Abstract: An intershaft seal assembly for use between an inner shaft and an outer shaft within a turbine engine is presented. The seal assembly includes a sealing ring, centrifugal retaining plates, and end rings. The sealing ring further includes a plurality of asymmetric ring segments whereby each asymmetric ring segment further includes a vertical flange and horizontal flanges extending from the vertical flange in a non-symmetric arrangement. At least one slot is disposed along each horizontal flange. The sealing ring is interposed between the centrifugal retaining plates. Each centrifugal retaining plate includes a plurality of tabs extending therefrom. Each tab is engaged by one slot. The sealing ring and the centrifugal retaining plates are interposed between the end rings. Each centrifugal retaining plate is directly interposed between one horizontal flange and one end ring. The vertical flange extends from between the end rings in the direction of the outer shaft.

Abstract: A circumferential seal assembly capable of dividing a gas into separate flow paths before communication between a rotatable runner and a pair of seal rings is presented. The assembly includes an annular seal housing, a rotatable runner, a pair of annular seal rings, and a plurality of groove structures. Each groove structure separates a source flow communicated into a feed groove so that a portion enters at least two grooves to form a longitudinal flow therein. Each groove includes at least two adjoining steps defined by base walls. The base walls are arranged along the groove to decrease depthwise opposite to rotation of the rotatable runner. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects the longitudinal flow to form an outward radial flow in the direction of one annular seal ring. The base walls are bounded by and intersect a pair of side walls.

Abstract: A circumferential seal assembly capable of separating a gas into two separate flow paths before communication between a rotatable runner and a pair of seal rings is presented. The seal assembly includes an annular seal housing, a pair of annular seal rings, a rotatable runner, and a plurality of groove structures. The seal housing is interposed between a pair of compartments. The seal rings are separately disposed within the seal housing and separately disposed around the rotatable runner. The groove structures are disposed along an outer annular surface of the rotatable runner. A gas is communicable onto the groove structures. Each groove structure includes at least two hydrodynamic grooves that separate and communicate the gas onto the seal rings. Each groove includes steps whereby the depth of at least one adjoining step decreases in the direction opposite to rotation with or without the depth of another adjoining steps increasing in the direction opposite to rotation.

Abstract: A circumferential seal assembly capable of separating a gas into two separate flow paths before communication between a rotatable runner and a pair of seal rings is presented. The seal assembly includes an annular seal housing, a pair of annular seal rings, a rotatable runner, and a plurality of groove structures. The seal housing is interposed between a pair of compartments. The seal rings are separately disposed within the seal housing and separately disposed around the rotatable runner. The groove structures are disposed along an outer annular surface of the rotatable runner. A gas is communicable onto the groove structures. Each groove structure includes at least two hydrodynamic grooves that separate and communicate the gas onto the seal rings. Each groove includes steps whereby the depth of at least one adjoining step decreases in the direction opposite to rotation with or without the depth of another adjoining steps increasing in the direction opposite to rotation.

Abstract: An intershaft seal assembly for use between an inner shaft and an outer shaft within a turbine engine is presented. The seal assembly includes a sealing ring, centrifugal retaining plates, and end rings. The sealing ring further includes a plurality of asymmetric ring segments whereby each asymmetric ring segment further includes a vertical flange and horizontal flanges extending from the vertical flange in a non-symmetric arrangement. At least one slot is disposed along each horizontal flange. The sealing ring is interposed between the centrifugal retaining plates. Each centrifugal retaining plate includes a plurality of tabs extending therefrom. Each tab is engaged by one slot. The sealing ring and the centrifugal retaining plates are interposed between the end rings. Each centrifugal retaining plate is directly interposed between one horizontal flange and one end ring. The vertical flange extends from between the end rings in the direction of the outer shaft.

Abstract: An intershaft seal assembly for use between an inner shaft and an outer shaft rotatable within a turbine engine is presented. The seal assembly includes a sealing ring, an inner ring, and a pair of end rings. The sealing ring further includes a plurality of asymmetric ring segments whereby each asymmetric ring segment further includes a vertical flange and a pair of horizontal flanges extending from the vertical flange in a non-symmetric arrangement. The non-symmetric seal geometry provides an axial force balance thereby reducing wear and increasing seal life. The sealing ring is disposed about the inner ring. The inner ring includes a plurality of ridges that engage the asymmetric ring segments so as to prevent rotation of the asymmetric ring segments with respect to the inner shaft. The end rings are disposed about the sealing ring and the inner ring.

Abstract: An intershaft seal assembly for use between an inner shaft and an outer shaft rotatable within a turbine engine is presented. The seal assembly includes a sealing ring, an inner ring, and a pair of end rings. The sealing ring further includes a plurality of asymmetric ring segments whereby each asymmetric ring segment further includes a vertical flange and a pair of horizontal flanges extending from the vertical flange in a non-symmetric arrangement. The non-symmetric seal geometry provides an axial force balance thereby reducing wear and increasing seal life. The sealing ring is disposed about the inner ring. The inner ring includes a plurality of ridges that engage the asymmetric ring segments so as to prevent rotation of the asymmetric ring segments with respect to the inner shaft. The end rings are disposed about the sealing ring and the inner ring.

Abstract: The disclosure describes a windback device for a circumferential seal within a turbine engine. The windback device includes an annular collar at one end of an annular fluid seal housing, at least one inclined thread, and a plurality of inclined baffles separately disposed along an outer circumferential surface of a rotatable runner. The housing is adapted at another end for an annular seal. The collar has an opening therethrough sized to receive the runner without contact. The annular seal surrounds and sealingly engages the runner. The threads extend from an inner face of the collar toward the runner. The baffles are separately recessed in or raised above the outer circumferential surface of the runner. The baffles are interposed between the runner and threads. Each baffle is separated from the threads via a radial clearance. Threads and baffles direct lubricant away from the annular seal.

Abstract: A circumferential seal assembly capable of separating a gas into two separate flow paths before communication between a rotatable runner and a pair of seal rings is presented. The seal assembly includes an annular seal housing, a pair of annular seal rings, a rotatable runner, and a plurality of groove structures. The seal housing is interposed between a pair of compartments. The seal rings are separately disposed within the seal housing and separately disposed around the rotatable runner. The groove structures are disposed along an outer annular surface of the rotatable runner. A gas is communicable onto the groove structures. Each groove structure includes at least two hydrodynamic grooves that separate and communicate the gas onto the seal rings. Each groove includes steps whereby the depth of at least one adjoining step decreases in the direction opposite to rotation with or without the depth of another adjoining steps increasing in the direction opposite to rotation.

Abstract: A circumferential seal assembly capable of separating a gas into two separate flow paths before communication onto a pair of seal rings is presented. The seal assembly includes an annular seal housing, a pair of annular seal rings, a rotatable runner, and a plurality of groove structures. The seal housing is interposed between a pair of low pressure compartments. The seal rings are separately disposed within the seal housing and separately disposed around the rotatable runner. The groove structures are disposed along an outer circumferential surface of the rotatable runner. The gas is communicable onto the groove structures. Each groove structure bifurcates the gas before communication onto the seal rings. Flow within each groove structure may be further separable before the gas is communicated onto the seal rings. The gas forms a thin-film layer between the rotatable runner and each seal ring.

Abstract: The disclosure describes a windback device for a circumferential seal within a turbine engine. The windback device includes an annular collar at one end of an annular fluid seal housing, at least one inclined thread, and a plurality of inclined baffles separately disposed along an outer circumferential surface of a rotatable runner. The housing is adapted at another end for an annular seal. The collar has an opening therethrough sized to receive the runner without contact. The annular seal surrounds and sealingly engages the runner. The threads extend from an inner face of the collar toward the runner. The baffles are separately recessed in or raised above the outer circumferential surface of the runner. The baffles are interposed between the runner and threads. Each baffle is separated from the threads via a radial clearance. Threads and baffles direct lubricant away from the annular seal.

Abstract: A circumferential seal assembly capable of separating a gas into two separate flow paths before communication onto a pair of seal rings is presented. The seal assembly includes an annular seal housing, a pair of annular seal rings, a rotatable runner, and a plurality of groove structures. The seal housing is interposed between a pair of low pressure compartments. The seal rings are separately disposed within the seal housing and separately disposed around the rotatable runner. The groove structures are disposed along an outer circumferential surface of the rotatable runner. The gas is communicable onto the groove structures. Each groove structure bifurcates the gas before communication onto the seal rings. Flow within each groove structure may be further separable before the gas is communicated onto the seal rings. The gas forms a thin-film layer between the rotatable runner and each seal ring.

Abstract: The disclosure describes a windback device for a circumferential seal within a turbine engine. The windback device includes an annular collar at one end of an annular fluid seal housing, at least one inclined thread, and a plurality of inclined baffles separately disposed along an outer circumferential surface of a rotatable runner. The housing is adapted at another end for an annular seal. The collar has an opening therethrough sized to receive the runner without contact. The annular seal surrounds and sealingly engages the runner. The threads extend from an inner face of the collar toward the runner. The baffles are separately recessed in or raised above the outer circumferential surface of the runner. The baffles are interposed between the runner and threads. Each baffle is separated from the threads via a radial clearance. Threads and baffles direct lubricant away from the annular seal.

Abstract: An intershaft seal system capable of communicating a balanced pressure profile onto forward and aft faces along a piston ring is presented. The seal system includes forward and aft mating rings and a piston ring. Mating rings include a plurality of divergent flow grooves adjacent to the piston ring. Each divergent flow groove includes a pair of grooves which intersect at and are substantially symmetric about an apex. The piston ring includes channels which direct a fluid from a high pressure region upward or downward and through the piston ring and onto the divergent flow grooves. The divergent flow grooves separate the fluid in a symmetrically divergent fashion prior to communication onto the piston ring. The divergent flow grooves communicate a substantially symmetric pressure force onto each side of the piston ring so as to minimize twist thereof, thus reducing wear along the piston ring and increasing seal life.

Abstract: A segmented intershaft seal assembly for use between inner and outer shafts within a turbine engine is presented. The intershaft seal assembly includes annular end rings, an annular seal element with an inverted “T”-shaped cross section, at least one resilient element, an annular spacer ring, carriers, counterweights, and hydrodynamic grooves. The intershaft seal assembly is secured to the inner shaft. The resilient element(s) biases seal segments away from the inner shaft toward the outer shaft. The counterweights are disposed about the seal segments and substantially negate forces imposed by the seal segments outward toward the outer shaft. The hydrodynamic grooves are disposed along an inner annular surface of the outer shaft and direct fluid onto an outer surface along the seal segments when the outer shaft rotates. The hydrodynamic grooves form a thin-film layer and non-contact seal that separates the seal segments from the outer shaft which otherwise provide a contact-type seal.

Abstract: An improved air-riding seal system for turbine engines is presented. The seal system includes a movable primary seal assembly, a stationary secondary seal assembly, and at least one structure to increase the stiffness of a thin film between the primary seal and a rotating component. The primary seal assembly includes an annular seal ring and an arcuate support arm. The annular seal ring has a cross section that is substantially L-shaped and a surface with a step face and a circumferential dam. The arcuate support arm has a tooth at one end adjacent to an outermost circumferential surface along the seal runner, which could include an optional notch. The tooth and outermost circumferential surface are separated by a gap. The secondary seal ring is disposed between and contacts the primary seal assembly and housing structure so as to form a bore seal and a face seal therewith.

Abstract: The present invention relates to circumferential seal ring segments positioned around a rotating shaft so as to prevent fluids from leaking from a lubricant sump during both low and high pressure conditions. The circumferential seal is comprised of a plurality of adjoining annular ring segments facing the rotating shaft. Each sealing ring segment includes a dead end circumferential groove on a shaft-side face of each sealing ring such that, when the segments are joined, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation. At least one additional groove is contained on the shaft-side face of each sealing ring segment. The additional groove(s) directs and creates pressurized air within the dead end circumferential groove, either directly or indirectly maintaining a seal between the ring segments and the shaft. A bleed hole may also be provided to create a seal between each sealing segment.

Abstract: A segmented intershaft seal assembly for use between inner and outer shafts within a turbine engine is presented. The intershaft seal assembly includes annular end rings, an annular seal element with an inverted “T”-shaped cross section, at least one resilient element, an annular spacer ring, carriers, counterweights, and hydrodynamic grooves. The intershaft seal assembly is secured to the inner shaft. The resilient element(s) biases seal segments away from the inner shaft toward the outer shaft. The counterweights are disposed about the seal segments and substantially negate forces imposed by the seal segments outward toward the outer shaft. The hydrodynamic grooves are disposed along an inner annular surface of the outer shaft and direct fluid onto an outer surface along the seal segments when the outer shaft rotates. The hydrodynamic grooves form a thin-film layer and non-contact seal that separates the seal segments from the outer shaft which otherwise provide a contact-type seal.

Abstract: The disclosure describes a windback device for a circumferential seal within a turbine engine. The windback device includes an annular collar at one end of an annular fluid seal housing, at least one inclined thread, and a plurality of inclined baffles separately disposed along an outer circumferential surface of a rotatable runner. The housing is adapted at another end for an annular seal. The collar has an opening therethrough sized to receive the runner without contact. The annular seal surrounds and sealingly engages the runner. The threads extend from an inner face of the collar toward the runner. The baffles are separately recessed in or raised above the outer circumferential surface of the runner. The baffles are interposed between the runner and threads. Each baffle is separated from the threads via a radial clearance. Threads and baffles direct lubricant away from the annular seal.

Abstract: The present invention relates to circumferential seal ring segments positioned around a rotating shaft so as to prevent fluids from leaking from a lubricant sump during both low and high pressure conditions. The circumferential seal is comprised of a plurality of adjoining annular ring segments facing the rotating shaft. Each sealing ring segment includes a dead end circumferential groove on a shaft-side face of each sealing ring such that, when the segments are joined, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation. Additional grooves are contained on the shaft-side face of each sealing ring segment. The additional grooves direct and create pressurized air within the dead end circumferential groove, either directly or indirectly maintaining a seal between the ring segments and the shaft.