Patent ID: 8181719

Claim:
A downhole flow pulsing device in combination with a drill string comprising a tubing string, a drilling motor having a stator housing connected in series with the tubing string and a rotor supported in the stator housing so as to be arranged to rotate relative to the stator housing and tubing string responsive to a flow of pressurized drilling fluid into the tubing string, a drill bit coupled to a bottom end of the rotor of the drilling motor so as to be arranged to rotate with the rotor of the drilling motor, and a rotor keeper, the downhole flow pulsing device comprising: a tubular housing arranged to be connected in series with the tubing string, the housing having an axial bore extending along a longitudinal axis therethrough so as to be arranged to permit passage of the drilling fluid therethrough; a valve supported in the bore of the tubular housing and defining a flow passage arranged to receive the drilling fluid therethrough, the valve comprising a fixed portion in fixed relation to the tubular housing and a rotating portion rotatably supported in the tubular housing so as to vary an area of the flow passage as the rotating portion rotates relative to the fixed portion; a drive link member arranged to be connected between the rotating portion of the valve and the rotor of the drilling motor so as to rotate the rotating portion of the valve relative to the tubing string together with the rotor of the drilling motor; wherein the rotor keeper comprises an annular retainer member mounted in series with the tubing string between the stator housing of the drilling motor and the tubular housing of the flow pulsing device and a keeper member extending through the retainer member so as to be connected in series between the rotor of the drilling motor and the drive link member, the keeper member including a portion of enlarged dimension above the retainer member which cannot pass through the annular retainer member.