GB905582A - Improvements relating to the sealing of blades in a bladed rotor - Google Patents

Abstract

905,582. Bladed turbine rotors. ROLLS-ROYCE Ltd. May 24, 1961 [May 26, 1960], No. 18724/60. Class 110 (3). A rotor such as the turbine rotor of a gas turbine engine has a plurality of blades the roots of which are mounted in angularly spaced apart slots in the rotor, an annular assembly of sealing plates being provided, the sealing plates having surfaces which engage adjacent end surfaces on the rotor and on the roots, means being provided to retain the sealing plates in the engaged position, the sealing of the roots to the rotor being effective solely by the fact that all of the surfaces are made substantially perfectly flat. The rotor disc 10 is formed with axially-extending slots 11 in which the roots 12 of the blades 14 engage. Sealing plates 22, 23 are received in grooves 17 formed in the lower surfaces of the blade platforms 15 and in grooves 21 formed in the radially outer surface of a flange 18 at one side of the rotor disc. The flange 18 is cut away at one point to provide a gap 33 having sides 34, 35. To assemble, all the blades 14 are entered into their slots 11 with the exception of three adjacent the gap 33. All the larger plates 23 are then introduced through the gap 33 into the grooves 17, 21, and the last three blades are then inserted. One of the small plates 22 is then inserted through the gap 33 into the grooves 17, 21 and the plates are then moved circumferentially until the small plate 22 is diametrically opposite the gap 33. A second small plate 22 is then inserted into the gap 33 and entered in the grooves 17, 21. The plates are then again moved circumferentially until the small plates are on opposite sides of the gap and about 90 degrees therefrom. A locking plate 36 having tabs 38 is then welded on the plate 23 which is adjacent the gap 33, the tabs 38 engaging the sides 34, 35 of the gap to prevent circumferential movement of the sealing plates. The locking plate 36 could be secured to a sealing plate before assembly, the tabs 38 being bent so as to clear the flange 18, but being subsequently bent down to engage the sides of the gap. The sealing plates serve to prevent cooling air flowing through the spaces between the blade stems. Sealing plates may be disposed at both faces of the rotor disc and blade roots. In a second embodiment, no gap is provided in the flange 18, but instead four of the blade platforms 47 are cut away at each side as indicated at 50 in Fig. 8. All the blades are assembled on the rotor with the exception of the four with cut-away platforms. Sealing plates 23 are then engaged with the grooves 21 in the rotor and the grooves 17 in the blade platforms, at both sides of the rotor disc. The four blades are then entered in their slots and the final sealing plates 51, one at each side are entered by inserting the lower ends in the grooves 21 and then pivoting the plates so that projections 52 at the outer edges of the plates engage in the cut-away portions 50 of the blade platforms 47. The sealing plates are then moved circumferentially so that the projections 52 engage in the grooves formed in the uncutaway portions of the platforms 47. The tabs 54 of the locking plates 53 are then bent to engage the cut-away portions 50 of the blade platforms 47 so securing the plates against circumferential movement.