ABSTRACT
Single-curvature polyhedron bulging technology for manufacturing spherical vessels has been adopted to build many spherical vessels without using large dies and presses. It has been proved that fabrication cost can be reduced and period can be shortened, comparing with the conventional technology for manufacturing spherical vessels. When a spherical vessel is used as a pressure vessel, its ovality and angular distortion has to be less than or equal to some values specified in spherical tank standards. In this paper, two similar parameters with the ovality and angular distortion of a spherical vessel are introduced. Their applications in controlling the bulging process of a polyhedron are also given.
