| 摘要 |
A blow out preventor assembly for attachment to the drill stem and being placed within the drill casing during well operations provides a bottom seal assembly having an attachment for slideably attaching the bottom seal assembly peripherally to a section of drill stem with the bottom seal assembly having at least one flow opening allowing oil, gas and drilling fluids to pass therearound. The upper portion of the bottom seal assembly forms a valve which cooperates with a provided port-ring mounted above the bottom seal assembly and having an outer diameter substantially equal to the diameter of the casing. The port-ring forms a flow closure between the drill stem and casing, and has at least one flow opening therethrough and a valve seat at the valve opening adapted to receive the valve portion of the bottom seal assembly. Upper and lower seat rings provide gravitational supports to the port-ring and bottom seal assemblies respectively. A sudden pressure surge will act upwardly on the underside of the bottom seal assembly forcing it upwardly and into direct contact with the top port-ring with the valve portion of the bottom seal assembly contacting the valve seat provided on the port-ring to form a closure. The combined assemblies forced together during the surge move upwardly on the drill pipe as a result of the down hole pressure until the port-ring assembly makes a contact with and seats itself at the bevelled surface portion of a conventional drill stem assembly. Upward movement of the combined assemblies will thus cease and the down hole pressure is contained.
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