Seal assembly for a gas turbine regenerator

Claim 2

In a gas turbine engine having a regenerator rotating in a housing with sectors of said regenerator being subjected to gas streams of different pressures, a sealing system for said regenerator comprising a peripheral seal assembly extending around one of said sectors adjacent the rim of the regenerator and a crossarm seal assembly extending across the regenerator, the end portions of the crossarm seal assembly being adjacent the ends of the peripheral seal assembly, each of said seal assemblies including a shoe having a foil attached to a surface so the foil projects toward a portion of the housing, an end foil attached to each end of the crossarm seal assembly in substantial alignment with an end of the foil attached to the peripheral seal assembly, and, a secondary foil attached to each end portion of said peripheral seal assembly, each secondary foil being located behind the respective end foil of the crossarm seal assembly, each secondary foil having a concave shape behind its respective end foil and each secondary foil contacting sealingly its respective end foil at a location spaced along said concave shape depenDing on the relative thermal expansion of the crossarm assembly.

Claim 3

In a gas turbine engine having a regenerator rotating in a housing with sectors of said regenerator being subjected to gas streams of different pressures, a sealing system for said regenerator comprising a peripheral seal assembly extending around one of said sectors adjacent the rim of the regenerator and a crossarm seal assembly extending across the regenerator, the end portions of the crossarm seal assembly being adjacent the ends of the peripheral seal assembly, each of said seal assemblies including a shoe having a foil attached to a surface so the foil projects toward a portion of the housing, an end foil attached to each end of the crossarm seal assembly in substantial alignment with an end of the foil attached to the peripheral seal assembly, and, a secondary foil attached to each end portion of said peripheral seal assembly, each secondary foil being located behind the respective end foil of the crossarm seal assembly, each secondary foil having a concave shape behind its respective end foil and each secondary foil contacting sealingly its respective end foil at a location spaced along said concave shape depenDing on the relative thermal expansion of the crossarm assembly.

Claim 4

In a gas turbine engine having a regenerator rotating in a housing with sectors of said regenerator being subjected to gas streams of different pressures, a sealing system for said regenerator comprising a peripheral seal assembly extending around one of said sectors adjacent the rim of the regenerator and a crossarm seal assembly extending across the regenerator, the end portions of the crossarm seal assembly being adjacent the ends of the peripheral seal assembly, each of said seal assemblies including a shoe having a foil attached to a surface so the foil projects toward a portion of the housing, an end foil attached to each end of the crossarm seal assembly in substantial alignment with an end of the foil attached to the peripheral seal assembly, and, a secondary foil attached to each end portion of said peripheral seal assembly, each secondary foil being located behind the respective end foil of the crossarm seal assembly, each secondary foil having a concave shape behind its respective end foil and each secondary foil contacting sealingly its respective end foil at a location spaced along said concave shape depenDing on the relative thermal expansion of the crossarm assembly.

Claim 5

The engine of claim 1 comprising a second peripheral seal assembly extending around another of said sectors of the regenerator adjacent the rim of the regenerator, said second peripheral seal assembly including a shoe having a foil attached to a surface, the ends of said second peripheral seal assembly being separated from the ends of the first peripheral seal assembly by the end portions of the crossarm seal assembly, each of said secondary foils being attached to the appropriate ends of the first and second peripheral seal assemblies, said crossarm seal assembly being free to expand longitudinally relative to said peripheral seal assemblies.

Claim 6

The engine of claim 2 in which the regenerator is disc shaped and the exteriors of said peripheral seal assemblies are subjected during engine operation to a gas stream having a pressure higher than the pressures at the interiors of the peripheral seal assemblies.

Claim 7

The engine of claim 3 in which each secondary foil also contacts sealingly the respective ends of the foils of the peripheral seal assemblies.

Claim 8

The engine of claim 4 in which the radially inner edge of each secondary foil has a radius of curvature less than the radius of curvature of the peripheral seal assemblies.

Claim 9

The engine of claim 5 comprising a tab on each lateral end of each secondary foil, said tabs bearing against the respective end portions of the foils of the peripheral seal assemblies.

Claim 10

The engine of claim 6 comprising retainer straps staked to the end portions of the shoes of the peripheral shoe assemblies, each of said retainer straps spanning the respective end portion of the crossarm seal assembly.

Claim 11

The engine of claim 1 in which the regenerator is disc shaped and the exterior of the peripheral seal assembly is subjected during engine operation to a gas stream having a pressure higher than the pressure at the interior of the peripheral seal assembly.

Claim 12

The engine of claim 1 in which each secondary foil also contacts sealingly the respective end of the foil of the peripheral seal assembly.

Claim 13

The engine of claim 1 in which the radially inner edge of each secondary foil has a radius of curvature less than the radius of curvature of the peripheral seal assembly.

Claim 14

In a gas turbine engine having a regenerator rotating in a housing with sectors of said regenerator being subjected to gas streams of different pressures and the exterior of said regenerator being subjected to a gas pressure greater than the pressure in either sector, a sealing means for said regenerator comprising a peripheral shoe surrounding a portion of at least one of said sectors, said peripheral shoe having one surface sliding on said regenerator and the other surface adjacent a wall of said housing, a crossarm shoe dividing said sectors and having its end portions adjacent the end portions of said peripheral shoe so the peripheral shoe and the crossarm shoe surround completely one of said sectors, said cross-arm shoe having one surface sliding on said regenerator and the other surface adjacent a wall of said housing, a foil attached to said peripheral shoe and projecting outward and toward the adjacent wall of the housing, said foil being maintained in sealing contact with the adjacent wall by the gas pressure differential between the exterior of the regenerator and the sector, a foil attached to and extending longitudinally along said crossarm seal, said foil projecting toward an adjacent wall of the housing, said foil being maintained in sealing contact with the adjacent wall by a gas pressure differential, end foils attached to the end portions of the crossarm shoe, said end foils extending laterally across the end portions of the crossarm shoe in substantial alignment with the ends of the foil attached to the peripheral shoe, and a secondary foil positioned outside of each end foil, each of said secondary foils maintaining sealing contact wiTh its end foil despite thermally induced movement of the crossarm shoe relative to the peripheral shoe.

Claim 15

In a gas turbine engine having a regenerator rotating in a housing with sectors of said regenerator being subjected to gas streams of different pressures and the exterior of said regenerator being subjected to a gas pressure greater than the pressure in either sector, a sealing means for said regenerator comprising a peripheral shoe surrounding a portion of at least one of said sectors, said peripheral shoe having one surface sliding on said regenerator and the other surface adjacent a wall of said housing, a crossarm shoe dividing said sectors and having its end portions adjacent the end portions of said peripheral shoe so the peripheral shoe and the crossarm shoe surround completely one of said sectors, said cross-arm shoe having one surface sliding on said regenerator and the other surface adjacent a wall of said housing, a foil attached to said peripheral shoe and projecting outward and toward the adjacent wall of the housing, said foil being maintained in sealing contact with the adjacent wall by the gas pressure differential between the exterior of the regenerator and the sector, a foil attached to and extending longitudinally along said crossarm seal, said foil projecting toward an adjacent wall of the housing, said foil being maintained in sealing contact with the adjacent wall by a gas pressure differential, end foils attached to the end portions of the crossarm shoe, said end foils extending laterally across the end portions of the crossarm shoe in substantial alignment with the ends of the foil attached to the peripheral shoe, and a secondary foil positioned outside of each end foil, each of said secondary foils maintaining sealing contact wiTh its end foil despite thermally induced movement of the crossarm shoe relative to the peripheral shoe.

Claim 16

The engine of claim 11 comprising a second peripheral shoe surrounding another of said sectors and retainer straps having portions depressed into corresponding openings of the peripheral shoes to attach the peripheral shoes to each other, said retainer straps spanning the end portions of the crossarm shoe.