Low-temperature safety valve

Abstract

The low-temperature safety valve comprises a valve body, a valve assembly, a spring and an adjusting nut, wherein the valve assembly, the spring and the adjusting nut are arranged in the valve body. The adjusting nut applies downward force to the valve assembly through the spring, so that the valve assembly is in sealed connection with the air inlet of the valve body. The valve assembly comprises a sealing gasket and a valve connected with the sealing gasket, the valve comprises an upper cylinder and a lower cylinder, an annular groove is formed in the upper cylinder and used for containing a guide ring, and an air inlet hole is formed in the lower cylinder; the guide ring is made of nonmetal fluoroplastic, is very small in friction coefficient, has certain elasticity and hardness and also has very good low temperature resistance, the guide ring is limited in the mounting groove to prevent deformation, the seizure phenomenon caused by friction between the valve and the inner wall of the valve body is avoided, and the safety of the safety valve is improved.

Description

Technical Field

[0001] The invention belongs to the field of cryogenic valves, and in particular relates to a new structure of a cryogenic safety valve. Background Art

[0002] With the rapid development of society, new energy sources such as liquefied natural gas (LNG) and other cryogenic liquefied gases have attracted attention and are widely used. As an important component of cryogenic insulated gas cylinders, cryogenic safety valves play a role in overpressure protection of gas cylinders. When the pressure in the gas cylinder is too high, the safety valve works to release the high-pressure gas in the gas cylinder, thereby reducing the pressure inside the gas cylinder and preventing the inner liner of the gas cylinder from being damaged or exploded due to excessive pressure, thus protecting the gas cylinder.

[0003] In addition to artificial pressurization, the reasons for the high pressure in the gas cylinder include poor insulation of the gas cylinder resulting in excessively high daily evaporation rate, and increased pressure in the gas cylinder tank caused by the bumps of the vehicle-mounted gas cylinder when the motor vehicle is driving. When the above pressurization frequency is too fast, the safety valve will frequently trip, causing damage or leakage to the internal structure of the safety valve, reducing the life of the safety valve, changing the set pressure, causing waste of internal medium, and even more serious situations occur, where the valve and the valve body bite each other and the safety valve fails, the internal gas cannot be released, causing the pressure to rise infinitely, causing damage to the bursting disc, or causing the auxiliary safety valve to trip. In order to solve the above problems, designing a safety valve with stable performance, strong safety, long service life, compact structure, and easy processing has become a key research direction in this field.

[0004] At present, the structure of low-temperature safety valves on the market is basically the same. The valve and valve body materials are brass alloy or stainless steel. When the safety valve is opened and closed, that is, when the valve disc jumps and sits back, the high-pressure gas flows at high speed in the flow channel and the inner cavity of the valve, causing the valve disc to move back and forth in the inner cavity of the valve body, accompanied by high-frequency vibration. The valve disc and the inner cavity of the valve body of the low-temperature safety valve on the market are metal-to-metal. Under high-frequency vibration conditions, high-frequency collisions occur between the valve disc and the inner cavity of the valve body, causing the contact part between the valve disc and the valve body to be severely scratched and damaged, so that the valve disc cannot jump normally, and even the valve disc and the valve body bite each other and cannot jump, resulting in failure of the safety valve, resulting in a reduction in the service life of the safety valve, changes in the set pressure, and waste of internal media. When the valve disc and the valve body bite each other and fail, the gas inside the gas cylinder or pipeline cannot be released, causing the pressure to rise infinitely, causing damage to the bursting disc, or causing abnormal conditions such as the auxiliary safety valve jumping. In more serious cases, the gas cylinder or pipeline will explode. Summary of the invention

[0005] In view of the above technical problems, the purpose of the present invention is to provide a low-temperature safety valve with more stable performance, strong safety, long service life, compact structure, easy processing and no sticking.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: A low-temperature safety valve, comprising a valve body and a valve element assembly, a spring, and an adjusting nut disposed inside the valve body; the adjusting nut applies a downward force to the valve element assembly through the spring, so that the valve element assembly is hermetically connected to the air inlet of the valve body;

[0007] The valve element assembly includes a gasket and a valve element connected to the gasket. The valve element includes an upper cylinder and a lower cylinder. The upper cylinder is provided with an annular groove for placing a guide ring, and the lower cylinder is provided with an air inlet hole.

[0008] As a preferred structure of the present invention, the upper part of the valve body is provided with an internal thread matching the adjusting nut; the middle part of the valve body is provided with an external hexagon for installation and locking integrally formed with the valve body; the lower part of the valve body is provided with an external thread matching an external gas cylinder or pipeline.

[0009] As a preferred structure of the present invention, the inside of the valve body further includes a cavity, a valve seat, and an air inlet passage. The valve seat is disposed at the connection of the cavity and the air inlet passage and is an inverted conical space formed by an arc-shaped inclined surface.

[0010] As a preferred structure of the present invention, the connection angle between the bottom edge and the side wall of the cavity is chamfered.

[0011] As a preferred structure of the present invention, the diameter of the upper cylinder of the valve element is slightly smaller than the inner diameter of the cavity; the bottom diameter of the annular groove is slightly smaller than the inner diameter of the guide ring.

[0012] As a preferred structure of the present invention, the upper cylinder of the valve element is internally provided with a first spring limit groove, and the lower cylinder is internally provided with a gasket installation groove for fixing the gasket.

[0013] As a preferred structure of the present invention, the adjusting nut is internally provided with a second spring limit groove, and the top of the adjusting nut is provided with an air outlet, and the shape of the air outlet can be adapted to an external adjusting tool.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] 1. The present invention opens an annular groove on the valve element and installs a guide ring. When the pressure in the gas cylinder acting on the gasket is greater than the force of the spring acting on the valve element assembly, the gasket disengages from the valve seat. When the gas in the gas cylinder rushes to the valve element assembly, the gas will expand the guide ring. After the guide ring is expanded, it contacts the inner wall of the valve body, thus showing the following advantages:

[0016] (1) Reduce the friction between the valve flap and the inner wall of the valve body: The valve flap and the valve body are usually made of copper alloy or stainless steel. If they collide with each other, it will cause permanent damage, thus affecting the normal operation of the valve flap assembly. In the present invention, the guiding ring is made of non-metallic fluoroplastics, which has a very small friction coefficient, certain elasticity and hardness, and very good low-temperature resistance. The guiding ring is restricted in the groove to prevent deformation or detachment, avoiding the jamming phenomenon caused by the friction between the valve flap and the inner wall of the valve body, and improving the safety of the safety valve;

[0017] (2) When the expanded guiding ring contacts the inner wall of the valve body, a seal between the valve flap and the inner wall of the valve body is formed, so that the discharged gas can only be discharged through the air inlet holes provided on the valve flap. The gas coming out of the air inlet holes will press the valve flap assembly in the reverse direction, enabling the gasket to tightly press the valve seat in a very short time, thus achieving rapid sealing and reducing the gas waste in the gas cylinder.

[0018] 2. Chamfer the connecting corner of the bottom edge and the side wall of the cavity, so that the gas in the gas cylinder can be discharged along the chamfer arc when discharged, thereby accelerating the gas discharge speed, making the exhaust smoother, reducing the residence time of the gas in the inner cavity of the valve body, and achieving less friction between the valve flap and the inner cavity of the valve body. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the overall structure of a cryogenic safety valve in this embodiment.

[0020] Figure 2 It is a schematic diagram of the valve body structure of a cryogenic safety valve in this embodiment.

[0021] Figure 3 It is a schematic diagram of the valve flap assembly structure of a cryogenic safety valve in this embodiment Figure 1 .

[0022] Figure 4 It is a schematic diagram of the valve flap assembly structure of a cryogenic safety valve in this embodiment Figure 2 .

[0023] Figure 5 It is a schematic diagram of the adjusting nut structure of a cryogenic safety valve in this embodiment.

[0024] Among them, 1 is the valve body; 2 is the valve flap assembly; 3 is the spring; 4 is the adjusting nut;

[0025] 11 is the internal thread; 12 is the external hexagon; 13 is the external thread; 14 is the cavity; 15 is the valve seat; 16 is the air inlet channel; 17 is the arc-shaped inclined surface;

[0026] 21 is the gasket; 22 is the valve flap; 23 is the guiding ring; 221 is the annular groove; 222 is the air inlet hole; 223 is the first spring limiting groove; 224 is the gasket installation groove;

[0027] 41 is the second spring limit groove; 42 is the air outlet. Specific embodiments

[0028] To describe in detail the technical content, structural features, achieved objectives and effects of the technical solution, the following will be described in detail with reference to specific embodiments and in conjunction with the accompanying drawings.

[0029] As Figure 1 shown, in this embodiment, a schematic diagram of the overall structure of a low-temperature safety valve includes a valve body 1 and a valve element assembly 2, a spring 3, and an adjusting nut 4 disposed inside the valve body 1; the adjusting nut 4 applies a downward force to the valve element assembly 2 through the spring 3, so that the valve element assembly 2 is hermetically connected to the air inlet of the valve body 1;

[0030] The valve element assembly 2 includes a sealing gasket 21, a valve element 22 connected to the sealing gasket 21, and a guide ring 23. The valve element 22 includes an upper cylinder and a lower cylinder. The upper cylinder is provided with an annular groove 221 for placing the guide ring 23, and the lower cylinder is provided with an air inlet hole 222.

[0031] As a preferred structure of this embodiment, the upper part of the valve body 1 is provided with an internal thread 11 that mates with the adjusting nut 4; the middle part of the valve body 1 is provided with an external hexagon 12 for installation and locking that is integrally formed with the valve body 1; the lower part of the valve body 1 is provided with an external thread 13 that matches an external gas cylinder.

[0032] As a preferred structure of this embodiment, the inside of the valve body 1 further includes a cavity 14, a valve seat 15, and an air inlet passage 16. The valve seat 15 is disposed at the connection of the cavity 14 and the air inlet passage 16 and is an inverted conical space formed by an arc-shaped inclined surface 17.

[0033] As a preferred structure of this embodiment, the connection angle between the bottom edge and the side wall of the cavity 14 is chamfered.

[0034] As a preferred structure of this embodiment, in order to avoid contact friction between the valve element 22 and the inner wall of the cavity 14, the diameter of the upper cylinder of the valve element 22 is slightly smaller than the inner diameter of the cavity 14; in order to enable gas to smoothly enter the annular groove 221, the outer diameter of the annular groove 221 is slightly smaller than the inner diameter of the guide ring 23, so that the gas expands the guide ring, and the expanded guide ring contacts the inner wall of the valve body, better reducing the friction between the valve element and the inner wall of the valve body.

[0035] As a preferred structure of this embodiment, the upper cylinder of the valve element 22 is internally provided with a first spring limit groove 223, and the lower cylinder is internally provided with a sealing gasket installation groove 224 for fixing the sealing gasket 21.

[0036] As a preferred structure of this embodiment, a second spring limiting groove 41 is provided inside the adjusting nut 4, and an air outlet 42 is provided at the top of the adjusting nut 4. The shape of the air outlet 42 can be adapted to external adjusting tools, including shapes such as pentagon, hexagon, ellipse, and grooves on the outer side of the top.

[0037] As a preferred structure of this embodiment, the guiding ring 23 is made of a low-temperature-resistant non-metallic material, including high-molecular polymer materials such as polytetrafluoroethylene, reinforced polytetrafluoroethylene, PFA, PCTFE, UPE, and PEEK.

[0038] As a preferred structure of this embodiment, the number of the air inlet holes 222 can be set to 2 - 6, and in this embodiment, it is 4.

[0039] For the cryogenic insulated gas cylinder or pipeline installed with the cryogenic safety valve disclosed in this embodiment, the risk that the safety valve jams and fails to trip when the internal pressure of the gas cylinder or pipeline exceeds the pressure is greatly eliminated. It has better sealing performance, reduces the occurrence of air leakage of the safety valve, has a stable discharge pressure, and enables the gas cylinder to operate safely and stably for a long time.

[0040] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A cryogenic safety valve, characterized in that: The invention comprises a valve body (1), and a valve assembly (2), a spring (3), and an adjusting nut (4) arranged inside the valve body (1); the adjusting nut (4) applies a downward force to the valve assembly (2) through the spring (3), so that the valve assembly (2) maintains a sealed connection with the air inlet of the valve body (1); The valve assembly (2) comprises a sealing gasket (21), a valve (22) connected to the sealing gasket (21), and a guide ring (23); the valve (22) comprises an upper cylinder and a lower cylinder; the upper cylinder is provided with an annular groove (221) for accommodating the guide ring (23); and the lower cylinder is provided with an air inlet hole (222).

2. A cryogenic safety valve according to claim 1, characterized in that: The upper portion of the valve body (1) is provided with an internal thread (11) matching the adjusting nut (4); the middle portion of the valve body (1) is provided with an external hexagonal screw (12) for mounting and locking, which is integrally formed with the valve body (1); and the lower portion of the valve body (1) is provided with an external thread (13) matching an external gas cylinder or a pipeline.

3. A cryogenic safety valve according to claim 1, characterized in that: The valve body (1) further comprises a cavity (14), a valve seat (15) and an air inlet passage (16); the valve seat (15) is arranged at the connection between the cavity (14) and the air inlet passage (16) and is an inverted cone-shaped space formed by an arc-shaped inclined surface (17).

4. A cryogenic safety valve according to claim 3, characterized in that: The connection angle between the bottom edge and the side wall of the cavity (14) is chamfered.

5. A cryogenic safety valve according to claim 3, characterized in that: The diameter of the upper cylinder of the valve (22) is slightly smaller than the inner diameter of the cavity (14); and the bottom diameter of the annular groove (221) is slightly smaller than the inner diameter of the guide ring (23).

6. A cryogenic safety valve according to claim 1, characterized in that: A first spring limiting groove (223) is provided inside the upper cylinder of the valve (22), and a sealing gasket installation groove (224) is provided inside the lower cylinder for fixing the sealing gasket (21).

7. A cryogenic safety valve according to claim 1, characterized in that: A second spring limiting groove (41) is provided inside the adjusting nut (4), and an air outlet (42) is provided on the top of the adjusting nut (4), wherein the shape of the air outlet (42) matches an external adjusting tool.

8. A cryogenic safety valve according to claim 1 or 5, characterized in that: The guide ring (23) is made of non-metallic materials that can withstand low temperatures, including polytetrafluoroethylene, reinforced tetrafluoroethylene, PFA, PCTFE, UPE and PEEK high molecular polymer materials.

9. A cryogenic safety valve according to claim 1, characterized in that: The number of the air inlet holes (222) is N, and 2≤N≤6.

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