Dilution refrigerator with fast warm-up function and fast warm-up method

Abstract

This invention provides a dilution refrigeration machine and method with rapid rewarming function, specifically relating to the field of dilution refrigeration technology. The refrigeration machine includes a controller, a vacuum chamber, a 50K cold shield, a 4K cold shield, a 1K radiation shield, a pre-cooling unit, a first low-temperature cold trap, a second low-temperature cold trap, a gas storage container, and a dilution unit. The vacuum chamber, 50K cold shield, 4K cold shield, and 1K radiation shield are sequentially nested from the outside in, forming a vacuum cavity. A pressure sensor is installed in the vacuum cavity. Temperature probes are installed on the 300K cold plate, 50K cold plate, 4K cold plate, and mixing chamber cold plate. Heating wires with independent heating switches are installed on the surfaces of the 50K cold shield, 4K cold shield, and 1K radiation shield. The 300K cold plate is equipped with a nitrogen inlet, a nitrogen outlet, a dense phase supply pipe, and a suction pipe. This invention can automatically adjust the pressure of the vacuum cavity. Combined with the heating elements of each cold shield, the rewarming time can be shortened to less than 4 hours, significantly reducing the equipment downtime.

Description

Technical Field

[0001] This invention patent relates to the field of dilution refrigeration technology, specifically to a dilution refrigeration machine and a rapid rewarming method with rapid rewarming function. Background Technology

[0002] In the field of dilution refrigeration, when it is necessary to perform sample replacement, internal equipment inspection, maintenance, or other operations, the entire dilution refrigeration machine must first undergo a rewarming process. The lid can only be opened and operated after the cavity has been heated to room temperature and the vacuum has been broken.

[0003] Currently, dilution refrigeration machines generally employ a method where, after the equipment is shut down, dry nitrogen is introduced into the vacuum chamber, and the temperature of each stage of the cold plate is raised by nitrogen convection heat transfer. However, the heat exchange efficiency is low by relying solely on a single gas heat exchange mode, and the entire machine can take up to 24 hours or even longer to fully recover from an extremely low temperature to room temperature. This results in an excessively long downtime waiting period and significantly reduces the equipment's turnover rate. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, the present invention provides a dilution refrigerator with rapid rewarming function and a rapid rewarming method, the specific technical solution of which is as follows: A dilution refrigerator with rapid rewarming function includes a controller, a vacuum chamber, a 50K cold shield, a 4K cold shield, a 1K radiation shield, a pre-cooling unit, a first low-temperature cold trap, a second low-temperature cold trap, a gas storage container, and a dilution unit. The vacuum chamber, 50K cold shield, 4K cold shield, and 1K radiation shield are sequentially nested together from the outside to the inside to form a vacuum cavity. A pressure sensor is installed inside the vacuum cavity. Inside the vacuum chamber, from top to bottom, are arranged a 300K cold plate, a 50K cold plate, a 4K cold plate, a distillation chamber cold plate, an intermediate cold plate, and a mixing chamber cold plate, with adjacent cold plates connected by support rods. The 300K cold plate, 50K cold plate, 4K cold plate, and mixing chamber cold plate are all equipped with temperature probes; the surfaces of the 50K cold screen, 4K cold screen, and 1K radiation shield are all equipped with heating wires with independent heating switches; the 300K cold plate is equipped with a nitrogen inlet, a nitrogen outlet, a dense phase supply pipe, and a suction pipe; the nitrogen inlet is connected to the outlet of the first cryogenic cold trap via a first suction pump, and the inlet of the first cryogenic cold trap is connected to the outlet of the gas storage container; the nitrogen outlet is connected to the inlet of the second cryogenic cold trap via a second suction pump, and the outlet of the second cryogenic cold trap is connected to the inlet of the gas storage container.

[0005] Preferably, the pre-cooling unit is provided with a primary cold head and a secondary cold head arranged vertically; the pre-cooling unit is also equipped with a vibration damping component; the vibration damping component is mounted on the upper surface of the 300K cold plate, and the pre-cooling unit is flexibly connected to the 300K cold plate through the vibration damping component.

[0006] Preferably, the dilution unit includes, from top to bottom, a distillation chamber, a shell-and-tube heat exchanger, and a mixing chamber.

[0007] Preferably, the distillation chamber is mounted on the upper surface of the cold plate of the distillation chamber via a flange; the mixing chamber is mounted on the upper surface of the cold plate of the mixing chamber via a flange.

[0008] Preferably, a corrugated pipe is provided between the 50K cold plate and the 4K cold plate; the steam outlet of the distillation chamber is connected to the inlet of the extraction pipe through the corrugated pipe, the outlet of the extraction pipe is connected to the inlet of the gas circulation pipe, and the outlet of the gas circulation pipe is connected to the inlet of the room temperature pump unit; the concentrated phase inlet of the distillation chamber is connected to the outlet of the concentrated phase supply pipe; and the inlet of the concentrated phase supply pipe is connected to the high-pressure outlet of the room temperature pump unit.

[0009] Preferably, the operating temperature of the first and second cryogenic cold traps is -100°C.

[0010] More preferably, the pressure sensor, each temperature probe, the heating switch of each heating wire, the first air pump and the second air pump are all electrically connected to the controller.

[0011] A rapid rewarming method, implemented using the aforementioned dilution refrigeration unit with rapid rewarming function, specifically includes the following steps: S1. After the dilution refrigerator stops, start the first vacuum pump and fill the vacuum chamber with nitrogen purified by the first low temperature cold trap from the nitrogen inlet of the 300K cold plate until the pressure in the vacuum chamber reaches 100mbar. Then, turn off the first vacuum pump and stop filling. S2. Turn on the heating switches of each heating wire on the 50K cold screen, 4K cold screen and 1K anti-radiation screen; S3. As the temperature inside the vacuum chamber increases, the pressure inside the chamber increases. When the pressure sensor detects that the pressure inside the vacuum chamber is greater than atmospheric pressure, the second pump starts and extracts nitrogen from the nitrogen outlet on the 300K cold plate until the pressure inside the vacuum chamber drops to 100mbar. Then the second pump stops and the extraction stops. The extracted nitrogen is purified using the second cryogenic cold trap and stored in the gas storage container. S4. When the pressure sensor detects that the pressure inside the vacuum chamber is less than 100mbar, the first pumping pump starts again and the nitrogen in the storage container is purified through the first low-temperature cold trap and then replenished into the vacuum chamber through the nitrogen inlet of the 300K cold plate. S5. Repeat S3-S4 to continuously adjust the internal pressure of the vacuum chamber; Specifically, when the temperature probe reading on the 50K cold plate is greater than that on the 300K cold plate, the heating switch of the heating wire on the 50K cold screen surface is turned off; when the temperature probe reading on the 4K cold plate is greater than that on the 300K cold plate, the heating switch of the heating wire on the 4K cold screen surface is turned off; and when the temperature probe reading on the mixing chamber cold plate is greater than that on the 300K cold plate, the heating switch of the heating wire on the 1K radiation shield surface is turned off.

[0012] The beneficial effects of this invention are: This invention enables automatic adjustment of the vacuum chamber pressure. Combined with heating elements on each cold shield surface, the rewarming time can be significantly reduced to less than 4 hours, greatly shortening the equipment downtime. It effectively solves the problems of low heat exchange efficiency and excessively long rewarming time from extremely low temperatures to room temperature in traditional rewarming methods, resulting in long downtime and low equipment utilization. Attached Figure Description

[0013] The accompanying drawings constituting this invention are provided to further understand this application and do not constitute an undue limitation of this application.

[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a top view of the present invention; Figure 3 for Figure 2 Sectional view from AA; Figure 4 This is a schematic diagram of the retemperature process of the present invention; In the diagram, 1-300K cold plate; 101-evacuation pipe; 102-nitrogen inlet; 103-nitrogen outlet; 2-50K cold plate; 3-4K cold plate; 4-distillation chamber cold plate; 5-intermediate cold plate; 6-mixing chamber cold plate; 7-vacuum hood; 8-50K cold shield; 9-4K cold shield; 10-1K radiation shield; 11-pre-stage refrigerator; 1101-vibration damping assembly; 1102-first-stage cold head; 1103-second-stage cold head; 12-corrugated pipe; 13-distillation chamber; 14-shell heat exchanger; 15-mixing chamber. Detailed Implementation

[0015] The specific implementation of the dilution refrigeration machine and rapid rewarming method with rapid rewarming function provided by the present invention will be further described with reference to the accompanying drawings and embodiments.

[0016] like Figures 1-3As shown, a dilution refrigerator with rapid rewarming function includes a controller (not shown in the figure), a vacuum chamber 7, a 50K cold shield 8, a 4K cold shield 9, a 1K radiation shield 10, a pre-cooling unit 11, a first low-temperature cold trap (not shown in the figure), a second low-temperature cold trap (not shown in the figure), a gas storage container (not shown in the figure), and a dilution unit. The vacuum chamber 7 contains, from top to bottom, a 300K cold plate 1, a 50K cold plate 2, a 4K cold plate 3, a distillation chamber cold plate 4, an intermediate cold plate 5, and a mixing chamber cold plate 6, with adjacent cold plates connected and fixed by support rods.

[0017] It is worth noting that the first and second cryogenic cold traps are cryogenic cold traps with an operating temperature of around -100°C.

[0018] Preferably, the vacuum cover 7, the 50K cold screen 8, the 4K cold screen 9, and the 1K radiation shield 10 are sequentially nested together from the outside to the inside to form a vacuum cavity.

[0019] In order to monitor the pressure inside the vacuum chamber and automatically adjust the pressure inside the chamber during the rewarming process, a pressure sensor (not shown in the figure) is installed inside the vacuum chamber.

[0020] In order to enable temperature monitoring of the internal chambers of each cold plate, temperature probes (not shown in the figure) are installed on the 300K cold plate 1, 50K cold plate 2, 4K cold plate 3 and mixing chamber cold plate 6.

[0021] It is worth noting that the surfaces of the 50K cold screen 8, 4K cold screen 9, and 1K anti-radiation screen 10 are all equipped with heating wires (not shown in the figure) with independent heating switches. The heating wires can be conventional, known existing products, and their placement can be on the outer surface of each cold screen, on the inner sidewall of each cold screen, or embedded in the sidewall of each cold screen. The specific installation location and detailed structure should not be considered as further limitations of the present invention.

[0022] Preferably, the 300K cold plate 1 is equipped with an extraction pipe 101, a nitrogen inlet 102, a nitrogen outlet 103, and a dense phase supply pipe. The nitrogen inlet 102 is connected to the outlet of the first cryogenic cold trap via a first extraction pump (not shown in the figure), and the inlet of the first cryogenic cold trap is connected to the outlet of the gas storage container. The nitrogen outlet 103 is connected to the inlet of the second cryogenic cold trap via a second extraction pump (not shown in the figure), and the outlet of the second cryogenic cold trap is connected to the inlet of the gas storage container.

[0023] Preferably, the pre-cooling unit 11 is provided with a first-stage cold head 1102 and a second-stage cold head 1103 arranged vertically; the pre-cooling unit 11 is also provided with a vibration damping component 1101 mounted on the upper surface of the 300K cold plate 1, thereby using the vibration damping component 1101 to achieve a flexible connection between the pre-cooling unit 11 and the 300K cold plate 1, isolating the mechanical vibration generated by the operation of the pre-cooling unit 11, avoiding vibration transmission, and reducing the disturbance of vibration to the heat exchange of the cold head, ensuring stable thermal contact between the first-stage cold head 1102 and the second-stage cold head 1103 and the cold plates of each stage, and reducing the additional heat leakage caused by the increase of vibration gap.

[0024] Preferably, the dilution unit includes, from top to bottom, a distillation chamber 13, a shell-and-tube heat exchanger 14, and a mixing chamber 15. The distillation chamber 13 is mounted on the upper surface of the distillation chamber cold plate 4 via a flange; the shell-and-tube heat exchanger 14 is mounted on the upper surface of the intermediate cold plate 5; and the mixing chamber 15 is mounted on the upper surface of the mixing chamber cold plate 6 via a flange.

[0025] Preferably, a corrugated pipe 12 is provided between the 50K cold plate 2 and the 4K cold plate 3. The steam outlet of the distillation chamber 13 is connected to the inlet of the suction pipe 101 on the 300K cold plate 1 through the corrugated pipe 12. The outlet of the suction pipe 101 is connected to the inlet of the gas circulation pipeline (not shown in the figure). The outlet of the gas circulation pipeline is connected to the inlet of the room temperature pump group (not shown in the figure). The concentrated phase inlet of the distillation chamber 13 is connected to the outlet of the concentrated phase supply pipe. The inlet of the concentrated phase supply pipe is connected to the high-pressure outlet of the room temperature pump group (not shown in the figure).

[0026] It is worth emphasizing that, in order to achieve automatic adjustment of pressure and temperature within the vacuum chamber, the pressure sensor, each temperature probe, the heating switch of each heating wire, the first vacuum pump, and the second vacuum pump are all electrically connected to the controller.

[0027] The following is combined Figure 4 The rapid rewarming method achieved using the aforementioned dilution refrigeration unit with rapid rewarming function is described in detail, specifically including the following steps: S1. After the dilution refrigerator stops, start the first vacuum pump and fill the vacuum chamber with nitrogen purified by the first low temperature cold trap from the nitrogen inlet 102 of the 300K cold plate 1 until the pressure in the vacuum chamber reaches 100mbar. Then, turn off the first vacuum pump and stop filling. S2. Turn on the heating switches of each heating wire on the 50K cold screen 8, 4K cold screen 9 and 1K anti-radiation screen 10; S3. As the temperature inside the vacuum chamber gradually increases, the pressure inside the chamber gradually increases: when the pressure sensor detects that the pressure inside the vacuum chamber is greater than atmospheric pressure, the second pump starts and extracts nitrogen from the nitrogen outlet 103 on the 300K cold plate 1 until the pressure inside the vacuum chamber drops to 100mbar, at which point the second pump stops and the extraction stops; the extracted nitrogen is purified using the second cryogenic cold trap and stored in a gas storage container for later use. S4. When the pressure sensor detects that the pressure in the vacuum chamber is less than 100mbar, the first pump starts again and the nitrogen in the storage container is purified by the first low temperature cold trap and then replenished into the vacuum chamber through the nitrogen inlet 102 of the 300K cold plate 1. S5. Repeat S3-S4 to continuously and automatically adjust the internal pressure of the vacuum chamber during the rewarming process; It is worth noting that during the rewarming process of this dilution refrigeration unit, when the monitoring result of the temperature probe on the 50K cold plate 2 is greater than that of the temperature probe on the 300K cold plate 1, the heating switch of the surface heating wire of the 50K cold screen 8 is turned off; when the monitoring result of the temperature probe on the 4K cold plate 3 is greater than that of the temperature probe on the 300K cold plate 1, the heating switch of the surface heating wire of the 4K cold screen 9 is turned off; when the monitoring result of the temperature probe on the mixing chamber cold plate 6 is greater than that of the temperature probe on the 300K cold plate 1, the heating switch of the surface heating wire of the 1K radiation shield 10 is turned off, until the temperature of the inner cavity of each cold screen reaches room temperature, thus completing the rewarming process.

[0028] This invention enables automatic adjustment of the vacuum chamber pressure. Combined with heating elements on each cold shield surface, the rewarming time can be significantly reduced to less than 4 hours, greatly shortening the equipment downtime. It effectively solves the problems of low heat exchange efficiency and excessively long rewarming time from extremely low temperatures to room temperature in traditional rewarming methods, resulting in long downtime and low equipment utilization.

[0029] In this invention, terms such as "upper," "lower," "bottom," and "top" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are merely used to facilitate the description of the structural relationships of the various components or elements of this invention and do not specifically refer to any particular component or element in this invention, nor should they be construed as limiting the invention. Terms such as "connected" and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of the above terms in this invention based on the specific circumstances, and they should not be construed as limiting the invention.

[0030] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A dilution refrigeration unit with rapid retemperature function, characterized in that, It includes a controller, vacuum chamber, 50K cold shield, 4K cold shield, 1K radiation shield, pre-cooling unit, first low-temperature cold trap, second low-temperature cold trap, gas storage container, and dilution unit; The vacuum enclosure, 50K cold screen, 4K cold screen and 1K radiation shield are nested together from the outside to the inside to form a vacuum cavity; a pressure sensor is installed inside the vacuum cavity. The vacuum chamber is arranged from top to bottom with a 300K cold plate, a 50K cold plate, a 4K cold plate, a distillation chamber cold plate, an intermediate cold plate, and a mixing chamber cold plate, and adjacent cold plates are connected by support rods; wherein, the 300K cold plate, the 50K cold plate, the 4K cold plate, and the mixing chamber cold plate are all equipped with temperature probes; The surfaces of the 50K cold screen, 4K cold screen and 1K anti-radiation screen are all equipped with heating wires with independent heating switches; The 300K cold plate is equipped with a nitrogen inlet, a nitrogen outlet, a dense phase supply pipe, and an extraction pipe; the nitrogen inlet is connected to the outlet of the first cryogenic cold trap via a first extraction pump, and the inlet of the first cryogenic cold trap is connected to the outlet of the gas storage container; the nitrogen outlet is connected to the inlet of the second cryogenic cold trap via a second extraction pump, and the outlet of the second cryogenic cold trap is connected to the inlet of the gas storage container.

2. The dilution refrigeration unit with rapid retemperature function according to claim 1, characterized in that, The pre-cooling unit is equipped with a primary cold head and a secondary cold head arranged vertically. The pre-cooling unit is also equipped with a shock-absorbing component; the shock-absorbing component is mounted on the upper surface of the 300K cold plate, and the pre-cooling unit is flexibly connected to the 300K cold plate through the shock-absorbing component.

3. The dilution refrigeration unit with rapid retemperature function according to claim 1, characterized in that, The dilution unit, from top to bottom, includes a distillation chamber, a shell-and-tube heat exchanger, and a mixing chamber.

4. The dilution refrigeration unit with rapid retemperature function according to claim 3, characterized in that, The distillation chamber is mounted on the upper surface of the cold plate of the distillation chamber via a flange; the mixing chamber is mounted on the upper surface of the cold plate of the mixing chamber via a flange.

5. The dilution refrigeration unit with rapid retemperature function according to claim 3, characterized in that, A corrugated pipe is installed between the 50K cold plate and the 4K cold plate; The steam outlet of the distillation chamber is connected to the inlet of the extraction pipe via a corrugated pipe, the outlet of the extraction pipe is connected to the inlet of the gas circulation pipe, and the outlet of the gas circulation pipe is connected to the inlet of the room temperature pump unit. The concentrated phase inlet of the distillation chamber is connected to the outlet of the concentrated phase supply pipe; the inlet of the concentrated phase supply pipe is connected to the high-pressure outlet of the room temperature pump unit.

6. The dilution refrigeration unit with rapid retemperature function according to claim 1, characterized in that, The operating temperature of the first and second cryogenic cold traps is -100℃.

7. The dilution refrigeration unit with rapid retemperature function according to claim 1, characterized in that, The pressure sensor, each temperature probe, the heating switch of each heating wire, the first air pump, and the second air pump are all electrically connected to the controller.

8. A rapid rewarming method, characterized in that, This is achieved using the dilution refrigeration unit with rapid rewarming function as described in any one of claims 1-7, specifically including the following steps: S1. After the dilution refrigerator stops, start the first vacuum pump and fill the vacuum chamber with nitrogen purified by the first low temperature cold trap from the nitrogen inlet of the 300K cold plate until the pressure in the vacuum chamber reaches 100mbar. Then, turn off the first vacuum pump and stop filling. S2. Turn on the heating switches of each heating wire on the 50K cold screen, 4K cold screen and 1K anti-radiation screen; S3. As the temperature inside the vacuum chamber increases, the pressure inside the chamber increases. When the pressure sensor detects that the pressure inside the vacuum chamber is greater than atmospheric pressure, the second pump starts and extracts nitrogen from the nitrogen outlet on the 300K cold plate until the pressure inside the vacuum chamber drops to 100mbar. Then the second pump stops and the extraction stops. The extracted nitrogen is purified using the second cryogenic cold trap and stored in the gas storage container. S4. When the pressure sensor detects that the pressure inside the vacuum chamber is less than 100mbar, the first pumping pump starts again and the nitrogen in the storage container is purified through the first low-temperature cold trap and then replenished into the vacuum chamber through the nitrogen inlet of the 300K cold plate. S5. Repeat S3-S4 to continuously adjust the internal pressure of the vacuum chamber; Specifically, when the temperature probe reading on the 50K cold plate is greater than that on the 300K cold plate, the heating switch of the heating wire on the 50K cold screen surface is turned off; when the temperature probe reading on the 4K cold plate is greater than that on the 300K cold plate, the heating switch of the heating wire on the 4K cold screen surface is turned off; and when the temperature probe reading on the mixing chamber cold plate is greater than that on the 300K cold plate, the heating switch of the heating wire on the 1K radiation shield surface is turned off.

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