Rotary Plug Well Safety Valve

1,187,698. Valves. HYDRIL CO. 11 Sept., 1968, No. 43178/68. Heading F2V. A valve 10, adapted for controlling flow through a well pipe 11, includes a rotary plug 19 which has a bore 20 extending therethrough, is disposed within an enlarged portion 16 of the pipe bore 15, and is journalled between a pair of opposed bearing plates (22, 23, Figs. 3 and 4, not shown), the plates being retained between pipe portions 12 and 13, receiving plug bearing shafts, (35, 36), and having bearing balls (26) disposed between them and the plug, the balls being contained within ball races (27, 29) formed partly in the plates and partly in the plug. Plug bearing shaft (36) extends through the pipe portion interconnector 14 and has attached to its free end a crank 38. An annular sleeve 50 is slidably mounted circumadjacent interconnector 14 and has formed therein a longitudinal slot 51 within which a main portion 38a of the crank is disposed, and a further transverse slot which provides cam surfaces 54, 55 and accommodates the crank small end 38b. Upon application of pressure, via line 60a. to a chamber 59 formed at one end of the sleeve 50, the latter moves downwardly and, through the crank 38, rotates the plug 19 to a position wherein its bore 20 is in alignment with bore 15. Closure of the valve may be achieved either solely by the removal of applied pressure in which case springs 67, acting on the other end of the sleeve, move the sleeve upwardly, or by the application of a second pressure, via line 66, to the said other end of the sleeve, i.e., to chamber 64. In two modifications (Figs. 6 and 7, not shown) the second pressure line 66 and its connector 66a are replaced by a piston contained within a cylinder and enclosing a compressible fluid, or by a bellows which is subject to ambient pressure, respectively. In a further modification, (Fig. 5, not shown), the valve includes two serially arranged plugs 19 actuated in a manner similar to that above, the actuation being substantially in synchronism.