Shutoff valve apparatus and mass flow control device with built-in valve

Abstract

Shutoff valve apparatus comprising: a valve block having a valve chest on which gas collects temporarily, an inlet flow path which makes gas flow into a valve chest, an outlet flow path into which gas is made to flow out of a valve chest, a valve seat located in the inlet port of an inlet flow path, or the outlet port, a diaphragm valve element located in the opposed position of the valve seat and closes the valve port by contacting with the valve seat, pressing means for pressing diaphragm valve element, an actuator plate disposed at the opposite side of the valve chest so that the diaphragm valve element may be opposed, an operation chamber divided with the actuator plate, and an operation gas supply exhaust mechanism in which operation gas is made to supply or exhaust into the operation chamber.