Abstract: A gas turbine engine casing includes a plurality of coaxially interconnected ring members each provided with a flange at each of their axial extents to facilitate interconnection of the ring members by bolts; each ring member is provided with an integral array of inwardly directed stator vanes and carries an abradable sealing material to cooperate with the tips of rotor blades of the engine.

Abstract: A new nickel base superalloy suitable for compressor or turbine discs of gas turbine engines with fatigue crack propagation resistance equal to Waspaloy, tensile strength higher than Waspaloy and higher operating temperature than Waspaloy or UDIMET 720 family of alloys. The nickel base superalloy has a preferred composition by weight % of 14.0-19.0% cobalt, 14.35-15.15 Chromium, 4.25-5.25 Molybdenum, 1.35-2.15 tantalum, 3.45-4.15 titanium, 2.85-3.15 aluminium, 0.01-0.025 boron, 0.012-0.033 carbon, 0.05-0.07 zirconium, 0.5-1.0 hafnium, up to 1.0 rhenium, up to 2.0 tungsten, less than 0.5 niobium, up to 0.1 yttrium, up to 0.1 vanadium, up to 1.0 iron, up to 0.2 silicon, up to 0.15 manganese and balance nickel plus incidental impurities.

Abstract: A process and associated apparatus can automatically read a dot matrix code marking on an article even when the marking has been partly obscured or damaged in some way. The process comprises capturing a video image of the dot matrix code and correlating points on the captured image with a mask of expected dot appearance, using a known two-dimensional correlation technique. However, the correlation is performed in accordance with certain thresholding and mask adjustment criteria to improve read reliability and map the possible dot pattern in preparation for an attempt at reading the code. After automatically reorientating the map of possible dots to a read orientation if necessary, decoding of the pattern of possible dots is then attempted by comparing it with a datum grid representing rows and columns of valid dot matrix codes. The process can output a signal affirming that a valid code has been found.

Abstract: A gas turbine engine rotor disc (20) is provided with a plurality of cooling air supply passages (32) which are generally radially extending but are inclined in the downstream direction. Each passage (32) has a cross-sectional configuration which renders the ends (34) of the passages (32) less likely than normal to act as the site of hoop-stress induced cracks.

Abstract: A multiple layer erosion resistant coating on a substrate comprises alternate layers of tungsten and titanium diboride. All of the layers have the same thickness and preferably have thickness's of between 0.3 and 1 micrometer to give improved erosion resistance. The layers are produced by sputtering.

Abstract: A rotor disc for use in an electrical machine has circumferential rotor rims mounted thereon. The rotor rim comprises a row of alternate magnets and pole pieces. The magnets are tapered at their radially inner and outer extents and engage with correspondingly tapered surfaces on adjacent pole pieces to prevent relative physical movement therebetween.Each side of the radially inner and outer extents of the magnets may be tapered by a different amount to ensure correct orientation of the magnet polarity.

Abstract: An aircraft mounted gas turbine engine system comprises a three shaft propulsive gas turbine engine having three electrical generators; each one respectively associated with one shaft of the engine. Two of the electrical generators are additionally configured so as to function as electric motors so as to facilitate power transfer between the engine shafts. One of the electric generators provides the primary source of electrical power for the aircraft, while the remaining electrical generators provide electrical power for the engine and back-up power for the aircraft.

Abstract: The invention relates to a process for integrated evaporation and gasification of spent liquor from the production of cellulose, the gasification taking place in a reactor (1) at a pressure of from atmospheric pressure up to about 150 bar and at a temperature of about 500.degree.-1600.degree. C., by partial combustion of the spent liquor, a gas phase and a phase of solid and/or smelted material being formed in the reactor and being removed therefrom. The invention is characterized in that the combustion gas obtained from the reactor (1) by partial combustion of the spent liquor is brought together in direct contact with spent liquor, which may have been pre-evaporated, in a first stage--for example a venturi scrubber--, with alkali metal compounds, etc.

Abstract: A double annular combustor for a gas turbine engine is provided with annular arrays of main and pilot fuel injection modules. The main fuel injection modules are of the premix type so as to vaporise fuel. However, the pilot fuel injection modules are configured so as to function as both premix and airspray fuel injectors. During starting and low power conditions, the pilot fuel injectors are operational alone in their airspray mode. However during high power conditions, both the main and pilot fuel injection modules function as premix injectors. The arrangement reduces noxious emissions.

Abstract: A bladed rotor has blades fitted in grooves around its rim. The blades are prevented from making significant movement lengthways of their grooves by abutment members which are so formed as to enable fitting and removal without the use of special tooling.

Abstract: A ducted fan gas turbine engine is mountable on an aircraft structure via a pylon which includes a yoke. The yoke straddles the compressor module of the engine and is connected thereto at points diametrically opposite each other, thus obviating thrust links and the need for radial struts in the plane of the yoke.

Abstract: In a ducted fan gas turbine engine the fan module is connected rigidly to aircraft structure and flexibly to the core gas generator via flanged annular diaphragms (62,66) thus obviating the exertion of bending loads on the core gas generator casing when the fan intake experiences asymmetric aerodynamic loads.

Abstract: A gas turbine engine comprises turbine and compressor elements on a rotary shaft. The shaft is rotably mounted on preloaded axial thrust bearings. As it rotates in use the turbine and compressor elements create an axial thrust load on the bearings. According to the invention that axial thrust load is opposed by an electromagnetic coil which is energised to exert an axial force on the shaft in opposition to the axial thrust load and preferably completely balancing the axial thrust load. Bearing life is much extended.