A low-temperature circulating pump and a low-temperature circulating refrigeration system

Abstract

The application discloses a low-temperature circulating pump and a low-temperature circulating refrigeration system. The low-temperature circulating pump comprises a storage part, a pipeline and a magnet. The storage part comprises a first storage part and a second storage part connected in series by superfluid, and the first storage part and the second storage part are respectively a paramagnetic salt storage part and an antiferromagnetic salt storage part. The pipeline is connected to both ends of the storage part to move the superfluid along the pipeline to realize heat exchange. The magnet is arranged outside the first storage part and the second storage part to provide a changing magnetic field for the first storage part and the second storage part, and a temperature difference is formed between the first storage part and the second storage part through the magnetocaloric effect to realize the circulating flow of the superfluid in the low-temperature circulating pump. The superfluid is circulated through the magnetocaloric effect of the paramagnetic salt and the antiferromagnetic salt, and the superfluid always remains in a liquid state during the process, so that the large-flow and continuous refrigeration circulation is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultra-low temperature refrigeration, and particularly relates to a low-temperature circulating pump and a low-temperature circulating refrigeration system. BACKGROUND

[0002] An ultra-low temperature temperature zone refers to a low-temperature environment with a temperature lower than 1K. Basic physical research can be carried out at the ultra-low temperature, and an extreme low-temperature environment can be provided for space exploration and quantum computing. In the fields of high-energy physics, superconductivity, aerospace and atomic energy science, there is a demand for ultra-low temperature refrigeration technology. A superfluid is a state of matter, which is often formed under ultra-low temperature conditions. The superfluid has a zero internal friction coefficient, and thus can flow rapidly along a flow channel, so that the superfluid can be used as a refrigeration working medium in an ultra-low temperature refrigeration system to realize ultra-low temperature refrigeration and provide an ultra-low temperature system.

[0003] The liquefaction temperature of helium (He) is 4.2K under one atmosphere, and the internal friction coefficient of liquid helium is zero at 2.17K to form He II. At this time, He II contains ordinary fluid He and superfluid He, and can be used as a refrigeration working medium in an ultra-low temperature refrigeration system. Continuous ultra-low temperature refrigeration using He as a refrigeration working medium needs to use an oil-free dry pump to drive the circulation of superfluid helium. However, this design requires the superfluid helium to be warmed up to room temperature and then enter a cold finger through multiple stages of pre-cooling, which consumes a large amount of energy. In addition, the gas circuit from the low-temperature cavity to room temperature has a large volume, which is not conducive to the realization of a compact ultra-low temperature system. A refrigeration system in which the gas circuit does not pass through room temperature is referred to as a low-temperature circulating refrigeration system. In the prior art, an adsorption pump and a condensing pump are used to realize low-temperature circulating refrigeration. The condensing pump collects and liquefies gaseous helium at a low temperature, and then makes the liquid helium re-enter the refrigeration cycle. However, the condensing pump needs to continuously consume low-temperature cold energy for adiabatic demagnetization when working, and thus cannot realize a large-flow and continuous refrigeration cycle after a period of work. The adsorption pump uses an adsorbent to adsorb helium to form a negative pressure, so as to realize the circulation of helium in the pump. However, the adsorption capacity of existing adsorbents such as activated carbon for helium is weak, and the adsorbent also needs to be reactivated after a period of work, so that a large-flow and continuous refrigeration cycle cannot be realized.

[0004] Therefore, the prior art still needs to be improved and developed. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a low-temperature circulating pump and a low-temperature circulating refrigeration system, which aims to solve the problem that the use of He as an ultra-low temperature refrigeration working medium in the prior art cannot realize a large-flow and continuous refrigeration cycle.

[0006] The first aspect of the present application provides a low-temperature circulating pump, comprising:

[0007] a storage part comprising a first storage part and a second storage part connected in series by a super-leak, for storing superfluid, and the first storage part and the second storage part are paramagnetic salt storage part and antiferromagnetic salt storage part respectively;

[0008] a pipe connecting two ends of the storage part for the superfluid to move along the pipe to realize heat exchange;

[0009] a magnet arranged outside the first storage part and the second storage part, providing a varying magnetic field for the first storage part and the second storage part, forming a temperature difference between the first storage part and the second storage part through the magnetocaloric effect, realizing the circulating flow of the superfluid in the low-temperature circulating pump.

[0010] In an embodiment, the superfluid is 3 He and 4 superfluid state in He mixture 4 He or pure 4 superfluid state in He 4 He.

[0011] In an embodiment, the first storage part and the second storage part are cylindrical structures.

[0012] In an embodiment, one of the first storage part and the second storage part stores paramagnetic salt particles and the superfluid, forming the paramagnetic salt storage part, and the other stores antiferromagnetic salt particles and the superfluid, forming the antiferromagnetic salt storage part.

[0013] In an embodiment, the magnet is a superconducting magnetic coil surrounding the first storage part and the second storage part.

[0014] In an embodiment, the magnet provides a linearly varying varying magnetic field to the first storage part and the second storage part.

[0015] In an embodiment, the super-leak is a material with micro-nano pores.

[0016] In an embodiment, the pipe is connected with a functional part, and the functional part is a component using superfluid helium as refrigeration working medium, including a heat exchanger, a dilution refrigerator unit or a superfluid pulse tube unit.

[0017] In an embodiment, a valve is arranged at the connection between the two ends of the storage part and the pipe.

[0018] The second aspect of the present application provides a low-temperature circulating refrigeration system, comprising the low-temperature circulating pump according to any one of the above.

[0019] The application discloses a low-temperature circulating pump and a low-temperature circulating refrigeration system, the low-temperature circulating pump comprising: a storage part, the storage part comprising a first storage part and a second storage part connected in series by superfluid, and the first storage part and the second storage part being a paramagnetic salt storage part and an antiferromagnetic salt storage part respectively; a pipe, the pipe connecting two ends of the storage part, so that the superfluid moves along the pipe to realize heat exchange; and a magnet, the magnet being arranged outside the first storage part and the second storage part, and providing a changing magnetic field for the first storage part and the second storage part, so that a temperature difference is formed between the first storage part and the second storage part by the magnetocaloric effect, and the circulation flow of the superfluid in the low-temperature circulating pump is realized. The superfluid is circulated by the magnetocaloric effect of the paramagnetic salt and the antiferromagnetic salt, and the superfluid always keeps liquid state in the process, so that the large-flow and continuous refrigeration circulation is realized. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0021] Figure 1 It is a structural schematic diagram of the low-temperature circulating pump of the present application.

[0022] Figure 2 It is a schematic diagram of the relationship between the magnetic field change and the temperature change in the low-temperature circulating pump of the present application. DETAILED DESCRIPTION

[0023] The present application provides a low-temperature circulating pump and a low-temperature circulating refrigeration system, in order to make the purpose, technical scheme and effect of the present application more clear and definite, the following will further describe the present application. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0024] It should be noted that the terms "center", "upper", "lower", "left", "right", "inner", "outer", "vertical", "horizontal" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used to facilitate the description of the present application and simplify the description, and do not indicate or imply that the indicated structure must have a particular orientation or must be constructed in a particular orientation, and cannot be understood as a limitation on the present application.

[0025] In addition, unless otherwise defined, "a" or "an" shall mean one or more. If an embodiment of the application contains "first", "second", and / or "third" etc. descriptions, the "first", "second", and / or "third" etc. descriptions are merely used to describe the names of the features, and cannot be understood as indicating or implying relative importance of the features or implying the number of the features. Therefore, the features with "first", "second", and / or "third" etc. descriptions can explicitly or implicitly include at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the fact that a person skilled in the art can realize the combination, and when the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist, and is also not within the protection scope of the present application.

[0026] The boiling point of helium is 4.2K, which is much lower than other gases, so the separation of helium gas was not realized until the end of the 19th century. With the successful realization of helium liquefaction, superconductivity, superfluidity and other phenomena have been discovered one after another, and the field of low-temperature physics has developed greatly. Superfluidity is a quantum effect in a macroscopic range, which is often formed under ultra-low temperature conditions. The object with superfluidity is called superfluid, which has the characteristics of extremely high thermal conductivity and zero internal friction coefficient, i.e. completely non-viscous. Therefore, the superfluid can flow endlessly without friction, and due to its extremely high thermal conductivity, the superfluid is an excellent refrigerant, which is often used in refrigeration systems for achieving ultra-low temperature environment.

[0027] When the temperature drops to 2.17K, helium atoms occupy the lowest energy state, at which time the helium atoms gather to form superfluid, which can overcome gravity to flow upward, pass through small pores and has extremely high thermal conductivity efficiency. Therefore, superfluid helium has broad application prospects in the field of cooling objects to ultra-low temperature refrigeration.

[0028] Superfluid helium (helium II, He II) has special two-fluid properties, which can be described by two-fluid model, that is, superfluid helium is composed of two independent and interpenetrating fluids, one is the condensate part in the ground state, the entropy is equal to zero, and the viscosity is zero, which is superfluid; the other is the normal fluid in the excited state (uncondensed), the entropy is not equal to zero, and the viscosity is ordinary fluid. The sum of the densities of the two fluids is equal to the total density of He II, and the ratio between them changes with temperature. In this case, superfluid helium has a fountain effect, also known as a thermal-mechanical effect, which refers to the phenomenon of superfluid helium flowing in a capillary tube due to temperature difference. This is because superfluid helium absorbs heat after being heated, so the superfluid part of the heated end of the capillary tube decreases. Since only superfluid can flow through the capillary tube, the superfluid component at the unheated end flows through the capillary tube to the heated end, causing the liquid level at the heated end of the capillary tube to rise to form a pressure difference, thereby causing the superfluid helium to be ejected, that is, the pressure at the warmer side is increased, driving the non-viscous superfluid helium to flow to the cooler side, thereby forming a pressure difference and causing continuous flow.

[0029] Therefore, the present application utilizes the characteristics of superfluid, forms a temperature difference between superfluids, and realizes the circulation of superfluid in the system through the fountain effect. The superfluid remains in a liquid state in the system, no additional gas circuit is needed, a compact refrigeration system structure can be realized, and the temperature raising and lowering process is not needed, the energy consumption is low, and the low-temperature regeneration period is not needed, so that a large flow and continuous refrigeration effect can be realized. Further, the present application adjusts the temperature of the superfluid under ultra-low temperature conditions through the magnetocaloric effect, thereby realizing precise temperature control. The magnetocaloric effect refers to the synchronous change of the temperature of a magnetic material with the change of the magnetic field when the magnetic field changes. For different materials and different magnetic field change ranges, the temperature change law caused by the magnetocaloric effect is not the same. For paramagnetic salt, the temperature is proportional to the magnetic field strength; for antiferromagnetic salt, the temperature is inversely proportional to the magnetic field strength. In this way, the present application sets adjacent paramagnetic salt regions and antiferromagnetic salt regions to form a temperature difference between superfluids, so that the superfluid circulates in the circulation pump, realizing a large flow and continuous refrigeration effect.

[0030] Specifically, the present application provides a low-temperature circulation pump, wherein, as Figure 1As shown, the low-temperature circulating pump comprises a storage part 100, a pipeline 200 and a magnet 300. The storage part 100 comprises a first storage part 110 and a second storage part 120 connected in series by a superfluid 130 to store superfluids respectively, and the first storage part 110 and the second storage part 120 are paramagnetic salt storage parts and antiferromagnetic salt storage parts respectively; the pipeline 200 connects two ends of the storage part 100 to enable the superfluids to move along the pipeline 200 to realize heat exchange; the magnet 300 is arranged outside the first storage part 110 and the second storage part 120 to provide a changing magnetic field for the first storage part 110 and the second storage part 120, and form a temperature difference between the first storage part 110 and the second storage part 120 through the magnetocaloric effect to realize the circulating flow of the superfluids in the low-temperature circulating pump. By selecting one of the first storage part 110 and the second storage part 120 to form a paramagnetic salt storage part and the other to form an antiferromagnetic salt storage part, the magnetocaloric effect between the first storage part 110 and the second storage part 120 is opposite, so that a temperature difference is formed between the first storage part 110 and the second storage part 120 when the magnet 300 applies the same changing magnetic field to the first storage part 110 and the second storage part 120, so that the superfluids stored in the first storage part 110 and the second storage part 120 circulate along the pipeline 200 under the action of the fountain effect, thereby realizing a large-flow and continuous refrigeration effect.

[0031] In an embodiment, the superfluid is 3 He and 4 He mixture 4 He or pure 4 He 4 He, different superfluid helium is selected based on different working conditions. Whether it is a mixture or pure 4 He, the superfluid helium contains two kinds of helium, has two-fluid properties, and changes the proportion of the two kinds of helium with temperature change, so that the content of the superfluid helium in the fluid in different temperature regions is different when the temperature changes, the superfluid helium spontaneously flows to form a pressure difference through the potential difference, thereby triggering the fountain effect to make the superfluid circulate in the low-temperature circulating pump, which not only avoids the low-temperature regeneration period to ensure continuous refrigeration, but also avoids the process of warming the superfluid to room temperature and recondensing, thereby reducing the overall energy consumption.

[0032] In an embodiment, the first storage part 110 and the second storage part 120 are in a cylindrical structure to ensure uniform stress, prolong the service life, and avoid leakage of the superfluid stored inside.

[0033] In an embodiment, one of the first storage 110 and the second storage 120 stores paramagnetic salt particles and the superfluid, forming the paramagnetic salt storage, and the other stores antiferromagnetic salt particles and the superfluid, forming the antiferromagnetic salt storage. Optionally, the first storage 110 is the paramagnetic salt storage, and the second storage 120 is the antiferromagnetic salt storage; or the first storage 110 is the antiferromagnetic salt storage, and the second storage 120 is the paramagnetic salt storage. As long as the magnetocaloric effects of the first storage 110 and the second storage 120 are opposite, the varying magnetic field can be effectively utilized to form a more obvious temperature gradient between the first storage 110 and the second storage 120, so that the superfluid can be circulated in the low-temperature circulating pump with a smaller change in the magnetic field, and the energy consumption is lower.

[0034] In an embodiment, the magnet 300 is a superconducting magnetic coil surrounding the first storage 110 and the second storage 120. Specifically, the magnet 300 is an integrated superconducting magnetic coil, which simultaneously surrounds the first storage 110 and the second storage 120, so that the overall structure of the low-temperature circulating pump is more compact, and the use of superconducting magnets is reduced, further reducing the cost of the low-temperature circulating pump.

[0035] In an embodiment, the magnet 300 provides a linearly varying magnetic field to the first storage 110 and the second storage 120, and the greater the magnitude of the change in the magnetic field, the better the performance of the low-temperature circulating pump. By setting the magnetocaloric effects of the first storage 110 and the second storage 120 to be opposite, the required temperature gradient can be achieved with a smaller change in the magnetic field. Optionally, the lower limit of the varying magnetic field is 0, and the upper limit of the varying magnetic field is set based on the required performance of the low-temperature circulating pump, so that the normal use of the low-temperature circulating pump is ensured, and the energy consumption is further reduced by limiting the change in the magnetic field. Optionally, the varying magnetic field is a linearly varying magnetic field that varies between 0 and 1.5T.

[0036] In an embodiment, the super-leak 130 is a material with micro-nano pores. The super-leak formed by the material with micro-nano pores is used as a capillary channel between the first storage 110 and the second storage 120, allowing only part of the superfluid to pass, so as to form a pressure difference between the first storage 110 and the second storage 120, and ensure that the superfluid circulates along the low-temperature circulating pump under the fountain effect.

[0037] In one embodiment, the conduit 200 is connected to a functional unit 210 to achieve the required cooling function when the superfluid flows through the functional unit 210. Specifically, the functional unit 210 is a component that uses superfluid helium as the refrigerant. Depending on different cooling requirements, the functional unit 210 can be a heat exchanger, a dilution refrigeration unit, or a superfluid pulse tube unit to accommodate different cooling methods. Optionally, the conduit 200 is a capillary tube and is configured with a reciprocating structure to provide a larger contact area between the overall refrigeration system and the circulating superfluid, ensuring the overall cooling effect.

[0038] In one embodiment, valves are provided at the connections between the storage unit 100 and the pipe 200 at both ends. Optionally, valves 220 are respectively provided at the connections between the pipe 200 and the storage unit 100 at both ends to control the circulation flow rate of the superfluid in the cryogenic circulating pump when the magnetic field is strengthened (magnetization process) and weakened (demagnetization process), thereby controlling the overall cooling effect.

[0039] This invention utilizes the difference in magnetocaloric effect between paramagnetic and antiferromagnetic salts in a changing magnetic field to create a temperature gradient region within the cryogenic circulating pump. This allows for the circulation of the superfluid through the fountain effect, achieving a high-flow-rate and continuous cooling effect. The principle and setting parameters of the cryogenic circulating pump described in this invention are briefly described below with reference to the accompanying drawings.

[0040] like Figure 1 As shown, the cryogenic circulating pump of the present invention first forms a closed circulation loop through a storage section 100 and a pipe 200. The storage section 100 stores superfluid, and the pipe 200 is connected to both ends of the storage section 100, forming a loop for the superfluid to circulate. Simultaneously, a functional section 210 is provided on the pipe 200 to achieve heat exchange when the superfluid flows through, thus achieving a cooling effect. Specifically, the functional section 210 is a component using superfluid helium as the refrigerant, and can be configured as a heat exchanger, a dilution refrigeration unit, or a superfluid pulse tube unit, depending on the required cooling method.

[0041] In this embodiment, valves 220 are respectively provided at the connection points between the two ends of the pipe 200 and the two ends of the storage section 100 to control the flow rate of the superfluid flowing out from the two ends of the storage section 100.

[0042] Furthermore, the storage unit 100 includes a first storage unit 110 and a second storage unit 120 connected in series via an ultrafluid 130, and stores superfluid in the first storage unit 110 and the second storage unit 120. The superfluid is... 3 He and 4 Superfluidity in He mixture 4He or pure 4 Superfluid state of He 4 He, wherein, when a superfluid pulse tube refrigerator needs to be driven, the working medium is selected as pure 4 He; when a dilution refrigerator needs to be driven, the working medium is selected as 3 He and 4 He mixture. Further, the super leak 130 is a material with micro-nano pores, and is optionally selected as porous Vycor glass. Further, the first storage part 110 and the second storage part 120 are in a cylindrical structure, and respectively store paramagnetic salt particles and anti-ferromagnetic salt particles in the first storage part 110 and the second storage part 120, to ensure that the magneto-caloric effects of the first storage part 110 and the second storage part 120 are opposite.

[0043] In this embodiment, the first storage part 110 stores anti-ferromagnetic salt particles to form an anti-ferromagnetic salt storage part, and the second storage part 120 stores paramagnetic salt particles to form a paramagnetic salt storage part. Optionally, the anti-ferromagnetic salt particles in the first storage part 110 have a void volume of 30% of the volume of the entire first storage part 110, and the paramagnetic salt particles in the second storage part 120 have a void volume of 30% of the volume of the entire second storage part 120, to ensure that the superfluid stored in the first storage part 110 and the second storage part 120 can flow smoothly. Porous heat-resistant glass (Vycor glass) with micro-nano pores is arranged between the first storage part 110 and the second storage part 120 as the super leak 130, to ensure that only superfluid can flow between the first storage part 110 and the second storage part 120 through the super leak 130, so as to ensure that the superfluid flows through the super leak 130 when a temperature gradient is formed between the first storage part 110 and the second storage part 120, a pressure difference is formed between the first storage part 110 and the second storage part 120, so as to form a fountain effect to realize the circulation flow of the superfluid in the low-temperature circulating pump.

[0044] In this embodiment, the magnet 300 is a superconducting magnetic coil, and the magnet 300 simultaneously surrounds both the first storage section 110 and the second storage section 120 to apply the same linearly varying magnetic field to both. This linearly varying magnetic field prevents abrupt changes in the temperature difference between the first storage section 110 and the second storage section 120. Furthermore, since the magnetocaloric effects between the first storage section 110 and the second storage section 120 are opposite, the magnet 300 only requires a small varying magnetic field to create the necessary temperature gradient between them. Therefore, a smaller superconducting magnetic coil can be used, reducing the amount of magnet 300 used, lowering costs, and making the cryogenic circulation pump more compact. Moreover, it can both heat up and cool down, creating a larger temperature gradient than a single heating process, resulting in superior performance.

[0045] In this embodiment, the superfluid is a mixture. 3 He and 4 He's superfluid helium, and further, the initial superfluid helium 3 The concentration of He is 3%. The relationship between the pressure and temperature of the superfluid helium within the cryogenic circulating pump is as follows:

[0046]

[0047] Where P is the pressure of the superfluid helium, T is the current temperature of the superfluid helium, and Δ1, Δ2, A, B, C, and V are all constants, where Δ1 = 8.65 K, Δ2 = 15.7 K, A = 23.2 J / mol, and B = 6.75 × 10⁻⁶. -6 J / molK 4 , C=500J / mol, V=27.58×10 -6 m 3 / mol.

[0048] By calculating the required temperature for the superfluid helium to achieve the fountain effect, the magnet 300 can be used to determine the changing magnetic field provided by the magnet 300 to the first storage section 110 and the second storage section 120. This allows for more effective circulation of the superfluid helium within the cryogenic circulating pump, providing a large flow rate and continuous cooling effect.

[0049] The working process of the cryogenic circulating pump described in this embodiment is as follows:

[0050] like Figure 2As shown, the lowermost (black) is the curve of the magnetic field strength, and the uppermost (blue) is the temperature curve of the paramagnetic salt temperature with the magnetic field strength, and the middle (red) is the temperature curve of the antiferromagnetic salt with the magnetic field strength. Therefore, in the low-temperature circulating pump, when the magnet 300 applies a gradually linearly increasing magnetic field to the first storage part 110 and the second storage part 120, as the magnetization process proceeds, the overall magnetic field strength increases, and due to the magnetocaloric effect, the temperature of the paramagnetic salt in the second storage part 120 increases and the temperature of the antiferromagnetic salt in the first storage part 110 decreases, a temperature gradient is generated between the first storage part 110 and the second storage part 120, the temperature of the superfluid helium in the second storage part 120 is greater than the temperature of the superfluid helium in the first storage part 110, so the concentration of the superfluid helium in the second storage part 120 decreases, a chemical potential difference is formed between the superfluid helium in the second storage part 120 and the superfluid helium in the first storage part 110, the superfluid helium in the first storage part 110 moves to the second storage part 120 through the super-leak 130, so that the pressure in the second storage part 120 increases, and the superfluid helium in the second storage part 120 flows out through the pipeline 200, enters the first storage part 110 after passing through the functional part 210, and realizes the circulation of the superfluid helium in the low-temperature circulating pump; and when the magnet 300 applies a gradually linearly decreasing magnetic field to the first storage part 110 and the second storage part 120, as the demagnetization process proceeds, the overall magnetic field strength decreases, and due to the magnetocaloric effect, the temperature of the paramagnetic salt in the second storage part 120 decreases and the temperature of the antiferromagnetic salt in the first storage part 110 increases, a temperature gradient is generated between the first storage part 110 and the second storage part 120, the temperature of the superfluid helium in the first storage part 110 is greater than the temperature of the superfluid helium in the second storage part 120, so the concentration of the superfluid helium in the first storage part 110 decreases, a chemical potential difference is formed between the superfluid helium in the first storage part 110 and the superfluid helium in the second storage part 120, the superfluid helium in the second storage part 120 moves to the first storage part 110 through the super-leak 130, so that the pressure in the first storage part 110 increases, and the superfluid helium in the first storage part 110 flows out through the pipeline 200, enters the second storage part 120 after passing through the functional part 210, and realizes the circulation of the superfluid helium in the low-temperature circulating pump.

[0051] Thus, the low-temperature circulating pump forms an alternating temperature increasing and decreasing process on the first storage part 110 and the second storage part 120 through the pulse type magnetic field change, thereby forming a greater temperature gradient than a single heating process, providing stronger working performance, and ensuring that the low-temperature circulating pump can realize a large flow and continuous refrigeration effect.

[0052] Further, based on the low-temperature circulating pump, the application further provides a low-temperature circulating refrigeration system, which comprises the low-temperature circulating pump and a space or object to be refrigerated in heat exchange with the low-temperature circulating pump.

[0053] In summary, the application discloses a low-temperature circulating pump and a low-temperature circulating refrigeration system. The low-temperature circulating pump comprises a storage part, a pipe and a magnet. The storage part comprises a first storage part and a second storage part connected in series by superfluid, and the first storage part and the second storage part are a paramagnetic salt storage part and an antiferromagnetic salt storage part respectively. The pipe connects two ends of the storage part to make the superfluid move along the pipe to realize heat exchange. The magnet is arranged outside the first storage part and the second storage part to provide a changing magnetic field for the first storage part and the second storage part, and a temperature difference is formed between the first storage part and the second storage part by the magnetocaloric effect to realize the circulating flow of the superfluid in the low-temperature circulating pump. The superfluid is circulated by the magnetocaloric effect of the paramagnetic salt and the antiferromagnetic salt, and the superfluid always keeps liquid state in the process, so that the large-flow and continuous refrigeration circulation is realized.

[0054] The above-mentioned embodiments are only used to illustrate the technical solutions of the application, but not limit the application; although the application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent ones; the modification or replacement does not deviate from the spirit and scope of the technical solutions of the foregoing embodiments, and should be included in the protection scope of the application.

Claims

1. A cryogenic circulating pump, characterized in that, include: The storage unit includes a first storage unit and a second storage unit connected in series via an ultra-leakage to store the superfluid, wherein the first storage unit and the second storage unit are respectively a paramagnetic salt storage unit and an antiferromagnetic salt storage unit; A pipe, which connects the two ends of the storage unit, allows the superfluid to move along the pipe to achieve heat exchange; A magnet is disposed outside the first storage section and the second storage section to provide a changing magnetic field for the first storage section and the second storage section. A temperature difference is formed between the first storage section and the second storage section through the magnetocaloric effect, thereby realizing the circulation of the superfluid in the cryogenic circulation pump. Wherein, the superfluid is and Superfluidity in the mixture or pure superfluidity in The superfluid has a zero internal friction coefficient at 2.17 K; The superfluid is a material with micro-nano pores, which serves as a capillary channel between the first storage section and the second storage section, allowing only the superfluid portion to pass through, thereby creating a pressure difference between the first storage section and the second storage section, ensuring that the superfluid circulates along the cryogenic circulating pump under the fountain effect.

2. The cryogenic circulating pump according to claim 1, characterized in that, The first storage section and the second storage section are cylindrical structures.

3. The cryogenic circulating pump according to claim 2, characterized in that, One of the first storage section and the second storage section stores paramagnetic salt particles and the superfluid, forming the paramagnetic salt storage section, and the other stores antiferromagnetic salt particles and the superfluid, forming the antiferromagnetic salt storage section.

4. The cryogenic circulating pump according to claim 1, characterized in that, The magnet is a superconducting magnetic coil surrounding the first storage unit and the second storage unit.

5. The cryogenic circulating pump according to claim 4, characterized in that, The magnet provides a linearly varying magnetic field to the first storage unit and the second storage unit.

6. The cryogenic circulating pump according to claim 1, characterized in that, The pipeline connection is equipped with a functional unit, which is a component that uses superfluid helium as the refrigerant, including a heat exchanger, a dilution refrigeration unit, or a superfluid pulse tube unit.

7. The cryogenic circulating pump according to claim 1, characterized in that, Valves are provided at the connection points between the two ends of the storage section and the pipeline.

8. A low-temperature cyclic refrigeration system, characterized in that, Including the cryogenic circulating pump as described in any one of claims 1-7.

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