Filler neck butterfly check valve

For use in a filler pipe of a vehicle fuel system having an inlet end for the introduction of fuel and an outlet end for delivering fuel to a fuel tank, a valve assembly for the filler pipe comprising:

• check valve means in the filler pipe comprising a resilient valve member biased to a closed position at a first downstream angle engaging an interior sidewall of the filler pipe, and moveable to an open position at a second further downstream angle, the valve assembly further including an angled seating surface on the filler pipe sidewall for engaging a peripheral portion of the valve member in the closed position, the seating surface being defined by an angular circumferential section of the sidewall corresponding to the peripheral portion of the valve member, wherein the thickness of the filler pipe sidewall is progressively thickened and the diameter of the filler pipe is correspondingly narrowed from the inlet end to the angled seating surface to form a venturi-shaped sidewall portion of the filler pipe, and the angled seating surface defines the throat of the venturi-shaped sidewall portion of the filler pipe.

Apparatus as defined in claim 5, wherein the filler pipe cross-section is circular and the valve member is elliptical.

Apparatus as defined in claim 5, wherein the valve member comprises a thin-walled flexible member formed in butterfly fashion about an anchor member extending transversely across the filler pipe, the valve member having two downwardly-angled wing portions engaging the sidewall of the filler pipe in the closed position.

For use in the filler pipe of a vehicle fuel system having an inlet for the introduction of fuel and an outlet end for delivering the fuel to a fuel tank, a valve assembly for the filler pipe comprising:

• an essentially cylindrical housing comprising an essentially circular fluid passage with an inlet end, an outlet end, a sidewall between the inlet and outlet end, a transverse rib member extending laterally across the fluid passage and integral with the sidewall of the housing, a downstream-angled seating surface comprising two semi-elliptical D-shaped surfaces formed in the sidewall of the housing and the transverse rib member, and a butterfly type valve member comprising a thin walled resilient member with a hinged middle supported on the angled seating surfaces in the transverse rib member and two wing portions supported on the angled seating surfaces formed in the housing sidewall, wherein the thickness of the sidewall progressively increases and the diameter of the fluid passage correspondingly decreases from the inlet end of the housing to the downstream angled seating surface, such that the downstream angled seating surface defines a venturi throat for assisting flow past the valve member from the inlet end to the outlet end.