A continuously operating, very low temperature adiabatic demagnetization refrigeration system
By coordinating the design of the magnetic refrigeration unit, temperature control unit, and buffer chamber, and combining the thin-walled liquid-conducting neck tube and extended heat exchange structure, the problem of continuous and stable operation of the adiabatic demagnetizing refrigerator in the extremely low temperature region was solved, achieving stable cold end temperature and efficient refrigeration.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING INST OF TECH
- Filing Date
- 2026-06-01
- Publication Date
- 2026-07-10
AI Technical Summary
Traditional adiabatic demagnetizing refrigerators cannot achieve long-term continuous and stable operation in extremely low temperature regions. The cold end temperature fluctuates greatly, and the active temperature control method consumes cooling capacity and generates electrical noise, affecting high-precision experiments.
The system employs a coordinated approach of a magnetic refrigeration unit, a temperature control unit, a cold energy transfer structure, and a buffer chamber. It utilizes the gas-liquid phase change characteristics of the low-temperature working fluid to achieve continuous refrigeration. The cold energy transfer is optimized through a thin-walled liquid-conducting neck and an extended heat exchange structure, avoiding the need for additional heating devices and simplifying the control logic.
It achieves continuous and stable cooling in extremely low temperature environments, reduces thermal load and electrical noise interference, meets the long-term temperature stability requirements of high-precision applications, and extends the system's low-temperature maintenance time.
Smart Images
Figure CN122359947A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cryogenic refrigeration technology, and in particular to a continuously operating ultra-low temperature adiabatic demagnetizing refrigeration system. Background Technology
[0002] Adiabatic demagnetizing refrigerators, leveraging the magnetocaloric effect generated during the magnetization and demagnetization of magnetic materials, can achieve extremely low temperatures in the Kelvin to millikelvin range. This cooling method falls under the category of solid-state refrigeration, eliminating the need for compression and reflux of the circulating working fluid. Therefore, it boasts significant advantages such as compact structure, no moving parts, no vibration interference, and independence from gravity. It has been widely applied in cutting-edge fields such as low-temperature physics experiments, high-precision quantum measurement, and temperature control for deep space exploration equipment. However, basic adiabatic demagnetizing refrigerators are generally intermittent in operation and cannot directly achieve continuous cooling. Continuous cooling often requires a complex multi-stage structure with thermal switches to control the operating mode. This not only significantly increases the system's size and cost but also complicates the control process. More importantly, during the periodic demagnetization-magnetization cycle of the adiabatic demagnetizing refrigerator, the cold-end temperature inevitably experiences significant periodic fluctuations due to the periodic changes in the external magnetic field and the switching of the thermal switch. The magnitude of these temperature fluctuations is insufficient to meet the stringent requirements of long-term temperature stability in the milliKelvin range for some high-precision scientific experiments. To suppress these cold-end temperature fluctuations, existing technologies generally employ active temperature control schemes. Specifically, electric heaters are installed at the cold end or constant-temperature stage of the adiabatic demagnetizing refrigerator, coupled with high-precision temperature sensors and a PID feedback control loop. Adjustable thermal compensation is applied to offset the cooling capacity fluctuations caused by the cooling cycle. However, this control method, which relies on external heat sources for compensation, has significant drawbacks in extremely low-temperature environments below 1 K. The actively applied heat load inevitably consumes the valuable cooling capacity generated by the adiabatic demagnetizing refrigerator, thus significantly shortening the system's effective cooling duration. Simultaneously, the electric heater and its associated control circuitry generate electrical noise during operation, which can easily interfere with highly sensitive surrounding detection equipment, affecting the accuracy of experimental or detection data. Furthermore, tuning the control parameters of the temperature control system in the millikelvin temperature range is extremely difficult, often requiring technicians to invest considerable time and effort in debugging, yet still struggling to achieve long-term, low-disturbance stable operation while maintaining cooling efficiency. Therefore, the current field of cryogenic adiabatic demagnetizing refrigeration urgently needs a technical solution that can achieve continuous cooling, ensure stable cold-end temperature, introduce no additional heating losses, and has a simple control method to solve the problem of traditional adiabatic demagnetizing refrigerators' inability to operate continuously and stably for extended periods in extremely low-temperature regions. Summary of the Invention
[0003] This invention provides a continuously operating ultra-low temperature adiabatic demagnetizing refrigeration system, which aims to solve the problem that traditional adiabatic demagnetizing refrigeration machines cannot operate continuously and stably for a long time in ultra-low temperature regions.
[0004] To achieve the above objectives, the following technical solution is adopted.
[0005] A continuously operating cryogenic adiabatic demagnetizing refrigeration system, comprising:
[0006] A magnetic refrigeration unit, comprising a magnetocaloric module, a thermal switch, a superconducting magnet surrounding the magnetocaloric module, and a magnetic shielding structure; A temperature control unit, comprising a sealed container encapsulating a low-temperature working fluid, the sealed container comprising a gas phase region and a liquid storage region, the gas phase region and the liquid storage region being connected by a thin-walled liquid-conducting neck. A cold energy transfer structure is provided, wherein the cold energy transfer structure is connected between the cold end of the magnetic refrigeration unit and the gas phase region of the temperature control unit; A buffer chamber is connected to the gas phase zone of the temperature control unit via a gas phase pipeline.
[0007] Optionally, the volume of the buffer chamber is not less than 5 times the effective volume of the sealed container of the temperature control unit.
[0008] Optionally, the ratio of the length of the thin-walled liquid-conducting neck to the inner diameter of the thin-walled liquid-conducting neck is greater than or equal to 5.
[0009] Optionally, the connection between the thin-walled liquid-conducting neck and the gas phase region is formed into a conical structure.
[0010] Optionally, it also includes a vent pipe, which connects the gas phase pipeline to the liquid storage area, and the connection position of the vent pipe and the gas phase pipeline is close to the gas phase area.
[0011] Optionally, an extended heat exchange structure is provided in the gas phase region, and the extended heat exchange structure is thermally connected to the cold energy transfer structure.
[0012] Optionally, the extended heat exchange structure includes multiple longitudinal straight fins, which extend vertically and are radially distributed, with adjacent longitudinal straight fins forming a drainage channel toward the thin-walled liquid-conducting neck.
[0013] Optionally, the extended heat exchange structure is a conical guide fluid, the sidewall of which is provided with a guide slope that contracts towards the center, and the bottom outlet of the guide slope is connected to the thin-walled liquid neck tube.
[0014] Optionally, the guide slope of the conical guide fluid is provided with radial fins extending radially therefrom.
[0015] Optionally, the extended heat exchange structure includes a plurality of conical fluid guides arranged in a top-to-bottom stacked manner.
[0016] Compared with the prior art, the present invention has the following beneficial effects: This application utilizes the coordinated operation of a magnetic refrigeration unit, a temperature control unit, a cold energy transfer structure, and a buffer chamber. By leveraging the isothermal characteristics of the low-temperature working fluid's gas-liquid phase change within the temperature control unit, the intermittent cold energy output of the magnetic refrigeration unit can be transformed into a continuous and stable refrigeration process. This eliminates the need for an additional active heating device, avoiding the problems of heat load consuming cold energy and electrical noise interference. It also simplifies the system's control logic and meets the long-term stability requirements of high-precision applications in extremely low-temperature environments. Furthermore, it solves the problem that traditional adiabatic demagnetizing refrigerators cannot operate continuously and stably in extremely low-temperature regions for extended periods. The large-volume buffer structure effectively buffers pressure changes in the gas phase region of the temperature control unit, maintaining the stability of the working fluid's saturated vapor pressure and thus further improving the stability of the system's refrigeration temperature. The thin-walled liquid-conducting neck's aspect ratio design creates high axial thermal resistance, significantly reducing solid-phase heat conduction leakage between the gas phase region and the liquid storage region, and extending the system's low-temperature maintenance time. The tapered connection structure between the thin-walled liquid-conducting neck and the gas phase region, combined with the vent pipe connecting the gas phase pipeline and the liquid storage region, effectively eliminates flow obstruction caused by gas-liquid backflow, promoting smoother flow of condensed liquid to the liquid storage region for storage. The extended heat exchange structure set in the gas phase region can significantly increase the condensation heat exchange area of the low-temperature working fluid. The radially distributed longitudinal straight fins form a drainage channel towards the thin-walled liquid guide neck, guiding the condensate to quickly converge and flow. The conical guide with a guide slope can prevent droplet splashing. The stacked conical guide can further expand the heat exchange space. The radial fins on the guide slope can not only enhance the heat exchange effect, but also optimize the liquid guidance with the help of capillary force and physical barrier effect, making the condensation and regeneration process of the working fluid faster and more uniform, and comprehensively ensuring the continuous and efficient operation of the system. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the overall system structure according to the first embodiment of the present invention; Figure 2 This is a schematic diagram of the overall system structure according to the second embodiment of the present invention; Figure 3 yes Figure 2 A schematic cross-sectional view of the longitudinal straight fin structure is shown in the figure; Figure 4 This is a schematic diagram of the overall system structure according to the third embodiment of the present invention; Figure 5 yes Figure 4 The diagram shows a three-dimensional structure of a cone-shaped fluid guide. Figure 6 yes Figure 4The diagram shows a three-dimensional structure of the conical fluid guide inner radial fins. The components include: 1. Magnetic refrigeration unit; 2. Buffer chamber; 3. Temperature control unit; 4. Cold energy transfer structure; 11. Magnetothermal module; 12. Superconducting magnet and magnetic shielding structure; 13. Thermal switch; 14. Cold plate; 21. Connecting pipe; 22. Buffer chamber shell; 23. T-junction; 31. Temperature control container; 32. Liquid storage area; 33. Gas phase area; 34. Extended heat exchange structure; 341. Longitudinal straight fins; 342. Conical fluid guide. Detailed Implementation
[0018] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.
[0019] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.
[0020] Example 1 like Figure 1 As shown, this embodiment provides a continuously operating ultra-low temperature adiabatic demagnetizing refrigeration system, including a magnetic refrigeration unit 1, a temperature control unit 3, a cold energy transfer structure 4, and a buffer chamber 2.
[0021] The magnetic cooling unit 1 includes a magnetocaloric module 11, a superconducting magnet, a magnetic shielding structure 12, and a thermal switch 13. The magnetocaloric module 11 is filled with a magnetocaloric material, such as gadolinium gallium garnet (GGG). It is suspended below the cold plate 14 by an insulating support structure (e.g., a low thermal conductivity suspension made of G10 or Kevlar fiber) to ensure thermal insulation from the environment. The superconducting magnet 12 surrounds the magnetocaloric module 11 and provides a varying magnetic field. The thermal switch 13 is located between the magnetocaloric module 11 and the cold plate 14 to control the on / off state of the thermal connection. The magnetic shielding structure covers the outside of the superconducting magnet 12 to confine the magnetic field and reduce magnetic leakage interference to surrounding devices or sensitive detection equipment. The hot end of the magnetocaloric module 11 is thermally connected to the cold plate 14.
[0022] Temperature control unit 3 includes a sealed temperature control container 31, which contains a cryogenic working fluid, wherein the cryogenic working fluid is... 3 He 4The gas composition is selected from at least one of He, neon, hydrogen, nitrogen, argon, and oxygen. The internal space of the temperature-controlled container 31 is divided into a gas phase zone 33 and a liquid storage zone 32 from top to bottom. The gas phase zone 33 and the liquid storage zone 32 are connected by a thin-walled liquid-conducting neck. This thin-walled liquid-conducting neck is made of a low thermal conductivity material (such as stainless steel, titanium alloy, or ceramic), and the ratio of the length to the inner diameter of the thin-walled liquid-conducting neck is preferably set to be greater than or equal to 5, and its wall thickness is significantly less than the wall thickness of the main body of the temperature-controlled container 31. This design allows the thin-walled liquid-conducting neck to have high axial thermal resistance while allowing liquid to flow downward and gas to return upward, effectively reducing axial solid-phase heat conduction leakage between the gas phase zone 33 and the liquid storage zone 32.
[0023] One end of the cold energy transfer structure 4 is connected to the magnetic refrigeration unit magnetic heating module 11, and the other end is connected to the temperature control container 31. In this embodiment, the end connected to the gas phase region 33 can be a simple columnar structure, and the plane at the end of the columnar structure constitutes the basic heat exchange surface.
[0024] The buffer chamber 2 is located inside the buffer chamber shell 22. The buffer chamber 2 is connected to the gas phase zone 33 of the temperature control container 31 through the gas phase pipeline 21. A tee 23 is provided on the gas phase pipeline 21. The effective volume of the buffer chamber 2 is not less than 5 times the effective volume of the temperature control container 31. Through its large volume buffering effect, the saturated vapor pressure of the working fluid in the system can be kept stable, thereby making the phase change temperature more stable.
[0025] The working process of this embodiment is as follows: The system is first cooled to a base temperature (e.g., 4 K) by an upper precooling stage (such as a pulse tube refrigerator). Then, the thermal switch 13 of the magnetic refrigeration unit 1 is turned on, precooling it to a precooling temperature of 4 K, energizing the magnetic calorimeter module 11, and finally stabilizing it at the precooling temperature. The buffer chamber 2 is connected to the gas phase zone 33 of the temperature control unit 3, ensuring pressure balance.
[0026] Then, the thermal switch 13 is turned off to demagnetize the magnetothermal module 11, causing its temperature to drop, typically to below 1 K in the milliKelvin (mK) temperature range. This cooling energy is transferred to the vapor phase region 33 of the temperature-controlled container 31 through the cooling energy transfer structure 4, lowering its temperature below that of the working fluid at the current system pressure. 3 The saturation temperature of He. When the gaseous working fluid comes into contact with these low-temperature surfaces, it condenses, and the released latent heat is carried away by the cold transfer structure 4. The condensed droplets flow into the liquid storage area 32 below through the thin-walled liquid neck tube under the action of gravity. The liquid in the liquid storage area 32 gradually increases, and the total pressure of the system gradually decreases due to the gas-phase condensation.
[0027] Before the demagnetization process of the magnetocaloric module 11 ends, the condensate accumulated in the storage zone 32 reaches a preset value. At this time, the magnetocaloric module 11 is re-excited. When its temperature reaches the pre-cooling temperature, the thermal switch 13 is turned on, causing the magnetocaloric module 11 to release heat to the pre-cooling stage. During this process, the temperature of the gas phase zone 33 of the temperature control container 31 rises above that of the storage zone 32. The liquid stored in the storage zone 32 carries away the heat of the load through evaporation, continuing to provide cooling capacity for the refrigeration process and achieving continuous refrigeration. Due to the excellent insulation effect of the liquid guide neck, the axial heat leakage from the gas phase zone 33 to the storage zone 32 is very small, which can reduce the evaporation loss of the liquid working medium in the storage zone 32, thereby extending the continuous refrigeration time of the system. The generated vapor returns to the gas phase zone 33 and the buffer chamber 2 through the thin-walled liquid guide neck. Since the buffer chamber 2 has a very large volume, it maintains the stability of the system pressure, making the phase change temperature of the storage zone 32 more stable.
[0028] Before the liquid in the liquid reservoir 32 is exhausted, the magnetothermal module 11 completes the excitation process, re-demagnetizes and cools down, causing the gas in the temperature control unit 3 to condense again, and the magnetothermal module provides cooling capacity for the refrigeration process, achieving continuous refrigeration. By repeating the above steps, the intermittent, pulsed cooling capacity output by the periodic magnetization-demagnetization cycle of the magnetic refrigeration unit 1 is transformed into a continuous, temperature-stable refrigeration process provided by the temperature control unit 3 (through evaporative cooling in the liquid reservoir 32).
[0029] Example 2 like Figure 2 and Figure 3 As shown, this embodiment optimizes the heat exchange structure and liquid collection process in the gas phase region 33 based on embodiment 1.
[0030] The main difference between this embodiment and Embodiment 1 is that an extended heat exchange structure 34 is provided in the gas phase zone 33, and this extended heat exchange structure 34 is a longitudinal straight fin structure. The bottom of the temperature control container 31 adopts a conical contraction design to form a funnel-shaped conical guide section to achieve efficient collection and guidance of condensate. A vent pipe is provided between the gas phase pipeline and the liquid storage zone 32 so that the condensate in the gas phase zone 33 can flow more smoothly to the liquid storage zone 32.
[0031] Specifically, the extended heat exchange structure 34 includes a plurality of longitudinal straight fins 341 extending in a vertical direction. These longitudinal straight fins 341 are made of a high thermal conductivity metal (such as oxygen-free copper) and are radially and uniformly distributed around the end of the cold transfer structure 4 (see [link to relevant documentation]). Figure 3The fin roots and the ends of the cold transfer structure 4 are connected by welding or integral machining to achieve high thermal conductivity, ensuring efficient cold transfer to the fin surface. A vertical channel is formed between adjacent longitudinal straight fins 341, increasing the contact area of the gaseous working fluid and providing a low-resistance path for the condensate. The lower outlet of this channel faces the thin-walled liquid-guiding neck. The conical guide section at the bottom of the temperature control container 31 has a smooth inclined inner wall. Its upper large opening receives droplets from the upper fin area, and its lower small opening smoothly connects to the inlet of the thin-walled liquid-guiding neck. A vent pipe is installed between the gas phase pipeline and the liquid storage area 32, with the vent pipe connecting to the gas phase pipeline closer to the gas phase area 33. The vent pipe is a thin-walled tube made of a material with very low thermal conductivity, such as stainless steel or titanium alloy, which has a large thermal resistance. Its inner diameter is no larger than the inner diameter of the liquid-conducting neck (for example, the inner diameter of the vent pipe is less than or equal to 2 mm), minimizing heat conduction and leakage from the gas phase zone 33 to the liquid storage zone 32. The vent pipe allows for smoother gas flow between the gas phase zone 33 and the liquid storage zone 32. Some or all of the gas in the liquid storage zone 32 flows through the vent pipe to the gas phase zone 33 and the buffer chamber 2, while the liquid in the gas phase zone 33 flows smoothly into the liquid storage zone 32 through the liquid-conducting neck, avoiding flow obstruction caused by the interaction of liquid and gas within the narrow channel of the liquid-conducting neck.
[0032] During operation, the gaseous working fluid condenses on the low-temperature surface of the longitudinal straight fins 341. Under the influence of gravity or surface tension, the droplets flow down the fin surface and quickly converge into the vertical channels between the fins. The liquid flows into the conical guide section and, constrained by the inclined plane, converges towards the central axis. This not only prevents working fluid stagnation but also utilizes gravitational potential energy to increase the static pressure head of the liquid, assisting it in overcoming the gas-liquid counterflow resistance and rapidly returning to the storage area 32 through the thin-walled liquid-guiding neck. The channels between the fins provide a path for the descending liquid, while the outer area of the fins or the central area of the channels reserve space for the rising vapor. The remaining structure and operating process of this embodiment are basically the same as in Embodiment 1.
[0033] Example 3 like Figure 4 , Figure 5 and Figure 6 As shown, this embodiment provides another implementation of the extended heat exchange structure 34.
[0034] The main difference between this embodiment and embodiment 1 is that the extended heat exchange structure 34 set in the gas phase region 33 is a stacked conical fluid guiding structure.
[0035] Specifically, the extended heat exchange structure 34 is composed of multiple conical fluid guides 342 arranged in a top-to-bottom stacked manner (see...). Figure 5Each conical guide 342 is shaped like an inverted frustum or funnel and is made of a highly thermally conductive metal material (such as oxygen-free copper). Its sidewalls are inclined surfaces that taper towards the center, with an inclination angle preferably between 30° and 60°, which not only creates a large heat exchange area but also ensures that the liquid can slide down quickly. The conical guides 342 are arranged coaxially along the axis, which can effectively guide the droplets and prevent them from splashing onto the inner wall of the temperature control container 31 due to airflow disturbance, thus avoiding pressure fluctuations caused by liquid evaporation from contact with the hotter wall surface. The bottom outlet of the lowest conical guide 342 is connected to a thin-walled liquid neck tube.
[0036] Specifically, a number of radial fins 341 are integrally provided on the inner surface (i.e., the guide slope) of the conical guide 342 (see Figure 6 The fins are radially distributed and extend perpendicular to the guide slope. This further increases the heat exchange area and acts as a "guide grid," using capillary force and physical obstruction to direct condensate droplets radially into the central drain port, preventing the droplets from rotating or splashing with the airflow.
[0037] During operation, the gaseous working fluid condenses on the inclined surface of the multilayer conical guide 342. Under the influence of gravity or surface tension, the condensate droplets converge towards the center along the inclined guide surface and return to the storage area 32 through the thin-walled liquid neck. This stacked conical structure provides a large condensation heat exchange area within a limited space, and its continuous inclined guide surface greatly promotes efficient liquid collection and discharge.
[0038] Specifically, when the system adopts 4 When He is used as a cryogenic working fluid, below 2.17 K... 4 He will enter a superfluid state, resulting in a superfluid film creeping phenomenon along the container wall (i.e., the Rollin film phenomenon). To mitigate the adverse effects of this phenomenon, a small perforated structure with a sharp edge (not shown in the figure) can be provided near the connection between the liquid storage zone 32 and the liquid guide neck. When the temperature of the gas phase zone 33 is higher than that of the liquid storage zone 32, it suppresses the superfluid film creeping loss of the liquid in the liquid storage zone 32, allowing the refrigeration process to be maintained for a longer period of time. The remaining structure and working process of this embodiment are basically the same as those of Embodiment 1.
[0039] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or its equivalents are included in this invention.
Claims
1. A continuously operating cryogenic adiabatic demagnetizing refrigeration system, characterized in that, include: The magnetic refrigeration unit (1) includes a magnetic thermal module (11), a thermal switch (13), a superconducting magnet surrounding the magnetic thermal module (11), and a magnetic shielding structure (12). Temperature control unit (3), the temperature control unit (3) includes a sealed container containing a low-temperature working fluid, the sealed container includes a gas phase zone (33) and a liquid storage zone (32), the gas phase zone (33) and the liquid storage zone (32) are connected by a thin-walled liquid guiding neck tube; A cold energy transfer structure (4) is connected between the cold end of the magnetic refrigeration unit (1) and the gas phase region (33) of the temperature control unit (3); The buffer chamber (2) is connected to the gas phase zone (33) of the temperature control unit (3) through a gas phase pipeline.
2. The continuously operating cryogenic adiabatic demagnetizing refrigeration system according to claim 1, characterized in that, The volume of the buffer chamber (2) is not less than 5 times the effective volume of the sealed container of the temperature control unit (3).
3. The continuously operating cryogenic adiabatic demagnetizing refrigeration system according to claim 1, characterized in that, The ratio of the length of the thin-walled liquid-conducting neck to its inner diameter is greater than or equal to 5.
4. The continuously operating cryogenic adiabatic demagnetizing refrigeration system according to claim 3, characterized in that, The connection between the thin-walled liquid-conducting neck and the gas phase region (33) forms a conical structure.
5. A continuously operating cryogenic adiabatic demagnetizing refrigeration system according to claim 4, characterized in that, It also includes a vent pipe, which connects the gas phase pipeline to the liquid storage area (32), and the connection position of the vent pipe and the gas phase pipeline is close to the gas phase area (33).
6. A continuously operating cryogenic adiabatic demagnetizing refrigeration system according to any one of claims 1 to 5, characterized in that, An extended heat exchange structure (34) is provided in the gas phase region (33), and the extended heat exchange structure (34) is thermally connected to the cold energy transfer structure (4).
7. A continuously operating cryogenic adiabatic demagnetizing refrigeration system according to claim 6, characterized in that, The extended heat exchange structure (34) includes a plurality of longitudinal straight fins (341), which extend vertically and are radially distributed, and a drainage channel is formed between adjacent longitudinal straight fins (341) toward the thin-walled liquid guiding neck.
8. A continuously operating cryogenic adiabatic demagnetizing refrigeration system according to claim 6, characterized in that, The extended heat exchange structure (34) is a conical guide fluid (342). The sidewall of the conical guide fluid (342) is provided with a guide slope that contracts towards the center. The bottom outlet of the guide slope is connected to the thin-walled liquid neck tube.
9. A continuously operating cryogenic adiabatic demagnetizing refrigeration system according to claim 8, characterized in that, The conical guide (342) has radial fins extending radially on its guide slope.
10. A continuously operating cryogenic adiabatic demagnetizing refrigeration system according to claim 8, characterized in that, The extended heat exchange structure (34) includes multiple conical fluid guides (342) arranged in a top-to-bottom stacked manner.