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Air Shutoff Valves

The Fluid Power Energy (FPE) C, CF, and CF/CFM series are a range of easily installed diesel engine air intake valves that automatically close on engine overspeed. The are designed for situations where flammable gas or vapor may enter the atmosphere in an area in which a diesel engine is operating.

Use of Air Shutoff Valves

The Fluid Power Energy (FPE) C, CF, and CF/CFM series are a range of combined manual and automatic overspeed shut down valves designed for situations where flammable gas or vapor may enter the atmosphere in an area in which a diesel engine is operating.

Should such flammable material be drawn into the engine intake, this may result in uncontrolled engine overspeed, and a situation in which shut down of the diesel fuel supply may fail to stop the engine.

Under these circumstances, a rapid shut down of the engine is required by immediate closure of the engine air intake thereby reducing the potential for significant damage and possible ignition of the flammable material in the surrounding atmosphere.

The valves are suitable for installation in the intakes of either naturally aspirated or turbocharged engines.

Once installed and set, the repeatability of the actual engine automatic shut down speed has a greater scatter in the case of turbocharged engines than for naturally aspirated types. However, unless there is an individual requirement for an exact shut down speed, adequate protection from excessive engine overspeed is achieved.

How Air Shutoff Valves Work

The actuation force to close an air shutoff valve is derived from the engine intake air flow passing through the valve. As the air flow increases, this actuation force also increases. The actuation force is resisted by an internal valve spring, the pre-load of which is adjusted via the “Trip Adjuster Screw.”

Once the actuation force exceeds the resisting force of the valve spring, the valve rapidly moves to the closed position. Once closed, the valve remains shut until the engine has entirely stopped. The valve then resets to the open position after a slight delay.

The FPE CM Series of air shutoff valve include a cable-operated manual shut down.