Valve for drilling fluid telemetry systems

Abstract

A mud pulse telemetry system for imparting data pulses to drilling fluids circulating in a drill string including an improved valve arrangement for modulating the pressure of the circulating drilling fluid is disclosed. A shear-type valve is arranged in a through conduit configuration so that the seat face of the valve is covered when the valve is in an open position, thus preventing impingement of abrasive fluid particles on the valve seat face during the open flow position of the valve. The activation means is connected to the valve gate through a floating connection which prevents lateral stress forces operating on the valve from being imparted to the solenoid. The floating connection also permits convenient removal of the valve seat and gate from an access opening on the exterior of the drill string housing to facilitate the replacement of critical valve parts without removing the valve subassembly from the drill string. The valve gate and seat have an oblong valve flow opening therein which provides for sufficient fluid flow to adequately modulate the fluid pressure and at the same time provide a minimum length of stroke for the solenoid to operate the valve. An upset rim on the valve seat provides a seating face smaller than the opposing seating face of the gate.