| 摘要 |
<p>A downhole tool includes a lubrication system. The tool has a first cylindrical body member in which is disposed a longitudinally extending annular cavity, and that cavity is communicated with a space outside the tool, which space is filled with a first fluid. A cylindrical extension member has a first end received in the annular cavity in longitudinally sliding engagement and has a second end extending longitudinally from the annular cavity. Slidingly disposed in the annular cavity is an annular floating seal which sealingly engages radially inner and outer surfaces of the annular cavity and which separates a second fluid in the annular cavity between the floating seal and the cylindrical extension member from the previously mentioned first fluid. The second fluid is preferably a lubrication fluid and thus provides lubrication to the downhole tool which is sealed from contaminating communication with the previously mentioned first fluid.</p> |
