69 results about "Cryogenic engineering" patented technology

The invention discloses a multifunctional integrated gas control system for a dilution refrigerator, and particularly relates to the field of refrigeration and low-temperature engineering, which comprises a liquid nitrogen cold trap, a gas buffer tank, an integrated valve box, a dilution refrigeration internal circulation pipeline, a diaphragm compressor, a roots pump, a turbo molecular pump and a vacuum suction pump set. According to the system, a highly-integrated valve box module is used and is responsible for implementing gas circuit control on different stages such as dilution refrigeration cycle starting, operation and shutdown rewarming; according to the invention, conductance optimization and heat loss reduction are carried out on gas paths with different temperature zones and different pressures, high air tightness of a full temperature zone from room temperature to extremely low temperature is ensured, the reliability and the automation degree of the dilution refrigerating machine are improved, and very positive significance is provided for practicability of a dilution refrigerating system.

The invention discloses a through-type heat exchanger for controlling heat leakage between different last cold stages of a dilution refrigerator and a manufacturing method, and particularly relates to the technical field of refrigeration and low-temperature engineering, the through-type heat exchanger comprises an inlet connecting pipe, an annular upper sealing plate, a heat exchanger shell, an annular lower sealing plate, an outlet connecting pipe and a metal sintering body, an inner wall face fixing step is fixedly arranged on the inner wall of the heat exchanger shell, the inner wall face fixing step is close to an opening in the bottom end of the heat exchanger shell, the metal sintering body is arranged in the heat exchanger shell and is tightly matched with the heat exchanger shell, and the length of the metal sintering body is slightly smaller than that of the heat exchanger shell. By arranging the metal sintering body, the heat exchange area is increased to the maximum extent within the limited volume, the porosity and the specific surface area of the metal sintering body are reasonably set, and therefore stable flowing and diffusion of the helium-3 / helium-4 mixed working medium are achieved.

The utility model relates to the technical field of low-temperature engineering, in particular to a pressure sensor helium protection structure applied to a superfluid helium negative pressure pipeline, which comprises a sealed container, and a pressure sensor on the superfluid helium negative pressure pipeline is positioned in the sealed container. A superfluid helium negative pressure pipeline connected with the pressure sensor enters the sealed container and is in sealed connection with the sealed container, the sealed container is provided with a gas inlet pipeline, and the helium source provides micro-positive pressure helium for the sealed container through the gas inlet pipeline; the pressure sensor on the superflow helium negative pressure pipeline is arranged in the sealed container, and the container is filled with micro-positive pressure helium, so that the structure can ensure that external air cannot be leaked into a negative pressure pipeline system through the pressure sensor under any condition, and the safety of the system is ensured. Therefore, external air is prevented from entering the superflow helium negative pressure pipeline when the system is shut down or micro leakage occurs at the interface of the pressure sensor, so that the pollution of the whole system is prevented.

The invention relates to the technical field of flow control and low-temperature engineering, in particular to a variable-frequency control-based flow range expansion method of a low-temperature flow standard device, which comprises the following steps of: acquiring basic working condition parameters and variable-frequency characteristic parameters of the low-temperature flow standard device through a parameter acquisition unit, and analyzing flow characteristics; a physical property parameter change rule and a flow characteristic comprehensive index are obtained, and a frequency conversion strategy is generated in combination with a frequency and flow characteristic curve; adjusting output frequency based on a frequency conversion strategy, and controlling pump rotating speed to perform flow expansion; the expansion result is verified, the expansion effect is judged, and after verification is finished, all verification results form a standardized document and are uploaded to a display terminal; the problem that continuous adjustment of the flow range from micro flow to medium and high flow is difficult is effectively solved, and the efficiency and stability of flow range expansion are improved.

The invention discloses an experimental device for testing the performance of a liquid hydrogen valve, and relates to the technical field of refrigeration and low-temperature engineering. Comprising a low-temperature medium storage system, a high-pressure purified gas storage device, a temperature measurement system, a valve test module, a vacuumizing device, a rewarming device, a gas recovery system, a leakage rate measurement system and a data acquisition system, and the low-temperature medium storage system is used for storing a low-temperature cooling medium. The temperature zone of the liquid helium can cover the liquid hydrogen, the safety of the liquid helium is far higher than that of the liquid hydrogen, the test safety is improved, the supply of the low-temperature medium can be accurately controlled, the reliable test of the valve at the preset temperature is ensured, the test requirement of the temperature range of 20K-300K is met, the application range is wider, and the application range is wider. The valve testing device can support a low-temperature environment from 20K to 300K, provides a high-pressure hydrogen condition, and meets various valve testing requirements.

The invention discloses a wide and thin steel plate with excellent low-temperature toughness for a 355MPa-grade low-temperature engineering structure and a manufacturing method of the wide and thin steel plate, and belongs to the technical field of low-carbon microalloyed steel production. The steel plate comprises the following chemical components in percentage by weight: 0.05%-0.08% of C, 0.2%-0.25% of Si, 1.45%-1.55% of Mn, less than or equal to 0.025% of P, less than or equal to 0.015% of S, 0.02%-0.04% of Nb, 0.010%-0.04% of Al, 0.003%-0.006% of N and the balance of Fe and inevitable impurities, and the total amount of other impurity elements is less than 0.05%. The manufacturing method comprises the steps of molten steel smelting, external refining and degassing, continuous casting, slab reheating, rolling and controlled cooling. The steel plate is low in cost, high in strength and toughness and capable of meeting the service safety of the steel plate for the engineering structure under the condition of-60 DEG C.

The invention relates to the field of vacuum technology and low-temperature engineering, and discloses a low-temperature cold trap device and a vacuum system.The low-temperature cold trap device comprises a shell provided with an extraction opening; the adapter piece is communicated with the shell and is provided with a channel which can be opened or closed; the condensation assembly is arranged in the shell; the cold source is arranged on the shell and exchanges heat with the condensation assembly; the driving mechanism is arranged on the shell and used for driving the condensation assembly to enter and exit from the shell along the channel. The driving mechanism drives the condensation assembly to enter and exit from the shell along the channel, the low-temperature cold trap device can be arranged in the air exhaust pipeline to achieve high cold trap working efficiency during working, the cold trap can be moved out of the air exhaust pipeline during regeneration, shutdown of the air exhaust pipeline is avoided, air exhaust work is not affected, and the service life of the low-temperature cold trap device is prolonged. Therefore, the air exhaust efficiency and the air exhaust performance of the air exhaust pipeline can be ensured.

The invention relates to the technical field of low-temperature engineering, and provides an air gap heat switch and a preparation method thereof and a low-temperature refrigerating system.The air gap heat switch comprises a supporting shell, a hot end component, a cold end component and a gas adsorption component, the hot end component and the cold end component are both arranged in the supporting shell in a sealed mode, and the gas adsorption component is connected with an air gap; a first functional coating is arranged on the surface, facing the air gap, of the hot end component and / or the cold end component, and the first functional coating is used for providing thermal insulation between the hot end component and the cold end component. The air gap heat switch has the functions of gap control and heat insulation, heat insulation is provided when the air gap heat switch is in an off state, heat conductivity is provided when the air gap heat switch is in an on state, the on-off ratio of the air gap heat switch is increased, and it is ensured that the reliability and the vibration resistance of the air gap heat switch in long-term work are enhanced.

The invention belongs to the technical field of ultralow-temperature materials, and discloses high-strength and high-toughness steel for ultralow-temperature engineering and a preparation method of the high-strength and high-toughness steel. Through ultra-low carbon, control of the chemical composition proportion of Creq content and Nieq content, and combination of a vacuum induction melting and vacuum consumable remelting duplex smelting process, the grain size grade of the novel steel is more than 6 grade, and the matrix structure is fine lath martensite and film-shaped reversed austenite with the volume fraction of 26%-50%. According to the high-strength and high-toughness steel for ultralow-temperature engineering, the room-temperature yield strength is larger than or equal to 1100 MPa, the room-temperature tensile strength is larger than or equal to 1200 MPa, the ductility is larger than or equal to 20%, the room-temperature V-type impact energy KV2 is larger than or equal to 200 J, the-196 DEG C yield strength is larger than or equal to 1300 MPa, the-196 DEG C tensile strength is larger than or equal to 1800 MPa, the ductility is larger than or equal to 20%, and the-196 DEG C V-type impact energy KV2 is larger than or equal to 60 J.

The present invention relates to the field of flow control and cryogenic engineering technology, and specifically to a flow range expansion method for a cryogenic flow standard device based on variable frequency control. The method comprises the following steps: a parameter acquisition unit is used to acquire basic operating parameters and variable frequency characteristic parameters of the cryogenic flow standard device, and the flow characteristics are analyzed to obtain a variation law of physical parameters and a comprehensive index of flow characteristics. A variable frequency strategy is generated by combining frequency and flow characteristic curves; the output frequency is adjusted based on the variable frequency strategy, and the pump speed is controlled to expand the flow; the expansion result is verified, and the expansion effect is judged. After the verification is completed, all verification results are formed into a standardized document and uploaded to a display terminal. The method effectively solves the problem of difficulty in continuously adjusting the flow range from micro flow to medium and high flow, and improves the efficiency and stability of the flow range expansion.

The invention discloses maraging stainless steel for low-temperature engineering and a preparation process thereof based on double-aging strengthening and toughening heat treatment, and belongs to the technical field of material heat treatment. The stainless steel comprises the following chemical components: 0.01 to 0.05 percent of C (carbon), 0.1 to 1.5 percent of Mn (manganese), 11.0 to 13.0 percent of Cr (chromium), 6.0 to 10.5 percent of Ni (nickel), 2.5 to 3.5 percent of Mo (molybdenum), 6.0 to 8.0 percent of Co (cobalt), 0.1 to 3.0 percent of Cu (copper), 0.1 to 0.5 percent of V (vanadium), 0.01 to 0.05 percent of Nb (niobium) and the balance of Fe (iron) and inevitable impurities. The forging with the chemical components of the stainless steel is subjected to solution treatment, then subjected to first-time aging at the temperature of 640-720 DEG C, subjected to cold treatment and then subjected to second-time aging treatment at the temperature of 420-580 DEG C; through two-time two-phase region aging treatment, the obtained maraging stainless steel has high strength and high toughness under a low-temperature condition.

This invention relates to the fields of cryogenic engineering and superconducting applications, and discloses a superconducting magnet system using a liquid neon pulsating heat pipe for nitrogen-fixed cooling. The system includes a vacuum chamber, a nitrogen-fixing chamber within the vacuum chamber, a high-temperature superconducting magnet within the nitrogen-fixing chamber, a refrigerator, a T-shaped cooling block connected to the refrigerator's cold head, and a liquid neon cryogenic pulsating heat pipe. The liquid neon cryogenic pulsating heat pipe is thermally connected to the T-shaped cooling block and to the outer wall of the nitrogen-fixing chamber. The high-temperature superconducting magnet exchanges heat with the nitrogen-fixing chamber through nitrogen fixation within the chamber, and the heat is then transferred to the outer wall of the nitrogen-fixing chamber via the liquid neon cryogenic pulsating heat pipe, and then further transferred to the high-temperature superconducting magnet via nitrogen fixation. By placing the liquid neon cryogenic pulsating heat pipe on the outer wall of the nitrogen-fixing chamber, and transferring the refrigerator's cooling capacity sequentially through the T-shaped cooling block, the liquid neon cryogenic pulsating heat pipe, the outer wall of the nitrogen-fixing chamber, and the nitrogen fixation to the high-temperature superconducting magnet, a cooling path combining the liquid neon cryogenic pulsating heat pipe and nitrogen fixation is constructed.

The invention relates to the technical field of refrigeration and low-temperature engineering, in particular to a liquid ammonia circulating device and a germanium spectrometer, the liquid ammonia circulating device comprises a storage tank, a heat exchange assembly and a circulating assembly, the storage tank is internally provided with a first cavity for storing liquid ammonia, and the liquid ammonia exchanges heat with a cold head of the germanium spectrometer extending into the first cavity; the output end and the input end of the heat exchange assembly communicate with the input end and the output end of the first cavity correspondingly to form a liquid ammonia circulation loop used for guiding and conveying liquid ammonia, and the heat exchange assembly is used for conducting heat exchange on the liquid ammonia in the liquid ammonia circulation loop; the circulation assembly is arranged between the storage tank and the heat exchange assembly and provides power for liquid ammonia circulation. By forming the liquid ammonia circulation loop, an appropriate low-temperature environment can be continuously and stably provided for the cold head of the germanium spectrometer, and experiment interruption caused by frequent supplement due to rapid volatilization of a refrigerating medium is avoided, so that the energy resolution and the detection efficiency of the spectrometer are guaranteed, and the energy scale precision of the spectrometer is improved.

The present application relates to the field of refrigeration and cryogenic engineering, and discloses an integrated jet throttling ultra-low temperature cold head device, comprising: a main jet, a limit clamp, a secondary jet, a low-pressure joint, a small orifice plate, a throttling joint, and an evaporator. The present invention utilizes the main jet to accelerate the high-pressure fluid, while maintaining the pressure difference between the fluid in the evaporator and the low-pressure channel through throttling by the small orifice plate. The secondary jet is used to mix and accelerate the high-pressure fluid and the fluid in the evaporator, causing the fluid in the evaporator to form a secondary pressure reduction, thereby ensuring that the pressure in the evaporator is further lower than that in the low-pressure channel, achieving a lower refrigeration temperature and reducing the low-pressure requirement of the low-pressure channel. In addition, the integrally welded sealing method ensures the compactness and integration of the jet and evaporator, which has a very positive significance for the practical application of ultra-low temperature throttling refrigerators.

The invention discloses an external cold trap for a dilution refrigerator, and particularly relates to the field of refrigeration and low-temperature engineering, the external cold trap comprises a liquid nitrogen tank, a purification chamber is arranged in the liquid nitrogen tank, a separation unit, a purification unit and a pre-cooling unit are sequentially arranged in an inner cavity of the purification chamber from top to bottom, and a sealing top cover is arranged at the top of the purification chamber; the sealing top cover is provided with an air inlet pipe, an air outlet pipe and a maintenance channel. According to the technical scheme, the pre-cooling unit and the separation unit are additionally arranged on the lower portion and the upper portion of the purification unit formed by activated carbon respectively, so that the heat exchange efficiency of airflow is improved, the cooling time is shortened, and the purpose of improving the purification efficiency is achieved; meanwhile, the separation unit and the copper mesh filter element form a self-purification device, so that the self-pollution effect of the cold trap is avoided; the long-term stable operation of the throttling process and the stability of long-term repeated start-up of the dilution refrigerator can be guaranteed, so that the maintenance period of the dilution refrigerator is greatly prolonged, and very positive significance is achieved for practicability of the dilution refrigerator.

The invention discloses an integrated structure for cooling an infrared detector by adopting a pulse tube refrigerator, and particularly relates to the field of refrigeration and low-temperature engineering, the integrated structure comprises a bottom plate, a compressor and the pulse tube refrigerator are respectively arranged on two sides of the top of the bottom plate, and a connecting tube is arranged between the compressor and the pulse tube refrigerator; the compressor and the pulse tube refrigerator are combined into a whole through a connecting pipe, an infrared detector is arranged on one side of the pulse tube refrigerator, and a Dewar tank is connected between the infrared detector and the pulse tube refrigerator. According to the invention, the infrared detector is installed at the cold end part of the pulse tube refrigerator in a direct coupling manner, and the adverse effect of plastic deformation of the cold end part under a large temperature gradient on the infrared detector is reduced by using the material characteristics of the Kovar bottom plate welded on the cold head; a set of detachable simple Dewar provided with an optical filter, a temperature and data signal transmission interface and a vacuum interface is manufactured, various elements required by operation of the infrared detector are combined together, and diversification and convenience of operation and maintenance are realized.

The application relates to the field of low-temperature engineering and heat transfer technology and discloses an ultralow-temperature heat pipe system based on nitrogen phase change circulation, which comprises a cold head with a first cold end, a heat pipe body with a second cold end at one end and surrounding the first cold end, the first cold end liquefying nitrogen in the space surrounded by the second cold end into liquid nitrogen, the other end of the heat pipe body being a hot end, the heat pipe body internally having a liquid nitrogen conveying channel communicating the second cold end and the hot end and a nitrogen backflow channel communicating the hot end and the second cold end, and a vacuum interlayer arranged outside the heat pipe body and used for heat preservation of the heat pipe body. The application takes nitrogen as a working medium, completes the phase change circulation of liquefaction and vaporization in the system and does not discharge to the outside, thereby avoiding the safety hazard of the increase of nitrogen concentration caused by the discharge of nitrogen vaporized after liquid nitrogen cooling into the room in the traditional flowing liquid nitrogen cooling mode; the system does not need to frequently supplement liquid nitrogen, can be long-term and stable in operation, improves the use efficiency of the equipment to be cooled, and the setting of the vacuum interlayer improves the refrigeration efficiency.

The invention discloses a high-strength stainless steel wire rod and casting for low-temperature engineering and a preparation method and application thereof, and belongs to the technical field of metal materials. The wire rod or the casting comprises the following chemical components in percentage by mass: less than or equal to 0.02% of C, less than or equal to 0.60% of Si, less than or equal to 0.75% of Mn, less than or equal to 12.00% and less than or equal to 12.50% of Cr, less than or equal to 5.50% and less than or equal to 6.50% of Ni, less than or equal to 7.50% and less than or equal to 8.00% of Co, less than or equal to 3.50% and less than or equal to 4.00% of Mo, less than or equal to 0.01% of P, less than or equal to 0.006% of S, less than or equal to 0.004 ppm of [O], less than or equal to 0.005 ppm of [N], less than or equal to 3 ppm of [H] and the balance of Fe. The high-strength stainless steel casting for low-temperature engineering is prepared by developing a high-purity wire rod as an intermediate raw material and performing vacuum remelting casting by taking the wire rod as a base material, and the purity and the mechanical property of the high-strength stainless steel casting meet the requirements of the aviation field on the high-strength stainless steel casting.

The application belongs to the technical field of high-strength stainless steel, and provides a high-strength non-magnetic austenitic stainless steel rod suitable for nuclear fusion armor and a manufacturing method thereof.The high-strength non-magnetic austenitic stainless steel rod of the application eliminates high-temperature delta-ferrite and M23C6, so that it has excellent matching of strength and toughness and intergranular corrosion resistance at low temperature.The yield strength of the high-strength non-magnetic austenitic stainless steel rod of the application is greater than or equal to 1250 MPa at 4.2K liquid helium temperature, the tensile strength is greater than or equal to 1700 MPa, the elongation is greater than or equal to 25%, and the magnetic permeability is less than or equal to 1.02.The high-strength non-magnetic austenitic stainless steel rod of the application is an austenitic non-magnetic high-strength stainless steel, and can be directly applied to structural parts such as conductor armor of nuclear reactors and the like, and can also be popularly applied to high-strength stainless parts required in low-temperature engineering and other related fields, and has a broad market prospect.

The invention discloses a single-cold-type refrigeration device and a refrigeration method, and relates to the technical field of refrigeration and low-temperature engineering, a magnetic suspension bearing assembly is characterized in that firstly, friction of a traditional mechanical bearing is thoroughly eliminated through non-contact suspension of a radial magnetic bearing and a thrust bearing, and real-time feedback of a displacement sensor is matched between the radial magnetic bearing and a main shaft; the main shaft can be kept stable during high-speed rotation, vibration loss is reduced, meanwhile, friction loss of the thrust bearing approaches zero, energy consumption of the whole machine is further reduced, lubricating oil does not need to participate in axial supporting, the situation that lubricating oil enters a meshing face of the scroll plate, and consequently an oil film is blocked is avoided, and the service life of the scroll plate is prolonged. The radial magnetic bearing and the thrust bearing are uniformly controlled by the magnetic suspension controller to form a full-dimensional non-contact supporting system with radial constraint and axial balance, the magnetic suspension technology breaks through the performance bottleneck of a traditional scroll compressor, and the scroll compressor has remarkable advantages in the aspects of energy efficiency, stability and service life.

The application discloses a single-cooling type refrigerating device and a refrigerating method, relates to the technical field of refrigeration and low-temperature engineering, and discloses a magnetic suspension bearing assembly, which is first suspended by a radial magnetic bearing and a thrust bearing without contact, thereby completely eliminating the friction of a traditional mechanical bearing, and the real-time feedback of a displacement sensor matched between the radial magnetic bearing and a main shaft can ensure that the main shaft is stable during high-speed rotation and reduce the loss of vibration, and meanwhile, the friction loss of the thrust bearing tends to be zero, further reducing the energy consumption of the whole machine, and the axial support does not need to involve lubricating oil, so that the situation that the oil film is blocked due to the entry of the lubricating oil into the meshing surface of the scroll disc is avoided, the radial magnetic bearing and the thrust bearing are uniformly controlled by a magnetic suspension controller, a full-dimension non-contact support system of radial constraint and axial balance is formed, and the magnetic suspension technology breaks through the performance bottleneck of a traditional scroll compressor and has significant advantages in energy efficiency, stability and service life.

The invention belongs to the field of metallurgy, and particularly relates to a method for improving the strength and impact toughness of a 3.5 Ni steel plate in a low-temperature environment. According to the technical scheme, according to the method for improving the strength and the impact toughness of the 3.5 Ni steel plate in the low-temperature environment, the addition amount of Mo in the 3.5 Ni steel plate and a heat treatment technology are accurately adjusted and controlled, a nanometer coherent B2 precipitated phase with specific crystallographic characteristics is formed in an induction mode, and the impact energy of the 3.5 Ni steel plate at the temperature of-196 DEG C reaches 100 J or above. According to the method for improving the strength and the impact toughness of the 3.5 Ni steel plate in the low-temperature environment, the impact energy of the 3.5 Ni steel plate at the temperature of-196 DEG C reaches 100 J or above, a low-cost and high-performance low-temperature structural material is provided for the fields of liquefied natural gas storage and transportation, cryogenic engineering and the like, and the application boundary of the low-Ni steel plate under the extreme working condition can be expanded.

The present application belongs to the technical field of refrigeration and low temperature engineering, and relates to a kind of contactless natural convection refrigeration device of acoustic levitation droplet, including cooling cavity, ultrasonic assembly, semiconductor refrigeration assembly, position adjusting assembly, droplet injection unit, shooting unit and control unit.The present application can actively maintain the stable suspension state of liquid droplet at the acoustic pressure node while carrying out contactless natural convection refrigeration on the liquid droplet.By coupling acoustic levitation and natural convection cooling, the liquid droplet freely hovers in the standing wave acoustic field, completely avoids the heterogeneous nucleation effect caused by container wall contact, and dynamically compensates the morphology fluctuation in the cooling process by using real-time morphology feedback and closed-loop adjustment of acoustic field spacing, so that the liquid droplet is stably suspended, which not only can simulate the rapid phase transition behavior of supercooled liquid droplet in motion or collision process, ensure the accuracy of dynamic simulation of supercooled liquid droplet icing process and the effectiveness of supercooled liquid droplet collision mechanism research, but also can avoid unstable liquid droplet morphology.

The invention discloses a high-strength steel plate for a high-efficiency low-cost 690MPa-grade low-temperature engineering structure and a manufacturing method of the high-strength steel plate, and belongs to the technical field of low-carbon microalloyed steel production. Optimized steelmaking, heating, rolling, controlled cooling and straightening processes are adopted, and finally the problems of low toughness, high yield ratio, low flaw detection qualification rate and plate shape unevenness of the 690MPa-grade hot-rolled steel plate with the thickness of 10-40mm produced by an online cooling process are solved.

The utility model relates to the technical field of refrigeration and low-temperature engineering, and provides a low-temperature fluid circulation system which comprises a cold source, a thermal load and a magnetic driver, the thermal load is connected with the cold source through a circulation pipeline, and the circulation pipeline is filled with low-temperature fluid media; the magnetic driver comprises an impeller, and the impeller is arranged in the circulating pipeline between the thermal load and the cold source and used for driving the low-temperature fluid medium to circularly flow in the circulating pipeline through rotation; according to the utility model, the circulating pipeline is arranged between the heat load and the cold source, and the heat transfer mode between the cold source and the load is changed from solid heat conduction in the prior art to convective heat transfer through circulating flow of low-temperature fluid in the circulating pipeline, so that the heat transfer effect is effectively enhanced; the cold energy is transferred to the heat load or the heat of the heat load is transferred to the cold source, so that the effect of reducing the temperature of the heat load is achieved, and the device is particularly suitable for occasions where the cold energy of the cold source is very small and long-distance cold energy transportation is needed below a liquid hydrogen temperature area.

This invention belongs to the field of cryogenic engineering research and application technology, specifically relating to a vacuum socket device for receiving and transferring liquid hydrogen. The device includes a sealing tube I, an outer tube I, a connecting tube I, an integral flange, a sealing tube II, a connecting tube II, an inner tube, a flange shoulder, an outer tube II, a flange ring, a threaded seal, a sealing ring, and a gasket. The protruding structure of the threaded seal, the annular gap B, and the large-diameter end face of the flange shoulder form chamber A. The annular gap A and the shoulder of the sealing tube II form chamber B. Chamber B communicates with an evacuation port machined on the side wall of the outer tube II. When a vacuum is drawn through the evacuation port, chamber B forms a vacuum chamber. The sealed chamber A is located outside the vacuum chamber B. This double-layered chamber enhances the effect of preventing heat exchange between liquid hydrogen and the external environment, significantly reducing evaporation loss of liquid hydrogen during transfer and reception. The socket joint has a flange connection structure, facilitating disassembly and improving the adaptability of the equipment.

The invention relates to the technical field of plastic composite materials, in particular to a high-impact-resistance and low-temperature-resistance engineering plastic composite material and a preparation process thereof, and the high-impact-resistance and low-temperature-resistance engineering plastic composite material is prepared from the following raw materials in parts by weight: 55-85 parts of a double-resin blending system; 20 to 40 parts of a toughening system; 20 to 35 parts of a reinforcing system; 0.3 to 0.6 part of a main antioxidant; 0.2 to 0.4 part of an auxiliary antioxidant; 0.8 to 1.5 parts of an internal lubricant; 0.5 to 1.2 parts of an external lubricant; 1-3 parts of an ultraviolet screening agent; and 0.3 to 0.8 part of a migration type lubricant. According to the invention, through the synergistic effect of a double-resin blending system, the balance between excellent toughness and strength is maintained at a low temperature, through the nanoscale dispersion and low-temperature compatibility design of the specific flexibilizer, the impact resistance of the material in an extremely cold environment is significantly improved, and through the reinforcement refining treatment and interface strengthening technology, the impact resistance of the material in an extremely cold environment is greatly improved. The low-temperature crack growth is effectively inhibited, the high modulus effect is maintained, the problems that the impact strength is greatly reduced and the brittleness is increased in a low-temperature environment in the traditional engineering plastic are solved, and the application scene is wider.

The present invention discloses a cryogenic separation of propane dehydrogenation to propylene products and a hydrogen liquefaction co-production system and method, belonging to the technical field of refrigeration and cryogenic engineering. The system includes an atmospheric cold box, a vacuum cold box, a hydrogen compression unit, and a mixed refrigerant compression unit. The propane raw material is vaporized in the atmospheric cold box and then sent to the downstream cracking unit. The cracking products from the cracking unit are cryogenically separated in the atmospheric cold box to obtain high-purity propane / propylene products and hydrogen-rich gas. The hydrogen-rich gas is further separated, purified, and cooled in the vacuum cold box to obtain high-purity liquid hydrogen. The mixed refrigerant cycle and the hydrogen refrigeration cycle respectively provide cooling capacity for the atmospheric cold box and the vacuum cold box. The system couples the propane dehydrogenation cryogenic separation process and the hydrogen liquefaction process to achieve the efficient and energy-saving production of high-purity liquid hydrogen. The specific energy consumption of the system does not exceed 15.4 kWh / kg of liquid hydrogen, reducing the total energy consumption of the two independent processes by about 30%. The system has wide applicability and can flexibly adapt to different cracking processes, improving the single-pass conversion rate of the cracking process.

A cascade refrigeration natural gas liquefaction system and process, which relate to the technical field of refrigeration and cryogenic engineering. The process may include an ethane refrigeration cycle and a mixed refrigerant refrigeration cycle. Refrigerants according to the present disclosure may include propane, ethane and a mixed refrigerant that may be composed of nitrogen, methane and ethane. Except for nitrogen supplied from public utilities, the refrigerants may be sourced from the natural gas itself. The comprehensive energy consumption of liquefaction per unit according to the present disclosure may be lower than the propane precooling mixed refrigerant process and the conventional cascade process. Although it may be slightly higher than that of the dual mixed refrigerant process in winter working condition, the energy consumption of the dual mixed refrigerant process is exceedingly high in summer, and the total energy consumption of the process of the present disclosure is still low comprehensively.

The invention relates to the technical field of industrial process control and low-temperature engineering, in particular to a phase change anti-freezing control method based on state equation constraint, and overcomes the defects of response lag and non-intrinsic safety of traditional temperature feedback control under a cryogenic transient working condition. The method comprises the steps that the pressure of a refrigerant containing cavity is collected in real time, and the unmeasurable hysteresis freezing risk is mapped into a saturation temperature boundary capable of being instantaneously observed through a thermodynamic state equation (EOS); and constructing a freezing margin index, and when the index is in contact with a safety threshold value, triggering the hard constraint override logic with the highest priority, and forcibly adjusting the gas phase resistance so as to increase the phase change backpressure. According to the method, the sound velocity transfer characteristic of pressure waves is utilized, a physical anti-freezing barrier is established within the millisecond level, relying on postmortem detection and melting remediation in the prior art is not needed, and zero-lag prevention and multivariable decoupling control in the cryogenic heat exchange process are achieved.