# US 2014/0154053 A1 · Carbon seal assembly > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0154053 A1 - Document ID: US20140154053A1 - Status: Published application - Kind: A1 - Application number: 13/705,259 - Filed: 2012-12-05 - Published: 2014-06-05 - Earliest claimed: 2012-12-05 - Assignees: Pratt & Whitney Canada Corp. - Applicants: Pratt & Whitney Canada Corp. - Inventors: Ivor John Roberts - Web page: https://patentgrep.com/patent/US20140154053A1 ## CPC - F01D 11/00: Preventing or minimising internal leakage of working-fluid, e.g. between stages (sealings in general F16J {; sealing arrangements for transition ducts of combustor cans F01D9/023}) - F02C 7/28: Arrangement of seals - F16J 15/3444: {by magnetic attraction} - F05D 2240/55: Seals - F05D 2300/224: Carbon, e.g. graphite - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - 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) - F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A carbon seal assembly comprises an annular member adapted to be secured to a structure. An annular seal runner is sealingly mounted to a shaft to rotate therewith, with the seal runner being made of a material complementary to that of the annular member for magnetic attraction therebetween. An annular carbon seal element is mounted to the annular seal runner to rotate therewith and positioned in a gap between the annular member and the annular seal runner, the annular carbon seal element having an annular wear surface abutting against a face of the annular member. A cross-sectional area of the annular carbon seal element increases as the axial dimension of the annular seal runner decreases for at least a part of the seal. ## Claims ### Claim 1 A carbon seal assembly comprising: an annular member adapted to be secured to a structure; an annular seal runner adapted to be sealingly mounted to a shaft to rotate therewith, with the seal runner being made of a material complementary to that of the annular member for magnetic attraction therebetween; and an annular carbon seal element mounted to the annular seal runner to rotate therewith and positioned in a gap between the annular member and the annular seal runner, the annular carbon seal element having an annular wear surface abutting against a face of the annular member, a cross-sectional area of the annular carbon seal element increasing as the axial dimension of the annular seal runner decreases for at least a part of the seal. ### Claim 2 (depends on 1) The carbon seal assembly according to claim 1, wherein the entirety of the sectional shape of the annular carbon seal element has the increasing radial dimension along the axial direction of the annular carbon seal element from the annular wear surface toward the annular seal runner. ### Claim 3 (depends on 1) The carbon seal assembly according to claim 1, wherein the annular carbon element has a leading sectional shape portion and a trailing sectional shape portion with the leading sectional shape portion being adjacent to the annular member in the axial direction. ### Claim 4 (depends on 3) The carbon seal assembly according to claim 3, wherein the leading sectional shape portion has a trapezoid shape with an outer side and an inner side being oblique relative to the axial direction. ### Claim 5 (depends on 3) The carbon seal assembly according to claim 3, wherein the trailing sectional shape portion has a trapezoid shape with an outer side parallel to the axial direction, and an inner side being oblique relative to the axial direction. ### Claim 6 (depends on 5) The carbon seal assembly according to claim 5, wherein the outer side of the trailing sectional shape portion is in abutment with a counterbore surface of the annular seal runner. ### Claim 7 (depends on 1) The carbon seal assembly according to claim 1, wherein the sectional shape of the annular carbon seal element is a five-sided polygonal shape. ### Claim 8 (depends on 1) The carbon seal assembly according to claim 1, wherein the annular carbon seal element is made of hard matter carbon. ### Claim 9 (depends on 1) The carbon seal assembly according to claim 1, wherein the annular member is made of a magnetic material, and wherein the annular seal runner is made of a metallic material attracted to the magnetic material. ### Claim 10 (depends on 1) The carbon seal assembly according to claim 1, further comprising at least one resilient annular seal between the annular seal runner and the shaft. ### Claim 11 An engine comprising: a structure; a shaft operatingly mounted to the structure to rotate relative to the structure; a carbon seal assembly comprising: an annular member secured to the structure; an annular seal runner sealingly mounted to the shaft to rotate therewith, with the seal runner being made of a material complementary to that of the annular member for magnetic attraction therebetween; and an annular carbon seal element mounted to the annular seal runner to rotate therewith and positioned in a gap between the annular member and the annular seal runner, the annular carbon seal element having an annular wear surface abutting against a face of the annular member, a cross-sectional area of the annular carbon seal element increasing as the axial dimension of the annular seal runner decreases for at least a part of the seal. ### Claim 12 (depends on 11) The engine according to claim 11, wherein the entirety of the sectional shape of the annular carbon seal element has the increasing radial dimension along the axial direction of the annular carbon seal element from the annular wear surface toward the annular seal runner. ### Claim 13 (depends on 11) The engine according to claim 11, wherein the annular carbon element has a leading sectional shape portion and a trailing sectional shape portion with the leading sectional shape portion being adjacent to the annular member in the axial direction. ### Claim 14 (depends on 13) The engine according to claim 13, wherein the leading sectional shape portion has a trapezoid shape with an outer side and an inner side being oblique relative to the axial direction. ### Claim 15 (depends on 13) The engine according to claim 13, wherein the trailing sectional shape portion has a trapezoid shape with an outer side parallel to the axial direction, and an inner side being oblique relative to the axial direction. ### Claim 16 (depends on 15) The engine according to claim 15, wherein the outer side of the trailing sectional shape portion is in abutment with a counterbore surface of the annular seal runner. ### Claim 17 (depends on 11) The engine according to claim 11, wherein the sectional shape of the annular carbon seal element is a five-sided polygonal shape. ### Claim 18 (depends on 11) The engine according to claim 11, wherein the annular carbon seal element is made of hard matter carbon. ### Claim 19 (depends on 11) The engine according to claim 11, wherein the annular member is made of a magnetic material, and wherein the annular seal runner is made of a metallic material attracted to the magnetic material. ### Claim 20 (depends on 11) The engine according to claim 11, further comprising at least one resilient annular seal between the annular seal runner and the shaft.