Patent ID: 7287955
Filing Date: 2007-10-30
Classification: F01D,F05D

Abstract:
1. A clearance control device for controlling clearance between rotary blade tips and a stationary bushing of a gas turbine, said stationary bushing including an annular casing that has a longitudinal axis and that is provided with at least two annular ridges axially spaced apart from each other and extending radially outwards of said casing, said clearance control device including a circular tuning unit that surrounds the casing of the stationary bushing, said tuning unit including: an air circulation device configured to circulate air, said air circulation device including at least three annular air flow ducts axially spaced apart one from another and disposed on either side of side faces of each of the ridges; an air supply device configured to supply air to the air flow ducts; and an air discharge mechanism configured to discharge air on the ridges in order to modify the temperature of the stationary bushing; wherein, for each air flow duct, the air discharge mechanism includes at least one top row having a number N of perforations disposed facing one of the side faces of the ridges and at least one bottom row having a number 2N of perforations aligned with each other on said bottom row along a perimeter of said air flow duct and disposed facing a connection radius that connects the ridges to the casing of the stationary bushing.