Abstract: A coast down bushing having a plurality of grooves formed in the inner radial surface thereof. Each groove is filled with a lubricating insert or plug to reduce the contact friction between a rotating shaft and the bushing during coast down or during a rotor shock event or excursion.

Abstract: Coast-down bearing apparatus and methods are provided. The coast-down bearing includes a plurality of segments each having a radius of curvature substantially equal to an outer radius of a shaft and spaced radially therefrom to define a clearance, with the plurality of segments being configured to receive the shaft when a magnetic bearing drops the shaft. The coast-down bearing also includes a plurality of slots disposed between adjacent ones of the plurality of segments.

Abstract: A coast-down bearing and method for a magnetic bearing system is provided. The bearing includes first, second, and third rings disposed around a shaft. The first, second, and third rings each have an inner diameter that is greater than an outer diameter of the shaft and provide a running clearance therebetween. The first, second, and third rings are eccentrically positioned with respect to each other to form a pocket for receiving the shaft during a drop, radial shock, or both.

Abstract: Coast-down bearing apparatus and methods are provided. The coast-down bearing includes a plurality of segments each having a radius of curvature substantially equal to an outer radius of a shaft and spaced radially therefrom to define a clearance, with the plurality of segments being configured to receive the shaft when a magnetic bearing drops the shaft. The coast-down bearing also includes a plurality of slots disposed between adjacent ones of the plurality of segments.

Abstract: An apparatus for supporting a shaft of a turbomachine. The apparatus may include a magnetic bearing to support the shaft during a normal operation of the turbomachine, and an auxiliary bearing to support the shaft during a drop event. The apparatus may also include a disk coupled to the shaft and comprising a substantially non-ferrous, conductive material, and a magnetic assembly disposed proximal the disk, the magnetic assembly configured to magnetically engage the disk to damp vibrations during the drop event, to apply a circumferential braking force on the disk during the drop event, or both.

Abstract: A coast-down bearing and method for a magnetic bearing system is provided. The bearing includes first, second, and third rings disposed around a shaft. The first, second, and third rings each have an inner diameter that is greater than an outer diameter of the shaft and provide a running clearance therebetween. The first, second, and third rings are eccentrically positioned with respect to each other to form a pocket for receiving the shaft during a drop, radial shock, or both.

Abstract: An apparatus for supporting a shaft of a turbomachine. The apparatus may include a magnetic bearing to support the shaft during a normal operation of the turbomachine, and an auxiliary bearing to support the shaft during a drop event. The apparatus may also include a disk coupled to the shaft and comprising a substantially non-ferrous, conductive material, and a magnetic assembly disposed proximal the disk, the magnetic assembly configured to magnetically engage the disk to damp vibrations during the drop event, to apply a circumferential braking force on the disk during the drop event, or both.

Abstract: A sealing assembly configured to seal a rotating shaft of a turbo machine having a high pressure process gas, comprising a housing defining a bore configured to receive the rotating shaft and sealing assembly, wherein the housing is mounted to a casing of the turbo machine; a first sealing stage comprising a single dry gas seal and configured to blow down the high pressure process gas to a lower pressure; a labyrinth seal mounted longitudinally outward from the first sealing stage; and a second sealing stage mounted longitudinally outward from the labyrinth seal, wherein the second sealing stage comprises a tandem dry gas seal having a primary dry gas seal and a secondary dry gas seal axially spaced with an intermediate labyrinth seal.

Abstract: A sealing assembly configured to seal a rotating shaft of a turbo machine having a high pressure process gas, comprising a housing defining a bore configured to receive the rotating shaft and sealing assembly, wherein the housing is mounted to a casing of the turbo machine; a first sealing stage comprising a single dry gas seal and configured to blow down the high pressure process gas to a lower pressure; a labyrinth seal mounted longitudinally outward from the first sealing stage; and a second sealing stage mounted longitudinally outward from the labyrinth seal, wherein the second sealing stage comprises a tandem dry gas seal having a primary dry gas seal and a secondary dry gas seal axially spaced with an intermediate labyrinth seal.

Abstract: A bearing structure having an annular cage and an annular housing that optionally mate at frustogeometrical surfaces for supporting and positioning a rotatable shaft of a turbomachine and that optionally provides a squeeze film damper between the frustogeometrical surfaces of the annular cage and the annular housing. A bearing structure having an annular cage and an annular housing that optionally mate at frustogeometrical surfaces for supporting and positioning a rotatable shaft of a turbomachine and that optionally provides an externally adjustable squeeze film damper between the frustogeometrical surfaces of the annular cage and the annular housing. The squeeze film damper is defined by two annular squeeze film seals positioned in respective annular squeeze film seal grooves formed in the frustogeometrical radially outer surface of the annular cage. Lubricant is also delivered to the squeeze film damper which serves as the damping medium.

Abstract: An integral pivot pad bushing seal bearing, adapted for sealing about a rotating shaft, includes a carrier ring having a radially inner generally cylindrical surface for providing a fluid seal about the shaft. A plurality of cavities are formed in the carrier ring so as to open in the radially inner generally cylindrical surface. Each cavity contains a pivot pad having a radially inner generally cylindrical pad surface which is substantially flush with the radially inner generally cylindrical surface of the carrier ring. The carrier ring and the pivot pads are contained in the same axial length as a unitary structure and act together to both seal and support the shaft. Each cavity can have a longitudinally extending groove in its radially outermost portion for receiving high pressure fluid to press each pivot pad inwardly toward the shaft. A second groove, in communication with the first groove, can be formed in a cavity end wall to apply high pressure to an axial face of the pivot pad.

Abstract: A vaned diffuser is provided. The diffuser comprises a housing having a first and second flow wall defining a flow path for the exit flow from an impeller. Twisted vanes are mounted on a movable structure capable of travel inside a chamber adjacent the first flow wall. The twisted vanes extend through rotatable structures rotatably retained in the flow walls such that the twisted vanes are slidably disposed across the flow path. Lateral movement of the movable structure moves the twisted vanes through the exit flow thus varying the stagger angle of the vane depending on which section of the twisted vane is in the exit flow. The rotatable structures have twisted openings that match the vane cross-section and twist so that the rotatable structures readily rotate as the twisted vanes are moved through them.

Abstract: A shaft seal element (20) for use around a rotatable shaft (10) has an annular sealing surface (22) facing a radially adjacent surface of the shaft or housing. This sealing surface (22) can comprise two outer annular lands (26, 27) with an inner land (28) therebetween. A relief groove (29, 30) separates the inner land (28) from each outer land (26, 27). A plurality of fluid redirecting grooves (40) are obliquely formed across the inner land (28). A protruding ridge (44) is formed at the trailing edge (40b) of each redirecting groove (40). The ridges (44) and redirecting grooves (40) inhibit fluid migration across the sealing surface (22) and divert a portion of the fluid towards the high pressure end of the seal element.

Abstract: A squeeze film damper bearing (100) has the means of automatically centering itself from the force associated with lateral shaft vibration. It utilizes a floating ring (108) positioned between a housing (102) and a cage (106) with O-rings (115, 116, 130, 131) positioned between adjacent parts to maintain proper clearances. Oil is introduced into the clearances to serve as a damping medium. Squeeze film damping action occurs in the clearances when the force associated with lateral shaft vibration is transmitted from the shaft (120) through the radial bearing (114) to the damper oil films. The mating cylindrical surfaces between the flowing ring (108) and housing (102) have a common longitudinal axis 100a which is inclined with respect to the longitudinal shaft centerline 120a by an angle (122) which provides the means for the floating ring (108) to reposition itself so that it can assume a centered position with respect to the housing (102) and the cage (106) when subjected to lateral forces.

Abstract: A labyrinth seal which reduces the inlet swirl and circumferential flow of fluid within the sealing cavity of a rotating shaft system in order to eliminate the destabilizing influence of the labyrinth seal, has a plurality of primary flow bypass passageways which extend from the high pressure face of the seal to the space between a first set and a second set of labyrinth teeth. The plurality of primary flow bypass passageways are equally spaced around the circumference of the seal and are preferably inclined such that the fluid is introduced into the seal cavity at a desired orientation. Each of the primary flow bypass passageways can be a passageway which is inclined at an acute angle to the shaft axis or a combination of an axial passageway and a radial passageway. The primary flow bypass passageways can be in the form of a plurality of generally radial passageways which intersect a common annular opening in the high pressure face of the seal.

Abstract: A labyrinth seal is disclosed which reduces the inlet swirl and circumferential flow of fluid within the sealing cavity of a rotating shaft system. The primary purpose is to eliminate the destabilizing influence of the labyrinth seal which can induce rotor instability. This is accomplished by the addition of flow bypass passageways which extend from the high pressure face of the seal to the space between the first and second set of labyrinth teeth. The flow bypass passageways are equally spaced around the circumference of the seal and are inclined such that the fluid is introduced into the seal cavity at a desired orientation. Multiple sets of flow bypass passageways are also positioned at predetermined locations downstream from the first set of passages and function in a similar manner. Annular grooves are provided in the outer surface of the seal to connect each adjacent set of flow bypass passageways which straddle each set of labyrinth teeth.

Abstract: Support mechanism for fluid film seals in turbo machinery is disclosed which controls the relative position of a seal with respect to a shaft by a plurality of wedge support structures that are located between the seal and surrounding seal housing at predetermined circumferential locations. Each support structure consists of a pair of wedge-like elements, one attached to the seal and the other to the housing, which are similar in geometry but positioned in reverse orientation with respect to one another. These form a slidably engaged contact surface inclined at a predetermined angle with respect to the shaft centerline. Positive lubrication is provided between the sliding surfaces by means of fluid supply holes that extend from a region of high pressure within the seal to a slot located inside the sliding face of the wedges.