Patent ID: 7988409
Filing Date: 2011-08-02
Classification: E21B,F03B,Y10S

Abstract:
1. A turbine useful for power generation downhole over a flow range, comprising: a rotor impelled by a fluid flow; a stator, hydraulically communicating with the rotor, having a fluid flow path sufficient to impart tangential and axial vector flow components on a fluid flowing past the stator a shaft coupled to the rotor; and, one or more braking vanes connected to the rotor for rotation with the rotor, the one or more braking vanes imparting an increasing drag force on the rotor as the rotor and braking vanes rotate to reduce the rate of increase in speed such that rotations per minute is lowered compared to not having one or more braking vanes and, in turn, to relatively increase the flow range at higher flow rates; wherein said turbine is used for power generation downhole, and the increasing drag force increases with the higher flow rates.