GB723882A - Improvements in the construction of rotors for steam- and gas-turbines - Google Patents

Abstract

723,882. Elastic-fluid turbines. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Sept. 5, 1952 [Sept. 5, 1951], No. 21000/51. Class 110 (3). In a multi-stage steam or gas turbine rotor arranged to be supported at or near its ends and comprising two or more coaxial rotor sections provided each at an end adjacent another section with a radially-extending flange, the flanges cooperate mutually in pairs for securing together the sections at their abutting faces and form in respect of each such pair a blade-carrying disc and the sections are further secured together by an axial bolt or like screwed rod for holding the abutting faces of adjacent sections in contact with each other. The rotor consists of a double flow section 1, two intermediate sections 2, 3 and two exhaust sections 4, 5 which are interconnected by a flange connection as shown; each pair of cooperating flanges 6 constitute a single bladecarrying disc for impulse blading. The flanges 6 are interconnected by one or more rings of countersunk rivets or are welded together along a groove disposed about the periphery of the abutting flanges or at the bottom of a bladereceiving groove. The exhaust section 5 has an extension 7 forming a journal 8 and a coupling 9 for connection to an electric generator whilst the exhaust section 4 is adapted to be secured to another turbine arranged in series therewith. The sections 1 ... 5 are also connected by a bolt 11 which has a portion 16 of larger diameter than that of the bore of the sections and has three slits 17 which are spaced 120 degrees apart and extend to the bore 18 of the bolt. The bore 18 is used for cooling purposes and serves for the insertion of a heater for heating the bolt during its assembly, thereby increasing its length to effect subsequent tightening of the nut which is secured by locking plates 19, 20. The flanges 6 have contact areas 22, 24 and a circular spigot and socket connection 25; the spigot being formed on the upstream member. Recesses 23 are formed in one of the flanges 6 on either side of the contact area 22, the outer diameter of which is about the same as that of the rotor body diameter at the root of the blade discs whilst its inner diameter is about three-quarters that of the outer diameter. In a modification, the section 1 is formed in two parts having abutting flanges which are interconnected by studs and nuts. Each section of the rotor is provided with a recess which houses a ring, as described in Specification 723,462. The ring resiliently engages the abutting rotor sections and the bolt passing therethrough. A flexible steel sleeve, the length of which is preferably not less than its diameter, is positioned between the head of the bolt and the corresponding rotor section; the end of the sleeve in contact with the rotor being forced to expand therewith by means of friction, mating grooves, keys or pins. The sections 1 ... 5 are constructed from different quality steels to suit the operating conditions of the parts.