VACUUM GATE VALVE

摘要

The present invention relates to a vacuum gate valve which is mounted between a chamber and a vacuum pump and has a means for preventing a gas in the chamber from being brought into contact with an actuator of the vacuum gate valve when the gas is exhausted. A vacuum gate valve according to the present invention includes a valve casing formed with an inlet and an outlet, a valve plate installed to be moved forward/backward so as to open/close a flow of the fluid, and an actuator for moving the valve plate forward/backward. A hollow cylinder has one end hermetically fixed on the side of the outlet of the valve casing. A flange formed with a though-hole is hermitically fixed to the other end of the hollow cylinder. A bellows tube with an outer diameter smaller than an inner diameter of the hollow cylinder is inserted into and installed in the hollow cylinder while one end thereof is coupled to the flange. A piston cylinder has an outer diameter smaller than the inner diameter of the hollow cylinder and is inserted into and installed in the hollow cylinder while one end thereof is coupled to the other end of the bellows tube. The piston cylinder has the other end as a free end of which an outer peripheral surface is hermetically and slidably engaged with an inner peripheral surface of the hollow cylinder. The piston cylinder is provided with an annular pressure-receiving portion configured to extend from an outer peripheral surface of the piston cylinder and to be brought into close contact with the inner peripheral surface of the hollow cylinder.