Scram valve
The scram valve has a closing piston which can be controlled by a pilot valve in a pressure medium supply line to the closing piston. The pilot valve has a control piston which is spring biased on one side and connected on the other side with the flow of medium in the outlet spigot of the scram valve. Thus, should the pressure in the outlet spigot drop, the control piston moves to open the pressure medium supply line to the closing piston. In addition, this supply line is connected at the upstream end to the scram valve casing upstream of the valve seat so that the pressure of the medium flowing through the scram valve aids in the closing of this valve.