Patent GB-846329-A (GB)
Title: Combustion turbine power units
Inventor: BLYTH JACK VALLIS
IPC: F01D25/30
Filed: 1957-12-12
Abstract: 846,329. Gas turbine plant. NAPIER & SON Ltd., D. Dec. 4, 1958 [Dec. 12, 1957], No. 38685/57. Class 110 (3). In a gas turbine power unit comprising an air compressor, a compressordriving turbine, and a free power turbine downstream of the compressordriving turbine, the power turbine is supported by at least one bearing mounted in a cruciform carrier, the four radially-extending arms of which are connected by links to the turbine casing, the links being rigid in the circumferential direction relative to the turbine casing, but capable of movement in the radial direction. In the power unit shown, the compressordriving turbine is indicated at 15, the free power turbine 16 being disposed downstream thereof. The power turbine disc is formed with a rearwardly-projecting stub shaft 26 which is rotatably supported in a pair of axially-spaced bearings 27, 28, the turbine disc being connected at its forward face to a power transmission shaft 18 by a toothed or splined connection 17. The bearings 26, 28 are mounted in a cylindrical member 30 forming part of a cruciform carrier 29 which also comprises four radially extending arms 31. The arms 31 extend radially across the annular exhaust gas duct 22 formed between the outer wall 24 and the inner tail cone 23, the arms having at their outer ends cylindrical bosses 38 which are received between yokes 39 of A- shaped link members 40 and are secured thereto by pivot pins. The legs of the A-shaped links 40 are formed with flanges 41 which are secured to a flange 42 at the downstream end of the turbine casing 14. The outer ends of the arms are secured by welding to a cylindrical sleeve 45 which is in sealed connection with the turbine casing flange 42 at its forward end, and with a flange 60 on the duct wall 24 at its rearward end. The sleeve 45 is corrugated at 47 at its forward end and cooling air may be supplied through apertures 49 to the annular space 48 between the sleeve and the duct wall. Lubricating oil for the bearings 27, 28 is supplied through a pipe 33 extending through one of the arms 31, the pipe communicating with a channel 34. A cylinder member 35 is secured to the cruciform carrier 29, a balance piston 36 secured to the power turbine 16 being disposed within the cylinder, and air under pressure tapped from the engine compressor being supplied to the space 37 on the downstream side of the piston. A fairing 43 comprising a rearward portion 52 and a forward portion 57 is disposed around each of the arms 31 where it extends across the annular passage 22. Channelsection members 53, 58 are secured within the trailing and leading portions 52, 57 respectively of the fairing 43 so as to form a chamber 54 around each arm 31. The channel 58 is shaped to provide together with the leading portion 57 two grooves 59 which receive the forward edges of the trailing portion 52 of the fairing. The rearward portion 51 of the outer wall 24, the tail cone 23 and the rearward portion 52 including the channel member 53 of each of the fairings 43 together constitute a first removable assembly. The cruciform carrier complete with bearings 27, 28, cylinder 35, sleeve 45 and links 40 constitutes a second removable assembly, while the forward portion 55 of the outer wall 24, the inner wall 56 and the forward portion 57 including the channel member 58 of each of the fairings 43 constitute a third removal assembly.