Bidirectional pressure limiting valve

Abstract

The utility model relates to the technical field of pressure limiting valves, in particular to a two-way pressure limiting valve. The novel two-way pressure-limiting valve is provided to solve the problem that the pressure of air intake and exhaust of a two-way air intake and exhaust valve in the prior art cannot be automatically adjusted. The air inlet and exhaust functions are ingeniously integrated, automatic air inlet is achieved when the air pressure in the sealed packaging box is smaller than a certain value of the air pressure outside the sealed packaging box, and automatic exhaust is achieved when the air pressure in the sealed packaging box is larger than the certain value of the air pressure outside the sealed packaging box; meanwhile, the opening pressure of the positive pressure difference and the negative pressure difference of the two-way pressure limiting valve under different requirements can be achieved by adjusting the positions of the upper check ring and the lower check ring through threads; in addition, continuous deflation can be achieved through cooperation of the L-shaped clamping groove and the button block, continuous manual pressing deflation is not needed, operation is easy, and economical and practical effects are achieved.

Description

Technical Field

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

[0002] Specially sealed packaging boxes (hereinafter referred to as sealed packaging boxes) need to maintain a constant internal pressure within a certain range. When the external temperature or altitude of the sealed packaging box changes, the relative pressure inside the sealed packaging box will change. When the pressure difference between the inside and outside exceeds a certain value, it is easy to cause damage to the sealed packaging box and the items inside. In order to avoid the occurrence of this problem and ensure that the pressure inside the sealed packaging box is within a constant range, separate exhaust valves and air inlet valves are usually installed. When the internal pressure of the sealed packaging box exceeds or falls below the constant range, the exhaust valve or the air inlet valve is opened for pressure limiting protection. However, installing two valves on the sealed packaging box at the same time is cumbersome to assemble. There are still a small number of sealed packaging boxes in current technology that use two-way air inlet and exhaust valves, but the existing two-way air inlet and exhaust valves on the market have a simple structure and cannot automatically adjust the air intake and exhaust pressure of the two-way air inlet and exhaust valves, making it difficult to meet the pressure range required inside the special sealed packaging box. In addition, when using the two-way exhaust valve to deflate, it takes a long time to manually press the deflation, which is difficult to operate. Summary of the Invention

[0003] In order to solve the problem in the prior art that the intake and exhaust pressures of the two-way intake and exhaust valves cannot be automatically adjusted, the utility model provides a new two-way pressure limiting valve.

[0004] The utility model is realized by adopting the following technical solutions:

[0005] A two-way pressure-limiting valve comprises a cylindrical valve body, a barrel-shaped valve cover with its opening facing downward, a first inclined surface is provided at the bottom end of the inner wall of the valve body, the inclination direction of the first inclined surface is obliquely downward and arranged toward the center of the valve body, a cylindrical first valve core is coaxially slid up and down in the valve body, a second valve core is coaxially slid up and down between the first valve core and the circumference of the valve body, the top end of the second valve core is arranged lower than the top end of the first valve core, the bottom end of the second valve core is arranged higher than the bottom end of the first valve core, and the second valve core comprises a stepped cylindrical body A pressure plate is provided in the middle of the stepped cylinder, and an air inlet and outlet hole is provided on the pressure plate. The uppermost part of the stepped cylinder has the largest diameter and an exhaust hole is provided on its stepped transition surface. The outer wall of the stepped cylinder is provided with a first sealing ring for sealing the gap between the outer wall of the stepped cylinder and the first inclined surface. The bottom end of the inner wall of the stepped cylinder is provided with a second inclined surface. The inclination direction of the second inclined surface is obliquely downward and arranged in a direction away from the center of the valve body. The bottom end of the circumferential wall of the first valve core is provided with a sealing ring for sealing the gap between the second inclined surface and the bottom end of the circumferential wall of the first valve core The second sealing ring of the valve body is fixed with an upper retaining ring at the top end of the valve body, an exhaust spring is provided between the upper retaining ring and the corresponding part of the pressure plate, a lower retaining ring is sleeved on the top end of the circumferential wall of the first valve core, an intake spring is provided at the corresponding part of the lower retaining ring and the pressure plate, the bottom end of the valve cover is outer-roofed and fixed to the top end of the valve body, and a through hole is provided at the connection between the bottom end of the valve cover and the top end of the valve body, a center hole is provided on the top of the valve cover, a center cylinder is fixed integrally at the center hole, a ventilation gap is provided between the outer circumferential wall of the center cylinder and the inner ring of the upper retaining ring, and the center A ventilation space is formed between the outer circumferential wall of the cylinder, the top surface of the valve body, the top surface of the upper retaining ring and the inner wall of the valve cover. The bottom end of the inner wall of the center cylinder is integrally extended inward to be fixed with a convex ring. A push rod is provided in the convex ring to slide up and down. A downward pressure distance is provided between the bottom of the push rod and the top of the second valve core. A button block is fixed to the top end of the push rod. The center part of the button block is fixed to the top end of the push rod. Bumps are provided at both ends of the button block. A groove matching the bumps is provided on the inner wall of the center cylinder. An air release spring is also provided between the convex ring and the button block and is sleeved on the outside of the push rod.

[0006] When in use, the bottom end portion of the two-way pressure-limiting valve is sealed and installed in a sealed packaging box. When the air pressure in the sealed packaging box is greater than a certain value of the air pressure outside the sealed packaging box, the air pressure in the sealed packaging box acts on the second valve core and the first valve core, and the exhaust spring separates the valve body and the second valve core, thereby causing the gas in the sealed packaging box to flow out of the sealed packaging box through the exhaust hole on the second valve core; when the air pressure in the sealed packaging box is less than a certain value of the air pressure outside the sealed packaging box, the air pressure outside the sealed packaging box acts on the first valve core, and the air intake spring separates the first valve core and the second valve core. When the air in the sealed packaging box needs to be deflated, the button block is pressed down, and the push rod is pressed down through the deflation spring, and finally the first valve core is pushed open, so that the first valve core and the second valve core are separated, and the gas in the box passes through the gap between the first valve core and the second valve core, the air inlet and outlet holes of the second valve core, the ventilation gap, the ventilation space, and the through hole in turn to release the gas, and then the button block is released. Under the action of the deflation spring and the air inlet spring, the device returns to its original position.

[0007] Furthermore, threaded connections are provided between the top end of the valve body and the upper retaining ring, as well as between the top end of the first valve core's circumferential wall and the lower retaining ring. These threads allow for adjustment of the position of the upper and lower retaining rings, thereby adjusting the initial preload of the exhaust and intake springs to meet the desired opening pressure requirements for the bidirectional pressure-limiting valve under different positive and negative pressure differentials.

[0008] Furthermore, the two slots on the inner wall of the central tube are both L-shaped slots that are compatible with the two protrusions on the button block and can cooperate with the button block to achieve downward pressure and self-locking. During use, when it is necessary to discharge the gas in the sealed packaging box, the button block is pressed down, the push rod is pressed down, and finally the first valve core is pushed open, so that the first valve core and the second valve core are separated. The gas in the box passes through the gap between the first valve core and the second valve core, the air inlet and outlet holes of the second valve core, the ventilation gap, the ventilation space, and the through hole in sequence and then releases the gas. At the same time, as the button block is pressed down, when the two protrusions contact the bottom of the L-shaped slot, the button block is rotated, so that the button block is self-locked and the gas is continuously released. After the gas in the sealed packaging box is released, the button block is rotated in the opposite direction. Under the action of the exhaust spring and the intake spring, the device returns to its original position.

[0009] Furthermore, the bottom end of the push rod is sleeved with an elastic retaining ring for blocking the bottom end surface of the central tube in the original state of the air release spring to prevent the push rod from falling off from the central hole of the valve cover when the two-way pressure limiting valve is inverted.

[0010] Furthermore, an annular boss is integrally extended from the middle of the outer wall of the valve body, and an assembly seal ring is also provided in the middle of the outer wall of the valve body. The assembly seal ring is located below the annular boss. The portion of the outer wall of the valve body located below the annular boss is provided with external threads. The portion of the valve body provided with external threads is provided with a washer and an adapted mounting nut that slides up and down. When using the bidirectional pressure-limiting valve, the washer and mounting nut are removed, and the bottom end of the bidirectional pressure-limiting valve is first inserted into the sealed packaging box as a whole, so that the outer wall of the sealed packaging box is pressed against the assembly seal ring. The washer and mounting nut are then assembled to the bottom end of the sealed packaging box and the mounting nut is tightened, so that the bidirectional pressure-limiting valve is sealed and installed on the sealed packaging box.

[0011] Furthermore, an annular limiting groove for placing an assembly sealing ring is opened on the bottom surface of the annular boss, which facilitates assembly and improves the sealing effect.

[0012] Furthermore, a square center groove is provided at the top of the first valve core, and the inner ring of the upper retaining ring is hexagonal in shape. The square center groove is designed to allow the first valve core to be secured with a dedicated tool when the lower retaining ring is rotated, preventing the first valve core from rotating with it. The hexagonal inner ring of the upper retaining ring is designed to facilitate the use of a hexagonal wrench to rotate the upper retaining ring.

[0013] Furthermore, the top end of the valve body and the bottom end of the valve cover are connected by threads, which facilitates assembly.

[0014] Furthermore, a circumferential distance of 0.1-0.5 mm is left between the outer wall of the second valve core and the inner wall of the valve body, and a circumferential distance of 0.1-0.5 mm is left between the inner wall of the second valve core and the first valve core.

[0015] Furthermore, the downward pressure distance between the bottom of the push rod and the top of the first valve core is 1-3 mm.

[0016] The beneficial effects produced by the utility model are as follows: the two-way pressure limiting valve described in the utility model cleverly integrates the air intake and exhaust functions, realizing automatic air intake when the air pressure inside the sealed packaging box is lower than a certain value of the air pressure outside the sealed packaging box, and automatic exhaust when the air pressure inside the sealed packaging box is higher than a certain value of the air pressure outside the sealed packaging box; at the same time, the position of the upper retaining ring and the lower retaining ring can be adjusted by the thread, and then the preload force of the exhaust spring and the intake spring can be adjusted, so as to realize the opening pressure of the two-way pressure limiting valve under different requirements of positive pressure difference and negative pressure difference; in addition, the L-shaped card slot is used in combination with the button block to realize continuous deflation, without the need to press the deflation manually, which is simple to operate, economical and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present utility model, and together with the description, are used to explain the principles of the present utility model.

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0019] Figure 1 This is a schematic diagram of the overall structure of the bidirectional pressure-limiting valve described in the present utility model;

[0020] Figure 2 This is a schematic cross-sectional view of the bidirectional pressure-limiting valve of the present invention;

[0021] Figure 3 Schematic diagram of the assembly structure of the valve body and the annular boss;

[0022] Figure 4 The structure of the second valve core is shown in Figure 2. Figure 1 ;

[0023] Figure 5 The structure of the second valve core is shown in Figure 2. Figure 2 ;

[0024] Figure 6 The structure of the second valve core is shown in Figure 2. Figure 3 ;

[0025] Figure 7 Schematic diagram of the valve cover structure Figure 1 ;

[0026] Figure 8 Schematic diagram of the valve cover structure Figure 2 ;

[0027] Figure 9 It is a schematic diagram of the assembly structure of the button block and the ejector rod;

[0028] Figure 10 It is a schematic diagram of the assembly structure of the valve cover, valve body and annular boss.

[0029] In the figure: 1-valve body, 2-valve cover, 3-first inclined surface, 4-square center groove, 5-second inclined surface, 6-first valve core, 7-second valve core, 8-pressure plate, 9-air inlet and outlet holes, 10-exhaust hole, 11-first sealing ring, 12-second sealing ring, 13-upper retaining ring, 14-lower retaining ring, 15-exhaust spring, 16-inlet spring, 17-through hole, 18-center tube, 19-ventilation space, 20-convex ring, 21-top rod, 22-button block, 23-convex block, 24-L-shaped slot, 25-deflation spring, 26-elastic retaining ring, 27-annular boss, 28-assembly sealing ring, 29-washer, 30-mounting nut. DETAILED DESCRIPTION

[0030] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0031] In the description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance. It should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood broadly. For example, they can refer to fixed connections, removable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms based on specific circumstances.

[0032] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0033] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0034] like Figures 1-10The bidirectional pressure limiting valve comprises a valve body 1 in the shape of a cylinder, a valve cover 2 in the shape of a barrel with its opening arranged downward, a first inclined surface 3 arranged on the inner wall bottom end of the valve body 1, the inclination direction of the first inclined surface 3 being inclined downward and arranged toward the direction close to the center of the valve body 1, a first valve core 6 in the shape of a column coaxially sliding up and down in the valve body 1, a second valve core 7 coaxially sliding up and down between the circumference of the valve body 1 and the first valve core 6, the top end of the second valve core 7 being arranged lower than the top end of the first valve core 6, the bottom end of the second valve core 7 being arranged higher than the bottom end of the first valve core 6, the second valve core 7 comprising a stepped cylinder, a pressure bearing plate 8 being arranged on the middle part of the stepped cylinder, an inlet and outlet hole 9 being arranged on the pressure bearing plate 8, the uppermost part of the stepped cylinder having the largest diameter and an exhaust hole 10 being arranged on the stepped transition surface thereof, a first sealing ring 11 being arranged on the outer wall of the stepped cylinder for sealing the gap between the outer wall of the stepped cylinder and the first inclined surface 3, a second inclined surface 5 being arranged on the bottom end of the inner wall of the stepped cylinder, the inclination direction of the second inclined surface 5 being inclined downward and arranged toward the direction away from the center of the valve body 1, a second sealing ring 12 being arranged on the bottom end of the circumferential wall of the first valve core 6 for sealing the gap between the second inclined surface 5 and the bottom end of the circumferential wall of the first valve core 6, an upper stop ring 13 being fixed on the top end in the valve body 1, an exhaust spring 15 being arranged between the corresponding part of the upper stop ring 13 and the pressure bearing plate 8, a lower stop ring 14 being fixed on the top end of the circumferential wall of the first valve core 6, an inlet spring 16 being arranged between the corresponding part of the lower stop ring 14 and the pressure bearing plate 8, the bottom end of the valve cover 2 being fixed on the top end of the valve body 1 and a through hole 17 being arranged at the connection between the bottom end of the valve cover 2 and the top end of the valve body 1, a central hole being arranged on the top of the valve cover 2, a central cylinder 18 being integrally fixed in the central hole, a ventilation gap being arranged between the outer circumferential wall of the central cylinder 18 and the inner ring of the upper stop ring 13, a ventilation space 19 being formed between the outer circumferential wall of the central cylinder 18, the top surface of the valve body 1, the top surface of the upper stop ring 13 and the inner wall of the valve cover 2, a convex ring 20 being integrally extended inwardly on the bottom end of the inner wall of the central cylinder 18, a top rod 21 being slidably arranged in the convex ring 20, a lower pressing distance being arranged between the bottom of the top rod 21 and the top of the second valve core 7, a button block 22 being fixed on the top end of the top rod 21, the center part of the button block 22 being fixed with the top end of the top rod 21, convex blocks 23 being arranged on the two end parts of the button block 22, clamping grooves being arranged on the inner wall of the central cylinder 18 and matched with the convex blocks 23, and a gas release spring 25 being arranged on the top rod 21.

[0035] When in use, the bottom end of the two-way pressure-limiting valve is sealed and installed in a sealed packaging box. When the air pressure in the sealed packaging box is greater than a certain value of the air pressure outside the sealed packaging box, the air pressure in the sealed packaging box acts on the second valve core 7 and the first valve core 6, and the exhaust spring 15 separates the valve body 1 and the second valve core 7, thereby prompting the gas in the sealed packaging box to flow out of the sealed packaging box through the exhaust hole 10 opened on the second valve core 7; when the air pressure in the sealed packaging box is less than a certain value of the air pressure outside the sealed packaging box, the air pressure outside the sealed packaging box acts on the first valve core 6, and the air intake spring 16 separates the first valve core 6 and the second valve core 7, so that The second sealing ring 12 fails, thereby causing the gas outside the sealed packaging box to enter the box through the air inlet and outlet holes 9 opened on the second valve core 7; when the gas in the sealed packaging box needs to be deflated, the button block 22 is pressed down, and the push rod 21 is pressed down through the deflation spring 25, and finally the first valve core 6 is pushed open, so that the first valve core 6 and the second valve core 7 are separated. The gas in the box passes through the gap between the first valve core 6 and the second valve core 7, the air inlet and outlet holes 9 of the second valve core 7, the ventilation gap, the ventilation space 19, and the through hole 17 in turn to release the gas, and then the button block 22 is released. Under the action of the deflation spring 25 and the air inlet spring 16, the device returns to its original position.

[0036] In practice, threaded connections are formed between the top end of the inner portion of the valve body 1 and the upper retaining ring 13, and between the top end of the circumferential wall of the first valve core 6 and the lower retaining ring 14. These threads allow the position of the upper and lower retaining rings 13, 14 to be adjusted, thereby adjusting the initial preload of the exhaust spring 15 and intake spring 16 to meet the opening pressure requirements of the bidirectional pressure-limiting valve under different positive and negative pressure differentials.

[0037] In a specific implementation, the two slots on the inner wall of the central tube 18 are both L-shaped slots 24 that are compatible with the two protrusions 23 on the button block 22 and can cooperate with the button block 22 to achieve downward pressure and self-locking. During use, when it is necessary to discharge the gas in the sealed packaging box, the button block 22 is pressed down, the push rod 21 is pressed down, and finally the first valve core 6 is pushed open, so that the first valve core 6 and the second valve core 7 are separated. The gas in the box passes through the gap between the first valve core 6 and the second valve core 7, the air inlet and outlet holes 9 of the second valve core 7, the ventilation gap, the ventilation space 19, and the through hole 17 in sequence and is released. At the same time, as the button block 22 is pressed down, when the two protrusions 23 contact the bottom of the L-shaped slot 24, the button block 22 is rotated, so that the button block 22 is self-locked and the gas is continuously released. After the gas in the sealed packaging box is released, the button block 22 is rotated in the opposite direction. Under the action of the exhaust spring 25 and the intake spring 16, the device returns to its original position.

[0038] In this specific embodiment, the bottom end of the push rod 21 is sleeved with an elastic retaining ring 26 for blocking the bottom end surface of the central tube 18 in the original state of the air release spring 25 to prevent the push rod 21 from falling off from the center hole of the valve cover 2 when the two-way pressure limiting valve is inverted.

[0039] In this specific embodiment, an annular boss 27 is integrally extended from the middle portion of the outer wall of the valve body 1. An assembly seal ring 28 is also provided in the middle portion of the outer wall of the valve body 1. The assembly seal ring 28 is located below the annular boss 27. The portion of the outer wall of the valve body 1 located below the annular boss 27 is provided with external threads. The portion of the valve body 1 provided with external threads is slidably sleeved with a washer 29 and an adapted mounting nut 30. When using the bidirectional pressure-limiting valve, the washer 29 and mounting nut 30 are removed, and the bottom end of the bidirectional pressure-limiting valve is first inserted into a sealed packaging box as a whole so that the outer wall of the sealed packaging box is pressed against the assembly seal ring 28. The washer 29 and mounting nut 30 are then assembled to the bottom end of the sealed packaging box and the mounting nut 30 is tightened, so that the bidirectional pressure-limiting valve is sealed and mounted on the sealed packaging box.

[0040] In this specific embodiment, an annular limiting groove for accommodating the assembly sealing ring 28 is opened on the bottom surface of the annular boss 27, which facilitates assembly and improves the sealing effect.

[0041] In this embodiment, the top portion of the first valve core 6 is provided with a square center groove 31, and the inner ring of the upper retaining ring 13 is hexagonal in shape. The square center groove 31 allows the first valve core 6 to be secured with a dedicated tool when the lower retaining ring 14 is rotated, thereby preventing the first valve core 6 from rotating with the lower retaining ring 4. The hexagonal inner ring of the upper retaining ring 13 is designed to facilitate the use of a hexagonal wrench to rotate the upper retaining ring 13.

[0042] In this specific embodiment, the top end of the valve body 1 and the bottom end of the valve cover 2 are connected by threads, which facilitates assembly.

[0043] In this embodiment, a circumferential distance of 0.1-0.5 mm is left between the outer wall of the second valve core 7 and the inner wall of the valve body 1, and a circumferential distance of 0.1-0.5 mm is left between the inner wall of the second valve core 7 and the first valve core 6. In this embodiment, the downward pressure distance between the bottom of the push rod 21 and the top of the first valve core 6 is 1-3 mm.

[0044] The above description is only a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments, and they should all be covered by the scope of protection of the claims.

Claims

1. A two-way pressure limiting valve, characterized in that: The invention comprises a cylindrical valve body (1) and a barrel-shaped valve cover (2) with an opening facing downward. The bottom end of the inner wall of the valve body (1) is provided with a first inclined surface (3). The inclined direction of the first inclined surface (3) is obliquely downward and arranged toward the center of the valve body (1). A first cylindrical valve core (6) slides coaxially up and down in the valve body (1). A second valve core (7) slides coaxially up and down between the first valve core (6) and the circumference of the valve body (1). The top end of the second valve core (7) is arranged lower than the top end of the first valve core (6). The bottom end of the second valve core (7) is arranged higher than the bottom end of the first valve core (6). The second valve core (7) comprises a stepped cylindrical body. A pressure plate (8) is provided in the middle of the stepped cylindrical body. The pressure plate (8) is provided with an air inlet and outlet hole (9), the uppermost part of the stepped cylinder has the largest diameter and an exhaust hole (10) is provided on the stepped transition surface, the outer wall of the stepped cylinder is provided with a first sealing ring (11) for sealing the gap between the outer wall of the stepped cylinder and the first inclined surface (3), the bottom end of the inner wall of the stepped cylinder is provided with a second inclined surface (5), the inclination direction of the second inclined surface (5) is obliquely downward and arranged in a direction away from the center of the valve body (1), the bottom end of the circumferential wall of the first valve core (6) is provided with a second sealing ring (12) for sealing the gap between the second inclined surface (5) and the bottom end of the circumferential wall of the first valve core (6), an upper retaining ring (13) is fixed to the top end of the inner side of the valve body (1), and the upper retaining ring (13) is connected to the pressure bearing An exhaust spring (15) is provided between the corresponding parts of the plate (8), a lower retaining ring (14) is sleeved on the top end of the circumferential wall of the first valve core (6), an intake spring (16) is provided on the corresponding parts of the lower retaining ring (14) and the pressure plate (8), the bottom end of the valve cover (2) is fixed to the top end of the valve body (1) and a through hole (17) is provided at the connection between the bottom end of the valve cover (2) and the top end of the valve body (1), a center hole is provided on the top of the valve cover (2), a center tube (18) is fixed integrally at the center hole, a ventilation gap is provided between the outer circumferential wall of the center tube (18) and the inner ring of the upper retaining ring (13), the outer circumferential wall of the center tube (18), the top surface of the valve body (1), and the top of the upper retaining ring (13) are connected. A ventilation space (19) is formed between the surface and the inner wall of the valve cover (2), and a convex ring (20) is fixed to the bottom end of the inner wall of the center tube (18) extending inward as a whole, and a push rod (21) is provided in the convex ring (20) to slide up and down, and a downward pressure spacing is provided between the bottom of the push rod (21) and the top of the second valve core (7), and a button block (22) is fixed to the top end of the push rod (21), and the center of the button block (22) is fixed to the top end of the push rod (21), and convex blocks (23) are provided at both ends of the button block (22). A card groove adapted to the convex block (23) is provided on the inner wall of the center tube (18), and a degassing spring (25) is also provided between the convex ring (20) and the button block (22) and is sleeved on the outside of the push rod (21).

2. A two-way pressure limiting valve according to claim 1, characterized in that: The top end of the inner portion of the valve body (1) and the upper retaining ring (13), as well as the top end of the circumferential wall of the first valve core (6) and the lower retaining ring (14) are both connected via threads.

3. A two-way pressure limiting valve according to claim 2, characterized in that: The two card slots on the inner wall of the central tube (18) are both L-shaped card slots (24) that are adapted to the two protrusions (23) on the button block (22) and can cooperate with the button block (22) to achieve downward pressing and self-locking.

4. A two-way pressure limiting valve according to claim 3, characterized in that: The bottom end of the push rod (21) is sleeved with an elastic retaining ring (26) for blocking the bottom end surface of the center tube (18) when the air release spring (25) is in the original state.

5. A two-way pressure limiting valve according to claim 4, characterized in that: An annular boss (27) is integrally extended from the middle of the outer wall of the valve body (1), and an assembly sealing ring (28) is also provided at the middle of the outer wall of the valve body (1). The assembly sealing ring (28) is located below the annular boss (27). The outer wall of the valve body (1) located below the annular boss (27) is provided with an external thread. The portion of the valve body (1) provided with the external thread is provided with a washer (29) and an installation nut (30) for sliding upward and downward movement.

6. A two-way pressure limiting valve according to claim 5, characterized in that: An annular limiting groove for placing an assembly sealing ring (28) is provided on the bottom surface of the annular boss (27).

7. A two-way pressure limiting valve according to any one of claims 2 to 6, characterized in that: A square center groove (4) is provided at the top end of the second valve core (7), and the inner ring of the upper retaining ring (13) is hexagonal in shape.

8. The two-way pressure limiting valve according to claim 7, characterized in that: The top end of the valve body (1) and the bottom end of the valve cover (2) are connected via threads.

9. The bidirectional pressure-limiting valve according to claim 8, characterized in that: A circumferential distance of 0.1-0.5 mm is left between the outer wall of the second valve core (7) and the inner wall of the valve body (1), and a circumferential distance of 0.1-0.5 mm is left between the inner wall of the second valve core (7) and the first valve core (6).

10. The two-way pressure limiting valve according to claim 9, characterized in that: The downward pressure distance between the bottom of the push rod (21) and the top of the first valve core (6) is 1-3 mm.

Images