Breather valve

Abstract

The utility model relates to the technical field of valves, and discloses a breather valve which comprises a valve body and a valve clack assembly, and the valve body is provided with a conveying cavity and a suction cavity. The valve clack assembly is movably arranged in the valve body and comprises a valve clack body and a first sealing piece. The valve clack assembly has a closed state in which the valve clack assembly abuts against the inner wall of the valve body in a sealed mode and an open state separated from the inner wall of the valve body. When the pressure of the conveying cavity is lower than the designed pressure of the pipeline, the valve clack assembly is in an open state, the conveying cavity communicates with the suction cavity, and the conveying cavity sucks a medium; when the pressure of the conveying cavity is larger than or equal to the designed pressure of the pipeline, the valve clack assembly is in a closed state, the conveying cavity and the suction cavity are blocked, and non-return of a medium is achieved. According to the breather valve, the suction cavity and the conveying cavity of the valve body can be sealed and blocked, and inner leakage is avoided. In this way, the good sealing effect between the valve clack assembly and the valve body can be guaranteed, the stable pressure in a pipeline is guaranteed, and therefore the mechanical operation performance is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of valves, in particular to a breathing valve. Background Art

[0002] Valves are indispensable in the fields of nuclear power and petrochemicals.

[0003] The breathing valve has a special purpose. For example, the breathing valve used in the nuclear power industry is mainly used in the auxiliary pipeline of the emergency diesel generator. When there is diesel in the pipeline, it has a certain pressure. After the diesel is used, the pressure decreases, the breathing valve opens, and the diesel is sucked into the pipeline; when the diesel pressure in the pipeline reaches the required pressure, the breathing valve automatically closes.

[0004] During the closing process of the breathing valve, a good sealing effect is required between the valve disc and the valve body. Otherwise, the inhaled medium is easy to flow back, and the check effect is poor, which can easily affect the working pressure of the breathing valve, making the pressure in the pipeline unstable and causing pipeline pressure fluctuations, thereby affecting the working performance of the machinery. Utility Model Content

[0005] In view of this, the utility model provides a breathing valve to solve the problem of pipeline pressure fluctuation due to poor sealing effect between the valve disc and the valve body.

[0006] In the first aspect, the utility model provides a breathing valve, including a valve body and a valve flap assembly, the valve body having a delivery chamber suitable for connecting with a pipeline and a suction chamber suitable for connecting with a medium source; the valve flap assembly is movably arranged in the valve body, the valve flap assembly includes a valve flap body and a first sealing member arranged on the valve flap body, the first sealing member is suitable for abutting and sealing with the inner wall of the valve body; the valve flap assembly has a closed state in which it abuts and seals with the inner wall of the valve body and an open state separated from the inner wall of the valve body; when the pressure in the delivery chamber is lower than the design pressure of the pipeline, the valve flap assembly is in an open state, the delivery chamber and the suction chamber are connected, and the delivery chamber inhales the medium; when the pressure in the delivery chamber is greater than or equal to the design pressure of the pipeline, the valve flap assembly is in a closed state, the delivery chamber and the suction chamber are blocked, thereby realizing a check on the medium.

[0007] In an optional embodiment, the inner wall of the valve body has a sealing seat, which divides the valve body into a delivery chamber and a suction chamber; the sealing seat has a mounting hole and a flow channel hole; the valve flap assembly is arranged in the mounting hole, and the valve flap assembly also includes a valve stem, the valve flap body is located in the delivery chamber, one end of the valve stem is connected to the valve flap body, and the other end of the valve stem passes through the mounting hole and extends into the suction chamber; in the open state, the delivery chamber and the suction chamber are connected through the flow channel hole.

[0008] In an optional embodiment, the valve flap assembly also includes an elastic return member, which is arranged in the suction chamber and connected between the valve stem and the sealing seat; the elastic return member is suitable for applying an elastic force from the delivery chamber to the suction chamber to the valve stem.

[0009] In an optional embodiment, the valve flap assembly also includes a cover plate, which is connected to the valve flap body, and the first seal includes a soft sealing material. The first seal is arranged between the cover plate and the valve flap body, and the first seal includes an exposed portion protruding from the cover plate and the valve flap body. In a closed state, the exposed portion of the first seal is pressed against the inner wall of the valve body.

[0010] In an optional embodiment, the cover plate includes a cover plate body and a clamping edge arranged on the outer wall of the cover plate body, the first seal includes a seal body and a sealing edge arranged on the outer wall of the seal body, the seal body is fixed between the end faces of the cover plate body and the valve flap body, and the sealing edge is fixed between the clamping edge of the cover plate and the outer wall of the valve flap body.

[0011] In an optional embodiment, a sealing surface of the sealing seat facing the conveying chamber is provided with a hard sealing layer, and in a closed state, the first sealing member abuts against the hard sealing layer for sealing.

[0012] In an optional embodiment, a threaded section is provided at the upstream end of the valve stem, and the threaded section is connected to an adjusting nut. A limiting sleeve is sleeved on the valve stem, and the limiting sleeve includes a cylinder body and a limiting ridge. The elastic reset member abuts between the sealing seat and the limiting ridge, and the upstream end of the limiting sleeve abuts against the adjusting nut.

[0013] In an optional embodiment, a valve cover is further included, wherein the upstream end of the valve cover is connected to the valve body, and the valve cover and the valve body are sealed by a second sealing member.

[0014] In an optional embodiment, the downstream end of the valve cover has an adaptable connection structure suitable for connection with a pipeline, and the adaptable connection structure includes a threaded connection structure, a flange connection structure or a plug-in connection structure.

[0015] In an optional embodiment, a filter assembly is also included, which includes a mounting base and a filter basket, and the mounting base is connected to the upstream end of the valve body; the filter basket is connected to the mounting base through a connecting piece, the inner cavity of the filter basket is connected to the suction cavity, and one end of the valve stem extends into the filter basket.

[0016] Beneficial effect: The breathing valve provided by the utility model has a sealing connection between the valve flap assembly and the sealing seat of the valve body through the first sealing member, so that the suction chamber and the delivery chamber of the valve body are sealed and blocked to avoid internal leakage. In this way, a good sealing effect can be ensured between the valve flap assembly and the valve body, and the pressure in the pipeline is stable, thereby ensuring the performance of the mechanical operation. At the same time, the breathing valve provides the function of inhaling medium and non-return function. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A cross-sectional view of a breathing valve according to an embodiment of the utility model;

[0019] Figure 2 for Figure 1 Schematic diagram of the structure of the middle valve disc assembly;

[0020] Figure 3 for Figure 1 Schematic diagram of the structure of the middle valve body;

[0021] Figure 4 for Figure 3 A top view of the valve body is shown;

[0022] Figure 5 for Figure 1 A schematic diagram of the structure of the middle filter assembly;

[0023] Figure 6 for Figure 1 Schematic diagram of the structure of the middle valve cover;

[0024] Figure 7 for Figure 6 A top view of the valve cover is shown.

[0025] Description of reference numerals:

[0026] 1. Valve body; 11. Sealing seat; 12. Delivery chamber; 13. Suction chamber; 14. Mounting hole; 15. Flow channel hole; 16. Hard sealing layer; 2. Valve disc assembly; 21. Valve disc body; 22. Valve stem; 23. Elastic reset member; 24. First sealing member; 240. Exposed portion; 25. Cover plate; 26. Locking plate; 27. First fastener; 28. Adjusting nut; 29. ​​Limiting sleeve; 3. Valve cover; 31. Adapter connection structure; 32. Torque transmission surface; 4. Second sealing member; 5. Filter assembly; 51. Mounting base; 52. Filter basket; 53. Connector; 54. Second fastener. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0028] It should be noted that, along the conveying direction of the medium, the end located upstream is the “upstream end”, and correspondingly, the end located downstream is the “downstream end”.

[0029] Combine the following Figures 1 to 7 , describing an embodiment of the utility model.

[0030] According to an embodiment of the utility model, on the one hand, a breathing valve is provided, comprising a valve body 1 and a valve flap assembly 2. The valve body 1 has a delivery chamber 12 suitable for communicating with a pipeline and a suction chamber 13 suitable for communicating with a medium source; the valve flap assembly 2 is movably arranged in the valve body 1, and the valve flap assembly 2 includes a valve flap body 21 and a first sealing member 24 arranged on the valve flap body 21, and the first sealing member 24 is suitable for abutting and sealing with the inner wall of the valve body 1; the valve flap assembly 2 has a closed state in which it abuts and seals with the inner wall of the valve body 1 and an open state in which it is separated from the inner wall of the valve body 1; when the pressure of the delivery chamber 12 is lower than the design pressure of the pipeline, the valve flap assembly 2 is in an open state, the delivery chamber 12 and the suction chamber 13 are connected, and the delivery chamber 12 inhales the medium; when the pressure of the delivery chamber 12 is greater than or equal to the design pressure of the pipeline, the valve flap assembly 2 is in a closed state, the delivery chamber 12 and the suction chamber 13 are blocked, and the medium is prevented from flowing back.

[0031] In the breathing valve provided by the embodiment of the utility model, the valve flap assembly 2 and the sealing seat 11 of the valve body 1 are sealed and connected by the first sealing member 24, so that the suction chamber 13 and the delivery chamber 12 of the valve body 1 are sealed and blocked to avoid internal leakage. In this way, a good sealing effect can be ensured between the valve flap assembly 2 and the valve body 1, and the pressure in the pipeline is stable, thereby ensuring the performance of the mechanical operation.

[0032] In some embodiments, the inner wall of the valve body 1 has a sealing seat 11, which divides the valve body 1 into a delivery chamber 12 and a suction chamber 13; the sealing seat 11 has a mounting hole 14 and a flow channel hole 15; the valve flap assembly 2 is arranged in the mounting hole 14, and the valve flap assembly 2 also includes a valve stem 22, the valve flap body 21 is located in the delivery chamber 12, one end of the valve stem 22 is connected to the valve flap body 21, and the other end of the valve stem 22 passes through the mounting hole 14 and extends into the suction chamber 13; in the open state, the delivery chamber 12 and the suction chamber 13 are connected through the flow channel hole 15.

[0033] By providing the valve stem 22 , the valve stem 22 is inserted into the mounting hole 14 of the sealing seat 11 , thereby guiding the movement of the valve flap assembly 2 .

[0034] In some embodiments, a plurality of flow channel holes 15 are provided, and the plurality of flow channel holes 15 are arranged at intervals around the mounting hole 14, so that the flow capacity of the end is not affected. Further, according to actual needs and the size of the flow channel holes 15, eight to ten flow channel holes 15 are provided.

[0035] In some embodiments, the valve flap assembly 2 also includes an elastic return member 23, which is arranged in the suction chamber 13 and connected between the valve stem 22 and the sealing seat 11; the elastic return member 23 is suitable for applying an elastic force from the delivery chamber 12 to the suction chamber 13 to the valve stem 22.

[0036] In this embodiment, the elastic force from the delivery chamber 12 to the suction chamber 13 is applied to the valve stem 22 by the elastic return member 23 , so as to provide the valve flap with a restoring force toward the suction chamber 13 .

[0037] The valve flap assembly 2 switches from a closed state to an open state, which is a "suction" action. At this time, the medium can be sucked from the suction chamber 13 to the delivery chamber 12; the valve flap assembly 2 switches from an open state to a closed state, which is a "exhalation" action. The delivery chamber 12 and the suction chamber 13 can be blocked, and no more medium is sucked.

[0038] Specifically, take the breathing valve used in the auxiliary pipeline of the emergency diesel generator as an example. Take the suction chamber 13 of the breathing valve connected to the diesel tank as an example. The working principle of the breathing valve is: there is no additional pressure in the diesel tank. The breathing valve is installed at the end of the pipeline and goes deep into the diesel tank. According to the use of the medium diesel in the pipeline, after the original medium diesel is used up, a suction state appears. At this time, the valve flap assembly 2 of the breathing valve moves and is in an open state. Oil is taken from the diesel tank. The diesel enters the delivery chamber 12 through the suction chamber 13 and is sent to the pipeline. When the pipeline is replenished with diesel, the pressure increases and no more suction is required. At this time, the breathing valve appears in an exhalation state, and the valve flap assembly 2 moves and is in a closed state to achieve a check to ensure that the medium in the pipeline does not flow out. The breathing valve plays the role of the last barrier and critical point in the working link. Automatically realize the breathing function.

[0039] In some embodiments, the valve flap assembly 2 also includes a cover plate 25, which is connected to the valve flap body 21, and the first seal 24 includes a soft sealing material. The first seal 24 is arranged between the cover plate 25 and the valve flap body 21, and the first seal 24 includes an exposed portion 240 protruding from the cover plate 25 and the valve flap body 21. In the closed state, the exposed portion 240 of the first seal 24 is pressed against the inner wall of the valve body 1.

[0040] By setting the first seal 24 to be a soft sealing material, a higher sealing effect can be achieved. At the same time, since the first seal 24 is also provided with an exposed portion 240, when the valve flap assembly 2 moves close to the sealing seat 11 of the valve body 1 and docks, the exposed portion 240 of the first seal 24 directly abuts against the sealing seat 11. Since the first seal 24 is a soft sealing material, it can play a buffering role, preventing the cover plate 25 or the valve flap body 21 from directly impacting and colliding with the sealing seat 11 of the valve body 1 to generate sparks and static electricity, preventing fire and explosion, and improving the safety performance of the breathing valve.

[0041] Specifically, the soft sealing material includes PTFE or nylon.

[0042] For a medium that is not flammable or explosive, such as water, the first sealing member 24 may also be made of a hard sealing material.

[0043] In some embodiments, the cover plate 25 includes a cover plate 25 body and a clamping edge arranged on the outer wall of the cover plate 25 body, the first seal 24 includes a seal body and a sealing edge arranged on the outer wall of the seal body, the seal body is fixed between the cover plate 25 body and the end face of the valve flap body 21, and the sealing edge is fixed between the clamping edge of the cover plate 25 and the outer wall of the valve flap body 21.

[0044] Specifically, in some embodiments, the cover plate 25 body is cylindrical, the pressing edge is arranged on the outer peripheral wall of the cover plate 25 body, and the pressing edge extends along the axial direction of the cover plate 25 body. The seal body is annular, the sealing edge is arranged on the outer peripheral wall of the seal body, and the sealing edge extends along the axial direction of the seal body. The seal body of the first seal 24 abuts between the end face of the cover plate 25 body and the valve flap body 21, and the sealing edge of the first seal 24 abuts between the pressing edge of the cover plate 25 and the outer wall of the valve flap body 21. Through such a structural setting, the cover plate 25 can wrap most of the first seal 24, ensure that the first seal 24 is fully tightened, and then ensure the sealing effect between the valve flap assembly 2 and the valve body 1.

[0045] In some embodiments, the cover plate 25 and the valve flap body 21 are connected via a first fastener 27 , and the first fastener 27 passes through the first sealing member 24 .

[0046] Specifically, the cover plate 25 and the first sealing member 24 are both provided with through holes that cooperate with each other, and the valve flap body 21 is provided with a threaded hole, and the first fastener 27 passes through the cover plate 25 and the first sealing member 24 in sequence, and is finally tightened in the threaded hole of the valve flap body 21. This arrangement can ensure that the first sealing member 24 is fully tightened.

[0047] In some embodiments, a sealing surface of the sealing seat 11 facing the delivery cavity 12 is provided with a hard sealing layer 16 , and in a closed state, the first sealing member 24 abuts against the hard sealing layer 16 for sealing.

[0048] By providing a hard sealing layer 16 on the sealing surface of the sealing seat 11 and using the hard sealing layer 16 and the first sealing member 24 to abut and seal, the sealing performance between the valve flap assembly 2 and the valve body 1 can be further improved. At the same time, the hard sealing layer 16 is also wear-resistant and can increase the service life of the breathing valve.

[0049] Specifically, the hard sealing layer 16 includes carbon steel, stainless steel or hard alloy for overlay welding.

[0050] In some embodiments, a threaded section is provided at the upstream end of the valve stem 22, and an adjusting nut 28 is connected to the threaded section. A limiting sleeve 29 is sleeved on the valve stem 22, and the limiting sleeve 29 includes a cylinder body and a limiting ridge. The elastic reset member 23 abuts between the sealing seat 11 and the limiting ridge, and the upstream end of the limiting sleeve 29 abuts against the adjusting nut 28.

[0051] The upstream end of the valve stem 22 is located in the suction chamber 13 .

[0052] Specifically, the elastic reset member 23 includes a spring, which is sleeved on the valve stem 22, and the two ends of the spring abut between the sealing seat 11 and the limiting convex edge. By setting the adjusting nut 28 and the limiting sleeve 29 and changing the fastening position of the adjusting nut 28, the spacing between the limiting sleeve 29 and the sealing seat 11 can be changed, thereby adjusting the compression amount of the spring, adjusting the preload torque of the spring, that is, adjusting the opening pressure of the valve disc assembly 2. It can be adjusted according to different pipeline pressures and breathing check function requirements to achieve the common use of valves in different breathing conditions.

[0053] Furthermore, a locking plate 26 is provided between the adjusting nut 28 and the valve stem 22. By providing the locking plate 26, a locking connection between the adjusting nut 28 and the valve stem 22 can be ensured. Specifically, the locking plate 26 includes a GB / T855 double-ear brake washer.

[0054] Since the valve stem 22 constitutes a long guide handle, it plays a guiding role in the movement of the valve flap assembly 2. At the same time, the valve stem 22 can cooperate with the adjustment limit sleeve 29 to set different spring forces.

[0055] In the fields of nuclear power and petrochemicals, since pipelines may transport toxic, harmful, flammable and explosive media, high requirements are placed on the external sealing performance of valves. Current breathing valves have media leakage.

[0056] To solve this technical problem, in some embodiments, a valve cover 3 is further included, the upstream end of the valve cover 3 is connected to the valve body 1 , and the valve cover 3 and the valve body 1 are sealed via a second sealing member 4 .

[0057] The valve cover 3 and the valve body 1 are sealed and connected via the second sealing member 4, which can prevent the medium in the delivery chamber 12 of the breathing valve from leaking outward.

[0058] Specifically, in some embodiments, the valve cover 3 has a step, the step of the valve cover 3 is butted against the radial end face of the valve body 1, and the second sealing member 4 is located between the step of the valve cover 3 and the radial end face of the valve body 1. Further, there is a surrounding installation cavity between the step of the valve cover 3 and the radial end face of the valve body 1, and the second sealing member 4 is arranged in the installation cavity. Further, in this embodiment, an annular groove is provided on the radial end face of the valve body 1, and the second sealing member 4 is arranged in the annular groove. Further, the upstream end of the valve cover 3 and the downstream end of the valve body 1 are threadedly connected, and are spot-welded on the outer peripheral wall to achieve an anti-loosening effect.

[0059] The connection between the valve cover 3 and the valve body 1 is a full threaded connection, which saves space and has a compact structure. The thread is only used for fastening, and finally spot welding is added on the outside to achieve relative fixation between the various parts of the valve.

[0060] Specifically, the second sealing ring includes an O-ring.

[0061] In some embodiments, the downstream end of the valve cover 3 has an adapting connection structure 31 suitable for connecting to a pipeline, and the adapting connection structure 31 includes a threaded connection structure, a flange connection structure or a plug-in connection structure.

[0062] The downstream end of the valve cover 3 can be connected to a pipeline. According to the different structures of different pipelines, the downstream end of the valve cover 3 can be set to a matching adapter connection structure 31. In this way, when connecting pipelines of different structures, an adaptive valve cover 3 can be used.

[0063] In some embodiments, a filter assembly 5 is also included, and the filter assembly 5 includes a mounting base 51 and a filter basket 52. The mounting base 51 is connected to the upstream end of the valve body 1; the filter basket 52 is connected to the mounting base 51 through a connecting piece 53, the inner cavity of the filter basket 52 is connected to the suction cavity 13, and one end of the valve stem 22 extends into the filter basket 52.

[0064] By providing the filter assembly 5 and connecting the filter assembly 5 to the upstream end of the valve body 1, the medium will be filtered by the filter basket 52 before entering the suction chamber 13, preventing large particles of impurities in the medium such as diesel from entering the delivery chamber 12, thereby ensuring the operating performance of the machine.

[0065] Furthermore, the mounting base 51 includes a mounting tube and a mounting flange arranged on the outer wall of the mounting tube. The mounting flange is provided with a through hole, and the upstream end of the valve body 1 connected thereto is provided with a threaded hole. The mounting base 51 is connected to the valve body 1 through a second fastener 54.

[0066] The connecting member 53 includes a connecting tube and a connecting flange provided on the outer periphery of the connecting tube, the connecting tube is threadedly connected to the mounting tube of the mounting base 51, and the outer periphery of the connecting tube and the mounting flange of the mounting base 51 are welded around a circle. The outer ring of the filter basket 52 and the connecting flange of the connecting member 53 are welded around a circle.

[0067] The filter assembly 5 adopts a combination of thread fastening and surrounding welding, which saves space, simplifies the valve structure, and makes the decoupling stock compact. At the same time, since the filter basket 52 has a certain depth, it provides sufficient activity space for the valve flap assembly 2 to move up and down.

[0068] When there is diesel in the pipeline, it carries a certain pressure. After the diesel is used, the pressure decreases, the breathing valve opens, and the diesel in the diesel tank is transported through the filter assembly 5.

[0069] The utility model can ensure that the pipeline is filled with diesel of corresponding pressure in real time according to pipeline demand, and at the same time ensure that diesel will not be transported further after there is diesel in the pipeline, thereby realizing automatic control of the valve without external force driving; and the inside of the valve body 1 realizes non-return sealing through soft sealing material; the utility model is compact and small, has a high sealing performance level and a long service life.

[0070] In some embodiments, the outer periphery of the downstream end of the valve cover 3 has at least two torque transmission surfaces 32, and the torque transmission surfaces 32 are convenient for torque transmission connection with a torque transmission tool.

[0071] By providing at least two torque transmission surfaces 32 on the outer periphery of the downstream end of the valve cover 3 , the torque transmission tool can be easily matched with the valve cover 3 , thereby facilitating the installation of the valve cover 3 .

[0072] for Figure 1 The breathing valve provided in the embodiment shown has the following installation steps:

[0073] The various parts of the filter assembly 5 are assembled and welded: the filter basket 52 and the connecting piece 53 are connected by welding, and then the connecting piece 53 and the mounting base 51 are screwed together to obtain the following: Figure 5 The structure shown.

[0074] The first sealing member 24 is installed into the cover plate 25, and bolts are inserted into the reserved through holes of the cover plate 25 and the first sealing member 24, and then the cover plate 25 and the first sealing member 24 are tightened and connected to the valve flap body 21 to form the valve flap assembly 2. Figure 2 The structure shown.

[0075] The valve disc assembly 2 is inserted into the valve body 1. After the spring is installed, the limiting sleeve 29 is screwed into the upstream end thread of the valve stem 22, and then the locking plate 26 and the nut are screwed into the valve stem 22 in sequence. According to the required breathing opening and closing pressure, the position of the limiting sleeve 29 and the nut is adjusted so that the spring reaches the predetermined spring force, and then the locking plate 26 is locked.

[0076] The filter assembly 5 is fastened to the upstream end of the valve body 1 by bolts.

[0077] Install the second sealing member 4 into the annular groove of the valve body 1, screw the valve cover 3 into the downstream end of the valve body 1 through the threaded structure, press the second sealing member 4, and after the sealing effect is achieved, spot weld the valve cover 3 and the valve body 1 to prevent loosening.

[0078] At this point, the breathing valve is completely assembled.

[0079] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A breathing valve, characterized in that: include: A valve body (1), wherein the valve body (1) has a delivery chamber (12) suitable for communicating with a pipeline and a suction chamber (13) suitable for communicating with a medium source; A valve flap assembly (2), the valve flap assembly (2) being movably arranged in the valve body (1), the valve flap assembly (2) comprising a valve flap body (21) and a first sealing member (24) arranged on the valve flap body (21), the first sealing member (24) being adapted to abut against and seal against the inner wall of the valve body (1); the valve flap assembly (2) having a closed state in which it abuts against and seals against the inner wall of the valve body (1) and an open state in which it is separated from the inner wall of the valve body (1); When the pressure of the delivery chamber (12) is lower than the pipeline design pressure, the valve flap assembly (2) is in an open state, the delivery chamber (12) and the suction chamber (13) are connected, and the delivery chamber (12) sucks in the medium; When the pressure of the delivery chamber (12) is greater than or equal to the pipeline design pressure, the valve flap assembly (2) is in a closed state, the delivery chamber (12) and the suction chamber (13) are blocked, and the medium is prevented from flowing back.

2. The breathing valve according to claim 1, characterized in that: The inner wall of the valve body (1) is provided with a sealing seat (11), and the sealing seat (11) divides the valve body (1) into the delivery chamber (12) and the suction chamber (13); the sealing seat (11) has a mounting hole (14) and a flow channel hole (15); The valve flap assembly (2) is arranged in the mounting hole (14), and the valve flap assembly (2) also includes a valve stem (22). The valve flap body (21) is located in the delivery chamber (12), one end of the valve stem (22) is connected to the valve flap body (21), and the other end of the valve stem (22) passes through the mounting hole (14) and extends into the suction chamber (13); in the open state, the delivery chamber (12) and the suction chamber (13) are connected through the flow channel hole (15).

3. The breathing valve according to claim 2, characterized in that: The valve flap assembly (2) further comprises an elastic return member (23), which is arranged in the suction chamber (13) and connected between the valve stem (22) and the sealing seat (11); the elastic return member (23) is suitable for applying an elastic force from the conveying chamber (12) to the suction chamber (13) to the valve stem (22).

4. The breathing valve according to any one of claims 1 to 3, characterized in that: The valve flap assembly (2) also includes a cover plate (25), wherein the cover plate (25) is connected to the valve flap body (21), and the first sealing member (24) includes a soft sealing material. The first sealing member (24) is arranged between the cover plate (25) and the valve flap body (21), and the first sealing member (24) includes an exposed portion (240) protruding from the cover plate (25) and the valve flap body (21). In the closed state, the exposed portion (240) of the first sealing member (24) is pressed against the inner wall of the valve body (1).

5. The breathing valve according to claim 4, characterized in that: The cover plate (25) includes a cover plate (25) body and a clamping edge arranged on the outer wall of the cover plate (25) body, the first seal (24) includes a seal body and a sealing edge arranged on the outer wall of the seal body, the seal body is fixed between the cover plate (25) body and the end face of the valve flap body (21), and the sealing edge is fixed between the clamping edge of the cover plate (25) and the outer wall of the valve flap body (21).

6. The breathing valve according to claim 2 or 3, characterized in that: The sealing surface of the sealing seat (11) facing the conveying cavity (12) is provided with a hard sealing layer (16), and in the closed state, the first sealing member (24) abuts against the hard sealing layer (16) for sealing.

7. The breathing valve according to claim 3, characterized in that: The upstream end of the valve stem (22) is provided with a threaded section, and the threaded section is connected to an adjusting nut (28). A limiting sleeve (29) is sleeved on the valve stem (22), and the limiting sleeve (29) includes a cylinder body and a limiting convex edge. The elastic reset member (23) abuts between the sealing seat (11) and the limiting convex edge, and the upstream end of the limiting sleeve (29) abuts against the adjusting nut (28).

8. The breathing valve according to any one of claims 1 to 3, characterized in that: It also comprises a valve cover (3), the upstream end of the valve cover (3) is connected to the valve body (1), and the valve cover (3) and the valve body (1) are sealed via a second sealing member (4).

9. The breathing valve according to claim 8, characterized in that: The downstream end of the valve cover (3) has an adaptable connection structure (31) suitable for connection with a pipeline, and the adaptable connection structure (31) includes a threaded connection structure, a flange connection structure or a plug-in connection structure.

10. The breathing valve according to claim 2 or 3, characterized in that: The valve body (22) further comprises a filter assembly (5), wherein the filter assembly (5) comprises a mounting base (51) and a filter basket (52), wherein the mounting base (51) is connected to the upstream end of the valve body (1); the filter basket (52) is connected to the mounting base (51) via a connecting piece (53), the inner cavity of the filter basket (52) is connected to the suction cavity (13), and one end of the valve stem (22) extends into the filter basket (52).

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