Interference resistant cryogenic dewar

Abstract

This invention discloses an anti-interference cryogenic Dewar device, comprising a shell, a Dewar assembly, and a sample rod assembly. The shell is a cylindrical structure with an open top and is fitted outside the Dewar assembly. The sample rod assembly is disposed inside the Dewar assembly. The Dewar assembly includes a cap, a first insulating sleeve, and a second insulating sleeve. The sample rod assembly includes a sample rod, a connecting plate, a sample stage, a superconducting coil, and a resistive coil. The advantages of this invention are that it uses liquid nitrogen and liquid helium chambers for cooling, and the first and second vacuum chambers reduce the outward transmission of cryogenic temperature, ensuring the accuracy of cooling the sample end of the sample rod assembly. The liquid helium chamber cools the sample stage and superconducting coil, meeting the cryogenic requirements for the superconducting coil to enter the superconducting state. When external interference signals or vibrations occur, the superconducting coil generates induced currents to reduce or eliminate the interference signals and vibrations, improving the accuracy of experimental data.

Description

Technical Field

[0001] This invention relates to the field of Dewar device technology, specifically to an anti-interference low-temperature Dewar device. Background Technology

[0002] In basic scientific research and experiments, cryogenic Dewars are indispensable devices. They provide near-absolute-zero environments for cutting-edge research in superconducting materials, quantum computing, and low-temperature physics. In superconducting experiments, they are used to maintain the sample region at a low temperature of 2-4K, ensuring experimental accuracy. In materials research, they are used to test the thermophysical properties, mechanical properties, and magnetocaloric characteristics of materials at low temperatures. Furthermore, they are used for temperature control of precision instruments, such as voltage regulation of Zener diodes, reducing measurement errors by stabilizing the temperature.

[0003] Traditional low-temperature Dewars cannot reduce or eliminate external interference signals such as environmental current ripple and vibration in harsh experimental environments, such as water-cooled magnets and other experimental devices, leading to distortion of scientific experimental data.

[0004] Although Chinese invention patent document CN119361285A discloses a superconducting magnet conduction cooling cryogenic device that utilizes a separate design of liquid helium tank and cryogenic refrigerator, transferring cooling energy to helium gas through a helium liquefaction heat exchanger, and combining a radiation screen and a bellows structure to achieve stability and convenient replacement in a cryogenic environment, the space at the center hole of the water-cooled magnet is small. In the aforementioned patent, the vacuum cavity of the device is equipped with structures such as the refrigerator assembly, which occupy a large space and cannot be installed at the center hole of the water-cooled magnet. Summary of the Invention

[0005] The technical problem to be solved by this invention is how to reduce external interference signals of the water-cooled magnet device, improve the accuracy of experimental data, and reduce the size of the device.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] An anti-interference low-temperature Dewar device includes a housing, a Dewar assembly, and a sample rod assembly. The housing is a cylindrical structure with an open top and is fitted outside the Dewar assembly. The sample rod assembly is disposed inside the Dewar assembly. The Dewar assembly includes a cap, a first insulating sleeve, and a second insulating sleeve. The cap is located at the top opening of the housing. The top of the first insulating sleeve is open and is located inside the housing, forming a first vacuum chamber with a gap between it and the housing. One end of the second insulating sleeve is located inside the first insulating sleeve and has a gap between it and the first insulating sleeve, forming a second vacuum chamber that communicates with the first vacuum chamber. The other end is located outside the cap. A liquid nitrogen chamber is provided on the wall of the first insulating sleeve. The inner cavity of the second insulating sleeve is a liquid helium chamber. The sample rod assembly is located inside the second insulating sleeve. The sample rod assembly includes a sample rod, a connecting plate, a sample stage, a superconducting coil, and a stop coil. The sample rod is sealed to the top of the second insulating sleeve through the connecting plate, and the other end extends into the bottom of the second insulating sleeve and is connected to the sample stage. The sample stage has a sample cavity inside, and multiple sets of superconducting coils that wrap around the sample cavity are insulated on the sample stage. A stop coil is also coaxially sleeved on the outermost superconducting coil.

[0008] This invention cools the sample rod assembly using liquid nitrogen and liquid helium chambers. The first and second vacuum chambers reduce the leakage of low-temperature material from the second insulating sleeve, ensuring precise cooling of the sample end of the sample rod assembly. The liquid helium chamber also cools the sample stage and superconducting coil, meeting the low-temperature requirements for the superconducting coil to enter superconductivity. When external interference or vibration occurs, the superconducting coil generates induced currents to reduce or eliminate the interference, improving the accuracy of experimental data. During operation, heat is generated. When the sample temperature needs to rise according to scientific research, the resistance coil can be energized to raise the temperature at the sample stage. Furthermore, the elimination of a cooling unit within the housing reduces the overall size of the housing, allowing for installation at the center hole of the water-cooled magnet.

[0009] Preferably, the cover is provided with multiple first flanges communicating with the liquid nitrogen chamber and second flanges communicating with the inner cavity of the shell.

[0010] Preferably, the outer walls of both the first and second insulating sleeves are provided with an insulating layer.

[0011] Preferably, the second insulating sleeve includes an outer insulating sleeve, a bellows, and a liquid helium cylinder. One end of the outer insulating sleeve passes through the cap and communicates with the bellows, while the other end is located outside the cap. The end of the bellows away from the cap communicates with the liquid helium cylinder. The sample rod is sealed to the top of the outer insulating sleeve via a connecting plate, and the other end passes through the outer insulating sleeve and the bellows in sequence and extends into the bottom of the liquid helium cylinder to connect with the sample stage.

[0012] Preferably, the cap is provided with multiple third flanges that communicate with the liquid helium chamber, one of which extends into the bottom of the liquid helium cylinder, and the outer insulating sleeve is also provided with a fourth flange.

[0013] Preferably, a wiring cavity is provided inside the sample rod.

[0014] Preferably, the sample stage includes a support plate and a sample head. One end of the sample head is connected to the bottom of the sample rod, and the other end is connected to the support plate. The sample cavity is set inside the sample head. The superconducting coil and the resistive coil are both wrapped around the outside of the sample head and insulated on the support plate.

[0015] Preferably, the support plate is further provided with an insulating structure, which includes an insulating plate, an insulating sleeve and an insulating pressure plate. The insulating plate is fixed on the support plate, and the superconducting coil and the resistive coil are both located on the insulating plate. The insulating sleeve is located on the innermost inner wall of the superconducting coil, and the insulating pressure plate is pressed on the top of the superconducting coil and the resistive coil.

[0016] Preferably, the top surface of the insulating plate is provided with multiple circumferential slots for securing the superconducting coil, and the resistive coil is connected to the insulating plate through threaded pins.

[0017] Preferably, the top surface of the insulating plate and the bottom surface of the insulating pressure plate are provided with multiple radial grooves.

[0018] Compared with the prior art, the beneficial effects of the present invention are: This invention cools the sample rod assembly using liquid nitrogen and liquid helium chambers. The first and second vacuum chambers reduce the leakage of low-temperature material from the second insulating sleeve, ensuring precise cooling of the sample end of the sample rod assembly. The liquid helium chamber also cools the sample stage and superconducting coil, meeting the low-temperature requirements for the superconducting coil to enter superconductivity. When external interference or vibration occurs, the superconducting coil generates induced currents to reduce or eliminate the interference, improving the accuracy of experimental data. During operation, heat is generated. When the sample temperature needs to rise according to scientific research, the resistance coil can be energized to raise the temperature at the sample stage. Furthermore, the elimination of a cooling unit within the housing reduces the overall size of the housing, allowing for installation at the center hole of the water-cooled magnet. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the anti-interference low-temperature Dewar device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the shell structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the Dewar assembly according to an embodiment of the present invention; Figure 4 This is another structural schematic diagram of the Dewar assembly according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the sample rod assembly according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the sample stage according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the insulation structure according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the insulating pressure plate according to an embodiment of the present invention.

[0020] In the diagram: 1. Shell; 11. Countersunk hole; 12. Sealing groove; 2. Dewar assembly; 21. Cover; 22. First insulating sleeve; 2201. Liquid nitrogen chamber; 23. Second insulating sleeve; 2301. Liquid helium chamber; 231. Outer insulating sleeve; 232. Bellows; 233. Liquid helium cylinder; 201. First vacuum chamber; 202. Second vacuum chamber; 24. First flange; 25. Second flange; 26. Third flange. 27. Fourth flange tube; 3. Sample rod assembly; 31. Sample rod; 3101. Cable routing cavity; 32. Connecting plate; 33. Sample stage; 331. Support plate; 332. Sample head; 3301. Sample cavity; 3302. Liquid guide hole; 34. Superconducting coil; 35. Resistance coil; 36. Insulation structure; 361. Insulation plate; 3611. Slot; 362. Insulation sleeve; 363. Insulation pressure plate; 3601. Radial groove. Detailed Implementation

[0021] To facilitate understanding of the technical solution of the present invention by those skilled in the art, the technical solution of the present invention will now be further described in conjunction with the accompanying drawings.

[0022] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0023] In this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically limited.

[0024] See Figure 1 This embodiment discloses an anti-interference low-temperature Dewar device, including a housing 1, a Dewar assembly 2, and a sample rod assembly 3. The housing 1 is a cylindrical structure with an open top and is sleeved on the outside of the Dewar assembly 2. The sample rod assembly 3 is disposed inside the Dewar assembly 2.

[0025] See Figure 2 The housing 1 is a hollow U-shaped cylinder with a flange at the top. The flange is provided with multiple countersunk holes 11 and two sets of sealing grooves 12 for sealing connection with the Dewar assembly 2 through multiple bolts and two sets of sealing rings.

[0026] See Figure 3 The Dewar assembly 2 includes a cover 21, a first insulating sleeve 22, and a second insulating sleeve 23. The cover 21 is sealed to the flange at the top opening of the housing 1 by bolts and a sealing ring. The top of the first insulating sleeve 22 is open and is located inside the housing 1, forming a first vacuum chamber 201 with a gap between it and the inner wall of the housing 1. One end of the second insulating sleeve 23 is located inside the first insulating sleeve 22, forming a second vacuum chamber 202 with a gap between it and the first insulating sleeve 22, and the other end is located outside the cover 21. There is a gap between the top of the first insulating sleeve 22 and the bottom surface of the cover 21, which causes the first vacuum chamber 201 to communicate with the second vacuum chamber 202. The sample rod assembly 3 is located inside the second insulating sleeve 23.

[0027] The first insulating sleeve 22 has a liquid nitrogen chamber 2201 on its wall, and the second insulating sleeve 23 has a liquid helium chamber 2301 inside its cavity.

[0028] The second insulating sleeve 23 includes an outer insulating sleeve 231, a bellows 232, and a liquid helium cylinder 233. One end of the outer insulating sleeve 231 passes through the cap 21 and is connected to the bellows 232, while the other end is located outside the cap 21. The end of the bellows 232 away from the cap 21 is connected to the liquid helium cylinder 233. The bellows 232 serves to lengthen the heat conduction path and reduce the transfer of low temperature to the outside.

[0029] Furthermore, the outer walls of the first insulating sleeve 22 and the liquid helium cylinder 233 are both provided with insulating layers, which are used to reduce the heat transfer of liquid nitrogen in the liquid nitrogen cavity 2201 to the vacuum cavity and the outside world, and to reduce the heat transfer of liquid helium in the liquid helium cavity 2301 to the vacuum cavity and the outside world, respectively.

[0030] Furthermore, the cover 21 is equipped with multiple first flange pipes 24 communicating with the liquid nitrogen chamber 2201 and second flange pipes 25 communicating with the inner cavity of the shell 1. Specifically, one end of the first flange pipe 24 passes through the cover 21 and communicates with the liquid nitrogen chamber 2201, while the other end is located outside the cover 21 for connection to an external liquid nitrogen input system and liquid nitrogen output system, enabling the input of liquid nitrogen into the liquid nitrogen chamber 2201 and the removal of nitrogen gas, thereby achieving cooling of the internal structure of the first insulating sleeve 22. The second flange pipe 25 is used for evacuating the internal cavity of the shell 1 and monitoring the vacuum level. The vacuum level of the vacuum chamber generally reaches 10. - 3 Pa forms the low-temperature zone of the liquid helium cavity 2301 and the low-temperature zone of the liquid nitrogen cavity 2201, creating an insulating layer that greatly reduces the heat conduction of the liquid helium cavity 2301 due to convection. The liquid nitrogen cavity 2201 forms a liquid nitrogen low-temperature zone with a temperature of about 77K. The liquid helium cavity 2301 is used to house the sample rod assembly 3, providing a liquid helium low-temperature environment of about 2K (which can be called the liquid helium low-temperature zone) for the sample end of the sample rod assembly 3.

[0031] See Figure 4 The cover 21 is provided with multiple third flange pipes 26 that communicate with the liquid helium chamber 2301. One of the third flange pipes 26 extends into the bottom of the liquid helium cylinder 233, which not only allows the liquid helium to flow into the bottom of the liquid helium cylinder 233 quickly, reducing the outward transmission of low temperature during its flow, but also reduces the flow area of ​​the liquid helium, further reducing the outward transmission of low temperature during its flow.

[0032] Furthermore, the outer insulation sleeve 231 is also equipped with a fourth flange pipe 27 for helium gas discharge. When the temperature inside the outer insulation sleeve 231 exceeds 4K, the helium gas can be discharged through the fourth flange pipe 27 by appropriately increasing the negative pressure to the third flange pipe 26, so that the temperature of the liquid helium chamber 2301 at the bottom of the outer insulation sleeve 231 reaches 2-4K.

[0033] See Figure 5 The sample rod assembly 3 includes a sample rod 31, a connecting plate 32, a sample stage 33, a superconducting coil 34, a resistive coil 35, and an insulating structure 36. The sample rod 31 is sealed to the top of the outer insulating sleeve 231 through the connecting plate 32. The other end passes through the outer insulating sleeve 231 and the bellows 232 in sequence and extends into the bottom of the liquid helium cylinder 233 to connect to the sample stage 33. The sample stage 33 has a sample cavity 3301 inside. Multiple sets of superconducting coils 34 are insulated on the sample stage 33 to wrap the sample cavity 3301. In this embodiment, three sets of superconducting coils 34 are coaxially arranged. The superconducting coils 34 achieve a superconducting state to reduce or even eliminate ripple signals and vibrations from the external environment, thereby improving the accuracy of experimental data. A resistive coil 35 is also coaxially sleeved on the outermost superconducting coil 34. It generates heat during operation. When the device is running, if the sample temperature needs to rise according to scientific research, the resistive coil 35 can be energized to increase the temperature at the sample stage 33.

[0034] Furthermore, the sample rod 31 has a wiring cavity 3101 inside for routing coil signal lines, temperature monitoring lines, and coil input / output current lines. The connecting plate 32 has multiple connectors.

[0035] See Figure 6 The sample stage 33 includes a support plate 331 and a sample head 332. One end of the sample head 332 is threaded to the bottom of the sample rod 31 via a threaded post, and the other end is connected to the support plate 331. The sample cavity 3301 is set inside the sample head 332 for placing the sample to be tested. The superconducting coil 34 and the resistive coil 35 are both wrapped around the outside of the sample head 332 and insulated on the support plate 331 through the insulating structure 36.

[0036] Furthermore, the support plate 331 and the sample head 332 are provided with through liquid guiding holes 3302, which are connected to the sample chamber 3301 and are used to guide the liquid helium in the liquid helium cylinder 233 to the sample chamber 3301.

[0037] Furthermore, a wiring groove is provided on the sample head 332 to connect the wiring cavity 3101 and the sample cavity 3301.

[0038] See Figure 7 The insulating structure 36 includes an insulating plate 361, an insulating sleeve 362, and an insulating pressure plate 363. The insulating plate 361 is fixed on the support plate 331. The top surface of the insulating plate 361 is provided with multiple circumferential slots 3611 for engaging the superconducting coil 34. The superconducting coil 34 is positioned by the slots 3611. The resistive coil 35 is connected to the top surface of the insulating plate 361 by a threaded pin to prevent the resistive coil 35 from rotating after being energized. Since the superconducting coil 34 has no rotational force during the operation of the device, it does not need to be fixed. However, the rotational force of the resistive coil 35 must be consistent with the direction of the sample head tightening. The insulating sleeve 362 is located on the innermost inner wall of the superconducting coil 34. The insulating pressure plate 363 is pressed on the top of the superconducting coil 34 and the resistive coil 35, thereby insulating the superconducting coil 34 and the resistive coil 35 on the sample stage 33.

[0039] For further details, please refer to [link / reference]. Figure 7 and Figure 8 Multiple radial grooves 3601 are provided on the top surface of the insulating plate 361 and the bottom surface of the insulating pressure plate 363 for the inflow of liquid helium and the outflow of coil signal lines, temperature monitoring lines, and coil input and output current lines.

[0040] In this embodiment, the sample rod assembly 3 is cooled by the liquid nitrogen chamber 2201 and the liquid helium chamber 2301. The first vacuum chamber 201 and the second vacuum chamber 202 reduce the outward transmission of low temperature from the second insulating sleeve 23, ensuring the accuracy of cooling the sample end of the sample rod assembly 3. The liquid helium chamber 2301 also cools the sample stage 33 and the superconducting coil 34, meeting the low-temperature requirements for the superconducting coil 34 to enter the superconducting state. When external interference signals or vibrations occur, the superconducting coil 34 generates induced currents to reduce or eliminate the interference signals and vibrations, thus improving the accuracy of experimental data. Heat is generated during operation. When the sample temperature needs to rise according to scientific research, the resistance coil 35 can be energized to increase the temperature at the sample stage 33. Furthermore, the refrigeration unit and other structures are eliminated from the housing 1, ensuring a smaller overall volume of the housing 1, which meets the requirements for installation at the center hole of the water-cooled magnet.

[0041] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0042] The above embodiments are merely illustrative of implementation methods of the invention. The scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention.

Claims

1. An anti-interference cryogenic Dewar device, characterized in that: It includes a housing, a Dewar assembly, and a sample rod assembly. The housing is a cylindrical structure with an open top and is fitted outside the Dewar assembly. The sample rod assembly is located inside the Dewar assembly. The Dewar assembly includes a cap, a first insulating sleeve, and a second insulating sleeve. The cap is located at the top opening of the housing. The top of the first insulating sleeve is open and is located inside the housing, forming a first vacuum chamber with a gap between it and the housing. One end of the second insulating sleeve is located inside the first insulating sleeve and has a gap between it and the first insulating sleeve, forming a second vacuum chamber that communicates with the first vacuum chamber. The other end is located outside the cap. A liquid nitrogen chamber is provided on the wall of the first insulating sleeve. The inner cavity of the second insulating sleeve is a liquid helium chamber. The sample rod assembly is located inside the second insulating sleeve. The sample rod assembly includes a sample rod, a connecting plate, a sample stage, a superconducting coil, and a stop coil. The sample rod is sealed to the top of the second insulating sleeve through the connecting plate, and the other end extends into the bottom of the second insulating sleeve and is connected to the sample stage. The sample stage has a sample cavity inside, and multiple sets of superconducting coils that wrap around the sample cavity are insulated on the sample stage. A stop coil is also coaxially sleeved on the outermost superconducting coil.

2. The anti-interference cryogenic Dewar device according to claim 1, characterized in that: The cover is equipped with multiple first flanges that communicate with the liquid nitrogen chamber and second flanges that communicate with the inner cavity of the shell.

3. The anti-interference cryogenic Dewar device according to claim 1, characterized in that: Both the outer walls of the first and second insulation sleeves are provided with insulation layers.

4. An anti-interference cryogenic Dewar device according to claim 1, characterized in that: The second insulating sleeve includes an outer insulating sleeve, a bellows, and a liquid helium cylinder. One end of the outer insulating sleeve passes through the cap and is connected to the bellows, while the other end is located outside the cap. The end of the bellows away from the cap is connected to the liquid helium cylinder. The sample rod is sealed to the top of the outer insulating sleeve via a connecting plate, and the other end passes through the outer insulating sleeve and the bellows in sequence and extends into the bottom of the liquid helium cylinder to connect to the sample stage.

5. An anti-interference cryogenic Dewar device according to claim 4, characterized in that: The cap is equipped with multiple third flanges that communicate with the liquid helium chamber. One of the third flanges extends into the bottom of the liquid helium cylinder. A fourth flange is also provided on the outer insulation sleeve.

6. An anti-interference cryogenic Dewar device according to claim 1, characterized in that: The sample rod has a wiring cavity inside.

7. An anti-interference cryogenic Dewar device according to claim 1, characterized in that: The sample stage includes a support plate and a sample head. One end of the sample head is connected to the bottom of the sample rod, and the other end is connected to the support plate. The sample cavity is set inside the sample head. The superconducting coil and the resistive coil are both wrapped around the outside of the sample head and insulated on the support plate.

8. An anti-interference cryogenic Dewar device according to claim 7, characterized in that: The support plate is also equipped with an insulation structure, which includes an insulation plate, an insulation sleeve, and an insulation pressure plate. The insulation plate is fixed on the support plate, and the superconducting coil and the resistive coil are both located on the insulation plate. The insulation sleeve is located on the innermost inner wall of the superconducting coil, and the insulation pressure plate is pressed on the top of the superconducting coil and the resistive coil.

9. An anti-interference cryogenic Dewar device according to claim 8, characterized in that: The top surface of the insulating plate is provided with multiple circumferential slots for securing the superconducting coil, and the resistive coil is connected to the insulating plate through threaded pins.

10. An anti-interference cryogenic Dewar device according to claim 8, characterized in that: Multiple radial grooves are provided on the top surface of the insulating board and the bottom surface of the insulating pressure plate.

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