Patent ID: 6978801

Claim:
A backflow prevention valve attached to a fuel supply pipe for preventing a backflow of fuel, comprising: a cylindrical case member having a peripheral wall, an inflow opening formed at one end, and an outlet formed in at least one of the other end and the peripheral wall, a plurality of ribs integrally formed with the case member and projecting inwardly from an inner surface of the peripheral wall to extend along an axial direction of the case member, a valve member formed of a cylindrical main member disposed in the case member to be movable in the axial direction thereof so that the ribs contact an outer peripheral surface of the valve member to support and guide the same, said valve member having a sealing portion at an upper surface thereof for contacting a peripheral edge of the inflow opening to close the same, an urging device disposed in the case member for urging the valve member toward the inflow opening, a liquid inflow pipe extending outwardly from the case member around the inflow opening and having a smooth inner surface to allow the fuel to smoothly flow through the backflow prevention valve, and a covering member attached to a bottom of the case member, said urging device being disposed on the covering member.