GB814809A - Improvements in or relating to axial-flow turbines employing hot propellant media, especially gas turbines - Google Patents

Abstract

814,809. Turbines; stuffing-box substitutes. MASCHINENFABRIK AUGSBEHG-NURNBERG A.G. Sept. 19, 1955 [Oct. 22, 1954], No. 26730/55. Classes 110 (3) and 122 (5). An axial-flow turbine -comprising a rotor and an outer casing together with or incorporating inlet and outlet ducts has fixed parts, for guiding the propellant medium and disposed with narrow clearance about the surface of the rotor or rotor shaft, connected to a rigid frame disposed outside the outer casing and separately therefrom with no rigid connection between the fixed parts and the outer casing. A turbine shaft 4, Fig. 2, is mounted on a frame 1 by bearing blocks 2, 3. A guide vane carrier 8 with guide vane rings 9, 10 is supported in the horizontal centre plane by two journals 11, 12 in supporting bearings 13, 14 secured to the frame 1. A spigot at the lowermost point of the carrier 8 engages a guideway fixed to the frame 1. The carrier 8 and rings 9, 10 form the fixed parts for guiding the propellant medium disposed with narrow clearance about the surface of the rotor or rotor shaft. The outer casing 17 consists of an inlet duct 18, an outlet duct 19 and an elastic member 20. The casing 17 is supported on the frame 1 by arms 21 to 24 guided radially by pins 21<SP>1</SP> to 241. Shaft packings 25, 26 are supported by holders 27, 28 secured to the bearing blocks 2, 3. The space between the casing 17 and the packing holders 27, 28 is closed by laminated packing 29, 30. A modification in which the invention is applied to a turbine-driven supercharger is described. In another modification, Fig. 6, the rotor 105 is mounted in bearings 103, 104 supported on a liquid-cooled frame 100. Guide vanes 109 are secured to a carrier 110 composed of eight segments held together by flanges 111. The carrier 110 is rigidly connected at its ends to closed retaining rings 112, 113. The rings 112, 113 are connected by radial guide pins 114, 115 to closed rings 116, 117 mounted by horizontal arms on the frame 100. Guideways 119, 120 engaging projections 121, 122 guide the rings 116, 117 axially during expansion. The inlet and outlet ducts 108, 125 are connected by flexible V-shaped rings 127, 130 to the rings 112, 113 which are in turn connected to a sheet metal jacket 126 by similar V-shaped rings 128, 129. The jacket 126 constitutes the outer casing. Shaft 131 is sealed by labyrinth packings in holders 132, 133. Working fluid may be allowed to enter the space between the jacket 126 and carrier 100 to equalize thermal stresses. The blade shroud rings may be undivided and supported by radial guide pins in a divided carrier. An arrangement in which the rotor blades are bevelled at their outer ends together with correspondingly shaped shrouding is also described. In this arrangement, when - thermal expansion occurs, the clearance between the blades and shrouding is decreased.