Abstract: A circumferential seal assembly for use between a higher pressure side and a lower pressure side is presented. The seal assembly includes a primary sealing ring, a second sealing ring, a third sealing ring, and an insert. The primary sealing ring sealingly engages both a face sealing surface along a housing and a radial sealing surface along a rotatable element. The primary sealing ring, the second sealing ring, and the third sealing ring cooperate, in combination with the housing, the rotatable element, and/or the insert, both to define and to separate a first cavity at the higher pressure side and a second cavity at the lower pressure side. In some embodiments, the second sealing ring sealingly engages a face of the primary sealing ring. In other embodiments, the second sealing ring sealingly engages a circumferential surface of the primary sealing ring.

Abstract: A circumferential seal assembly suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes side shoulders which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.

Abstract: An intershaft seal assembly for use between a rotatable outer structure and an inner structure within a turbine engine is presented. The assembly includes a primary sealing ring, a translatable carrier, a secondary sealing ring(s), a lower-pressure chamber, a higher-pressure chamber, a first channel(s), and a second channel(s). The primary ring is disposed within and extends from a circumferential groove about the carrier so as to sealingly engage the rotatable outer structure. The primary ring rotates within the groove and with the rotatable outer structure. Each secondary ring is interposed between the carrier and the inner structure. The carrier slidingly contacts the secondary ring(s). The lower-pressure chamber is generally defined by the carrier and the inner structure adjacent to a higher-pressure side. The higher-pressure chamber is generally defined by the carrier and the inner structure adjacent to a lower-pressure side.

Abstract: A circumferential seal assembly suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes side shoulders which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.

Abstract: A circumferential seal assembly for use between a higher pressure side and a lower pressure side is presented. The seal assembly includes a primary sealing ring, a second sealing ring, a third sealing ring, and an insert. The segmented primary sealing ring sealingly engages both a face sealing surface along a housing and a radial sealing surface along a rotatable element. The insert is disposed within and directly contacts the housing. The second sealing ring is adjacent to the primary sealing ring and sealingly engages both the primary sealing ring and the insert. The segmented third sealing ring contacts and sealingly engages the primary sealing ring opposite the housing. The insert, the second sealing ring, and the third sealing ring cooperate to form a first cavity adjacent to the second sealing ring and the third sealing ring. The primary sealing ring, the second sealing ring, the insert, and the housing cooperate to form a second cavity adjacent to the primary sealing ring.

Abstract: A circumferential sealing assembly for use between a lower-pressure side with a lubricant oil therein and a higher-pressure side with a hot gas therein is presented. The assembly includes a sealing ring interposed between either a rotatable runner and a housing or a sleeve and a housing within a turbine engine. Ducts communicate the hot gas into grooves to form a thin film between the ring and the runner or the ring and the sleeve. First embodiments include grooves on the runner, ducts through the runner, and both grooves and ducts rotating with the runner. Second embodiments include grooves on the ring, ducts through the runner, and ducts rotating with the runner. Third embodiments include grooves on the ring and ducts through the ring adjacent to a runner. Fourth embodiments include grooves on the runner, ducts through the ring, and grooves rotating with the runner. Fifth embodiments include grooves on the sleeve, ducts through the sleeve, and both grooves and ducts rotating with the sleeve.

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 suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes at least one side shoulder which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.

Abstract: A circumferential seal assembly for use between a higher pressure side and a lower pressure side is presented. The seal assembly includes a primary sealing ring, a second sealing ring, a third sealing ring, and an insert. The segmented primary sealing ring sealingly engages both a face sealing surface along a housing and a radial sealing surface along a rotatable element. The insert is disposed within and directly contacts the housing. The second sealing ring is adjacent to the primary sealing ring and sealingly engages both the primary sealing ring and the insert. The segmented third sealing ring contacts and sealingly engages the primary sealing ring opposite the housing. The insert, the second sealing ring, and the third sealing ring cooperate to form a first cavity adjacent to the second sealing ring and the third sealing ring. The primary sealing ring, the second sealing ring, the insert, and the housing cooperate to form a second cavity adjacent to the primary sealing ring.

Abstract: An intershaft seal assembly for maintaining separation between a piston ring and a pair of mating rings is presented. The assembly includes a piston ring interposed between forward and aft mating rings and a plurality of hydrodynamic grooves disposed along a sealing face of each mating ring. Each hydrodynamic groove further includes at least two adjoining steps wherein each step is defined by a base wall arranged to decrease depthwise in the direction opposite to rotation of an inner shaft. Two adjoining base walls define a base shoulder which locally redirects potion of a longitudinal flow within the groove to form an outward flow in the direction of the piston ring. Base walls are bounded by and intersect a pair of side walls with at least one side shoulder thereon which narrows the groove widthwise and locally redirects portion of the longitudinal flow to form a lateral flow from one side wall toward another side wall.

Abstract: A slurry seal assembly for use about a rotatable shaft between a process side and an atmosphere side is presented. The slurry seal assembly includes a sleeve, a rotatable seal ring, a stationary seal ring, a floating bushing seal assembly, and a plurality of slots. The sleeve is disposed about and rotatable with the shaft. The rotatable seal ring contacts and is rotatable with the sleeve. The stationary seal ring is arranged to form a sealing interface with the rotatable seal ring. The floating bushing seal assembly is disposed about the sleeve so that an inner annular surface along the floating bushing seal assembly is separated from an outer annular surface along the sleeve by a gap. The slots are disposed along the sleeve within the process side adjacent to the floating bushing seal assembly. The slurry seal assembly is applicable to devices whereby a fluid is movable between an inlet and an outlet.

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 slurry seal assembly for use about a rotatable shaft between a process side and an atmosphere side is presented. The slurry seal assembly includes a sleeve, a rotatable seal ring, a stationary seal ring, a floating bushing seal assembly, and a plurality of slots. The sleeve is disposed about and rotatable with the shaft. The rotatable seal ring contacts and is rotatable with the sleeve. The stationary seal ring is arranged to form a sealing interface with the rotatable seal ring. The floating bushing seal assembly is disposed about the sleeve so that an inner annular surface along the floating bushing seal assembly is separated from an outer annular surface along the sleeve by a gap. The slots are disposed along the sleeve within the process side adjacent to the floating bushing seal assembly. The slurry seal assembly is applicable to devices whereby a fluid is movable between an inlet and an outlet.

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: 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 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 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: A segmented intershaft seal assembly for counter-rotating and co-rotating turbine engines is described. The assembly includes a pair of end rings, an annular seal element, and at least one resilient element. At least one end ring has a flange that extends from one side thereof. The flange has a lower annular surface. The seal element includes at least two seal segments. Each seal segment includes a ring segment and a ring flange segment. The ring segment has an upper radial surface. The ring flange segment directly contacts and extends from the upper radial surface forming either a substantially “T”-shaped or “L”-shaped cross section. The seal segments are disposed between the end rings. At least one resilient element biases each seal segment away from the inner shaft so that the upper radial surface contacts the lower annular surface and a portion of the ring flange segment extends beyond the flanges.