Patent ID: 7836675

Claim:
Active air pressure control apparatus for a bearing sump cavity in a gas turbine engine comprising: a bearing assembly supporting a rotatable shaft connecting a rotatable power turbine and a rotatable compressor; a sump cavity surrounding said bearing assembly; a sump pressurization cavity in flow communication with a source of pressurized air and in flow communication with said sump cavity via a labyrinth seal configured to minimize oil leakage into an interior cavity of said gas turbine engine; a sump vent tube in flow communication with said sump cavity and an air/oil separator; an adjustable valve positioned in said sump vent tube, capable of being set in said adjustable valve selectively positionable to one of a fully open position and a partially closed position; and a controllable blower in flow communication with said sump vent tube, wherein said controllable blower is turned off when the adjustable valve is set in the partially closed position and turned on when the adjustable valve is set to the fully open position.