GB837556A - A blade assembly for axial flow compressor, turbine or blower and method of making the same - Google Patents

Abstract

837,556. Axial-flow turbines and compressors. LATHAM, N. R. July 10, 1956 [July 12, 1955], No. 21380/56. Classes 110 (1) and 110 (3). [Also in Group XXII] A blade assembly for an axial-flow compressor, turbine or blower comprises an individual supporting ring for each row of blades and spacer rings secured in axial aligmnent between adjacent blade supporting rings and formed with annular projections partially overlapping the blade support rings. Each blade supporting ring is formed with a plurality of circumferentiallyspaced slots across the peripheral face thereof, each slot being of such a depth as to extend into the portion of the ring underlying the annular projections of the adjacent spacer rings, the blades having root portions filling the slots so that the blades are retained in position radially by the projections. The invention is shown applied to an axial-flow compressor comprising a stator casing 16 and a rotor 18. The stator comprises a pair of end rings 12, 14 between which are disposed blade-carrying rings 20 and intermediate spacer rings 22, the assembly being held together by longitudinally-extending tie-bolts 37. The rotor likewise consists of a pair of end members 56, blade-carrying rings 40 and spacer rings 50, the assembly being held together by tie-bolts 58. Stub shafts 66 secured within the members 56 are rotatably supported in the stator end rings 12, 14 by means of bearings 68. A driving pulley 74 is secured on one of the stub shafts. Air enters through inlets 76 to the annular passage 78 and is delivered from the annular passage 80 through the outlet 82. The rotor bladecarrying rings 40 are of T-section, as shown in Figs. 5 and 6, having annular grooves 42 on their outer surfaces. They are also formed with circumferentially-spaced blade receiving slots 44 the depth of which is greater than that of the annular grooves 42. Blades in the form of curved plates 46 are mounted in the slots 44 the leading and trailing edges of the blades then being machined away so that the root end of each blade is of T-shape with the projections of the T disposed in the slot 44 inwardly of the annular grooves 42. The spacer rings 50 are also of T-section, the projections of the T engaging in the annular grooves 42 whereby the blades are held securely in position. Packing rings 54 are disposed between the bladecarrying and spacer rings. The stator blades 30 are formed and mounted in a similar manner. The radial width of the working fluid annulus is uniform from inlet to outlet and the number of blades in each circumferential row is the same, but the angular setting and curvature of the blades in each row varies from the inlet end to the outlet end. The curved plates constituting the blades are all of the same curvature, the plates being deformed to the correct curvature when entered in the curved slots 44.