| 摘要 |
<p>A wellhead sealing system comprises a casing, a tubing spool and a bushing between the casing and tubing spool. A first recess is provided in the bushing and a first casing seal is mounted therein to act between the bushing and the casing. A second recess is provided in the tubing spool and a first bushing seal is mounted therein to act between the tubing spool and the bushing, The casing seal has cylindrical inside and outside surfaces located generally at the inside and outside diameters of the seal. The cylindrical inside surface is defined by a radially inwardly extending convex central protuberance and opposed cylindrical flat surface areas extending axially outwardly from the convex central protuberance into first transition areas extending to respective end surfaces. The outside surface is defined by a circumferential centrally located groove flanked by axially outwardly extending flexible retaining flanges forming second transition areas between the cylindrical outside surface and the end surfaces. Spring means extend around the inside circumference of the seal and are located adjacent each of the first transition areas.</p> |
