Patents Represented by Attorney, Agent or Law Firm Christensen O'Connor Johnnson Kindness PLLC
  • Patent number: 6732819
    Abstract: A mudsaver valve with retrievable inner sleeve. An annular piston is secured to a first end of the inner sleeve such that movement of the annular piston results in movement of the inner sleeve between a valve closed position and a valve open position. In the valve closed position radial outlet passages of the inner sleeve are blocked by a flow control sleeve. In the valve open position the inner sleeve is moved relative to the flow control sleeve so that the radial outlet passages are no longer blocked. The inner sleeve is maintained in the valve closed position until pump pressure acting upon the annular piston overcomes a biasing force of a biasing spring causing the inner sleeve to be carried by the annular piston to the valve open position.
    Type: Grant
    Filed: December 2, 2002
    Date of Patent: May 11, 2004
    Inventor: William Ray Wenzel