GB737472A - Turbines and like machines having adjustable guide blades - Google Patents

Abstract

737,472. Turbines ;axial-flow compressors. NAPIER & SON, Ltd., D. Sept. 28, 1953 [Oct. 3, 1952], No. 24894/52. Classes 110 (1) and 110 (3). In a turbine or compressor having a ring of guide blades adjustable about radial axes and lever arms each attached by one end to one of the adjustable blades, the other ends of the arms being connected to a common annular adjusting member so as to permit relative radial movement between the levers and the adjusting member, the adjusting movement of which is in the axial direction, the dimensions of the adjusting member are such that it is substantially more rigid in the axial than in the radial direction and is actuated by several similar servomotors disposed at intervals around it. The hot gases from an annular combustion chamber or several individual combustion chambers 11 pass through a ring of adjustable guide blades 12 to the turbine rotor blades 13. The combustion chambers 11 have a sliding fit in an annular member 16. The blades 12 are supported at their inner ends in the flange 19 of the annular member 16 by pivot spigots 24 and at their outer ends by pivot spigots 25 which turn in bearings 26 carried by the outer casing 27. Each of the spigots 24 has a lever arm 28 secured to its innermost end. The lever arms 28 which lie approximately in the circumferential direction when the blades 12 are set in the central position carry pins 30 which engage circumferential slots in an annular adjusting member 31 so that relative movement between the pins 30 and 31 is permitted in the radial and circumferential directions, but not in the axial direction. The adjusting member 31 comprises a hoop whose width a is substantially greater than its radial thickness b. Projections 32 on its rear edge are connected to the pistons 33 of servomotors 34 controlled by fluid supplied through pipes 35, 36 by a control valve. To avoid all of the axial thrust on the blades 12 being taken through the outer ends of the blades, compressed air from the compressor is led through the shaft 15 and ports 22, 23 to the rear of the annular member 16. The ring of blades 12 may include some fixed blades as described in Specification 737,473. The adjusting member 31 may be arranged outside the ring of guide blades instead of, as shown, inside this ring.