# US 10,502,141 B2 · Apparatus and method for controlling a pressure differential across a seal of a bearing chamber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,141 B2 - Document ID: US10502141B2 - Status: Granted - Kind: B2 - Application number: 15/446,521 - Filed: 2017-03-01 - Published: 2018-09-06 - Granted: 2019-12-10 - Earliest claimed: 2017-03-01 - Assignees: Pratt & Whitney Canada Corp. - Applicants: Pratt & Whitney Canada Corp. - Inventors: Adam Logan; Ritchie Domingo - Web page: https://patentgrep.com/patent/US10502141B2 ## CPC - F02C 7/28: Arrangement of seals - F01D 25/16: Arrangement of bearings; Supporting or mounting bearings in casings (bearings per se F16C) - F01D 25/183: {Sealing means} - F02C 7/06: Arrangements of bearings (bearings F16C); Lubricating ({of turbo machines F01D25/18; of machines or} engines in general F01M) - F02C 7/32: Arrangement, mounting, or driving, of auxiliaries - F16C 33/748: {flowing to or from the sealing gap, e.g. vacuum seals with differential exhaust} - F05D 2220/32: in gas turbines - F05D 2260/605: Venting into the ambient atmosphere or the like - F05D 2270/3015: differential pressure - F16C 33/6685: {Details of collecting or draining, e.g. returning the liquid to a sump} - F16C 33/7816: {Details of the sealing or parts thereof, e.g. geometry, material} - F16C 2360/23: Gas turbine engines - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract Apparatus and methods for controlling a pressure differential across one or more seals of a bearing chamber in a gas turbine engine are disclosed. In some embodiments, the apparatus comprises a scavenge pump in fluid communication with an interior of the bearing chamber for driving oil from the bearing chamber; and a venting valve. The venting valve is configured to cause venting of the interior of the bearing chamber in parallel to the scavenge pump based on the pressure differential across the one or more seals. ## Claims ### Claim 1 An apparatus for controlling a pressure differential across one or more seals of a bearing chamber in a gas turbine engine, the apparatus comprising: a scavenge pump in fluid communication with an interior of the bearing chamber for pumping oil from the bearing chamber; and a venting valve configured to controllably vent the interior of the bearing chamber in parallel to the scavenge pump based on the pressure differential across the one or more seals, wherein: the venting valve is configured to: cause venting of the interior of the bearing chamber when the pressure differential is less than a predetermined non-zero threshold; and substantially stop venting the interior of the bearing chamber when the pressure differential is greater than the predetermined non-zero threshold; and the venting valve comprises a biasing member urging a valve member toward an open position to cause venting of the interior of the bearing chamber, the biasing member providing a biasing force correlated to the predetermined non-zero threshold. ### Claim 2 (depends on 1) The apparatus as defined in claim 1, wherein the venting valve is configured to control venting of the interior of the bearing chamber based on a difference between a first pressure and a second pressure where the first pressure is indicative of a pressure of pressurized air supplied to an exterior of the one or more seals. ### Claim 3 (depends on 2) The apparatus as defined in claim 2, wherein the second pressure is a pressure at a position in fluid communication with the interior of the bearing chamber and between the one or more seals and the scavenge pump. ### Claim 4 (depends on 2) The apparatus as defined in claim 2, wherein the second pressure is a pressure at a position upstream of the scavenge pump. ### Claim 5 (depends on 2) The apparatus as defined in claim 2, wherein the second pressure is a pressure inside a scavenge line. ### Claim 6 (depends on 1) The apparatus as defined in claim 1, wherein: the valve member is movable to a plurality of positions between a fully-open position and a fully-closed position in correlation with the pressure differential across the one or more seals; a first side of the valve member is exposed to a first pressure indicative of a pressure of pressurized air supplied to an exterior of the one or more seals; and an opposite second side of the valve member is exposed to a second pressure, the second pressure being a pressure at a position in fluid communication with the interior of the bearing chamber and between the one or more seals and the scavenge pump. ### Claim 7 (depends on 1) The apparatus as defined in claim 1, wherein the venting valve is configured to cause venting of the bearing chamber into an accessory gear box of the gas turbine engine. ### Claim 8 (depends on 1) The apparatus as defined in claim 1, wherein the scavenge pump is a fixed displacement pump having a capacity selected to maintain a desired pressure differential across the one or more seals when the one or more seals are in a normal non-failed condition. ### Claim 9 (depends on 1) The apparatus as defined in claim 1, comprising a non-return valve operatively disposed between the venting valve and the bearing chamber to prevent backflow through the venting valve.