CN214404880U - Back flush air valve - Google Patents

Abstract

The utility model relates to the field of valves, especially, relate to back flush air valve. A back-washing air valve comprises a valve body and a back-washing auxiliary pipeline, wherein the valve body is provided with a water inlet and a first connecting port which are communicated with each other, a first cut-off part is connected to the water inlet, and the back-washing auxiliary pipeline is connected to the first connecting port; the back flush air valve further comprises a filter screen and a first cut-off part, one end of the first connecting port is far away from the back flush auxiliary pipeline, the first cut-off part is connected to the water inlet, the filter screen is arranged in the water inlet, a drain outlet is further formed in the valve body, the drain outlet is opposite to the filter screen, the first connecting port is far away from the filter screen, and the back flush auxiliary pipeline reaches the drain outlet and can form a flow channel to wash the filter screen. The utility model has the advantages that: the backwash filter screen has strong circulation capacity and strong sewage discharge capacity.

Description

Back flush air valve

Technical Field

The utility model relates to the field of valves, especially, relate to back flush air valve.

Background

The air valve is used in the equipment on water delivery and distribution, municipal water supply pipe network, can exhaust in a large number when the pipe network fills water, can breathe in a large number when the negative pressure appears in the pipe network, plays the micro-exhaust effect when the pipe network normally works.

The conventional air valve is easy to accumulate sundries in the valve body to block the valve body, so that the normal work of the air valve is influenced.

SUMMERY OF THE UTILITY MODEL

Based on this, the utility model provides a back flush air valve to above-mentioned technical problem, technical scheme as follows:

a back-washing air valve comprises a valve body and a back-washing auxiliary pipeline, wherein the valve body is provided with a water inlet and a first connecting port which are communicated with each other, and the back-washing auxiliary pipeline is connected with the first connecting port; the back flush air valve further comprises a filter screen and a first cut-off part, one end of the first connecting port is far away from the back flush auxiliary pipeline, the first cut-off part is connected to the water inlet, the filter screen is arranged in the water inlet, a drain outlet is further formed in the valve body, the drain outlet is opposite to the filter screen, the first connecting port is far away from the filter screen, and the back flush auxiliary pipeline reaches the drain outlet and can form a flow channel to wash the filter screen.

So set up, can carry out the backwash to the filter screen, avoid the filter screen to be blockked up and influence the normal work of back flush air valve by debris, simultaneously, on the valve body was located to the drain, separately set up with following first shut-off piece, can increase the bore of drain, can increase the blowdown ability, locate the filter screen in the water inlet, can increase the area of filter screen to increase the circulation ability of filter screen, improve the blowdown ability.

In one embodiment, the filter screen is in a U shape, a V shape or a C shape.

So set up, can increase the filter area of filter screen, and increase the circulation ability of filter screen.

In one embodiment, the backwash air valve further comprises a float and a positioning part, the valve body is internally provided with a valve cavity, the float is arranged in the valve cavity and can move along the axial direction of the valve body, and the positioning part is arranged in the valve cavity and outside the float and can guide the movement of the float.

So set up, when the float moves along with the rising or the decline of liquid level, location portion can play the guide orientation effect, leads to the motion of float, when preventing that the medium from entering in the twinkling of an eye, leads to the float to incline because of the buoyancy that receives is inhomogeneous to make the medium take place to leak, simultaneously, the blockking of location portion can make the float move steadily, can prevent that the medium from assaulting the float, improves the shock resistance of float.

In one embodiment, the positioning portion is a positioning net provided around an outer peripheral side of the float.

So set up, further guide the motion of float, and make the compact structure of back flush air valve.

In one embodiment, the backwash air valve comprises a valve cover, the valve cover is arranged at one end of the valve body in a covering mode, a clamping groove is formed in one end, close to the valve body, of the valve cover and faces one side of the valve cavity, a connecting piece is arranged on the positioning portion, and the connecting piece is clamped in the clamping groove and abuts against the end face of the valve body.

So set up to can dismantle the connection to location portion, make things convenient for the installation and the dismantlement of location portion.

In one embodiment, the valve cavity is internally provided with an installation part, the installation part is connected to the inner wall of the valve body, one side of the installation part, facing the positioning part, is provided with a groove, and one end of the positioning part extends into the groove.

So set up, can strengthen the stability of location portion.

In one embodiment, the valve cover is provided with an exhaust port, a valve seat is arranged at the exhaust port, the valve seat is provided with a sealing groove, a sealing element is arranged in the sealing groove, one part of the sealing element is arranged in the sealing groove, and the other part of the sealing element extends out of the sealing groove and can be abutted against the outer wall of the float.

In one embodiment, the backwash air valve further comprises a support part, the support part is connected to the inner wall of the valve body through the mounting part, the side surface of the support part close to one side of the floater is matched with the outer wall of the floater, the support part can support the floater, and the support part is partially arranged in the filter screen in a penetrating mode.

So set up, can play direction, supporting role to the float, and the supporting part can play the supporting role to the filter screen.

In one embodiment, the backwashing auxiliary pipeline comprises a pipeline, the backwashing air valve further comprises a second exhaust valve connected with the backwashing auxiliary pipeline, the first cut-off part is provided with a second connecting port and a first opening which are communicated with each other, two ends of the pipeline are connected with the second connecting port and the first connecting port, and the first cut-off part can control the communication or the separation between the first opening and the water inlet; and a second cutting part is arranged at the sewage draining port.

In one embodiment, the backwash auxiliary pipeline further comprises a third cut-off piece and a fourth cut-off piece which are arranged on the pipeline, the pipeline comprises a hose and a hard pipe, the third cut-off piece is connected to the water inlet through the hard pipe, one end of the third cut-off piece is connected to the fourth cut-off piece through the hose, the other end of the third cut-off piece is connected to the second connecting port through the hard pipe, and the fourth cut-off piece is communicated with the first connecting port.

By the arrangement, the weight of the backwashing auxiliary pipeline can be reduced, and the hard pipe plays a supporting role in the backwashing auxiliary pipeline.

Compared with the prior art, the utility model provides a back flush air valve is through setting up back flush auxiliary line to seted up the drain on the valve body, carry out the backflushing with the filter screen, the medium after will washing passes through the drain and flows, locates the drain on the valve body, can increase the bore of drain, thereby increases the dirt discharge ability, and the setting can increase filter area at the intraoral filter screen of intaking, thereby increases the flow capacity of filter screen, and then strengthens the dirt discharge ability.

Drawings

Fig. 1 is a schematic structural view of a back-flushing air valve provided by the present invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 at A;

fig. 3 is a partial enlarged view of fig. 2 at B;

fig. 4 is a schematic diagram of the process of the backwashing air valve during backwashing.

The symbols in the drawings represent the following meanings:

100. a backwash air valve; 10. a valve body; 11. a valve cavity; 111. an installation part; 1111. a groove; 13. a water inlet; 14. a first connection port; 15. a sewage draining outlet; 16. a second cut-off; 20. a valve cover; 201. an exhaust port; 21. a card slot; 22. a valve seat; 221. a sealing groove; 222. a seal member; 2221. a first inclined plane; 2222. a second inclined plane; 30. an exhaust cover; 40. a float; 41. a guide bar; 50. a filter screen; 60. a support portion; 61. a support bracket; 62. a guide member; 621. an inner cavity; 622. a water inlet hole; 70. a positioning part; 71. positioning a net; 72. a connecting member; 80. back flushing the auxiliary pipeline; 81. a pipeline; 82. a first cutoff member; 821. a second connection port; 822. a first opening; 823. a second opening; 84. a second exhaust valve; 85. a third cut-off; 86. a three-way pipe; 87. a filter; 88. a hose; 89. a fourth cut-off; 801. and (4) hard tubes.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

It will be understood that when an element is referred to as being "mounted on" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. When an element is referred to as being "secured to" another element, it can be directly secured to the other element or intervening elements may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1 to 4, the present invention provides a back-flushing air valve 100 (hereinafter referred to as an air valve), which is applied to a pipeline system (not shown), such as a central heating system or a central air conditioning system, and is installed at the highest position of the pipeline system for exhausting gas in the pipeline system to prevent the pipeline system from generating air lock; the air valve 100 prevents the piping system from generating negative pressure to cause the piping to vibrate or break when the piping system needs to be stopped due to a malfunction. In other embodiments, the air valve 100 may also be applied to a boiler heating system or the like.

Specifically, referring to fig. 1, the air valve 100 includes a valve body 10, a valve cover 20, an exhaust cover 30 and a float 40, the valve body 10 has a valve cavity 11 therein, the valve cover 20 is covered at one end of the valve body 10, the valve cover 20 is opened with an exhaust port 201 communicating with the valve cavity 11, the exhaust cover 30 is covered at the exhaust port 201, the exhaust port 201 communicates with the atmosphere, and the float 40 is disposed in the valve cavity 11. When the air valve 100 is in the exhaust state, the float 40 descends due to gravity, the exhaust port 201 is opened, and air is exhausted from the exhaust port 201 through the gap; as the liquid level rises due to the air discharge, the float 40 floats upward due to the buoyancy of the medium, and the sealing end surface of the float 40 gradually presses the exhaust port 201 until the entire exhaust port 201 is completely blocked, at which time the air valve 100 is completely closed. In this embodiment, the float 40 is a floating ball, and in other embodiments, the float 40 may also be a float.

A water inlet 13 and a first connecting port 14 are formed in one end, away from the valve cover 20, of the valve body 10, the water inlet 13 and the first connecting port 14 are both communicated with the valve cavity 11, the water inlet 13 is used for allowing a medium to flow in, and the first connecting port 14 is used for connecting a backwashing auxiliary pipeline 80; the side of the valve body 10 close to the end of the water inlet 13 is provided with a sewage draining outlet 15 for draining sewage, the sewage draining outlet 15 is arranged on the valve body 10 and can increase the caliber of the sewage draining outlet 15, so that the sewage draining capability is increased, and the sewage draining outlet 15 is provided with a second cut-off piece 16 for controlling the opening or closing of the sewage draining outlet 15. The second shut-off member 16 may be a shut-off member such as a ball valve or a stop valve. It can be understood that the drain outlet of the existing backwashing air valve is arranged on the first cut-off part, and the caliber of the drain outlet cannot be larger due to the limited space on the first cut-off part, so that the sewage discharge capability can be influenced.

The valve chamber 11 is provided with a mounting portion 111, and the mounting portion 111 is connected to the inner wall of the valve body 10.

The valve cover 20 is provided with a locking groove 21 at one end close to the valve body 10 and facing the inside of the valve cavity 11.

Referring to fig. 3, a valve seat 22 is disposed in the valve cover 20, a sealing groove 221 is disposed on the valve seat 22, and a sealing element 222 is disposed in the sealing groove 221, such that when the float 40 blocks the exhaust port 201, the sealing element 222 is attached to an outer sidewall of the float 40 to block the exhaust port 201. The valve seat 22 is capable of supporting the float 40 and functions to protect the seal 222.

The section of the sealing groove 221 is of a mirror image '7' shape, and then the sealing element 222 is also of a mirror image '7' shape, wherein part of the sealing element 222 is arranged in the sealing groove 221, the other part of the sealing element extends out of the sealing groove 221, and the extending part can be attached to the outer wall of the float 40.

The seal 222 is made of rubber to form a soft seal against the float 40, and the seal 222 can wrap around the float 40 to better seal in combination with the hard seal of the valve seat 22.

Further, the portion of the sealing member 222 extending out of the sealing groove 221 is chamfered near the side surface of the exhaust port 201 to form a first inclined surface 2221, the first inclined surface 2221 is surrounded to form a circular truncated cone shape, and the first inclined surface 2221 can be attached to the outer wall of the float 40, so that the sealing member 222 can be better attached to the float 40.

Preferably, the portion of the sealing member 222 extending out of the sealing groove 221 is chamfered away from the side surface of the exhaust port 201 to form a second inclined surface 2222, one end of the first inclined surface 2221 and one end of the second inclined surface 2222 are engaged with each other so that one end of the sealing member 222 forms a sharp angle, and when the medium floats up and acts on the sealing member 222, the second inclined surface 2222 is arranged to increase the force of the sealing member 222 perpendicular to the float 40 so that the first inclined surface 2221 is better attached to the float 40. It will be appreciated that without the second inclined surface 2222, the media acts on the end surface of the bottom of the seal 222 creating an upward force that reduces the force of the seal 222 perpendicular to the float 40.

The air valve 100 further comprises a filter 50, the filter 50 being arranged in the inlet 13, the filter 50 being arranged to filter media entering the valve chamber 11 to protect the air valve 100 from being clogged by impurities, the filter 50 being arranged close to the first connection opening 14 in relation to the drain opening 15. It can be understood that the filter screen 50 disposed in the water inlet 13 is convenient to be made into various shapes, and the filtering area can be enlarged, so that the circulation capacity of the filter screen 50 is enhanced, and the sewage discharge capacity is enhanced.

The filter screen 50 is "V" type, "U" type or "C" type, can understand, and the filter screen 50 that so sets up can increase filter area, improves filtration efficiency, strengthens filter screen 50's flow capacity simultaneously, wherein when filter screen 50 is "C", its opening is kept away from valve pocket 11. In this embodiment, the filter screen 50 is in a "U" shape, and the opening of the filter screen 50 is far away from the valve cavity 11 to adapt to the flow direction of the medium, and in other embodiments, the filter screen 50 may also be in other shapes that can increase the filter area.

The air valve 100 further includes a support portion 60, the support portion 60 being connected to the mounting portion 111, the support portion 60 supporting the float 40.

The support part 60 comprises a support bracket 61 and a guide part 62, the support bracket 61 and the guide part 62 are connected with each other, the support bracket 61 is arranged at the bottom of the floater 40, the outer side wall of the support bracket 61 facing the floater 40 is matched with the outer wall of the floater 40, the guide rod 41 is arranged in the filter screen 50 in a penetrating way, the guide rod 41 plays a supporting role for the filter screen 50, and when the floater 40 sinks, the support bracket 61 plays a supporting role for the floater 40. It should be noted that, since the float 40 of the present embodiment is a floating ball, the outer side wall of the support bracket 61 is arc-shaped.

The guide member 62 defines an inner cavity 621, one end of the float 40 is provided with a guide rod 41, and the guide rod 41 is disposed in the inner cavity 621 and can reciprocate in the inner cavity 621 to guide the movement of the float 40.

The guide member 62 is provided with a water inlet hole 622 respectively communicating with the inner cavity 621 and the valve cavity 11, and water in the water inlet 13 can enter from the water inlet hole 622.

The water inlet holes 622 are provided in plural numbers, and the plural water inlet holes 622 are uniformly distributed along the circumferential direction of the guide member 62 to increase the water inlet amount and make the medium uniformly enter the inner cavity 621.

Referring to fig. 2, the air valve 100 further includes a positioning portion 70, the positioning portion 70 is disposed in the valve cavity 11 and outside the float 40, and is capable of guiding the movement of the float 40, when the float 40 moves in the valve cavity 11 along the axial direction, the positioning portion 70 plays a guiding and positioning role for the float 40 to prevent the float 40 from tilting under the impact of the medium of the float 40, so that the float 40 cannot seal the air outlet 201, and the medium leaks.

The positioning portion 70 is a positioning net 71, and the positioning net 71 is disposed around the outer circumferential side of the float 40 to reinforce the guiding function to the float 40 and make the back flush air valve 100 compact.

The positioning portion 70 is provided with a connecting member 72, the side surface of the mounting portion 111 facing the valve cover 20 is provided with a groove 1111, the connecting member 72 is clamped in the clamping groove 21, and one end of the positioning portion 70 far away from the valve cover 20 is arranged in the groove 1111 to fix the positioning portion 70. It will be appreciated that the positioning portion 70 can also act as a cushion for the float 40, preventing media from impacting the float 40, and increasing the impact resistance of the float 40.

The air valve 100 further includes a backwash auxiliary line 80 and a first cutoff member 82, the backwash auxiliary line 80 having one end connected to the first cutoff member 82 and the other end connected to the first connection port 14, the backwash auxiliary line 80 being capable of backwashing the filter screen 50.

The first cut-off member 82 has a first opening 822 and a second opening 823, the second opening 823 of the first cut-off member 82 is connected to the water inlet 13, the first opening 822 is used for inflow of a medium, and the first cut-off member 82 is used for controlling communication or disconnection between the first opening 822 and the water inlet 13.

Referring to fig. 4, the back-flushing auxiliary pipeline 80 includes a pipeline 81, the first cut-off member 82 is provided with a second connection port 821, the second connection port 821 is communicated with the first opening 822, and two ends of the pipeline 81 are respectively connected to the second connection port 821 and the first connection port 14. When the maintenance is needed, the first cut-off member 82 is closed, the medium enters the pipe 81 from the first opening 822, enters the water inlet 13 from the first connecting port 14, the filter screen 50 is backwashed, and the washed medium flows out from the sewage outlet 15. In this embodiment, the first shut-off member 82 is a gate valve, and in other embodiments, the first shut-off member 82 may also be a butterfly valve, ball valve, or other shut-off member.

The backwash air valve 100 further includes a second discharge valve 84, and the second discharge valve 84 is connected to the backwash assisting line 80 such that the second discharge valve 84 communicates with the first connection port 14. In the present embodiment, the second exhaust valve 84 is a micro exhaust valve for exhausting micro air in the medium, and of course, in other embodiments, the second exhaust valve 84 may be other types of exhaust valves.

The backwashing auxiliary pipeline 80 further comprises a third cut-off piece 85 and a three-way pipe 86, the three-way pipe 86 and the third cut-off piece 85 are arranged on the pipeline 81, one end of the three-way pipe 86 is connected to an inlet of the second exhaust valve 84, and the other two ends are respectively connected to the third cut-off piece 85 and the first connecting port 14 through the pipeline 81, namely, the second exhaust valve 84 is respectively connected with the third cut-off piece 85 and the first connecting port 14 through the three-way pipe 86, and the third cut-off piece 85 is used for controlling the opening and closing of the backwashing auxiliary pipeline 80. In the present embodiment, the third block 85 is a ball valve, and in other embodiments, the third block 85 may also be another block such as a stop valve.

The backwashing auxiliary pipeline 80 further comprises a fourth cut-off member 89, the pipeline 81 comprises a hose 88 and a hard pipe 801, the fourth cut-off member 89 is connected with the third cut-off member 85 through the hose 88, the third cut-off member 85 is connected with the second connecting port 821 through the hard pipe 801, one end, far away from the hose 88, of the fourth cut-off member 89 is connected with the three-way pipe 86, and the hard pipe 801 plays a supporting role in supporting the backwashing auxiliary pipeline 80. The hose 88 can reduce the weight of the air valve 100, and the hose 88 can be bent appropriately to provide flexibility. In this embodiment, the hose 88 is a stainless steel braided hose 88, the stainless steel braided hose 88 has good flexibility and wear resistance, and in other embodiments, the hose 88 may be another hose 88 such as rubber. The fourth cut-off member 89 is provided to facilitate the cutting-off of the fourth cut-off member 89 and the third cut-off member 85, and the hose 88 is replaced and repaired.

Further, the back flush air valve 100 further includes a filter 87, the filter 87 is disposed at an inlet of the second discharge valve 84 to protect the second discharge valve 84 from impurities, and the filter 87 is disposed between the second discharge valve 84 and the tee 86.

When the air valve 100 is in a normal working state, the first cut-off member 82 is opened, the second cut-off member 16 and the third cut-off member 85 are closed, the medium enters the water inlet 13 from the first cut-off member 82, enters the water inlet 622 from the water inlet hole 622, floats the float 40, performs air exhaust, and when the liquid level of the medium continues to rise, the float 40 abuts against the valve seat 22, the float 40 seals the air outlet 201, and the air exhaust is finished; when the air valve 100 needs to be overhauled, the first cut-off part 82 is closed, the second cut-off part 16, the third cut-off part 85 and the fourth cut-off part 89 are opened, a medium enters the pipeline 81 from the first opening 822 through the second connecting port 821 and then enters the water inlet 13 from the first connecting port 14, the filter screen 50 is reversely flushed, and the flushed sewage is discharged from the sewage discharge port 15.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims (10)

1. A back flush air valve comprises a valve body (10) and a back flush auxiliary pipeline (80), wherein the valve body (10) is provided with a water inlet (13) and a first connecting port (14) which are communicated with each other, and the back flush auxiliary pipeline (80) is connected to the first connecting port (14);

the back flush air valve is characterized by further comprising a filter screen (50) and a first cut-off part (82), wherein the back flush auxiliary pipeline (80) is far away from one end of the first connecting port (14) and is connected with the first cut-off part (82), the first cut-off part (82) is connected with the water inlet (13), the filter screen (50) is arranged in the water inlet (13), a sewage draining outlet (15) is further formed in the valve body (10), the sewage draining outlet (15) is opposite to the first connecting port (14) in the filter screen (50), and the back flush auxiliary pipeline (80) reaches the sewage draining outlet (15) can form a flow channel so as to wash the filter screen (50).

2. The backwash air valve according to claim 1, wherein the filter screen (50) is "U" -shaped, "V" -shaped or "C" -shaped.

3. The backwash air valve according to claim 1, further comprising a float (40) and a positioning portion (70), wherein the valve body (10) has a valve chamber (11) therein, the float (40) is disposed in the valve chamber (11) and can move along the axial direction of the valve body (10), and the positioning portion (70) is disposed in the valve chamber (11) and outside the float (40) and can guide the movement of the float (40).

4. The backwash air valve according to claim 3, wherein the positioning portion (70) is a positioning net (71), and the positioning net (71) is provided around an outer peripheral side of the float (40).

5. The backwash air valve according to claim 3, further comprising a valve cover (20), wherein the valve cover (20) is disposed at one end of the valve body (10), a clamping groove (21) is formed in one side, which faces the valve cavity (11), of the valve cover (20) close to one end of the valve body (10), a connecting member (72) is disposed on the positioning portion (70), and the connecting member (72) is clamped in the clamping groove (21) and abuts against an end surface of the valve body (10).

6. The backwash air valve according to claim 3, wherein a mounting part (111) is arranged in the valve chamber (11), the mounting part (111) is connected to the inner wall of the valve body (10), a groove (1111) is formed in one side of the mounting part (111) facing the positioning part (70), and one end of the positioning part (70) extends into the groove (1111).

7. The backwash air valve according to claim 5, wherein an exhaust port (201) is formed in the valve cover (20), a valve seat (22) is arranged at the exhaust port (201), a sealing groove (221) is formed in the valve seat (22), a sealing member (222) is arranged in the sealing groove (221), a part of the sealing member (222) is arranged in the sealing groove (221), and the other part of the sealing member extends out of the sealing groove (221) and can be abutted against the outer wall of the float (40).

8. The backwash air valve according to claim 6, further comprising a support portion (60), wherein the support portion (60) is connected to an inner wall of the valve body (10) through the mounting portion (111), a side surface of the support portion (60) near the float (40) is adapted to an outer wall of the float (40) to support the float (40), and the support portion (60) is partially inserted into the filter screen (50).

9. The backwash air valve according to claim 1, wherein the backwash auxiliary line (80) comprises a pipe (81), the backwash air valve further comprises a second exhaust valve (84) connected to the backwash auxiliary line (80), the first cut-off member (82) is provided with a second connection port (821) and a first opening (822) which are communicated with each other, two ends of the pipe (81) are connected to the second connection port (821) and the first connection port (14), and the first cut-off member (82) can control the communication or the separation between the first opening (822) and the water inlet (13); and a second cut-off piece (16) is arranged at the sewage outlet (15).

10. The backwash air valve according to claim 9, wherein the backwash auxiliary line (80) further comprises a third shut-off member (85) and a fourth shut-off member (89) provided on the pipe (81), the pipe (81) comprises a hose (88) and a hard pipe (801), one end of the third shut-off member (85) is connected to the fourth shut-off member (89) through the hose (88), the other end of the third shut-off member is connected to the second connection port (821) through the hard pipe (801), and the fourth shut-off member (89) is communicated with the first connection port (14).

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