Abstract: A rotating blowout preventor apparatus includes an adaptor located at the upper end of a main body, and a rotating head assembly which is removably received by the adaptor. The adaptor is longitudinally split to provide two segmented circles which are hinged together, and which may be opened to thereby enable a very large bit to be received within the main body. The rotating head assembly is left affixed to the drill string, with the bit located in underlying position respective to the rotating head assembly. Relatively small rotating blowout preventors can accommodate extremely large drill bits by utilizing the present invention.

Abstract: A heavy duty rotating blowout preventor which has a main outer support housing by which it can be affixed to the uppermost end of a casing, or to the uppermost end of a stack of tools affixed to the upper end of a casing. A rotating seal assembly includes a kelly drive bushing affixed to the uppermost end portion thereof, and a lower marginal end portion of the rotating seal assembly is removably received within the upper marginal end portion of the main support housing. The exposed upper marginal end portion of the rotating seal assembly forms an isolated bearing chamber by which the forces imposed by the kelly onto the rotating seal assembly is transferred into the main support housing in a new and novel manner. A stripper rubber assembly forms the lowermost end portion of the rotating seal assembly, and is separated from a nonrotating part of the rotating seal assembly by a stripper seal means which leads to a passageway underlying the bearing chamber.