Lifting check valve with adjustable opening pressure

Abstract

The utility model relates to the technical field of valves, and discloses a lifting check valve with adjustable opening pressure, which comprises a valve body, a valve cover, a guide sleeve, a valve clack, an elastic piece, a base and a bolt, the guide sleeve is arranged in the valve body; a plurality of through holes are formed in the side wall of the guide sleeve in the axis direction of the guide sleeve; the valve clack is slidably arranged in the guide sleeve, and the bottom of the valve clack is suitable for blocking a valve body inner runner; the elastic piece and the base are arranged in the guide sleeve, one end of the elastic piece abuts against the valve clack, and the other end of the elastic piece abuts against the base. The elastic piece has elastic force for forcing the valve clack to block a flow channel in the valve body; a through hole is formed in the base; and the bolt is suitable for being inserted into the guide sleeve and the through hole in the base. According to the lifting check valve with the adjustable opening pressure, through the ingenious structural design, the opening pressure of the valve can be conveniently adjusted.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, specifically to an adjustable lifting check valve with adjustable opening pressure. Background Technology

[0002] Check valves, as key valves used to prevent backflow of media, are widely used in many industrial fields such as petroleum, chemical, power, and water supply and drainage, as well as in pipeline systems in daily life. Their working principle is based on the flow pressure of the media itself to open the valve, allowing forward flow. When the media shows a tendency to flow backward, the valve automatically closes to prevent reverse flow, thereby ensuring the safe and stable operation of the system.

[0003] Among the many types of check valves, lift check valves are commonly used due to their relatively simple structure and good sealing performance. A typical lift check valve mainly consists of a valve body, valve disc, valve cover, and spring. The spring plays a crucial role in the valve's operation, providing the closing force to the valve disc and ensuring that the valve disc can close quickly and tightly when the medium stops flowing forward or backflow occurs, preventing backflow.

[0004] However, a significant drawback of existing conventional lift check valves is that their spring force is not adjustable. In actual industrial production and various application scenarios, different operating conditions require different valve opening pressures. For example, in petrochemical plants, the required valve opening pressure may need to be adjusted accordingly as the process flow changes and the type and flow rate of the medium in the pipeline changes. Currently, when adjusting the valve opening pressure, it is often only possible to replace the spring with one of different spring forces. This method is not only cumbersome, requiring professional personnel for disassembly and installation, consuming a lot of time and labor costs, but also, in actual operation, due to the limited reserve of springs of different specifications, it may be impossible to find a perfectly compatible spring in time, leading to prolonged equipment downtime and seriously affecting production efficiency. In addition, frequent spring replacements may also cause wear and tear on other valve components, reducing the overall service life of the valve and increasing equipment maintenance costs.

[0005] In summary, existing conventional lift check valves have limited adaptability to complex and ever-changing operating conditions due to the non-adjustable spring force. There is an urgent need for a lift check valve that can easily and quickly adjust the spring force to meet the diverse needs of practical applications. Utility Model Content

[0006] In view of this, the present invention provides an adjustable lifting check valve with adjustable opening pressure to solve the problem of non-adjustable spring force in conventional lifting check valves.

[0007] This utility model provides an adjustable lifting check valve with adjustable opening pressure, comprising:

[0008] A valve body and a valve cover, wherein the valve cover is connected to the valve body;

[0009] A guide sleeve is disposed inside the valve body; several through holes are provided on the side wall of the guide sleeve along the axial direction of the guide sleeve.

[0010] A valve disc is slidably disposed inside the guide sleeve, and the bottom of the valve disc is adapted to block the flow channel inside the valve body;

[0011] An elastic element and a base are disposed inside the guide sleeve. One end of the elastic element abuts against the valve disc, and the other end of the elastic element abuts against the base. The elastic element has an elastic force that forces the valve disc to block the flow channel inside the valve body. The base is provided with a through hole.

[0012] A pin, which is adapted to be inserted into a through hole on the guide sleeve and the base.

[0013] Beneficial Effects: The valve cover is tightly connected to the valve body, and together they form the basic outline and enclosed space of the valve, providing stable support and protection for the normal operation of internal components. The valve body, as the main channel for media flow, has internal flow channels, while the valve cover seals and secures internal components, preventing media leakage and facilitating installation and maintenance. The guide sleeve is installed inside the valve body, its main function being to provide precise guidance for the movement of the valve disc, ensuring that the valve disc maintains stable linear movement during lifting and lowering, avoiding deviation or swaying, thereby ensuring the valve's sealing performance and reliability. Along the axial direction of the guide sleeve, its sidewalls have several through holes evenly distributed; these through holes play a crucial role in adjusting the valve's opening pressure. The elastic element and base are both located inside the guide sleeve. The elastic element is typically a spring, with one end tightly abutting against the valve disc and the other end firmly connected to the base. In its natural state, the elastic element possesses the elastic force to drive the valve disc to block the flow channels within the valve body, ensuring that the valve can quickly close when the media stops flowing forward or shows a backflow tendency. The base not only provides support for the elastic element but also has through holes on its surface corresponding to the through holes on the side wall of the guide sleeve. These holes are used to engage with a pin to adjust the compression of the elastic element. The pin, a key component for regulating valve opening pressure, is sized and shaped to match the through holes on the guide sleeve and the base. By inserting the pin into different combinations of through holes, the position of the base within the guide sleeve can be changed, thereby adjusting the compression of the elastic element and achieving flexible adjustment of the valve opening pressure.

[0014] In one alternative embodiment, the base sidewall is adapted to contact the inner wall of the guide sleeve.

[0015] Beneficial effects: The base sidewall and the guide sleeve inner wall are designed to fit tightly together, which can effectively prevent the base from shaking or shifting, thereby ensuring the stability of the entire valve structure.

[0016] In one optional embodiment, the valve body is adapted to have a stepped surface on the wall surface that abuts against the valve cover, and the outer wall of one end of the guide sleeve is provided with an outwardly extending annular boss, the annular boss being adapted to abut against the stepped surface.

[0017] Beneficial effects: An outwardly extending annular boss is provided on the outer wall of the upper end of the guide sleeve. The outer diameter of this annular boss precisely matches the inner diameter of the valve body stepped surface. The surface of the annular boss is finely polished to ensure a tight seal when in contact with the valve body stepped surface. This design allows the annular boss to accurately embed into the valve body stepped surface when the guide sleeve is installed into the valve body, providing reliable axial positioning for the guide sleeve and preventing axial movement of the guide sleeve within the valve body.

[0018] In one optional embodiment, the guide sleeve has a cylindrical cavity inside, and the valve disc is slidably disposed within the cylindrical cavity.

[0019] Beneficial effects: During valve operation, the valve disc moves steadily in a linear motion within the cylindrical cavity of the guide sleeve. When the medium flows forward into the valve body, the pressure of the medium acts on the bottom of the valve disc, pushing it to overcome the elastic force of the elastic element and slide upward along the cylindrical cavity. Due to the precise guiding effect of the cylindrical cavity on the valve disc, it maintains a stable posture during its ascent, without swaying or deviating, ensuring smooth valve opening and unobstructed medium flow. When the medium stops flowing forward or shows a reverse flow tendency, the elastic force of the elastic element forces the valve disc to slide downward along the cylindrical cavity, quickly sealing the flow channel within the valve body and preventing reverse medium flow. Throughout the entire movement of the valve disc, the cylindrical cavity provides a stable trajectory, ensuring the valve's response speed and operational reliability.

[0020] In one alternative embodiment, the outer wall of the guide sleeve is in contact with the wall of the columnar cavity.

[0021] In one alternative embodiment, one end of the valve disc has an open cavity, and the elastic element is adapted to be inserted into the cavity.

[0022] Beneficial effects: When the medium flows forward into the valve body, the medium pressure pushes the valve disc upward. The valve disc overcomes the elastic force of the elastic element, causing the elastic element to be gradually compressed within the cavity. Due to the precise fit design between the elastic element and the valve disc cavity, the elastic element maintains a stable axial posture during compression, avoiding tilting or twisting, and ensuring that the elastic force is evenly applied to the valve disc. When the medium stops flowing forward or shows a backflow tendency, the elastic element, under the action of restoring force, pushes the valve disc downward, closing the flow channel within the valve body. During this process, the stable expansion and contraction of the elastic element within the valve disc cavity ensures that the valve disc can quickly and accurately return to its original position, effectively preventing medium backflow.

[0023] In one alternative embodiment, the other end of the valve disc is provided with an abutment portion, which is adapted to block the internal flow channel of the valve body; the abutment portion protrudes from the outer wall surface of the valve disc.

[0024] In one alternative embodiment, the abutment portion is provided with a ramp surface, which is adapted to abut against the inlet of the valve body's internal flow channel.

[0025] In one alternative embodiment, the adjustable pressure lift check valve further includes a sealing gasket disposed between the valve body and the valve cover connection surface.

[0026] Beneficial effects: When the valve is in operation, the pressure generated by the medium within the valve body acts on the sealing gasket. Due to its excellent elasticity and pressure resistance, the sealing gasket adaptively adjusts to changes in medium pressure, maintaining a tight fit with the valve body and bonnet connection surfaces. During frequent valve opening and closing, the sealing gasket effectively buffers the impact forces caused by pressure fluctuations and mechanical vibrations, ensuring stable sealing performance. The presence of the sealing gasket significantly enhances the sealing performance of the valve body and bonnet connection surfaces, effectively preventing medium leakage. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a structural diagram of an adjustable lifting check valve according to an embodiment of the present invention.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Valve body; 2. Valve cover; 3. Guide sleeve; 4. Elastic element; 5. Base; 6. Pin; 7. Sealing gasket; 8. Valve disc. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0032] Check valves, as key valves used to prevent backflow of media, are widely used in many industrial fields such as petroleum, chemical, power, and water supply and drainage, as well as in pipeline systems in daily life. Their working principle is based on the flow pressure of the media itself to open the valve, allowing forward flow. When the media shows a tendency to flow backward, the valve automatically closes to prevent reverse flow, thereby ensuring the safe and stable operation of the system.

[0033] Among the many types of check valves, lift check valves are commonly used due to their relatively simple structure and good sealing performance. A typical lift check valve mainly consists of a valve body, valve disc, valve cover, and spring. The spring plays a crucial role in the valve's operation, providing the closing force to the valve disc and ensuring that the valve disc can close quickly and tightly when the medium stops flowing forward or backflow occurs, preventing backflow.

[0034] However, a significant drawback of existing conventional lift check valves is that their spring force is not adjustable. In actual industrial production and various application scenarios, different operating conditions require different valve opening pressures. For example, in petrochemical plants, the required valve opening pressure may need to be adjusted accordingly as the process flow changes and the type and flow rate of the medium in the pipeline changes. Currently, when adjusting the valve opening pressure, it is often only possible to replace the spring with one of different spring forces. This method is not only cumbersome, requiring professional personnel for disassembly and installation, consuming a lot of time and labor costs, but also, in actual operation, due to the limited reserve of springs of different specifications, it may be impossible to find a perfectly compatible spring in time, leading to prolonged equipment downtime and seriously affecting production efficiency. In addition, frequent spring replacements may also cause wear and tear on other valve components, reducing the overall service life of the valve and increasing equipment maintenance costs.

[0035] In summary, existing conventional lift check valves have limited adaptability to complex and ever-changing operating conditions due to the non-adjustable spring force. There is an urgent need for a lift check valve that can easily and quickly adjust the spring force to meet the diverse needs of practical applications.

[0036] The following is combined Figure 1 The following describes embodiments of the present invention.

[0037] According to an embodiment of this utility model, an adjustable lifting check valve with adjustable opening pressure is provided, including a valve body 1, a valve cover 2, a guide sleeve 3, a valve disc 8, an elastic element 4, a base 5, and a pin 6. The valve cover 2 is connected to the valve body 1. The guide sleeve 3 is disposed inside the valve body 1. In the axial direction of the guide sleeve 3, a plurality of through holes are provided on the side wall of the guide sleeve 3. The valve disc 8 is slidably disposed inside the guide sleeve 3, and the bottom of the valve disc 8 is adapted to block the flow channel inside the valve body 1. The elastic element 4 and the base 5 are disposed inside the guide sleeve 3. One end of the elastic element 4 abuts against the valve disc 8, and the other end of the elastic element 4 abuts against the base 5. The elastic element 4 has an elastic force that forces the valve disc 8 to block the flow channel inside the valve body 1. The base 5 is provided with through holes. The pin 6 is adapted to be inserted into the through holes on the guide sleeve 3 and the base 5.

[0038] The valve cover 2 is tightly connected to the valve body 1. Together, they form the basic outline and enclosed space of the valve, providing stable support and protection for the normal operation of the internal components. The valve body 1, as the main channel for media flow, has internal flow channels. The valve cover 2 seals and secures the internal components, preventing media leakage and facilitating installation and maintenance. The guide sleeve 3 is installed inside the valve body 1. Its main function is to provide precise guidance for the movement of the valve disc 8, ensuring that the valve disc 8 maintains stable linear movement during lifting and lowering, avoiding deviation or swaying, thereby ensuring the valve's sealing performance and reliability. Along the axial direction of the guide sleeve 3, several through holes are evenly distributed on its sidewalls. These through holes play a crucial role in adjusting the valve's opening pressure. The elastic element 4 and the base 5 are both located inside the guide sleeve 3. The elastic element 4 is typically a spring; one end of the elastic element 4 is tightly abutted against the valve disc 8, and the other end is firmly connected to the base 5. In its natural state, the elastic element 4 possesses the elastic force to drive the valve disc 8 to block the flow channel inside the valve body 1, ensuring that the valve can close quickly when the medium stops flowing forward or shows a tendency to flow backward. The base 5 not only provides support for the elastic element 4 but also has through holes on its surface corresponding to the through holes on the side wall of the guide sleeve 3, used to cooperate with the pin 6 to adjust the compression of the elastic element 4. The pin 6, as a key component for regulating the valve opening pressure, has a size and shape that matches the through holes on the guide sleeve 3 and the base 5. By inserting the pin 6 into different combinations of through holes, the position of the base 5 within the guide sleeve 3 can be changed, thereby adjusting the compression of the elastic element 4 and achieving flexible adjustment of the valve opening pressure.

[0039] When the medium flows forward into valve body 1, the pressure of the medium acts on the bottom of valve disc 8, pushing valve disc 8 upward against the elastic force of elastic element 4. As valve disc 8 rises, the flow channel inside valve body 1 gradually opens, allowing the medium to pass smoothly. When the medium stops flowing or shows a backflow tendency, the elastic force of elastic element 4 forces valve disc 8 downward, quickly blocking the flow channel inside valve body 1 and preventing the medium from flowing backward.

[0040] If the valve's opening pressure needs adjustment, the operator simply needs to pull the pin 6 out of its current position according to the actual operating conditions, then select a suitable combination of through holes on the guide sleeve 3 and the base 5, and insert the pin 6 into the new position. By changing the insertion position of the pin 6, the position of the base 5 within the guide sleeve 3 changes accordingly, and the compression of the elastic element 4 also changes accordingly. When the elastic element 4 is compressed more tightly, the elastic force it provides increases, and the valve's opening pressure increases accordingly; conversely, when the compression of the elastic element 4 decreases, its elastic force decreases, and the valve's opening pressure decreases accordingly.

[0041] This adjustable-pressure lift check valve, through its ingenious structural design, allows for convenient adjustment of the valve's opening pressure. Compared to traditional lift check valves, it eliminates the need to replace the spring to meet the valve's opening pressure requirements under different operating conditions, significantly reducing maintenance costs and improving production efficiency. It has broad application prospects in numerous fields such as petroleum, chemical, power, and water supply and drainage.

[0042] In one embodiment, the sidewall of the base 5 is adapted to contact the inner wall of the guide sleeve 3. The close fit between the sidewall of the base 5 and the inner wall of the guide sleeve 3 effectively prevents the base 5 from shaking or shifting, thereby ensuring the stability of the entire valve structure.

[0043] In one embodiment, the valve body 1 has a stepped surface on its wall that abuts against the valve cover 2, and the guide sleeve 3 has an outwardly extending annular boss on the outer wall of one end, which is adapted to abut against the stepped surface. An outwardly extending annular boss is also provided on the outer wall of the upper end of the guide sleeve 3. The outer diameter of this annular boss precisely matches the inner diameter of the stepped surface of the valve body 1. The surface of the annular boss is finely polished to ensure tight contact with the stepped surface of the valve body 1. This design allows the annular boss to precisely embed into the stepped surface of the valve body 1 when the guide sleeve 3 is installed inside the valve body 1, providing reliable axial positioning for the guide sleeve 3 and preventing axial movement of the guide sleeve 3 within the valve body 1.

[0044] This structural design greatly simplifies the operation process during valve assembly. The installer first inserts the guide sleeve 3 into the valve body 1, aligning the annular boss of the guide sleeve 3 with the stepped surface of the valve body 1. Then, the valve cover 2 is placed on top of the valve body 1. While the valve cover 2 is connected to the valve body 1 using bolts or other fastening devices, the pressure of the valve cover 2 is transmitted through the stepped surface to the annular boss of the guide sleeve 3, further securing the guide sleeve 3. This design eliminates the need for additional positioning devices or complex assembly processes, ensuring accurate installation and tight fit between the valve body 1, valve cover 2, and guide sleeve 3, significantly improving valve assembly efficiency and reducing assembly costs.

[0045] In one embodiment, the guide sleeve 3 has a cylindrical cavity inside, and the valve disc 8 is slidably disposed within the cylindrical cavity. During valve operation, the valve disc 8 moves in a stable linear motion within the cylindrical cavity of the guide sleeve 3. When the medium flows forward into the valve body 1, the pressure of the medium acts on the bottom of the valve disc 8, pushing it to overcome the elastic force of the elastic element 4 and slide upward along the cylindrical cavity. Due to the precise guiding effect of the cylindrical cavity on the valve disc 8, the valve disc 8 maintains a stable posture during its ascent, without swaying or deviating, ensuring that the valve can open smoothly and the medium can pass through unimpeded. When the medium stops flowing forward or shows a reverse flow tendency, the elastic force of the elastic element 4 forces the valve disc 8 to slide downward along the cylindrical cavity, quickly sealing the flow channel inside the valve body 1 and preventing the medium from flowing backward. Throughout the entire movement of the valve disc 8, the cylindrical cavity provides it with a stable trajectory, ensuring the valve's response speed and operational reliability.

[0046] In one embodiment, the outer wall of the guide sleeve 3 contacts the wall of the cylindrical cavity. When the valve disc 8 moves up or down within the cylindrical cavity, the guide sleeve 3, through the tight contact between its outer wall and the wall of the cylindrical cavity, achieves more precise guidance of the valve disc 8. Taking the upward movement of the valve disc 8 as an example, during the upward sliding process driven by the medium pressure, the guide sleeve 3, through the tight constraint between its outer wall and the wall of the cylindrical cavity, prevents the guide sleeve 3 from shifting or wobbling, ensuring that the valve disc 8 moves strictly along the predetermined axial direction. Similarly, when the valve disc 8 descends to close the valve, the guide sleeve 3 can also ensure that the valve disc 8 accurately falls back to the sealing position of the flow channel inside the valve body 1, avoiding sealing failure due to deviation. Furthermore, during the frequent opening and closing of the valve, the tight fit between the outer wall of the guide sleeve 3 and the wall of the cylindrical cavity can effectively disperse the lateral force generated by the movement of the valve disc 8, preventing damage to the guide sleeve 3 or the cylindrical cavity due to uneven force distribution.

[0047] In one embodiment, the valve disc 8 has an open cavity at one end, and the elastic element 4 is adapted to be inserted into the cavity. When the medium flows forward into the valve body 1, the medium pressure pushes the valve disc 8 upward, and the valve disc 8 overcomes the elastic force of the elastic element 4, causing the elastic element 4 to be gradually compressed within the cavity. Due to the precise fit design between the elastic element 4 and the cavity of the valve disc 8, the elastic element 4 maintains a stable axial posture during compression, avoiding tilting or twisting, and ensuring that the elastic force is applied evenly to the valve disc 8. When the medium stops flowing forward or shows a backflow tendency, the elastic element 4, under the action of the restoring force, pushes the valve disc 8 downward, closing the flow channel inside the valve body 1. During this process, the stable expansion and contraction of the elastic element 4 within the cavity of the valve disc 8 ensures that the valve disc 8 can quickly and accurately return to its original position, effectively preventing medium backflow.

[0048] In one embodiment, the other end of the valve disc 8 is provided with an abutment portion, which is adapted to block the internal flow channel of the valve body 1; the abutment portion protrudes from the outer wall surface of the valve disc 8. When the medium flows into the valve body 1 in the forward direction, the valve disc 8 moves upward under the action of the medium pressure, and the abutment portion leaves the sealing surface of the internal flow channel of the valve body 1, opening the internal flow channel of the valve body 1 and allowing the medium to pass smoothly. During this process, due to the design of the abutment portion protruding from the outer wall surface of the valve disc 8, it will not retract into the guide sleeve 3.

[0049] In one embodiment, the abutment portion is provided with a ramp surface, which is adapted to abut against the inner flow channel opening of the valve body 1. When the medium stops flowing forward or shows a tendency to flow backward, the valve disc 8 moves downward under the restoring force of the elastic element 4, and the ramp surface of the abutment portion gradually approaches the inner flow channel opening of the valve body 1. As the valve disc 8 continues to descend, the ramp surface gradually contacts the inner flow channel opening of the valve body 1 at an inclined angle, forming a seal at the contact point first. As the contact area continues to increase, the sealing pressure is also evenly distributed, effectively preventing the reverse flow of the medium.

[0050] In one embodiment, the adjustable-pressure lift check valve further includes a sealing gasket 7, which is disposed between the valve body 1 and the valve cover 2. When the valve is in operation, the pressure generated by the medium within the valve body 1 acts on the sealing gasket 7. Due to its excellent elasticity and pressure resistance, the sealing gasket 7 adaptively adjusts with changes in medium pressure, always maintaining a tight fit with the valve body 1 and the valve cover 2. During frequent opening and closing of the valve, the sealing gasket 7 effectively buffers the impact forces caused by pressure fluctuations and mechanical vibrations, ensuring the stability of the sealing performance. The presence of the sealing gasket 7 significantly enhances the sealing performance of the valve body 1 and the valve cover 2, effectively preventing medium leakage. This not only avoids resource waste and environmental pollution caused by medium leakage but also ensures the safe and stable operation of the pipeline system. For applications with extremely high sealing requirements, such as the pharmaceutical and food processing industries, the excellent sealing performance of the sealing gasket 7 is particularly important.

[0051] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A check valve with adjustable opening pressure, characterized in that, include: A valve body (1) and a valve cover (2), wherein the valve cover (2) is connected to the valve body (1); A guide sleeve (3) is disposed inside the valve body (1); a plurality of through holes are provided on the side wall of the guide sleeve (3) along the axial direction; The valve disc (8) is slidably disposed inside the guide sleeve (3), and the bottom of the valve disc (8) is adapted to block the flow channel inside the valve body (1); Elastic element (4) and base (5) are provided inside the guide sleeve (3). One end of the elastic element (4) abuts against the valve disc (8), and the other end of the elastic element (4) abuts against the base (5). The elastic element (4) has an elastic force that forces the valve disc (8) to block the flow channel inside the valve body (1). The base (5) is provided with a through hole. A pin (6) is adapted to be inserted into a through hole in the guide sleeve (3) and the base (5).

2. The adjustable lifting check valve with adjustable opening pressure according to claim 1, characterized in that, The side wall of the base (5) is adapted to contact the inner wall of the guide sleeve (3).

3. The adjustable opening pressure check valve according to claim 1, characterized in that, The valve body (1) is provided with a stepped surface on the wall surface that abuts against the valve cover (2), and the outer wall of one end of the guide sleeve (3) is provided with an outwardly extending annular boss, which is adapted to abut against the stepped surface.

4. The adjustable-pressure check valve according to claim 3, characterized in that, The guide sleeve (3) has a columnar cavity inside, and the valve disc (8) is slidably disposed in the columnar cavity.

5. The adjustable lifting check valve with adjustable opening pressure according to claim 4, characterized in that, The outer wall of the guide sleeve (3) is in contact with the wall of the columnar cavity.

6. The adjustable lifting check valve with adjustable opening pressure according to any one of claims 1-5, characterized in that, The valve disc (8) has an open cavity at one end, and the elastic element (4) is adapted to be inserted into the cavity.

7. The adjustable-pressure check valve according to claim 6, characterized in that, The valve disc (8) has an abutment at the other end, which is adapted to block the flow channel inside the valve body (1); the abutment protrudes from the outer wall of the valve disc (8).

8. The adjustable lifting check valve with adjustable opening pressure according to claim 7, characterized in that, The abutting part is provided with a sloping surface, which is adapted to abut against the flow channel opening inside the valve body (1).

9. The adjustable lifting check valve with adjustable opening pressure according to any one of claims 1-5, characterized in that, It also includes a sealing gasket (7), which is disposed between the connecting surfaces of the valve body (1) and the valve cover (2).

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