GB1227033A - - Google Patents

Abstract

1,227,033. Liquefied gas storage containers. GAZ DE FRANCE, and GAZ-TRANSPORT 19 June, 1968 [21 June, 1967], No. 29295/68. Heading F4P. Pre-stressed cables located within a concrete skirt 31, Fig. 1, of an L.N.G. container having a flat concrete base 32, a domed concrete roof 33 and a heat insulating lining 34, 35 for said skirt and base and which is itself lined internally by a fluid tight barrier layer 61, Fig. 3, are made of cryogenic steel of the austenitic type and are such that the yield strength at the low temperature of the stored gas is greater than the total stress to which each cable is subjected by hydrostatic force exerted by the L.N.G. and by thermal stress occasioned by rupture of the barrier and flooding of the insulation layers 34, 35. The latter are formed by a plurality of boxed frames 51, 47, 48, Fig. 7, having apertured cells filled with perlite through which inert gas may circulate. Each box frame 51 is secured to the concrete skirt by steel rods 52 embedded therein; the wedge-shaped space 59 between adjacent frames being filled with rock wool. The inner face of each side frame 51 is covered by a nickel steel plate e.g. 61, Fig. 5, having an inwardly extending edge flange 63 which is welded to a steel strip 65 secured between adjacent frames 51 and extending the height of the skirt. The strip 65 is also welded to the edge flange 64 of the plate 62 of the adjacent frame thus forming the barrier layer. The frame 47 on the base 32 are similarly lined with steel plates welded together at their edges forming a barrier 79, Fig. 10, which is connected to the vertical barrier 78 by an expansion joint formed by a corrugation 89, L-sectioned bars 97 and brackets 92 fixed by tubes 91 to the concrete skirt 31. The bottom of skirt 31 carries an annular steel plate 82 having a corrugated portion 84 and which is slidably supported on an annular steel plate 80 secured to the bed 32; and the inner periphery of the two plates 80, 82 being welded together. The concrete roof 33 is separated from the liquid charge by a ceiling 40, Fig. 15, suspended by cables 39 and formed of a framework of crossed beams on which are laid bags of perlite 43. Filling and emptying ducts 104, 105, Fig. 11, extend through the concrete base 32 to a conduit 204 and a valve 122, and at the upper inner end of each duct 104, 105 is a weighted closure member 131, 125 suspended by cables 130, 126 whereby the ducts can be closed independently of the valve 122. The upper end of the pervious insulation layer 34 is normally left open but may be closed by a packing 141 when it is desired to evacuate or pressurize the cellular insulation to detect leaks in the barrier.