Couplers & Adaptors

Cla-Val aviation refueling couplers and adapters are used for the mechanical interface of fuel lines, hydrant pit valves, underwing nozzles, refueling vehicles, and fixed pipework systems. Selection depends on the required duty: a fixed single-point adapter for fuel receipt or delivery, or an active hydrant coupler with pressure control, deadman actuation, and surge pressure protection.

The 340GF Pressure Fuel Servicing Adapter is a single-point adapter for pressurized fuel servicing. It conforms to MS24484-5 and MIL-A-25896 and uses a 2.5 in single-point bayonet connection. The unit is intended for refined petroleum products. Available inlet connections include threaded and flanged configurations. Principal materials are investment-cast 17-4PH stainless steel for the body, A356T6 aluminum for the poppet and spider, stainless steel spring elements, and a fluorosilicone poppet seal. The stated temperature range is -55°C to +93°C for fuel service and -55°C to +177°C for ambient exposure.

The 353GF Pressure Control Coupler is used in hydrant refueling service for connection to a hydrant pit valve or hydrant pit adapter, allowing fuel transfer from the underground hydrant main to the aircraft. It incorporates a direct-acting pressure regulator with deadman control to limit overpressure and transient surge conditions. The datasheet states qualification to EI 1584 3rd Edition and compliance with EI 1584 4th Edition. The coupler connects to standard EI 1584 hydrant valves and is available with pneumatic or hydraulic deadman operation. Additional features include a fuel-sense connection, pilot block bleed valves, opening time of 5-10 s, and adjustable closing time.

During maintenance, inspection should cover sealing faces, bayonet lugs, poppet travel, fluorosilicone seals, bleed valves, fuel-sense and deadman hoses, and cleanliness with respect to particulate contamination or trapped air. Incorrect adapter or coupler selection can affect pressure drop, isolation capability, purge procedure, and safe disconnection under operating conditions.