CN115183035A - Back pressure valve - Google Patents

Abstract

The invention belongs to the technical field of valves and discloses a back pressure valve. The back pressure valve includes a valve seat, a valve cover, a valve core assembly and an adjustment assembly; an inlet channel and an outlet channel connecting the inner and outer walls are respectively opened on the side wall of the valve seat; the valve cover is installed in cooperation with the valve seat, and forms an empty space with the valve seat. cavity; the valve core assembly is installed inside the valve seat, and divides the cavity into a first accommodating cavity and a second accommodating cavity, the valve core assembly can block the first port of the outlet channel away from the outer wall of the valve seat; the adjustment assembly is located in the second accommodating cavity The accommodating cavity, the adjustment assembly includes a coaxially arranged elastic piece and a first limiting piece, the first limiting piece is fitted between the inner sidewall surfaces of the valve cover, and the inner sidewall surface of the bonnet restricts the non-axial movement of the first limiting piece Trend; the first limiting member includes a first limiting structure, one end of the elastic member is connected to the valve core assembly, and the other end is fixedly connected to the first limiting structure. The back pressure valve has the advantages of simple structure, convenient maintenance, low manufacturing cost, high adjustment precision and high reliability.

Description

a back pressure valve

technical field

The invention relates to the technical field of valves, in particular to a back pressure valve.

Background technique

The back pressure valve is a valve element that adjusts the pressure in the pipeline. The back pressure valve can maintain the pressure required by the pipeline and enable the pump to output flow normally when the pressure of the pipeline or equipment container is unstable. .

The back pressure valve works by the elastic force of the spring. When the system pressure is smaller than the set pressure, the diaphragm blocks the pipeline under the action of the spring force: when the system pressure is greater than the set pressure, the diaphragm compresses the spring to make the pipeline connect. through the back pressure valve.

The existing back pressure valve has the problem of poor pressure adjustment accuracy, and cannot be used in some systems that require high pressure setting accuracy.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a back pressure valve, which has the advantages of simple structure, convenient maintenance, low manufacturing cost, high adjustment precision and high reliability.

For this purpose, the present invention adopts the following technical solutions:

The back pressure valve includes a valve seat, a valve cover, a valve core assembly and an adjustment assembly; an inlet channel and an outlet channel connecting the inner and outer walls are respectively opened on the side wall of the valve seat; the valve cover is installed in cooperation with the valve seat, and forms an empty space with the valve seat. cavity; the valve core assembly is installed inside the valve seat, and divides the cavity into a first accommodating cavity and a second accommodating cavity, the valve core assembly can block the first port of the outlet channel away from the outer wall of the valve seat; the adjustment assembly is located in the second accommodating cavity The accommodating cavity, the adjustment assembly includes a coaxially arranged elastic piece and a first limiting piece, the first limiting piece is fitted between the inner sidewall surfaces of the valve cover, and the inner sidewall surface of the bonnet restricts the non-axial movement of the first limiting piece Trend; the first limiting member includes a first limiting structure, one end of the elastic member is connected to the valve core assembly, and the other end is fixedly connected to the first limiting structure.

Optionally, the first limiting structure is a first limiting boss and/or a first limiting groove, and the sidewall surface of the elastic member abuts against the first limiting structure.

Optionally, the adjustment assembly further includes a second limiting member coaxial with the elastic member, the lower wall surface of the second limiting member is fixedly connected to the valve core assembly, the second limiting member includes a second limiting structure, the second limiting member is The bit structure is fixedly connected to the elastic piece.

Optionally, the second limiting structure includes a second limiting boss, and the second limiting boss is inserted into the elastic member.

Optionally, the second limiting structure includes a limiting sidewall surrounding the outer edge of the second limiting member, and an inner sidewall surface of the limiting sidewall abuts against the outer side of the elastic member.

Optionally, it also includes an adjustment piece, the upper part of the valve cover is provided with an installation hole, the adjustment piece is inserted into the installation hole, the lower end of the adjustment piece abuts on the first limit piece, and can push the first limit piece to slide, so that the The first limit piece is close to or away from the valve core assembly.

Optionally, the adjustment member is a screw, the installation hole is a threaded hole, and the adjustment member is threadedly connected to the installation hole.

Optionally, the valve core assembly includes an elastic diaphragm and a valve core body, the elastic diaphragm divides the cavity into a first accommodating cavity and a second accommodating cavity, the valve core body is installed on the lower wall surface of the elastic diaphragm, and the bottom of the valve core body is used for sealing. Block the first port.

Optionally, the bottom of the valve core body is provided with an elastic seal.

Optionally, a mounting boss is protruded from the lower wall surface of the elastic diaphragm.

Optionally, the valve cover is provided with a pressure relief through hole, and the inside of the valve cover communicates with the external atmosphere through the pressure relief through hole.

Optionally, fittings are installed on both the inlet channel and the outlet channel.

Beneficial effects:

The back pressure valve divides the cavity of the back pressure valve into a first accommodating cavity and a second accommodating cavity by using a valve core assembly, and an adjustment assembly is arranged in the second accommodating cavity, and the adjustment assembly includes a coaxially arranged elastic member and a first accommodating cavity. Limiting piece, the first limiting piece includes a first limiting structure, and the first limiting structure is fixed on the elastic piece, which can limit the elastic piece and prevent the elastic piece from appearing axis deviation or tilting phenomenon. The back pressure valve can ensure that the axis of its internal elastic member will not be offset or inclined when it is pressurized, so that the pressure value of the back pressure valve when it is opened by the fluid pressure is always the calibration value or the preset value, which improves the back pressure valve. Accuracy and reliability, and also have the advantages of simple structure, convenient maintenance and low manufacturing cost.

Description of drawings

1 is an axonometric view of a back pressure valve provided by a specific embodiment of the present invention;

2 is an exploded view of a back pressure valve provided by a specific embodiment of the present invention;

3 is a cross-sectional view of a back pressure valve provided by a specific embodiment of the present invention;

FIG. 4 is a schematic diagram of the valve core assembly installed on the valve seat in this embodiment;

FIG. 5 is a schematic diagram of the comparison between the specific embodiment of the present invention and the state of the elastic member in the prior art when the elastic member is compressed.

In the picture:

10. The first accommodating cavity; 20. The second accommodating cavity; 30. The joint;

100, valve seat; 110, inlet channel; 120, outlet channel; 121, first port; 130, installation groove;

200, valve cover; 210, installation hole; 220, pressure relief through hole; 230, installation part;

310, elastic diaphragm; 311, installation boss; 312, annular rib; 320, valve core body; 321, elastic seal; 322, annular groove;

410, elastic piece; 420, first limit piece; 421, guide part; 422, first limit boss; 423, guide side wall; 430, second limit piece; 431, second limit boss; 432, the limit side wall; 441, the adjustment piece; 442, the installation nut.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, the drawings only show some but not all structures related to the present invention.

In the description of the present invention, unless otherwise expressly specified and limited, the terms "connected", "connected" and "fixed" should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integrated ; It can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific conditions.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may include the first and second features in direct contact, or may include the first and second features Not directly but through additional features between them. Also, the first feature being "above", "over" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature is "below", "below" and "below" the second feature includes the first feature being directly below and diagonally below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this embodiment, the terms "upper", "lower", "right", etc. are based on the orientation or positional relationship shown in the accompanying drawings, which are only for convenience of description and simplified operation, rather than indicating Or imply that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention. In addition, the terms "first" and "second" are only used for distinction in description, and have no special meaning.

Referring to FIG. 1, the back pressure valve includes a valve seat 100 and a valve cover 200. The valve cover 200 is detachably mounted on the valve seat 100. Specifically, the valve cover 200 is threadedly connected to the valve seat 100, and the valve cover 200 is provided with The installation part 230 is two notches oppositely arranged on the side wall surface of the valve cover 200, and an installation tool (such as a wrench, pliers, etc.) The valve cover 200 is screwed and fixed on the valve seat 100 .

Specifically, as shown in FIG. 2 and FIG. 3 , in this embodiment, the back pressure valve includes a valve seat 100 , a valve cover 200 , a valve core assembly and an adjustment assembly; an inlet channel 110 and an outlet are relatively opened on the side wall of the valve seat 100 . The channel 120; the bottom of the valve cover 200 is installed on the top of the valve seat 100, and forms a cavity with the valve seat 100; the valve core assembly is installed inside the valve seat 100, and the cavity is divided into a first accommodating cavity 10 and a second accommodating cavity 20. The valve core assembly can block the first port 121 of the outlet passage 120 that is far away from the outer wall of the valve seat 100;

The adjustment assembly is located in the second accommodating cavity 20. The adjustment assembly includes a coaxially arranged elastic member 410 and a first limiting member 420. The first limiting member 420 includes a guide portion 421 arranged up and down and a first limiting structure. The limiting structure is a first limiting boss 422 and/or a first limiting groove; one end of the elastic member 410 is drivingly connected with the valve core assembly, and the other end abuts against the first limiting member 420 . In this embodiment, the elastic member 410 is selected as a spring, and the elastic modulus of the spring is determined by the preset pressure calibrated by the back pressure valve. Those skilled in the art can determine the elastic modulus of the spring according to the preset pressure. The amount, length and material are not specifically limited in this embodiment.

In this embodiment, the guide portion 421 of the first limiting member 420 is installed between the inner sidewall surfaces of the valve cover 200 . Under the limitation of the inner sidewall surface of the valve cover 200 , the tendency of the first limiting member 420 to move non-axially is reduced. Restriction, specifically, taking the perspective shown in FIG. 3 as an example, the axial movement of the first limiting member 420 is the movement in the direction of compressing the spring or releasing the spring, and the trend of non-axial movement mainly refers to the first limiting member 420 420 tends to move in the horizontal direction. Since the top of the spring is connected to the first limiting member 420, the movement of the first limiting member 420 in the horizontal direction will cause the spring to be offset, thereby affecting the preset pressure of the spring on the valve core assembly, which will The accuracy of the back pressure valve is affected, so in this embodiment, the gap between the outer peripheral side wall of the first limiting member 420 and the inner side wall of the valve cover 200 is set to be ≤0.5 mm, specifically 0 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.4 mm mm, 0.5 mm, etc., so that the limit formed by the inner side wall of the valve cover 200 on the first limiting member 420 can basically avoid the occurrence of the spring deflection caused by the horizontal movement.

When the first limiting structure is the first limiting boss 422 , as shown in FIG. 3 , the elastic member 410 , that is, the top inner ring of the spring can be sleeved on the first limiting boss 422 , thereby making the first limiting boss 422 . The position boss 422 forms a position limit for the elastic member 410; when the first position limit structure is a position limit groove, the position limit groove can be an annular groove body opened on the lower wall of the first position limit member 420, and the annular groove body In accordance with the size of the top ring of the spring, the top of the spring is embedded in the annular groove body to form a limit. The limit groove can also be formed by the guide side wall 423 surrounding the outer edge of the guide portion 421. At this time, the top of the spring is inserted between the inner walls of the guide side wall 423;

Preferably, when the guide side wall 423 is surrounded by the outer edge of the guide portion 421, the gap between the outer peripheral side wall surface of the guide side wall 423 and the inner side wall surface of the valve cover 200 should be as small as possible. 0.5mm, the guide side wall 423 set in this way can prevent the first limiter 420 from being displaced in the horizontal direction when the first limiter 420 is pushed, and can stably move in the axial direction. When adjusting the back pressure valve When the preset starting pressure is set, the precision of its adjustment will not be reduced, and the reliability of its use can still be maintained after multiple adjustments.

The back pressure valve divides the cavity of the back pressure valve into a first accommodating cavity 10 and a second accommodating cavity 20 by using a spool assembly. The second accommodating cavity 20 is provided with an adjustment assembly, and the adjustment assembly includes a coaxially arranged elastic member 410 and the first limiting member 420, the first limiting member 420 includes a first limiting structure, and the first limiting structure is fixedly connected with the elastic member 410, which can limit the elastic member 410 and prevent the elastic member 410 The phenomenon of axis deviation or inclination occurs under pressure; at the same time, the first limiting member 420 is limited by the inner side wall of the valve cover 200, so that the installation of the first limiting member 420 and the second accommodating chamber 20 is more stable, The deflection of the first limiting member 420 is prevented when it is pressed. The back pressure valve can ensure that the axis of the inner elastic member 410 is not offset or inclined when it is pressurized, so that the pressure value of the back pressure valve when it is opened by the fluid pressure is always the calibrated preset pressure value, which improves the back pressure valve. It also has the advantages of simple structure, convenient maintenance and low manufacturing cost.

In this embodiment, the valve cover 200 is provided with a pressure relief through hole 220 , and the second accommodating chamber 20 communicates with the outside atmosphere through the pressure relief through hole 220 . This is because when the valve core assembly moves under pressure, the volume of the second accommodating cavity 20 will decrease, and the pressure relief through hole 220 communicates the second accommodating cavity 20 with the atmosphere, which can prevent the second accommodating cavity 20 from generating air pressure. On the spool assembly, specifically acting on the elastic diaphragm 310 of the spool assembly, it ensures that the set pressure of the back pressure valve is the force exerted by the deformation of the elastic member 410 on the spool assembly, which improves the performance of the back pressure valve. precision.

As shown in FIG. 3 , the adjustment assembly further includes a second limiting member 430 coaxial with the elastic member 410 , the lower wall surface of the second limiting member 430 is in contact with the valve core assembly, and a second limiting member 430 is provided with a second limiting member 430 . Two limiting structures, the second limiting structure is fixedly connected to the elastic member 410 . In this embodiment, the second limiting structure includes a second limiting boss 431 protruding from the second limiting member 430 , and the second limiting boss 431 is inserted into the elastic member 410 . More specifically, The second limiting boss 431 is in an interference fit with the elastic member 410 , that is, the inner ring of the bottom of the spring. Therefore, the second limiting boss 431 of the second limiting member 430 can further fix the lower end of the elastic member 410 to avoid The possible deflection of the spring, the deflection of the bottom, and the deflection of the spring appear, which further improves the accuracy of the back pressure valve.

Optionally, the second limiting structure includes a limiting sidewall 432 surrounding the outer edge of the second limiting member 430 , the inner sidewall surface of the limiting sidewall 432 abuts against the outer side of the elastic member 410 , and the limiting sidewall 432 432 can further fix the lower end of the elastic member 410, avoid possible deviation and falling off of the bottom of the spring, and further improve the accuracy of the back pressure valve; in this embodiment, the outer wall surface of the second limiting member 430 and the valve cover The inner wall surface of 200 has a certain interval, and the interval is 1mm to 5mm. The smaller the interval, the better. The reason is that the small interval can ensure that the bottom surface of the second stopper 430 is set larger, which can make the second stopper 430 larger. The contact area between 430 and the valve core assembly is as large as possible, preventing uneven deformation of the valve core assembly when it is stressed, stabilizing the movement of the valve core assembly, the elastic diaphragm 310 and the second limiting member 430, and ensuring the back pressure valve If the interval is too small, the second limiting member 430 will contact the inner wall surface of the valve cover 200 to generate friction and affect the accuracy of the back pressure valve. Therefore, the interval is designed to be ≥1mm. In this embodiment, the interval is set to 1mm. Not only can the second limiting member 430 and the elastic diaphragm 310 have a sufficiently large contact area, but also can prevent the second limiting member 430 from rubbing against the inner wall of the valve cover 200 when moving, ensuring that the valve core assembly The force of the fluid in the first accommodating chamber 10 can be effectively fed back to the elastic member 410, which improves the precision of the back pressure valve.

Please continue to refer to FIG. 2 and FIG. 3 , in this embodiment, an adjusting member 441 is further included. The upper portion of the valve cover 200 is provided with a mounting hole 210 , the adjusting member 441 is inserted into the mounting hole 210 , and the lower end of the adjusting member 441 abuts against the first mounting hole 210 . A limiting member 420 can push the first limiting member 420 to move, so that the first limiting member 420 is close to or away from the valve core assembly. In this embodiment, the adjusting member 441 is a screw, the mounting hole 210 is a threaded hole, and the adjusting member 441 is threadedly connected to the mounting hole 210 . Optionally, the adjusting member 441 is a screw, and a mounting nut 442 may also be provided above the mounting hole 210 , and the screw is threadedly connected to the mounting nut 442 . By twisting the screw, the screw can move up and down along the mounting hole 210, so that the guide portion 421 moves up and down, thereby adjusting the preset compression amount of the elastic member 410, changing the preset starting pressure of the back pressure valve, so that the back pressure The valve can meet the user's different pressure regulation needs. After the adjustment member 411 is adjusted to a suitable position, screw the nut 442 until the nut 422 abuts against the mounting hole 210, which is helpful for further fixing the position of the adjustment member 411. Therefore, the preset starting pressure of the back pressure valve is prevented from being affected by the position change of the adjusting member 411 .

Please continue to refer to FIG. 3 , both the inlet channel 110 and the outlet channel 120 are provided with the joint 30 . The joint 30 can conveniently install the back pressure valve in the air circuit that needs to adjust the pressure.

Optionally, the valve core assembly includes an elastic diaphragm 310 and a valve core body 320 , the elastic diaphragm 310 is installed inside the valve seat 100 , the valve core body 320 is installed on the lower wall of the elastic diaphragm 310 , and an elastic seal is provided at the bottom of the valve core body 320 321 , the elastic seal 321 can abut against the first port 121 . In this embodiment, the elastic diaphragm 310 separates the cavity formed after the valve cover 200 and the valve seat 100 are installed together into the first accommodating cavity 10 and the second accommodating cavity 20 . Preferably, in this embodiment, the outer edge of the elastic diaphragm 310 is connected to the The inner sidewall of the valve seat 100 is an interference fit, thereby ensuring sealing.

As shown in FIG. 4 , in order to further ensure the tightness of the elastic diaphragm 310 separating the first accommodating cavity 10 and the second accommodating cavity 20 , an annular rib 312 is protruded on the lower wall of the elastic diaphragm 310 , and the annular rib 312 is provided on the elastic diaphragm 310 The purpose of the middle part of the lower wall surface of the diaphragm 310 is to abut with the upper wall surface of the valve core body 320 to increase the sealing performance. Further, the upper wall surface of the valve core body 320 may be provided with an annular groove 322 fitted with the annular convex rib 312 . Further, the annular rib 312 is connected with the annular groove 322 by interference fit, and a plurality of annular rib 312 and the annular groove 322 are provided in one-to-one correspondence, three in this embodiment.

A stepped protrusion is formed on the inner wall surface of the valve seat 100 corresponding to the lower part of the elastic diaphragm 310 . After the valve cover 200 is installed with the valve seat 100 , the outer ring of the lower wall surface of the elastic diaphragm 310 is in contact with the stepped protrusion. In the example, an annular mounting boss 311 is protruded from the edge of the lower wall surface of the elastic diaphragm 310. When the valve cover 200 is installed with the valve seat 100, taking the installation method of screw connection as an example, usually the valve cover 200 will contact the elastic The outer edge of the diaphragm 310. During the tightening process, the valve cover 200 squeezes the upper wall of the elastic diaphragm 310. When the installation is finally completed, the valve cover 200 will squeeze the outer edge of the elastic diaphragm 310. At this time, the elastic diaphragm 310 may appear up and down. The wall surface is slightly wrinkled or deformed by the frictional force, which may cause a gap between the outer edge of the elastic diaphragm 310 and the inner side wall of the valve seat 100, which affects the sealing performance. The edge structure, on the other hand, can avoid the impact of gaps on sealing in such cases;

Further, in this embodiment, the upper surface of the stepped protrusion on the inner wall of the valve seat 100 corresponds to the mounting boss 311, and a mounting groove 130 is recessed downward, and the shape of the mounting groove 130 corresponds to the shape of the mounting boss 311. During the tightening and installation of the valve cover 200 and the valve seat 100, the bottom surface of the valve cover 200 will press the outer edge of the elastic diaphragm 310, so that the mounting boss 311 is pressed into the mounting groove 130 on the valve seat 100, thereby , under the guide limit of the installation groove 130, the deformation tendency of the elastic diaphragm 310 can be reduced, and the sealing effect can be improved; further, the installation boss 311 can be interfered with the installation groove 130 to strengthen the sealing effect. .

The elastic sealing member 321 can ensure that the valve core body 320 has a better sealing effect on the first port 121. In this embodiment, the elastic sealing member 321 is a rubber block, and can also be an elastic structure of other materials. The lower wall surface of the main body 320 corresponds to the position of the first port 121, and there is an installation position. The upper part of the elastic sealing member 321 is embedded in the installation position, and the lower wall surface of the elastic sealing member 321 is in contact with the At the first port 121, the sealing performance is better to prevent liquid leakage.

Specifically, the elastic diaphragm 310 is provided with a through hole, more specifically, the through hole is provided in the middle of the elastic diaphragm 310, the second limiting member 430 is provided with a threaded hole coaxial with the through hole, and the valve core body 320 includes There is a threaded portion, and the threaded portion is fitted with the above-mentioned threaded hole, so that the valve core body 320 and the second limiting member 430 sandwich the elastic diaphragm 310 therebetween, so that the valve core body 320 and the second limiting member 430 are sandwiched between them. 430 is fixed on the elastic diaphragm 310, and the annular rib 322 arranged in the middle of the lower wall surface of the elastic diaphragm 310 cooperates with the upper wall surface of the valve core body 320, and then cooperates with the tightening connection of the threaded part to ensure the sealing of the middle position of the elastic diaphragm 310 sex.

The pressure regulating working process of the back pressure valve in this embodiment is described in detail below:

After the fluid flows into the first accommodating chamber 10 from the inlet channel 110, it can generate pressure on the elastic diaphragm 310. When the pressure reaches a preset value (ie, the pressure of the fluid in the first accommodating chamber 10 on the elastic diaphragm 310 and the elastic member 410 on the elastic diaphragm 310) The acting force of the diaphragm 310 is the same), the continuous increase of the fluid pressure will cause the elastic diaphragm 310 and the valve core body 320 to move up and compress the spring, thereby opening the first port 121, and the fluid can flow out from the outlet channel 120 to realize pressure relief or opening. The function of closing the pipeline; when the fluid pressure drops below the preset value, the spring pushes the diaphragm and the valve core body 320 to descend, and the first port 121 is blocked again.

Specifically, as shown in FIG. 5 , the back pressure valve in the prior art is shown on the right side of the figure. Since both ends of the spring are not fixed and limited, the structural members in the back pressure valve are subject to the changing fluid pressure. The spring will be offset, deflected, tilted, etc., so that the actual pressure of the spring on the elastic diaphragm 310 will deviate from the preset pressure, resulting in a decrease in the accuracy of the back pressure valve, and long-term use will cause the spring to be further offset. If it increases, the accuracy of the back pressure valve will be further reduced. The spring in this embodiment shown on the left side of the figure, when the spring is compressed, its two ends are respectively affected by the first limiting boss 422 and the second limiting boss 422 in the first limiting member 420 and the second limiting member 430 , respectively. Due to the fixed and limiting effect of the position boss 431, the spring will not be offset or inclined, so the back pressure valve in this embodiment can ensure that the axis of the inner elastic member 410 will not be offset or inclined when it is under pressure, so that the back pressure valve does not offset or tilt. The pressure value of the pressure valve when it is opened by the fluid pressure is always the preset value, which improves the accuracy and reliability of the back pressure valve.

After testing, compared with the existing back pressure valve, the back pressure valve in this embodiment can improve the accuracy and reliability from the following aspects:

1. Flow sensitivity: The flow rate will cause the set back pressure value to fluctuate. The existing back pressure valve fluctuates by more than 10%. The back pressure valve in this embodiment has a back pressure of 0-5L/min. The value fluctuation can be controlled within 3%;

2. The difference between the opening pressure value and the set back pressure value: the difference between the existing back pressure valve exceeds 20%, and the one in this embodiment can be controlled within 10%;

3. Adjustment stability: when the adjustment member 441 is adjusted, the existing back pressure valve will fluctuate in the back pressure value due to the shaking of the internal structure, while the back pressure valve in this embodiment will not fluctuate;

4. Long-term stability: After 1 million open/close tests, the back pressure value of the existing back pressure valve is reduced by about 30%, and the back pressure value of the back pressure valve in this embodiment is still within 5%. And after 30 million opening/closing tests, the back pressure value of the back pressure valve in this embodiment can still meet the accuracy within 5%; and the back pressure valve in the prior art can meet the long-term reliability of the accuracy of 5%. To meet the performance requirements, precision electronic components are generally used for coordination, such as a combination of pressure sensor + solenoid valve/proportional valve + control circuit, etc., which is costly, and the back pressure valve in this embodiment does not need to use electronic devices , Only the internal structure design can meet the long-term reliability requirements of accuracy, and effectively control the production cost.

Obviously, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the embodiments of the present invention. For those of ordinary skill in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. There is no need and cannot be exhaustive of all implementations here. Any modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (11)

1. A back pressure valve, comprising: a valve seat (100), the valve seat (100) is respectively provided with an inlet channel (110) and an outlet channel (120) communicating with the inner and outer walls; a valve cover (200), the valve cover (200) is installed in cooperation with the valve seat (100), and forms a cavity with the valve seat (100); A valve core assembly, the valve core assembly is installed inside the valve seat (100), and divides the cavity into a first accommodating cavity (10) and a second accommodating cavity (20), the valve core assembly can Blocking the first port (121) of the outlet channel (120) located at the first accommodating cavity (10); It is characterized in that it also includes: An adjustment assembly, the adjustment assembly is located in the second accommodating cavity (20), the adjustment assembly includes a coaxially arranged elastic member (410) and a first limiting member (420), the first limiting member ( 420) is fitted between the inner sidewall surfaces of the valve cover (200), and the inner sidewall surfaces of the valve cover (200) limit the tendency of the first limiting member (420) to move non-axially; the first limiting member (420) The position member (420) includes a first position limit structure, one end of the elastic member (410) is connected to the valve core assembly, and the other end is fixedly connected to the first position limit structure. 2. The back pressure valve according to claim 1, wherein the first limiting structure is a first limiting boss (422) and/or a first limiting groove, and the elastic member (410) ) of the sidewall surface abuts against the first limiting structure. 3. The back pressure valve according to claim 1, wherein the adjustment assembly further comprises a second limiting member (430) coaxial with the elastic member (410), the second limiting member The lower wall surface of (430) is fixedly connected to the valve core assembly, the second limiting member (430) includes a second limiting structure, and the second limiting structure is fixedly connected to the elastic member (410). 4. The back pressure valve according to claim 3, wherein the second limiting structure comprises a second limiting boss (431), and the second limiting boss (431) is inserted into the inside the elastic member (410). 5. The back pressure valve according to claim 3, wherein the second limiting structure comprises a limiting side wall (432) surrounding the outer edge of the second limiting member (430) , the inner side wall surface of the limiting side wall (432) is in contact with the outer side of the elastic member (410). 6 . The back pressure valve according to claim 1 , further comprising an adjusting member ( 441 ), a mounting hole ( 210 ) is formed in the upper part of the valve cover ( 200 ), and the adjusting member ( 441 ) is plugged in. 7 . In the mounting hole (210), the lower end of the adjusting member (441) abuts against the first limiting member (420), and can push the first limiting member (420) to slide, so that all the The first limiting member (420) is close to or away from the valve core assembly. 7 . The back pressure valve according to claim 6 , wherein the adjusting member ( 441 ) is a screw, the mounting hole ( 210 ) is a threaded hole, and the adjusting member ( 441 ) is connected to the mounting hole. 8 . (210) Threaded connection. 8. The back pressure valve according to any one of claims 1-7, wherein the valve core assembly comprises an elastic diaphragm (310) and a valve core body (320), and the elastic diaphragm (310) connects the The cavity is divided into a first accommodating cavity (10) and a second accommodating cavity (20), the valve core body (320) is mounted on the lower wall surface of the elastic diaphragm (310), and the valve core body (320) The bottom is used to block the first port (121). 9 . The back pressure valve according to claim 8 , wherein an elastic sealing member ( 321 ) is provided at the bottom of the valve core body ( 320 ). 10 . 10 . The back pressure valve according to claim 8 , wherein a mounting boss ( 311 ) is protruded on the lower wall surface of the elastic diaphragm ( 310 ). 11 . 11. The back pressure valve according to any one of claims 1-7, characterized in that, a pressure relief through hole (220) is opened on the valve cover (200), and the valve cover (200) passes through the inside of the valve cover (200). The pressure relief through hole (220) communicates with the outside atmosphere.

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