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Chalwyn System Selection Guide

How to Select

Our System Selection Guides provide an overview of the most common types of air intake shutoff systems used to prevent diesel engine overspeed or runaway. We have a wide range of fully automatic and manual shutoff systems and will help you find a system that meets your requirements.

Air Intake Shutoff Valves

Air Intake Shut Down Valves

Air intake shutdown valves (often referred to as AISV, ASOV or Emergency Shutdown valves, ESD) and systems provide emergency overspeed shutdown protection for diesel engines and are the most effective way of preventing a runaway situation. The valves completely block the engine air intake system, cutting off an uncontrolled external fuel source and the air required to keep the engine running.

Revguard Speed Switches

Speed Switches

Chalwyn Revguard Speed Switches detect the hazard of an overspeed condition. When engine RPMs exceed the Revguard’s program setpoint, the output is energized, providing the signal to actuate the air intake shutoff valve(s) to shut off your engine.

FSX-200 Fuel Shutoff Valve

Fuel Shutoff Valve

European standards (EN 1834-1:2000) covers diesel engine operation in Zone 1 or Zone 2 hazardous areas where flammable gas or vapor may exist, requires that both the engine fuel and intake air supply are automatically shut down if engine overspeed occurs.


Spark Arrestors


ASX-200-310-405 Group

Flameproof Alternators

Standard automotive type alternators are a continuous potential source of ignition when operated in hazardous atmospheres where combustible concentrations of gas, vapor or dusts may exist. Chalwyn offers a range of ATEX approved flameproof alternators designed specifically to mount onto diesel engines as direct replacements for the standard alternator.

Miniature Charging Valves

Compact high quality corrosion resistant charging valves based on Ministry of Defence Approved designs (Approval numbers available). originally designed for pneumatic or hydraulic systems, these valves can be used with a range of fluids and gases subject to the correct valve seat specification being selected.