| 摘要 |
An improved wellhead valve includes a tubular body with a central passage therethrough and with a downwardly facing valve seat surrounding a portion of said passage, a cylindrical sealing surface above said valve seat, internal threads above said sealing surface and external threads, a valve member positioned within said passage below said valve seat and biased toward engagement with said valve seat, a plug having external threads for engagement with the internal threads of said body and having a sealing means for sealing against said cylindrical sealing surface and a projection extending downwardly from said sealing means, said plug when positioned within said central passage with its sealing means engaging said sealing surface closing flow through said body and said plug being movable downwardly so that its sealing means is below said sealing surface and its projection engages said valve member to move it out of engagement with the valve seat so that flow through said central passage is open and further rotation of said plug provides retrieval of the valve body from within the wellhead housing. |
