| 摘要 |
1,065,776. Refrigerating. A. D. LITTLE Inc. July 1, 1964 [Aug. 16. 1963], No. 27253/64. Heading F4H. [Also in Division F1] A closed cycle refrigerating machine comprises first and second displacers operable on a fluid in a housing and defining a warm volume, an intermediate temperature volume and a cold volume therein, the ratio of the cold volume to the warm volume being no greater than where Tw, Ti and Tc are the temperatures in degrees K. of the fluid in the warm, intermediate and cold volumes respectively. As shown in Fig. 3a the machine comprises a displacer 30 movable in housings 23 and 17 to define warm volumes 10 and 11 which are interconnected by ducts 70, 71 and 73 in the lower portion of the displacer which is reciprocated by a crank 48. Volume 10 communicates via a passage 78 with a first cooler 80 which is in turn connected by a tube 75 to a first regenerator 88 in the interior of displacer 30. Regenerator 88 communicates through a tube 93 with a second cooler 94 (Fig. 3b) which is in communication with an intermediate volume 12 formed at the top of displacer 30 and with a second regenerator 122, the latter being connected to a cold space 14 defined by a displacer 44 operating in a cylinder 26. Displacer 44 is driven in the upward direction through a shaft 36 extending through displacer 30 by a crank 56 (Fig. 3d) and is moved downwardly by a spring 63. Intermediate volume 12 and cooler 94 are cooled by liquid nitrogen flowing successively through coils 106 and 115. The machine is mounted in a wall 20 of an enclosure with the warm end of the machine exposed to ambient conditions external of the enclosure which may be a cryopurnp (see Division F1). The cold displacer may be stepped to define a plurality of cold spaces operating at different temperatures (Fig. 6, not shown). The cycle performed by the machine approximates to one in which: (i) gas is transferred from the intermediate to the warm volume by upward movement of the warm displacer, (ii) the remaining gas in the intermediate volume is transferred to the cold volume by downward movement of the cold displacer, (iii) gas is returned from the warm to the intermediate volume and (iv) gas is returned from the cold to the intermediate volume. |
