Turbomachine stator interstage seal

Claim 2

A turbine stator comprising, in combination, an annular upstream shroud having a continuously circumferentially formed downstream edge; an annular downstream shroud coaxial with the upstream shroud having a continuously circumferentially formed upstream edge confronting the downstream edge of the upstream shroud; said downstream edge being axially spaced from said upstream edge throughout the full circumferential extent of both said downstream and upstream edges to form an open gap extending radially therebetween continuously circumferentially therebetween; the confronting edges of the shrouds defining opposed grooves in the confronting edges; and seal ring means operable to oppose gas flow through the gap between the shrouds, the seal ring means being a thin flexible coiled metallic strip extending substantially twice around the axis of the shrouds and axially across the gap and within the grooves to provide two layers, the layers being mutually slidable to accommodate relative radial expansion of the shrouds and strip for seating of a surface of the strip radially against the shrouds.

Claim 3

A turbine stator comprising, in combination, an annular upstream shroud having a continuously circumferentially formed downstream edge; an annular downstream shroud coaxial with the upstream shroud having a continuously circumferentially formed upstream edge confronting the downstream edge of the upstream shroud; said downstream edge being axially spaced from said upstream edge throughout the full circumferential extent of both said downstream and upstream edges to form an open gap extending radially therebetween continuously circumferentially therebetween; the confronting edges of the shrouds defining opposed grooves in the confronting edges; and seal ring means operable to oppose gas flow through the gap between the shrouds, the seal ring means being a thin flexible coiled metallic strip extending substantially twice around the axis of the shrouds and axially across the gap and within the grooves to provide two layers, the layers being mutually slidable in response to pressure difference across the gap to accommodate relative radial expansion of the shrouds and strip for seating of a surface of the strip radially against the shrouds.

Claim 4

A turbine stator comprising, in combination, an annular upstream shroud having a continuously circumferentially formed downstream edge; an annular downstream shroud coaxial with the upstream shroud having a continuously circumferentially formed upstream edge confronting the downstream edge of the upstream shroud; said downstream edge being axially spaced from said upstream edge throughout the full circumferential extent of both said downstream and upstream edges to form an open gap extending radially therebetween continuously circumferentially therebetween; the confronting edges of the shrouds defining opposed grooves in the confronting edges; and seal ring means operable to oppose gas flow through the gap between the shrouds, the seal ring means being a thin flexible coiled metallic strip extending substantially twice around the axis of the shrouds and axially across the gap and within the grooves to provide two layers, the layers being mutually slidable in response to pressure difference across the gap to accommodate relative radial expansion of the shrouds and strip for seating of a surface of the strip radially against the shrouds.

Claim 5

A turbine stator comprising, in combination, an annular upstream shroud having a continuously circumferentially formed downstream edge; an annular downstream shroud coaxial with the upstream shroud having an upstream edge confronting the downstream edge of the upstream shroud; the confronting edges of the shrouds defining opposed grooves in the confronting edges; and seal ring means operable to oppose gas flow through a gap between the shrouds, the seal ring means being a thin flexible coiled metallic strip extending substantially twice around the axis of the shrouds across the gap and within the grooves to provide two layers, the layers being mutually slidable to accommodate relative expansion of the shrouds and strip for seating of a surface of the strip radially against the shrouds, the strip having a thickness of the order of 1/40 millimeter.

Claim 6

A turbine stator comprising, in combination, an annular upstream shroud having a continuously circumferentially formed downstream edge; an annular downstream shroud coaxial with the upstream shroud having an upstream edge confronting the downstream edge of the upstream shroud; the confronting edges of the shrouds defining opposed grooves in the confronting edges; and seal ring means operable to oppose gas flow through a gap between the shrouds, the seal ring means being a thin flexible coiled metallic strip extending substantially twice around the axis of the shrouds across the gap and within the grooves to provide two layers, the layers being mutually slidable to accommodate relative expansion of the shrouds and strip for seating of a surface of the strip radially against the shrouds, the strip having a thickness of the order of 1/40 millimeter.