Abstract: A seal for sealing between a hollow outer shaft and an inner shaft concentric with the outer shaft has a seal ring with a plurality of segments extending around the inner shaft. The seal ring has an outer circumferential face confronting the inner surface of the outer shaft, a first side face exposed to a region of high pressure and a second side face confronting a mating ring secured to the inner shaft and having a portion thereof exposed to a region of lower pressure. A segmented compensating ring extends around the inner shaft and spaced from the seal ring in the region of high pressure. A flange secured to the inner shaft limits the axial movement of the compensating ring away from the seal ring. A continuous balancing ring between the seal ring and the compensating ring has a pair of conical faces mating with conical faces on the seal ring and compensating ring, respectively. Advantageously, hydrodynamic and closed pockets in the bearing surfaces are used to vary the contact forces.

Abstract: A pair of balancing weights are mounted on opposite sides of the center line of the rotor for movement about the axis of the rotor. The weights are automatically locked against movement about the axis of the rotor when the rotor is rotating below critical speed and automatically released for free movement about the axis of the rotor when the rotor is rotating above critical speed. The weights are exemplified as roller cages. The balancing weights are variously locked by mechanical clutches actuated at critical speed. The clutching for the weights is either individual or such that the weights are necessarily locked against movement and released simultaneously. Centrifugal force is used to control the clutches.

Abstract: A seal for sealing between a rotating member and a housing comprises a seal ring mounted for movement towards and away from the rotating member and having a high pressure side, a low pressure side, and a face opposed to the rotating member. Resilient means urge the seal ring towards the rotating member. Hydrodynamic means in the form of a plurality of spaced recesses in that face of the seal ring opposed to the rotating member, with the entry to each recess more restricted than its exit so as to produce negative hydrodynamic lift in the recess and urge the seal ring towards the rotating member. A seal is provided between the housing and the seal ring.