Patent ID: 8272835

Claim:
A gas turbine engine comprising: a turbine blade; an adjustable casing; and a clearance control arrangement, the clearance control arrangement further comprising: an actuator operatively connected to a piston within a cylinder, wherein the piston divides the cylinder by a sealing engagement with a wall of the cylinder into a first volume and a second volume, the first volume is operatively connected to a first piezo electric pump that increases a first pressure in the first volume and the second volume is operatively connected to a second piezo electric pump that increases a second pressure in the second volume, such that a relative displacement of the piston is determined by a pressure balance between the first pressure and the second pressure, and at least one of the first volume and the second volume has a vent valve to release the first pressure in the first volume and the second pressure in the second volume to suspend the pressure balance and thereby directly displace the piston by increasing the first pressure in the first volume via the first piezo electric pump or the second pressure in the second volume via the second piezo electric pump.