Low-temperature valve assembly with integrated valve rod anti-icing and de-icing and dynamic sealing functions

Abstract

The invention relates to a low-temperature valve assembly with integrated valve rod ice preventing and removing and dynamic sealing functions. The low-temperature valve assembly comprises a valve base, a valve rod, a corrugated pipe and an air source device. The valve base is provided with a liquid accumulation cavity, and the liquid accumulation cavity is provided with a cavity throat part which is shrunk in the radial direction. The valve rod partially extends into the liquid accumulation cavity and is used for being matched with the throat part of the cavity to control the size of the flow area, and the rest part of the valve rod is located outside the valve base; one end of the corrugated pipe is connected with the end part of the valve base, and the other end is connected with the end part of the valve rod; the valve base is provided with a first channel for communicating the inside and the outside of the corrugated pipe; the valve rod is provided with a second channel for communicating the inside and the outside of the corrugated pipe; the air source device comprises a first air source module, a second air source module and a throttling module. The first gas source module and the second gas source module are respectively connected with an inlet of the throttling module in a switchable manner; and an outlet of the throttling module is connected with a port of the first channel or the second channel so as to carry out gas replacement on the hollow part of the corrugated pipe.

Description

Technical Field

[0001] The present invention relates to the field of aerospace technology, and in particular to a cryogenic valve assembly with integrated valve stem deicing protection and dynamic sealing. Background Art

[0002] During the ground test or actual flight of the cryogenic variable thrust engine, it is necessary to undergo a long period of cryogenic medium precooling to cool the pipeline from the tank to the engine to below the saturation temperature of the medium. Generally, liquid oxygen is -170℃, methane is -150℃, and the simulated medium liquid nitrogen is -190℃. The precooling time is about 1~2 hours or even longer. Long-term low-temperature precooling 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. Low-temperature stagnation will affect the propellant flow entering the engine on the one hand, and even cause the valve to fail to open or close normally according to the timing on the other hand, causing accidents of engine damage; in addition, ice on the valve stem surface will also enter the valve during the movement of the valve stem, causing the dynamic sealing structure in the valve to be destroyed, which will lead to serious consequences of propellant leakage.

[0003] In current aircraft or ground tests, there are two main solutions for anti-icing: the first is a preventive approach, which uses hydrophobic coatings, special waterproof materials, surface micro-nano structures, vacuum sealing environments, etc. for pre-prevention; the second is post-icing after ice formation, which uses external methods such as electric heating, large-flow gas blowing, mechanical deicing, and thermal deicing as deicing methods.

[0004] For the real cryogenic engine supply system, its working environment is harsh. The valve is in an extremely low temperature and long-term cooling condition. The humidity of the air in the environment where the valve stem surface is located is high, which is very easy to cause severe icing. Therefore, the cryogenic valve is usually large in size and mass, and has a stuffing box of sufficient length to reduce the heat conduction of the valve stem. In the first scheme, since the valve stem is a movable surface, it is difficult to create a vacuum environment to isolate water vapor, and the use of coatings and microstructures will cause wear on the sealing surface; in the second scheme, the valve is filled with a large flow of cryogenic propellant fuel / oxidizer. Once it leaks and the ignition source is added, it will cause an explosion. Electric heating deicing and other methods will introduce potential sources of danger; in the case of severe icing, relying solely on gas for deicing will consume a lot of gas, and it is impossible to carry a large amount of deicing gas under the payload constraints of the real aircraft. In addition, in the electric heating scheme, it is necessary to carry an additional power supply, 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, the cryogenic valve has problems such as large size, heavy mass, complex deicing method, and high gas consumption, which makes it difficult to meet the miniaturization and integration requirements of the cryogenic system. In addition, some solutions require additional power supply and regular maintenance, which cannot meet the constraints of ground tests and real aircraft. Moreover, these solutions greatly increase the launch dead weight and launch cost of related vehicles, and are 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, so as to solve the problem of low-temperature icing and frost on the valve stem caused by real cryogenic propellant.

[0007] To achieve the above-mentioned purpose, the present invention provides a cryogenic valve assembly with integrated valve stem anti-icing and dynamic sealing, comprising: a valve base, a valve stem movably connected to the valve base, a bellows and an air source device; The valve base has a hollow liquid accumulation cavity, and the liquid accumulation cavity has a radially reduced cavity throat; The valve stem partially extends into the liquid accumulation cavity to cooperate with the throat of the cavity to control the size of the flow area, and the remaining portion of the valve stem is located outside the valve base to be connected to the driver; The bellows is sleeved outside the valve stem with a gap between it and the valve stem; 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; 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 passage for communicating the inside and outside of the bellows; The gas source device comprises: 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 switchably connected to the inlet of the throttling module respectively; The outlet of the throttling module is connected to a port of the first channel or the second channel so as to replace gas in the hollow portion of the bellows.

[0008] According to one aspect of the present invention, the first channel is arranged at one end of the valve base connected to the bellows; wherein the first channel forms a first port connected to the hollow portion of the bellows on an end surface of the end of the valve base, and the first channel forms a second port connected to the outside on a radially outer surface of the end of the valve base; The second channel forms a third port communicating with the outside on the end surface of the valve stem away from the valve base, and the second channel forms a fourth port communicating with the hollow portion of the bellows on the radially outer side surface of the valve stem; The outlet of the throttling module is communicated with the third port or the second port.

[0009] According to one aspect of the present invention, the throttling module comprises: a first butt joint, a second butt joint and a throttling structure; The throttling structure comprises: a truncated cone, a clamping and fixing ring coaxially arranged outside the large diameter end of the truncated cone, and a baffle coaxially arranged inside the small diameter end of the truncated cone; The baffle is provided with a throttle hole penetrating its body, and the throttle hole is arranged axially parallel to the axial direction of the truncated cone cylinder; The first butt joint is in the shape of a hollow tube, and the inner side surface of one end of the hollow portion is configured as an annular cone surface matching the outer side surface of the truncated cone tube, so as to allow the throttling structure to be embedded; The second butt joint is in the shape of a hollow tube, and the end surface of the second butt joint opposite to the throttling structure is configured as a spherical ring surface for abutting against the inner side of the truncated cone; The first butt joint and the second butt joint are connected to clamp and fix the clamping and fixing ring; One end of the second butt joint away from the throttling structure forms an inlet of the throttling module, and one end of the first butt joint away from the throttling structure forms an outlet of the throttling module.

[0010] According to one aspect of the present invention, the mass flow rate of the throttling hole of the throttling structure satisfies: .

[0011] in, is the mass flow rate of gas; is the flow coefficient of the orifice; is the cross-sectional area of ​​the throttle hole, and , is the diameter of the throttle hole; is the pressure difference between upstream and downstream of the throttling structure; is the pressure downstream of the orifice plate and is a constant; is the gas constant; is the gas temperature; is the specific heat ratio of gases; is the universal gas constant; is the critical pressure ratio.

[0012] According to one aspect of the present invention, the valve base comprises: a base body, an end cover and a dynamic sealing structure; The base body is a hollow cylindrical structure; Along the axial direction of the base body, the hollow portion of the base body includes a seal installation cavity and a liquid accumulation cavity which are coaxially connected; An end of the sealing member installation cavity away from the liquid accumulation cavity forms a fifth port at one end of the base body; One end of the liquid accumulation cavity away from the sealing element installation cavity forms a valve outlet at the other end of the base body; The radial side wall of the base body is provided with a valve inlet communicating with the liquid accumulation cavity; The valve inlet is in communication with one end of the liquid accumulation chamber and the sealing element installation chamber; The end cover is detachably connected to one end of the base body provided with the fifth port, and the end cover is provided with a through hole communicating with the sealing member installation cavity; The dynamic sealing structure is installed in the sealing element installation cavity; The valve stem passes through the through hole of the end cover and the dynamic sealing structure in sequence to extend into the liquid accumulation cavity.

[0013] According to one aspect of the present invention, the bellows is sleeved on the outside of the end cover, and the bellows is sealed and connected to the end cover; The first channel is arranged on the end cover, and a plurality of the first ports are arranged at equal intervals along a ring shape on the end surface of the end cover; The second port is disposed on the radially outer side of the end cover.

[0014] According to one aspect of the present invention, the valve stem comprises: a coaxially arranged equal diameter section and a tapered section; The diameter of the tapered section is gradually reduced in a direction away from the equal diameter section; The second channel is arranged in the equal diameter section; A plurality of fourth ports are arranged at equal intervals along the circumference of the equal-diameter segment.

[0015] According to one aspect of the present invention, the dynamic sealing structure comprises: a spring energy storage sealing ring, a first position limiting support member and a second position limiting support member; The first limiting support member is disposed at one end of the sealing member installation cavity connected to the liquid accumulation cavity, and the first limiting support member is detachably connected to the sealing member installation cavity; The second position-limiting support is arranged at one end of the sealing member installation cavity adjacent to the end cover; The spring energy storage sealing ring is arranged between the first position limiting support member and the second position limiting support member, and opposite ends of the spring energy storage sealing ring are respectively against the first position limiting support member and the second position limiting support member.

[0016] According to one aspect of the present invention, the spring energy storage seal ring comprises: an outer liner and an inner liner; The outer lining is a PTFE outer lining; The liner is a stainless steel spring liner, and the compression amount of the liner along the diameter direction is at least 5%.

[0017] According to one aspect of the present invention, the end cap is a heat-insulating non-metallic material cap, and the surface roughness Ra of the end cap is less than 1.6 microns; The valve stem is a stainless steel metal stem, wherein the surface roughness Ra of the equal diameter section of the valve stem is less than or equal to 0.8 micrometers; The hardness of the valve stem is greater than 150HRB; The bellows is made of PTFE material; The bellows meets the following requirements: .

[0018] in, 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 bellows when compressed, is the maximum length of the bellows stretched, is the wave number of the bellows; The first gas source module comprises: a first gas cylinder and a first control valve; The second gas source module comprises: a second gas cylinder and a second control valve; 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; The first gas cylinder stores nitrogen; The second gas cylinder stores helium; If the outlet of the throttling module is connected to the port of the first channel, the inner diameter of the first channel is larger than the aperture of the throttling hole, and the inner diameter of the second channel is larger than the inner diameter of the first channel, and the opening diameter of the fourth port is smaller than the inner diameter of the first channel; If the outlet of the throttling module is connected to the port of the second channel, the inner diameter of the second channel is larger than the aperture of the throttling hole, and the inner diameter of the first channel is larger than the inner diameter of the second channel, and the opening diameter of the first port is smaller than the inner diameter of the second channel.

[0019] According to a scheme of the present invention, the system adopts gas dilution and replacement to prevent deicing and realize directional discharge of leakage. Compared with traditional post-deicing and equipment, electric deicing and other methods, the system integration of this scheme is high, the system scheme complexity is low, and the implementation method is reliable. The use of pre-prevention methods can effectively avoid the damage to the valve stem surface and sealing components caused by post-deicing, and can also eliminate the dangerous sources introduced by electric deicing and other methods.

[0020] According to a solution of the present invention, this solution can use two different gas sources according to different mission scenarios to save test costs and launch costs. In view of the specific circumstances 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 tests and aircraft precooling stages, and the helium carried by the aircraft is used during actual flight on the aircraft. After the aircraft leaves the atmosphere and reaches a vacuum environment, no dilution gas is required. Therefore, the advantage of this setting is that, since nitrogen is cheaper than helium, and the amount of helium carried by the aircraft is not enough to cover the entire precooling process, this method saves economic costs on the one hand, and on the other hand, it can also reduce the dead weight of helium carried by the aircraft and reduce launch costs.

[0021] According to one solution of the present invention, a variable volume sealing environment is constructed by combining a valve stem, a bellows and an end cap. In both static and dynamic operation of the valve, an environment of diluted gas components can be created to displace water vapor, thereby avoiding ice formation. According to the characteristics of the reciprocating motion 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 cap, which ensures reliable sealing and realizes the creation of a closed space.

[0022] According to one solution of the present invention, this solution reduces the existence of drainage pipelines and reduces the risk of leakage at the interface position by forming a gas flow channel inside the structure. Among them, the dilution gas inlet is preferably connected to the flow channel port on the radial outer side of the end cover, and flows out through the axial flow channel port of the end cover. The gas flowing out of the end cover can directly blow off the surface of the valve stem to take away moisture and excess. Finally, the dilution gas in the enclosed space of the bellows flows out through the radial and axial flow channel structure inside the valve stem, realizing the directional discharge and treatment of moisture, excess, and leakage.

[0023] According to one solution of the present invention, a low-temperature medium dynamic sealing method is adopted in this solution, which is composed of an end cover, a valve stem, a spring energy storage seal ring and a base body. The wear of the energy storage seal ring is reduced by a valve stem with high hardness and low surface roughness, and sufficient compression of the spring energy storage seal ring is ensured by axial compression; in the radial direction, the spring energy storage ring can compensate for the deformation of the material at low temperature, ensuring that the low-temperature propellant will not leak along the axial gap.

[0024] According to a solution of the present invention, the solution adopts a non-metallic end cover including an inner flow channel, which can effectively reduce the heat conduction of the valve seat along a one-dimensional direction and effectively improve the temperature environment inside the bellows.

[0025] According to one solution of the present invention, the end cover is provided with a plurality of ports along the ring on the end surface so as to realize uniform blowing of the outer surface of the valve stem in the circumferential direction, thereby effectively ensuring the blowing effect of the gas on the valve stem surface.

[0026] According to one scheme of the present invention, the present invention can realize the effective anti-icing of the valve stem of the low-temperature flow regulating valve. It is based on the idea of ​​prior de-icing to reduce the de-icing cost and reduce the harm of ice and jamming of the flow regulating valve; the method of switching between nitrogen / helium gases can effectively reduce the launch dead weight and improve the economy of de-icing; by adding a throttling orifice plate, the gas consumption can be controlled.

[0027] According to one solution of the present invention, the system uses a polytetrafluoroethylene bellows with good low temperature resistance, compression and tensile properties as a solution for waterproofing, dustproofing, preventing excess objects and constructing a closed space, which can improve the low temperature reliability of the device. At the same time, the low temperature working life of the device can be extended by regularly replacing and maintaining the bellows.

[0028] According to one solution of the present invention, a spring energy storage seal ring is used as a dynamic seal mechanism for the operation of the valve stem to drain and dilute the possible trace leakage of propellant to achieve the purpose of directional discharge. The combination of dynamic seal and directional discharge can prevent the propellant from accumulating around the device after leakage, thereby improving the safety and reliability of the device.

[0029] According to one solution of the present invention, the present invention realizes the anti-icing and dynamic sealing performance of the valve stem of the flow control valve to achieve reliable operation at low temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a structural diagram of a cryogenic valve assembly according to an embodiment of the present invention; Figure 2 A structural diagram of a dynamic sealing structure according to an embodiment of the present invention; Figure 3It is a structural diagram of the throat of the cavity where the valve stem of the cryogenic valve assembly in one embodiment of the present invention extends into the liquid accumulation cavity; Figure 4 A structural diagram of a bellows according to an embodiment of the present invention; Figure 5 A structural diagram of a valve stem according to an embodiment of the present invention; Figure 6 A connection structure diagram of a cryogenic valve assembly according to an embodiment of the present invention; Figure 7 A structural diagram of an end cover according to an embodiment of the present invention; Figure 8 is a cross-sectional view of an end cap according to an embodiment of the present invention; Fig. 9 A structural diagram of a throttling module according to an embodiment of the present invention; Fig.10 A cross-sectional view of a throttling structure according to an embodiment of the present invention; Fig.11 The number of throttling holes of the throttling structure of one embodiment of the present invention is x The changing pattern of gas flow rate, mass flow rate and volume flow rate during the changing process, among which, Fig.11 (a) indicates the number of throttle holes x The variation law of gas flow rate, Fig.11 (b) indicates the number of throttle holes x The variation law of gas mass flow rate, Fig.11 (c) indicates the number of throttle holes x The variation law of gas volume flow rate; Fig.12 This is a diagram showing the tensile and compression test results of a cryogenic valve assembly under low temperature conditions according to an embodiment of the present invention, wherein: Fig.12 (P1) represents the state diagram of the outer wall of the bellows covered with frost after working for a preset time. Fig.12 (P2) represents the state diagram when the bellows is compressed to the limit. Fig.12 (P3) represents the state diagram of the bellows when stretched. Fig.12 (P4) is a diagram showing the state of the bellows when it is fully expanded. DETAILED DESCRIPTION

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] When describing the embodiments of the present invention, the orientation or positional relationship expressed by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or positional relationship shown in the relevant drawings and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0033] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments cannot be described one by one here, but the embodiments of the present invention are not therefore limited to the following embodiments.

[0034] Combination 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 an air 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, and the bellows 3 and the air 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 radially reduced cavity throat; wherein the valve stem 2 partially extends into the liquid accumulation cavity, and is used to control the size of the flow area in coordination with the cavity throat, and the rest of the valve stem 2 is outside the valve base 1, and is used to connect with the driver; in this embodiment, the valve stem 2 can be based on an automatically controlled driver to achieve its relative position to the cavity throat in the liquid accumulation cavity, thereby achieving the area change of the annular interval between the valve stem 2 and the cavity throat to achieve the flow control effect of the fluid.

[0035] In the present embodiment, the bellows 3 and the valve stem 2 are sleeved on the outside of the valve stem 2 with an interval; wherein, one end of the bellows 3 is sealedly connected to the end of the valve base 1, and the other end thereof is sealedly connected to the end of the valve stem 2 outside the valve base 1; in the present embodiment, the radial dimension of the bellows 3 is larger than the radial dimension of the valve stem 2, thereby, a hollow space can be formed between the bellows 3 and the valve stem 2 to facilitate the storage of 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 ice / frost phenomenon 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.

[0036] In this embodiment, an annular protrusion is provided at the position connected to the bellows 3 on the valve stem 2, so that the bellows 3 can be sleeved on the annular protrusion to achieve a corresponding sealed connection; wherein, in order to ensure the sealing of the connection between the valve stem 2 and the annular protrusion, the annular protrusion can be fixed to the valve stem 2 by welding, interference fit connection, threaded connection, clamping, etc. Through the above arrangement, the bellows 3 can conveniently seal and cover the part of the valve stem 2 exposed to the outside, so as to fully achieve the sealing of the active stroke of the valve stem 2, so that after the air containing water vapor inside is removed, the effect of preventing ice / frost can be fully achieved.

[0037] In this embodiment, the annular protrusion on the valve stem 2 for connecting with 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, thereby, the end of the bellows 3 can be sleeved on the small diameter end of the annular protrusion, and a sealing connection can be used to achieve a corresponding fixing effect.

[0038] Furthermore, the valve base 1 is provided with a first channel 11 for connecting the inside and outside of the bellows 3; the valve stem 2 is provided with a second channel 21 for connecting the inside and outside of the bellows 3; wherein the air source device 4 is connected to the port of the first channel 11 or the second channel 21, so as to replace the gas in the hollow part of the bellows 3. Thus, the air source device 4 can realize the input of replacement gas from the port of one of the channels through the port of the first channel 11 or the second channel 21, and correspondingly discharge the air in the bellows 3 from the other channel, thereby fully eliminating the water that may freeze therein to achieve the effect of anti-deicing.

[0039] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As 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.

[0040] 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 .

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] In this embodiment, the dynamic sealing structure 1c is installed in the sealing member installation cavity, whereby the valve stem 2 sequentially passes through the through hole of the end cover 1b and the dynamic sealing structure 1c to extend into the liquid accumulation cavity. The dynamic sealing structure 1c can achieve contact sealing with the valve stem 2 in the radial direction, so that when the position of the valve stem 2 changes, the dynamic sealing structure 1c can produce corresponding shape changes with different positions of the valve stem 2 to achieve dynamic sealing at the contact position.

[0049] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 7 and Figure 8As shown, the end cap 1b is preferably made of non-metallic material, for example, it is made of non-metallic PTFE material with poor thermal conductivity. On the one hand, the material has poor thermal conductivity, which can block the heat conduction of low-temperature fluid and improve the local thermal environment; on the other hand, due to its excellent processing performance similar to metal, it can be turned, and has good surface roughness after turning. At the same time, it can adapt to the low temperature environment of -200°C, and its linear expansion coefficient is about 1.2~1.5μm / °C. In this embodiment, the surface roughness Ra of the end cap 1b is less than 1.6 microns to effectively ensure the smoothness of the overall outer surface, which is beneficial to ensuring the structural airtightness of the installation position.

[0050] In this embodiment, a plurality of through holes for threaded connectors to pass through may be provided on the end cover 1b along the circumference of the end cover 1b, thereby conveniently fixing the end cover 1b on the base body 1a.

[0051] In this embodiment, the first channel 11 is provided on the end cover 1b, and a plurality of first ports are provided at equal intervals along a ring on the end surface of the end cover 1b; the second port is provided on the radial outer surface of the end cover 1b. In this embodiment, the second port can be provided in plurality, and the first port can be provided in one-to-one correspondence with the second port, thereby achieving unified connection by providing a plurality of joints. Of course, the second port can also be provided in one, so as to achieve a unified distribution / collection effect of gas between the second port and the plurality of first ports by providing a unified connection between the second port and the plurality of second ports.

[0052] Combination Figure 7 and Figure 8 As shown, preferably, the first channel 11 is set to one, and the first ports on the end surface are set to 8, wherein the second port is formed based on a channel perpendicular to the axial direction of the first channel 11, and its diameter is 1mm, so as to achieve communication with the first channel 11. In this embodiment, the setting position of the first channel 11 needs to avoid the through hole on the end cover 1b for the threaded connector to pass through, so as to avoid air leakage. Moreover, the axial direction of the first channel 11 is set perpendicular to the axial direction of the end cover 1b to facilitate the processing and molding of the first channel 11.

[0053] Furthermore, in order to connect the second port with the first channel 11, an annular distribution cavity for connecting the second port with the first channel 11 is also provided inside the end cover 1b, thereby achieving uniform distribution of the gas.

[0054] Furthermore, the annular distribution cavity provided in the end cover 1b can form an opening on the inner annular surface of the end cover 1b, thereby, the annular distribution cavity can be blocked based on the valve stem 2 passing through the end cover 1b, so as to achieve the redirected flow of the gas flow between the first channel 11 and the second port. Through the above-mentioned arrangement, the annular distribution cavity is formed into an opening on the inner annular surface of the end cover 1b, which can conveniently realize the processing and forming of the annular distribution cavity on the one hand, and on the other hand, can also make the gas directly surround the outer side of the valve stem 2, so that the position that the bellows 3 cannot accommodate can still have a certain protective atmosphere, thereby preventing and promoting the anti-deicing between the valve stem 2 and the end cover 1b, and thus more beneficial to ensure the stable and reliable operation of the valve stem 2.

[0055] 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 input end of the gas, the inner diameter of the first channel 11 is larger than the aperture of the throttling hole set in the throttling module 43, thereby preventing gas congestion in the channel. 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, and the diameter of the annealed copper tube can be larger than the diameter of the orifice plate (for example, the inner diameter of the annealed copper tube is 2 mm in outer diameter, 0.5 mm in wall thickness, and its flow cross section is Φ1 mm). Through the above arrangement, the connection method using the annealed copper tube can effectively avoid rupture during the bending process, ensuring the reliability of the structure.

[0056] Combination Figure 1 , Figure 3 and Figure 4 As shown, according to one embodiment of the present invention, the bellows 3 is sleeved on the outside of the end cap 1b, and the bellows 3 and the end cap 1b are sealed and connected; wherein, in order to achieve reliable cooperation with the end cap 1b and to avoid the copper tube connected to the second port, a U-shaped opening can be provided at the end of the bellows 3, thereby avoiding interference with the copper tube, and the remaining positions can be installed on the outside of the end cap 1b in a sealed and fixed manner. In this embodiment, the end of the bellows 3 is installed on the outside of the end cap 1b in a transitional fit manner; wherein, the sealed and fixed manner can be achieved by a combination of fastening with a cable tie and filling with a low-temperature weather-resistant adhesive.

[0057] In this embodiment, the bellows 3 is a PTFE bellows to ensure its low temperature resistance. Further, to ensure that the bellows 3 fully meets the control stroke of the entire cryogenic valve assembly, the bellows 3 meets: .

[0058] in, is the length of the hollow cavity of the bellows 3, is the wall thickness of the bellows 3, is the corrugation depth of the bellows 3, is the minimum length of bellows 3 when compressed, is the maximum length of the bellows 3 stretched, is the wave number of bellows 3.

[0059] Therefore, the bellows 3 can achieve a compressed length less than or equal to the minimum allowable length, and a stretched length greater than or equal to the maximum allowable length.

[0060] Combination Figure 1 , Figure 3 and Figure 5 As shown, according to one embodiment of the present invention, the valve stem 2 includes: a coaxially arranged equal diameter section 2a and a tapered section 2b; wherein the diameter of the tapered section 2b is gradually reduced in the direction away from the equal diameter section 2a; the tapered section 2b is arranged to cooperate with the cavity throat in the effusion cavity, wherein, based on the radially variable tapered section 2b, as the length of the tapered section 2b extending into the cavity throat changes, the annular flow area between the tapered section 2b and the cavity throat can be flexibly adjusted.

[0061] In this embodiment, the second channel 21 is arranged in the equal diameter section 2a; wherein the second channel 21 has an intermediate channel collection part and a peripheral channel dispersion part; wherein the intermediate channel collection part is arranged coaxially with the equal diameter section 2a, and a third port is formed at the end of the equal diameter section 2a, and the peripheral channel dispersion part is arranged to extend along the radial direction of the equal diameter section 2a, thereby, one end of the peripheral channel dispersion part is connected to the intermediate channel collection part, and the other end forms a fourth port on the outer surface of the equal diameter section 2a, wherein a plurality of peripheral channel dispersion parts are arranged, 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 mentioned above, it is preferred that 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 larger than the aperture of the throttling hole, and the inner diameter of the intermediate channel collection part of the second channel 21 is larger than the inner diameter of the first channel 11, the opening diameter of the fourth port is smaller than the inner diameter of the first channel 11, thereby ensuring the smoothness of the airflow from the input to the output direction to fully eliminate the congestion of the airflow. Of course, in another embodiment, if the outlet of the throttling module 43 is connected to the port of the second channel 21, the inner diameter of the second channel 21 is larger than the aperture of the throttling hole, and the inner diameter of the first channel 11 is larger than the inner diameter of the second channel 21, and the opening diameter of the first port is smaller than the inner diameter of the second channel 21, so that when the gas is transported in the reverse direction, the beneficial effect of eliminating the congestion of the gas flow is also achieved. In short, it is sufficient to meet the effect that the sum of the volume of the upstream gas plus the volume of the sealed micro-leakage gas is less than the maximum allowable gas output of the downstream.

[0062] Furthermore, the valve stem 2 can be set as a stainless steel metal stem. In order to ensure service life and 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 microns, and the surface roughness Ra of the remaining positions is set to 1.6 microns. In this embodiment, in addition, the material of the valve stem 2 is selected from a material with a hardness greater than 150HRB, such as 1Cr13, 2Cr13, etc. In order to ensure the sealing of the interactive position, the tolerance of the valve stem should be guaranteed to be H7 during design.

[0063] In this embodiment, the surface profile of the tapered section 2b of the valve stem 2 is optimized to achieve a flow coefficient of low temperature fluid. The mapping relationship between the opening and the flow coefficient is obtained by optimizing the flow level. When the opening is less than or equal to 50%, the flow coefficient Set to 0.6, when the opening is greater than 50%, the flow coefficient is set to 0.8; therefore, according to the liquid flow formula: .

[0064] in, 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.

[0065] In this way, the opening area of ​​the throat of the cavity can be set.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] Combination Figure 1 , Figure 3 and Figure 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 connected to the third port or the second port; in this embodiment, the outlet of the throttling module 43 is preferably connected to the second port, thereby facilitating reliable connection with the gas source device 4, in particular, the valve base 1 is usually fixedly installed at the 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 in a low temperature environment more reliable. In this embodiment, the throttling module 43 can adopt a throttling orifice plate to realize the gas flow and consumption output by the gas source device 4. Further, when the gas source device 4 is connected to the second port, the third port is used as the outlet of the gas, and accordingly, an output pipeline can be set at the third port so that the corresponding gas is output to a preset area to avoid affecting the entire low temperature valve assembly.

[0072] 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; and the second gas cylinder 421 stores helium.

[0073] In this embodiment, the first gas source module 41 is connected to the throttling module 43 in a detachable manner, so that the first gas source module 41 can be flexibly removed in different application scenarios. For example, during ground testing, the first gas source module 41 can be installed to input different gas sources, thereby achieving flexible use during the test process to reduce the consumption of gas in the first gas source module 41. Furthermore, during flight testing, 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.

[0074] Combination Fig. 9 and Fig.10 As shown, according to one embodiment of the present invention, the throttling module 43 includes: a first butt joint 431, a second butt joint 432 and a throttling structure 433; wherein the throttling structure 433 includes: a truncated cone 433a, a clamping and fixing ring 433b coaxially arranged outside the large diameter end of the truncated cone 433a, and a baffle 433c coaxially arranged inside the small diameter end of the truncated cone 433a. In this embodiment, the baffle 433c is provided with a throttling hole penetrating its body, and the throttling hole is axially arranged parallel to the axial direction of the truncated cone 433a; wherein the throttling hole can be set to one or more. Furthermore, the first docking joint 431 is hollow tubular, and the inner side surface of one end of the hollow portion is set as an annular cone surface matching the outer side surface of the truncated cone cylinder 433a, so as to allow the throttling structure 433 to be embedded; correspondingly, the second docking joint 432 is hollow tubular, and the end surface of the second docking joint 432 at one end opposite to the throttling structure 433 is set as a spherical annular surface, so as to abut against the inner side of the truncated cone cylinder 433a.

[0075] In this embodiment, the first docking joint 431 and the second docking joint 432 are connected to each other for clamping and fixing the clamping and fixing ring 433b; wherein, a connecting thread can be provided on the outer side of one 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, thereby, the connection between the first docking joint 431 and the second docking joint 432 is realized by screwing the nut on the threaded structure on the outer side of the end of the first docking joint 431; wherein, the clamping and fixing ring 433b can be clamped between the ends of the first docking joint 431 and the second docking joint 432, and an annular abutment protrusion can be provided on the inner side of the nut to realize the clamping and fixing ring 433b between the nut and the first docking joint 431.

[0076] In this embodiment, one end of the second docking joint 432 away from the throttling structure 433 forms an inlet of the throttling module 43 , and one end of the first docking joint 431 away from the throttling structure 433 forms an outlet of the throttling module 43 .

[0077] According to one embodiment of the present invention, the mass flow rate of the throttling hole of the throttling structure 433 satisfies: .

[0078] in, is the mass flow rate of gas; is the flow coefficient of the orifice; is the cross-sectional area of ​​the throttle hole, and , is the diameter of the throttle hole; is the pressure difference between upstream and downstream of the throttling structure 433; is the pressure downstream of the orifice plate and is a constant; is the gas constant; is the gas temperature; is the specific heat ratio of gases; is the universal gas constant; is the critical pressure ratio.

[0079] 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 the downstream thereof is connected to the atmosphere, that is, the atmospheric pressure. For example, the upstream pressure is 2.7 MPa, the maximum allowable throttling hole diameter is 0.2 mm, and the gas volume flow rate (i.e., mass flow rate) is Specific density ) is about 6ml / s, the gas flow rate at the throttle position Up to 310m / s, the corresponding number of holes x During the change process, the changing rules of gas flow rate, mass flow rate and volume flow rate are as follows: Fig.11 shown.

[0080] Fig.12 The experimental results of the cryogenic valve assembly of the present invention are shown in FIG. Fig.12 (P1) shows the state where the outer wall of the bellows 3 is covered with frost after the preset working time. At this time, it can be seen that frost / ice has formed on the outer side of the bellows 3; Fig.12 (P2) shows the state of the bellows 3 when it is compressed to the limit, and it can be seen that all the corrugations can still be fully folded in the frosted / iced state; Fig.12 (P3) shows the state of the bellows 3 when stretched, showing that the flakes of frost between the corrugations can fall off in the frosted / iced state, which facilitates the frost to be detached during movement; Fig.12 (P4) shows the state of the bellows 3 when it is fully expanded, and it can be seen that the bellows can still be fully expanded in the frosted / iced state. It can be seen that the present application scheme can achieve the ability to operate smoothly and stably in the frosted / iced state, and has a sufficient anti-icing effect.

[0081] The above contents are merely examples of specific solutions of the present invention. For devices and structures not described in detail therein, it should be understood that they can be implemented by adopting general devices and general methods available in the art.

[0082] The above is only one solution of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. 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 deicing protection and dynamic seal, characterized in that: include: A valve base (1), a valve stem (2) movably connected to the valve base (1), a bellows (3) and an air source device (4); The valve base (1) has a hollow liquid accumulation cavity, and the liquid accumulation cavity has a cavity throat that decreases radially; The valve stem (2) partially extends into the liquid accumulation cavity and is used to cooperate with the throat of the cavity to control the size of the flow area, and the remaining part of the valve stem (2) is located outside the valve base (1) and is used to be connected to the driver; The bellows (3) and the valve stem (2) are sleeved outside the valve stem (2) with a spacing therebetween; wherein one end of the bellows (3) is sealedly connected to the end of the valve base (1), and the other end is sealedly 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 connecting the inside and the outside of the bellows (3); The valve stem (2) is provided with a second channel (21) for communicating the inside and the outside of the bellows (3); The gas source device (4) comprises: 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 switchably connected to the inlet of the throttling module (43) respectively; The outlet of the throttling module (43) is connected to a port of the first channel (11) or the second channel (21) so as to replace gas in the hollow portion of the bellows (3).

2. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic seal according to claim 1, characterized in that: 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 on the end surface of the end of the valve base (1) and communicates with the hollow portion of the bellows (3); and the first channel (11) forms a second port on the radially outer surface of the end of the valve base (1) and communicates with the outside; The second channel (21) forms a third port connected to the outside on an end surface of the valve stem (2) away from the valve base (1), and the second channel (21) forms a fourth port connected to the hollow portion of the bellows (3) on a radially outer surface of the valve stem (2); The outlet of the throttling module (43) is connected to the third port or the second port.

3. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic seal according to claim 2, characterized in that: The throttling module (43) comprises: a first butt joint (431), a second butt joint (432) and a throttling structure (433); The throttling structure (433) comprises: a truncated cone cylinder (433a), a clamping and fixing ring (433b) coaxially arranged outside the large diameter end of the truncated cone cylinder (433a), and a baffle (433c) coaxially arranged inside the small diameter end of the truncated cone cylinder (433a); The baffle (433c) is provided with a throttle hole penetrating its body, and the throttle hole is axially arranged parallel to the axial direction of the truncated cone cylinder (433a); The first butt joint (431) is in the shape of a hollow tube, and the inner side surface of one end of the hollow portion is arranged as an annular cone surface matching the outer side surface of the truncated cone cylinder (433a) so as to allow the throttling structure (433) to be embedded; The second butt joint (432) is in the shape of a hollow tube, and the end surface of the second butt joint (432) opposite to the throttling structure (433) is arranged as a spherical annular surface, so as to abut against the inner side of the truncated cone cylinder (433a); The first butt joint (431) and the second butt joint (432) are connected to each other so as to clamp and fix the clamping and fixing ring (433b); An end of the second butt joint (432) away from the throttling structure (433) forms an inlet of the throttling module (43), and an end of the first butt joint (431) away from the throttling structure (433) forms an outlet of the throttling module (43).

4. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic seal according to claim 3, characterized in that: The mass flow rate of the throttling hole of the throttling structure (433) satisfies: in, is the mass flow rate of gas; is the flow coefficient of the orifice; is the cross-sectional area of ​​the throttle hole, and , is the diameter of the throttle hole; is the pressure difference between the upstream and downstream of the throttling structure (433); is the pressure downstream of the orifice plate and is a constant; is the gas constant; is the gas temperature; is the specific heat ratio of gases; is the universal gas constant; is the critical pressure ratio.

5. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic seal according to claim 4, characterized in that: The valve base (1) comprises: a base body (1a), an end cover (1b) and a dynamic sealing structure (1c); The base body (1a) is a hollow cylindrical structure; Along the axial direction of the base body (1a), the hollow portion of the base body (1a) comprises a seal installation cavity and a liquid accumulation cavity which are coaxially connected; One end of the sealing element 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 chamber away from the sealing element installation chamber 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) connected to the liquid accumulation chamber; The valve inlet (1a2) is in communication with one end of the liquid accumulation chamber and the sealing element installation chamber; The end cover (1b) is detachably connected to one 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 sealing element installation cavity; The dynamic sealing structure (1c) is installed in the sealing element installation cavity; The valve stem (2) sequentially passes through the through hole of the end cover (1b) and the dynamic sealing structure (1c) to extend into the liquid accumulation chamber.

6. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic seal according to claim 5, characterized in that: The bellows (3) is sleeved on the outside of the end cover (1b), and the bellows (3) and the end cover (1b) are sealed and connected; The first channel (11) is arranged on the end cover (1b), and a plurality of the first ports are arranged at equal intervals along a ring shape on the end surface of the end cover (1b); The second port is arranged on the radial outer side of the end cover (1b).

7. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic seal according to claim 6, characterized in that: The valve stem (2) comprises: a coaxially arranged equal diameter section (2a) and a tapered section (2b); The diameter of the tapered section (2b) is gradually reduced in a direction away from the equal diameter section (2a); The second channel (21) is arranged in the equal diameter section (2a); Along the circumference of the equal diameter section (2a), a plurality of fourth ports are arranged at equal intervals.

8. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic seal according to claim 7, characterized in that: The dynamic sealing structure (1c) comprises: a spring energy storage sealing ring (1c1), a first position limiting support member (1c2) and a second position limiting support member (1c3); The first limiting support member (1c2) is arranged at one end of the sealing member installation cavity connected to the liquid accumulation cavity, and the first limiting support member (1c2) is detachably connected to the sealing member installation cavity; The second position-limiting support member (1c3) is arranged at one end of the sealing member installation cavity adjacent to the end cover (1b); The spring energy storage sealing ring (1c1) is arranged between the first position-limiting support member (1c2) and the second position-limiting support member (1c3), and opposite ends of the spring energy storage sealing ring (1c1) respectively abut against the first position-limiting support member (1c2) and the second position-limiting support member (1c3).

9. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic seal according to claim 8, characterized in that: The spring energy storage seal ring (1c1) comprises: an outer lining and an inner lining; The outer lining is a PTFE outer lining; The liner is a stainless steel spring liner, and the compression amount of the liner along the diameter direction is at least 5%.

10. The cryogenic valve assembly with integrated valve stem anti-icing and dynamic seal according to claim 9, 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 micrometers; The valve stem (2) is a stainless steel metal stem, wherein the surface roughness Ra of the equal diameter section (2a) of the valve stem (2) is less than or equal to 0.8 micrometers; The hardness of the valve stem (2) is greater than 150 HRB; The bellows (3) is a bellows made of PTFE material; The bellows (3) meets the following requirements: in, is the length of the hollow cavity of the bellows (3), is the wall thickness of the bellows (3), is the corrugation depth of the bellows (3), is the minimum compressed length of the bellows (3), is the maximum length of the bellows (3) stretched, is the wave number of the bellows (3); The first gas source module (41) comprises: a first gas cylinder (411) and a first control valve (412); The second gas source module (42) comprises: 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), the inner diameter of the first channel (11) is larger than the aperture of the throttling hole, and the inner diameter of the second channel (21) is larger than the inner diameter of the first channel (11), and the opening diameter of the fourth port is smaller 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), the inner diameter of the second channel (21) is larger than the aperture of the throttling hole, and the inner diameter of the first channel (11) is larger than the inner diameter of the second channel (21), and the opening diameter of the first port is smaller than the inner diameter of the second channel (21).

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