GB898297A - Improvements in liquid storage tanks - Google Patents

Abstract

898,297. Storage tanks. CHICAGO BRIDGE & IRON CO. March 28, 1961 [May 12, 1960], No. 11231/61. Class 69 (1). A polygonal-sided storage tank with a flat bottom 12 and a flat roof 18 supported on columns 13 has side walls 15 with curvature increasing from top to bottom so that their curvature R at any point P (Fig. 6) is given by where H=height in inches of top-capacity line, D, above the bottom of the wall. T=Tension in a vertical plane in a 1 inch wide strip of the wall plate. w=Density of the stored liquid in pounds per cubic inch. h is the distance in inches of P below D and k and j are selective constants based on the height of the stored liquid and on its weight respectively. The tank described is square with radiused corners. The columns 13 support beams 16 which are crossed by purlins 17 under the roof plates 18. In the type of tank concerned, horizontal stresses varying with height due to the liquid content are balanced by hoop-tensions varying due to the curve of the wall which is of steel plate of constant thickness. The boundary tensions at top and bottom are taken by the roof 18 and bottom 12 which are of steel plates lap-welded together. Unbalanced stresses due to the downward pull of the overhang B of the wall and the upward pressure on its upper port c are taken by trusses 14. In this Specification a sample relationship R P1 =T/wH (see Fig. 6) known to prior art is modified as at (1) above whereby the stresses in the roof and floor plates and in the truss members may be varied for effective and economical design. Values where j=H/H-kH and k=0.05 to 0.25 are claimed. Stress on the bottom plate may be reduced by connecting bottom plates 21 to side plates 22 to form a girder and by providing webs 23. U.S.A. Specification 2,593,408 is referred to.