HOLDING METHOD OF CYLINDER

PURPOSE:To make construction simple and initial cost low by mounting a restraining cylinder to the outside of a cylinder or split cylinders to be internally exerted with pressure and pressurizing the space therebetween by a pressure medium thereby offsetting and relieving the internal stress exerted on the cylinder or split cylinders. CONSTITUTION:A restraining cylinder 16 is mounted to the outside of a cylinder or split cylinders 2 to be exerted internally with a pressure P1 and the space made by sealing hermetically the fitted part with an O-ring 17 is pressurized P2 by a pressure medium such as oil or the like. The internal pressure P1 acting on the cylinder 2 is offset and relieved by the external pressure P2 by which the pressure resistance of the cylindrical body 2 is made stronger or the wall thickness thereof is made thinner. The construction is thus simplified and the initial cost is reduced.