Pratt & Whitney Aircraft of Canada Ltd.

Pratt-whitney Canada Corp

Ivor J Roberts

A carbon seal assembly comprises an annular member adapted to be secured to a structure. An annular seal runner is sealingly mounted to a shaft to rotate therewith, with the seal runner being made of a material complementary to that of the annular member for magnetic attraction therebetween. An annular carbon seal element is mounted to the annular seal runner to rotate therewith and positioned in a gap between the annular member and the annular seal runner, the annular carbon seal element having an annular wear surface abutting against a face of the annular member. A cross-sectional area of the annular carbon seal element increases as the axial dimension of the annular seal runner decreases for at least a part of the seal.

Carbon seal assembly

An improved bleed valve for the compressor of a gas turbine engine comprises a port communicating with the intermediate section of the compressor. An annular valve seat surrounds the port, the valve seat having a radial surface terminating in an outer peripheral circular rim. A piston is provided having a flat radial surface and adapted to close on the valve seat, the piston having a peripheral inner cylindrical surface having a diameter corresponding to the outer circular rim of the valve seat. The axial component of the piston inner peripheral surface is chosen such as to be sufficient to close the so-formed nozzle just prior to the piston radial surface closing on the valve seat to prevent chattering of the piston caused by diffuser effect.

Bleed valve

A rotor assembly including a spool and a plurality of radially extending rotor blades mounted in a groove provided circumferentially of the spool is described. The groove includes a pair of inwardly extending flanges which define a throat area narrower than the groove. A stacking hole extends radially and communicates with the groove to allow the rotor blade members to be individually mounted to the spool. The locking device for retaining the rotor blades in the spool includes a C-shaped spring adapted to urge against the roots of each rotor blade in the groove and a locking protrusion adapted to engage in the stacking hole and in an opening formed in the platforms of two adjacent blades straddling the stacking hole whereby the locking device abuts against the ends of the flanges in the stacking hole and retains the rotor blades against circumferential movement. A pair of anchor members can also be provided near the ends of the C-shaped spring member for engagement in the root of pairs of blades.

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St. Lambert, Canada

Ivor J Roberts