A cryogenic propellant fill connector

Abstract

The utility model discloses a low temperature propellant filling connector, comprising: cylindrical outer tube, the deformation compensation pipe of sleeveing in the outer tube, the both ends of outer tube and deformation compensation pipe are sealed connection respectively, to form the closed cavity between outer tube, deformation compensation pipe.

Description

Technical Field

[0001] This utility model relates to the field of aerospace technology, and in particular to a cryogenic propellant loading connector. Background Technology

[0002] During cryogenic medium filling, existing connectors experience significant frost and ice buildup, which severely hinders connector separation after filling. Furthermore, the extensive heat exchange between the connector and the external environment can cause the temperature of the cryogenic medium inside the pipeline to rise. Current cryogenic medium connectors primarily employ a wrapping method for insulation. Due to the complex locking and detachment structures required for connector mating, this results in multiple raised structures on the product surface, making wrapping for insulation difficult and ineffective.

[0003] In the process of developing this utility model, the applicant discovered at least the following problems in the prior art:

[0004] Existing liquid oxygen refueling connectors have many protrusions on their outer surface, making it difficult to cover and retain cold, resulting in poor performance. Utility Model Content

[0005] This utility model provides a cryogenic propellant filling connector to at least solve the problems of existing cryogenic propellant filling connectors having many protrusions on their outer surface, making it difficult to cover and keep cold, and resulting in poor performance.

[0006] To achieve the above objectives, one embodiment of this utility model provides a cryogenic propellant loading connector, comprising:

[0007] A cylindrical outer tube is fitted inside the deformation compensation tube, and the two ends of the outer tube and the deformation compensation tube are respectively sealed to form a closed cavity between the outer tube and the deformation compensation tube.

[0008] Furthermore, the sealed cavity is filled with a cryogenic condensing gas; the liquefaction temperature of the cryogenic condensing gas is less than or equal to the upper limit of the condensation temperature and greater than the lower limit of the condensation temperature; the upper limit of the condensation temperature is set as the temperature of the cryogenic propellant plus a preset condensation temperature tolerance; the preset condensation temperature tolerance is greater than 80 to 100 degrees Celsius; preferably, the lower limit of the condensation temperature is less than the ambient temperature, which is the temperature under the working environment of the connector. Preferably, the cryogenic condensing gas includes, but is not limited to: carbon dioxide gas, sulfur dioxide gas, ammonia gas, chlorine gas, propane, or hydrogen sulfide gas.

[0009] Furthermore, the connector also includes a plug;

[0010] An air inlet communicating with the enclosed cavity is provided on the outer wall of the connector, and the plug is installed in the air inlet.

[0011] Furthermore, the connector also includes a flange;

[0012] The flange includes: an annular flange plate and a flange cylinder coaxially connected to one side of the flange plate;

[0013] The flange body is a single-stepped cylindrical tube, including a large-diameter section and a small-diameter section.

[0014] The outer diameter of the flange cylinder is the same as the outer diameter of the outer pipe;

[0015] At least one first countersunk hole is provided on the stepped surface of the small diameter section of the flange body. The wall thickness of the outer wall of the first countersunk hole is greater than the wall thickness of the large diameter section of the flange body. An air inlet is provided on the outer wall of the flange body opposite one of the first countersunk holes. The air inlet is connected to the countersunk hole.

[0016] The right end of the outer tube is sealed to the end of the large-diameter section of the flange cylinder.

[0017] The right end of the deformation compensation pipe is sealed to the small diameter section of the flange cylinder end-to-end.

[0018] Furthermore, the wall thickness of the outer tube is 6-8 mm; the wall thickness of the outer wall of the first countersunk hole is 10-12 mm.

[0019] Furthermore, the deformation compensation pipe includes a corrugated compensation pipe.

[0020] Furthermore, the diameter of the inflation hole is 8 to 10 millimeters.

[0021] Furthermore, the wall thickness of the deformation compensation tube is 1.5 to 2 millimeters.

[0022] Furthermore, the connector also includes a mating seat, which is a single-stepped bore cylindrical tube;

[0023] The outer diameter of the docking seat is the same as the outer diameter of the outer tube;

[0024] The left end of the outer tube is sealed to the opposite end of the large-diameter section of the docking seat;

[0025] The left end of the deformation compensation tube is sealed to the end of the small diameter section of the docking seat.

[0026] Furthermore, the outer tube and the deformation compensation tube are made of aluminum alloy or stainless steel.

[0027] Furthermore, the material of the docking seat is aluminum alloy or stainless steel.

[0028] Furthermore, the flange is made of aluminum alloy or stainless steel.

[0029] Furthermore, the outer tube, the inner tube, the mating seat, and the flange are welded together.

[0030] The above technical solution has the following beneficial effects: The cylindrical outer tube provides a regular and smooth cylindrical outer surface, reducing the difficulty of the insulation process, facilitating the tight coverage of the insulation material, and improving the insulation effect; a deformation compensation tube is sleeved inside the outer tube. The internal channel of the deformation compensation tube is used to transport cryogenic propellant. If other non-deformable pipelines are used instead of the deformation compensation tube, they will deform due to temperature changes when transporting cryogenic propellant, causing the outer tube to deform under stress, leading to separation between the outer tube and the insulation material and reducing insulation performance. When using the deformation compensation tube, it will adapt to temperature changes and deform accordingly, thereby dissipating stress, reducing or even eliminating the stress acting on the outer tube. The outer tube will not deform, thus maintaining a tight bond between the outer tube and the insulation material and maintaining good insulation performance. A closed cavity is formed between the outer tube and the deformation compensation tube, which can reduce the temperature transfer from the inside to the outside and reduce the impact of cryogenic temperature on the outer tube. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a cross-sectional view of a cryogenic propellant loading connector, one of the embodiments of this utility model;

[0033] Figure 2 This is a perspective view of a cryogenic propellant loading connector, one of the embodiments of this utility model;

[0034] Figure 3 This is a perspective view of the flange viewed from the left side, according to one embodiment of the present utility model;

[0035] Figure 4 This is a perspective view of the flange viewed from the right side, according to one embodiment of the present utility model;

[0036] Figure 5 This is a perspective view of the docking seat viewed from the left side, according to one embodiment of the present utility model;

[0037] Figure 6 This is a perspective view of the docking seat viewed from the right side, according to one embodiment of the present invention.

[0038] The reference numerals in the attached drawings are as follows: 1. Outer tube; 2. Deformation compensation tube; 3. Enclosed cavity; 4. Inflation port; 5. Flange; 51. Flange plate; 52. Flange body; 521. Large diameter section of flange body; 522. Small diameter section of flange body; 523. First countersunk hole; 53. First threaded countersunk hole; 54. First circular groove; 6. Butt joint; 61. Large diameter section of butt joint; 62. Small diameter section of butt joint; 63. Second threaded countersunk hole; 64. Second countersunk hole; 65. Second circular groove. Detailed Implementation

[0039] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0040] like Figure 1 and Figure 2 As shown, this utility model embodiment provides a cryogenic propellant filling connector, including: a cylindrical outer tube 1 and a deformation compensation tube 2 sleeved inside the outer tube 1. The two ends of the outer tube 1 and the deformation compensation tube 2 are respectively sealed and connected to form a closed cavity 3 between the outer tube 1 and the deformation compensation tube 2.

[0041] In some embodiments, the outer surface of the cylindrical outer tube is a cylindrical surface, which is used to cover the outer tube with insulation material. This reduces the difficulty of the insulation process, facilitates tight coverage of the insulation material, and improves the insulation effect. The pipe inside the deformation compensation pipe 2 is used to transport cryogenic propellant. The two ends of the outer tube 1 and the deformation compensation pipe 2 can be directly sealed before connecting to other pipeline devices, or flanges or connecting seats can be provided at both ends of the outer tube 1 and the deformation compensation pipe 2. Connectors can be connected to other pipeline devices through flanges or connecting seats. The sealed connection between the outer tube 1, the deformation compensation pipe 2, and the connecting seats or flanges at both ends constitutes a closed cavity 3. The closed cavity provides thermal insulation, reduces the temperature transfer from the cryogenic propellant in the deformation compensation pipe 2 to the outer tube 1, and reduces or even avoids the deformation of the outer tube 1. Cryogenic propellants include, but are not limited to, liquid oxygen, liquid hydrogen, liquid methane, or cryogenic kerosene.

[0042] The embodiments of this invention have the following technical effects: The cylindrical outer tube provides a regular and smooth cylindrical outer surface, reducing the difficulty of the insulation process, facilitating the tight coverage of the insulation material, and improving the insulation effect; a deformation compensation tube is sleeved inside the outer tube. The channel inside the deformation compensation tube is used to transport cryogenic propellant. If other non-deformable pipelines are used instead of the deformation compensation tube, the non-deformable pipelines will deform due to temperature changes when transporting cryogenic propellant, causing the outer tube to deform under stress, leading to separation between the outer tube and the insulation material and reducing insulation performance. When using the deformation compensation tube, it will adapt to temperature changes and deform accordingly, thereby dissipating stress, reducing or even eliminating the stress acting on the outer tube, preventing deformation of the outer tube, thus maintaining a tight bond between the outer tube and the insulation material and maintaining good insulation performance. A closed cavity is formed between the outer tube and the deformation compensation tube, which can reduce the temperature transfer from the inside to the outside and reduce the impact of cryogenic temperature on the outer tube.

[0043] Furthermore, the sealed cavity 5 is filled with a cryogenic condensing gas; the liquefaction temperature of the cryogenic condensing gas is less than or equal to the upper limit of the condensation temperature and greater than the lower limit of the condensation temperature; the upper limit of the condensation temperature is set as the temperature of the cryogenic propellant plus a preset condensation temperature tolerance; the preset condensation temperature tolerance is greater than 80 to 100 degrees Celsius; preferably, the lower limit of the condensation temperature is less than the ambient temperature, which is the temperature under the working environment of the connector. Preferably, the cryogenic condensing gas includes, but is not limited to: carbon dioxide gas, sulfur dioxide gas, ammonia gas, chlorine gas, propane, or hydrogen sulfide gas. The liquefaction (sublimation) temperature of carbon dioxide at standard atmospheric pressure (101.325 kPa) is approximately -78.5°C. Carbon dioxide has the advantages of being easy to prepare and safe and reliable in this respect. Gases similar to carbon dioxide include: sulfur dioxide (SO2), with a liquefaction temperature of approximately -10°C under standard atmospheric pressure; characteristics: sulfur dioxide is also an acidic gas with a pungent odor, readily soluble in water, and its liquefaction temperature is significantly higher than that of carbon dioxide, but it is still considered a relatively easily liquefied gas in industry; ammonia (NH3), with a liquefaction temperature of approximately -33.34°C under standard atmospheric pressure; characteristics: ammonia is extremely soluble in water, has a strong pungent odor, and can be liquefied at room temperature by pressurizing it to approximately 0.7-0.8 MPa, and is widely used in the refrigeration and chemical industries; Chlorine (Cl2), with a liquefaction temperature of approximately -34.6°C under standard atmospheric pressure, is a yellowish-green, toxic gas with a strong, pungent odor. It is an oxidizing gas and relatively easy to liquefy. Propane (C3H8), with a liquefaction temperature of approximately -42.1°C under standard atmospheric pressure, is a major component of liquefied petroleum gas (LPG). It can be liquefied under pressure at room temperature and is widely used as a fuel. Hydrogen sulfide (H2S), with a liquefaction temperature of approximately -60.4°C under standard atmospheric pressure, has a rotten egg odor, is toxic, and flammable. Its liquefaction temperature is slightly higher than that of carbon dioxide, and it is also a liquefiable gas. Other gases besides carbon dioxide used in the low-temperature condensing gas in this embodiment of the invention are generally corrosive or toxic. Preferably, the low-temperature condensing gas includes carbon dioxide gas.

[0044] In some embodiments, the sealed cavity is filled with cryogenic condensed gas. When cryogenic propellant is supplied, the cryogenic condensed gas in the sealed cavity will liquefy or even solidify (e.g., carbon dioxide gas will liquefy or even solidify into dry ice), thereby turning the sealed cavity into a vacuum state and improving the thermal insulation effect. Preferably, during the inflation period or when the cryogenic condensed gas is in a gaseous state under operating conditions, the pressure of the cryogenic condensed gas in the sealed cavity should be approximately equal to that of the external environment. When cryogenic propellant is not supplied, the cryogenic condensed gas re-vaporizes into a gas, thereby maintaining a substantially equal pressure inside and outside the sealed cavity when the connector is idle or not in use, ensuring that the pressure difference between the inside and outside of the sealed cavity is essentially the same, and preventing fatigue damage to the materials constituting the sealed cavity due to continuous pressure difference. For example, filling the sealed cavity with carbon dioxide gas, since the temperature of liquid oxygen is -180 degrees Celsius and the liquefaction temperature of carbon dioxide gas is -60 degrees Celsius, when liquid oxygen is supplied, the carbon dioxide gas in the sealed cavity will liquefy or even solidify into a solid state, thereby turning the sealed cavity into a vacuum state and improving the thermal insulation effect. Preferably, the pressure of carbon dioxide gas in the sealed cavity is basically the same as that of the external environment when no cryogenic propellant is being supplied under normal temperature or operating conditions. When liquid oxygen is not being supplied, the carbon dioxide is re-vaporized into gas, thereby maintaining the pressure inside and outside the sealed cavity basically the same when the connector is idle or not in use, so that the pressure difference between the inside and outside of the sealed cavity is basically the same, and avoiding fatigue damage to the materials constituting the sealed cavity due to continuous pressure difference.

[0045] The embodiments of this invention have the following technical effects: The sealed cavity is filled with carbon dioxide gas. Under normal temperature or operating conditions, when no cryogenic propellant is being supplied, the carbon dioxide remains in a gaseous state, maintaining a basic pressure balance between the sealed cavity and the outside environment. The connector is not supplying cryogenic propellant for a relatively long period, during which the outer tube will not experience a significant internal and external pressure difference, preventing fatigue damage to the structure constituting the sealed cavity due to continuous pressure differential. During cryogenic propellant supply, the carbon dioxide liquefies or even solidifies, creating a vacuum within the sealed cavity. This isolates heat transfer from the inside to the outer tube, reducing or preventing deformation of the outer tube, maintaining a tight bond between the outer tube and the insulation material, and improving insulation performance and stability.

[0046] Furthermore, the connector also includes a plug; an inflation hole 4 communicating with the sealed cavity 3 is provided on the outer wall of the connector, and the plug is installed in the inflation hole 4 to seal the inflation hole 4 and prevent the leakage of the low-temperature condensed gas filled into the sealed cavity 3. In some embodiments, the specific location of the inflation hole 4 on the outer wall can be a cylindrical outer wall or the outer wall of the two end faces. The cylindrical outer wall can be on the outer wall of the cylindrical outer tube 1, or on the outer wall of the cylindrical pipe that is extended from both ends of the cylindrical outer tube 1. A long flexible tube is inserted deep into the sealed cavity 3 through the inflation hole 4, and low-temperature condensed gas is introduced through the long flexible tube. As the low-temperature condensed gas enters, the air originally in the sealed cavity 3 will overflow along the gap between the inflation hole 4 and the long flexible tube, and eventually the sealed cavity 3 will be filled with low-temperature condensed gas. After inflation is completed, the plug is inserted into the inflation hole 4 and welded to the inflation hole 4 to seal the inflation hole 4. Preferably, the plug is made of the same material as the structure constituting the air inlet 4. Preferably, the plug is an aluminum plug or a stainless steel plug.

[0047] Furthermore, such as Figure 3 and Figure 4 As shown, the connector also includes a flange 5;

[0048] The flange 5 includes: an annular flange 51 and a flange cylinder 52 coaxially connected to one side of the flange 51; specifically, the annular flange 51 is sleeved on the right side of the flange cylinder 52.

[0049] The flange body 52 is a single-stepped cylindrical tube, including a large-diameter section 521 and a small-diameter section 522.

[0050] The outer diameter of the flange cylinder 52 is the same as the outer diameter of the outer pipe 1;

[0051] At least one first countersunk hole 523 is provided on the stepped surface of the small diameter section 522 of the flange body. The wall thickness of the outer wall of the first countersunk hole 523 is greater than the wall thickness of the large diameter section 521 of the flange body. An air inlet 4 is provided on the outer wall of the flange body 52, opposite one of the first countersunk holes 523. The air inlet 4 is in communication with the first countersunk hole 523.

[0052] The right end of the outer tube 1 is sealed to the end of the large diameter section 521 of the flange cylinder.

[0053] The right end of the deformation compensation pipe 2 is sealed to the end of the small diameter section 522 of the flange cylinder.

[0054] Preferably, a plurality of first threaded countersunk holes 53 are provided circumferentially on the outer wall of the flange body corresponding to the small diameter section of the flange body; the first threaded countersunk holes 53 are used to connect the connector to other devices.

[0055] Preferably, the right end of the flange cylinder 52 protrudes from the flange 51, and the outer peripheral end face of the right end of the flange cylinder 52 is a conical surface; when connected to other devices with flared interfaces, the right end of the flange cylinder 52 can automatically center after being connected to the flared interface.

[0056] Preferably, the right end face of the flange cylinder 52 is provided with at least one first circular groove 54 coaxial with the flange cylinder 52, and a first sealing ring is provided in the first circular groove 54. When connected to other devices, the right end of the flange cylinder 52 is sealed by the first sealing ring when it is pressed against other devices.

[0057] In some embodiments, the outer wall thickness of the first countersunk hole 523 is greater than that of the outer tube 1 and also greater than that of the large-diameter section 521 of the flange body. A plug needs to be installed in the inflation hole, which is welded into the inflation hole. If the wall thickness of the inflation hole is too thin, it will cause deformation of the wall structure near the inflation hole. If the inflation hole is located on the outer tube 1, the wall thickness of the outer tube 1 needs to be made relatively thick, which will increase the overall weight of the connector. This requires increasing the fastening force of the connection part of the connector and the separation force when separating the arrow body and the connector, thus affecting the overall design of the system outside the connector. By setting the inflation hole in the small-diameter section 522 of the flange body, the outer wall thickness at the location of the first countersunk hole 523 with the inflation hole 4 can be made thicker than that of the outer tube 1. This eliminates the need to increase the wall thickness of the entire outer tube 1, thus not significantly increasing the overall weight of the connector, and also ensuring that the tube wall near the inflation hole does not deform during the welding of the plug. At least one first countersunk hole 523 is provided on the stepped surface of the small diameter section 522 of the flange body, which can reduce the weight of the flange while maintaining the mechanical structural strength of the flange, thereby reducing the weight of the connector.

[0058] Furthermore, the wall thickness of the outer tube 1 is 6-8 mm; the wall thickness of the outer wall of the first countersunk hole 523 is 10-12 mm. Preferably, the large-diameter section 521 of the flange cylinder has the same wall thickness as the outer tube 1.

[0059] In some embodiments, the advantages of having a wall thickness of 6 to 8 mm for the outer tube 1 are: it provides sufficient mechanical strength to effectively prevent the sealed cavity from expanding, deforming, or rupturing under an internal pressure of 1 MPa; it ensures that the structural integrity of the cavity is not affected during low-temperature contraction, avoiding failure due to "cold brittleness"; it has high thermal conductivity, which helps to quickly and evenly distribute cold energy, reduce local supercooling and thermal stress, and improve temperature control accuracy; it can reduce deformation caused by pressure fluctuations, ensure sealing performance, maintain high vacuum, and its low coefficient of thermal expansion means that the dimensions change little with temperature, maintaining the stability and insulation effect of the vacuum interlayer. The wall thickness of the outer wall of the first countersunk hole 523 is 10 to 12 mm, so the wall thickness of the air filling hole is 10 to 12 mm, effectively preventing deformation of the sidewall near the air filling hole during welding. With the flange cylinder large-diameter section 521 and the outer tube 1 having the same wall thickness and material, their thermal deformation is synchronized, which can maintain the stability of the structural connection. Considering the heat insulation and stress relief effects of the connector's closed cavity and the deformation compensation pipe, the thermal deformation of the flange cylinder large-diameter section 521 and the outer tube 1 is very small.

[0060] Furthermore, the deformation compensation tube 2 includes a corrugated compensation tube; in some conventional technologies, the corrugated tube is located on the outer surface, and when the corrugated tube deforms, it can cause the heat insulation layer to detach from the outer surface of the connector. In some embodiments of the present invention, the cryogenic propellant transported in the deformation compensation tube 2 is at a very low temperature, for example, the temperature of liquid oxygen is -180 degrees Celsius. The cryogenic propellant (e.g., cryogenic liquid oxygen) can cause uneven deformation of the connector. By setting the deformation compensation tube as a corrugated compensation tube, when the inner tube deforms due to the influence of the cryogenic propellant (the inner tube deforms due to cold), the stress generated by the deformation will be dissipated by the self-adaptive deformation of the inner tube itself. The relevant stress will not cause the outer tube to deform. Therefore, when the connector is covered with a heat insulation layer, the heat insulation layer can always maintain a tight and stable contact with the outer surface of the connector, improving the stability of the heat insulation effect.

[0061] Furthermore, the diameter of the inflation hole 4 is 8 to 10 millimeters. When using a hose to inflate cryogenic condensed gas, air needs to be squeezed out through the gap between the inflation hole and the hose. If the diameter of the inflation hole is too large, the cryogenic condensed gas is prone to overflow. If the inflation hole is too small, the gas replacement time is too long. An inflation hole diameter of 8 to 10 millimeters can balance the above problems and achieve better inflation efficiency.

[0062] Furthermore, the wall thickness of the deformation compensation tube 2 is 1.5 to 2 mm. In some embodiments, the pressure of the cryogenic propellant (e.g., liquid oxygen) in the inner tube is 1 MPa to 1.1 MPa, and the temperature is approximately -183 degrees Celsius. To quickly adapt to operating parameters within this range, the wall thickness of the deformation compensation tube is set to 1.5 to 2 mm.

[0063] The embodiments of the present invention have the following technical effects: the deformation compensation pipe 2 has a thickness of 1.5 to 2 mm, which has good thermal conductivity and can make the entire pipeline reach a stable low temperature state more quickly, reducing local overheating; the structure is lightweight, the pipeline itself is light, installation is convenient, and the requirements for the supporting structure are low; for a pressure of 1 MPa, a wall thickness of 1.5 to 2 mm can meet the strength requirements under low pressure conditions, and this thickness is also economical; it has good low temperature resistance, and when the material is aluminum alloy, it can generally maintain good toughness at low temperatures and is not easy to become brittle.

[0064] Furthermore, such as Figure 5 and Figure 6 As shown, the connector also includes a mating seat 6, which is a single-stepped cylindrical tube.

[0065] The outer diameter of the docking seat 6 is the same as the outer diameter of the outer tube 1;

[0066] The left end of the outer tube 1 is sealed to the end of the large diameter section 61 of the docking seat.

[0067] The left end of the deformation compensation pipe 2 is sealed to the end of the small diameter section 62 of the docking seat.

[0068] Preferably, the wall thickness of the large-diameter section 61 of the docking seat is the same as the wall thickness of the outer tube 1; a plurality of second threaded countersunk holes 63 are provided axially on the outer wall of the docking seat 6 corresponding to the small-diameter section of the docking seat; the second threaded countersunk holes 63 are used for connecting the connector to other devices.

[0069] Preferably, the outer peripheral end face of the left end of the docking seat 6 is a conical surface; when connected to other devices with flared interfaces, the left end of the docking seat 6 can automatically center after being connected to the flared interface.

[0070] Preferably, the left end face of the docking seat 6 is provided with at least one second circular groove 65 coaxial with the docking seat 6, and a second sealing ring is provided in the second circular groove 65. When connected with other devices, the left end of the docking seat 6 is sealed by the second sealing ring when it is pressed against other devices.

[0071] Preferably, at least one second countersunk hole 64 is provided on the stepped surface of the small diameter section 62 of the docking seat, which can reduce the weight of the docking seat while maintaining the mechanical structural strength of the docking seat, thereby reducing the weight of the connector.

[0072] Furthermore, the outer tube 1 and the deformation compensation tube 2 are made of aluminum alloy or stainless steel.

[0073] Furthermore, the material of the docking seat 6 is aluminum alloy or stainless steel.

[0074] Furthermore, the flange 5 is made of aluminum alloy or stainless steel.

[0075] In some embodiments, the outer tube 1, the deformation compensation tube 2, the docking seat 6 and the flange 5 are made of aluminum alloy or stainless steel, preferably 5A06 aluminum alloy or 304 stainless steel 1Cr18Ni9.

[0076] (1) 1Cr18Ni9 (304 stainless steel) has the following advantages as a production material for liquid oxygen filling connectors:

[0077] 1Cr18Ni9, as a classic austenitic stainless steel, exhibits excellent performance in the harsh working environment of liquid oxygen-filled connectors, meeting the special requirements of connectors for materials under extreme conditions.

[0078] a. Exceptional Low-Temperature Toughness: The extreme low temperatures (-183℃) of liquid oxygen environments place extremely high demands on the low-temperature resistance of materials. 1Cr18Ni9 stainless steel has a face-centered cubic crystal structure, which does not undergo a brittle transformation under low-temperature conditions. Instead, it maintains or even enhances its impact toughness. This characteristic ensures that the connector will not fracture brittlely even when subjected to sudden temperature changes during liquid oxygen filling, greatly improving the safety and reliability of the equipment. The stability of its austenitic structure at low temperatures is the fundamental reason for its superior low-temperature resistance.

[0079] b. Excellent corrosion resistance: Liquid oxygen refueling systems require prolonged contact with high-purity oxidants, placing extremely high demands on the corrosion resistance of materials. The approximately 18% chromium content in 1Cr18Ni9 forms an extremely thin and dense chromium oxide passivation film on its surface. This film effectively prevents further corrosion of the substrate, significantly improving the material's corrosion resistance in oxidizing media. This characteristic allows the connector to withstand the highly oxidizing environment of liquid oxygen for extended periods, preventing contamination or failure caused by material corrosion.

[0080] c. Excellent processing and welding properties: 1Cr18Ni9 can achieve high-quality welds using conventional welding methods, facilitating the manufacture of complex connector structures. After solution treatment, the material exhibits tensile strength ≥520MPa, yield strength ≥205MPa, and elongation ≥40%, demonstrating excellent strength and ductility to meet the mechanical performance requirements of various connector components. Furthermore, the material's non-magnetic nature avoids potential safety hazards caused by magnetization in liquid oxygen environments.

[0081] (2) 5A06 aluminum alloy has the following advantages as a production material for liquid oxygen refueling connectors:

[0082] 5A06 aluminum alloy, as an Al-Mg-Mn series rust-resistant aluminum alloy, has advantages in the lightweight design of liquid oxygen filling connectors.

[0083] a. Excellent lightweight properties: The density of 5A06 aluminum alloy is only 2.64 g / cm³. 3 It is approximately one-third the size of 1Cr18Ni9 stainless steel. This characteristic allows connectors made of 5A06 aluminum alloy to significantly reduce system weight while maintaining high specific strength, with tensile strength ≥315MPa and yield strength ≥160MPa, which can meet the strength requirements of connectors for liquid oxygen filling.

[0084] b. Excellent low-temperature performance and corrosion resistance: 5A06 aluminum alloy maintains good plasticity and toughness in low-temperature environments. The dense oxide film (Al2O3 / MgO) formed on its aluminum-magnesium alloy surface effectively resists oxidation and corrosion in liquid oxygen environments. Especially in marine environments with high chloride ion content, 5A06 exhibits excellent resistance to stress corrosion cracking, with an annual corrosion rate far lower than that of ordinary carbon steel materials, ensuring the long-term reliability of connectors in harsh environments.

[0085] c. Excellent weldability: 5A06 aluminum alloy exhibits extremely excellent weldability. When using argon arc welding, the weld strength can reach 90%-95% of the base metal.

[0086] Furthermore, the outer tube 1, deformation compensation tube 2, mating seat 6, and flange 5 are connected by welding. After welding, all welds require X-ray flaw detection to prevent internal defects such as porosity and cracks. Preferably, when the wall thickness of the deformation compensation tube is set to 1.5 to 2 mm, the welding method between the outer tube 1, the deformation compensation tube 2, the mating seat 6, and the flange 5 is laser filler wire welding, which reduces the heat input to the outer tube 1, deformation compensation tube 2, mating seat 6, and flange 5 during welding, thus preventing deformation. Welding simplifies the connection structure, avoiding the use of complex mechanical connections and sealing structures to connect the outer tube 1, deformation compensation tube 2, mating seat 6, and flange 5, and welding itself also provides good sealing performance.

[0087] The technical solutions of the present invention will be described in detail below with reference to specific application examples. For technical details not described in the implementation process, please refer to the relevant description above.

[0088] In the following embodiments, carbon dioxide gas is used as the cryogenic condensing gas and liquid oxygen is used as the cryogenic propellant. For the vacuum cavity insulation scheme, the present invention discloses the composition and structure of the vacuum cavity, and provides technical details such as setting a vacuum compensation bellows and filling the vacuum cavity with carbon dioxide for insulation.

[0089] The liquid oxygen refueling connector cooling system mainly consists of the following components:

[0090] 1. Body vacuum cavity for cold insulation

[0091] The vacuum chamber is welded together from a docking seat, flange, outer wall (outer tube 1), and compensator (corrugated compensator or inner tube 2); the liquid oxygen in the connector is -180 degrees Celsius, and the liquefaction temperature of carbon dioxide is -60 degrees Celsius, so that the carbon dioxide in the vacuum chamber is liquefied to form a vacuum.

[0092] The compensator includes a bellows, which is made of aluminum.

[0093] The welding of the outer wall in three parts takes into account both process and cost.

[0094] All parts are manufactured using 5A06 aluminum alloy, which has excellent weldability.

[0095] The docking seat, outer wall, and compensator are all machined using CNC machining. The compensator is made by rolling formed aluminum tubes and then machining them.

[0096] Because the compensator needs to compensate for the uneven deformation caused by cryogenic liquid oxygen to the overall product, its wall thickness is relatively thin, specifically ranging from 1.5 to 2 mm, and the applicable operating parameters are pressure from 1 MPa to 1.1 MPa and temperature from -181.5 degrees Celsius.

[0097] The welding must be completed using TIG welding (tungsten inert gas welding).

[0098] Before welding the docking seat, outer wall, and compensator, rough machining should be performed, leaving sufficient machining allowance.

[0099] After welding is completed, all welds need to be inspected by X-ray to avoid unqualified pores and cracks inside;

[0100] After the main body is welded, fine machining is then performed.

[0101] During the rough machining stage of the flange, air inlet holes are drilled in the side wall;

[0102] After the main body is welded, a cavity is formed inside the four parts: the mating seat, the outer wall, the compensator, and the flange.

[0103] Insert the hose through the air inlet of the flange, leading directly to the deepest part of the cavity;

[0104] Fill the cavity with carbon dioxide until the air inside the cavity is completely replaced with carbon dioxide.

[0105] Remove the carbon dioxide replacement tube, plug the filling port with an aluminum plug, and weld it in place. At this point, the cavity is filled with carbon dioxide gas, and this method is less prone to leakage.

[0106] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process may be rearranged without departing from the scope of this disclosure. The appended method claims provide elements of various steps in an exemplary order and are not intended to limit the scope to the specific order or hierarchy described.

[0107] In the above detailed description, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0108] The disclosed embodiments have been described above to enable any person skilled in the art to implement or use this invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not limited to the embodiments given herein, but is consistent with the widest scope of the principles and novel features disclosed in this application.

[0109] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations falling within the scope of the appended claims. Furthermore, the term "comprising" as used in the specification or claims is used in a manner similar to the term "including." Additionally, the use of any term "or" in the specification of the claims is intended to mean "non-exclusive or."

[0110] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A cryogenic propellant loading connector, characterized in that, include: A cylindrical outer tube (1) and a deformation compensation tube (2) are fitted inside the outer tube (1). The two ends of the outer tube (1) and the deformation compensation tube (2) are sealed and connected to form a closed cavity (3) between the outer tube (1) and the deformation compensation tube (2).

2. The cryogenic propellant loading connector as described in claim 1, characterized in that, The enclosed cavity (3) is filled with low-temperature condensing gas.

3. The cryogenic propellant loading connector as described in claim 1, characterized in that, The connector also includes a plug; An air inlet (4) communicating with the closed cavity (3) is provided on the outer wall of the connector, and the plug is installed in the air inlet (4).

4. The cryogenic propellant loading connector as described in claim 1, characterized in that, The connector also includes a flange (5); The flange (5) includes: an annular flange (51) and a flange cylinder (52) coaxially connected to one side of the flange (51). The flange body (52) is a single-step bore cylindrical tube, including a large-diameter section (521) and a small-diameter section (522). The outer diameter of the flange cylinder (52) is the same as the outer diameter of the outer pipe (1); At least one first countersunk hole (523) is provided on the stepped surface of the small diameter section (522) of the flange body. The wall thickness of the outer wall of the first countersunk hole (523) is greater than the wall thickness of the large diameter section (521) of the flange body. An air inlet (4) is provided on the outer wall of the flange body (52) opposite one of the first countersunk holes (523). The air inlet (4) is connected to the countersunk hole (523). The right end of the outer tube (1) is sealed to the end of the large diameter section (521) of the flange cylinder. The right end of the deformation compensation pipe (2) is sealed to the end of the small diameter section (522) of the flange cylinder.

5. The cryogenic propellant loading connector as described in claim 4, characterized in that, The outer tube (1) has a wall thickness of 6-8 mm; the outer wall of the first countersunk hole (523) has a wall thickness of 10-12 mm.

6. The cryogenic propellant loading connector as described in claim 1, characterized in that, The deformation compensation pipe (2) includes a corrugated compensation pipe.

7. The cryogenic propellant loading connector as described in claim 3 or 4, characterized in that, The diameter of the air inlet (4) is 8 to 10 millimeters.

8. The cryogenic propellant loading connector as described in claim 1, characterized in that, The wall thickness of the deformation compensation tube (2) is 1.5 to 2 mm.

9. The cryogenic propellant loading connector as described in claim 1, characterized in that, The connector also includes a mating seat (6), which is a single-stepped cylindrical tube. The outer diameter of the docking seat (6) is the same as the outer diameter of the outer tube (1); The left end of the outer tube (1) is sealed to the end of the large diameter section (61) of the docking seat; The left end of the deformation compensation pipe (2) is sealed to the end of the small diameter section (62) of the docking seat.

10. The cryogenic propellant loading connector as described in claim 1, characterized in that, The outer tube (1) and the deformation compensation tube (2) are made of aluminum alloy or stainless steel.

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