Double-coil pipe cold steam refrigerating low-loss liquid helium Dewar

Abstract

The invention relates to a low-loss liquid helium Dewar for the refrigeration of the cold vapor of double pipe coils, belonging to the liquid helium Dewar. The low-loss liquid helium Dewar comprises a shell, a liner, a bottleneck, a cold screen, a first helium outlet tube and a second helium outlet tube, wherein the liner is arranged in the shell, both ends of the bottleneck are respectively connected to the top of the liner and the top of the shell, the inner part of the liner is communicated with the outer part of the shell through the bottleneck, the first helium outlet tube is coiled on the bottleneck, both ends of the first helium outlet tube are communicated with the inner part of the liner and the outer part of the shell, the liner is covered by the cold screen, the second helium outlet tube is coiled on the cold screen, both ends of the second helium outlet tube are communicated with the inner part of the liner and the outer part of the shell, and vacuum exists between the outer part of the liner and the inner surface of the shell. The bottleneck can extend from the top of the liner to the bottom of the liner and be hermetically connected with the bottom of the liner, and the bottleneck can be made by a ripple tube. The invention uses two helium outlet tubes to nicely improve the cooling of the cold screen and the bottleneck and reduce the evaporation rate of helium. The flow quantity of both helium outlet tubes can be independently controlled, the best velocity ratio can be adjusted according to actual situation to obtain the best cooling effect without complex and unreliable self-consistent calculation.

Description

technical field [0001] The invention relates to a liquid helium dewar, in particular to a low-loss liquid helium dewar with double-coil cold vapor refrigeration. Background technique [0002] The purpose of the liquid helium dewar is to (1) store liquid helium for a long time and (2) provide a low temperature environment for a long time for scientific experiments. Both of these points require the helium evaporation rate of the liquid helium Dewar to be at a low level. With the advancement of science, especially the improvement of nano-microscopic science and technology, there are new requirements for liquid helium Dewar, namely (3) extremely low vibration to ensure that precision experiments in Dewar are not disturbed by vibration . Reducing the Dewar's helium evaporation rate also helps reduce Dewar vibration. [0003] The existing technologies for reducing the helium evaporation rate of liquid helium Dewar mainly include the following types: (1) Precooling the outer Dew...

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Problems solved by technology

[0005] In order to solve the defect that the existing liquid helium Dewar cold shield technology cannot take into account radiation heat leakage and conduction heat leakage well, a double-coil cold vapor refrigeration system that can better balance radiation heat leakage and conduction heat leakage is manufactured. Low Loss Liquid Helium Dewar

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