| 摘要 |
1,075,316. Refrigerating. UNITED KING- DOM ATOMIC ENERGY AUTHORITY. Feb. 4, 1966 [Feb. 24, 1965], No. 8035/65. Heading F4H. A cryogenic device comprises a vessel 1 having a cold surface 2 and containing a cryogenic liquid at a predetermined temperature, an intermediate vessel 10 in communication with vessel 1 through duct 11, a connection 16 for supplying cryogenic liquid from a dewar vessel 3 to the vessel 10 and a valve 12 in the latter for opening the duct 11 only when the temperature of the liquid in vessel 10 is substantially the same as that of the liquid in vessel 1. Vessels 10, 1 and 3 have respective vapour outlets 14, 15, 23 which are each connectable to a common vapour pump (20, Fig. 2, not shown), via a set of three valves (VT1-3, VC1-3 or VD1-3) of progressively decreasing aperture, the valves being controlled by relays energized in response to signals from contacts disposed at different levels in the legs of manometers (Fig. 3, not shown) connected to the respective vessels. Thermometers T 1 and T 2 define the maximum and minimum level of liquid in vessel 1 and a thermometer T 3 is provided to detect the presence of a predetermined level of liquid in vessel 10. The pressures and temperatures within the vessels, the transfer of liquid from vessel 3 to vessel 10 and the transfer of liquid from vessel 10 to vessel 1 are controlled automatically by a logic circuit (Fig. 5, not shown) in response to signals from the pressure and temperature-sensing means. Surface 2 preferably comprises a condensing surface of a cryopump and vessel 1 is surrounded by a heat shield 7 which is an extension of a double-walled lliquid nitrogen containing vessel 8. The cryogenic liquid is preferably helium. |
