| 摘要 |
1483356 Refrigerating PHILIPS GLOEILAMPENFABRIEKEN NV 6 Sept 1974 [11 Sept 1973] 39061/74 Heading F4H In a cryogenic refrigerator having a displacer 2 and piston 3 arranged to reciprocate with a phase difference and defining a compression space 6 and expansion space 8, a cooling unit 7 and a main regenerator 11 incorporated in a duct 10 and containing for example, lead balls; an auxiliary regenerator is connected in parallel with the main regenerator 11 and is formed by the annular gap between the displacer 2 and the cylinder 1a. The walls 2b of the displacer and the cylinder wall la are of stainless steel. The working medium is preferably helium. The hydraulic diameter d h of the annular gap satisfies the relation: where s=stroke length of the displacer 2; #= mean dynamic viscosity of the working medium flowing through the gap during operation of the refrigerator; L = length of the gap in the axial direction; #=mean density of the working medium flowing through the gap during operation of the refrigerator; ##=mean pressure drop through the main regenerator 11. |
