The Shut Off Valve Function with Rubber Tube Inserts
Shut off valves function most commonly by air, there are also two versions of an air operated valve. Firstly we have the normally open shut off valve function which, when no air pressure is applied the valve will fail open. There is a rubber tube inside the valve body, this rubber tube, also known as a sleeve, bladder, hose or membrane pinches/squeezes together once air pressure is applied shutting off the valve.