Anti-backflow insert for a fire hydrant outlet

摘要: An cylindrical hollow anti-backflow insert that can rapidly retrofit a fire hydrant to prevent forced liquid inflow into the after simple insertion of outflow nozzles hydrant. A curved flap having hinge at one end and an fin opposite is positioned within insert. Outflow water from will cause rotate upwards, which point protrudes interior sufficiently catch any stream force downward towards seal. The seal reversibly engages perimeter flap, thereby closing rear preventing