US 9,551,186 B2 · Turbine speed control system for downhole tool

Abstract

Systems, methods, and devices are provided to generate a stable supply of electrical power in a drill string. In one example, a downhole turbine generator includes a turbine, a speed governor, and an alternator. The turbine may transform hydraulic power of a first fluid medium into rotational power of a rotating shaft. The speed governor may reduce the rotational power of the rotating shaft in a variable amount that depends on the speed of the rotating shaft. Specifically, weighted arms may shear a second fluid medium more when the speed is higher and less when the speed is lower. The shearing of the second fluid medium may generate a countervailing torque on the rotating shaft to reduce the rotational power of the rotating shaft. The alternator then may produce a generally stable supply of electrical power from the rotational power of the rotating shaft.

Claims16

Dependent claims

A downhole turbine generator comprising:

a turbine to transform hydraulic power of a first fluid medium passing through the turbine into rotational power of a rotating shaft
a speed governor to reduce the rotational power of the rotating shaft by a variable amount depending on a speed of the rotating shaft, wherein the speed governor comprises weighted arms that shear a second fluid medium to a greater degree when the speed of the rotating shaft is higher and shear the second fluid medium to a lesser degree when the speed of the rotating shaft is lower, wherein the shearing of the second fluid medium generates a countervailing torque on the rotating shaft that reduces the rotational power of the rotating shaft;
and
an alternator configured to produce electrical power from the rotational power of the rotating shaft,
wherein at least a part of each weighted arm of the speed governor is configured to shear the second fluid medium by extending farther away from the rotating shaft and further into the second fluid medium when the speed of the rotating shaft is higher.

2 more elements

A rotational speed governor for a downhole turbine generator, the rotational speed governor comprising:

a housing containing a fluid medium;
a rotatable shaft at least partially disposed within the housing, wherein the rotatable shaft is configured to rotate along a first axis;
a first member attached to the rotatable shaft, wherein the first member extends radially from the rotatable shaft;
a first weighted arm coupled to the first member, wherein the first weighted arm is configured to be at least partially rotatable around a second axis, wherein the second axis is parallel to the first axis and the second axis is configured to revolve around the first axis when the rotatable shaft rotates;
wherein a rotation of the rotatable shaft is configured to cause a centripetal force that causes the first weighted arm to at least partially rotate around the second axis, thereby extending into, and shearing, a volume of the fluid medium, wherein the shearing of the fluid medium by the first weighted arm results in a countervailing torque on the rotatable shaft that reduces a rotational power of the rotatable shaft to a greater degree when the rotation of the rotatable shaft is higher and that reduces a rotational power of the rotatable shaft to a lesser degree when the rotation of the rotatable shaft is lower.

2 more elements

Dependencies are inferred from the claim text.

Turbine speed control system for downhole tool

Life of this patent

Turbine speed control system for downhole tool

Life of this patent

Abstract

Claims16