GB876436A - Improvements relating to floating covers for tanks - Google Patents

Abstract

876,436. Tank covers. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. Nov. 26, 1959 [Nov. 28, 1958], No. 40204/59. Class 69 (1). A floating cover for a tank filled with volatile liquid comprises a thin sheet 2, Figs. 1, 2, of thermoplastic material such as a polyester or polythene supported by tubular floats 3 which are interconnected in liquid-tight manner to the upper surface forming separate spaces 6 to confine any fluid leaking through the sheet 2. The tubes 3 may be arranged annularly and concentric as in Fig. 1 or may be straight as in Fig. 2, shorter sections 8, 9 &c. being used for connection to an outer annular tube 5. The tubes 3, 5 are glued or welded to the sheet 2 and may be additionally held by an overlapping glued or welded strip 21, Fig. 4, or by wrapping and enclosing with a split tube 23, Fig. 6. Alternatively the sheet 2, Fig. 5, may be wrapped over a solid cylindrical insert 22 located within a recessed tube 3. In another example the cover has a pair of tubes 5, 11, Fig. 7, at the rim over which the edge of the sheet 2 is wrapped and glued or welded at 12. A sponge rubber seal 17 is attached by aluminium clamps 13 engaged over the tubes 5, 11 and carrying bolts 14 for the seal 17 which is engaged between aluminium strips 15.