A one-way check valve assembly for use in the filler pipe of a vehicle fuel system to prevent liquid fuel from backing up the filler pipe. The check valve assembly includes a valve member formed from a resilient material, normally biased to a closed position in sealing engagement with the interior surface of the filler pipe flow passage, and forced open during refueling by the flow of fuel through the filler pipe inlet to the fuel tank. In a preferred form the valve member comprises a thin-walled flexible membrane formed in butterfly fashion about a central pivot member in the filler pipe. In an illustrative form the individual wings or sides of the valve member are semi-elliptical and in the closed position are angled downstream from the pivot point, conforming to the filler pipe contour in sealing fashion as angular sections of the flow passage. In a further embodiment the check valve assembly can be formed as a unitary, cup-like assembly axially inserted in sealing fashion on the filler pipe to locally define the flow passage around the valve member.
展开▼
