A stop valve suitable for low temperature medium

Abstract

The invention discloses a stop valve suitable for low-temperature media, belongs to the field of valve technology, and is a structural improvement for a stop valve for conveying low-temperature media. Refrigerant is filled in a damping cavity corresponding to a valve seat and inside the valve seat to keep the pressure and temperature of the valve body liquid inlet relatively stable, and avoid deformation of the valve core and the valve seat sealing surface due to excessive temperature changes to produce a gap. After the valve is started, the valve core moves upward to maintain a normal opening, and relies on a telescopic buffer structure and turbine blades arranged at the upper and lower ends of the valve core to reduce the strong pressure on the valve core caused by instantaneous hydraulic pressure. Specifically, the turbine blades move downward by relying on the reverse compression effect of the telescopic air sleeve rod. When the valve core opening is maximum, the turbine blades are close to the valve seat, and rely on the low-temperature medium to drive the turbine blades to rotate, thereby consuming part of the kinetic energy in the medium, and passive flow limiting is used to reduce the impact of the high-speed fluid medium on the valve core and the outlet pipe fittings.

Description

Technical Field

[0001] The present invention relates to the field of valve technology, and more particularly to a stop valve suitable for low-temperature media. Background Art

[0002] With the development of science and technology, more and more industries are applying cryogenic media such as liquid hydrogen, liquid oxygen and liquid nitrogen, and cryogenic stop valves are being used in cryogenic medium storage and transportation equipment such as storage tanks, tank trucks, tank containers and other cryogenic pressure vessels to control the opening and closing operations of cryogenic pressure vessel pipelines.

[0003] After searching, the invention patent with patent publication number CN116292931A introduces a liquid hydrogen low-temperature stop valve. A valve body extension tube is provided on the outer wall of the valve stem, and a guide insulation ring is provided between the valve stem and the valve body extension tube to reduce the heat convection of the liquid hydrogen medium in the valve, so that the sealing bellows and other sealing components are within a safe working temperature range.

[0004] However, in the actual application of the invention, heat transfer can be reduced to a certain extent by increasing the length of the valve stem and adding thermal insulation materials to the outside of the valve stem. However, under low-temperature conditions, the thermal expansion and contraction effects of the medium are more obvious, which can easily cause the sealing surface of the sealing structure such as the valve core to deform or be damaged, thereby affecting its sealing effect. In addition, when the low-temperature medium flows through the valve, pressure fluctuations may occur due to various reasons. The large hydraulic pressure difference will directly increase the workload of the sealing structure inside the valve body, which can easily lead to a significant reduction in the sealing performance of the valve core and valve stem relative to the valve body.

[0005] Therefore, we propose a stop valve suitable for low-temperature media in response to the existing problems. Summary of the invention

[0006] The purpose of the present invention is to solve the problem that the sealing performance of the sealing structure of the existing stop valve is more easily affected under low temperature conditions, and to provide a stop valve suitable for low temperature media compared to the prior art.

[0007] The object of the present invention can be achieved by the following technical scheme: A stop valve suitable for low-temperature medium, comprising a valve body, a valve cover and a valve stem, wherein the bottom end of the valve stem is provided with a valve core extending into the inside of the valve body, and the inside of the valve body is provided with a valve seat adapted to the valve core, and the internal space of the valve seat corresponding to the liquid inlet of the valve body is set as a damping cavity, and the inner wall of the damping cavity and the inside of the valve seat are filled with refrigerant;

[0008] The upper end of the valve core is fixedly connected with an upper sealing cover which is arranged coaxially therewith, the bottom end of the valve cover is provided with a sealing ring groove corresponding to the position of the upper sealing cover, the bottom end of the valve core is movably connected with a movable sheet, the bottom end of the movable sheet is rotatably mounted with a turbine blade, the bottom end of the valve cover is provided with a buffer cavity located inside the sealing ring groove, and both sides of the buffer cavity are fixed with telescopic air-distributing sleeve rods which are symmetrically distributed on the left and right sides of the valve stem and the lower end of which is connected to the upper end of the valve core, a push rod is movably sleeved in the telescopic end of the telescopic air-distributing sleeve rod, and the bottom end of the push rod passes through the valve core and is connected to the upper end of the movable sheet.

[0009] Furthermore, the height of the sealing ring groove is greater than the height of the upper sealing cover, and a buffer spring 1 located at the top of the upper sealing cover is sleeved inside the sealing ring groove.

[0010] Furthermore, the valve core comprises an upper disc sealing portion and a lower conical sealing portion, and a conical sealing groove matching the lower conical sealing portion is provided inside the valve seat.

[0011] Furthermore, an inner groove is provided on the inner side of the upper disc sealing portion, and an outer convex ring is provided on the outer side of the upper disc sealing portion, which is adjacent to the inner groove and protrudes downward, and the cross-section of the outer edge of the outer convex ring and the inner edge of the inner groove forms an S-shaped structure, and the inner and outer sides of the valve seat are respectively provided with an inner convex ring and an outer groove that are compatible with the inner groove and the outer convex ring.

[0012] Furthermore, the movable sheet is a truncated cone-shaped structure connected to the bottom end of the lower conical sealing portion, and the outer diameter length of the turbine blade is smaller than the outer diameter length of the lowermost outlet of the conical sealing groove.

[0013] Furthermore, the telescopic air sleeve rod includes an upper rod body fixed at the bottom of the buffer cavity, an air cavity is opened in the upper rod body, a lower rod body is slidably installed in the air cavity, the telescopic end of the lower rod body extends downward and is fixed to the upper end wall of the valve core, and the upper rod body and the lower rod body are externally sleeved with two buffer springs connected between the buffer cavity and the valve core.

[0014] Furthermore, a pushing cavity for the push rod to move up and down is formed at the lower end of the lower rod body, and a suction hole connected to the pushing cavity and the air cavity is formed at the upper end of the lower rod body, and the air cavity is filled with gas.

[0015] Furthermore, the inner diameter of the suction hole is smaller than the inner diameter of the pushing cavity, and the length of the suction hole is greater than the length of the pushing cavity.

[0016] Furthermore, the upper end of the valve cover is provided with a long-necked sleeve extending upward, and an inner insulation sleeve and an outer insulation sleeve covering the outside of the valve stem are embedded and installed inside the long-necked sleeve, and the outer insulation sleeve is located above the inner insulation sleeve and extends to the outside of the long-necked sleeve.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] (1) This scheme is to improve the structure of the stop valve for conveying low-temperature media. The internal space of the valve seat corresponding to the valve body liquid inlet is set as a shock-absorbing chamber. The inner wall of the shock-absorbing chamber and the inside of the valve seat are filled with refrigerant to keep the pressure and temperature of the valve body liquid inlet relatively stable, avoiding the deformation of the valve core and the valve seat sealing surface due to excessive temperature changes and the generation of gaps. After the valve is started, the valve core moves upward to maintain the normal opening, relying on the telescopic buffer structure and turbine blades set at the upper and lower ends of the valve core to reduce the strong pressure on the valve core caused by the instantaneous hydraulic pressure;

[0019] The process of limiting the flow of turbine blades is specifically manifested as follows: when the valve core drives the telescopic air sleeve rod to contract upward, the turbine blades move downward by relying on the reverse air compression effect of the telescopic air sleeve rod. When the valve core is opened to the maximum, the turbine blades are close to the valve seat. When the low-temperature medium flows through the turbine blades at high speed, the turbine blades are driven to rotate, thereby consuming part of the kinetic energy in the fluid medium to reduce the impact force of the high-speed fluid medium on the valve core and the outlet pipe fittings.

[0020] (2) Compared with the traditional simple sealing surface structure, this scheme also optimizes and improves the structure of the valve core and the valve seat interface. The interface between the lower conical sealing part and the conical sealing groove of the valve seat is used as the main sealing surface, and the annular curved surface formed by the upper disc sealing part and the upper surface of the valve seat is used as the auxiliary sealing surface to improve the sealing performance of the valve core and the valve seat after docking. In addition, an upper sealing cover adapted to the sealing ring groove is added to the upper end of the valve core. When the valve core is in the closed state, the upper end of the upper sealing cover is sealed in the sealing ring groove to form an additional sealing surface in the flow space of the valve inlet and outlet, thereby further improving the sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the external structure of the present invention;

[0022] Figure 2 is a cross-sectional view inside the valve body of the present invention;

[0023] Figure 3 It is an overall cross-sectional view of the present invention;

[0024] Figure 4 is an internal cross-sectional view of the present invention;

[0025] Figure 5 It is a structural schematic diagram of the valve cover, valve core and valve seat of the present invention when they are detached;

[0026] Figure 6 A top view of the valve core and valve seat of the present invention when they are separated;

[0027] Figure 7 It is a cross-sectional view of the junction between the valve core and the telescopic air sleeve rod of the present invention;

[0028] Figure 8 It is a cross-sectional view of the junction between the valve core and the telescopic air sleeve rod after the valve core is lifted upwards in the present invention;

[0029] Fig. 9 It is a schematic diagram of the fluid flow direction when the valve core is opened to the maximum according to the present invention.

[0030] Description of the numbers in the figure:

[0031] 1. Valve body; 2. Valve cover; 201. Sealing ring groove; 3. Valve stem; 4. Valve core; 401. Inner groove; 402. Outer convex ring; 5. Valve seat; 501. Inner convex ring; 502. Outer groove; 6. Movable sheet; 7. Turbine blade; 8. Upper sealing cover; 9. Telescopic cloth air sleeve rod; 91. Upper rod body; 911. Air cavity; 92. Lower rod body; 921. Suction hole; 922. Pushing cavity; 93. Buffer spring 2; 10. Push rod; 11. Buffer spring 1; 12. Long-necked sleeve; 13. Inner insulation sleeve; 14. Outer insulation sleeve. DETAILED DESCRIPTION

[0032] The following will combine the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all the embodiments. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0033] Embodiment 1: Under low temperature conditions, the thermal expansion and contraction effect of the medium is more obvious, which can easily cause the sealing surface of the valve core and other sealing structures to deform or be damaged, affecting its sealing effect. When the low-temperature medium flows through the valve at a high speed, pressure fluctuations may occur due to various reasons. A large hydraulic pressure difference will directly increase the workload of the sealing structure inside the valve body. The following technical solutions are proposed:

[0034] This embodiment discloses a stop valve suitable for low temperature media. Figure 1-4 , comprising a valve body 1, a valve cover 2 and a valve stem 3, a hand wheel is arranged at the top of the valve stem 3, and the hand wheel is used as a driving structure for the valve stem 3 to rise and fall, a valve core 4 is arranged at the bottom of the valve stem 3 and extends into the interior of the valve body 1, a valve seat 5 adapted to the valve core 4 is arranged inside the valve body 1, and the internal space of the valve seat 5 corresponding to the liquid inlet of the valve body 1 is arranged as a damping cavity, and the inner wall of the damping cavity and the interior of the valve seat 5 are filled with refrigerant;

[0035] A cavity is opened in the damping cavity and the inner wall of the valve seat 5, and a proper amount of refrigerant is filled in the cavity. The filling of the refrigerant does not affect the overall hardness requirement of the valve. Filling the refrigerant can keep the pressure and temperature in the damping cavity and the valve seat 5 relatively stable, avoiding deformation of the valve sealing structure due to temperature changes. In addition, the refrigerant filled at the valve inlet can play a buffering role, absorb and dissipate part of the pressure fluctuations, make the pressure before and after the valve more stable, reduce the impact on the internal structure of the valve and the pipeline system, and improve the stability of the entire system.

[0036] The upper end of the valve cover 2 is provided with a long-necked sleeve 12 extending upward, and an inner thermal insulation sleeve 13 and an outer thermal insulation sleeve 14 covering the outside of the valve stem 3 are embedded and installed inside the long-necked sleeve 12. The outer thermal insulation sleeve 14 is located above the inner thermal insulation sleeve 13 and extends to the outside of the long-necked sleeve 12. The long-necked valve cover structure is adopted, and the inner thermal insulation sleeve 13 and the outer thermal insulation sleeve 14 are cooperated to form a low-temperature isolation cavity, which can reduce the transmission of external heat.

[0037] See also Figure 2-Figure 5 The upper end of the valve core 4 is fixedly connected with an upper sealing cover 8 which is arranged coaxially therewith. A sealing ring groove 201 corresponding to the position of the upper sealing cover 8 is opened at the bottom end of the valve cover 2. The height of the sealing ring groove 201 is greater than the height of the upper sealing cover 8. A buffer spring 11 located at the top of the upper sealing cover 8 is sleeved inside the sealing ring groove 201. The upper space on the side of the valve seat 5 corresponding to the liquid outlet of the valve body 1 can be used as a circulation space for the fluid to circulate inside and outside. The upper sealing cover 8 is placed in the circulation space when the valve is closed, and the fluid is discharged through the open valve seat 5, the circulation space and the liquid outlet of the valve body 1.

[0038] See also Figure 4-Figure 7 The valve core 4 includes an upper disc sealing portion and a lower conical sealing portion, a conical sealing groove matched with the lower conical sealing portion is provided inside the valve seat 5, an inner groove 401 is provided on the inner side of the upper disc sealing portion, an outer convex ring 402 adjacent to the inner groove 401 and protruding downward is provided on the outer side of the upper disc sealing portion, and the cross section of the outer edge of the outer convex ring 402 and the inner edge of the inner groove 401 form an S-shaped structure, and an inner convex ring 501 and an outer groove 502 matched with the inner groove 401 and the outer convex ring 402 are provided inside and outside the valve seat 5 respectively;

[0039] Compared with the traditional simple sealing surface structure, the butt surface structure of the valve core 4 and the valve seat 5 is optimized and improved;

[0040] When the valve is closed, the hand wheel is used as the driving component for the valve stem 3 to move up and down, and the valve stem 3 drives the valve core 4 to move downward until the valve core 4 and the valve seat 5 are sealed and docked. The lower conical sealing part and the butt joint surface of the conical sealing groove of the valve seat 5 are used as the main sealing surface, and the annular curved surface formed by the upper disc sealing part and the valve seat 5 is used as the auxiliary sealing surface to form a double sealing surface, thereby improving the sealing performance of the valve core 4 and the valve seat 5 after docking;

[0041] It should be added here that the conical sealing surface where the lower conical sealing portion and the valve seat 5 are connected is made of a material with good low-temperature performance and wear resistance, such as cobalt-based cemented carbide, which is welded on the sealing surface, and the outer end surfaces of the inner convex ring 501 and the outer convex ring 402 are coated with soft materials such as rubber and polytetrafluoroethylene, in the form of a soft and hard combined seal, to improve the sealing effect of the valve core 4 under low-temperature conditions.

[0042] When the valve core 4 is in a closed state, the upper end of the upper sealing cover 8 is sealed in the sealing ring groove 201 to form an additional sealing surface in the flow space of the valve inlet and outlet, thereby further improving the sealing effect.

[0043] When the valve is in the open state, the hand wheel is driven, the valve stem 3 moves upward, and the valve core 4 and the valve seat 5 gradually separate until the upper end wall of the valve core 4 contacts the lower end wall of the valve cover 2. In this process, the upper sealing cover 8 moves upward into the sealing ring groove 201 synchronously to compress the buffer spring 11. The compression deformation of the buffer spring 11 has a buffering effect on the upward movement of the valve core 4, thereby opening the flow space between the inlet and outlet of the valve.

[0044] Embodiment 2: Based on Embodiment 1, this embodiment adds a buffer flow limiting structure at the upper and lower ends of the valve core 4 to improve the impact performance of the valve core 4 in dealing with high-speed fluid media after opening, as follows:

[0045] See also Figure 4-7 The bottom end of the valve core 4 is movably connected with a movable piece 6, and the bottom end of the movable piece 6 is rotatably installed with a turbine blade 7. The movable piece 6 is a truncated cone structure connected to the bottom end of the lower conical sealing part. The outer diameter length of the turbine blade 7 is smaller than the outer diameter length of the lower end outlet of the conical sealing groove.

[0046] A buffer cavity located inside the sealing ring groove 201 is opened at the bottom end of the valve cover 2, and telescopic air-distributing sleeve rods 9 are fixed on both sides of the buffer cavity, which are symmetrically distributed on the left and right sides of the valve stem 3 and the lower end of which is connected to the upper end of the valve core 4. A push rod 10 is movably sleeved in the telescopic end of the telescopic air-distributing sleeve rod 9, and the bottom end of the push rod 10 penetrates the valve core 4 and is connected to the upper end of the movable sheet 6.

[0047] For details, please refer to Figure 7-9 The telescopic cloth air sleeve rod 9 includes an upper rod body 91 fixed to the bottom of the buffer cavity, an air cavity 911 is provided in the upper rod body 91, a lower rod body 92 is slidably installed in the air cavity 911, the telescopic end of the lower rod body 92 extends downward and is fixed to the upper end wall of the valve core 4, and the upper rod body 91 and the lower rod body 92 are sleeved with a buffer spring 93 connected between the buffer cavity and the upper end wall of the valve core 4, a pushing cavity 922 for the push rod 10 to move up and down is provided at the lower end of the lower rod body 92, and a suction hole 921 connected to the pushing cavity 922 and the air cavity 911 is provided at the upper end of the lower rod body 92;

[0048] The air cavity 911 is filled with gas, and the gas can flow through the air cavity 911, the suction hole 921 and the pushing cavity 922. The inner diameter of the suction hole 921 is smaller than the inner diameter of the pushing cavity 922, and the length of the suction hole 921 is larger than the length of the pushing cavity 922. The internal volumes of the suction hole 921 and the pushing cavity 922 are smaller than the internal volume of the air cavity 911. Therefore, when the lower rod body 92 is completely pushed into the air cavity 911, the gas inside the air cavity 911 is squeezed into the suction hole 921 and the pushing cavity 922. The gas in the suction hole 921 and the pushing cavity 922 is in a compressed state, thereby exerting an extrusion force on the push rod 10 to push downward.

[0049] The scheme in the process of valve opening is as follows: the valve core 4 moves upward with the valve stem 3 and gradually separates from the valve seat 5, at which time the lower rod body 92 is pushed into the air cavity 911 of the upper rod body 91, and the gas in the air cavity 911 is gradually compressed. After the gas in the air cavity 911 is compressed, it is reversely squeezed into the pushing cavity 922 through the suction hole 921, so that during the upward movement of the valve core 4, the gas is compressed and squeezed into the pushing cavity 922, so that the push rod 10 drives the movable sheet 6 and the turbine blade 7 to move downward;

[0050] It should be further explained that this process is in the process of gradually opening the circulation space, and the fluid medium continues to flow out through the circulation space of the valve body 1, so that the pressure on the turbine blades 7 and the movable sheet 6 gradually decreases, and the movable sheet 6 and the turbine blades 7 thereunder can move downward smoothly under the push of the reverse air pressure, and the valve core 4 gradually opens upward, and the turbine blades 7 move upward with the valve core 4 in the circulation space. When the low-temperature fluid medium flows through the turbine blades 7 at high speed, the turbine blades 7 are driven to rotate, thereby consuming part of the kinetic energy of the fluid medium, until the valve core 4 is opened to the maximum, the turbine blades 7 move downward under the action of the reverse air pressure and just act on the circulation space near the valve seat 5, and the continuously flowing fluid medium fully acts on the turbine blades 7, and the rotating turbine blades 7 continuously consume the kinetic energy of the fluid medium to reduce the impact force of the high-speed fluid medium on the valve core 4 and the outlet pipe fittings.

[0051] The scheme during the valve closing process is as follows: the valve stem 3 pushes the valve core 4 downward, gradually reducing the flow space until the valve core 4 and the valve seat 5 are sealed and connected;

[0052] In this process, on the one hand, relying on the buffering effect of the buffer spring 11 and the telescopic air sleeve rod 9, the stability of the downward movement of the valve core 4 is improved compared with the valve core 4 acting only on the valve stem 3, and the rotating turbine blades 7 continue to reduce the impact of the fluid medium on the valve core 4 until the valve core 4 is completely sealed and docked with the valve seat 5;

[0053] On the other hand, because the circulation space gradually shrinks, the fluid medium gradually becomes difficult to discharge, so that the turbine blades 7 and the movable sheet 6 will be subjected to greater upward pressure. The movable sheet 6 squeezes a pair of push rods 10 to reset upward to the pushing chamber 922, and the lower rod body 92 slides downward inside the upper rod body 91, and a negative pressure state is formed inside the air chamber 911. The compressed gas in the pushing chamber 922 is re-replenished into the air chamber 911, which not only facilitates the reset between the movable sheet 6 and the valve core 4, but also restores the gas distribution in the telescopic air sleeve rod 9, so that the inside of the telescopic air sleeve rod 9 is in a stable state, so as to prepare for the next valve opening.

[0054] In summary, the stop valve suitable for low-temperature medium working conditions is improved in structure, the internal space of the valve seat 5 corresponding to the liquid inlet of the valve body 1 is set as a damping cavity, and the refrigerant is filled in the inner wall of the damping cavity and the inside of the valve seat 5 to keep the pressure and temperature of the internal space of the valve body 1 near the liquid inlet relatively stable, so as to avoid deformation of the sealing surfaces of the valve core 4 and the valve seat 5 due to temperature changes and generate gaps;

[0055] Secondly, a movably mounted turbine blade 7 is added to the bottom end of the valve core 4, and an upper sealing cover 8, a buffer spring and a pair of telescopic air sleeve rods 9 are added to the upper end of the valve core 4 to form a buffer structure. After the valve is started, the valve core 4 moves upward with the valve stem 3. On the one hand, the strong pressure on the valve core 4 caused by the instantaneous hydraulic pressure is reduced on the basis of maintaining the normal opening of the valve core 4. On the other hand, relying on the reverse compression effect of the telescopic air sleeve rod 9, the turbine blade 7 moves downward to act on the flow space of the inlet and outlet. When the low-temperature medium flows through the turbine blade 7 at a high speed, the turbine blade 7 is driven to rotate, thereby consuming part of the kinetic energy in the medium to reduce the impact force of the high-speed medium on the valve core 4 and the outlet pipe fittings.

[0056] The above are only preferred specific implementation modes of the present invention; however, the protection scope of the present invention is not limited thereto; any technician familiar with the technical field within the technical scope disclosed by the present invention; any equivalent replacement or change based on the technical solution and improved concept of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A stop valve suitable for low-temperature media, comprising a valve body (1), a valve cover (2) and a valve stem (3), wherein the bottom end of the valve stem (3) is provided with a valve core (4) extending into the interior of the valve body (1), and the interior of the valve body (1) is provided with a valve seat (5) adapted to the valve core (4), characterized in that: The internal space of the valve seat (5) corresponding to the liquid inlet of the valve body (1) is configured as a damping cavity, and the damping cavity and the interior of the valve seat (5) are both filled with refrigerant; The upper end of the valve core (4) is fixedly connected to an upper sealing cover (8) arranged coaxially therewith, the bottom end of the valve cover (2) is provided with a sealing ring groove (201) corresponding to the position of the upper sealing cover (8), the bottom end of the valve core (4) is movably connected to a movable plate (6), the bottom end of the movable plate (6) is rotatably mounted with a turbine blade (7), the bottom end of the valve cover (2) is provided with a buffer cavity located inside the sealing ring groove (201), both sides of the buffer cavity are fixed with telescopic air-distributing sleeve rods (9) symmetrically distributed on the left and right sides of the valve stem (3) and the lower end of which is connected to the upper end of the valve core (4), the telescopic end of the telescopic air-distributing sleeve rod (9) is movably sleeved with a push rod (10), the bottom end of the push rod (10) passes through the valve core (4) and is connected to the upper end of the movable plate (6).

2. A stop valve suitable for low temperature media according to claim 1, characterized in that: The height of the sealing ring groove (201) is greater than the height of the upper sealing cover (8), and a buffer spring 1 (11) located at the top of the upper sealing cover (8) is sleeved inside the sealing ring groove (201).

3. A stop valve suitable for low temperature media according to claim 1, characterized in that: The valve core (4) comprises an upper disc sealing portion and a lower conical sealing portion, and a conical sealing groove matching the lower conical sealing portion is provided inside the valve seat (5).

4. A stop valve suitable for low temperature media according to claim 3, characterized in that: An inner groove (401) is provided on the inner side of the upper disc sealing portion, and an outer convex ring (402) is provided on the outer side of the upper disc sealing portion, which is adjacent to the inner groove (401) and protrudes downward. The cross-section of the outer edge of the outer convex ring (402) and the inner edge of the inner groove (401) form an S-shaped structure. The inner and outer sides of the valve seat (5) are respectively provided with an inner convex ring (501) and an outer groove (502) that are compatible with the inner groove (401) and the outer convex ring (402).

5. A stop valve suitable for low temperature medium according to claim 4, characterized in that: The movable sheet (6) is a truncated cone-shaped structure connected to the bottom end of the lower conical sealing portion, and the outer diameter length of the turbine blade (7) is smaller than the outer diameter length of the outlet at the bottom end of the conical sealing groove.

6. A stop valve suitable for low temperature media according to claim 1, characterized in that: The telescopic air sleeve rod (9) comprises an upper rod body (91) fixed to the bottom of the buffer cavity, an air cavity (911) is provided in the upper rod body (91), a lower rod body (92) is slidably mounted in the air cavity (911), a telescopic end of the lower rod body (92) extends downward and is fixed to the upper end wall of the valve core (4), and a buffer spring (93) connected between the buffer cavity and the valve core (4) is sleeved on the outside of the upper rod body (91) and the lower rod body (92).

7. A stop valve suitable for low temperature media according to claim 6, characterized in that: The lower end of the lower rod body (92) is provided with a pushing cavity (922) for the push rod (10) to move up and down, and the upper end of the lower rod body (92) is provided with a suction hole (921) connected to the pushing cavity (922) and the air cavity (911), and the air cavity (911) is filled with gas.

8. A stop valve suitable for low temperature media according to claim 7, characterized in that: The inner diameter of the suction hole (921) is smaller than the inner diameter of the material pushing cavity (922), and the length of the suction hole (921) is greater than the length of the material pushing cavity (922).

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