Shut-off valve apparatus

摘要

A shut-off valve apparatus has a valve body and a valve member coupled to the valve body. The valve member is movable between a first position blocking material flow through the valve body and a second position permitting material flow through the valve body. A pneumatic actuator receives pressurized air to move the valve member from the first position to the second position. A pneumatic exhaust controller controls the flow of pressurized air into and out of the pneumatic actuator.