GB643212A - Improvements in and relating to a method or process for fixing turbine blades or thelike to discs or wheels - Google Patents

Abstract

643,212. Elastic-fluid turbines. BRUSH ELECTRICAL ENGINEERING CO., Ltd. April 10, 1947, No. 9498. [Class 110(iii)] [Also in Group XXII] A rotor for a turbine or the like comprises a disc, a peripheral ring on it having a peripheral groove in its interior and pierced with holes having the contour of turbine blades, and blades set in the holes. A groove 2, Fig. 5, having a width substantially equal to the width of the blades, is machined in a steel ring 1, and radial holes 3 are drilled. The order of these two steps may be reversed. The holes 3, the radius of which is equal to the radius of curvature of the rear convex face of the blades, are then enlarged to the sectional shape of the blades by broaching in three stages using a three-part broach as shown at a, b, c in Fig. 8. Each broach has a plain face corresponding to the said rear convex face. The turbine blades 6, Fig. 11, are then fitted into the holes 3 and welded to the ring 1 where they protrude into the groove 2. After heat treatment the ring is trued up and a rebate 11 is turned on each side face. The ring is then shrunk on to a disc 12 and secured thereto by welds 17. A peripheral channel 13, oblique holes 14 and, it may be, rebates 15, have previously been formed in the disc. Finally, the whole assembly is heat-treated and trued up. Side faces of the ring and disc may be machined with annular ribs and grooves to form part of a labyrinth packing. In operation, air or other cooling medium enters the hollow blades through the holes 14. The blades may be solid. Specifications 619,107, 625,693 and 643,259 are referred to.