A cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing

Abstract

The present invention relates to a cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing, comprising: a valve base, a valve stem, a bellows and a gas source device; the valve base has a liquid accumulation cavity, and the liquid accumulation cavity has a cavity throat with a radially reduced size; part of the valve stem extends into the liquid accumulation cavity and is used to cooperate with the cavity throat to control the size of the flow area, and the rest of the valve stem is outside the valve base; one end of the bellows is connected to the end of the valve base, and the other end is connected to the end of the valve stem; the valve base is provided with a first channel for communicating the inside and outside of the bellows; the valve stem is provided with a second channel for communicating the inside and outside of the bellows; the gas source device includes: a first gas source module, a second gas source module and a throttling module; the first gas source module and the second gas source module are selectively connected to the inlet of the throttling module respectively; the outlet of the throttling module is connected to the port of the first channel or the second channel for gas replacement of the hollow part of the bellows.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and particularly to a cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing. Background Art

[0002] During the ground test or actual flight of a cryogenic variable-thrust engine, it is necessary to undergo long-term pre-cooling with cryogenic media, cooling the pipeline from the storage tank to the engine below the saturation temperature of the media. Generally, liquid oxygen is at -170°C, methane is at -150°C, and the simulated medium liquid nitrogen is at -190°C. The pre-cooling time is about 1 to 2 hours or even longer. The long-term cryogenic pre-cooling will cause water vapor in the air to freeze on the surface of the valve stem, thereby affecting the normal operation and reliability of the valve. On the one hand, cryogenic jamming will affect the propellant flow rate into the engine, and on the other hand, it may even cause the valve to fail to open or close normally according to the timing sequence, resulting in an accident of engine damage. In addition, the ice formation on the valve stem surface will enter the valve interior during the movement of the valve stem, damaging the dynamic sealing structure in the valve, and thus leading to the serious consequence of propellant leakage.

[0003] Currently, in aircraft or ground tests, there are mainly two anti-icing solutions: The first is a preventive approach, specifically using hydrophobic coatings, special waterproof materials, surface micro-nano structures, vacuum-sealed environments, etc. for pre-prevention; the second is post-icing de-icing, specifically using external methods such as electric heating, large-flow gas blowing, mechanical de-icing, and thermal de-icing as de-icing methods.

[0004] For a real cryogenic engine supply system, its working environment is harsh. The valve is in an extremely low temperature and long-term cooling situation, and the air humidity on the surface of the valve stem is high, which is extremely likely to cause serious icing. Therefore, cryogenic valves are usually large in volume and mass, with a stuffing box of sufficient length to reduce the heat conduction of the valve stem. In the first solution, since the valve stem is a movable surface, it is difficult to create a vacuum environment to isolate water vapor, and using coatings and micro-structures will cause wear on the sealing surface. In the second solution, the interior of the valve is a large-flow cryogenic propellant fuel / oxidant. Once there is a leak and an ignition source, it will cause an explosion. Methods such as electric heating de-icing will introduce potential hazards. In the case of serious icing, simply blowing with gas will consume a large amount of gas, and it is impossible to carry a large amount of blowing gas under the payload constraints of a real aircraft. Moreover, in the electric heating solution, an additional power source needs to be carried, and regular charging and discharging and maintenance are required, which will reduce the reliability of the system and increase its complexity.

[0005] It can be seen that in the existing technical solutions, cryogenic valves have problems such as large volume, heavy weight, complex de-icing methods, and large gas consumption, making it difficult to meet the requirements of miniaturization and integration of cryogenic systems. Moreover, some solutions require additional power sources and regular maintenance, which cannot meet the constraints of ground tests and real aircraft. And these solutions greatly increase the launch dead weight and launch cost of related vehicles, and are also not conducive to the overall layout of the system. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing to solve the low-temperature icing and frost formation on the valve stem caused by real cryogenic propellants.

[0007] To achieve the above invention object, the present invention provides a cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing, including: a valve base, a valve stem movably connected to the valve base, a bellows, and a gas source device;

[0008] The valve base has a hollow liquid accumulation cavity, and the liquid accumulation cavity has a cavity throat with a radially reduced size;

[0009] A part of the valve stem extends into the liquid accumulation cavity to control the size of the flow area in cooperation with the cavity throat, and the rest of the valve stem is outside the valve base for connection with a driver;

[0010] The bellows and the valve stem are sleeved outside the valve stem at intervals; wherein, one end of the bellows is sealed and connected to the end of the valve base, and the other end is sealed and connected to the end of the valve stem outside the valve base;

[0011] The valve base is provided with a first channel for communicating the inside and outside of the bellows;

[0012] The valve stem is provided with a second channel for communicating the inside and outside of the bellows;

[0013] The gas source device includes: a first gas source module, a second gas source module, and a throttling module;

[0014] The first gas source module and the second gas source module are selectively connected to the inlet of the throttling module;

[0015] The outlet of the throttling module is connected to the port of the first channel or the second channel for gas replacement of the hollow part of the bellows.

[0016] According to one aspect of the present invention, the first channel is provided at one end of the valve base connected to the bellows; wherein, the first channel forms a first port communicating with the hollow part of the bellows on the end face of the end of the valve base, and the first channel forms a second port communicating with the outside on the radial outer side face of the end of the valve base;

[0017] The second channel forms a third port communicating with the outside on the end face of the end of the valve stem away from the valve base, and the second channel forms a fourth port communicating with the hollow part of the bellows on the radial outer side face of the valve stem;

[0018] The outlet of the throttling module is communicated with the third port or the second port.

[0019] According to one aspect of the present invention, the throttling module includes: a first docking joint, a second docking joint and a throttling structure;

[0020] The throttling structure includes: a truncated cone cylinder, a clamping and fixing ring coaxially arranged outside the large diameter end of the truncated cone cylinder, and a baffle plate coaxially arranged inside the small diameter end of the truncated cone cylinder;

[0021] The baffle plate is provided with a throttling hole penetrating through its body, and the axial direction of the throttling hole is arranged parallel to the axial direction of the truncated cone cylinder;

[0022] The first docking joint is a hollow tube, and the inner side face of one end of its hollow part is set as an annular conical surface matching the outer side face of the truncated cone cylinder for the embedding of the throttling structure;

[0023] The second docking joint is a hollow tube, and the end face of the end of the second docking joint opposite to the throttling structure is set as a spherical ring surface for abutting against the inner side of the truncated cone cylinder;

[0024] The first docking joint and the second docking joint are connected to clamp and fix the clamping and fixing ring;

[0025] The end of the second docking joint away from the throttling structure forms the inlet of the throttling module, and the end of the first docking joint away from the throttling structure forms the outlet of the throttling module.

[0026] According to one aspect of the present invention, the valve base includes: a base body, an end cover and a dynamic sealing structure;

[0027] The base body is a hollow cylindrical structure;

[0028] Along the axial direction of the base body, the hollow part of the base body includes a sealing member installation cavity and a liquid accumulation cavity connected coaxially;

[0029] One end of the seal installation cavity away from the liquid accumulation cavity forms a fifth port at one end of the base body;

[0030] One end of the liquid accumulation cavity away from the seal installation cavity forms a valve outlet at the other end of the base body;

[0031] A valve inlet communicating with the liquid accumulation cavity is provided on the radial side wall of the base body;

[0032] The valve inlet is communicated with one end where the liquid accumulation cavity is connected to the seal installation cavity;

[0033] The end cover is detachably connected to the end of the base body where the fifth port is provided, and the end cover is provided with a through hole communicating with the seal installation cavity;

[0034] The dynamic seal structure is installed in the seal installation cavity;

[0035] The valve stem sequentially passes through the through hole of the end cover and the dynamic seal structure to extend into the liquid accumulation cavity.

[0036] According to one aspect of the present invention, the bellows is sleeved outside the end cover, and the bellows is sealingly connected to the end cover;

[0037] The first channel is provided on the end cover, and a plurality of the first ports are arranged at equal intervals along the circumference on the end face of the end cover;

[0038] The second port is provided on the radial outer side surface of the end cover.

[0039] According to one aspect of the present invention, the valve stem includes: an equal-diameter section and a tapered section arranged coaxially;

[0040] The diameter of the tapered section gradually decreases along the direction away from the equal-diameter section;

[0041] The second channel is provided in the equal-diameter section;

[0042] A plurality of the fourth ports are arranged at equal intervals along the circumference of the equal-diameter section.

[0043] According to one aspect of the present invention, the dynamic seal structure includes: a spring energy storage seal ring, a first limit support member, and a second limit support member;

[0044] The first limit support member is arranged at one end where the seal installation cavity is connected to the liquid accumulation cavity, and the first limit support member is detachably connected to the seal installation cavity;

[0045] The second limit support is arranged at one end of the seal installation cavity adjacent to the end cover;

[0046] The spring energy storage seal ring is arranged between the first limit support and the second limit support, and the two opposite ends of the spring energy storage seal ring are respectively abutted against the first limit support and the second limit support.

[0047] According to one aspect of the present invention, the spring energy storage seal ring includes: an outer liner and an inner liner;

[0048] The outer liner is a PTFE outer liner;

[0049] The inner liner is a stainless steel spring inner liner, and the compression amount of the inner liner in the diameter direction is at least 5%.

[0050] According to one aspect of the present invention, the end cover is a heat-insulating non-metallic material cover, and the surface roughness Ra of the end cover is less than 1.6 microns;

[0051] The valve stem is a stainless steel metal rod, wherein the surface roughness Ra of the equal-diameter section of the valve stem is less than or equal to 0.8 microns;

[0052] The hardness of the valve stem is greater than 150 HRB;

[0053] The bellows is a PTFE material bellows;

[0054] The bellows satisfies:

[0055]

[0056] Wherein, is the length of the hollow cavity of the bellows, is the wall thickness of the bellows, is the corrugation depth of the bellows, is the minimum length of the compression of the bellows, is the maximum length of the stretching of the bellows, is the number of waves of the bellows;

[0057] The first gas source module includes: a first gas cylinder and a first control valve;

[0058] The second gas source module includes: a second gas cylinder and a second control valve;

[0059] The first gas cylinder is connected to the inlet of the throttling module based on the first control valve, and the second gas cylinder is connected to the inlet of the throttling module based on the second control valve;

[0060] The first gas cylinder stores nitrogen;

[0061] The second gas cylinder stores helium gas;

[0062] If the outlet of the throttling module is connected to the port of the first channel, the inner diameter of the first channel is greater than the aperture diameter of the throttling orifice, the inner diameter of the second channel is greater than the inner diameter of the first channel, and the opening diameter of the fourth port is less than the inner diameter of the first channel;

[0063] If the outlet of the throttling module is connected to the port of the second channel, the inner diameter of the second channel is greater than the aperture diameter of the throttling orifice, the inner diameter of the first channel is greater than the inner diameter of the second channel, and the opening diameter of the first port is less than the inner diameter of the second channel.

[0064] According to one solution of the present invention, the system uses the methods of gas dilution and displacement to prevent icing and achieve the directional discharge of leakage substances. Compared with traditional methods such as post - event de - icing, mechanical de - icing, and electro - thermal de - icing, the system of this solution has a high degree of integration, a low complexity of the system solution, a reliable implementation method. The method of taking preventive measures in advance can effectively avoid the damage to the valve stem surface and sealing components caused by post - event de - icing, and can also eliminate the potential hazards introduced by methods such as electro - thermal de - icing.

[0065] According to one solution of the present invention, two different gas sources can be used according to different mission scenarios to save test costs and launch costs. For the specific situations of ground tests and aircraft flight tests, two switchable gas sources are designed, and a throttling module is used for throttling to reduce gas consumption. Specifically, external nitrogen can be used as the gas source during ground hot - fire tests and the pre - cooling stage of the aircraft. During actual flight of the aircraft, the helium gas carried by the aircraft is used. After the aircraft leaves the atmosphere and reaches a vacuum environment, no dilution gas is required. Thus, the advantage of this setting method is that since nitrogen is cheaper than helium, and the amount of helium carried by the aircraft is not enough to cover the entire pre - cooling process, this method can save economic costs on the one hand, and on the other hand, can also reduce the dead weight of the helium gas carried by the aircraft and lower the launch cost.

[0066] According to one solution of the present invention, this solution uses a combined setting method of the valve stem, bellows, and end - cover to construct a variable - volume sealed environment. During the static and dynamic operation of the valve, an environment for diluting gas components can be created to displace water vapor, thereby avoiding icing. Among them, according to the characteristics of the reciprocating movement of the valve stem, a bellows that can be stretched and compressed at low temperatures is designed. The length and internal volume of the bellows change according to the movement of the valve stem. One end is connected to the valve stem, and the other end is connected to the end - cover, ensuring reliable sealing and realizing the creation of a sealed space.

[0067] According to one solution of the present invention, by forming a gas flow channel inside the structure, the present solution reduces the existence of the drainage pipeline and reduces the risk of leakage at the interface position. Among them, preferably, the dilution gas inlet is connected to the flow channel port on the outer side of the radial direction of the end cover, flows out through the flow channel port in the axial direction of the end cover, and the gas flowing out from the end cover can directly blow the surface of the valve stem to take away moisture and debris. Finally, the dilution gas in the sealed space inside the bellows flows out through the radial and axial flow channel structures inside the valve stem, realizing the directional discharge and treatment of moisture, debris, and leakage.

[0068] According to one solution of the present invention, the present solution adopts a dynamic sealing method for cryogenic media formed by combining an end cover, a valve stem, a spring energy storage sealing ring, and a base body. By using a valve stem with high hardness and low surface roughness, the wear of the energy storage sealing ring is reduced, and through axial compression, a sufficient compression amount of the spring energy storage sealing ring is ensured; in the radial direction, the spring energy storage ring can compensate for the deformation of the material at low temperatures, ensuring that the cryogenic propellant does not leak along the axial gap.

[0069] According to one solution of the present invention, the present solution adopts a non-metallic end cover including an internal flow channel, which can effectively reduce the heat conduction of the valve seat in one-dimensional direction and effectively improve the temperature environment inside the bellows.

[0070] According to one solution of the present invention, by arranging a plurality of ports in a ring shape on the end face of the end cover, the uniform blowing of the outer surface of the valve stem in the circumferential direction can be realized, effectively ensuring the blowing effect of the gas on the surface of the valve stem.

[0071] According to one solution of the present invention, the present invention can effectively prevent ice formation on the valve stem of the cryogenic flow regulating valve. Based on the idea of pre-icing removal, the de-icing cost is reduced, and the harm of ice jamming of the flow regulating valve is reduced; by adopting the method of switching between two gases, nitrogen / helium, the launch dead weight can be effectively reduced and the economy of de-icing can be improved; by adding a throttle orifice plate, the gas consumption can be controlled.

[0072] According to one solution of the present invention, the present system adopts a polytetrafluoroethylene bellows with good low-temperature resistance, compression and tensile properties as a solution for waterproofing, dustproofing, preventing debris, and constructing a sealed space, which can improve the low-temperature reliability of the device. At the same time, by regularly replacing and maintaining the bellows, the low-temperature working life of the device can be improved.

[0073] According to one solution of the present invention, the present solution adopts a spring energy storage sealing ring as the dynamic sealing mechanism for the operation of the valve stem, drains and dilutes the possibly existing trace leakage propellant to achieve the purpose of directional discharge. By combining dynamic sealing and directional discharge, it can prevent the propellant from gathering around the device after leakage, thus causing danger, and improve the safety and reliability of the device.

[0074] According to one aspect of the present invention, the present invention realizes the anti-icing and dynamic sealing performance of the valve stem of the flow regulating valve to achieve reliable operation at low temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 Structural diagram of the low-temperature valve assembly according to an embodiment of the present invention;

[0076] Figure 2 Structural diagram of the dynamic sealing structure according to an embodiment of the present invention;

[0077] Figure 3 Structural diagram of the throat of the cavity where the valve stem extends into the liquid accumulation cavity in the low-temperature valve assembly according to an embodiment of the present invention;

[0078] Figure 4 Structural diagram of the corrugated pipe according to an embodiment of the present invention;

[0079] Figure 5 Structural diagram of the valve stem according to an embodiment of the present invention;

[0080] Figure 6 Connection structure diagram of the low-temperature valve assembly according to an embodiment of the present invention;

[0081] Figure 7 Structural diagram of the end cover according to an embodiment of the present invention;

[0082] Figure 8 Cross-sectional view of the end cover according to an embodiment of the present invention;

[0083] Figure 9 Structural diagram of the throttling module according to an embodiment of the present invention;

[0084] Figure 10 Cross-sectional view of the throttling structure according to an embodiment of the present invention;

[0085] Figure 11 Graph showing the tensile and compressive test results of the low-temperature valve assembly according to an embodiment of the present invention under low-temperature conditions, where Figure 11 (P1) represents the state diagram of the outer wall of the corrugated pipe covered with ice and frost after the working preset time, Figure 11 (P2) represents the state diagram when the corrugated pipe is compressed to the limit, Figure 11 (P3) represents the state diagram when the corrugated pipe is stretched, Figure 11 (P4) represents the state diagram when the corrugated pipe is fully expanded. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0086] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings required for the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other accompanying drawings can be obtained based on these drawings without creative efforts.

[0087] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" is based on the orientation or positional relationship shown in the relevant accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention.

[0088] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments cannot be described in detail one by one here, but the embodiments of the present invention are not limited to the following embodiments.

[0089] Combined with Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, according to an embodiment of the present invention, a cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing includes: a valve base 1, a valve stem 2 movably connected to the valve base 1, a bellows 3 and a gas source device 4; wherein, the valve base 1 is the main body of the entire cryogenic valve assembly, and the valve stem 2 is movably connected to the valve base 1 to achieve flow control of the entire cryogenic valve assembly, while the bellows 3 and the gas source device 4 are used to achieve the anti-icing effect of the valve stem in a low-temperature environment. In this embodiment, the valve base 1 has a hollow liquid accumulation cavity, and the liquid accumulation cavity has a cavity throat with a radially reduced size; wherein, a part of the valve stem 2 extends into the liquid accumulation cavity and is used to cooperate with the cavity throat to control the size of the flow-through area, and the remaining part of the valve stem 2 is outside the valve base 1 and is used to connect to a driver; in this embodiment, the valve stem 2 can be based on an automatically controlled driver to achieve its position relative to the cavity throat in the liquid accumulation cavity, thereby achieving a change in the area of the annular gap between the valve stem 2 and the cavity throat to achieve the flow control effect on the fluid.

[0090] In this embodiment, the bellows 3 and the valve stem 2 are sleeved outside the valve stem 2 at intervals; wherein, one end of the bellows 3 is hermetically connected to the end of the valve base 1, and the other end thereof is hermetically connected to the end of the valve stem 2 outside the valve base 1; in this embodiment, the radial dimension of the bellows 3 is larger than the radial dimension of the valve stem 2. Thus, a hollow space can be formed between the bellows 3 and the valve stem 2 to facilitate storing the input replacement gas, and then an annular protective atmosphere can be formed between the valve stem 2 and the bellows 3, thereby effectively avoiding the phenomenon of icing / frosting of the valve stem 2 in a low-temperature environment, so as to fully ensure the smooth and reliable operation of the valve stem 2.

[0091] In this embodiment, an annular protrusion is provided at the position on the valve stem 2 where it is connected to the bellows 3. Thus, the bellows 3 can be sleeved on the annular protrusion to achieve the corresponding sealed connection; wherein, to ensure the connection sealing performance between the valve stem 2 and the annular protrusion, the annular protrusion can be fixed on the valve stem 2 by means of welding, interference fit connection, threaded connection, clamping, etc. Through the above settings, the bellows 3 can conveniently hermetically cover the part of the valve stem 2 exposed outside to fully close the moving stroke of the valve stem 2. Thus, after exhausting the internal air containing water vapor, the effect of preventing icing / frosting can be fully achieved.

[0092] In this embodiment, the annular protrusion provided on the valve stem 2 for connecting to the bellows 3 can be set as a stepped boss structure, wherein the small-diameter end formed on the annular protrusion faces the bellows 3. Thus, the end of the bellows 3 can be sleeved on the small-diameter end of the annular protrusion, and the corresponding fixing effect can be achieved by means of sealed connection.

[0093] Furthermore, the valve base 1 is provided with a first passage 11 for communicating the inside and outside of the bellows 3; the valve stem 2 is provided with a second passage 21 for communicating the inside and outside of the bellows 3; wherein, the gas source device 4 is connected to the port of the first passage 11 or the second passage 21 for gas replacement of the hollow part of the bellows 3. Thus, the gas source device 4 can realize the input of the replacement gas from the port of one of the passages through the port of the first passage 11 or the second passage 21, and correspondingly discharge the air inside the bellows 3 from the other passage. Thus, the water that may freeze can be fully eliminated to achieve the effect of anti-icing.

[0094] Combined Figure 1 、 Figure 2 、 Figure 3 and Figure 4As shown, according to one embodiment of the present invention, the first channel 11 is arranged at one end of the valve base 1 connected to the bellows 3; wherein the first channel 11 forms a first port connected to the hollow portion of the bellows 3 on the end face of the end of the valve base 1, and the first channel 11 forms a second port connected to the outside on the radial outer side of the end of the valve base 1.

[0095] Furthermore, the second channel 21 forms a third port connected to the outside on the end surface of the valve stem 2 away from the valve base 1 , and forms a fourth port connected to the hollow portion of the bellows 3 on the radial outer side surface of the valve stem 2 .

[0096] Therefore, by connecting the air source device 4 to the second port or the third port, the replacement gas can be made to flow in one direction, so that the air in the bellows 3 can be discharged along the flow direction of the replacement gas. In addition, the continuous delivery of replacement gas to the bellows 3 by the air source device 4 can effectively prevent the intrusion of external air, which is more beneficial to continuously ensuring the cleanliness and dryness of the surface of the valve stem 2.

[0097] Combination Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 6 As shown, according to an embodiment of the present invention, the valve base 1 includes: a base body 1a, an end cover 1b and a dynamic sealing structure 1c; in this embodiment, the base body 1a is a hollow cylindrical structure; wherein, along the axial direction of the base body 1a, the hollow portion of the base body 1a includes a coaxially connected seal installation cavity and a liquid accumulation cavity; the seal installation cavity is provided for installing the dynamic sealing structure 1c to facilitate the dynamic sealing effect of the valve stem 2 during the active adjustment process, and the role of the liquid accumulation cavity is to realize the input and output of the fluid, and then by controlling the extension length of the valve stem 2 relative to the cavity throat of the liquid accumulation cavity, the annular interval between the valve stem 2 and the cavity throat can be changed in the radial direction, thereby achieving flexible and accurate adjustment of the flow area.

[0098] In this embodiment, a fifth port is formed at one end of the base body 1a at one end of the seal installation cavity away from the liquid accumulation cavity, so that the valve stem 2 can be inserted through the provided fifth port.

[0099] Furthermore, a valve outlet 1a1 is formed at one end of the liquid accumulation chamber away from the sealing installation chamber at the other end of the base body 1a; and a valve inlet 1a2 connected to the liquid accumulation chamber is provided on the radial side wall of the base body 1a; in the present embodiment, the valve inlet 1a2 is connected to one end connected to the liquid accumulation chamber and the sealing installation chamber; wherein, the axial direction of the valve inlet 1a2 is perpendicular to the axial direction of the valve outlet 1a1, and in the present embodiment, along the axial direction of the base body 1a, the valve inlet 1a2 and the valve outlet 1a1 are respectively on opposite sides of the throat of the liquid accumulation chamber, thereby achieving a corresponding control effect under the action of the valve stem 2.

[0100] In this embodiment, the liquid accumulation cavity further includes: an input cavity portion and an output cavity portion; correspondingly, the cavity throat is located between the input cavity portion and the output cavity portion, wherein along the axial direction of the valve base 1, the length of the input cavity portion is less than the length of the output cavity portion, and the input cavity portion can be set as a cylindrical cavity with a constant radial dimension, while the output cavity portion can be set as a truncated conical cavity with a radial dimension gradually increasing in a direction away from the cavity throat. In this embodiment, the cavity throat includes: a first cone ring portion connected to the input cavity portion and a second cone ring portion connected to the output cavity portion, wherein the taper change of the second cone ring portion is consistent with the taper change of the output cavity portion, thereby achieving the continuity of the second cone ring portion and the output cavity portion. In this embodiment, the taper of the first cone ring portion is greater than the taper of the second cone ring portion, thereby causing the first cone ring portion connected to the input cavity portion to shrink rapidly in the radial direction.

[0101] In this embodiment, the end cover 1b is detachably connected to one end of the base body 1a where the fifth port is provided, and the end cover 1b is provided with a through hole which is connected to the seal installation cavity; wherein, the end cover 1b and the base body 1a can be connected by a threaded connection, or the end cover 1b and the base body 1a can be directly screwed together by a threaded connection; further, in order to ensure the smooth sliding of the valve stem 2, the through hole on the end cover 1b can be arranged coaxially with the seal installation cavity.

[0102] In this embodiment, the end cap 1b can be set as a metal end cap or a non-metal end cap. By setting the end cap 1b as a non-metal end cap, its heat conduction effect can be effectively reduced, which is beneficial to improving the temperature environment inside the bellows 3.

[0103] In this embodiment, the dynamic seal structure 1c is installed in the seal installation cavity. Thus, the valve stem 2 sequentially passes through the through-hole of the end cover 1b and the dynamic seal structure 1c to extend into the liquid accumulation cavity. Through the provided dynamic seal structure 1c, contact sealing with the valve stem 2 in the radial direction can be achieved. Thus, when the position of the valve stem 2 changes, the dynamic seal structure 1c can generate corresponding shape changes at different positions of the valve stem 2 to achieve dynamic sealing at the contact position.

[0104] Combined with Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 7 and Figure 8 As shown, the end cover 1b is preferably made of a non-metallic material. For example, it uses the non-metallic PTFE material with poor thermal conductivity. On the one hand, due to its poor thermal conductivity, it can block the heat conduction of low-temperature fluids and improve the local thermal environment. On the other hand, due to its excellent processing performance similar to that of metals, it can be turned. After turning, it has a good surface roughness. At the same time, it can adapt to a low-temperature environment of -200 °C, and its linear expansion coefficient is about 1.2 - 1.5 μm / °C. In this embodiment, the surface roughness Ra of the end cover 1b is less than 1.6 micrometers to effectively ensure the smoothness and flatness of the overall outer surface, which is beneficial to ensuring the structural airtightness of the installation position.

[0105] In this embodiment, along the circumferential direction of the end cover 1b, a plurality of through-holes for threaded connectors to pass through can be provided on the end cover 1b. Thus, it is convenient to fix the end cover 1b on the base body 1a.

[0106] In this embodiment, the first channel 11 is provided on the end cover 1b, and a plurality of first ports are arranged at equal intervals along the ring on the end face of the end cover 1b; the second port is provided on the radially outer side face of the end cover 1b. In this embodiment, if the second port is provided as a plurality, the first ports can be arranged in one-to-one correspondence with the second ports. Thus, the unified connection can be achieved by setting a plurality of connectors. Of course, the second port can also be provided as one, and the unified distribution / collection effect of gas between the second port and the plurality of first ports can be achieved by realizing the unified connection of one second port with a plurality of second ports.

[0107] Combined with Figure 7 and Figure 8As shown, preferably, there is one first channel 11, and eight first ports are provided on the end face. Among them, the second port is formed based on a channel perpendicular to the axis of the first channel 11, and its diameter is 1 mm, so as to achieve communication with the first channel 11. In this embodiment, the installation position of the first channel 11 needs to avoid the through hole on the end cover 1b for the threaded connector to pass through to prevent air leakage. Moreover, the axis of the first channel 11 is perpendicular to the axis of the end cover 1b, which is convenient for the processing and forming of the first channel 11.

[0108] Furthermore, in order to connect the second port to the first channel 11, an annular distribution cavity for connecting the second port and the first channel 11 is also provided inside the end cover 1b, thereby realizing the uniform distribution of gas.

[0109] Furthermore, the annular distribution cavity provided in the end cover 1b can form an opening on the inner ring surface of the end cover 1b. Thus, the annular distribution cavity can be blocked by the valve stem 2 passing through the end cover 1b to achieve the diversion of the airflow between the first channel 11 and the second port. Through the above settings, forming an opening for the annular distribution cavity on the inner ring surface of the end cover 1b can, on the one hand, facilitate the processing and forming of the annular distribution cavity, and on the other hand, enable the gas to directly surround the outer side of the valve stem 2, and then still have a certain protective atmosphere in the position that the bellows 3 cannot accommodate, thereby playing a preventive and promoting role in the anti-icing between the valve stem 2 and the end cover 1b, and further being more beneficial to ensuring the stable and reliable operation of the valve stem 2.

[0110] Furthermore, when the outlet of the throttling module 43 is connected to the first channel 11, that is, when the first channel 11 is used as the gas input end, the inner diameter of the first channel 11 is larger than the aperture of the throttling hole provided in the throttling module 43, thereby preventing gas congestion in the channel. At the same time, referring to Figure 6 and Figure 7 , the second port of the first channel 11 is connected to the upstream gas source device 4 by an annealed copper tube. The diameter of the annealed copper tube only needs to be larger than the diameter of the orifice plate (for example, the inner diameter of the annealed copper tube is selected as 2 mm for the outer diameter and 0.5 mm for the wall thickness, and its flow cross-section is Φ1 mm). Through the above settings, the connection method using the annealed copper tube can effectively avoid cracking during the bending process and ensure the reliability of the structure.

[0111] Combined with Figure 1 、 Figure 3 and Figure 4As shown, according to an embodiment of the present invention, the corrugated pipe 3 is sleeved outside the end cover 1b, and the corrugated pipe 3 is hermetically connected to the end cover 1b; wherein, in order to achieve a reliable fit with the end cover 1b and avoid the copper pipe connected to the second port, a U-shaped opening can be provided at the end of the corrugated pipe 3, so as to avoid the interference of the copper pipe, and the rest of the position can be installed outside the end cover 1b by means of sealed fixation. In this embodiment, the end of the corrugated pipe 3 is installed on the outside of the end cover 1b by means of transition fit; wherein, the sealed fixation method can be realized by a combination of tie strap fastening and filling with low-temperature weather-resistant glue.

[0112] In this embodiment, the corrugated pipe 3 is a PTFE material corrugated pipe to ensure its low-temperature resistance. Further, in order to ensure that the corrugated pipe 3 fully meets the control stroke of the entire low-temperature valve assembly, the corrugated pipe 3 satisfies:

[0113]

[0114] Among them, is the length of the hollow cavity of the corrugated pipe 3, is the wall thickness of the corrugated pipe 3, is the corrugation depth of the corrugated pipe 3, is the minimum compressed length of the corrugated pipe 3, is the maximum stretched length of the corrugated pipe 3, is the number of waves of the corrugated pipe 3.

[0115] Thus, the corrugated pipe 3 can be compressed to a length less than or equal to the minimum allowable length and stretched to a length greater than or equal to the maximum allowable length.

[0116] Combined with Figure 1 、 Figure 3 and Figure 5 As shown, according to an embodiment of the present invention, the valve stem 2 includes: an equal-diameter section 2a and a tapered section 2b arranged coaxially; wherein, the diameter of the tapered section 2b gradually decreases along the direction away from the equal-diameter section 2a; the tapered section 2b is provided to cooperate with the cavity throat in the liquid accumulation cavity. Among them, based on the radially variable tapered section 2b, as the length of its insertion into the cavity throat changes, the annular flow area between the tapered section 2b and the cavity throat can be flexibly adjusted.

[0117] In this embodiment, the second channel 21 is provided in the equal-diameter section 2a; wherein, the second channel 21 has an intermediate channel converging portion and a peripheral channel diverging portion; wherein, the intermediate channel converging portion is coaxially arranged with the equal-diameter section 2a and forms a third port at the end of the equal-diameter section 2a, while the peripheral channel diverging portion extends radially along the equal-diameter section 2a. Thus, one end of the peripheral channel diverging portion is connected to the intermediate channel converging portion, and the other end forms a fourth port on the outer side surface of the equal-diameter section 2a. Among them, a plurality of peripheral channel diverging portions are provided so that a plurality of fourth ports can be arranged at equal intervals in the circumferential direction of the equal-diameter section 2a. In this embodiment, as described above, preferably, the outlet of the throttling module 43 is connected to the port of the first channel 11. Then, when the inner diameter of the first channel 11 is greater than the aperture diameter of the throttling hole, and the inner diameter of the intermediate channel converging portion of the second channel 21 is greater than the inner diameter of the first channel 11, the opening diameter of the fourth port is less than the inner diameter of the first channel 11, thereby ensuring the smoothness of the air flow from the input to the output direction to fully eliminate the congestion of the air flow. Of course, in another embodiment, if the outlet of the throttling module 43 is connected to the port of the second channel 21, then the inner diameter of the second channel 21 is greater than the aperture diameter of the throttling hole, and the inner diameter of the first channel 11 is greater than the inner diameter of the second channel 21, and the opening diameter of the first port is less than the inner diameter of the second channel 21. Thus, when transporting gas in the reverse direction, the beneficial effect of eliminating the congestion of the air flow can also be achieved. In short, it is only necessary to satisfy that the sum of the volume of the upstream gas and the volume of the sealed micro-leakage gas is less than the maximum allowable gas output of the downstream.

[0118] Furthermore, the valve stem 2 can be set as a stainless steel metal rod. In order to ensure the service life, low-temperature reliability, and reduce the wear of the valve stem on the outer lining of the spring energy storage seal ring 1c1, the surface roughness Ra of the equal-diameter section 2a is set to be less than or equal to 0.8 micrometers, and the surface roughness Ra of the remaining positions is set to 1.6 micrometers. In this embodiment, in addition, the material of the valve stem 2 is selected as a material with a hardness greater than 150 HRB, such as 1Cr13, 2Cr13, etc. In order to ensure the sealing performance of the interaction position, the tolerance of the valve stem should be designed to be H7 level when designing.

[0119] In this embodiment, the surface profile of the tapered section 2b of the valve stem 2 has been optimized to achieve the optimized matching of the flow coefficient and the flow rate level of the cryogenic fluid, so as to obtain the mapping relationship between the opening degree and the flow coefficient. Among them, when the opening degree is less than or equal to 50%, the flow coefficient is set to 0.6, and when the opening degree is greater than 50%, the flow coefficient is set to 0.8; thus, according to the liquid flow formula:

[0120]

[0121] wherein, is the liquid flow rate, is the flow coefficient of the fluid, is the opening area of ​​the cavity throat, is the fluid density, is the inlet pressure, is the saturated vapor pressure of the fluid.

[0122] In this way, the opening area of ​​the throat of the cavity can be set.

[0123] like Figure 2 As shown, according to one embodiment of the present invention, the dynamic sealing structure 1c includes: a spring energy storage sealing ring 1c1, a first position limiting support member 1c2 and a second position limiting support member 1c3; wherein, the first position limiting support member 1c2 is arranged at one end where the sealing member installation cavity is connected to the liquid accumulation cavity, and the first position limiting support member 1c2 is detachably connected to the sealing member installation cavity; in this embodiment, the first position limiting support member 1c2 and the sealing member installation cavity can be installed by threaded connection or by interference fit; wherein, it is preferably installed by threaded connection, thereby conveniently realizing accurate positioning of the installation position of the spring energy storage sealing ring 1c1.

[0124] Furthermore, the second position-limiting support 1c3 is arranged at one end of the seal installation cavity adjacent to the end cover 1b; thus, the spring energy storage seal ring 1c1 is arranged between the first position-limiting support 1c2 and the second position-limiting support 1c3, and the opposite ends of the spring energy storage seal ring 1c1 are respectively against the first position-limiting support 1c2 and the second position-limiting support 1c3. Thus, the installation position of the spring energy storage seal ring 1c1 is accurately limited.

[0125] In this embodiment, the second limit support member 1c3 and the sealing member installation cavity can be installed by threaded connection or interference fit; of course, it can also be integrated with the end cover 1b, thereby achieving the installation of the second limit support member 1c3 through the fixed installation of the end cover 1b.

[0126] In this embodiment, the spring energy storage sealing ring 1c1 includes: an outer lining and an inner lining; wherein the outer lining is a PTFE outer lining, so that it has good low temperature resistance and good self-lubricating properties, which can reduce the friction resistance of the contact surface and reduce the driving force on the valve stem 2.

[0127] In this embodiment, the inner lining is a stainless steel spring lining, which can be specifically made of 301A stainless steel; wherein the compression amount of the inner lining along the diameter direction is at least 5%, thereby ensuring that the inner lining can expand the outer lining and stick to the wall at low temperatures to form a good sealing effect.

[0128] Combination Figure 1 , Figure 3 andFigure 6 As shown, according to an embodiment of the present invention, the gas source device 4 includes: a first gas source module 41, a second gas source module 42, and a throttling module 43; in this embodiment, the first gas source module 41 and the second gas source module 42 are respectively connected to the inlet of the throttling module 43; wherein, the outlet of the throttling module 43 is communicated with the third port or the second port; in this embodiment, the outlet of the throttling module 43 is preferably communicated with the second port, thereby facilitating a reliable connection with the gas source device 4. In particular, the valve base 1 is usually fixedly installed at a corresponding position, which can make the installation of the gas source device 4 and the second port more reliable and stable, and make the operation of the present invention more reliable in a low-temperature environment. In this embodiment, the throttling module 43 can adopt an orifice plate to achieve the gas flow rate and consumption output by the gas source device 4. Further, when the gas source device 4 is communicated with the second port, the third port serves as the gas outlet. Correspondingly, an output pipeline can be arranged at the third port so that the corresponding gas can be output to a preset area to avoid affecting the entire low-temperature valve assembly.

[0129] In this embodiment, the first gas source module 41 includes: a first gas cylinder 411 and a first control valve 412; the second gas source module 42 includes: a second gas cylinder 421 and a second control valve 422; wherein, the first gas cylinder 411 is connected to the inlet of the throttling module 43 based on the first control valve 412, and the second gas cylinder 421 is connected to the inlet of the throttling module 43 based on the second control valve 422. In this embodiment, the first gas cylinder 411 stores nitrogen; the second gas cylinder 421 stores helium.

[0130] In this embodiment, the first gas source module 41 is connected to the throttling module 43 in a detachable manner. Thus, the first gas source module 41 can be flexibly removed in different application scenarios. For example, during ground tests, the first gas source module 41 can be installed to achieve the input of different gas sources, so as to achieve flexible use during the test process and reduce the consumption of the gas in the first gas source module 41. Further, during flight tests, the second gas source module 42 can be set separately or integrated with the same type of gas source on the aircraft to achieve the effect of flexible arrangement.

[0131] Combined with Figure 9 and Figure 10As shown, according to an embodiment of the present invention, the throttling module 43 includes: a first docking joint 431, a second docking joint 432, and a throttling structure 433; wherein, the throttling structure 433 includes: a truncated cone tube 433a, a clamping and fixing ring 433b coaxially arranged outside the large-diameter end of the truncated cone tube 433a, and a baffle 433c coaxially arranged inside the small-diameter end of the truncated cone tube 433a. In this embodiment, the baffle 433c is provided with a throttling hole penetrating through its body, and the axial direction of the throttling hole is parallel to the axial direction of the truncated cone tube 433a; wherein, the throttling hole can be set to one or multiple. Further, the first docking joint 431 is a hollow tube, and the inner side surface of one end of its hollow part is set as an annular conical surface matching the outer side surface of the truncated cone tube 433a for the embedding of the throttling structure 433; correspondingly, the second docking joint 432 is a hollow tube, and the end surface of the second docking joint 432 opposite to the throttling structure 433 is set as a spherical ring surface for abutting against the inner side of the truncated cone tube 433a.

[0132] In this embodiment, the first docking joint 431 and the second docking joint 432 are connected to clamp and fix the clamping and fixing ring 433b; wherein, connection threads can be provided on the outer side of the end where the first docking joint 431 and the second docking joint 432 are connected, and a movable nut can be provided at the end of the second docking joint 432. Thus, the connection between the first docking joint 431 and the second docking joint 432 is realized by screwing the nut onto the thread on the outer side of the end of the first docking joint 431; wherein, the clamping and fixing ring 433b can be clamped based on the space between the ends of the first docking joint 431 and the second docking joint 432, or an annular abutting protrusion can be provided inside the nut to realize the clamping of the clamping and fixing ring 433b between the nut and the first docking joint 431.

[0133] In this embodiment, the end of the second docking joint 432 far from the throttling structure 433 forms the inlet of the throttling module 43, and the end of the first docking joint 431 far from the throttling structure 433 forms the outlet of the throttling module 43.

[0134] In this embodiment, the upstream pressure of the throttling structure 433 is the output pressure of the first gas source module 41 or the second gas source module 42, and its downstream is connected to the atmosphere, that is, the atmospheric pressure. For example, the upstream pressure is 2.7 MPa, and the maximum allowable diameter of the throttling hole is 0.2 mm.

[0135] Figure 11 The experimental result diagram of the cryogenic valve assembly adopting the present invention is shown, wherein, Figure 11 (P1) shows the state where the outer wall of the bellows 3 is covered with frost after working for the preset time. At this time, it can be seen that frosting / icing has occurred on the outside of the bellows 3; Figure 11(P2) shows the state when the corrugated pipe 3 is compressed to the limit. It can be seen that all the corrugations can still be fully folded in the frosting / icing state. Figure 11 (P3) shows the state of the corrugated pipe 3 during stretching. It can be seen that the sheet-like frost between the corrugations can fall off in the frosting / icing state, having the effect of facilitating the detachment of frost during movement. Figure 11 (P4) shows the state of the corrugated pipe 3 when it is fully unfolded. It can be seen that each corrugation can still be fully unfolded in the frosting / icing state. Thus, it can be seen that the solution of this application can achieve the ability to operate smoothly and stably in the frosting / icing state, having a sufficient anti-icing effect.

[0136] The above content is only an example of the specific solution of the present invention. For the equipment and structures not described in detail therein, it should be understood that the existing general equipment and general methods in the art are adopted for implementation.

[0137] The above is only one solution of the present invention and is not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing, characterized in that, Comprising: A valve base (1), a valve stem (2) movably connected to the valve base (1), a bellows (3), and a gas source device (4); The valve base (1) has a hollow liquid accumulation cavity, and the liquid accumulation cavity has a radially narrowed cavity throat; A part of the valve stem (2) extends into the liquid accumulation cavity for controlling the size of the flow area in cooperation with the cavity throat, and the remaining part of the valve stem (2) is outside the valve base (1) for connecting to a driver; The bellows (3) is sleeved outside the valve stem (2) at an interval from the valve stem (2); wherein, one end of the bellows (3) is hermetically connected to the end of the valve base (1), and the other end thereof is hermetically connected to the end of the valve stem (2) outside the valve base (1); The valve base (1) is provided with a first channel (11) for communicating the inside and outside of the bellows (3); The valve stem (2) is provided with a second channel (21) for communicating the inside and outside of the bellows (3); The gas source device (4) includes: a first gas source module (41), a second gas source module (42), and a throttling module (43); The first gas source module (41) and the second gas source module (42) are respectively and switchably connected to the inlet of the throttling module (43); The outlet of the throttling module (43) is connected to the port of the first channel (11) or the second channel (21) for gas replacement of the hollow part of the bellows (3); The valve base (1) includes: a base body (1a), an end cover (1b), and a dynamic seal structure (1c); The base body (1a) is a hollow cylindrical structure; Along the axial direction of the base body (1a), the hollow part of the base body (1a) includes a seal member installation cavity and a liquid accumulation cavity connected coaxially; One end of the seal member installation cavity away from the liquid accumulation cavity forms a fifth port at one end of the base body (1a); One end of the liquid accumulation cavity away from the seal member installation cavity forms a valve outlet (1a1) at the other end of the base body (1a); The radial side wall of the base body (1a) is provided with a valve inlet (1a2) communicating with the liquid accumulation cavity; The valve inlet (1a2) is communicated with one end of the liquid accumulation cavity and the seal member installation cavity; The end cover (1b) is detachably connected to the end of the base body (1a) provided with the fifth port, and the end cover (1b) is provided with a through hole communicating with the seal member installation cavity; The dynamic seal structure (1c) is installed in the seal member installation cavity; The valve stem (2) sequentially passes through the through hole of the end cover (1b) and the dynamic seal structure (1c) to extend into the liquid accumulation cavity; The bellows (3) is sleeved outside the end cover (1b), and the bellows (3) is hermetically connected to the end cover (1b); The first channel (11) is arranged on the end cap (1b). The first channel (11) forms a first port on the end face of the end cap (1b) that communicates with the hollow part of the corrugated pipe (3), and the first channel (11) forms a second port on the radially outer side face of the end cap (1b) that communicates with the outside. And a plurality of the first ports are arranged at equal intervals along the circumference on the end face of the end cap (1b); An annular distribution cavity is arranged inside the end cap (1b) to achieve the turning flow of the air flow in the first channel (11); The annular distribution cavity forms an opening on the inner ring face of the end cap (1b); The valve stem (2) includes: an equal-diameter section (2a) and a tapered section (2b) arranged coaxially; The diameter of the tapered section (2b) gradually decreases along the direction away from the equal-diameter section (2a); Based on the telescopic movement of the tapered section (2b) cooperating with the throat of the cavity, the flow area between the tapered section (2b) and the throat of the cavity is controlled to adjust the liquid flow rate, and the liquid flow rate formula is: Wherein, is the liquid flow rate, is the flow coefficient of the fluid, and when the opening degree is less than or equal to 50%, the flow coefficient is set to 0.6, and when the opening degree is greater than 50%, the flow coefficient is set to 0.8, is the opening area of the cavity throat, is the fluid density, is the inlet pressure, is the fluid saturated vapor pressure.

2. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing according to claim 1, characterized in that The second channel (21) forms a third port on the end face of the end of the valve stem (2) away from the valve base (1) that communicates with the outside, and the second channel (21) forms a fourth port on the radially outer side face of the valve stem (2) that communicates with the hollow part of the corrugated pipe (3); The outlet of the throttling module (43) is communicated with the third port or the second port; 3. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing according to claim 2, characterized in that The throttling module (43) includes: a first docking joint (431), a second docking joint (432) and a throttling structure (433); The throttling structure (433) includes: a truncated cone (433a), a clamping and fixing ring (433b) arranged coaxially outside the large-diameter end of the truncated cone (433a), and a baffle (433c) arranged coaxially inside the small-diameter end of the truncated cone (433a); The baffle (433c) is provided with a throttling hole penetrating through its body, and the axis of the throttling hole is arranged parallel to the axis of the truncated cone (433a); The first docking joint (431) is a hollow tube, and the inner side face of one end of its hollow part is set as an annular conical surface that matches the outer side face of the truncated cone (433a) for the embedding of the throttling structure (433); The second docking joint (432) is a hollow tube, and the end face of the end of the second docking joint (432) opposite to the throttling structure (433) is set as a spherical ring surface for abutting against the inner side of the truncated cone (433a); The first docking joint (431) and the second docking joint (432) are connected to clamp and fix the clamping and fixing ring (433b); One end of the second docking joint (432) away from the throttling structure (433) forms the inlet of the throttling module (43), and one end of the first docking joint (431) away from the throttling structure (433) forms the outlet of the throttling module (43); 4. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing according to claim 3, wherein, The second channel (21) is arranged in the equal-diameter section (2a); Circumferentially along the equal-diameter section (2a), a plurality of the fourth ports are arranged at equal intervals.

5. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing according to claim 4, characterized in that, The dynamic seal structure (1c) includes: a spring energy storage sealing ring (1c1), a first limit support (1c2), and a second limit support (1c3); The first limit support (1c2) is arranged at one end where the seal installation cavity is connected to the liquid accumulation cavity, and the first limit support (1c2) is detachably connected to the seal installation cavity; The second limit support (1c3) is arranged at one end of the seal installation cavity adjacent to the end cover (1b); The spring energy storage sealing ring (1c1) is arranged between the first limit support (1c2) and the second limit support (1c3), and opposite ends of the spring energy storage sealing ring (1c1) are respectively abutted against the first limit support (1c2) and the second limit support (1c3).

6. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing according to claim 5, characterized in that, The spring energy storage sealing ring (1c1) includes: an outer lining and an inner lining; The outer lining is a PTFE outer lining; The inner lining is a stainless steel spring inner lining, and the compression amount of the inner lining in the diameter direction is at least 5%.

7. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing according to claim 6, characterized in that, The end cover (1b) is a heat-insulating non-metallic material cover, and the surface roughness Ra of the end cover (1b) is less than 1.6 microns; The valve stem (2) is a stainless steel metal rod, wherein the surface roughness Ra of the equal-diameter section (2a) of the valve stem (2) is less than or equal to 0.8 microns; The hardness of the valve stem (2) is greater than 150 HRB; The bellows (3) is a PTFE material bellows; The bellows (3) satisfies: Among them, is the length of the hollow cavity of the corrugated pipe (3), is the wall thickness of the corrugated pipe (3), is the corrugation depth of the corrugated pipe (3), is the minimum length of compression of the corrugated pipe (3), is the maximum length of stretching of the corrugated pipe (3), is the number of waves of the corrugated pipe (3); The first gas source module (41) includes: a first gas cylinder (411) and a first control valve (412); The second gas source module (42) includes: a second gas cylinder (421) and a second control valve (422); The first gas cylinder (411) is connected to the inlet of the throttling module (43) based on the first control valve (412), and the second gas cylinder (421) is connected to the inlet of the throttling module (43) based on the second control valve (422); The first gas cylinder (411) stores nitrogen; The second gas cylinder (421) stores helium; If the outlet of the throttling module (43) is connected to the port of the first channel (11), then the inner diameter of the first channel (11) is greater than the aperture of the throttling hole, and the inner diameter of the second channel (21) is greater than the inner diameter of the first channel (11), and the opening diameter of the fourth port is less than the inner diameter of the first channel (11); If the outlet of the throttling module (43) is connected to the port of the second channel (21), then the inner diameter of the second channel (21) is greater than the aperture of the throttling hole, and the inner diameter of the first channel (11) is greater than the inner diameter of the second channel (21), and the opening diameter of the first port is less than the inner diameter of the second channel (21).

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