Baker Hughes Corporation

Michael S Rawson

Clifford H Beall

Doug Trott

Kurt A Hickey

Mark S Megill

Charles M Tompkins

Ronald D Williams

A torsion spring return system for a valve closure member, preferably for downhole use in an SSV, is described. The closure member or flapper uses torsion springs which can be wrapped circumferentially within the body of the downhole tool, generally following the periphery of the flapper. Downward rotation of the flapper stresses the torsion springs so that subsequently, when a flow tube or other device holding the flapper in one position is released, the torsion springs return the flapper to its seat. The connection between the torsion springs and the pin supporting the flapper is either a universal joint or involves an alignment rod running through the torsion spring, as well as other mechanisms which facilitate stress relief in the connection between the torsion spring and pivot pin.

Torsion spring connections for downhole flapper

Internal and external metal-to-metal radially interfering seals are provided for an annular chamber. Typically, an annular chamber is used in tubular goods to be part of the hydraulic control circuitry, such as for operating subsurface equipment such as a subsurface safety valve. Resilient seals are eliminated and sealing reliability is enhanced by a design which features metal-to-metal seals internally and externally, preferably assembled by an external two-step thread. The radial interference seal, which is internally disposed, is constructed so as to be incapable of experiencing tensile loads. This reinforces joint integrity by minimizing stresses on thin components.

Annular chamber seal

An electro-hydraulic surface controlled subsurface safety valve is controllable entirely electrically. The actuator operates on an electrically actuated pressure pump and a supply of hydraulic fluid reservoired in the tool proximate to the safety valve. A dump valve is normally open so that if power fails, pressure is released and the safety valve closes.

Electro-hydraulic surface controlled subsurface safety valve actuator

An electric safety valve actuator for a surface controlled subsurface safety valve. The actuator includes a motor drive and driver selectively coupled with a drive yoke connected to an otherwise conventional flow tube of a downhole safety valve.

Electric safety valve actuator

A valve actuator preferably driven by an electric motor is disclosed. The valve actuator is useful with surface safety valves and uses power input from an electric motor to position the valve in its normal position. A mechanism is provided to allow the valve to shift positions to a failsafe position upon failure of electrical power to the motor connected to the actuator. A screw drive is provided with the motor, with a latch mechanism holding a nut against rotation. The nut can advance longitudinally upon rotation of the drive to move a valve stem. Upon failure of electrical power, the latch mechanism releases the nut from a coupling in the actuator which is connected to the valve stem, and the main return springs in the actuator allow the nut to rotate with respect to the screw drive so that the valve can assume its failed position. Normal applications allow the valve to fail closed; however, the valve can be configured so that failure results in opening of the valve if the application requires it.

Electrically driven actuator with failsafe feature

The invention relates to a pair of matched surfaces usable in sealing a downhole subsurface safety valve. The continuous seat and the matching flapper profile feature a surface that is around its periphery transverse to the longitudinal axis of the seat and the flapper. The seating surface, if extended in a two-dimensional plane, defines an undulating shape which can be a sinusoidal shape in the preferred embodiment. The result is an improvement in the performance of the metal-to-metal contact between the seat and the flapper, coupled with a self-centering effect when the seating surface on the flapper, which is formed adjacent a shoulder, is presented in opposition to the seat. Additionally, the transverse undulating seat can have an embedded groove which accommodates a resilient seal, preferably PTFE or Teflon.RTM..

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Tulsa, OK, United States of America

Michael S Rawson