Patent ID: 8453744

Claim:
An apparatus for downhole use in a fluid-filled well, the apparatus comprising: a longitudinal tool body; a plurality of extendable arms mounted on the tool body for opening and closing within the fluid-filled well; a flexible valve sleeve attached to the plurality of extendable arms and moveable between a stowed position and an unstowed position by movement of the extendable arms, wherein in the unstowed position the valve sleeve is arranged to receive a flow of fluid from the well and the pressure of the fluid in the valve sleeve causes at least a portion of the valve sleeve to seal against a wall of the well, and wherein in the unstowed position, the valve sleeve causes the flow of fluid to exit a downstream end of the valve sleeve such that the diameter of the flow of fluid upon exiting the valve sleeve is greater than a diameter of the longitudinal tool body; wherein the flexible valve sleeve has at least a first tapered section, a first end of the tapered section of the sleeve having a first diameter and a second end of the tapered section having a second diameter, the first diameter being greater than the second diameter and greater than an anticipated internal diameter of the well, and wherein the first tapered section is attached to the extendable arms, such that in use the portion of the valve sleeve that seals against the wall of the well is intermediate the first and second diameters.