Limited Condition of Conical Shell Designed on the Basis of Middle Diameter Formula

According to rules of GB150 Steel Pressure Vessel, thickness of cylindrical shell, spherical shell and conical shell can be calculated by middle diameter formula, and provide limited application condition of these formulas for cylindrical and spherical shell. However, comparing conical shell does not exactly so. Though contrasting and analyzing of calculate formula for thickness and film stress of cylindrical and conical shell, the limited condition is deduced to calculate thickness of conical shell on the basis of middle diameter formula.