| 摘要 |
<p>A blowout preventer comprises a housing with a pair of opposed rams carrying sealing blocks for sealing against tubing extending through the housing. Openings in the front side of the housing provide access to the sealing blocks for changing the blocks and a door closes the openings during normal in-service use of the preventer. A door guide permits the door to be slid in either of two opposing edgewise directions for exposing the openings one at a time but keeps the door from being movable substantially in a broadwise direction. Sealing inserts disposed within the openings between the door and the sealing blocks serve to seal against leakage and a rack and pinion mechanism provides the means for sliding the door from a centered position closing both openings to opposite edgewise positions exposing one or the other of the openings.</p> |
