Patent ID: 6971406

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, an outlet formed in at least one of the other end and the peripheral wall, and a plurality of holes formed in an upper end at a periphery thereof, a valve member disposed in the case member to be movable in an axial direction thereof and having a sealing portion at an upper surface thereof for contacting a peripheral edge of the inflow opening to close the same, and a plurality of guiding arms provided on a peripheral edge of an upper surface of the valve member, said guiding arms being slidably disposed in the holes so that the valve member is supported and guided by the guiding arms passing through the holes, an urging device disposed in the case member for urging the valve member toward the inflow opening, and 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.