Pre-cooling device of superfluid helium system

Abstract

The embodiment of the invention provides a precooling device of a superfluid helium system. The precooling device comprises a vacuum cover, a refrigerating machine, a heat exchanger, a condenser, a superfluid helium cavity, a low-temperature throttling valve and a mechanical thermal switch. The refrigerating machine is provided with a first-stage cold head and a second-stage cold head, and the first-stage cold head and the second-stage cold head are both located in the vacuum cavity of the vacuum cover. The first-stage cold head is connected with the heat exchanger, the second-stage cold head is connected with the condenser, and the low-temperature throttling valve is connected with the condenser and the superfluid helium cavity, so that liquid helium is converted into superfluid helium. The mechanical thermal switch is inserted in the vacuum cover in a lifting mode, one end of the mechanical thermal switch penetrates into an inner cavity of the vacuum cover and extends to the superfluid helium cavity, a heat conduction flange is arranged at the lower end of the mechanical thermal switch, and the heat conduction flange can make contact with or be separated from the superfluid helium cavity. The heat conduction flange is connected with the first-stage cold head through a heat conduction piece so as to transmit the cooling capacity of the first-stage cold head to the heat conduction flange. The precooling device can greatly shorten the precooling time of the superfluid helium system.

Description

technical field [0001] The invention relates to the technical field of cryogenic cooling, in particular to a precooling device for a superfluid helium system. Background technique [0002] Low temperature environment is very important for some large scientific projects. Large-scale scientific projects such as particle cyclotrons and thermonuclear fusion experimental reactors require extremely low temperatures to cool some important internal components in order to achieve the desired effect. In addition, in low temperature environments, some materials will exhibit completely different properties than those at normal temperature. For example, stainless steel will be magnetized, and superconducting materials will achieve superconductivity when they reach their low-temperature transition temperature. At the same time, the properties testing of some special materials at low temperature requires the construction of a corresponding low temperature system. [0003] Directly immer...

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Problems solved by technology

[0005] An embodiment of the present invention provides a precooling device for a superfluid helium system, which is used to solve the problem that the precooling time is too long when the superfluid helium system is precooled by a refrigerator in the prior art

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