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Fail safe surface controlled subsurface safety valve for use in a well

  • US 6,619,388 B2
  • Filed: 02/15/2001
  • Issued: 09/16/2003
  • Est. Priority Date: 02/15/2001
  • Status: Expired due to Term
First Claim
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1. A fail-safe, surface controlled subsurface safety valve for use in a well, comprising:

  • a valve body having a longitudinal bore for fluid to flow through, a bore closure assembly, a pressure balanced drive assembly, and a fail safe assembly;

    the bore closure assembly being positioned and normally biased to close the bore to fluid flow;

    the pressure balanced drive assembly coupled to the bore closure assembly for driving the bore closure assembly to an open position wherein the pressure balanced drive assembly further comprises a sealed chamber filled with an incompressible fluid and the pressure of the incompressible fluid is balanced with the wellbore pressure by at least one bellows connected to the sealed chamber; and

    the fail safe assembly being positioned and configured to hold the bore closure assembly in the open position in response to a hold signal and to release the valve to return to the safe, closed position upon interruption of the hold signal.

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