Liquid storage pit with floating cover

Claim 1

Apparatus for storing liquids comprising: means defining a liquid storage pit having an inclined wall; and expandable floating cover substantially overlying said pit, said cover comprising a central portion and an outer portion, said central portiOn comprising a pipe framework operatively connected to slabs of buoyant material to form a fluidtight cover for the central portion of said storage pit, said outer portion comprising a plurality of buoyant elements and a plurality of thin flexible fluidtight sheets movably interconnecting said buoyant elements in a fluidtight manner, buoyant elements at the periphery of said floating cover being anchored to the upper part of the inclined wall of said pit, buoyant elements adjacent said central portion being operatively connected to said central portion by flexible fluidtight sheets, said interconnected buoyant elements and said interconnecting flexible sheets being arranged so that when said storage pit is empty said interconnected buoyant elements rest on said inclined wall, said cover then being in an expanded condition with adjacent interconnected buoyant elements spaced apart a distance at least sufficient to allow said adjacent interconnected buoyant elements to move together in an amount such that when said storage pit is substantially full of a liquid said interconnected buoyant elements float on the surface of said liquid without overlapping adjacent buoyant elements.