Patent ID: 6488092
Filing Date: 2002-12-03
Classification: E21B

Abstract:
A by-pass valve for controlling the path of a fluid stream moving down a bore in a drill string suspended in a well, the by-pass valve comprising:a) a housing arranged to function as a length element of drill string, with a generally central opening which conducts the fluid stream; b) a selector means in said opening to control a selective control valve in response to manipulation of fluid flow rate down the drill string bore; c) said selective control valve comprising a poppet manipulated by said selector means arranged to cooperate with an orifice which conducts said fluid stream; d) a piston, with an orifice, sealingly situated in said opening, arranged to carry said orifice and move in response to pressure differential created by said selective control valve; e) a main stream by-pass valve in said opening, responsive to movement of said piston to change between open and closed states; f) a channel to conduct said fluid stream from said main stream by-pass valve to a plenum, said plenum formed by an outer surface of said piston an a wall of said opening; g) a spring to urge said piston to move to close said main stream by-pass valve; and h) ports in fluid communication with said plenum to direct the fluid stream from said housing into the well.