Patent ID: 7625171

Claim:
A cooling system for a gas turbine engine, the cooling system comprising a pre-swirl chamber, a pre-swirl arrangement for providing cooling air to a turbine blade disc, and a ventilation arrangement for providing ventilation air to a rotating component of the gas turbine engine, said cooling system including an air bypass arrangement for conveying ventilation air away from the pre-swirl arrangement, wherein the ventilation air is at a lower pressure than the cooling air and a portion of cooling air is conveyed into said air bypass arrangement from said pre-swirl chamber, said air bypass arrangement including a first air bypass duct portion, a second air bypass duct portion and a third air bypass duct portion wherein said third air bypass duct portion is defined in part by a static component of the gas turbine engine structure and wherein the third air bypass duct portion is further defined in part by a movable sealing component of the gas turbine engine.