GB875412A - Improvements in or relating to axial flow turbines or compressors - Google Patents

Abstract

875,412. Turbine blade fixings. BRISTOL SIDDELEY ENGINES Ltd. May 30, 1960 [May 30, 1959], No. 18514/59. Class 110 (3). The invention relates to axial flow turbines or compressors of the kind in which the rotor disc 12 or blade supporting member of the stator has undercut circumferentially extending serrations 13 arranged to co-operate with complementary undercut serrations in the roots of blades A, B, C carried thereby, the serrations in the rotor disc or stator member being interrupted by a radially extending gap 14 forming a gate providing radial access for the blades to and from the circumferentially extending serrations. There are three types of blades A, B, C provided. The blades A are positioned in abutment with one another around most of the periphery of the rotor and the blades B, C are arranged in pairs around the remainder of the periphery in the vicinity of the gate. The circumferential width of the gate 14 is smaller than the circumferential width of each blade root and the serrations of each root are relieved at 16, 17 to enable the blade to be inserted or removed radially through the gate 14. The roots of the blades A, C are of the same circumferential width and those of the blades B of thinner circumferential width. This enables the blades to be moved along the serrations so as to leave sufficient room for the insertion or removal of the last blades C10, Fig. 4, through the gate. The circumferential spaces between the blades B9, C10, after the insertion of the last blade, is reduced by spacing the blades around the disc between the blades A0, A11 and inserting U-shaped spacers 18, 18<SP>1</SP>. The circumferential width of a spacer is such that together with a blade root B it equals the circumferential width of a blade A or C. The inner edges of the limbs of the U are arranged to embrace the serrations 13 so that the spacers are located axially but are not undercut so that the spacers may be withdrawn or inserted radially without having to be moved to the gate 14. Axially extending slots 19, 19<SP>1</SP> cut in the periphery rotor are engaged by the spacers to prevent circumferential movement of the spacers. The spacers 18, 18<SP>1</SP> are prevented from moving radially outwards by locking members 21 of substantially T-section. The cross limbs of each T engage slots 22, 23 in the adjacent faces of the spaced roots B and C. One of the blade roots adjacent each locking member 21 has a depression 24 into which the thinned section 25 of each locking member may be deformed to prevent axial movement of the locking member.