Abstract: A variable area nozzle for a turbomachine comprising, a duct 25 at least one wall of which is defined by a fixed portion 26 and two movable plates 29,30 located downstream of a downstream edge of the fixed portion 26. A first of the plates 29 is movable in a direction along the duct 25 relative to the fixed portion 26 and a second of the plates 30 is pivotally mounted at its upstream end on a downstream end of the first plate 29. An outer wall 34 surrounding the panels 29,30 extends downstream beyond the said downstream edge of the fixed portion 26. A seal plate 36 pivotally attached to the outer wall downstream of the downstream edge of the said fixed portion 26 is pivotally attached to one or more of the plates 29,30 and the seal plate 36 together with the plates 29,30 and the outer wall 34 define a pressurizable chamber 41 on that side of the plates 29,30 remote from the interior of the nozzle.

Abstract: A crucible used in a powder pack plating process has an aperture below the upper surface of the powder pack to allow a density driven flow of the plating gas generated by the powder pack to move through the powder pack.

Abstract: A labyrinth seal positioned between a turbine rotor and inner platforms of vanes of a turbine assembly controls the leakage flow of fluid from a chamber to the flowpath through the turbine assembly. The labyrinth seal is divided into two parts by a second chamber positioned between two adjacent fins of the labyrinth seal. The chamber is located at a predetermined position in the seal such that a predetermined pressure, sufficient to supply fluid to cool a stage of turbine rotor blades in the turbine assembly, is selected. The second chamber is interconnected to the turbine blades by passages, and a chamber. The pressure of fluid in the second chamber is less than that which would normally exist in the second chamber, because fluid is being supplied from the second chamber to the second stage of turbine rotor blades. The flow of fluid from the second chamber, through the second part of the labyrinth seal, to the flowpath through the turbine is therefore reduced.

Abstract: A launder system for supplying molten metal from a crucible to a casting mould or a secondary process has a nozzle with a filter positioned therein to filter the molten metal as it flows through the nozzle. The nozzle and filter assembly is removably attachable to the launder system, and is used once and then replaced by a new nozzle and filter assembly. Efficient cleaning of the molten metal thus occurs without an increase in blockage due to the filter. Additionally, the scrapping rate of the launder system is reduced, allowing multiple usage of the launder.

Abstract: A rotary aerofoil blade is provided with closed cycle sodium cooling. The blade has a shank portion which contains a chamber which is in turn partially occupied by an air cooled core member. The core member serves to condense sodium vapor from the aerofoil portion of the blade. Gutter members within the chamber capture the condensed sodium as it is cenrifuged towards the aerofoil portion and direct it into a further chamber within the blade shank portion from when it flows into passages adjacent the external surface of the aerofoil portion. The high temperature of the aerofoil portion vaporizes the sodium which is then pumped by vapor pressure gradients back to cooled core member whereupon the cycle is repeated.

Abstract: The present invention relates to cooled gas turbine engine aerofoils particularly for turbine stator vanes or tubine rotor blades. The leading edge region of a hollow aerofoil is provided with rows of cooling air passages, which are arranged, in operation, to direct cooling air in the opposite direction to the local flow of the hot gas stream. The cooling air passages are substantially parallel, and have relatively large diameters to reduce the possibility of blockage of the cooling air passages by sand. An air guide tube in the hollow aerofoil is provided with large apertures at its leading edge to minimize the area for sand to adhere to.

Abstract: A shroud liner has a hooked downstream end passing between a stator vane and a casing so that in operation the gas loads on the vane cause the liner to be held between the vane and the casing. The shroud liner also has a resilient upstream end fitting between a second stator vane and the casing so that in operation gas loads on the vane cause it to move towards the casing, compressing the shroud liner. As a result the shroud liner is securely held in place at its downstream end, but can slide relative to the casing and vanes at its upstream end to allow for thermal expansion.

Abstract: A stepped shaft passes from a high pressure region, through a vented low pressure region and into an intermediate pressure region. The high pressure region is separated from the low pressure region by a first brush seal and the intermediate pressure region is separated from the low pressure region by a second brush seal. The radius of the shaft is greater at the first brush seal than at the second. This second brush seal bears a circumferential flange on its backplate to deflect fluid leaking between the first brush seal and the shaft radially inwards, the radius of the flange is less than the radius of the shaft at the first brush seal.

Abstract: A shroud ring suitable for the turbine of a gas turbine engine comprises an annular heat pipe with radially inwardly directed flanges which are bridged by a plurality of abutting tiles so that together they define an annular chamber. The annular chamber serves to provide a thermal barrier between the tiles and a major portion of the heat pipe. The operating temperature of the shroud ring is thus reduced thereby ensuring reduced radial expansion.

Abstract: Apparatus and a method for attaching individual blades to a disc rotor of a BLISK is described. Blade blanks or preforms are gripped between adjustable jaws of a rigid frame member of a linear friction bonding machine, and are attached in a non-rotational friction bonding operation. Blade preforms may be finished to final airfoil shape in a further operation after attachment. The technique is suitable for repair work or original manufacture.

Abstract: A turbine suitable for a gas turbine engine is provided with a stage of rotary aerofoil blades which is surrounded by a shroud ring made of silicon nitride. In order to minimize load transfer between the shroud ring and the turbine casing the shroud ring is radially supported by and radially spaced apart from the turbine casing by a woven wire mesh array.

Abstract: A gas turbine engine is provided with an annular array of rotor blades which are surrounded by a shroud ring. The shroud ring includes a number of adjacent heat pipes which are of the variable conductance type. The heat pipes each have a portion which is externally of the shroud ring which portion is in turn divided into two parts. The first part is exposed to a flow of cooling air while the second part contains a buffer which operationally varies the conductance of the heat pipe, in accordance with the temperature of air which is tapped from the high pressure compressor of the engine. This serves to ensure that the shroud ring remains substantially isothermal and provides control over the clearance between the tips of the rotary blades and the shroud ring through thermal control of the shroud ring.

Abstract: A program-controlled heat management system for an aircraft's bypass gas turbine (turbofan) engine installation, in which the engine's fuel system is put into direct heat exchange relationship with the engine's own oil system, and with an engine-driven electrical generator's oil system, by means of respective fuel/oil heat exchangers and also into selective indirect heat exchange relationship with a variable proportion of the engine's bypass air means of an engine oil/air heat exchanger. The fuel system is switchable between four different fuel flow configurations in order to vary the heat flows between the fuel system and the oil systems, two of the fuel flow configurations also involving recirculation of fuel from the engine's fuel system to a fuel tank in the aircraft wing in order to put the fuel system into selective heat exchange relationship with the tank and hence with the airstream passing over the wing.

Abstract: A fluid temperature measuring device (10) comprises a substrate (12) upon which is deposited a first insulating layer (14). A first metallic layer (16) is sputtered onto the first insulating layer (14), a second insulating layer (18) is deposited on the first metallic layer (16) and a second metallic layer (20) is sputtered onto the second insulating layer (18).The second metallic layer (20) is thin and has a low heat capacity so that it responds quickly to changes in temperature of the fluid. The first metallic layer (16) is thin and is heated by supplying an electric current from an electrical power supply (22) to maintain the first metallic layer (16) at the same temperature as the second metallic layer (20).The second metallic layer (20) is electrically connected to an electrical resistance measuring device (24) which detects temperature changes of the fluid by detecting corresponding changes of the electrical resistance of the second metallic layer (20).

Abstract: To analyse its spectrum, a radio signal is beat with an intermediate signal in a heterodyne circuit having a local oscillator sweeping a range of intermediate frequencies. The oscillator signal also beats with the output from a comb generator to produce signals marking intervals in its frequency sweep. The magnitude of the filtered intermediate frequency signal is measured between intervals marked by the frequency interval signals to output a frequency spectrum of the input signal. Preferably, the intermediate frequency signal is filtered in a homodyne demodulating unit employing a further local oscillator tuned to the intermediate frequency. A spectrum data display employs a memory storing the signal magnitudes at successive frequency steps at respective addresses associated with individual frequency steps. The magnitude values are assigned to their addresses by the spectrum frequency interval signals.

Abstract: A brush seal is formed by bristles tightly packed between two annular sideplates having different inner radii and secured to a housing. The free ends of the bristles are in rubbing contact with a shaft. The differential pressure which the seal can support is increased by loading the bristles against the annular sideplate having the smaller inner radius, the loading force being such that the bristles can still move in the plane of the seal. As a result the amount of relative movement of shaft and housing that the seal can tolerate is not reduced.

Abstract: A gas turbine engine is provided with a thrust reverser. In order to avoid inadvertent operation of the thrust reverser when the gas turbine engine is not running, a safety switch is provided on the engine at a position remote from the thrust reverser. The thrust reverser control system is arranged so that when the engine is not running the thrust reverser will only operate when the safety switch is being manually operated.

Abstract: Two titanium alloy turbine components are diffusion bonded together by preparing mating surfaces of the components to a high degree of smoothness, putting the surfaces in mating abutment, placing the components within a yoke in a vacuum furnace, evacuating the furnace, increasing the temperature of the furnace to about 960.degree. C., applying pressure across the interface between the components by means of a pressure bag between the yoke and the components, maintaining the vacuum, temperature and pressure for about 30 minutes, back filling the furnace with argon, increasing the pressure of argon to about 1000 atmospheres, maintaining that pressure and temperature for about two hours, and then reducing the pressure to atmospheric and removing the diffusion bonded components from the furnace.

Abstract: In a high pressure compressor stage of a gas turbine engine an array of rotor blades is mounted on a rotatable disk or drum and a static shroud is made up of a number of shroud segments. Each segment is provided with two hook portions which each locate through a respective slot or aperture formed in a generally tubular casing structure. The hook portions engage the outer surface of the casing whilst the ends of the shroud members press upon the inner surface of the casing to create an assembly strain which holds each shroud member firmly in position. Cooling air holes are provided in the casing and the shroud segment.

Abstract: A sealing plug .Iadd.assembly .Iaddend.includes a plug and a housing.Iadd., .Iaddend.the plug and the housing including co-operating .[.means.]. .Iadd.structures .Iaddend.whereby they may be secured together, the plug including two circumferentially extending grooves within which O ring seals are located, and the housing .[.including an aperture.]. .Iadd.having a bore .Iaddend.within which the plug is adapted to be located, the housing also including a spring loaded radially extending pin which projects into the .[.aperture.]. .Iadd.bore .Iaddend.and which is adapted to project into either of the grooves within the plug if an O ring is omitted, thus preventing the plug being secured with the housing by the co-operating .[.means.]. .Iadd.structures.Iaddend..