Two stage Gifford-McMahon cycle cryorefrigerator operating at 20 K

摘要: A two stage Gifford-McMahon cycle cryorefrigerator operating at 20 K is described. This refrigerator uses a very simple ‘spool valve’ and modified indigenous compressor to compress helium gas. reaches lowest temperature of 15.5 K; it takes ≈ 50 min reach the cooling capacity 2.5 W 25 K. The cool-down characteristics load are presented in graphical form. effect changing pressure ratio second regenerator matrix size also reported. Pressure-volume (P-V) diagrams obtained various temperatures indicate that P-V losses form major fraction total this becomes more pronounced as decreased. heat balance analysis shows relative magnitudes losses.