Patent ID: 7156119

Claim:
A hydrant knock-off flow stop valve comprising: a generally cylindrical, vertically oriented, bulbous wall defining a central, vertical axis; an upper flange having circumferential recess so located as to receive a break ring for breakaway attachment of the lower flange of a wet hydrant; a lower flange for connection with a fluid system supply riser; a plurality of vertically disposed, circumferentially spaced vanes extending radially inward from said bulbous wall, said vanes having inner edges defining vertically oriented guides, said guides defining a generally cylindrical valve member guide; said bulbous wall forming a circumferential upper valve seat spaced below said upper flange along the interior wall thereof; a valve element free for vertical movement within said generally cylindrical valve member guide and so configured as to seal against said upper valve seat, closing upward flow of fluid through said valve; and a valve element restraining cage located in the upper portion of said valve, said cage having a centrally located valve member seat, a circumferential cage retaining ring spaced upward from said valve member seat, and a plurality of radially spaced cage legs extending between said valve member seat and said cage retaining ring; said upper flange defining an inner upward-opening cage retaining ring groove; said valve element restraining cage having said circumferential cage retaining ring removably located within said upward-opening cage retaining ring groove, said valve member seat being spaced below said upper circumferential seat by said plurality of spaced cage legs; whereby, system water flows through the riser, upward between said vanes, through said cage legs, and through said upper flange for supply of water to the wet hydrant; and whereby, upon the hydrant being accidentally impacted such that the break ring shears, water pressure acts upon said valve element, driving said cage upward, away from said valve and allowing said valve element to travel upward to said upper circumferential seat, forming a seal therewith and stopping water flow through said valve.