G-m refrigerator with phase modulation mechanism

Abstract

A G-M refrigerator comprises a compressor (1), a gas inlet valve (2), an exhaust valve (3), a regenerator (4), a cylinder (5), a piston (6), a hot cavity (7), a cold cavity (8), a seal ring (9), a driving mechanism (10-12), an annular gap (13), a heat exchanger (14), an orifice valve (18) and a gas reservoir (19). By introducing a phase modulation mechanism, such as the orifice valve (18), the gas reservoir (19) and the like, the working way of gas in the annular gap (13) is changed to be the same with that of a pulse tube refrigerator with the phase modulation mechanism, expansion of the part of the gas is fully utilized for doing work so as to generate the cold effect, loss caused by gas leakage through the seal ring (9) is further eliminated and the performances of the G-M refrigerator are further improved.

Description

FIELD OF THE INVENTION[0001]The invention relates to a cryogenic refrigerator, particularly relates to a regenerative cryogenic refrigerator and specifically relates to a G-M refrigerator with a phase modulation mechanism.BACKGROUND OF THE INVENTION[0002]G-M refrigeration cycle was jointly invented by Gifford and Mcmahon, and the principle of the G-M refrigeration cycle is to utilize deflation of heat insulation gas for refrigeration. At present, a G-M refrigerator has been widely applied in cryogenic pumps and cooling of a variety of superconducting magnets. When in application, a cold head of the refrigerator is generally used for direct contact or a material with high heat conductivity is used as a heat bridge for realizing the cooling effect.[0003]At present, a gap exists between the cylinder wall and the piston of the G-M refrigerator which is widely used, pressure in the refrigerator changes periodically and the gap can cause pump gas loss. Seal rings are arranged at the hot e...

AI Technical Summary

Benefits of technology

[0010]The phase modulation mechanism is an orifice gas reservoir structure communicated with the hot end of the cylinder or a two-way gas inlet mechanism or a four-valve mechanism or other phase modulation mechanisms which are more effective.

[0014]By introducing the phase modulation mechanism, the working process of the gas in the annular gap is changed, the expansion of the part of the gas is fully utilized for doing work, the loss of the gas leakage through the seal ring is further prevented and the G-M refrigerator can further obtain better performances.

Problems solved by technology

At present, a gap exists between the cylinder wall and the piston of the G-M refrigerator which is widely used, pressure in the refrigerator changes periodically and the gap can cause pump gas loss.

In addition, the seal rings can move in the cylinder along with the piston in a reciprocating manner, the sealing between the seal ring and the cylinder, as well as between the seal ring and the piston is non-tight, the high-temperature gas in a hot cavity can be leaked to the cold cavity through the seal rings and the low-temperature gas in the cold cavity can be leaked to the hot cavity through the seal rings, which cause the loss of the cold energy, namely the loss of gas leakage.

Along with the increase in operation time of the refrigerator, abrasion of the seal rings will become serious gradually, the sealing between the seal ring and the cylinder, as well as between the seal ring and the piston will become more and more loose, the gas leakage amount through the seal rings will be more and more and the generated loss of the cold energy will also be more and more.

In addition, friction heat generated by sliding sealing of the seal rings in the cylinder can also cause the loss of the cold energy.

The loss of the cold energy seriously affects the performances of the refrigerator, thereby being difficult to meet testing and application requirements of low-temperature superconducting.

Images