Abb Offshore Systems Limited

Christopher Richard King

James Brian Wilson

A flow control device comprises an outer sleeve having an outer sleeve wall and at least one aperture through the outer sleeve wall; a inner sleeve having an inner sleeve wall and at least one aperture through the inner sleeve wall; and means for providing relative sliding movement of the sleeves between &ldquo;open&rdquo; positions allowing variable flow of fluid through the apertures of the sleeves and a &ldquo;closed&rdquo; position, so that relative movement of the sleeves produces available amount of opening through which fluid can flows. The apertures are arranged so that the change in the coefficient of velocity (CV) of fluid flowing through the apertures caused by a change in the relative displacement of the sleeves is substantially proportional to said change in relative displacement.

Flow control device

Actuators for subsea downhole chokes have tended to include hydraulic pistons which are prone to failure and crude in accuracy. The invention provides an actuator ( ) having first and second rotary motors ( ) and an output region ( ) arranged to engage a load, such as a choke sleeve. In a first mode of operation, the first rotary motor ( ) imparts linear motion to the output in a first screw connection ( ). In a second mode of operation, the second rotary motor ( ) imparts linear motion to the output via a second screw connection ( ). The provision of screw connections permits gradual linear motion of the output to be achieved. The provision of two motors permits continuing performance in the event of failure of one of the motors.

Actuator

A flow control device comprises an outer sleeve having at least one aperture through its wall, and an inner sleeve having at least one aperture through its wall. Relative sliding movement of the sleeves is provided between &ldquo;open&rdquo; positions allowing for variable flow of fluid through the apertures of the sleeves and &ldquo;closed&rdquo; positions. A pressure-reducing region is arranged to reduce the pressure of fluid flowing through at least one aperture of one of the sleeves.

Growing community of inventors

Stroud, United Kingdom

Christopher Richard King