Abstract 921,853. Storing liquefied gases. CHICAGO BRIDGE & IRON CO. Sept. 20, 1961 [Feb. 8, 1961], No. 33616/61. Class 8(2). A double walled storage tank comprises a vessel 10 of steel suitable for use at low temperatures and containing liquefied gas, and surrounding a vessel 11 of steel, from which an accumulator 19, which may have a filter screen 22, depends to receive leakage liquid from the vessel 10 and discharge it to atmosphere through a poppet relief valve 24. The accumulator 19 may be vertically depending tube closed by a spring-loaded poppet valve or by a synthetic rubber or plastic diaphragm, frangible by contact with low temperature liquid. Between the vessels is thermal insulation material e.g. perlite and an inert gas may be used to replace any air within the space. Specification 840,952 is referred to.