GB623557A - Improvements in or related to turbine discs, rotors, and blades - Google Patents

Abstract

623,557. Turbine and compressor rotors. ATKINSON, J. May 28, 1946, No. 16134. [Class 110(iii)] The rotor has a peripheral V-shaped groove, the sides of which are circumferentially serrated to receive corresponding serrations on the blade roots; after insertion, the blades are twisted about their longitudinal axes to bring their roots into locking engagement with the groove. The blade roots 9 are of substantially parallelogrammic section and the serrations 7 are preferably of substantially " buttress " form. The additional space required for the insertion of the last blade is afterwards taken up by spacing all the blades at equal intervals. The spaces between blades may be closed by peering over the metal at each side of the top of the root, leaving a central gap for the passage of cooling air. Alternatively, locking screws may be inserted into radially disposed threaded holes formed partly in adjoining blades. In a further alternative, each blade root is provided with a substantially semicircular recess 12 of semi-circular crosssection, a wire being forced into the mating recesses of adjacent roots. The wires may be cut to different lengths as necessary for balancing the rotor. Cooling air may be supplied through holes 13, or it may be fed to spaces between blade roots by way of radial holes in the roots communicating with the bore of a hollow rotor shaft. The rotor rim may be slotted radially at intervals between the blades to reduce stresses due to thermal expansion. Vanes for inducing a flow of cooling air over the outer faces of the rotor may be carried by or formed integral with one or both faces. According to the Provisional Specification, the rotor disc may be formed in two halves which are clamped together to hold the blades, and the serrated groove may have parallel sides. The blade roots may carry interlocking serrations.