Experimental investigation of the JT valveless 4K JT refrigerator
李 遠鑑, 朱 紹偉 （同済大）
Abstract:As a mature refrigeration technology with over a century of development, 4K JT refrigerators still has intrinsic low reliability problem due to flow blockage risks caused by solidified impurity. The JT valveless 4K JT refrigerator can solve this problem theoretically by utilizing the unique thermodynamic properties of helium near its critical point, in which throttling function is coupled with high-pressure channels of the last stage counterflow heat exchanger without JT valve. A JT valveless 4K JT refrigerator precooled by a 4K GM refrigerator with helium bottle as gas source was made and tested. It demonstrated 0.28W of cooling capacity at 4.9K with 1.4MPa of high pressure and 8K precooling temperature. The high pressure and precooling temperature influences were also investigated. It is confirmed that JT valveless 4K JT refrigerator can work well.