is formed in the center and upper part of the support member 18 in the longitudinal direction A. As shown in Figures 8 and 9, when the support member 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 member 18 are aligned.

As shown in Figure 7, a bolt insertion hole 34 is formed in the center and bottom of the support member 18 in the longitudinal direction A. As shown in Figures 8 and 9, the position of the bolt insertion hole 34 in the support member 18 coincides with the center position of the second through hole 27 in the sheet member 22 on the back side of the membrane 17.

As shown in Figures 2, 6, and 8 to 14, the gas supply nozzle 19 is provided in the center of the membrane 17 in the longitudinal direction A, and has a circular tube portion 37, a flange portion 38, and a top plate portion 39. The tube portion 37 is inserted into the first through-hole 26 (see Figure 18) of the sheet member 21 on the front side of the membrane 17, and protrudes below the membrane 17. The lower end of the tube portion 37 is formed with a pair of cutout portions 41 and an inlet port 42 that opens into the air supply pipe 12.

The flange 38 is formed at the upper end of the tube 37 and projects outward in the radial direction of the tube 37, and as shown in Figures 8 and 9, it enters the bag-shaped portion 23 of the membrane 17. The outer peripheral surface of the flange 38 is formed with a plurality of outlet ports 43 that open into the bag-shaped portion 23. The entire periphery of the first through-hole 26 (see Figure 18) of the front sheet member 21 is welded to the underside of the flange 38, thereby attaching the gas supply nozzle 19 to the membrane 17.

The top plate portion 39 is formed at the upper end of the tube portion 37, and a bolt insertion hole 45 is formed in the top plate portion 39, penetrating in the vertical direction.

The gas supply nozzle 19 has an air flow passage 46 that is connected to the inlet 42 and the outlet 43. In addition, the upper surface of the gas supply nozzle 19 has a recess 47 that is curved in an arc shape along the outer circumferential surface of the support member 18.

As shown in Figures 8 and 9, the adapter 14 has an adapter body 50 that is provided between the membrane type air diffuser 10 and the air supply pipe 12, and a fastening member 51. As shown in Figures 15 to 17, the adapter body 50 is a rectangular parallelepiped member, and a recess 52 that is curved in an arc along the outer circumferential surface of the air supply pipe 12 is formed on the underside of the adapter body 50. In addition, a first circular insertion hole 53 that penetrates in the vertical direction is formed in the adapter body 50.

As shown in FIG. 1, the air supply pipe 12 is disposed below and perpendicular to 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 insertion holes 54 that penetrate the air supply pipe 12 from the inside to the outside.

The position of the first fitting hole 53 of the adapter body 50 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 tube portion 37 of the gas supply nozzle 19 is fitted from above into the first fitting hole 53 of the adapter body 50 and the second fitting hole 54 of the air supply pipe 12, and the lower end protrudes into the air supply pipe 12 through the second fitting hole 54.

As shown in Figures 8 and 9, the fastening member 51 is a member that connects the membrane type air diffuser 10 and the air supply pipe 12 with the adapter body 50 sandwiched between them, and has a T-head bolt 57 and a nut 58.

The head 57a of the T-head bolt 57 is fitted from below into both notches 41 of the tube portion 37 of the gas supply nozzle 19 and engages with the inner circumferential surface of the upper end of the air supply pipe 12. The bolt body 57b of the T-head bolt 57 is inserted from below into the bolt insertion hole 45 of the gas supply nozzle 19, the second through hole 27 of the sheet member 22 on the back side of the membrane 17, and the bolt insertion hole 34 of the support member 18, and protrudes into the support member 18. The nut 58 is screwed onto the T-head bolt 57 inside the support member 18.

The entire periphery of the second through hole 27 of the back sheet member 22 is sandwiched between the outer circumferential surface of the support member 18 and the top plate portion 39 of the gas supply nozzle 19. A cylindrical seal member 60 (packing) made of an elastic material such as rubber is fitted into the bolt insertion hole 34 of the support member 18. This prevents a portion of the air 11 supplied from 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 member 18 from between the bolt insertion hole 34 and the bolt main body portion 57b.

The operation of the above configuration is explained below.

As shown in Figures 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 path 46 and into the bag-shaped portion 23 of the membrane 17 through the outlet 43, causing the bag-shaped portion 23 to expand and release the air 11 in the bag-shaped portion 23 to the outside through the slits 30. As a result, a large number of air bubbles 4 are released from the membrane type air diffuser 10 into the water 3 to be treated.

Here, the membrane 17 formed in a tube shape has a bag-shaped portion 23, and since air 11 is supplied into the bag-shaped portion 23, there is no need to fix the end of the membrane 17 watertightly to the outer periphery of the support member 18 with a fixing device such as a band after inserting the tubular support member 18 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 air 11 can be prevented.

In addition, since the support member 18 is inserted into the insertion portion 16 of the membrane 17, the support member 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 member 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 member 18, and it mainly expands slightly toward the outside of the insertion portion 16 (i.e., the outside in the radial direction of the support member 18). This reduces the buoyancy acting on the membrane 17, and the support member 18 that fixes the membrane 17 so that it does not float up can be made smaller, and the membrane type air diffuser 10 can be made smaller accordingly.

In addition, since the gas supply nozzle 19 is provided at the center of the membrane 17 in the longitudinal direction A, 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 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 locally and unevenly from the membrane 17.

In addition, as shown in FIG. 1, the air supply pipe 12 is located below the membrane type air diffuser 10, so that a large number of air bubbles 4 are released into the water 3 being treated through the slits 30 of the membrane type air diffuser 10 without being blocked by the air supply pipe 12.

The manufacturing method of the membrane 17 of the membrane type aeration device 10 is described below.

First, as shown in FIG. 18, the tube portion 37 of the gas supply nozzle 19 is inserted into the first through-hole 26 of the front sheet member 21, which has multiple slits 30 formed therein, 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 sheet member 21.

Then, as shown in Figure 19, the outer edge 65 (see Figure 18) of the front sheet member 21 and the outer edge 66 (see Figure 18) of the back sheet member 22 are welded together to form a rectangular membrane sheet 67 having a bag-shaped portion 23. Note that the dotted area in Figure 19 is the welded portion 29 between the front sheet member 21 and the back sheet member 22.

Then, as shown in FIG. 19, the opposing long sides 68 of the membrane sheet 67 are joined together to form a tube, thereby forming the membrane 17, as shown in FIG. 4, which has 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.

This makes it possible to easily manufacture the tubular membrane 17 having the bag-shaped portion 23 .
Second Embodiment
In the first embodiment, as shown by the imaginary line in Figure 6, a non-forming area 31 in which no slits 30 are formed is formed in the lower part of the front sheet member 21, but in a second embodiment, the non-forming area 31 formed around the gas supply nozzle 19 may be extended upward from the lower part of the front sheet member 21.

In the above embodiments, as shown in Figs. 4 and 9, a circular tubular support member 18 and a cylindrical membrane 17 are shown, but the shapes are not limited to these. For example, an upper half semicircular tubular support member 18 and a semicylindrical membrane 17 may be used. Alternatively, a triangular tubular support member 18 and a cylindrical membrane 17 may be used, or a square (polygonal) tubular support member 18 and a cylindrical membrane 17 may be used.

In each of the above embodiments, air 11 is used as the gas for diffusion, but gases other than air 11 may also be used.

In each of the above embodiments, as shown in Figures 18 and 19, the front sheet member 21 and the back sheet member 22 are welded together to form a membrane sheet 67 having a bag-like portion 23. However, the front sheet member 21 may be divided into a plurality of sheet pieces, and one or more sheet pieces of the front sheet member 21 may be placed on the back sheet member 22 only in the area required to form the bag-like portion 23, and the periphery of the sheet piece may be welded to the back sheet member 22 to form a membrane sheet 67 having a bag-like portion 23.

In each of the above embodiments, as shown in FIG. 19, a rectangular membrane sheet 67 is used to form the tubular membrane 17, but a square membrane sheet 67 may also be used. In addition, the tubular membrane 17 may also be formed using a membrane sheet 67 that is a distorted quadrangle other than a rectangle or a square, or an approximate quadrangle.

1 Aeration equipment 3 Water to be treated (liquid)
4 Air bubbles 10 Membrane type air diffuser 11 Air (gas for air diffusion)
12 Air supply pipe 14 Adapter 16 Insertion part 17 Membrane 18 Support member 19 Gas supply nozzle (gas supply part)
21: front sheet member 22: rear sheet member 23: bag-shaped portion 30: slit 46: ventilation passage 67: membrane sheet 68: long side A of membrane sheet: longitudinal direction

Claims (4)

A membrane type air diffuser that releases air bubbles into a liquid,
A membrane formed in a tubular shape having an insertion portion at its center;
A tubular support member inserted into the membrane insertion portion;
A gas supply unit,
The membrane has, at least in a portion thereof, a bag-shaped portion formed in a bag shape by two sheet members on the front and back sides,
the gas supply unit has an air passage communicating from the outside to the inside of the bag-shaped portion of the membrane;
A membrane type air diffuser characterized in that a sheet member constituting the outer peripheral surface of the bag-shaped portion of the membrane is formed with a plurality of slits for releasing to the outside the gas supplied into the bag-shaped portion through the ventilation flow path of the gas supply section. An aeration system having the membrane type aeration device according to claim 1,
An air supply pipe for supplying gas to the membrane type air diffuser is provided.
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,
The gas supply is fitted into the adapter,
An aeration system characterized in that the aeration flow path is connected to the inside of the air supply pipe and the inside of the bag-shaped portion of the membrane. The adapter is installed at the bottom of the membrane type aeration device.
3. The air diffusion system according to claim 2, wherein the air supply pipe is disposed below the membrane type air diffusion device . A method for manufacturing the membrane of the membrane type air diffuser according to claim 1,
A membrane sheet having a bag-shaped portion and a rectangular outer shape is formed by two sheet members on the front and back sides,
A method for producing a membrane, comprising joining two opposing sides of a membrane sheet to form a tubular shape.

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