GB821905A - Storing and dispensing low boiling liquefied gases - Google Patents

Abstract

821,905. Storing liquefied gases; forcing liquid by gaseous pressure. UNION CARBIDE CORPORATION. July 23, 1957 [July 24, 1956], No. 23238/57. Classes 8(2) and 102(2). A double-walled heat insulated vessel 31, 32, Fig. 2, for storing liquefied gas, e.g. hydrocarbon having a boiling point below 230‹K. at atmospheric pressure is initially charged through a duct 50 with liquid at a temperature at least equal to the boiling point at the minimum service pressure whereby the vapour and liquid occupying spaces G, L are in a state of equilibrium and liquid is forced by the pressure of its own vapour through a duct 54 and a vaporizing coil 63 to a gas service outlet 53 controlled by a manual valve 71 ; the pressure of the vapour in space G being maintained during discharge periods solely by heat leak through the insulation 33. The liquid discharge duct 54 leads to a passage 51 having a transverse bore 55 controlled by an automatic valve 57 responsive to a predetermined pressure rise in space G to connect the latter to the coil 63 and gas outlet 53 and in which event liquid ceases to be forced out. The outlet 53 has a vent valve 74 and the head 35 of the vessel has a safety disc 76, Fig. 6 (not shown). The vaporizing coil comprises a down tube 65 discharging through a plurality of apertures therein into one end of a manifold 64 having its other end connected to the inlet end of the coil 63. The inner vessel 31 is suspended by its neck 36 from the head 35 of the outer vessel 32 and is centred at its base by a tube 39 telescoping into an upstanding internal flange. The evacuated insulation space is charged with silica powder mixed with heat absorbing and reflecting particles and the heat leak is transmitted to the liquid by radial metal plates 83 within the space L. Discharge of liquefied gas is effected by removing a plug 84, Fig. 7 (not shown), from the end of passage 51. In a modification the automatic back pressure release valve connecting the space G with the passage 51b, Fig. 9, is replaced by a capillary coil 104, Fig. 11, of such resistance as to allow a limited but continuous withdrawal of gas from space G simultaneously with the forcing of liquid from the space L. In this construction the evacuated insulation space between the vertical walls of the vessels 31a, 32a is charged with layers of heat reflecting metal foil spaced by layers of fibre glass whereas the top and bottom spaces are charged with silica powder. Also the vaporizing coil 52a is located between the top of the outer vessel 32a and a surrounding dome 107.