Pressure Reducing Valves
Cla-Val pressure reducing valves for aviation fueling are applied in fuel lines where higher upstream pressure must be reduced to a controlled downstream pressure despite variations in flow rate or inlet pressure. This category includes the 93-99 Pressure Reducing Valve, which the manufacturer classifies under Fueling Pressure Reducing Valves and describes as a pressure reducing valve with solenoid shutoff.
The 93-99/693-99 is a pilot-operated combination pressure reducing and solenoid shutoff valve. The control arrangement includes a CRD pressure reducing control, CS3XM solenoid control, X47A ejector, and reverse-flow Hytrol main valve, with either de-energize-to-open or energize-to-open logic depending on the automation philosophy and fail-safe requirements of the system.
In fueling service, the valve is used where downstream pressure must be limited to protect equipment such as loading arms, fill stands, pantographs, or fuel distribution headers, while also providing remote shutoff by electrical signal. Valve selection should not be based on line size alone; it also requires evaluation of available differential pressure, required set pressure, transient response during closure, potential reverse-pressure conditions, and compatibility with aviation fuel service.
Available control options include an X46A flow-clean strainer or X43 Y-strainer for pilot circuit protection, CK2 isolation cocks for control system isolation, CV opening and closing speed controls, check feature, quick-connect test points for pressure gauges, X101 valve position indicator, and an optional X105L switch assembly for position indication.
Maintenance checks should include strainer cleanliness, correct isolation cock position, venting of air from the cover and pilot system, solenoid supply voltage, adjustment of flow controls, and seat and diaphragm leakage integrity. Periodic verification of downstream pressure is important, since pilot circuit drift or particulate contamination can affect control stability and valve response time.
