GB803137A - Improvements in or relating to axial-flow fluid machines for example turbines and compressors of gas-turbine engines - Google Patents

Abstract

803,137. Turbine and compressor stator vane assembly. ROLLS-ROYCE, Ltd. July 17, 1956 [Aug. 5, 1955], No. 22682/55. Class 110 (3). In an axial-flow fluid machine such as a turbine or compressor of a gas turbine engine, a stator assembly comprises a ring of hollow stator guide vanes which are secured at their ends in hollow, box-like inner and outer platform structures, the passages within the hollow guide vanes opening into the interiors of the box-like structures. The guide vanes are mounted in an outer casing by means of the outer platform structures and ducts are provided connecting the interiors of the outer platform structures to the exterior of the outer casing, and connecting the interiors of the inner platform structures to a chamber within the internal stationary structure of the machine. The gas turbine shown comprises a rotor disc 11 mounted at the end of a shaft 10 which rotates in a bearing 16. Gases from combustion equipment 15 are directed by inlet nozzle guide vanes 14 on to the rotor blades 12. The guide vanes 14 are hollow and they are arranged in groups of three, the outer ends of the vanes of each group being entered in slots in the inner wall 17 of an outer platform structure. The outer walls 18 of the outer platform structures have flanges 18a therearound, the flanges being connected to the inner walls 17. Each outer wall 18 is formed with a hollow boss 20 which is connected to a hollow boss 22 on the outer casing 13 by means of a tubular plug 21. The outer wall 18 is also formed with dogs 24 which engage dogs 25 formed on the inner surface of the outer casing 13 so as to locate the outer platform structure circumferentially. A shroud ring 27 for the rotor blades 12 engages a groove in the downstream edge of the wall 18 and is located axially and circumferentially with respect to the outer casing 13, the shroud ring thus locating the outer platform structure in an axial direction. The inner platform structures each comprise an outer wall 28, in which the inner end of the three vanes 14 are mounted, and an inner wall 29 having flanges 29a, the walls being connected together to form a boxlike structure. The inner walls 29 are each formed with a hollow boss 31 which engages a boss 35 on a ring member 34, and with an axial flange 46 which engages in a recess in a clamping ring 38. The outer walls 28 are each formed with an axial flange 44 which engages in a recess in a second clamping ring 37. Diaphragm members 32, 33 are secured between the clamping rings 37, 38 and the ring member 34, the parts being secured together by bolts. The diaphragm members 32, 33 have axiallydirected flanges 39, 40 which abut so as to hold the diaphragms in axially spaced relation. The annular chamber 47 formed by the diaphragms 32, 33, flanges 39, 40 and ring member 34 receives low pressure air through holes 51 in the diaphragm 32 or through holes 52 in the hollow shaft 10, air flowing through the holes 52 flowing through rotating seal 55 and holes 54 into the chamber. Air from the chamber 47 flows into the interiors of the inner platform structures, through the hollow vanes 14 to the interiors of the outer platform structures and thence to atmosphere. Instead of the arrangement shown, the outer platform structures may each constitute an outlet chamber from one hollow guide vane only.