4KG-M制冷机做冷源的自循环氦液化装置研制

采用5台1.5W/4.2KG-M制冷机(日本住友RDK415D)并联研制出了1台方便实验室使用的小型氦液化装置,并为其建立了性能测量实验台。实验结果表明:液氦温度为4.17K(饱和压力为96kPa)时,氦液化率为74L/d;液氦温度为4.42K(饱和压力为121kPa)时,液化率为116L/d,经拟合,在4.2K(饱和压力为100kPa)时液化率为83L/d,并且通过100小时以上的连续运行,说明该氦液化装置自循环性能良好。通过实验发现:实测氦液化率远大于制冷机冷头制冷量对应的计算氦液化率。分析认为:G-M制冷机气缸壁对氦气预冷是提高实际氦液化率的主要因素。

Development of helium liquefaction self-circulation system with 4 K G-M cryocoolers

A helium liquefaction system using five parallel 1.5 W/4.2 K G-M cryocoolers and its performance test device were described. Liquefaction rates at several temperatures have obtained as 74 L/d at 4.17 K (saturation pressure is 96 kPa) and of 116L/d at 4.42 K(saturation pressure is 121 kPa). It is obvious that the liquefaction rate of 83 L/d at 4.2 K (100 kPa) can be gotten by curve fitting and the feasibility of self-circulation was certified through more than 100 hours running. It is found that the real liquefaction rate by experiment is more than the value calculated according to the cooling capacity of cryocoolers. The results show that the major factor comes from precooling of the cylinder wall of G-M cryocoolers.