GB729665A - Hollow blades for turbines and axial flow compressors - Google Patents

Abstract

729,665. turbine and compressor, blades. NAPIER & SON, Ltd., D. Sept. 11, 1953 [Sept. 12, 1952], No. 22999/52. Class 110 (3). A blade for the rotor or stator of a turbine or axial-flow compressor comprises a blade portion formed from sheet-metal manipulated into a hollow aerofoil section.and a root portion made in two parts having internal recesses which respectively receive formations on the ends of the sheet-metal flanks of the blade portion, and the front and rear edges of the formations abut and are exposed and are secured together and to adjacent exposed areas of the said two parts. In the turbine rotor blade shown, the blade portion 10, Figs. 1 and 2, is made from sheetmetal, for instance a nickel chrome steel, folded at the leading edge 11 into a hollow aerofoil form. The Outer end 13 of the concave flank 14 is bent over to meet the outer end of the convex flank 15. A comb-like spacer 16, Fig. 7, is inserted between the flanks at the trailing edge 12. The flanks may be thinned down towards the trailing edge. The inner ends 19, 20, Fig. 2, are manipulated into a formation of approximately elliptical section, and are received in corresponding recesses in the two parts 22, 23 of the Made root portion with their abutting edges exposed between the parts 22, 23 as shown at 29. The inner ends 19; 20 may be brazed to the recesses. The parts 22, 23 and the exposed edges of the inner ends 19, 20 are welded together and the welding is continued up the trailing edge 12 after the spacer 16 has been cut flush with the trailing edge. The outer ends are also welded together. In use, coolant is introduced, as from an open-sided annular gallery in a fixed part of the turbine adjacent the rotor, through a passage 26 and flows outwardly through the hollow blade in front of an inner baffle, over the end of the baffle and down behind it, and thence through the apertures between the teeth of the spacer 16. In place of the baffle, or in addition to it, a small hole may be formed in the outer end 13 near the leading edge 11, to prevent accumulation of coolant adjacent the outer part of the leading edge. The two flanks of the blade may be made of separate pieces of sheet-metal.