243 results about "Liquid helium" patented technology

The invention discloses a conduction cooling type superconducting isochronous cyclotron, and belongs to the technical field of superconducting isochronous cyclotrons. Comprising an accelerator main support, the accelerator main support is integrally of a base frame structure composed of a plurality of vertical supports, vertically-arranged hydraulic lifting systems are further fixedly installed on the side walls of each set of vertical supports, and a first magnet yoke is fixedly installed at the top of the accelerator main support; a refrigerating machine direct conduction cooling technology is adopted, a traditional liquid helium soaking cooling system is replaced, and the problem that a superconducting cyclotron depends on a complex liquid helium refrigeration unit and is redundant in structure is solved. While the magnetic field intensity is maintained, heavy parts such as a liquid helium pool, a recondenser and a multi-layer heat insulation pipeline are completely abandoned, so that the system height and the sealing complexity are remarkably reduced, and high operation and maintenance cost caused by dependence of liquid helium resources is also avoided.

The utility model relates to a low-temperature vacuum heat insulation structure for a liquid helium Dewar tank, which belongs to the technical field of heat insulation and comprises an inner container consisting of a lower seal head at the bottom, a barrel in the middle and an upper seal head at the top, a neck tube is arranged at the upper seal head, a plurality of fins are arranged on the neck tube, and the fins are arranged in the inner container. The outer side of the inner container is alternately wrapped with a plurality of heat insulation blocking units and flexible anti-radiation cold shield units from inside to outside, the number of the heat insulation blocking units is one more than that of the flexible anti-radiation cold shield units, and the number of the flexible anti-radiation cold shield units is consistent with that of the fins. And the flexible anti-radiation cold shield units are in one-to-one correspondence with the fins and cover the outer sides of the corresponding fins. The flexible anti-radiation cold shield unit is used as a heat conduction gap bridge between the fins and the cylinder body, the temperature of the middle part of the heat insulation material is reduced through the gas-phase cooling capacity at the neck pipe, and the heat insulation effect is good.

The invention belongs to the field of magnetic materials, and particularly discloses europium-based silicate as well as a preparation method and application thereof. The general chemical formula of the europium-based silicate is Eu2SiO4, and the europium-based silicate is subjected to secondary magnetic phase change from a paramagnetic state to a ferromagnetic state at the magnetic phase change temperature of 5.8 K; and at the temperature of 5.5 K, when the magnetic field change is 0-2T, the maximum magnetic entropy change is greater than 10J. Kg <-1 >. K <-1 >. The europium-based silicate disclosed by the invention generates paramagnetic to ferromagnetic phase change near the liquid helium temperature, is accompanied by a low-magnetic-field giant magnetothermal effect near the magnetic phase change temperature, shows large magnetic entropy change and refrigerating capacity near the liquid helium temperature, and has a wide application prospect in the field of magnetic refrigeration in a liquid helium temperature region.

The invention discloses an inverted 2K liquid-helium-free low-temperature probe station based on a GM refrigerating machine. The inverted 2K liquid-helium-free low-temperature probe station comprises a 2K plate, a vacuum cavity, a refrigerating system and a heat insulation assembly. The refrigerating system comprises a GM refrigerating machine, a thermal switch and a helium circulating system, and the GM refrigerating machine adopts a two-stage GM refrigerating machine, is inverted and extends into the vacuum cavity; the helium circulation system comprises a superflow helium pool installed at the bottom of the 2K plate, the helium circulation system takes away the cooling capacity of the refrigerating machine through circulation helium, the temperature is further reduced through throttling cooling and evacuation pressure reduction, and a 2K low-temperature environment is achieved at the 2K plate. The thermal switch provides cooling capacity for the 2K plate during initial operation so as to realize cooling; the heat insulation assembly comprises multiple stages of heat radiation screens and is used for reducing radiation heat leakage to the vacuum cavity. The 2K plate layout with the 2K plate temperature lower than 2K and the upward direction can be provided, and extra refrigerating working media such as liquid helium are not consumed.

The invention provides a high-sensitivity superconducting magnetic detection device and method based on an NV color center under high pressure and low temperature. The high-sensitivity superconducting magnetic detection device comprises a microwave emission module, an optical excitation module, an imaging module, a fluorescence collection module, a data collection and control module, a diamond anvil cell, a low-temperature test module and a magnet module. The method has the beneficial effects that the diamond injected with the NV color center serves as the anvil cell of the diamond anvil cell, and high-pressure and low-temperature conditions are synchronously obtained in liquid helium and liquid nitrogen temperature zones; according to the invention, in-situ pressure measurement can be realized under high pressure, and ruby or Raman standard pressure is not needed; a sample is placed in the diamond anvil cell, the diamond anvil cell is placed in the low-temperature cavity, the lowest temperature of 4K and in-situ pressurization can be realized by using the low-temperature test module, and the quality of a microwave signal transmitted by the low-temperature semi-steel cable is higher and the loss is smaller by using the low-temperature semi-steel cable. And the superconducting property of the material at low temperature and high pressure is quantitatively tested under the condition of high integration.

The invention relates to the technical field of superconducting magnets, in particular to a superconducting magnet cold energy recovery system. A superconducting magnet cold energy recovery system comprises a shell which is a Dewar container, and is characterized in that a cold shield is arranged in the shell, and a steel pipe disc is arranged on the outer side of the cold shield; a cold shield tank is arranged in the cold shield, one side of the top of the cold shield tank is connected with a liquid helium inlet, and the other side of the top of the cold shield tank is connected with a cooling system outlet; a superconducting coil is arranged in the cold shield tank, and the two ends of the superconducting coil are connected with current wires respectively. Compared with the prior art, the superconducting magnet cold energy recovery system provided by the invention has the advantages that helium entering the current lead is pre-cooled through heat exchange between the low-temperature helium inlet of the current lead and the low-temperature helium outlet of the superconducting coil, so that low-temperature helium cold energy from the superconducting coil is recovered.

The utility model discloses a helium cooler for a liquid helium temperature zone. The helium cooler comprises a vacuum cavity and a vacuum flange cover fixed above the vacuum cavity in a sealed mode. A cold shield, a liquid helium cavity, a liquid nitrogen cavity and a liquid helium cavity suspender are arranged in the vacuum cavity; the liquid helium cavity and the liquid nitrogen cavity are both arranged in the cold shield, and the liquid nitrogen cavity is located above the liquid helium cavity. The upper end of the liquid helium cavity suspender is fixed with the vacuum flange cover, the lower end of the liquid helium cavity suspender is fixed with the liquid helium cavity, and the middle section of the liquid helium cavity suspender is fixed with the inner side of the cold shield; a heat exchange coil pipe and a liquid level meter are installed in the liquid helium cavity, a cold shield coil pipe is installed on the outer side of the cold shield, and the cold shield coil pipe is connected with the liquid nitrogen cavity; the vacuum flange cover is provided with a heat exchange coil inlet pipe and a heat exchange coil outlet pipe, and the heat coil inlet pipe and the heat exchange coil outlet pipe are connected with the two ends of the heat exchange coil respectively. According to the utility model, the helium working medium in other states is cooled to a liquid helium temperature area by using liquid helium, so that the low heat leakage is ensured, and the structural strength is good.

The invention belongs to the technical field of magnetic refrigeration, and particularly discloses a rare earth europium-based zirconate magnetic refrigeration material and a preparation method and application thereof. The general chemical formula of the rare earth europium-based zirconate magnetic refrigeration material is (Eu1-xMx) (Zr1-yNy) O3, M is any one of Ca, Sr or Ba, N is any one of Nb, Ta, Ti or Hf, x is more than or equal to 0 and less than or equal to 0.5, y is more than or equal to 0 and less than or equal to 0.5, and the magnetic phase transition temperature of the rare earth europium-based zirconate magnetic refrigeration material is less than 10K. The magnetic refrigeration material shows excellent magnetocaloric performance near the liquid helium temperature, and is expected to be applied to the liquid helium temperature zone magnetic refrigeration technology; and the preparation method is simple in process, safe and environment-friendly, and can be applied to industrial production.

The invention discloses a high-magnetic-field and high-uniformity superconducting magnet system for nuclear magnetic resonance, belongs to the technical field of nuclear magnetic resonance, and solves the problem of how to design a high-magnetic-field-intensity and high-uniformity superconducting magnet system. A high-field area in the magnet is a coil using a niobium-tin superconducting wire, and a low-field area in the magnet uses a coil using a niobium-titanium superconducting wire; the main coils are connected in series to work together, and can generate an effective central magnetic field intensity of 18.8 T when operating at a liquid helium temperature; the design uniformity of a central magnetic field can be superior to 0.01 ppm in a spherical range with the diameter of 1cm; the main magnetic field coil can shield more than 90% of external electromagnetic interference; the shielding coil can effectively control the size of a stray field of a magnet system, and a 5Gs line stray field can be limited in a 1.5 m ellipsoid and a 2.5 m ellipsoid in the radial direction and the axial direction respectively. The method is suitable for a nuclear magnetic resonance spectrometer, animal imaging, Fourier transform ion cyclotron resonance and other scenes.

The invention relates to a coarse helium purification and liquefaction circulation system and method based on low-temperature rectification, and relates to the technical field of low-temperature refrigeration and the technical field of chemical separation. The system comprises a crude helium liquefying unit, a pure helium circulating liquefying unit and a cooling capacity providing unit. The crude helium liquefying unit comprises a crude helium pipeline, a 77K low-temperature adsorber, a multi-stage turbo expander, a multi-stage heat exchanger, a gas-liquid separator, a 20K adsorber, a throttle valve and a liquid helium tank, and is used for liquefying and purifying crude helium; the pure helium circulating liquefaction unit comprises a pure helium pipeline, a multi-stage turbo expander, a reflux compressor, a throttle valve and the like, and is used for liquefying refluxed pure helium; the heat exchange unit comprises a liquid nitrogen pipeline, a backflow pipeline, a multi-stage heat exchanger and the like and is used for providing cooling capacity. By adopting the technical scheme of purifying and liquefying the crude helium and refluxing and liquefying the pure helium, the crude helium extracted from the natural gas through low-temperature condensation can be purified and then liquefied, the energy consumption is low, the operation temperature is flexible, the recovery rate is high, and the low-temperature rectified crude helium can be directly treated.

The invention relates to the technical field of valve performance testing, in particular to a system and method for testing the reliability of a valve in a liquid hydrogen temperature zone, and a low-temperature container comprises a liquid nitrogen low-temperature tank and a liquid helium cooling chamber; the liquid nitrogen low-temperature tank is selectively communicated with the liquid nitrogen storage device; the liquid helium cooling chamber is provided with a closed cavity, is positioned in the liquid nitrogen low-temperature tank and is selectively communicated with the liquid helium storage device; the test main path comprises an air inlet branch and an air outlet branch; the gas inlet branch introduces helium into the valve to be tested; the gas outlet branch is used for judging the sealing condition of the to-be-tested valve; the temperature measuring assembly comprises a second temperature sensor arranged on the valve to be measured and is used for measuring the temperature of the valve to be measured. The device can completely and truly simulate the real working condition of the low-temperature valve, and meets the complex test requirements of the liquid hydrogen valve. The liquid helium cooling chamber and the liquid nitrogen low-temperature tank provide double cold insulation effects for the valve to be tested, the heat influence of the temperature of the inner wall surface of the liquid helium cooling chamber on the liquid helium can be reduced, more efficient utilization of the liquid helium is further realized, and the test cost is reduced.

The invention relates to a storage cryostat (2) for liquid helium (7), suitable for transferring liquid helium (7) from the storage cryostat (2) into an application cryostat (3), wherein the storage cryostat (2) comprises: - a vacuum-insulated helium vessel (6) for liquid helium (7), the helium vessel (6) having a vertical height HHB that can be filled with liquid helium (7), - a transfer line (4) for liquid helium (7), having an inlet opening (20) which opens into a lower region of the helium vessel (6), in particular into a lower fifth of the helium vessel (6), and - a convection-suppression system (9) which is arranged within the helium vessel (6) and impedes vertical convection of liquid helium (7) in the helium vessel (6), characterised in that the convection-suppression system (9) is formed in the helium vessel (6) over a height interval (IKS) with a vertical height HKS, where HKS ≥ 0.50 × HHB, and in that the convection-suppression system (9) impedes the vertical convection of liquid helium (7) in the helium vessel (6) over the region of the height interval (IKS) of the convection-suppression system (9). The invention provides a storage cryostat that enables simple and rapid transfer of liquid helium from the storage cryostat into the application cryostat, with minimised helium losses.

The invention relates to the technical field of material mechanical property testing, and provides an ultralow-temperature slow strain mechanical tensile test platform which comprises a vacuum Dewar unit, a liquid helium temperature control unit, a slow strain tensile unit, a measuring unit and a control unit, the vacuum Dewar unit comprises a vacuum Dewar body and is used for providing a closed low-temperature test environment; the liquid helium temperature control unit comprises a direct injection module and a recovery module, the direct injection module is used for directly injecting liquid helium to the gauge length section of the sample for cooling, and the recovery module is used for recovering and recycling unevaporated liquid helium; the slow strain stretching unit is used for stretching a sample arranged in the vacuum Dewar body at a low strain rate; the measuring unit is arranged in the vacuum Dewar body and is used for monitoring the temperature, the force value and the strain data of the sample in real time. Liquid helium is used as a cold source, the liquid helium is directly aligned to the gauge length section of the sample through the direct injection module, and compared with a traditional liquid helium steam natural convection heat exchange mode, the heat exchange coefficient is increased, and automatic precise temperature control is achieved.

The invention relates to the technical field of fusion devices, and discloses a composite multi-channel multi-medium pipeline for a fusion device.The composite multi-channel multi-medium pipeline comprises a heat shielding part, a vacuum pipeline, a liquid helium conveying assembly and a first gas helium conveying assembly, and the interior of the heat shielding part is hollow to form a first containing space; the vacuum pipeline sleeves the periphery of the heat shielding part, the vacuum pipeline and the heat shielding part are arranged at an interval, a second accommodating space is formed between the heat shielding part and the vacuum pipeline, and the heat shielding part is used for shielding heat transfer between the first accommodating space and the second accommodating space; the liquid helium conveying assembly is used for conveying liquid helium and arranged in the first containing space to be fixedly connected with the heat shielding piece. The first gaseous helium conveying assembly is used for conveying first gaseous helium and arranged in the second containing space to be fixedly connected with the heat shielding piece and the vacuum pipeline. The composite multi-channel multi-medium pipeline for the fusion device is not only suitable for transmission of different media, but also capable of avoiding heat transfer between the different media.

The present invention discloses a method for preparing a rare earth-based multivalent manganese oxide low-temperature magnetic refrigeration material by a molten salt method, which relates to the technical field of magnetic functional materials. The steps are as follows: Weigh manganese dioxide powder and rare earth oxide powder according to the stoichiometric ratio of the rare earth-based multivalent manganese oxide, mix them with sodium chloride, and grind to obtain a mixed powder; sinter the mixed powder at a high temperature and cool it to room temperature with the furnace to obtain a sintered powder; wash the sintered powder with water to remove sodium chloride and dry it to obtain the product. The process of the present invention is simple and low in cost. The prepared rare earth-based multivalent manganese oxide has a large magnetocaloric effect near the liquid helium temperature range. Among them, the REMn2O5-type rare earth-based multivalent manganese oxide has an isothermal magnetic entropy change of up to 12.61 J kg ‑1 K ‑1 , and the relative cooling power RCP is up to 338 J kg ‑1 . It can be used as a low-temperature magnetic refrigeration material in low-temperature engineering, aerospace, medical devices and other fields.

The invention relates to the technical field of low-temperature system integration, in particular to a helium liquefaction and recondensation chip test low-temperature system which comprises a liquid helium test cavity, a pulse tube refrigerating machine and a helium tank, the pulse tube refrigerating machine comprises a refrigerating machine compressor, a refrigerating machine cold head and a refrigerating machine cold screen, and the refrigerating machine cold head is connected with a condensation heat exchanger. The liquid helium testing cavity and the condensing heat exchanger are located in the refrigerating machine cold screen, the refrigerating machine cold head is communicated with the liquid helium testing cavity through a cold helium return pipeline, and the condensing heat exchanger is communicated with the liquid helium testing cavity through a liquid helium return pipeline. The helium tank is connected with the refrigerator cold head through a pipeline. The liquid helium testing cavity is used for containing liquid helium to provide a soaking testing environment, the problem of electromagnetic interference is avoided, cold helium evaporated in the liquid helium testing cavity flows back into the liquid helium testing cavity from the liquid helium backflow pipeline after being condensed through the condensation heat exchanger, and zero evaporation of the liquid helium in the superconducting chip testing process is achieved. And long-term test requirements of large-scale superconducting chips can be met.

A circulating refrigeration system without liquid helium consumption. The system comprises: a liquid-helium-free refrigerating machine (40); a copper shielding tube (10), one end of the copper shielding tube (10) being connected to a shielding cylinder (5) of the liquid-helium-free refrigerating machine (40), and a first-stage cold head connector (11) and a second-stage cold head connector (13) being provided at the other end of the copper shielding tube (10); a first-stage cold shield, which is connected to the first-stage cold head connector (11) by means of a copper braid and is arranged on the outer ring of a μ metal cover; the μ metal cover, which is connected to the first-stage cold head connector (11) by means of the copper braid and is connected to the first-stage cold shield by means of a first-stage cold shield copper braid, wherein the μ metal cover, as a fixing ring, is in vacuum connection with a lower pole piece of an electron microscope, and the μ metal cover is connected to a Z-axis piezoelectric ceramic holder in a sample chamber (8) by means of a thermally insulating gasket; and a sample stage fixing member (28), which is connected to the second-stage cold head connector (13) by means of the copper braid. The present application can achieve a required liquid-helium temperature range environment for a long time, thereby greatly reducing the experiment cost, reducing mechanical vibrations, improving the transverse resolution, and thus realizing an ultrahigh resolution of an electron microscope.

According to the light helium storage spray pipe with the integrated efficiency of efficiency increasing, pushing changing, phase change heat prevention and infrared stealth, by means of the high phase change latent heat characteristic of liquid helium, the liquid helium is directly injected into the spray pipe to be mixed with high-temperature fuel gas; the temperature of fuel gas and thermal stress borne by a spray pipe material are remarkably reduced through phase change heat absorption, heat convection and gas film cooling, efficient thermal protection is achieved, the infrared radiation intensity of exhaust plume is effectively restrained, and the infrared stealth effect is achieved; the characteristic that helium is small in molecular weight is utilized, the expansion power capability of mixed gas and the propulsive efficiency and specific impulse of the engine are improved, meanwhile, through real-time regulation and control of helium injection flow, thrust adjustment to a certain degree can be achieved, and the maneuverability of the engine is enhanced. According to the designed composite interlayer structure, the thickness of the wall face of the spray pipe can be greatly reduced, the structural strength of the spray pipe is improved, and then the overall mass of an engine is reduced.

The invention discloses a helium magnetocaloric phase change circulation power device which comprises a liquid helium tank, a plunger pump, a helium compressor, a heat exchange tank, a first surge tank, a countercurrent heat exchanger, a second surge tank and a turbo expander. Liquid helium and gas helium are stored in the liquid helium tank; the plunger pump is used for pressurizing liquid helium in the liquid helium tank to set pressure; the heat exchange tank internally comprises a magnetocaloric working medium, a rotating magnetic field, a cold source helium heat exchange pipeline and a heat source helium heat exchange pipeline, and the magnetocaloric working medium based on the magnetocaloric inverse heat effect is used as a medium, so that a heat source and cold and heat source helium are subjected to inverse heat exchange; the first surge tank and the second surge tank are used for stabilizing the inlet and outlet air pressure of the expansion machine so as to stabilize the working efficiency of the expansion machine; the countercurrent heat exchanger is used for carrying out heat exchange on high-pressure helium output by the first surge tank and a heat exchange medium for absorbing environmental heat energy; the expansion machine is used for converting heat energy of gas into mechanical energy and then converting the mechanical energy into electric energy through the generator, and recycling of environment low-temperature heat energy is achieved.

The invention relates to the technical field of thermophysical property measurement, in particular to a high-precision liquid helium temperature zone material thermal conductivity measurement device and method. A low-temperature refrigeration module is used for generating an ultralow-temperature measurement condition in a set temperature range; the vacuum heat insulation module comprises an anti-radiation secondary cold shield, a multi-layer heat insulation primary cold shield and a vacuum cavity which are sequentially arranged in the outer side space of the sample; the pressure-bearing sample table module comprises an oxygen-free copper clamp used for fixing a sample, a thermal damping fin is arranged in the oxygen-free copper clamp and abuts against a cold head temperature adjusting heater, the cold head temperature adjusting heater is located on the upper surface of a pressure-bearing cold disc, and the lower bottom face of the pressure-bearing cold disc is connected with a solid polytetrafluoroethylene supporting rod through a solid epoxy resin supporting rod. The lower bottom face of the solid polytetrafluoroethylene supporting rod is connected to the stainless steel supporting rod. The thickness measurement and control module controls and measures the thickness between sample interfaces by utilizing a servo linear motor and a transmission rod; the temperature measurement and control module is used for acquiring and controlling the temperature at the axis of the heat flow meter.

The invention relates to the technical field of low-temperature imaging, in particular to a low-temperature microscopic imaging system. The low-temperature microscopic imaging system comprises a helium medium circulation assembly, a cold transfer assembly and an imaging assembly, liquid helium is stored in the helium medium circulation assembly, the cold transfer assembly is connected with the helium medium circulation assembly, and the cold transfer assembly comprises a first cold transfer unit and a second cold transfer unit for liquid helium to flow; the imaging assembly comprises a sample table, a support and a low-temperature imaging piece, the support is connected with the sample table, and the low-temperature imaging piece is connected with the support; one end of the first cold transfer unit is communicated with the helium medium circulating assembly, the other end of the first cold transfer unit is communicated with the sample table, a throttle valve is arranged in the first cold transfer unit, one end of the second cold transfer unit is connected with the helium medium circulating assembly, and the other end of the second cold transfer unit is connected with the sample table. The device has the advantages that pre-cooling can be performed through the second cold transfer unit before a formal experiment, then cryogenic cooling is achieved through the first cold transfer unit, and the cooling efficiency is high.

A device (101) for transferring liquid helium (14) into an application cryostat (102), comprising: a storage dewar (1); a transfer line (9) comprising a first transfer line end (9a) in the storage dewar (1) and a second transfer line end (9b) for insertion into an application cryostat (102); a device (31) for generating a pressure difference between the storage dewar (1) and the application cryostat (102); is characterized by: a condensation heat exchanger (17) for condensing helium gas (12) to liquid helium (11), for insertion into the application cryostat (102); a cryocooler (29) for cooling the condensation heat exchanger (17); and a control device (8) with a measuring input (18a) for a pressure sensor (18) for measuring the gas pressure in the application cryostat (102) and a control output. (31a) for the device (31) for generating a pressure difference, wherein the control device (8) is programmed toThe device (31) is controlled to generate a pressure difference such that the volume of liquid helium (14) transferred per unit time through the transfer line (9) is approximately equal to the volume change of the helium that condenses from helium gas (12) to liquid helium (11) per unit time at the condensation heat exchanger (17). The device minimizes helium losses during the transfer of liquid helium in a simple manner.

The invention discloses a preparation method of a superconducting nanowire single-photon detector capable of keeping high detection efficiency in a liquid helium temperature region. The preparation method comprises the following steps: adopting a double-layer substrate formed by silicon oxide and silicon; the method comprises the following steps: growing a niobium nitride film on a silicon oxide surface of a substrate through radio frequency magnetron sputtering to serve as a buffer layer, growing a niobium nitride film through direct current magnetron sputtering, and accurately measuring and controlling the thickness through XRR; the method comprises the following steps: preparing a double-line parallel nanowire structure in a manner of exposing PMMA A4 electron beam glue by electron beams, and transferring a nanowire pattern to a niobium nitride film in a reactive ion etching manner; the method comprises the following steps of: removing photoresist above a region needing to be etched on a silicon oxide surface of a substrate in a manner of exposing the AZ4620 photoresist through ultraviolet laser direct writing, and then etching silicon oxide and silicon from the silicon oxide surface of a device through reactive ion etching to prepare a suspension bridge structure. The high detection efficiency of the device is ensured while the working temperature of the device is greatly improved.

The invention discloses a double-vacuum-layer horizontal liquid helium storage tank which is characterized by comprising an inner container, a supporting wall, an outer tank, a first flange structure and a second flange structure. The outer tank, the supporting wall and the inner container are sequentially arranged from outside to inside, a first vacuum layer is formed between the inner container and the supporting wall, and a second vacuum layer is formed between the supporting wall and the outer tank; the first flange structure is fixedly connected with the inner container and the supporting wall. The second flange structure is fixedly connected with the supporting wall and the outer tank; a heat insulation reflecting layer and a reinforcing layer are sequentially arranged on the outer wall of the inner container from inside to outside; according to the storage tank, on the premise that the storage amount of the liquid helium storage tank is guaranteed, heat radiation conducted from the interior is isolated and reflected, cold leakage caused by heat radiation and convection is effectively reduced, structural reinforcement is conducted on the inner container which is prone to failure, the safety of equipment during operation is improved, and the working efficiency of the equipment is improved.

The invention discloses a liquid helium ultralow-temperature impact system based on vacuum and a use method thereof, and belongs to the technical field of liquid helium ultralow-temperature impact mechanical property testing equipment, and the liquid helium ultralow-temperature impact system based on vacuum comprises an ultralow-temperature vacuum experiment cavity, a vacuum unit, a liquid helium supply device, an impact device and a strain acquisition device. The device is clear in structure and simple in principle; liquid helium is adopted for refrigeration, so that the temperature in the experiment cavity can reach an ultralow temperature environment, and the device can be used for impact loading mechanical property testing of different samples in a complex stress state in the ultralow temperature environment.

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 liquid helium tank protection device and a protection method thereof, and relates to the technical field of liquid helium storage tanks, the liquid helium tank protection device comprises a tank body, a folding shielding piece is arranged on a sleeving ring, and a universal buffering piece connected with the tank body is arranged on the inner side of a connecting clamping ring. By arranging the universal buffer part, when liquid helium in the tank body impacts an inner container of the tank body due to inertia, the tank body pulls a damping spring through a first limiting sleeve and a first spherical block, in this way, the tank body can be buffered, the tank body is protected, an electromagnetic valve is closed by pressing a pressing switch, and the safety of the tank body is improved. In this way, the water solution in the sleeve loses the flowing space, the pressing rod cannot move relative to the sleeve, the tank body is fixed and prevented from shaking in the using process, meanwhile, due to the fact that the discharging head is connected with the sleeving ring through the annular ball shaft, the tank body can be in the vertical state all the time under the action of gravity, and the water solution in the tank body can be discharged. Therefore, convenience is provided for the use of subsequent equipment.

According to the refrigerating system of the magneto-optical measuring device and the control method of the refrigerating system, a GM refrigerating machine is externally arranged, a helium circulation throttling expansion structure is utilized, and ultralow-temperature liquid helium at the temperature of 2K or below is obtained through the GM refrigerating machine under the condition that a large amount of liquid helium is not consumed; the GM refrigerating machine and the optical strong magnetic thermostat are connected through the low-loss infusion tube, and the low-loss infusion tube is fixed through the fixing frame, so that vibration transmitted by the GM refrigerating machine part is filtered out, and the experiment conditions of ultralow temperature, strong magnetic field and ultralow vibration are achieved; meanwhile, after entering the optical strong magnetic thermostat, the cooled liquid helium is divided into two parts which do not influence each other and is respectively used for cooling the sample area and the magnet cold shield, so that the cooling efficiency is improved, and the consumption of the liquid helium is reduced.

The invention discloses a Siemens PLC-based liquid helium Dewar liquid volume calculation method and system, which are applied to the technical field of low-temperature control, and the method comprises the steps: obtaining the data of a liquid helium Dewar tank capacity meter and the data of a liquid level meter; calculating based on the data of the liquid helium Dewar tank capacity meter and the data of the liquid level meter to obtain the liquid helium Dewar liquid volume; and the liquid level meter data and the liquid volume of the liquid helium Dewar are displayed through an upper computer.