| 摘要 |
<p>A bailer that is substantially leak-free includes an improved valve assembly at its lowermost end. In a first embodiment, a valve body in the form of a hemispherical ball is mounted at the lowermost end of a straight valve stem. The hemispherical ball seats in a valve seat that matches the contour of the hemispherical exterior surface of the ball. In a second embodiment, the valve body and the matching valve seat are both frusto-conical in configuration. In a third embodiment, the valve body and matching valve seat are tapered downwardly to form an elongate, narrow slot. A fourth embodiment adds a guide member to the third embodiment structure to ensure seating of the downwardly tapering valve body in its valve seat. In all embodiments, the valve stem is slideably received within and guided by a central bore formed in a support member that spans the hollow interior of the lowermost end of the bailer, and the valve body is covered with a cushioned material of uniform thickness. The cushioned material is deformed by particulate matter but seals around such matter so that leak-free seating of the valve body against the valve seat is achieved even when particulate matter is disposed between the valve body and the valve seat. Moreover, the flexibility and resilience of the cushioned material enables it to seal valve bodies and valve seats that are out-of round or otherwise outside of manufacturing tolerances.</p> |
