Large-cooling-capacity ultra-low-vibration dilution refrigerating machine

Abstract

The invention provides a large-cooling-capacity ultralow-vibration dilution refrigerating machine which comprises a dilution refrigerating unit and a coke-soup refrigerating cycle unit. The dilution refrigeration unit comprises a dilution refrigeration loop, and a first-stage precooling heat exchanger and a second-stage precooling heat exchanger are arranged in the dilution refrigeration loop; the coke-soup refrigeration cycle unit comprises a coke-soup refrigeration cycle loop, a single-stage refrigerator with a single cold head and a two-stage refrigerator with a first-stage cold head and a second-stage cold head; the coke-soup refrigeration circulation loop is divided into two paths, wherein one path is cooled by a cold head of the single-stage refrigerator and then enters the first-stage precooling heat exchanger; and the other path is sequentially cooled by a first-stage cold head and a second-stage cold head of the two-stage refrigerator and then enters the second-stage precooling heat exchanger. The energy efficiency ratio (COP) of the double-effect dilution refrigerating machine is two times that of an existing conventional dilution refrigerating machine, and vibration is small. And meanwhile, the problem that only the 4K cold source of the dilution refrigerator can be lifted and the 50K cold source cannot be lifted in the existing refrigeration technology is solved.

Description

Technical Field

[0001] The invention relates to the technical field of refrigeration equipment, and in particular to a large-cooling-capacity ultra-low-vibration dilution refrigerator. Background Art

[0002] With the development and application of quantum computing technology, the demand for dilution refrigerators is increasing. Domestic research institutes have the technical strength to develop dilution refrigerators and are moving towards industrialization.

[0003] At present, commercial dilution refrigerators generally use pulse tube refrigerators as cold sources, taking vibration and other factors into consideration. The maximum cooling capacity of a dilution refrigerator with a single pulse tube refrigerator as the cold source is 400uW@100mK, and the maximum cooling capacity of a dilution refrigerator with two pulse tube refrigerators as the cold source can reach 1000uW@100mK, which is also the current mainstream technical indicator of domestic commercial dilution refrigerators. Therefore, one of the main factors affecting the cooling capacity of existing dilution refrigerators depends on the number of cold sources (pulse tube refrigerators). The cooling capacity of the dilution refrigerator can be improved by increasing the number of cold sources. However, the increase in the number of pulse tube refrigerators will lead to an exponential increase in the volume, weight and electrical power of the main part of the dilution refrigerator, and will also bring about the negative effect of vibration superposition caused by the superposition of multiple pulse tube refrigerators. Summary of the invention

[0004] In order to solve the technical problems existing in the background technology, the present invention proposes a large cooling capacity and ultra-low vibration dilution refrigerator.

[0005] The present invention provides a large cooling capacity ultra-low vibration dilution refrigerator, comprising: A dilution refrigeration unit, comprising a dilution refrigeration circuit; the dilution refrigeration circuit is provided with a primary precooling heat exchanger and a secondary precooling heat exchanger located at a level below the primary precooling heat exchanger; A coke-soup refrigeration cycle unit, comprising a coke-soup refrigeration cycle loop, a single-stage refrigerator with a single cold head, and a double-stage refrigerator with a primary cold head and a secondary cold head; The coke-tang refrigeration cycle loop is divided into two routes, one of which is cooled by the cold head of the single-stage refrigerator and then enters the first-stage pre-cooling heat exchanger, and exchanges heat with the fluid from the dilution refrigeration circuit in the first-stage pre-cooling heat exchanger before flowing back to the coke-tang refrigeration cycle loop to form a branch circulation loop; the other route is cooled by the first-stage cold head and the second-stage cold head of the two-stage refrigerator in turn and then enters the second-stage pre-cooling heat exchanger, and exchanges heat with the fluid from the dilution refrigeration circuit in the second-stage pre-cooling heat exchanger before flowing back to the coke-tang refrigeration cycle loop to form a main circulation loop.

[0006] Preferably, the main circulation loop has a multi-stage heat exchanger, and the branch circulation loop is led out from the high-pressure side outlet end of the heat exchanger located at the first position in the main circulation loop and merged into the low-pressure side inlet end of the heat exchanger.

[0007] Preferably, the multi-stage heat exchanger includes a first-stage heat exchanger at the first stage, a second-stage heat exchanger located below the first-stage heat exchanger and installed on the first-stage cold head of a two-stage refrigerator, a third-stage heat exchanger located below the second-stage heat exchanger, a fourth-stage heat exchanger located below the third-stage heat exchanger and installed on the second-stage cold head of the two-stage refrigerator, and a last-stage heat exchanger at the last stage; the branch circulation loop is led out from the high-pressure side outlet end of the first-stage heat exchanger and merged into the low-pressure side inlet end of the first-stage heat exchanger.

[0008] Preferably, a regulating valve is provided in the branch circulation loop.

[0009] Preferably, the branch circulation loop comprises a branch heat exchanger installed on the cold head of the single-stage refrigerator.

[0010] Preferably, the main circulation loop includes a compressor, a throttle valve, and a high-pressure side pipeline that is led out from the outlet of the compressor and sequentially connects the high-pressure sides of the first-stage heat exchanger, the third-stage heat exchanger, and the final-stage heat exchanger in series and flows through the second-stage heat exchanger and the fourth-stage heat exchanger; and a low-pressure side pipeline that sequentially connects the low-pressure sides of the final-stage heat exchanger, the third-stage heat exchanger, and the first-stage heat exchanger in series and is introduced from the compressor inlet; and the end of the high-pressure side pipeline is connected to the low-pressure inlet end of the second-stage precooling heat exchanger through the throttle valve, and the inlet end of the low-pressure side pipeline is connected to the low-pressure outlet end of the second-stage precooling heat exchanger.

[0011] Preferably, the coke-soup refrigeration cycle unit is independently arranged outside the dilution refrigeration unit, and its main circulation loop, branch circulation loop and the primary precooling heat exchanger and secondary precooling heat exchanger in the dilution refrigeration loop are connected through vacuum low-temperature pipes.

[0012] Preferably, the vacuum cryogenic tube has four channels, and the four channels include two 50K channels and two 4K channels; one of the 4K channels connects the outlet of the main circulation loop with the low-pressure inlet of the secondary precooling heat exchanger, and the other 4K channel connects the low-pressure outlet of the secondary precooling heat exchanger with the inlet end of the main circulation loop to form a circulation between the main circulation loop and the secondary precooling heat exchanger; one of the 50K channels connects the outlet of the branch circulation loop with the low-pressure inlet of the primary precooling heat exchanger, and the other 50K channel connects the low-pressure outlet of the primary precooling heat exchanger with the inlet of the branch circulation loop to form a circulation between the branch circulation loop and the primary precooling heat exchanger.

[0013] Preferably, the two-stage refrigerator is a pulse tube refrigerator or a GM refrigerator.

[0014] Preferably, the single-stage refrigerator is a GM refrigerator.

[0015] The present invention adopts the coke-tang refrigeration cycle unit as the cold source of the dilution refrigerator, and the coke-tang refrigeration cycle unit in the present invention adopts the coke-tang refrigeration technology superimposed on the refrigerator refrigeration technology to complete the refrigeration cycle, so as to obtain a large-capacity dilution refrigerator with a refrigeration capacity that is twice that of the existing conventional dilution refrigerator. At the same time, since the dilution refrigeration unit is separated from the cold source, the cold dilution refrigeration unit is prevented from being affected by the vibration of the cold source, thereby achieving the purpose of low vibration. In addition, the refrigerator in the present invention includes a single-stage refrigerator and a two-stage refrigerator; the coke-tang refrigeration cycle loop is divided into two routes, one is a branch circulation loop, and the other is a main circulation loop. The branch circulation loop enters the primary pre-cooling heat exchanger of the dilution refrigeration loop after being cooled by the cold head of the single-stage refrigerator, and the main circulation loop enters the secondary pre-cooling heat exchanger of the dilution refrigeration loop after being cooled by the primary cold head and the secondary cold head of the two-stage refrigerator in turn. By adding a branch circulation loop and a single-stage refrigerator as a branch circulation loop cold source, a 50K cold source is provided for the dilution refrigerator to increase the cooling capacity of the 50K cold source of the dilution refrigerator, solving the problem that the existing refrigeration technology can only improve the 4K cold source of the dilution refrigerator, but the 50K cold source cannot be improved. In addition, the increase of the 50K cold source provided by the dilution refrigerator can greatly shorten the cooling time of the dilution refrigerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural schematic diagram of a large cooling capacity and ultra-low vibration dilution refrigerator proposed by the present invention. DETAILED DESCRIPTION

[0017] Reference Figure 1 The present invention provides a large cooling capacity ultra-low vibration dilution refrigerator, comprising: a dilution refrigeration unit 1 and a coke-soup refrigeration cycle unit 2 providing a cold source for the dilution refrigeration unit 1.

[0018] In this embodiment, the dilution refrigeration unit 1 includes a dilution refrigeration circuit; the dilution refrigeration circuit is provided with a primary precooling heat exchanger 11 and a secondary precooling heat exchanger 12 located at the next level of the primary precooling heat exchanger 11. 3 He and 4 After being pressurized by the compression vacuum pump in the dilution refrigeration circuit at room temperature, the He mixed gas enters the high-pressure side of the primary precooling heat exchanger 11 and is heated by the low-pressure side of the coke-soak refrigeration cycle unit 2. 4 He is cooled to 50K and then enters the high-pressure side of the secondary precooling heat exchanger 12 and is heated by the low-pressure side of the coke-soup refrigeration cycle. 4 He is cooled to 4 K. At this point, the refrigerant has completed the cooling of 4 K and enters the standard refrigeration cycle of the dilution refrigerator.

[0019] In this embodiment, the coke-soup refrigeration cycle unit 2 includes a coke-soup refrigeration cycle loop, a single-stage refrigerator 21 with a single cold head, and a double-stage refrigerator 22 with a primary cold head and a secondary cold head.

[0020] Specifically: the two-stage refrigerator 22 may be a GM refrigerator, a pulse tube refrigerator, or other types of refrigerators. In this embodiment, the two-stage refrigerator 22 is a GM refrigerator, the temperature of the first cold head is about 50K, and the temperature of the second cold head is about 10K. The single-stage refrigerator 21 is a GM refrigerator, and the temperature of the cold head of the single-stage refrigerator 21 is about 50K.

[0021] The coke-soup refrigeration cycle is divided into two routes, one of which is cooled by the cold head of the single-stage refrigerator 21 and then enters the primary precooling heat exchanger 11, and then exchanges heat with the fluid from the dilution refrigeration circuit in the primary precooling heat exchanger 11, and then flows back to the coke-soup refrigeration cycle to form a branch circulation loop 23. The other route is cooled by the primary cold head and the secondary cold head of the two-stage refrigerator 22 in turn, and then enters the secondary precooling heat exchanger 12, and then exchanges heat with the fluid from the dilution refrigeration circuit in the secondary precooling heat exchanger 12, and then flows back to the coke-soup refrigeration cycle to form a main circulation loop 24.

[0022] In this embodiment, the refrigeration temperature of the main circulation loop 24 is about 4K. The main circulation loop 24 includes a compressor 241, a throttle valve 242, a primary heat exchanger 243, a secondary heat exchanger 244 located below the primary heat exchanger 243 and installed on the primary cold head of the two-stage refrigerator 22, a tertiary heat exchanger 245 located below the secondary heat exchanger 244, a quaternary heat exchanger 246 located below the tertiary heat exchanger 245 and installed on the secondary cold head of the two-stage refrigerator 22, a final heat exchanger 247 located below the quaternary heat exchanger 246, and a heat exchanger 248 provided by the compressor 241. 1 and sequentially connect the high-pressure sides of the first-stage heat exchanger 243, the third-stage heat exchanger 245, and the final-stage heat exchanger 247 in series and flow through the high-pressure side pipelines of the second-stage heat exchanger 244 and the fourth-stage heat exchanger 246 and sequentially connect the low-pressure sides of the final-stage heat exchanger 247, the third-stage heat exchanger 245, and the first-stage heat exchanger 243 in series and are introduced into the low-pressure side pipeline from the inlet of the compressor 241; and the end of the high-pressure side pipeline is connected to the low-pressure inlet end of the second-stage precooling heat exchanger 12 through the throttle valve 242, and the inlet end of the low-pressure side pipeline is connected to the low-pressure outlet end of the second-stage precooling heat exchanger 12. During operation, the compressor 241 compresses and pressurizes the working medium helium and discharges it through the exhaust port. The normal temperature and high-pressure helium is precooled through the high-pressure side channel of the first-stage heat exchanger 243 and enters the second-stage heat exchanger 244 to exchange heat with the first-stage cold head in the two-stage refrigerator 22, so that the temperature of the working medium helium is reduced to about 50K. Then it enters the third-stage heat exchanger 245 in the next stage, and after heat exchange in the third-stage heat exchanger 245, it enters the fourth-stage heat exchanger 246 to exchange heat with the second-stage cold head in the two-stage refrigerator 22, so that the temperature of the working medium helium gas drops to about 10K. Then it passes through the high-pressure side channel of the final-stage heat exchanger 247 to be cooled, and is throttled to 4K normal-pressure helium gas through the throttle valve 242. The 4K normal-pressure helium gas is transported to the second-stage precooling heat exchanger 12 in the dilution refrigeration circuit, and flows out from the low-pressure side of the second-stage precooling heat exchanger 12, and then returns to the suction port of the compressor 241 through the low-pressure side channels of the final-stage heat exchanger 247, the third-stage heat exchanger 245, and the first-stage heat exchanger 243 in sequence, forming a closed circulation loop.

[0023] In this embodiment, the refrigeration temperature of the branch circulation loop 23 is about 50K. The branch circulation loop 23 is led out from the high-pressure side outlet end of the primary heat exchanger 243 and merged into the low-pressure side inlet end of the primary heat exchanger 243. A regulating valve 231 is provided in the branch circulation loop 23. During operation, the high-pressure room-temperature helium generated by the compressor 241 in the main circulation loop 24 is cooled by the primary heat exchanger 243, and then diverted to the branch circulation loop 23, and cooled to 50K by the single-stage refrigerator 21. The 50K helium is regulated in flow by the regulating valve 231 and transported to the low-pressure side of the primary precooling heat exchanger 11 in the dilution refrigeration loop. The helium is output from the low-pressure side of the primary precooling heat exchanger 11 and then returns to the low-pressure side inlet of the primary heat exchanger 243, forming a closed circulation loop. And the branch circulation loop 23 includes a branch heat exchanger installed on the cold head of the single-stage refrigerator 21.

[0024] The refrigeration principle of the present invention is: the refrigeration medium 4 He is pressurized to high-pressure gas by the compressor 241 in the main circulation loop 24 at room temperature, and then enters the high-pressure side of the primary heat exchanger 243, where it is cooled by the reflux helium gas on its low-pressure side and then divided into two paths. 4 He enters the secondary heat exchanger 244 installed at the first cold head of the two-stage refrigerator 22 and is cooled to 50K. It enters the high-pressure side of the third-stage heat exchanger 245 and is cooled by the helium gas refluxed from its low-pressure side. It then enters the fourth-stage heat exchanger 246 installed at the second cold head of the two-stage refrigerator 22 and is cooled to 10K. It then enters the high-pressure side of the final-stage heat exchanger 247 and is refluxed from its low-pressure side. 4 After cooling, He is throttled by throttle valve 242 to a 4K low-pressure gas-liquid mixed two-phase state 4 He; two phase 4 He enters the low-pressure side of the secondary precooling heat exchanger 12 of the dilution refrigeration circuit, absorbs the load heat and returns to the low-pressure side inlet of the final heat exchanger 247, passes through the final heat exchanger 247, the third-stage heat exchanger 245, and the low-pressure side of the first-stage heat exchanger 243 in sequence, absorbs the heat on their high-pressure sides to room temperature and returns to the suction port of the compressor 241, completing the refrigeration cycle. 4 He enters the branch heat exchanger installed at the cold head of the single-stage refrigerator 21 and is cooled to 50K by the cold head of the single-stage refrigerator 21. It enters the regulating valve 231 for flow regulation and then enters the low-pressure side of the primary precooling heat exchanger 11 of the dilution refrigeration circuit. After absorbing the load heat, it returns to the low-pressure side inlet of the primary heat exchanger 243 and the low-pressure side of the mainstream. 4 He flows through the low-pressure side of the primary heat exchanger 243 and returns to the suction port of the compressor 241. 4 The He refrigeration cycle provides the cold sources of 50K and 4K required for the operation of the dilution refrigerator host.

[0025] In this embodiment, the circulation flow of the branch circulation loop 23 can be increased by adjusting the valve 231 to increase the cooling capacity of the 50K cold source of the dilution refrigeration unit 1 during the cooling stage, thereby shortening the cooling time.

[0026] Taking the refrigeration capacity of 2000uW@100mK as an example, a conventional dilution refrigerator needs to integrate 4 pulse tube refrigerators as cold sources, with an input power of 48KW; to achieve the same indicator, the input power of the Jiao-Tang refrigeration cycle is 20KW, and the COP of its cold source part is more than twice that of the conventional one.

[0027] In this embodiment, the coke-tang refrigeration cycle unit 2 is independently arranged outside the dilution refrigeration unit 1, and the main circulation loop 24, the branch circulation loop 23 and the primary precooling heat exchanger 11 and the secondary precooling heat exchanger 12 in the dilution refrigeration loop are connected through the vacuum cryogenic pipe 3. The present invention adopts the split structural design of the coke-tang refrigeration cycle unit 2 and the dilution refrigeration unit 1, and the cold source of the dilution refrigerator is independent of the main unit. The two are connected by the vacuum cryogenic pipe 3, which effectively isolates the vibration influence generated when the cold source works.

[0028] Specifically: the vacuum low-temperature tube 3 has four channels, and the four channels include two 50K channels and two 4K channels; one of the 4K channels connects the outlet of the main circulation loop 24 and the low-pressure inlet of the secondary precooling heat exchanger 12, and the other 4K channel connects the low-pressure outlet of the secondary precooling heat exchanger 12 and the inlet of the main circulation loop 24 to form a circulation between the main circulation loop 24 and the secondary precooling heat exchanger 12; one of the 50K channels connects the outlet of the branch circulation loop 23 and the low-pressure inlet of the primary precooling heat exchanger 11, and the other 50K channel connects the low-pressure outlet of the primary precooling heat exchanger 11 and the inlet of the branch circulation loop 23 to form a circulation between the branch circulation loop 23 and the primary precooling heat exchanger 11.

[0029] As can be seen from the above, the present invention adopts the coke-soup refrigeration cycle unit 2 as the cold source of the dilution refrigerator, and the coke-soup refrigeration cycle unit 2 in the present invention adopts the coke-soup refrigeration technology superimposed on the refrigerator refrigeration technology to complete the refrigeration cycle, so as to obtain a large-capacity dilution refrigerator with a refrigeration capacity twice that of the existing conventional dilution refrigerator, and the COP is also twice that. At the same time, since the dilution refrigeration unit 1 is separated from the cold source, the cold dilution refrigeration unit 1 is prevented from being affected by the vibration of the cold source, thereby achieving the purpose of low vibration. In addition, the refrigerator in the present invention includes a single-stage refrigerator 21 and a two-stage refrigerator 22; the coke-soup refrigeration cycle loop is divided into two routes, one is a branch circulation loop 23, and the other is a main circulation loop 24. The branch circulation loop 23 enters the primary pre-cooling heat exchanger 11 of the dilution refrigeration loop after being cooled by the cold head of the single-stage refrigerator 21, and the main circulation loop 24 enters the secondary pre-cooling heat exchanger 12 of the dilution refrigeration loop after being cooled by the primary cold head and the secondary cold head of the two-stage refrigerator 22 in turn. By adding a branch circulation loop 23 and a single-stage refrigerator 21 as a cold source of the branch circulation loop 23, a 50K cold source is provided for the dilution refrigerator to increase the refrigeration capacity of the 50K cold source of the dilution refrigerator, thereby solving the problem that only the 4K cold source of the dilution refrigerator can be increased in the existing refrigeration technology, while the 50K cold source cannot be increased. In addition, the increase of the 50K cold source provided by the dilution refrigerator can greatly shorten the cooling time of the dilution refrigerator.

[0030] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A large cooling capacity ultra-low vibration dilution refrigerator, characterized in that: include: A dilution refrigeration unit (1) comprising a dilution refrigeration circuit, wherein the dilution refrigeration circuit is provided with a primary precooling heat exchanger (11) and a secondary precooling heat exchanger (12) located below the primary precooling heat exchanger (11); A coke-soak refrigeration cycle unit (2), comprising a coke-soak refrigeration cycle loop, a single-stage refrigerator (21) having a single cold head, and a double-stage refrigerator (22) having a primary cold head and a secondary cold head; The coke-soak refrigeration cycle loop is divided into two paths, one of which is cooled by the cold head of the single-stage refrigerator (21) and then enters the first-stage pre-cooling heat exchanger (11), and then exchanges heat with the fluid from the dilution refrigeration circuit in the first-stage pre-cooling heat exchanger (11) and then flows back to the coke-soak refrigeration cycle loop to form a branch circulation loop (23); the other path is cooled by the first-stage cold head and the second-stage cold head of the two-stage refrigerator (22) in sequence and then enters the second-stage pre-cooling heat exchanger (12), and then exchanges heat with the fluid from the dilution refrigeration circuit in the second-stage pre-cooling heat exchanger (12) and then flows back to the coke-soak refrigeration cycle loop to form a main circulation loop (24).

2. A large cooling capacity ultra-low vibration dilution refrigerator according to claim 1, characterized in that: The main circulation loop (24) has a multi-stage heat exchanger, and the branch circulation loop (23) is led out from the high-pressure side outlet end of the first heat exchanger in the main circulation loop (24) and merged into the low-pressure side inlet end of the heat exchanger.

3. A large cooling capacity ultra-low vibration dilution refrigerator according to claim 2, characterized in that: The multi-stage heat exchanger comprises a first-stage heat exchanger (243) at the first position, a second-stage heat exchanger (244) located below the first-stage heat exchanger (243) and installed on the first-stage cold head of the two-stage refrigerator (22), a third-stage heat exchanger (245) located below the second-stage heat exchanger (244), a fourth-stage heat exchanger (246) located below the third-stage heat exchanger (245) and installed on the second-stage cold head of the two-stage refrigerator (22), and a final-stage heat exchanger (247) at the final stage; the branch circulation loop (23) is led out from the high-pressure side outlet end of the first-stage heat exchanger (243) and merged into the low-pressure side inlet end of the first-stage heat exchanger (243).

4. The large cooling capacity ultra-low vibration dilution refrigerator according to claim 1, characterized in that: A regulating valve (231) is provided in the branch circulation loop (23).

5. According to the large cooling capacity and ultra-low vibration dilution refrigerator of claim 1, the branch circulation loop (23) comprises a branch heat exchanger installed on the cold head of the single-stage refrigerator (21).

6. The large cooling capacity ultra-low vibration dilution refrigerator according to claim 3, characterized in that: The main circulation loop (24) comprises a compressor (241), a throttle valve (242), a high-pressure side pipeline which is led out from the outlet of the compressor (241) and sequentially connects the high-pressure sides of the first-stage heat exchanger (243), the third-stage heat exchanger (245), and the final-stage heat exchanger (247) in series and flows through the second-stage heat exchanger (244) and the fourth-stage heat exchanger (246), and a low-pressure side pipeline which sequentially connects the low-pressure sides of the final-stage heat exchanger (247), the third-stage heat exchanger (245), and the first-stage heat exchanger (243) in series and is led from the inlet of the compressor (241); and the end of the high-pressure side pipeline is connected to the low-pressure inlet end of the second-stage precooling heat exchanger (12) through the throttle valve (242), and the inlet end of the low-pressure side pipeline is connected to the low-pressure outlet end of the second-stage precooling heat exchanger (12).

7. A large cooling capacity ultra-low vibration dilution refrigerator according to any one of claims 1-6, characterized in that: The coke-soup refrigeration cycle unit (2) is independently arranged outside the dilution refrigeration unit (1), and its main circulation loop (24), branch circulation loop (23) are connected to the primary precooling heat exchanger (11) and the secondary precooling heat exchanger (12) in the dilution refrigeration loop through a vacuum low-temperature pipe (3).

8. The large cooling capacity ultra-low vibration dilution refrigerator according to claim 7, characterized in that: The vacuum cryogenic tube (3) has four channels, the four channels including two 50K channels and two 4K channels; one of the 4K channels connects the outlet of the main circulation loop (24) and the low-pressure inlet of the secondary precooling heat exchanger (12), and the other 4K channel connects the low-pressure outlet of the secondary precooling heat exchanger (12) and the inlet of the main circulation loop (24) to form a circulation between the main circulation loop (24) and the secondary precooling heat exchanger (12); one of the 50K channels connects the outlet of the branch circulation loop (23) and the low-pressure inlet of the primary precooling heat exchanger (11), and the other 50K channel connects the low-pressure outlet of the primary precooling heat exchanger (11) and the inlet of the branch circulation loop (23) to form a circulation between the branch circulation loop (23) and the primary precooling heat exchanger (11).

9. The large cooling capacity ultra-low vibration dilution refrigerator according to claim 1, characterized in that: The two-stage refrigerator (22) is a pulse tube refrigerator or a GM refrigerator.

10. The large cooling capacity ultra-low vibration dilution refrigerator according to claim 1, characterized in that: The single-stage refrigerator (21) is a GM refrigerator.

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