Patent ID: 8414255

Claim:
A turbine casing impingement cooling arrangement for a gas turbine engine, the arrangement comprising: at least part of a casing configured to define a flowpath for the passage of hot gases through the engine; and a manifold spaced from said casing so as to define a space between the manifold and the outer surface of the casing, the manifold comprising a baffle extending at least partially across said space, substantially towards said casing, so as to at least partially divide said space into a first region adjacent a first area and a second region adjacent a second area, the manifold being configured to: direct cooling air against an outer surface of the casing for impingement cooling thereof; direct a primary flow of cooling air against said first area of the casing outer surface for impingement cooling of said first area; recirculate at least a portion of said primary flow of cooling air after impingement against said first area; and direct at least a portion of the recirculated flow against said second area of the casing outer surface for impingement cooling of said second area.