BELLOWS PROTECTIVE STRUCTURE OF A GATE VALVE, CAPABLE OF PREVENTING DAMAGE TO A BELLOWS OR A DECREASE IN THE LIFE TIME THEREOF CAUSED BY APPLYING PRESSURE

摘要

PURPOSE: A bellows protective structure of a gate valve is provided to prevent damage to a bellows by sensing and reducing air pressure even though the air pressure over a predetermined level is applied to the inside of the bellows.;CONSTITUTION: A bellows protective structure of a gate valve surrounds a load unit(323) advancing and retreating according to free driving pressure and lock driving pressure. A seal unit part is operated by an increase in the air pressure so that the gate valve opens/closes an opening of a valve casing(100). The seal unit part is composed of an opening/closing cylinder, a back plate(310), and a seal plate(330). The opening/closing cylinder includes the load unit. The back plate receives the free driving pressure and the lock driving pressure and discharges air through a free driving pressure outlet and a lock driving pressure outlet, thereby transmitting the air to the cylinder. The load unit of the opening/closing cylinder is attached to the seal plate. The opening/closing cylinder includes a safety valve sensing the air inside of a bellows(326).;COPYRIGHT KIPO 2013