Heat insulating wall construction for a low temperature liquefied gas tank of the membrane type

Claim 1

In a low temperature liquefied-gas tank of the membrane type, a heat insulating wall structure, said structure comprising a framework constituted of support members formed of a load supporting and heat insulating material, said framework defining a thickness of the heat insulating wall structure having the spaces formed adapted to be filled with a heat insulating material, and a plate member fastened to and extending over the framework to define an inner surface of the heat insulating wall structure, said framework forming a network comprising a plurality of contiguously arranged flush surfaces, said plate member comprising a plurality of contiguous first plate elements each being supported along at least portions of its periphery by said surfaces, a plurality of contiguous second plate elements being superimposed on said first plate elements in close surface contact therewith, the joints between contiguous of said second plate elements being offset relative to the joints between contiguous of said first plate elements, said framework being substantially constituted of said network, including support members extending between a wall of a rigid outer vessel and said network substantially perpendicularly to said wall and said network, said network being composed of a first group of parallel extending beams, a second group of parallel extending beams smaller than said first beams, said second beams being arranged to extend perpendicularly to said first beams, said support members being connected with said first group of beams at portions where said first and second beams cross each, and reinforcing joint plates being fastened to and bridging said support members and said first group of beams.