GB806033A - Improvements in or relating to fluid machines having bladed rotors - Google Patents

Abstract

806,033. Elastic-fluid turbines; axial-flow compressors. ROLLS-ROYCE Ltd. Aug. 24, 1956 [Sept. 26, 1955], No. 27414/55. Class 110 (3). In a bladed rotor for an axial flow turbine or compressor, of the type in which a ring of blades is mounted on the periphery of the rotor disc by means of blade roots having outwardlyextending portions defining a series of axiallyextending spaces radially inwards of the working fluid passage, the blades have fluid-flow passage means therein, at least one end of the passage means in each blade opening to one of the axially-extending spaces between its root and the roots of the adjacent blades, and an annular plate is mounted on the rotor disc in spaced relation to the disc periphery to define an annular manifold which communicates with the passage means and defines with the disc a path for the supply of fluid to the manifold from a point at lesser radius than the manifold. In the turbine rotor shown in Figs. 1 and 2, an annular plate 29 is secured to the rotor disc 10 by bolts 33, 38 engaging captive nuts 34, 39 in projections 35, 40. A flange 41 on the plate 29, sealed relative to a stator part 43 by a labyrinth seal 42, affords a chamber 44 from which high-pressure air flows outwardly past the projections 35, 40 into a manifold formed between the plate 29 and a further annular plate 24. The air then passes through holes 26 in the plate 24 and registering ports 22 in the blade root stems 15 to passages 18, 19 in each blade 11, through which it flows upwardly to a cross-passage 21 and then downwardly through a passage 20 to a port 23 in one of the circumferentially-facing surfaces of the corresponding stem 15, thereby cooling the blade. The air then escapes from the spaces between the stems 15, either through circumferential gaps between blade platforms 14 or through exit passages provided in a plate 17. After the cross-passage 21 has been milled in the blade tip shroud 12, the shroud is closed by a plate 46 which slides into a dovetail groove in the shroud and is tackwelded in position. The blades 11 are located axially by the plate 17 and by tangs 16 which bear against the disc 10. The plate 24 has slots 27 which fit over the tangs 16, and tongues 28 and a flange 25 which hold the plate 29 away from the plate 24. A bead 30 on the plate 29 fits outside the flange 25 and behind flanges 31 on the platforms 14. In the embodiment shown in Figs. 5 and 6, the cooling air enters blade passages 57, 58 of each blade 51 from the axially-extending space 56 at one side of the blade root stem 55, and flows out of blade passage 59 into the space 56 at the other side of the stem 55. Passages 57, 58 open to alternate spaces 56, and passages 59 open to the remaining spaces 56. The cooling air enters the alternate spaces 56 by way of holes 66 in an annular plate 64 from the space 90 between the plate 64 and another annular plate 70. The air flows to the space 90 from a duct 88, by way of a chamber 86 and a space 89. Plate 70 bears against circumferentially-spaced projections 75 on the rotor disc 50, with circumferentially-spaced projections 81 engaging behind projections 82. Dowel pins 76 pass through the plate 70, each pin engaging between a pair of projections 75. A tongue 77 on each pin 76 projects into a notch in a bead 79 on the plate 70, and a spring-retaining ring 80 holds the pins in place. The blades 51 are located axially by an annular plate 63 and by pairs of tangs 62 which bear against the disc 50. Tongues 67 project from the plate 64 between each pair of tangs 62, with projecting ribs 69. Specification 802,476 is referred to in the Provisional Specification.