CN114754162A

CN114754162A - Low-temperature ball valve

Info

Publication number: CN114754162A
Application number: CN202210394421.1A
Authority: CN
Inventors: 林峰; 林童; 舒婷洁; 谢尚铪; 陆元成; 王平红
Original assignee: Zhejiang Beier Control Valve Co ltd
Current assignee: Zhejiang Beier Control Valve Co ltd
Priority date: 2022-04-15
Filing date: 2022-04-15
Publication date: 2022-07-15
Anticipated expiration: 2042-04-15
Also published as: CN114754162B

Abstract

The invention relates to the technical field of valves, in particular to a low-temperature ball valve which comprises a valve body, a ball valve core, a valve rod, a pressure relief unit, a sealing assembly, an upper valve cover and a lower valve cover; one end of the valve body is an inlet pipe, the other end of the valve body is an outlet pipe, the ball-shaped valve core is arranged in the middle of the valve body and used for isolating or communicating the inlet pipe and the outlet pipe, and the valve body penetrates into the valve body and is connected with the ball-shaped valve core; the pressure relief unit is arranged in the valve body; the sealing component is arranged in the valve body and communicated with the pressure relief unit to receive partial pressure relief medium; the upper valve cover is hermetically fixed at the top of the valve body; the lower valve cover is hermetically fixed at the bottom of the valve body and communicated with the pressure relief unit or the spherical valve core; the ball valve is provided with the pressure relief unit, the cavity is arranged in the lower valve cover, the cavity can be communicated with the inlet pipe and the outlet pipe, and the discharged part of the medium is decompressed in the cavity or discharged through the cavity under the medium expansion and high pressure state.

Description

Low-temperature ball valve

Technical Field

The invention relates to the technical field of valves, in particular to a low-temperature ball valve.

Background

With the development of chemical engineering projects in recent years, more and more technological processes need to be carried out at low temperature, such as petrochemical industry, coal chemical industry, refrigeration and other industries. The low-temperature conveying media are usually flammable and explosive media such as liquefied petroleum gas, liquefied natural gas and the like, and the volumes of the media are rapidly expanded or gasified when the temperature of the media is increased, so that leakage and explosion are easily caused.

In the technical standard of the low-temperature valve, the requirement of installing a pressure relief hole on the valve is not provided. However, because the gasified medium has the risk of leakage and explosion, the existing valve body is designed to be decompressed, but the stored medium is directly discharged through a decompression hole to pollute the environment, and the sealing performance of the valve core is affected when the medium expands, so that the medium leakage and expansion are reduced by the decompression purpose, the medium which is dredged by decompression is reused on the sealing of the valve core to improve the sealing performance of the valve body, and the low-temperature ball valve is provided.

Disclosure of Invention

The invention aims to provide a low-temperature ball valve for solving the problems of explosion and leakage caused by expansion of a medium.

In order to achieve the purpose, the invention adopts the following technical scheme:

a low-temperature ball valve comprises a valve body, a ball valve core, a valve rod, a pressure relief unit, a sealing assembly, an upper valve cover and a lower valve cover;

the ball-type valve core is arranged in the middle of the valve body and used for isolating or communicating the inlet pipe and the outlet pipe, and the valve body penetrates into the valve body and is connected with the ball-type valve core; the pressure relief unit is arranged in the valve body and used for reducing pressure or relieving pressure of a storage medium; the sealing assembly is arranged in the valve body and is contacted with the ball valve core, and the sealing assembly is communicated with the pressure relief unit and receives a part of pressure relief medium; the upper valve cover is fixed at the top of the valve body in a sealing way and is penetrated by the valve rod; the lower valve cover is fixed at the bottom of the valve body in a sealing mode, communicated with the pressure relief unit or the ball-shaped valve core and used for medium dilution during pressure reduction or exhaust during sealing.

Furthermore, a first limiting groove and a second limiting groove are formed in the ball cavity of the valve body close to the inlet pipe and the outlet pipe respectively, the first limiting groove is communicated with the interior of the inlet pipe, and the second limiting groove is communicated with the interior of the outlet pipe.

Furthermore, the inside pressure release groove that communicates with the outside has all been seted up to the upper and lower side of valve body, first ring pipeline has been seted up to the inlet tube inside, the inside second ring pipeline of having seted up of outlet pipe, first ring pipeline and second ring pipeline communicate with the pressure release groove of neighbour respectively.

Further, the pressure relief unit comprises a pressure valve and an electromagnetic valve; the pressure valve is arranged on the inlet pipe and is communicated with the first annular pipeline, and the electromagnetic valve is arranged on the outlet pipe and is communicated with the second annular pipeline.

Further, the pressure valve comprises a sealing rod and a spring; the sealing rod penetrates through the first annular pipeline and penetrates through the pipe wall of the inlet pipe, and the spring is fixed on the outer side of the sealing rod and fixed with the outer wall of the inlet pipe.

Further, the sealing assembly comprises a sealing strip and a sealing air bag, the sealing strip is installed inside the first limiting groove, the sealing air bag is communicated with the inside of the second limiting groove and the pressure relief groove, and fluffy materials for expanding the sealing air bag are filled inside the sealing air bag.

Furthermore, a cavity is formed in the lower valve cover, pressure sensors are mounted at the upper end and the lower end of the cavity, a piston plate is movably arranged in the cavity, the side edge of the cavity is provided with an opening and is communicated with a pressure relief groove, and the bottom of the lower valve cover is communicated with an inflation pipe.

Furthermore, still include the throat subassembly, the throat subassembly is used for controlling the medium flow rate when the ball valve is opened to including sleeve pipe, throat board, the sleeve pipe cover is located the import outside of tubes, the inside ring channel of having seted up of sleeve pipe, the throat board slope sets up one end and penetrates inside the import pipe through with slider and ring channel inner wall swing joint, the other end.

Furthermore, a first limiting hole is arranged at the bottom end of the spherical valve core, and a one-way valve is arranged in the limiting hole.

Furthermore, a second limiting hole communicated with the first limiting hole is formed in the lower valve cover, and the end of the second limiting hole is connected with an air inlet pipe.

Compared with the prior art, the invention provides paper cup detection equipment which has the following beneficial effects:

1. the ball valve is provided with the pressure relief unit, the cavity is arranged in the lower valve cover, the cavity can be communicated with the inlet pipe and the outlet pipe, and the discharged part of the medium is decompressed in the cavity under the expansion and high-pressure state of the medium, so that the medium is prevented from being directly discharged to the outside to cause pollution and can be discharged from the outlet pipe.

2. According to the invention, the sealing strip and the sealing air bag are arranged in the valve body to carry out double-layer sealing on the spherical valve core so as to provide sealing property under the closing of the ball valve, and the sealing air bag is filled with fluffy matters to realize expansion and contact with the spherical valve core, and a pressure relief medium is introduced to increase the friction force on the spherical valve core, so that the sealing effect is enlarged.

3. According to the invention, the pipe throat plate is obliquely inserted into the inlet pipe, the sleeve is utilized to control the length of the pipe throat plate extending to the inner part of the inlet pipe, the medium is distributed in the inlet pipe through the pipe throat plate in the opening state of the ball valve, the negative pressure value of the medium passing through the ball valve core is increased, the ball valve core is enabled to suck diluent gas to the inner part of the first limiting hole, the dilution and discharge of the medium are realized, and the explosion of high-concentration medium is avoided.

Drawings

Fig. 1 is an overall cross-sectional structural schematic view in embodiment 1 of the present invention;

fig. 2 is a schematic view of an overall cross-sectional split structure of the rear valve rod, the upper valve cover, the lower valve cover and the like in embodiment 1 of the present invention;

FIG. 3 is a schematic view of a pressure relief unit according to the present invention;

FIG. 4 is an enlarged schematic view of the structure at A in FIG. 2 according to the present invention;

FIG. 5 is a schematic view of the seal assembly of the present invention;

FIG. 6 is a schematic cross-sectional view of the sealed bladder of the present invention;

FIG. 7 is a cross-sectional view of a lower valve cover and a related structure thereof according to embodiment 1 of the present invention;

FIG. 8 is a schematic sectional view showing a valve body according to embodiment 1 of the present invention;

FIG. 9 is an overall sectional view schematically showing the structure in embodiment 2 of the present invention;

FIG. 10 is an overall sectional view schematically illustrating the pipe throat assembly of embodiment 2 of the present invention after being removed;

FIG. 11 is a schematic view of the lower bonnet and throat assembly of example 2 of the present invention;

FIG. 12 is an overall sectional structural view of embodiment 3 of the present invention;

fig. 13 is a schematic view of a cross-sectional lower valve cover structure according to embodiment 3 of the invention.

The reference numbers in the figures illustrate: 100. a valve body; 101. an inlet pipe; 102. an outlet pipe; 103. a first limit groove; 104. a second limit groove; 105. a pressure relief groove; 106. a first annular duct; 107. a second toroidal tube; 200. a ball valve core; 201. a first limit hole; 202. a one-way valve; 300. a valve stem; 400. a pressure relief unit; 401. a pressure valve; 402. an electromagnetic valve; 403. a sealing rod; 404. a spring; 500. a seal assembly; 501. a sealing strip; 502. sealing the air bag; 600. an upper valve cover; 700. a lower valve cover; 701. a cavity; 702. a pressure sensor; 703. a piston plate; 704. an inflation tube; 705. a second limiting hole; 706. an air inlet pipe; 800. a throat assembly; 801. a sleeve; 802. a throat plate; 803. an annular groove.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

The present invention will be further described with reference to the following examples.

Example 1:

a low-temperature ball valve comprises a valve body 100, a ball valve core 200 and a valve rod 300;

one end of the valve body 100 is an inlet pipe 101, and the other end is an outlet pipe 102, the ball-type valve core 200 is installed in the middle of the valve body 100 for isolating or communicating the inlet pipe 101 and the outlet pipe 102, and the valve body 100 penetrates into the valve body 100 and is connected with the ball-type valve core 200;

a pressure release unit 400 installed inside the valve body 100 to reduce pressure or release pressure of the storage medium;

a sealing assembly 500 installed inside the valve body 100 and contacting the ball-type valve core 200, the sealing assembly 500 being communicated with the pressure relief unit 400 and receiving a part of a pressure relief medium;

An upper bonnet 600 hermetically fixed to the top of the valve body 100 and penetrated by the valve stem 300;

and the lower valve cover 700 is hermetically fixed at the bottom of the valve body 100, and the lower valve cover 700 is communicated with the pressure relief unit 400 or the ball-type valve core 200 and is used for diluting a medium during exhaust in sealing.

Some embodiments of the present application are described in detail below with reference to the following drawings:

referring to fig. 1-2, in the embodiment of the present application, the middle of the valve body 100 is a spherical valve cavity and is installed with a spherical valve core 200, two symmetrical side edges of the valve body 100 are communicated with the outside and are fixed with the inlet pipe 101 and the outlet pipe 102, the upper and lower ends of the valve body 100 are open, the upper and lower ends of the valve body 100 are respectively fixed with the upper valve cover 600 and the lower valve cover 700 to seal the spherical valve cavity, the middle of the upper valve cover 600 of one valve rod 300 penetrates into the valve body 100 to be engaged with the spherical valve core 200, the rotation of the spherical valve core 200 is realized by controlling the valve rod 300, and the opening and closing of the ball valve is realized, that is, the inlet pipe 101 is isolated from or communicated with the outlet pipe 102.

In the implementation process, in order to realize the sealing performance of the ball valve when the ball valve is closed, the sealing assembly 500 is designed, but before the sealing assembly is used again, the first limiting groove 103, the second limiting groove 104 and the pressure relief groove 105 are firstly formed in the valve body 100; wherein the first limiting groove 103 and the second limiting groove 104 are respectively opened at positions close to the inlet pipe 101 and the outlet pipe 102. The pressure relief groove 105 is symmetrically installed at the bottom of the valve body 100 for communicating a medium discharged by pressure relief in a sealed state, wherein one end of the pressure relief groove 105 is directly communicated with the outside of the valve body 100, and the medium discharged by pressure relief is directly discharged to the outside or collected for treatment.

Referring to fig. 5-6, the sealing assembly 500 includes a sealing strip 501, a sealing bladder 502, etc.; the sealing strip 501 is installed inside the first limiting groove 103 as a first sealing line, and the sealing strip 501 improves the sealing effect through interference fit with the ball valve element 200.

And the sealing airbag 502 is installed inside the second limiting groove 104 as a second sealing line, and the sealing airbag 502 improves the sealing effect through interference fit with the ball valve core 200. It should be noted that the sealing air bag 502 is hollow, and is naturally expanded by filling some expansion materials, such as sponge, cotton wool, etc., when being installed, and is in interference fit with the ball valve core 200 when being expanded. In addition, the sealing air bag 502 is also communicated with the pressure relief groove 105, and a medium discharged by pressure relief can be introduced to continuously expand so as to enlarge the friction effect.

In some embodiments, the pressure relief groove 105 may be connected to the inside of the air bag 502 and may be vented from the air bag 502 when the flow rate of the pressure relief medium is small. Maintaining the sealed balloon 502 inflated continuously.

In some embodiments, under the condition of large flow of the pressure-releasing medium, the air-tight bag 502 is communicated with the pressure-releasing groove 105 through a branch pipe, and a small amount of pressure-releasing body is gathered to complete the continuous expansion of the air-tight bag 502.

Referring to fig. 3 to 4, in the embodiment of the present application, a pressure relief unit 400 of a ball valve is provided on the inlet pipe 101 and the outlet pipe 102. Here, the pressure relief unit 400 includes a pressure valve 401, a solenoid valve 402, and the like; first, a first annular pipe 106 and a second annular pipe 107 are distributed inside the inlet pipe 101 and the outlet pipe 102 near the valve body 100. The last downside of import pipe 101 has all installed pressure valve 401, utilizes the first toroidal tube 106 of pressure valve 401 separation and has communicated with import pipe 101, and under the ball valve closed state, if the atmospheric pressure risees in the import pipe 101 inside, pressure valve 401 pressurized takes place the deformation back, can first toroidal tube 106 and import pipe 101 intercommunication, and inside the pressure release medium flowed into first toroidal tube 106, outwards discharged through pressure release groove 105. Solenoid valves 402 are mounted on both the upper and lower sides of the outlet pipe 102, wherein the solenoid valves 402 carry a control unit for automatically controlling the communication and configuration of the second annular duct 107 with the outlet pipe 102.

Wherein, pressure valve 401 is composed of sealing rod 403, spring 404 and the like, sealing rod 403 passes through first annular pipe 106 from the outside and projects to the inner wall of inlet pipe 101, and is fixed outside sealing rod 403 and with the outer wall of inlet pipe 101 by spring 404, and sealing rod 403 is supported by spring 404 to be flush with the inner wall projecting to inlet pipe 101. After the end of the sealing rod 403 is pressed, it slides outwards and deforms the spring 404.

Please refer to fig. 7, it should be noted that, after one end of the lower pressure relief groove 105 is communicated with the first annular pipe 106 or the second annular pipe 107, the other end includes a first branch groove, a second branch groove, and a third branch groove, the first branch groove is communicated with the air pipe of the sealed air bag 502, the second branch groove is communicated with the outside of the valve body (100), but in the implementation, the third branch groove is communicated with the cavity 701. After one end of the upper pressure relief groove 105 is communicated with the first annular pipeline 106 or the second annular pipeline 107, the other end of the upper pressure relief groove comprises a first branch groove and a second branch groove, the first branch groove is communicated with an air pipe of the sealing air bag 502, and the second branch groove is communicated with the outside of the valve body (100) and is in a sealing state in implementation.

Referring to fig. 2 and 8, in the embodiment of the present application, the lower bonnet 700 is used for storing a pressure relief medium or conducting flow, in addition to sealing the bottom of the valve body 100. Therefore, the lower valve cover 700 is thickened, a cavity 701 is formed in the lower valve cover 700, the middle of the upper end and the lower end of the cavity 701 are provided with grooves, a pressure sensor 702 is mounted in each groove, a piston plate 703 is movably arranged in the cavity 701, the bottom end of the cavity 701 is communicated with an inflation pipe 704 in a staggered mode with the pressure sensor 702 below, and the side edge of the cavity 701 is provided with a hole. After the lower bonnet 700 is fixed to the valve body 100, the cavity 701 communicates with the pressure relief grooves 105 on both sides. Wherein the piston plate 703 stratifies the cavity 701 and separates the charge gas from the exhaust medium.

The pressure relief principle in the foregoing is: after the air pressure inside the inlet pipe 101 is increased, the sealing rod 403 which is moved by pressure makes the first annular pipe 106 communicate with the inlet pipe 101, discharges a medium into the first annular pipe 106, and diffuses outward through the pressure relief groove 105, but does not directly discharge to the outside, but flows into the sealing bladder 502 in a small amount, and the rest exists inside the cavity 701.

Wherein, a certain amount of medium is injected into the cavity 701 through the inflation tube 704, the piston plate 703 is lifted to the highest point and pressed towards the pressure sensor 702 on the upper side, and after a certain pressure intensity is maintained in the cavity 701, the inflation tube 704 is sealed by using a pressure sensing valve. After the pressure relief medium flows into the top of the cavity 701, the piston plate 703 is continuously pressed, and the filled medium is gradually discharged after the air pressure below the piston plate 703 reaches the threshold value of the pressure sensing valve. If the cavity 701 is still inflated after the piston plate 703 has moved down to the bottom most point, the exhaust threshold is set in advance for the pressure sensor 702 below, at which point the solenoid valve 402 is opened and the medium in the cavity 701 flows out of the outlet pipe 102, and the solenoid valve 402 is closed after the pressure sensor 702 below should be below the exhaust threshold.

Example 2:

one end of the valve body 100 is an inlet pipe 101, the other end is an outlet pipe 102, the ball-type valve core 200 is arranged in the middle of the valve body 100 and used for isolating or communicating the inlet pipe 101 and the outlet pipe 102, and the valve body 100 penetrates into the valve body 100 and is connected with the ball-type valve core 200;

the lower valve cover 700 is hermetically fixed at the bottom of the valve body 100, and the lower valve cover 700 is communicated with the pressure relief unit 400 or the ball-type valve core 200 and is used for diluting a medium during exhaust in sealing;

the throat assembly 800 is used to control the flow rate of the media when the ball valve is open.

referring to fig. 9-11, in embodiment 2 based on embodiment 1 but different from it, the inlet pipe 101 of the valve body 100 is provided with a throat assembly 800, and the throat assembly 800 is used for changing the flow rate of the medium passing through the middle part of the valve body 100 to achieve the purpose of medium dilution.

Specifically, the throat assembly 800 includes a sleeve 801 and throat plates 802, the sleeve 801 is sleeved outside the inlet pipe 101, a heat insulation layer is wrapped outside the sleeve 801, a ring groove 803 is formed inside the sleeve 801, two throat plates 802 are symmetrically arranged in the ring groove 803, one end of each throat plate 802 is slidably connected with the inner wall of the ring groove 803 through a sliding block, and the other end of each throat plate 802 is inserted into the inlet pipe 101.

It should be noted that, the sleeve 801 is interactively connected with the inlet pipe 101, in order to avoid air leakage at the sleeve 801, slidable taper sleeves and sealing rubber strips are installed at two ends of the sleeve 801, a sealant is attached to two sides of the edge of the sleeve 801, the sealing rubber strips are extruded when the two taper sleeves approach the sleeve 801 at the same time, and the sleeve 801 is fixed and sealed through interference fit of the sealing rubber strips and the taper sleeves. And the sleeve 801 is slidably adjusted after the tapered sleeve is removed to both sides.

It should be noted that the throat plate 802 is inserted into the inlet tube 101 in an inclined manner, so that the throat plate 802 is in contact with the medium in an inclined manner, and the medium is restricted but not blocked.

When the moving sleeve 801 approaches the valve body 100, the throat plate 802 inclines and continuously extends towards the interior of the inlet pipe 101, and the two throat plates 802 extending to the interior of the inlet pipe 101 perform certain blocking on media, so that the air flow speed of the passing ball-type valve core 200 is increased.

The bottom end of the ball valve core 200 is provided with a first limiting hole 201, the lower valve cover 700 is provided with a second limiting hole 705 communicated with the first limiting hole 201, and the end of the second limiting hole 705 is connected with an air inlet pipe 706.

In specific implementation, the throat plate 802 is used for changing the air flow passing through the ball valve core 200, so that the negative pressure value inside the ball valve core 200 is increased, and the dilution medium is accelerated to be mixed into the middle of the ball valve core 200 from the air inlet pipe 706 upwards.

In some embodiments, a check valve 202 may be installed inside the first limiting hole 201. The initial control throat 802 does not extend into the inlet pipe 101 and a steady negative pressure flow flows through the ball-type valve cartridge 200. When dilution is required, the throat plate 802 extends towards the interior of the inlet pipe 101, increasing the negative pressure value inside the ball valve cartridge 200, forcing the check valve 202 open to collect the dilution medium.

Example 3:

referring to fig. 12-13, in a self-embodiment, embodiment 1 is combined with embodiment 2. What needs to be changed is that an air inlet pipe 706 penetrates through the middle of the lower valve cover 700, the piston plate 703 is designed in an annular shape, and the pressure sensor 702 is arranged in a staggered central position. Not only can realize sealing and pressure relief, but also can dilute the medium during exhaust.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not cause the essence of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-temperature ball valve comprises a valve body (100), a ball valve core (200) and a valve rod (300);

the ball-type valve core (200) is arranged in the valve body (100), the valve body (100) penetrates into the valve body (100) to be connected with the ball-type valve core (200);

it is characterized by also comprising:

a pressure release unit (400) which is installed inside the valve body (100) and used for releasing pressure to the medium;

the sealing assembly (500) is arranged in the valve body (100) and is in contact with the ball valve core (200) for sealing the ball valve core (200), and the sealing assembly (500) is communicated with the pressure relief unit (400) to receive a part of pressure relief medium;

the upper valve cover (600) is hermetically fixed at the top of the valve body (100) and is penetrated by the valve rod (300);

the lower valve cover (700) is hermetically fixed at the bottom of the valve body (100), and the lower valve cover (700) is communicated with the pressure relief unit (400) or the ball-type valve core (200) and is used for medium decompression during sealing or dilution during medium discharge.

2. The cryogenic ball valve according to claim 1, wherein a first limiting groove (103) and a second limiting groove (104) are formed in the ball cavity of the valve body (100) adjacent to the inlet pipe (101) and the outlet pipe (102), respectively, the first limiting groove (103) and the second limiting groove (104) are used for installing the sealing assembly (500), the first limiting groove (103) is communicated with the interior of the inlet pipe (101), and the second limiting groove (104) is communicated with the interior of the outlet pipe (102).

3. The low-temperature ball valve according to claim 2, wherein pressure relief grooves (105) are formed in the upper and lower sides of the valve body (100), a first annular pipeline (106) is formed in the inlet pipe (101), a second annular pipeline (107) is formed in the outlet pipe (102), and the first annular pipeline (106) and the second annular pipeline (107) are respectively communicated with the adjacent pressure relief grooves (105).

4. A cryogenic ball valve according to claim 3, wherein the pressure relief unit (400) comprises a pressure valve (401), a solenoid valve (402); the pressure valve (401) is mounted on the inlet pipe (101) and is controlled to communicate with the first annular duct (106), and the solenoid valve (402) is mounted on the outlet pipe (102) and is controlled to communicate with the second annular duct (107).

5. A cryogenic ball valve according to claim 4, wherein the pressure valve (401) comprises a sealing rod (403), a spring (404); the sealing rod (403) penetrates through the first annular pipeline (106) and penetrates through the wall of the inlet pipe (101), and the spring (404) is fixed on the outer side of the sealing rod (403) and fixed with the outer wall of the inlet pipe (101).

6. A cryogenic ball valve according to claim 3, wherein the sealing assembly (500) comprises a sealing strip (501) and a sealing air bag (502), the sealing strip (501) is mounted inside the first limiting groove (103), the sealing air bag (502) is mounted inside the second limiting groove (104), the sealing air bag (502) is communicated with the pressure relief groove (105) through an air pipe, and the sealing air bag (502) is filled with fluffy materials for expanding the sealing air bag.

7. The cryogenic ball valve according to claim 3, wherein a cavity (701) is formed in the lower valve cover (700), the cavity (701) is provided with a pressure sensor (702), a piston plate (703) is movably arranged in the cavity (701), the side of the cavity (701) is provided with an opening and is communicated with the pressure relief groove (105), and an inflation pipe (704) capable of introducing gas into the cavity (701) is arranged at the bottom of the lower valve cover (700).

8. The cryogenic ball valve according to claim 1, further comprising a throat assembly (800), wherein the throat assembly (800) is used for controlling the flow rate of a medium when the ball valve is opened, and comprises a sleeve (801) and a throat plate (802), the sleeve (801) is sleeved outside the inlet pipe (101), an annular groove (803) is formed in the sleeve (801), one end of the throat plate (802) is connected with the inclined inner wall of the annular groove (803) in a sliding mode through a sliding block, and the other end of the throat plate penetrates into the inlet pipe (101).

9. The low-temperature ball valve according to claim 8, wherein a first limiting hole (201) is formed in the bottom end of the ball valve core (200), and a one-way valve (202) is installed inside the first limiting hole (201).

10. The low-temperature ball valve according to claim 9, wherein the lower valve cover (700) is provided with a second limiting hole (705) communicated with the first limiting hole (201), and the end of the second limiting hole (705) is connected with an air inlet pipe (706).