CN219472733U

CN219472733U - Low-temperature high-pressure pneumatic control valve

Info

Publication number: CN219472733U
Application number: CN202320365453.9U
Authority: CN
Inventors: 王喜良; 尹会全; 杨浩; 李兴旺; 陈涛; 任志彬; 李欢; 刘耀林; 张思远; 李莹; 范宇; 杨永刚; 张永娜; 李晓瑜
Original assignee: Shaanxi Landspace Technology Co ltd
Current assignee: Landspace Technology Co Ltd
Priority date: 2023-03-02
Filing date: 2023-03-02
Publication date: 2023-08-04
Anticipated expiration: 2033-03-02

Abstract

The utility model discloses a low-temperature high-pressure pneumatic control valve which comprises a shell, a valve seat, a valve cover and a pneumatic control device. The shell is internally provided with a first cavity, a second cavity and a connecting channel which are axially arranged. The pneumatic control device comprises a valve core, an elastic piece and a piston. The valve core is provided with a valve core head, one end of the valve core head is used for being abutted with the end face of the valve seat to seal the medium outlet, and the other end of the valve core head penetrates through the connecting channel and then is connected with the piston positioned in the second cavity, so that the piston is matched with the valve core in the second cavity to perform bidirectional movement to realize opening and closing of the medium outlet. One end of the elastic piece is connected with the end face of one side, far away from the valve seat, of the valve core head, and the other end of the elastic piece is connected with the table top of an annular limiting table arranged on the outer side of the periphery of the connecting channel part formed by the shell, so that elastic force for closing the medium outlet is applied to the valve core. The valve has the advantages of light weight, high response speed and the like.

Description

Low-temperature high-pressure pneumatic control valve

Technical Field

The utility model relates to the field of liquid rockets, in particular to a low-temperature high-pressure pneumatic control valve.

Background

With the rapid development of the aerospace industry, various technologies related to the rocket field also realize rapid progress. The valve is an important component for realizing the start and shutdown of the liquid rocket engine. In particular a low temperature, high pressure pneumatic valve which opens or closes the valve by controlling the high pressure air. As the inlet pressure increases, the force exerted by the medium on the valve element is sufficient to overcome the spring force, and the valve can achieve a self-sustaining open state. When the inlet pressure is reduced, the valve closes under the force of a spring. Such valves are widely used in aerospace engine propellant supply systems.

At present, in the use process of the low-temperature high-pressure air control valve, if the control air pushing the valve to open leaks, the consumption of the control air can be increased or the valve can not be closed, so that the safety of an engine is directly influenced.

The application provides a low temperature high pressure pneumatic control valve, stable in structure, this kind of valve is fast in response speed when working repeatedly, and saves the use of control gas, can guarantee the reliability of engine operation.

Disclosure of Invention

The utility model aims to overcome the defects of the prior art and provides a low-temperature high-pressure pneumatic control valve. The valve has stable structure, high response speed in repeated operation, and can save the use of control gas and ensure the reliability of the engine operation.

In order to achieve the above purpose, the present utility model provides the following technical solutions: the low-temperature high-pressure pneumatic control valve comprises a shell, valve seats and valve covers which are respectively arranged at two ends of the shell, and a pneumatic control device which is arranged between the valve seats and the valve covers, wherein a first cavity, a second cavity and a connecting channel which is used for connecting the first cavity and the second cavity are arranged in the shell along the axial direction, the first cavity is positioned at one side close to the valve seats, and the first cavity comprises a medium inlet which is different from the opening direction of the connecting channel and is used for allowing a low-temperature medium to enter and exit and a medium outlet which is the same as the opening direction of the connecting channel; the second cavity is positioned on one side far away from the valve seat, wherein the second cavity comprises an opening which is different from the opening direction of the connecting channel and is used for controlling gas to enter and exit and a leakage port which is communicated with the opening and is used for discharging a gas medium entering through the opening; guan Qiangkou which is the same as the opening direction of the connecting channel and is communicated with the second cavity is arranged on the valve cover; the pneumatic control device comprises a valve core, an elastic piece and a piston, wherein the valve core is provided with a valve core head, one end of the valve core head is used for being abutted against the end face of the valve seat to seal a medium outlet, and the other end of the valve core head penetrates through the connecting channel and then is connected with the piston positioned in the second cavity, so that the piston is matched with the valve core in the second cavity to perform bidirectional movement to realize the opening and closing of the medium outlet; one end of the elastic piece is connected with the end face of one side, far away from the valve seat, of the valve core head, and the other end of the elastic piece is connected with the table top of an annular limiting table arranged on the outer side of the periphery of the connecting channel part formed by the shell, so that elastic force for closing the medium outlet is applied to the valve core.

Further, one side of the valve seat is embedded into the shell and is clung to the inner surface of the shell, and the valve seat is fixed in the shell through an outlet flange and a locking bolt.

Further, the valve core comprises a valve core head and a connecting rod which are integrally formed, the appearance of the valve core head is approximately a conical head, the top end of the conical head is used for being abutted against the valve seat to close the medium outlet, the bottom end of the valve core head is connected with one end of the connecting rod, and the other end of the connecting rod penetrates through the connecting channel and then is connected with the piston.

Further, the connecting rod contains the different first cylinder of diameter and second cylinder, the diameter of second cylinder is less than first cylinder, just the second cylinder is located and is close to piston one side, follows first cylinder to second cylinder direction first cylinder with second cylinder transition position forms first spacing mesa, wherein, the second cylinder is close to the circumference outside of first cylinder one side is equipped with the retaining ring, just the retaining ring is kept away from piston one side terminal surface with first spacing mesa is hugged closely, is close to piston one side terminal surface with the piston terminal surface is tight.

Further, a concave part matched with the connecting rod is formed in one side, close to the connecting rod, of the piston; the piston comprises a third cylinder and a fourth cylinder with different diameters, and a second limiting table top is formed at the transition part of the third cylinder and the fourth cylinder along the direction from the third cylinder to the fourth cylinder; the circumference outer side of the third cylinder is provided with a sealing piece and a compression ring for fixing the sealing piece on the third cylinder; the end face of one side of the sealing piece is clung to the second limiting table top, the other side of the sealing piece is abutted to one end of the pressing ring, and the other end of the pressing ring is arranged between the outer end face of the piston and the check ring.

Further, a first annular slot and second annular slots which are symmetrically arranged at two sides of the first annular slot along the axial direction of the connecting channel and centered on the first annular slot are further arranged on the inner wall of the shell at the connecting channel.

Further, the shell is further provided with a leakage channel which is communicated with the first annular groove and used for guiding out the control gas in the first annular groove, one end of the leakage channel is communicated with the first annular groove, and the other end of the leakage channel is communicated with the leakage port.

Further, a sealing ring and a supporting ring for supporting the sealing ring are further arranged in the second annular groove, the outer side of the sealing ring is in butt joint with the bottom of the second annular groove, and the inner side of the sealing ring is slidably arranged on the surface of the valve core so that the valve core can slide freely relative to the inner side surface of the sealing ring.

Further, two annular protrusions are formed on the inner side of the shell, and the sealing rings respectively positioned in the two second annular grooves are close to one side of the center of the first annular groove; the support ring is arranged between the annular bulge on the corresponding side and the sealing ring, and the end face, close to one side of the first annular groove, of the sealing ring is tightly attached to the groove wall of the second annular groove by extruding the sealing ring.

Further, the shell is further provided with a blowing opening which is communicated with the first cavity and has a direction different from that of the connecting channel.

Compared with the prior art, the utility model has the beneficial effects that: the low-temperature high-pressure pneumatic control valve consists of a shell, a valve seat, a valve cover and a pneumatic control device. When the valve is opened, control gas enters from the opening cavity, the valve core overcomes the elasticity of the elastic piece and moves to one side of the valve cover, so that the contact end face of the valve core head and the valve seat are separated, a low-temperature medium flows from the medium inlet to the medium outlet, after the pressure of the propellant at the medium inlet reaches a certain value, the control gas can be discharged, and the open state of the valve core is maintained under the action of the low-temperature medium, so that the consumption of the control gas medium is reduced; when the valve is closed, control gas enters from the cavity opening, and the valve core is subjected to pressure towards one side of the valve seat and elasticity of contraction of the elastic piece, so that the valve core head is abutted with the contact end face of the valve seat to seal the medium outlet.

The pneumatic control valve can ensure that the valve core is more stable and smooth during axial movement through the design of the first cavity and the second cavity, and further the valve is conveniently opened/closed.

The valve structure has the advantages that the working process is stable, the opening and closing reliability is high, the response speed is high during repeated working, the use of control gas (gas medium) is saved, and the working reliability of an engine can be ensured.

Drawings

FIG. 1 is a cut-away view of a low temperature, high pressure pneumatic valve with the valve closed;

fig. 2 is a cut-away view of the valve with the low temperature, high pressure pneumatic control valve open.

Reference numerals illustrate:

1 casing 2 valve seat

3 valve cover 4 first cavity

5 second cavity 6 medium inlet

7 medium outlet 8 open cavity mouth

9 leakage port 10 closing cavity port

11 spool 12 elastic member

13 piston 14 retainer ring

15 sealing piece 16 compression ring

17 leakage channel 18 sealing ring

19 support ring 20 blow-off port

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the spirit of the present disclosure will be clearly described in the following drawings and detailed description, and any person skilled in the art, after having appreciated the embodiments of the present disclosure, may make alterations and modifications by the techniques taught by the present disclosure without departing from the spirit and scope of the present disclosure.

The exemplary embodiments of the present utility model and the descriptions thereof are intended to illustrate the present utility model, but not to limit the present utility model. In addition, the same or similar reference numerals are used for the same or similar parts in the drawings and the embodiments.

The terms "first," "second," …, and the like, as used herein, do not denote a particular order or sequence, nor are they intended to limit the utility model, but rather are merely used to distinguish one element or operation from another in the same technical term.

With respect to directional terms used herein, for example: upper, lower, left, right, front or rear, etc., are merely references to the directions of the drawings. Thus, directional terminology is used for purposes of illustration and is not intended to be limiting.

As used herein, the terms "comprising," "including," "having," "containing," and the like are intended to be inclusive and mean an inclusion, but not limited to.

As used herein, "and/or" includes any or all combinations of such things.

The terms "about," "approximately" and the like as used herein are used to modify any quantitative or positional deviation that could vary slightly without such slight variation or positional deviation altering its nature. In general, the range of slight variations or errors modified by such terms may be 20% in some embodiments, 10% in some embodiments, 5% in some embodiments, or other values. It should be understood by those skilled in the art that the above mentioned values can be adjusted according to the actual requirements, and are not limited thereto.

Certain terms used to describe the application will be discussed below, or elsewhere in this specification, to provide additional guidance to those skilled in the art in connection with the description of the application.

Referring to fig. 1 and 2, an embodiment of the present utility model provides a low-temperature high-pressure pneumatic control valve, which comprises a housing 1, a valve seat 2 and a valve cover 3 respectively disposed at two ends of the housing 1, and a pneumatic control device disposed between the valve seat 2 and the valve cover 3. The housing 1 has a first cavity 4, a second cavity 5, and a connecting passage for connecting the first cavity 4 and the second cavity 5, which are arranged in the axial direction. The first chamber 4 is located on the side close to the valve seat 2, wherein the first chamber 4 comprises a medium inlet 6 for ingress and egress of a cryogenic medium in a direction different from the direction of the opening of the connecting channel and a medium outlet 7 in the same direction as the opening of the connecting channel.

The second chamber 5 is located at a side remote from the valve seat 2, wherein the second chamber 5 comprises an opening 8 having a different direction from the opening of the connecting channel for controlling the ingress and egress of gas and a leakage port 9 for communicating with the opening 8 and for discharging gaseous medium entering through the opening 8. The valve cover 3 is provided with a cavity closing opening 10 which is the same as the opening direction of the connecting channel and is communicated with the second cavity 5. The pneumatic control device comprises a valve core 11, an elastic piece 12 and a piston 13, wherein the valve core 11 is provided with a valve core head, one end of the valve core head is used for being abutted against the end face of the valve seat 2 to seal the medium outlet 7, and the other end of the valve core head penetrates through the connecting channel and then is connected with the piston 13 positioned in the second cavity 5, so that the piston 13 is matched with the valve core 11 to perform bidirectional movement in the second cavity 5 to realize the opening and closing of the medium outlet. One end of the elastic member 12 is connected to an end surface of the valve core head on the side away from the valve seat 2, and the other end is connected to a land surface of an annular stopper provided on the outer side of the housing 1 in the circumferential direction forming a connection passage portion, so as to apply an elastic force to the valve core 11 to close the medium outlet 7.

Specifically, the low-temperature high-pressure pneumatic control valve consists of a shell 1, a valve seat 2, a valve cover 3 and a pneumatic control device. When the valve is opened, control gas enters from the opening 8, and the valve core 11 overcomes the elastic force of the elastic piece 12 and moves to one side of the valve cover 3, so that the valve core head is initially separated from the contact end surface of the valve seat 2. The medium enters from the medium inlet, so that the contact end surfaces of the valve core head and the valve seat 2 are completely separated, and the valve is ensured to be in an open state. After the valve is opened, the valve can be kept self-opened by the pressure of the medium, so that the control gas can be discharged, and the working time of the control pipeline under pressure is reduced. When the valve is closed, control gas enters from the closing cavity port 10, and the valve core is subjected to pressure towards one side of the valve seat 2 and elasticity of contraction of the elastic piece 12, so that the valve core head is abutted with the contact end surface of the valve seat 2 to close the medium outlet. The pneumatic control valve of this application guarantees through the design of first cavity 4 and second cavity 5 that case 12 is steady smooth and easy more when axial displacement, and then conveniently realizes opening/closure of valve. The whole valve structure works stably, the response speed is high when the valve is repeatedly closed, the use of control gas (gas medium) is saved, and the working reliability of the engine can be ensured.

The low-temperature high-pressure pneumatic control valve is also suitable for being used as a medium by using liquid propellant, namely when the valve is opened, control gas enters from the opening, the valve core overcomes the elasticity of the elastic piece and moves to one side of the valve cover, so that the contact end face of the valve core head and the valve seat is initially separated, the liquid propellant enters from the medium inlet, and the contact end face of the valve core head and the valve seat 2 is completely separated, so that the valve is ensured to be in an opened state.

In order to fix the valve seat 2 firmly, the valve seat 2 is prevented from being shaken, for example, the valve seat 2 is fitted into the housing 1 and is closely attached to the inner surface of the housing 1, and is fixed in the housing 1 by an outlet flange (not shown in fig. 1) and a lock bolt.

It should be noted that, the valve core 11 includes the valve core head and the connecting rod, in order to make the valve core head be connected with the valve seat more closely, and sealed more rigorous, for example, the appearance of valve core head is roughly conical head, and the top of conical head is used for valve seat 2 butt in order to close medium export 7, and the bottom is connected with the one end of connecting rod, and the other end of connecting rod is connected with piston 13 after penetrating through the connecting channel. In addition, the valve seat 2 is matched with the conical head, so that the contact area between the valve core head and the valve seat 2 is increased, the sealing is more strict, the flow resistance can be effectively reduced due to the design of the conical head, and the low-temperature medium in the valve can flow rapidly. In addition, the connecting channel also plays a guiding role, so that the connecting rod can be prevented from laterally moving (inclining towards the direction deviating from the axial direction), and the connecting rod is connected with the piston 13 more stably. In order to make the connection between the valve core head and the connecting rod tight, the fixing is more firm, for example, the valve core head and the connecting rod are designed in an integrated mode.

In addition, the connecting rod comprises a first cylinder and a second cylinder with different diameters, the diameter of the second cylinder is smaller than that of the first cylinder, and the second cylinder is positioned at one side close to the piston 13. In order to avoid damage caused by direct contact between the piston 13 and the circumferential outer end surface of the connecting channel, which is close to one side of the piston 13, for example, a first limit table surface is formed at a transition part between the first cylinder and the second cylinder along the direction from the first cylinder to the second cylinder, wherein a retainer ring 14 is arranged on the circumferential outer side of one side of the second cylinder, which is close to the first cylinder, and the end surface of one side, which is far from the piston 13, of the retainer ring 14 is tightly attached to the first limit table surface, and the end surface of one side, which is close to the piston 13, is tightly attached to the end surface of the piston 13. The retainer ring 14 can also play a limiting role, and can limit the piston 13 to move to the side of the first cylinder, so that the piston 13 can be ensured to perform work efficiently.

Further, in order to make the connection of the connecting rod with the piston 13 tight, for example, a concave portion matching the connecting rod is provided on the side of the piston 13 close to the connecting rod. In addition, when practical application, the circumference external surface at the position of connecting rod and concave part coincidence still is equipped with the external screw thread, is equipped with the internal screw thread that matches with the external screw thread in the concave part down, and both internal and external screw threads are connected together for both are connected more firmly, still convenient equipment, dismantlement simultaneously. In order to avoid leakage of gaseous medium from between the circumferential outer surface of the piston 13 and the inner wall of the housing in contact with the piston 13, the piston 13 comprises a third cylinder and a fourth cylinder of different diameters. And forming a second limit table top at the transition part of the third cylinder and the fourth cylinder along the direction from the third cylinder to the fourth cylinder. Wherein the third cylinder is provided with a sealing member 15 on the circumferential outer side and a pressure ring 16 for fixing the sealing member 15 to the third cylinder. The end face of one side of the sealing piece 15 is tightly attached to the second limiting table surface, the other side of the sealing piece is abutted to one end of the pressing ring 16, and the other end of the pressing ring 16 is arranged between the outer end face of the piston and the check ring.

In one embodiment, the pressure ring 16 includes an extension portion having a through hole therein, the extension portion having a ring structure, and a contraction portion having a cylindrical body with a gradually increasing size from one end to the other end. The inner side of the extension part is connected with the contraction part along the circumferential outer surface of the large end side of the contraction part, and the outer side of the extension part extends to the side far away from the center line of the contraction part. The small end of the contraction part is also provided with an annular bulge (the annular bulge is a ring body with a pore canal) extending to one side of the central line of the expansion part along the inner wall of the contraction part. The annular bulge is close to the surface of the third cylinder, and the end face of one side of the annular bulge, which is far away from the third cylinder, is close to the end face of one side of the check ring, which is far away from the valve core head, so that the annular bulge is extruded between the third cylinder and the check ring. The retainer ring can exert pressure on the compression ring, so that the compression ring 16 can further fix the sealing element 15, and the sealing element 15 is prevented from being separated from the surface of the third cylinder, so that sealing tightness is improved. In order to further fix the clamping ring, the clamping ring is guaranteed to be stable in structure, for example, one end, far away from the fourth cylinder, of the third cylinder is provided with an inclined plane matched with the inner wall of the shrinkage part, the contact area of the third cylinder and the shrinkage part is increased, and deformation of the clamping ring can be effectively prevented.

For facilitating the connection of the valve seat and the housing, for example, the valve seat comprises a large cylinder, a connecting body and a small cylinder which are axially along the connecting channel and sequentially distributed from the valve cover to the valve seat. The connector is used for connecting the large cylinder and the small cylinder. The large cylinder body and the small cylinder body are cylinders with two communicated ends, and the connecting body is of a frustum structure with one end gradually increasing in diameter towards the other end and two communicated ends. One end face of the large cylinder body is abutted against a table top of an annular limiting boss (an annular limiting boss formed along the inner wall of the shell and positioned on the circumferential inner wall of the connecting channel part) formed by a connecting channel part of the shell, which is close to the medium inlet and far away from the valve cover, and the other end of the large cylinder body is connected with the large end face of the connecting body. The small end face of the connector is connected with one end face of the small cylinder, and the other end of the small cylinder is connected with the end face of the flange, which is close to one side of the valve core. The flange is locked to the shell through the locking bolt, so that the valve seat is extruded between the annular limiting boss and the flange, end faces at two ends of the valve seat are clung to end faces, close to the annular limiting boss and the flange, of the flange, the valve seat is fixed inside the shell, and the valve seat is guaranteed to be fixed firmly. In addition, through big barrel, frustum connector and little barrel and the cooperation of corresponding casing, can improve the stability of valve structure to through setting up seal structure between the dog-ear and the casing of big barrel and annular spacing boss, little barrel and connector junction, further improved the compressed form of sealing member, can improve sealed effect, improve the reliability of valve work.

It should be noted that, in order to reduce the gap between the inner wall of the connection channel portion of the housing 1 and the connecting rod, to avoid leakage of the gas medium through the gap between the two portions, for example, the inner wall of the housing 1 located at the connection channel portion is further provided with a first annular slot and second annular slots symmetrically disposed on two sides of the first annular slot along the axial direction of the connection channel. The second annular slot is also internally provided with the sealing ring 18, and the plurality of sealing rings 18 (at least one sealing ring is arranged in the second annular slot) are arranged, so that the sealing is more strict, and the leakage of a low-temperature medium is further reduced. In order to avoid displacement movement of the sealing ring 18, for example, a supporting ring 19 for supporting the sealing ring is further disposed in the second annular groove, the outer side of the sealing ring 18 is abutted against the bottom of the second annular groove, and the inner side is slidably disposed on the surface of the valve core 11 so that the valve core 11 can slide freely relative to the inner side surface of the sealing ring 18. It should be mentioned in particular that, in order to make the sealing ring 18 fixed firmly against displacement, for example, the housing 1 forms two annular projections towards the inside, said sealing rings 18 being located in two second annular grooves, respectively, each being located close to the central side of the first annular groove. The support ring is arranged between the annular bulge on the corresponding side and the sealing ring 18, and the end face of the sealing ring 18, which is close to one side of the first annular slot, is tightly attached to the slot wall of the second annular slot by extruding the sealing ring 18.

In this embodiment, in order to facilitate the discharge of the medium leaking from the gap between the inner wall of the connecting passage portion of the housing 1 and the connecting rod, for example, the housing 1 is further provided with a vent passage 17 communicating with the first annular groove and for guiding out the control gas located in the first annular groove, wherein one end of the vent passage 17 communicates with the first annular groove and the other end communicates with the leakage port 9.

In addition, when the valve is closed, in order to ensure that the low-temperature medium in the first cavity 4 is close to the medium outlet end and is discharged in time, for example, a blowing opening 20 which is communicated with the first cavity 4 and has a direction different from that of the connecting channel is further arranged on the shell 1. After the propellant supply system of the engine is finished, nitrogen with certain pressure is introduced into the blowing-out port, and the propellant at the medium outlet and downstream is timely discharged out of the engine.

In this embodiment, the elastic member may be a metal spring having elasticity, a double-layered bellows, or the like.

In order to meet the requirements of reliable sealing of the low-temperature high-pressure working environment of the liquid oxygen methane propellant, the structure is more stable, for example, a spring energy storage sealing ring structure is adopted for a sealing element and a sealing ring (the spring energy storage sealing ring structure which is specifically selected can be selected according to working conditions). The spring energy storage sealing ring consists of a polymeric material sealing shell and a corrosion-resistant stainless steel metal spring. The sealing element and the sealing ring are arranged in the groove, the spring is pressed to form outward tension, the sealing lip is urged to cling to the sealing groove, and the spring permanently provides elasticity for the sealing lip, so that the sealing in a low pressure range can be met. In addition, the pressure of the system can assist the spring to store energy, and the greater the pressure is, the more fully the sealing lip is attached to the groove, so that high-pressure sealing is formed.

In addition, a metal sealing surface is arranged between the valve core head and the valve seat so as to adapt to the pressure working condition of not more than 100MPa and prevent the sealing ring from losing efficacy under high pressure. The metal seal forms a first seal, the sealing ring is used as a second seal, even in a high-pressure working environment, the pressure of medium leaked from the first seal to the second seal is greatly reduced, and the redundant design effectively protects the seal, so that the working reliability of the valve is increased. The control valve can be applied to the high-pressure environment with the temperature of-196-100 ℃ and the pressure not higher than 100MPa, and the working range and the sealing reliability are improved.

After the valve is opened, when the pressure of the inlet propellant (cryogenic medium) reaches a certain value, the control gas can be discharged, and the opening state of the valve is maintained under the action of the pressure of the propellant. When the inlet propellant pressure drops to a certain value, the valve core closes under the action of spring force.

In order to make the elastic piece fixed more firmly, for example, be equipped with the spring holder between elastic piece and the case, the spring holder can prevent that medium from striking the elastic piece, avoids causing unstability to the elastic piece.

The above embodiments can be combined with each other with corresponding technical effects.

The foregoing is merely illustrative of the embodiments of this utility model and any equivalent and equivalent changes and modifications can be made by those skilled in the art without departing from the spirit and principles of this utility model.

Claims

1. A low-temperature high-pressure pneumatic control valve is characterized by comprising a shell, valve seats and valve covers which are respectively arranged at two ends of the shell, and a pneumatic control device which is arranged between the valve seats and the valve covers,

the inside of the shell is provided with a first cavity, a second cavity and a connecting channel, wherein the first cavity, the second cavity and the connecting channel are axially arranged,

the first cavity is positioned on one side close to the valve seat, wherein the first cavity comprises a medium inlet which is different from the opening direction of the connecting channel and is used for leading in and out a low-temperature medium and a medium outlet which is the same as the opening direction of the connecting channel;

the second cavity is positioned on one side far away from the valve seat, wherein the second cavity comprises an opening which is different from the opening direction of the connecting channel and is used for controlling gas to enter and exit and a leakage port which is communicated with the opening and is used for discharging a gas medium entering through the opening;

guan Qiangkou which is the same as the opening direction of the connecting channel and is communicated with the second cavity is arranged on the valve cover;

the pneumatic control device comprises a valve core, an elastic piece and a piston, wherein the valve core is provided with a valve core head, one end of the valve core head is used for being abutted against the end face of the valve seat to seal a medium outlet, and the other end of the valve core head penetrates through the connecting channel and then is connected with the piston positioned in the second cavity, so that the piston is matched with the valve core in the second cavity to perform bidirectional movement to realize the opening and closing of the medium outlet; one end of the elastic piece is connected with the end face of one side, far away from the valve seat, of the valve core head, and the other end of the elastic piece is connected with the table top of an annular limiting table arranged on the outer side of the periphery of the connecting channel part formed by the shell, so that elastic force for closing the medium outlet is applied to the valve core.

2. The low temperature, high pressure pneumatic valve of claim 1, wherein the valve seat side is embedded in the housing and is in close proximity to the inner surface of the housing and is secured within the housing by an outlet flange and a locking bolt.

3. The low temperature and high pressure pneumatic control valve of claim 1, wherein the valve core comprises the valve core head and a connecting rod which are integrally formed, the valve core head is approximately conical in shape, the top end of the conical head is used for abutting against the valve seat to close the medium outlet, the bottom end of the conical head is connected with one end of the connecting rod, and the other end of the connecting rod penetrates through the connecting channel and then is connected with the piston.

4. The low-temperature high-pressure pneumatic control valve according to claim 3, wherein the connecting rod comprises a first cylinder and a second cylinder with different diameters, the diameter of the second cylinder is smaller than that of the first cylinder, the second cylinder is located close to one side of the piston, a first limit table surface is formed at the transition part between the first cylinder and the second cylinder along the direction from the first cylinder to the second cylinder, a retainer ring is arranged on the outer side of the second cylinder close to one side of the first cylinder, the retainer ring is far away from one side end surface of the piston and is tightly attached to the first limit table surface, and one side end surface close to the piston is tightly attached to the end surface of the piston.

5. The low-temperature high-pressure pneumatic control valve according to claim 4, wherein a concave part matched with the connecting rod is arranged on one side of the piston close to the connecting rod; the piston comprises a third cylinder and a fourth cylinder with different diameters, and a second limiting table top is formed at the transition part of the third cylinder and the fourth cylinder along the direction from the third cylinder to the fourth cylinder; the circumference outer side of the third cylinder is provided with a sealing piece and a compression ring for fixing the sealing piece on the third cylinder; the end face of one side of the sealing piece is clung to the second limiting table top, the other side of the sealing piece is abutted to one end of the pressing ring, and the other end of the pressing ring is arranged between the outer end face of the piston and the check ring.

6. The low-temperature high-pressure air control valve according to claim 1, wherein the inner wall of the housing at the connecting passage portion is further provided with a first annular groove and second annular grooves arranged on both sides of the first annular groove in the axial direction of the connecting passage with the centers of the first annular grooves being symmetrical.

7. The low temperature, high pressure pneumatic control valve of claim 6, wherein said housing is further provided with a bleed passage in communication with said first annular slot for channeling control gas located within said first annular slot, said bleed passage communicating at one end with said first annular slot and at the other end with said leak port.

8. The low temperature and high pressure pneumatic control valve of claim 6, wherein a sealing ring and a supporting ring for supporting the sealing ring are further arranged in the second annular groove, the outer side of the sealing ring is abutted with the groove bottom of the second annular groove, and the inner side of the sealing ring is slidably arranged on the surface of the valve core so that the valve core can slide freely relative to the inner side surface of the sealing ring.

9. The low-temperature high-pressure pneumatic control valve according to claim 8, wherein two annular protrusions are formed on the inner side of the shell, and the sealing rings respectively positioned in the two second annular grooves are close to one side of the center of the first annular groove; the support ring is arranged between the annular bulge on the corresponding side and the sealing ring, and the end face, close to one side of the first annular groove, of the sealing ring is tightly attached to the groove wall of the second annular groove by extruding the sealing ring.

10. The low temperature and high pressure pneumatic control valve according to claim 1, wherein the housing is further provided with a blow-off port which is communicated with the first cavity and has a direction different from that of the connection passage.