GB567243A - Improvements in or relating to floating roofs for liquid storage tanks - Google Patents

Abstract

567,243. Tanks. WIGGINS, J. H. May 5, 1943, No. 7125. [Class 69 (i)] A liquid storage tank is provided with a floating roof comprising a central pontoon D spaced from a peripheral pontoon C and connected thereto by a preferably limber deck B which slopes downwardly and inwardly from the peripheral pontoon and has an annular trough E adjacent the central pontoon, the bottom of said trough being below the surface of the liquid when the roof is floating. When the tank is empty, the roof is supported on supports 7, 7a or on legs depending from the roof, the supports or legs being so arranged that the curvature of the trough is increased. A pipe or pipes 1a drain water from the trough, while excess water passes through outlets 2 into the tank. Where a single pipe 1a is provided, the centre pontoon D may be eccentric to the roof, the displacement being away from the pipe 1a so as to increase the depression at this part; weights may be placed adjacent the pipe to increase the effect. The centre pontoon D may be attached above or below the deck, and preferably has conical upper and lower ends. The peripheral pontoon is provided with manholes and an inwardly and downwardly sloping lower surface, and has an outer seal of substantial weight ; it is provided with radial bulkheads, and after construction is subjected to pressure, by gas or jacks, so as to camber the top and bottom walls, struts 10 being then connected to reinforcements 11 to hold the pontoon in expanded form. In another form, the deck slopes -steadily down to the centre pontoon, is connected thereto above the liquid level and is aligned with the lower surface of the central pontoon.