Labyrinth seal piston for G-M refrigerator

Abstract

The invention relates to a labyrinth seal piston for a G-M refrigerator in the technical field of mechanical pistons. The piston is positioned inside a cylinder of the refrigerator and driven by a motor to move inside the cylinder in a reciprocating way and has a cylindrical structure; the piston is integrally made of the same material as that of the cylinder of the refrigerator or a material of which the thermal shrinkage at a low temperature is lower than that of the material of the cylinder; the outer surface of the piston is provided with a plurality of seal grooves which are vertical to the axle center of a cylinder; and a polyfluortetraethylene wear-resistant coating is formed outside the entire piston. The sealing performance, running stability and reliability of the G-M refrigerator can be improved effectively and the service life can be prolonged effectively.

Description

technical field [0001] The invention relates to a device in the technical field of piston sealing, in particular to a labyrinth-sealed piston used in a G-M refrigerator. Background technique [0002] In recent years, with the rapid development of large cryogenic vacuum pumps, high and low temperature superconducting devices, nuclear magnetic resonance imaging (MRI), infrared detectors, and low temperature optoelectronic devices, the industrial demand for large cooling capacity refrigerators is also growing. The G-M refrigerator with large cooling capacity has become an important research direction in the field of cryogenic refrigerators. For the two-stage G-M refrigerator, the piston ring sealing method is used between the two-stage piston and the cylinder in the traditional structure. This method has high requirements for the material and processing accuracy of the piston ring and its expansion ring, and there is wear between the piston ring and the cylinder. , long-term o...

AI Technical Summary

Problems solved by technology

In the above-mentioned patent, both the cylinder body and the piston are engraved with sealing grooves, the structure is complicated, and the processing difficulty is increased, and the labyrinth sealing structure is mainly used in the piston compressor, while in the G-M refrigerator, the piston not only plays the role of compressing and expanding the gas, At the same time, it is filled with cold storage material inside, which acts as a regenerator, and there is no problem of oil return. Therefore, both the working principle of the piston and the working temperature range are quite different from the traditional piston compressor.

Images