Neon-helium refrigerator

To construct economical facilities of preliminary cooling a neon-helium refrigerator is designed and produced in Which a generator gas (helium) is successively cooled at three temperature levels - 78 K, 64 K and 28 K. The first two levels are ensUred by liquid nitrogen, and the third one by a throttle neon refrigerator of 400 W cooling capacity at the 28 K level, at the 45 m3/h neon compressor capacity. The rig trials of the refrigerator were carried out. Its real cooling capacity was 270 W while working with a compressor at the 31 m3/h capacity. This fact is in good agreement with the calculations taking into account that the practical neon compressor capacity is less than the calculated one. The refrigerator efficiency depending on the cooling object temperature is calculated. The optimal cooling conditions are determined from the power point of view. The dynamics of object cooling is considered. It is shown that when utilizing multi-stage cooling of cryogenic objects it is necessary to determine optimal temperatures of transition from one cooling stage to another, that permits to minimize expenditure of energy during cooling process