Fuel Limit Valves (FLVs) are used to establish ullage (airspace) in the tank and help prevent overfilling. They direct excess vapors generated during fueling back into the fuel fill hose.
Perko FLVs connect to 5/8" hose. They are designed to connect to vented fuel fills, where the excess vapors generated during refueling are cycled back into the fuel fill. FLVs do not connect to the carbon canisters those deal with vapors generated by expansion, not refueling.
Fuel Fill Limit Valves mount in the top surface of the fuel tank. Mounting options for tank mounted FLVs include flanged (for plastic tanks), threaded or welded (for metal tanks), and swivel (for both plastic and metal tanks). Flanged valves match the SAE 5-bolt level sender flange; (gasket is not included) Threaded valves mount with a 1" NPTF thread Swivel valves include valve, valve housing, O-ring, snap ring, and tank insert Distant sensing (DFLV) versions are available for both plastic and metal tanks on a custom basis Custom ullage set points are available.
Heavy on the technical side... Flow > 70 l/min @ 0.25 kPa Flow without corking @ 130 l/min Minimum reopening pressure: 0.5 kPa