Abstract: An apparatus has: a first member; a shaft rotatable relative to the first member about an axis; and a seal system. The seal system has: a seal carried by the first member and having a seal face; a seal housing; a seat carried by the shaft and having a seat face in sliding sealing engagement with the seal face; and a plurality of coil springs biasing the seal face against the seat face, each coil spring having a first end and a second end. The seal has a plurality of spring compartments. Each of the plurality of coil springs is partially within a respective associated compartment of the plurality of spring compartments.

Abstract: A turbomachine has a bearing in a bearing compartment. A first seal system isolates the bearing compartment and has: a first runner; a second runner; an inner seal encircling the first runner; and an outer seal encircling the second runner. The inner seal has a static clearance with the first runner. The outer seal has a static clearance with the second runner, greater than the inner seal static clearance. The first runner has an inner portion cantilevered inward. The second runner has an outer portion cantilevered outward.

Abstract: A seal assembly includes a carbon seal that has a sealing surface. A seal seat has a sealing surface and is positioned for rotation relative to the carbon seal. A diamond-like carbon coating at least partially forms the sealing surface on the seal seat.

Abstract: A seal assembly includes a housing that includes a seal flange at least partially defining a seal opening. A carbon seal is located at least partially in the seal opening and includes a first axially facing surface. The seal flange includes an axially facing surface that has a carbide based coating and a diamond-like carbon coating in engagement with the first axially facing surface on the carbon seal.

Abstract: A turbomachine has a bearing in a bearing compartment. A first seal system isolates the bearing compartment and has: a first runner; a second runner; an inner seal encircling the first runner; and an outer seal encircling the second runner. The inner seal has a static clearance with the first runner. The outer seal has a static clearance with the second runner, greater than the inner seal static clearance. The first runner has an inner portion cantilevered inward. The second runner has an outer portion cantilevered outward.

Abstract: A seal assembly includes a housing that includes a seal flange at least partially defining a seal opening. A carbon seal is located at least partially in the seal opening and includes a first axially facing surface. The seal flange includes an axially facing surface that has a carbide based coating and a diamond-like carbon coating in engagement with the first axially facing surface on the carbon seal.

Abstract: A seal assembly includes a carbon seal that has a sealing surface. A seal seat has a sealing surface and is positioned for rotation relative to the carbon seal. A diamond-like carbon coating at least partially forms the sealing surface on the seal seat.

Abstract: A seal assembly includes a housing at least partially defining a seal opening and at least partially surrounding a rotatable shaft. A carbon seal is located at least partially in the seal opening and includes a sealing surface. The rotatable shaft includes a radially facing surface that has a carbide based coating and a diamond-like carbon coating in engagement with the sealing surface on the carbon seal.

Abstract: An assembly includes a housing, a carrier, a spring element and a seal element. The housing includes a bore and an annular groove that extends axially along a centerline into the housing from the bore. The carrier projects axially along the centerline into the annular groove. The carrier is configured to translate axially along the centerline relative to the housing. The spring element is arranged within the annular groove. The spring element is configured to bias the carrier axially away from the housing along the centerline. The seal element is mounted to the carrier and arranged within the bore.

Abstract: A turbomachine has a bearing in a bearing compartment. A first seal system isolates the bearing compartment and has: a first runner; a second runner; an inner seal encircling the first runner; and an outer seal encircling the second runner. The inner seal has a static clearance with the first runner. The outer seal has a static clearance with the second runner, greater than the inner seal static clearance. The first runner has an inner portion cantilevered inward. The second runner has an outer portion cantilevered outward.

Abstract: An apparatus has: a first member; a shaft rotatable relative to the first member about an axis; and a seal system. The seal system has: a seal carried by the first member and having a seal face; a seal housing; a seat carried by the shaft and having a seat face in sliding sealing engagement with the seal face; and a plurality of coil springs biasing the seal face against the seat face, each coil spring having a first end and a second end. The seal has a plurality of spring compartments. Each of the plurality of coil springs is partially within a respective associated compartment of the plurality of spring compartments.

Abstract: Apparatus and associated methods relate to a segmented radial seal assembly that includes at least two segments, each segment having a first end and a second end at opposite ends. A first segment first end has a protruding feature and defines a tangential vector from a circumferential ring that is formed by the segmented radial seal. The protruding feature defines a curved face having at least a first axis of curvature that is parallel to the tangential vector. The second segment second end has a recessed feature that is matingly engageable to the first segment first end, thereby forming a first radial seal segment joint. The segmented radial seal assembly is configured to surround a shaft.

Abstract: A face seal arrangement includes a seal seat rotating with the shaft and a non-rotating face seal including a sealing ring. The sealing ring includes a sealing face biased into contact with the seal seat. The sealing ring also has a groove defined remote from the seal face relative to the seal seat. The groove provides a pressure face that will be exposed to high pressure air outward of the bearing compartment. A coil spring biases the seal housing towards the seal seat, such that the sealing face of the sealing ring is biased into contact with seal seat by air pressure against the pressure face, and the coil spring. A balance ratio is defined between an area of the pressure face and an area of the sealing face, the balance ratio is between 0.5 and 0.64.

Abstract: A turbomachine has a bearing in a bearing compartment. A first seal system isolates the bearing compartment and has: a first runner; a second runner; an inner seal encircling the first runner; and an outer seal encircling the second runner. The inner seal has a static clearance with the first runner. The outer seal has a static clearance with the second runner, greater than the inner seal static clearance. The first runner has an inner portion cantilevered inward. The second runner has an outer portion cantilevered outward.

Abstract: A seal housing may comprise an aft flange, an outer diameter (OD) ring and a stopper. The stopper may extend radially inward from a radially inner surface of OD ring. The stopper may be configured to interface with a monobloc carbon seal. The stopper may comprise a circumferential stopping portion and an axial stopping portion. There may be a plurality of the stopper.

Abstract: A method of determining wear of a seal element includes rotating a seal plate relative to the seal element and such that the seal plate and the seal element form a rotational sealing interface. The seal element includes an insert embedded in the seal element. A portion of the seal element is worn with a sealing face of the seal plate. The insert is contacted with the sealing face of the seal plate. A portion of the insert is worn to create a wear particle of the insert. The presence of the wear particle in a lubrication oil is sensed with an oil monitoring system.

Abstract: A face seal arrangement includes a seal seat rotating with the shaft and a non-rotating face seal including a sealing ring. The sealing ring includes a sealing face biased into contact with the seal seat. The sealing ring also has a groove defined remote from the seal face relative to the seal seat. The groove provides a pressure face that will be exposed to high pressure air outward of the bearing compartment. A coil spring biases the seal housing towards the seal seat, such that the sealing face of the sealing ring is biased into contact with seal seat by air pressure against the pressure face, and the coil spring. A balance ratio is defined between an area of the pressure face and an area of the sealing face, the balance ratio is between 0.5 and 0.64.

Abstract: A seal assembly includes a housing that includes a seal flange at least partially defining a seal opening. A carbon seal is located at least partially in the seal opening and includes a first axially facing surface. The seal flange includes an axially facing surface that has a carbide based coating and a diamond-like carbon coating in engagement with the first axially facing surface on the carbon seal.

Abstract: A seal assembly includes a housing at least partially defining a seal opening and at least partially surrounding a rotatable shaft. A carbon seal is located at least partially in the seal opening and includes a sealing surface. The rotatable shaft includes a radially facing surface that has a carbide based coating and a diamond-like carbon coating in engagement with the sealing surface on the carbon seal.

Abstract: A seal assembly includes a carbon seal that has a sealing surface. A seal seat has a sealing surface and is positioned for rotation relative to the carbon seal. A diamond-like carbon coating at least partially forms the sealing surface on the seal seat.