Abstract: An intershaft seal is provided for inner and outer coaxial shafts which rotate relative to each other. The seal is located in an annular space between the shafts and maintains an axial pressure differential between a fluid pressure on the first side of the seal and a different fluid pressure on the other, second side of the seal. The seal includes a first runner which extends circumferentially around a first one of the shafts and projects therefrom into the annular space. The seal further includes a sealing ring which is coaxial with the shafts.

Abstract: A leaf seal for effecting a seal between two, coaxial, relatively rotating components. The leaf seal has an annular pack of stacked leaves. The pack is mountable to a first one of the components with interleaf gaps formed between working portions of neighbouring leaves. The leaves extend towards the other component such that end edges of leaf working portions are presented for wiping contact with the other component. At least adjacent its end leaf edge, each leaf has a rear section at or adjacent the low pressure side of the pack and a front section which extends from the rear section to the high pressure side of the pack. The rear sections of the leaves are thicker than their respective front sections to reduce the interleaf gaps at the rear sections such that most of the pressure drop across the pack is over the rear sections.

Abstract: A leaf seal is provided for effecting a seal between two, coaxial, relatively rotating components. The leaf seal has an annular pack of stacked leaves. The pack is mountable to a first one of the components at root portions of the leaves and extends towards the other component such that end edges of the leaves are presented for wiping contact with the other component and, in use, a pressure drop is maintained axially across the pack. The leaf seal has a coverplate at the high or the low pressure side of the pack covering a portion of the radial extent of the pack. Some or all of the leaves have respective abutment formations. Each abutment formation is arranged to abut the coverplate at a stop portion upon radial deflection of the leaf by a predetermined amount to prevent further radial deflection beyond that amount.

Abstract: A leaf seal has a pair of annular packs of stacked leaves. Each pack is mountable to one of the components with its leaves extending towards the other component such that the leaf edges of at least one of the packs are presented for wiping contact with the other component. The packs are axially spaced from each other by a controlled axial clearance. Within each pack the leaves are stacked face-to-face such that neighboring leaves are separated from each other by interleaf gaps which allow an axial leakage flow through the seal. Further, within each pack the packs are positioned such that, when viewed in the axial direction, the leaves of each pack of the pair substantially obscure the interleaf gaps of the other pack of the pair. The controlled axial clearance is the dominant flow restriction in the seal determining the amount of leakage flow through the seal.

Abstract: A leaf seal is provided for effecting a seal between two coaxial, relatively rotating components. The leaf seal has an annular pack of leaves which are stacked face-to-face within the pack, and which are mountable to one of the components at respective root portions of the leaves such that the leaves extend towards the other component and respective edges of the leaves are presented for wiping contact with the other component. The pack includes a plurality of spacers, each spacer separating the root portions of neighboring leaves to form therebetween interleaf gaps which allow an axial leakage flow through the pack. The spacers are distributed around the pack such that the leaves are divided into blocks of two or more leaves sandwiched at their root portions between nearest-neighbor spacers.

Abstract: There is disclosed a rotary air-riding seal between a first structure and an adjacent second structure, including: first and second seal members defining respective seal surfaces facing to one another. The first seal member is provided on the first structure and the second seal member is mounted to the second structure towards the first seal member. At least one of said seal members is configured to generate a riding film of air between said seal surfaces. One of said seal members is supported for axial oscillation relative to the other seal member by a secondary support arrangement configured to bias said seal member towards the other seal member. The said secondary support arrangement accommodates relatively high frequency axial movements between the seal members.

Abstract: An intershaft seal is provided for inner and outer coaxial shafts which rotate relative to each other. The seal is located in an annular space between the shafts and maintains an axial pressure differential between a fluid pressure on a first side of the seal and a different fluid pressure on a second side of the seal. The seal includes first and second runners which project into the annular space from a first one of the shafts and extend circumferentially around the first shaft such that a cavity is formed between the runners. The seal further includes a sealing ring which is coaxial with the shafts and is located in the cavity.

Abstract: A process is provided for manufacturing leaf seals for effecting seals between coaxial, relatively rotating components. Each leaf seal has an annular pack of leaves which are stacked face-to-face, and are mountable to one of the components at respective root portions of the leaves. The annular pack has a pack radius at the wiping contact edges which is matched within tolerance limits to the radius of the sealing surface. The process includes: determining production parameters for the production of a plurality of leaf seals, the parameters being determined such that at least a portion of the produced leaf seals will have pack radii which violate the tolerance limit; producing the leaf seals using the determined production parameters; and modifying the pack radii of the portion of the produced leaf seals which violate the tolerance limit such that the modified pack radii match the sealing surface within the tolerance limits.

Abstract: There is disclosed a rotary air-riding seal between a first structure and an adjacent second structure, including: first and second seal members defining respective seal surfaces facing to one another. The first seal member is provided on the first structure and the second seal member is mounted to the second structure towards the first seal member. At least one of said seal members is configured to generate a riding film of air between said seal surfaces. One of said seal members is supported for axial oscillation relative to the other seal member by a secondary support arrangement configured to bias said seal member towards the other seal member. The said secondary support arrangement accommodates relatively high frequency axial movements between the seal members.

Abstract: An intershaft seal is provided for inner and outer coaxial shafts which rotate relative to each other. The seal is located in an annular space between the shafts and maintains an axial pressure differential between a fluid pressure on the first side of the seal and a different fluid pressure on the other, second side of the seal. The seal includes a first runner which extends circumferentially around a first one of the shafts and projects therefrom into the annular space. The seal further includes a sealing ring which is coaxial with the shafts.

Abstract: An intershaft seal is provided for inner and outer coaxial shafts which rotate relative to each other. The seal is located in an annular space between the shafts and maintains an axial pressure differential between a fluid pressure on a first side of the seal and a different fluid pressure on a second side of the seal. The seal includes first and second runners which project into the annular space from a first one of the shafts and extend circumferentially around the first shaft such that a cavity is formed between the runners. The seal further includes a sealing ring which is coaxial with the shafts and is located in the cavity.

Abstract: A leaf seal is provided for effecting a seal between two, coaxial, relatively rotating components. The leaf seal has an annular pack of stacked leaves. The pack is mountable to a first one of the components at root portions of the leaves and extends towards the other component such that end edges of the leaves are presented for wiping contact with the other component and, in use, a pressure drop is maintained axially across the pack. The leaf seal has a coverplate at the high or the low pressure side of the pack covering a portion of the radial extent of the pack. Some or all of the leaves have respective abutment formations. Each abutment formation is arranged to abut the coverplate at a stop portion upon radial deflection of the leaf by a predetermined amount to prevent further radial deflection beyond that amount.

Abstract: A method of forming a seal for effecting a seal between two, coaxial, relatively rotating components is provided. The seal has an annular pack of elongate flexible members. The pack is mountable to a first one of the components at the root portions of the flexible members and extending towards the other component. End portions of the flexible members are presented for wiping contact with the other component. The method includes the steps of: (i) forming a plurality of pack segments, wherein each segment contains a respective subset of the flexible members of the annular pack, and wherein the end portions of the flexible members of each subset, when viewed in the axial direction of the seal, lie on a straight line; and (ii) assembling the pack segments in a substantially circular pack holder such that each pack segment forms a respective angular sector of the annular pack.