Abstract
The safety of ship valves requires confirmation only by pressure shell tests, but ship-mounted valves are subject not only to pressure but to various forces applied through pipes during ship construction and operation. We therefore investigated the safety of type 5K-80A valves by experiments and numerical analyses. The results may be summarized as follows: (1) The vertical force that can cause leakage from the valve seat is less that the corresponding horizontal force, but the critical value of vertical force is much smaller than the force exerted on an actual valve. (2) The pressure test showed a safety factor of 21.6, which is far greater than the factor of 8 required by the design standard. (3) Operating torque increases, rather than decreases, the safety of a marine globe valve.
