Patent ID: 6854953
Filing Date: 2005-02-15
Classification: E21B

Abstract:
1. A speed governor suitable for use with a fluid driven downhole tool wherein said speed governor comprises an actuator operatively coupled to a motive fluid flow control valve, said actuator being formed and arranged so as to be activatable, directly or indirectly, in response to the running speed of the tool in use of said speed governor, said fluid flow control valve comprising a flow restriction valve formed and arranged for restricting motive fluid flow to said fluid driven downhole tool so that fluid flow through any downhole tool downstream of the fluid driven downhole tool is also restricted, wherein said actuator is provided with a resilient biasing device formed and arranged for, directly or indirectly, biasing said flow restriction valve away from a position for restricting motive fluid flow to said fluid drive, and wherein said actuator has at least one first displacement member, formed and arranged so as to be displaceable radially outwardly under the influence of centrifugal forces, directly or indirectly against the return force of said resilient biasing device.