Patent ID: 6202762
Filing Date: 2001-03-20
Classification: E21B

Abstract:
In a drilling assembly of the type comprising a fluid driven motor, a driveshaft operatively connected with the motor, a housing for enclosing the driveshaft and an annular flow passage defined between the driveshaft and the housing for circulating drive fluid therethrough, the improvement comprising a drive fluid flow restrictor device, the device comprising:(a) a constricted section in the annular flow passage;(b) an expanded section in the annular flow passage; and(c) a valve member positioned in the annular flow passage, the valve member being movable axially in the annular flow passage between the constricted section and the expanded section to define a flow restricting position and a normal flow position;such that when the valve member is in the flow restricting position the circulation of drive fluid through the annular flow passage is restricted and such that when the valve member is in the normal flow position the circulation of drive fluid through the annular flow passage is relatively unrestricted.