Patent ID: 8322990

Claim:
A vibration damper for use in a turbomachine having at least one turbine rotor, the at least one turbine rotor having a plurality of radially extending blades, each blade including an aerofoil, a platform located radially inwardly of the aerofoil, and a stem located radially inwardly of the platform, the vibration damper comprising: a seal-region comprising a pair of sealing surfaces configured for engagement with respective contact surfaces provided on adjacent blade platforms; and a mass-region configured to extend radially inwardly from the seal-region and to terminate at a position located between adjacent blade stems, wherein the seal-region is shaped such that: i) a first one of the pair of sealing surfaces lies in a substantially radial plane relative to the rotor, for engagement with a radial contact surface on one of the adjacent blade platforms, and ii) said sealing surfaces converge in a radially outward direction relative to the rotor, for engagement with similarly converging contact surfaces on the adjacent blade platforms, the platform of each rotor blade comprises a projection located substantially radially inwardly of a second contact surface to define a recess between the second contact surface and the projection, the seal-region defines a stepped region, a portion of the seal-region and the stepped region is positioned within the recess, the mass-region is shaped such that the mass-region has a greater mass on a side of the damper having the stepped region than on an adjacent side of the mass-region away from the stepped region, and the side of the mass-region having a greater mass is positioned radially below the recess.