Patent GB-819814-A (GB)
Title: Improvements in or relating to axial-flow fluid machines, for example axial-flow compressors
Inventor: PAYNE NIGEL EDWARD
IPC: F01D9/06
Filed: 1956-05-10
Abstract: 819,814. Axial-flow compressors and turbines. ROLLS-ROYCE Ltd. May 7, 1057 [May 10, 1956], No. 14644/56. Classes 110 (1) and 110 (3). The invention relates to a stator blade assembly for supporting a bearing of the rotor of an axial-flow compressor or turbine comprising a ring of blades 23 most of which are of solid forged construction, each solid forged blade having a root platform 23b at its radially inner end and a tip platform 23c at its radially outer end. The invention is described with reference to the inlet end of an axial-flow compressor comprising inlet guide vanes 12, a first stage of rotor blades 16 mounted on a disc 17 which is carried on a stub shaft 18 at the upstream end of the rotor 19, the rotor carrying a disc 22 on which is mounted a second stage of rotor blades 21. A row of first-stage stator blades 23 is disposed between the rotor blades 16 and 21 and the bearing 20 in which the stub shaft 18 is mounted is supported by means of the stator blades 23. The root platforms 23b of the blades 23 are circumferentially narrow and are mounted in slots in a ring member 24 which is provided with inwardly-extending flanges 24a, 24b, axially-extending flanges 24c extending from the flanges 24a, 24b. An annular bearing support member 27 is formed with a pair of divergent flanges 27a, 27b, the outward portions of which are formed with axially-extending flanges which engage within the flanges 24c. Channel-section members 25, 26 are disposed at the upstream and downstream sides of the ring member 24, the parts 24, 25, 26, 27 being secured together by welding at 30 and the blades 23 being brazed in the slots in the ring 24. A sleeve 20b is secured within the bearing support member 27 and engages by means of a spline connection the outer race 20a of the bearing 20. The member 27 also carries two labyrinth seal members 28 which have axial flanges at their inner peripheries which co-operate with ribs formed on the stub shaft 18. The tip platforms 23c of the blades 23 are formed with axial flanges 23d, the upstream flanges engaging a circumferential groove in the shroud ring 14 which is supported by means of a radial bolting flange 14a from the outer casing 10, 15, and the downstream flanges 23d engage a circumferential groove formed in the shroud member 31 which is supported from the outer casing 15 by means of studs 32. The circumferentially-spaced edges of the tip platforms 23c are formed with upstanding ribs 23e, the ribs of adjacent blades abutting one another and being secured together by welding at 33. Some hollow blades 23a may be provided in place of solid forged blades and these comprise an outer sheet-metal portion 34 of aerofoil shape and an inner portion 35 of flattened tubular shape, the radially inner end of the outer portion being formed with lateral flanges 36 of circular arcuate shape, the flanges engaging a circular hole 37 formed in the ring 24. The radially outer end of the outer portion 34 is brazed in a correspondingly-shaped slot in a plate 38 which extends between the outer platforms 23c of the forged blades on each side of it, the plate 38 being formed with axial flanges 38a corresponding to the flanges 23d of the platforms 23c. The inner portion 35 of the hollow blade extends at each end beyond the outer portion 34, the end portions being of circular cross-section, the outer end portion being connected to a socket 42 of an elbow connection 43, and the inner end portion engaging a socket 41 formed in a boss on the external surface of the bearing support member 27. The hollow blades may be utilized for supply and discharge of lubricating oil and for passage of instrument lines. A lug member is secured to the plate 38 and has an end portion which engages a notch formed in the grooved upstream edge of the shroud ring 14, thereby locating the stator blade assembly circumferentially within the casing.