Air-oil separators for use in gas turbine engines

Claim 1

IN A GAS TURBINE ENGINE HAVING A MAIN SHAFT ROTATABLY MOUNTED IN A SERIES OF BEARINGS LUBRICATED BY OIL FROM A LUBRICATION SYSTEM AND AN ACCESSORY DRIVE SYSTEM POWERED FROM SAID MAIN SHAFT, SAID LUBRICATION SYSTEM COMPRISING: A SUMP CHAMBER SURROUNDING EACH OF SAID BEARINGS AND HAVING AT LEAST ONE OPENING THROUGH WHICH SAID MAIN SHAFT EXTENDS, MEANS FOR DELIVERING LUBRICATING OIL TO SAID BEARINGS, SEAL MEANS FOR PREVENTING LOSS OF OIL FROM SAID SUMP CHAMBERS THROUGH SAID OPENING, MEANS FOR SCAVENGING SAID LUBRICATING OIL FROM EACH OF SAID SUMP CHAMBERS, MEANS FOR PRESSURIZING THE EXTERIOR OF SAID SEALING MEANS WITH AIR TO PRESSURE HIGHER THAN THAT IN SAID SUMP AND CAUSING A FLOW ACROSS SAID SEALING MEANS, THEREBY PREVENTING LOSS OF OIL THEREFROM, SAID SUMP CHAMBERS HAVING AN OUTLET FOR VENTING AIR THEREFROM TO MAINTAIN AT LEAST A MINIMUM PRESSURE DIFFERENTIAL ACROSS SAID SEALS, AND SAID ACCESSORY DRIVE SYSTEM COMPRISES: A HOUSING, A SHAFT ROTATABLE IN SAID HOUSING AND HAVING THEREON A SPUR GEAR MESHING WITH ANOTHER GEAR OF A GEAR TRAIN, MEANS FOR SCAVENGING OIL FROM SAID HOUSING, THE IMPROVEMENT WHICH COMPRISES CONDUIT MEANS CONNECTING ALL OF SAID SUMP CHAMBER OUTLETS TO SAID HOUSING FOR DISCHARGE THERETO OF VENT AIR, PASSAGEWAY MEANS FOR DISCHARGE OF SAID VENT AIR FROM SAID HOUSING COMPRISING A PLURALITY OF RADIALLY EXTENDING PASSAGES IN SAID SHAFT ADJACENT ONE SIDE OF SAID GEAR AND AN AXIAL PASSAGE THEREIN CONNECTING WITH SAID RADIAL PASSAGES AND EXTENDING TO ONE END OF SAID SHAFT, WHEREBY AS SAID VENT AIR PASSES BY SAID GEAR AND THROUGH SAID RADIAL PASSAGES IT IS ACCELERATED TANGENTIALLY TO GENERATE SUFFICIENT CENTRIFUGAL FORCE ON OIL ENTRAINED THEREIN TO FORCE IT OUTWARDLY TOWARD THE WALLS OF SAID HOUSING FOR REMOVAL FROM SAID HOUSING BY SAID SCAVENGING MEANS AND SAID AIR PASSES TO SAID AXIAL PASSAGE FOR DISCHARGE THEREFROM.