Floating roof for liquid storage tanks, particularly for the storage of liquid petroleum products

Claim 1

A large diameter floating roof for liquid storage tanks, particularly for the storage of liquid petroleum products, including a peripheral hollow annular pontoon member, a sheetlike member extending substantially over the entire roof area and fixed to said peripheral pontoon member, an annular load member arranged on said sheetlike member forming a depressed annular zone in an intermediate area concentric with the pontoon member and disposed radially inwardly thereof, said annular load member comprising a hollow annular member rigidly fixed on said sheetlike member adjacent said depressed annular zone and having continuous upstanding sidewalls to hydraulically separate said sheetlike member into two portions defining two distinct concentric draining sections, each of said draining sections having at least a draining hole in the range of said depressed annular zone, and further including a plurality of feet for supporting at least one of said portions of said sheetlike member defining said draining sections, said feet being arranged circumferentially spaced apart on two radially separated concentric circular lines and staggered with respect to each other, so as to confer a sinoidal form to said portion of said sheetlike element to allow draining of the roof even when the roof is supported on the bottom of said tank through said feet.