| 摘要 |
<p>A wall mounted water hydrant has an elongated hollow housing with water inlet and outlet ends, and a center axis; an inlet valve in the housing adjacent to the inlet end, including a valve seat and a valve body; a water outlet port in the housing adjacent to its outlet end; a valve operating rod in the housing with its an inner end secured to the valve body and extending along the center axis to the outlet end of said housing, terminating in an outer end; a handle attached to the rod outer end, which when rotated in one direction closes the valve body against the valve seat, and in the other opposite direction moves the valve body away from the seat, thus allowing pressurized water from the inlet to flow downstream through the housing and outlet port; and a backflow preventor secured to the valve downstream from its seat. The elastomeric backflow preventor has a bell shape comprising a cylindrical body smaller than the interior of the housing and thin flexible side walls extending from the body outwardly and downstream to end in a lip portion which normally engages the interior walls of the housing. The construction of the preventor permits it to deflect toward the axis of the housing when water is flowing in a downstream direction and to engage the interior surface of the housing if backpressure urges water to flow in an upstream direction, thus sealing the valve means against backflow.</p> |
