Gifford-McMahon 冷凍機の2 段目蓄冷器内に挿入された ベークライト棒の効果

Abstract

A novel regenerator structure for a two-stage Gifford-McMahon (GM) cryocooler is introduced in this paper. The structure has a bakelite rod inserted in the co-axial layout of the 2nd stage regenerator in which lead (Pb) spheres are filled as the regenerator material. Inserting the bakelite rod reduces the Pb weight, leading to a decrease in the heat capacity of the regenerator. To clarify the effect of the bakelite rod, two types of conventional GM cryocoolers with power consumption of 1.3 and 7.3 kW, respectively, are tested at the operating frequency of 1.2 Hz. From the experimental results, the lowest attainable temperature of the 2nd stage rises slightly as a result of reducing the Pb weight which is adjusted by the volume of bakelite rod. However, a reduction of Pb weight by approximately 40% does not affect the deterioration of the cooling power at above 9 K. These two GM cryocooler models show almost the same characteristics. Thus, this novel regenerator structure may be applied to most two-stage GM cryocoolers.