| 摘要 |
914,193. Storing liquefied gases. CHICAGO BRIDGE & IRON CO. Oct. 27, 1960 [Feb. 19, 1960], No. 36841/60. Class 8(2). A cryogenic liquid storage tank 10 comprises an inner storage vessel 16 in which is stored a first cryogenic liquid L, an intermediate -vessel 13 surrounding and spaced from the vessel 16 to define a storage space in which is stored a second cryogenic liquid R, and an outer shell 11 surrounding and thermally insulated from the vessel 13, the liquid R being selected to have the lower boiling temperature of the two liquids and being held at substantially the same or at a greater level than the liquid L to maintain the temperature of the latter below its boiling temperature. As described, the liquids L and R are respectively liquefied oxygen and liquefied nitrogen. The tank 10 is spherical and the outer shell 11 is thermally insulated from the vessel 13 by material such as expanded perlite, rock-wool, cork or fibre-glass and/or by a vacuum. The tank 10 is supported on a plurality of columns 12 and the vessels 16 and 13 are supported by straps or bars 18 and 14, respectively. The liquid gases L and R are normally stored at atmospheric pressure and any gas which boils off from the refrigerant R may be vented to the outside atmosphere through a duct 23 or be circulated through a gas liquefaction unit 24 and returned to the vessel 13 through a duct 25 and inlet means 27. A heat exchanger 19 is disposed in the space between the vessels 16 and 13 and is used to cool a gas such as helium so that the latter may be used for the pressure transfer of the liquid gas L from the vessel 16 to its point of use; the gas used in the pressure transfer may, however, be cooled elsewhere in which case the heat exchanger 19 is dispensed with. The liquid gases L and R may be stored at superatmospheric or subatmospheric pressures. The inner vessel 16 and its supports 18 may be made of aluminium, stainless steel or nickel steel alloys.- Various tank accessories may be used therewith, e.g., manholes, flexible couplers, valves, pumps and systems for emptying and filling the vessels 16 and 13. In a second embodiment, Fig. 2 (not shown), a vertical cylindrical tank has dished ends; alternatively, the ends may be flat or the roof end may be coned. In a third embodiment, Fig. 3 (not shown), a horizontal cylindrical tank has associated therewith a heat exchanger which is external to the tank and through which is circulated the liquid gas refrigerant for cooling of the latter. In a fourth embodiment, Fig. 4 (not shown), a sphercial tank has an outer shell supported on tubular columns and an intermediate vessel supported on tubular columns disposed within the columns for the shell. |
