Patent ID: 7093418

Claim:
A gas turbine engine, comprising: a compressor section and a turbine section mounted in flow series, the compressor section including at least a low pressure compressor and a high pressure compressor, each compressor having an air inlet and an air outlet; a housing that at least partially surrounds the compressor section and the turbine section, the housing configured to define a lubrication sump, a buffer cavity, a vent cavity, and a high pressure air cavity in fluid communication with the high pressure compressor air outlet and the turbine section; a lubrication sump disposed between the compressor section and the turbine section, the lubrication sump adapted to receive a flow of lubricant; one or more sump seals coupled to the lubrication sump and at least partially exposed to the buffer cavity; one or more vent seals disposed between the buffer cavity and the vent cavity, the vent seals configured to allow fluid flow at least from the buffer cavity to the vent cavity, the vent seals configured to allow fluid flow at least from the buffer cavity to the vent cavity; one or more throttle seals disposed between the vent cavity and the high pressure cavity, the throttle seals configured to allow fluid flow at least from the high pressure cavity to the vent cavity; and a buffer air supply passage having an inlet in fluid communication with the low pressure compressor air outlet and an outlet in fluid communication with the sump seals, whereby air from the low pressure compressor is used to buffer the sump seals to thereby substantially prevent lubricant from leaking from the lubrication sump.