Patent GB-705150-A (GB)
Title: Improvements in and relating to variable guide blade arrangements for high temperature turbines
IPC: F01D25/12
Filed: 1952-10-10
Abstract: 705,150. Elastic-fluid turbines. GENERAL ELECTRIC CO. Oct. 10, 1952 [Oct. 10, 1951], No. 25447/52. Class 110 (3) A variable guide blade arrangement for an axial-flow turbine comprises inner and outer casing members, circumferentially spaced, radially extending, rotatably adjustable control rods 36 which are supported in one casing member and carry the guide blades 35, arcuate segments 71 loosely supported from the other casing member to define therewith a pressure chamber 77 and to define one wall of the fluid flow path, interengaging spherical surfaces on the segments and the blades and means to supply pressure fluid to said chamber to urge the segments into engagement with the blades. The casing comprises an outer member 3a which is formed in two or more parts bolted together and inner members 3b, 3c, the members 3a, 3b being connected by studs 4 and the members 3b, 3c being secured together by screws 17. The vanes co-operate with inner and outer walls made up from segments 68, 71 respectively. There are two vanes for each cooperating pair of segments, the segments 71 being interlocked as shown in Fig. 7 (not shown). The rods 36 are actuated by a control ring 59 which is supported by rollers 60, 61 and acts through links 57. The rollers are supported in a ring 63 spot welded to a member 64 which is seated on projections 65 formed integral with the casing 3a. The control ring 59 comprises at least two arcuate segments interconnected by a bolted flange connection 66, 67 and is actuated by an elecric or hydraulic motor. Cooling air is fed through the studs 4 into a chamber 21 and discharged through ports 21c, 21d against the rotor discs as shown, at least one tapping 78 communicating with the chamber 77. The chamber 21, comprises a plate 21a welded to a plate 21b which in turn is spot welded to the member 3b. The members 68, 35 and 71 are also urged together by leaf springs, each segment and its associated leaf spring being held in position by a dowel. The segments 71 are also urged towards the right by further leaf springs which bear against a flange 76 of the member 3c. Part of the fluid flow path is defined by segmental wall portions 6a, 7a, the segments 6a having axially spaced tongues 8 9 which extend only over a part of the circumference of the casing. Shrouds 18 are loosely mounted between the segments 6a, 7a or welded to one of the segments, each shroud having an end plate 19 welded thereto. Each rod 36 is welded to its blade at 39 and journalled in a water cooled bushing 37. The supply and drain conduits 40, 48 of the bushings are interconnected by circumferentially extending manifolds which may constitute external pipes or passages formed in the member 3a. The blades 38 may be cast, forged, machined from bars or fabricated from sheet metal. Sheet metal radiation shields 13, 14, 15 are provided as shown. Members 6a, 68, 7a and 71 are made of austenitic steel and the member 3c is made of ferritic steel. Sealing means 29, 30, 32, 33, 49, 50 and 51 are provided as shown.