Expansion piston for filling of carbon dioxide

Abstract

An expansion piston for filling of carbon dioxide comprises an expansion piston shell. One end of the shell is provided with an expansion piston end cover. An expansion piston cavity is formed in the shell and filled with carbon dioxide. The other end of the shell is provided with a mounting hole. An expansion piston connecting rod is arranged in the mounting hole. A flat washer is arranged at the end, going into the expansion piston cavity, of the expansion piston connecting rod. A nut is arranged on the outer side of the flat washer. A spring washer is arranged between the nut and the flat washer. The expansion piston end cover and the expansion piston shell are connected through threads. The inner surface of the expansion piston end cover is provided with a plurality of grooves which are of a concentric annulus structure. When the expansion piston is used for a Stirling low-temperature refrigerator, carbon dioxide can be frozen into dry ice at low temperature and gathers in the grooves of the expansion piston end cover, so that vacuum is formed in the expansion piston, natural convection heat transfer in the piston is weakened, and axial heat conduction loss of the expansion piston is effectively reduced.

Description

technical field [0001] The invention belongs to the mechanical field and relates to a piston, in particular to an expansion piston used in a Stirling cryogenic refrigerator. Background technique [0002] The expansion piston is one of the two moving parts of the Stirling refrigerator. When it reciprocates in the expansion chamber, the temperature at the cold end of the expansion piston is relatively low, while the temperature at the hot end is relatively high. The temperature difference between the hot and cold ends is more than 200°C. The huge temperature difference will inevitably lead to heat transfer loss. The heat from the high temperature side is transferred to the low temperature side, which leads to the loss of cooling capacity of the refrigerator and reduces the efficiency of the refrigerator. [0003] Chinese patent, patent number: CN104534718A, which discloses a hollow ejector for a Stirling refrigerator and its vacuum pumping device. The air in the hollow ejector...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the above-mentioned technical problems in the prior art, the present invention provides an expansion piston filled with carbon dioxide. The expansion piston filled with carbon dioxide is to solve the cooling capacity loss of the refrigerator caused by the expansion piston in the prior art. , the technical problem that the efficiency of the refrigerator is reduced

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