Control

Cla-Val control valves for rail and aviation fuel handling are used in light petroleum service where combined downstream pressure control, surge suppression, and deadman shut-off are required. Model 90AF-4A-3 is a hydraulically operated, diaphragm-actuated valve in globe or angle pattern. Typical applications include bottom-loading pantograph systems, rate-of-flow control, pressure reducing service, and check-valve duty.

Valve selection is based on static and dynamic line pressure, required downstream set pressure, deadman actuation method, process fluid, and allowable pressure drop. The construction consists of body, cover, and diaphragm assembly, with the diaphragm serving as the primary moving element. In the event of diaphragm failure, the valve moves to the closed position, which is a relevant fail-safe characteristic in fuel loading and refueling systems.

Flanged configurations are available in sizes 1 1/2 in. to 16 in. for globe pattern and 2 in. to 16 in. for angle pattern. End connections and body materials include cast aluminum to ANSI B16.1, cast bronze to ANSI B16.24, ductile iron to ANSI B16.42, and cast steel to ANSI B16.5. Available pressure classes include 150, 250, and 300, with maximum working pressure up to 400 psi depending on material and class. For light petroleum products, the stated operating temperature range is -40°F to +140°F.

Maintenance assessment typically includes the diaphragm, resilient disc, renewable seat, pilot circuit, flow-clean strainer, isolation cock, and opening/closing flow control settings. The packless design, with no stuffing box, reduces external leakage paths. Internal components can be serviced without removing the valve from the pipeline, which limits disassembly work in installed fuel transfer systems.