GB884596A - Improvements in turbine exhaust casing - Google Patents

Abstract

884,596. Gas turbine plants. GENERAL ELECTRIC CO. Dec. 19, 1958 [Dec. 31, 1957], No. 41041/58. Addition to 809,811. Class 110 (3). A gas turbine plant as described in the parent Specification comprising in a common casing an axial flow compressor feeding a combustion chamber supplying combustion gas to a turbine driving the compressor and a useful output turbine positioned downstream of an coaxial with the first turbine and having a curved tailpipe which communicates with the atmosphere through an end opening the axis of which makes an angle of less than 90 degrees with the axis of the casing and is provided with a depression in its wall on the outside curvature which supports a bearing for the turbine output shaft, has an inner hollow shell which extends from inside the casing through the end wall of the depression and supports the power turbine end shaft. The tail pipe assembly 10 includes a free power turbine 22 having a shaft 24 which extends through the rear wall 28 of the tail pipe casing shell 29 to reduction gear-box. The tail pipe 10 is made up of an outer shell 29 and an inner cylindrical shell 30 which is supported from the outer shell by a floor portion 39 of a depression 36 in the tail pipe 10, by a flange 50 and by three struts 54. A frusto-conical housing 55 is mounted and located within the inner cylindrical shell 30 by an integral end wall 57 having a flange 66 which is bolted to a flange 68 of the inner shell. The aft end of the housing 55 is slidably mounted in the inner shell 30 by means of co-operating surfaces 74, 80. The shaft 24 is supported by bearings 82, 84 mounted in the walls 57, 58 respectively. The inner shell 30 also supports a baffle disc 98. Compressed air from the engine compressor is passed through a duct 122 into the chamber 124 formed between the inner shell 30 and housing 55. From this chamber 124 the cooling air flows through holes 120 into chamber 104, where it cools the bearing 82, thence through aperture 96 and over the rear surface of the turbine disc 102 into the stream of exhaust gases leaving the turbine. Cooling air also leaks between the surfaces 74, 80 over the outside surface of the end wall 58, and bearing 84. The bearings are lubricated by oil mist formed in the chamber 126 from oil issuing from conduit 129.