Patent ID: 8061448
Filing Date: 2011-11-22
Classification: F03B,F05B,F16D,Y02E

Abstract:
1. A drilling apparatus comprising: a turbine provided with a turbine shaft, a hydraulic braking device configured to operate with the turbine, wherein the hydraulic braking device consists of a braking shaft coupled to the turbine shaft and bodies rotatably connected to the braking shaft, and wherein when the hydraulic braking device is immersed in a drilling fluid, an axial rotation of the turbine shaft causes an axial rotation of the braking shaft which in turn causes a movement of the bodies with respect to the drilling fluid, this movement generating a resisting torque that is a function of the square of the rotation speed of the turbine shaft with respect to the drilling fluid providing a quadratic relation, and wherein the construction of the hydraulic braking device is such that a braking effect is obtained when the rotation speed of the turbine shaft exceeds a predetermined threshold value and the braking effect is not obtained when under the predetermined value as a result of the quadratic relation.