Patent attributes
A system for on-line testing of an emergency shut-off valve includes a first emergency shut-off valve (first valve) and a flow control valve (second valve), with the system being configured to allow the second valve to serve as a combination flow control and second emergency shut-off valve. A subsystem is also provided for testing the first valve without fully closing the first valve in response to a signal from the control. In this subsystem, a solenoid valve bleeds off pressurized fluid to move the first valve from a fully opened to a partially closed position. A bypass around the second valve allows it to be tested as the second emergency shut-off valve, allowing the second valve to close completely without shutting down the process. The use of the two emergency shut-off valves in series wherein either valve can shut down the process provides a level 3 safety integrity level.
