Abstract: A hydraulic seal (15) for providing a seal between two concentric shafts (10,12) of a gas turbine engine comprises a radially outer element (16) that defines an annular oil reservoir (21) and a radially inner element (22) having an annular fin (24) that projects into the oil reservoir (21). The radially inner seal element (22) is attached to its associated shaft (10) by frangible shear pins (26). In the event of relative axial movement between the shafts (10,12) the shear pins (26) break, thereby ensuring that such shaft relative axial movement is not unduly inhibited.

Abstract: A method and apparatus for treatment of the fly ash are described wherein heavy metals are separated and wherein there is formed a leaching resistant slag; the fly ash is introduced into a reactor into an oxidizing gas stream which is heated to at least 2500 degrees C. in a plasma generator; the fly ash melts and forms liquid drops of slag and a carbonaceous or hydrocarbonaceous material is added to the gas stream which burns and supplies extra energy to the process; the ratio of oxygen and carbon is regulated so that the ratio CO.sub.2 /CO+CO.sub.2 is kept within the limits 0.4-0.

Abstract: A fuel injector (32) for a gas turbine engine combustion chamber (22) comprises a fuel injector nozzle (34) and a fuel feeding member (36). A wire mesh (76) is located in a space (74) defined between a hollow outer member (72) arranged around and spaced from a hollow inner member (70) of the fuel feeding member (36) and a fuel nozzle body (54) of the fuel injector nozzle (34). The wire mesh (76) rubs against the hollow outer member (72), the hollow inner member (70) and the fuel nozzle body (54) to frictionally damp vibrations of the fuel injector (32).

Abstract: An apparatus (42) for inspecting an as cast turbine blade (40), with impingement cooling passages (36) (see FIG. 2 ), comprises a vacuum pump (52) arranged to evacuate the interior of the turbine blade (40) through pipe (48) and valve (54) and a supply of steam (46) arranged to supply steam to the interior of the turbine blade (40) through the pipe (48) and a valve (50). An infrared camera (56) is arranged to view the outer surface (32) of the turbine blade (40) to detect hot spots produced on the outer surface (32) of the turbine blade (40) by jets of steam impinging on the inner surface (35) of the turbine blade (40) from the cooling passages (36). A processor (60) records the images produced by the camera (56) and analyses the images to determine if the cooling passages (36) have been formed and if they have been formed in the correct position.

Abstract: A hybrid control system executes tasks within a transaction which is executed in a given order. The order in which the tasks are executed is inversely proportional to their deadlines. The deadlines are assigned an initial deadline D, an initial maximum end-to-end delay of the transaction is calculated using the initial deadlines D and the given order of the tasks.The deadline of the task with the largest deadline is reduced by an increment to give a new deadline and if the task following it has an increment to give a new deadline. A new end-to-end delay is calculated using the new deadlines and the given order of the tasks. These steps are repeated until the new end-to-end delay does not exceed the desired maximum end-to-end delay.

Abstract: A combustion chamber assembly comprises a plurality of three stage lean burn combustion chambers (28) each of which comprises a primary combustion zone (36), a secondary combustion zone (40) and a tertiary combustion zone (44). Each of the combustion zones (36,40,44) is supplied with premixed fuel and air by respective fuel and air mixing ducts (76,78,80,92). A plurality of transition ducts (118) are provided at the downstream ends of the combustion chambers (28) to receive the exhaust gases. A damping ring (130) is connected to all of the transition ducts (118) by bolts (138) which pass through apertures (128) in flanges (126) on the transition ducts (118). The bolts (138) are biased by springs (142) such that frictional contact between the damping ring (130) and the flanges (126) damps harmful vibrations in the transition ducts (118).

Abstract: A dual mode spreader includes a wheel supported container having a bottom wall provided with discharge openings feeding to a rotationally supported spreader disk; a skirt is mounted relative to the container to be movable to alter the distribution pattern between a broadcast mode and a drop mode; a mode determining member is provided to move with respect to the container in coordination with movement of the skirt between the broadcast and drop modes of operation.

Abstract: A superconductor is placed inside a non-metallic cryostat filled with a cooling medium to maintain the superconductor in a superconductive state. A foil winding is connected in series with the superconductor by current leads and the cryostat is placed inside the winding. The winding has only a few turns in order to provide low inductance and low magnetic field when the superconductor is carrying its normal operating current. However in the event of a fault the increase in electrical current in the line winding causes a magnetic field to be generated parallel to the superconductor. The magnetic field generated exceeds the critical magnetic field of the superconductor. The magnetic field produced by the line winding triggers the superconductor to the resistive state.

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: In a gas turbine engine, the exit end of a combustion chamber of annular shape is suspended from the interior wall of the engine casing by an elbow structure which is detachably mounted on a flange by one of its two legs; the resilience of the elbow structure is improved by dove-tail shaped openings provided in the elbow structure with the narrowest section of the openings facing the bend line of the elbow structure to define with the opening of the other leg a gap that enables the elbow structure to function as a leaf-spring.

Abstract: A wax pattern assembly (10) is removed from a ceramic shell mould (30) by removing a support member (20) from the wax pattern assembly (10). The ceramic shell mould (30) is then heated to melt the wax out of the ceramic shell mould (30). The removal of the support member (20) provides a cavity (22) into which the wax may expand without cracking the ceramic shell mould (30). The support member (20) is provided with an external thread to allow it to be easily removed from the wax pattern assembly (10).

Abstract: The twin chopper of the present invention consists of a pair of roving choppers, each chopper being disposed on either side of a resin spraying nozzle. Each chopper comprises a rotatably driven cutter roller, a rotatable friction roller cooperating with the cutter roller, and an idler roller cooperating with the friction roller for feeding roving strands between the friction roller and the cutter roller. The outlet of the first chopper is so disposed relative to the nozzle as to discharge cut rovings over and onto the flat spray of resin while the outlet of the second chopper is so disposed relative to the nozzle as to discharge cut rovings under and onto the flat spray so that the resin spray is coated with roving cuts on both sides thereof from both choppers as the spray is directed onto the open mold surface.

Abstract: An annular seal is provided between a turbine rotor disc and the adjacent static structure. The seal comprises rotor fins extending from the turbine disc for rotation therewith and an abradable honeycomb layer radially outward of the rotor fins. The abradable honeycomb layer is located on the inner diameter of a sealing ring attached to the static structure. The sealing ring is moveable in an axial direction so that in operation the honeycomb has one axial position for transient conditions and an alternative axial position for stabilized running. The seal clearance can thus be optimised at the two axial positions reducing the leakage flow through the seal.

Abstract: An annular heat exchanger suitable for a gas turbine engine includes a first continuous sheet of material arranged in a spiral and a second continuous sheet of material arranged in a spiral. A first axially extending passage is defined between the first surface of the first sheet and the third surface of the second sheet and a second axially extending passage is defined between the second surface of the first sheet and the fourth surface of the second sheet. The first passage is closed at its axial ends by spiral seals between the first sheet and the second sheet. The second passage is open at its axial ends. A plurality of radially extending passages are provided to supply a first fluid at a first end into the first passage, to remove the first fluid from a second end of the first passage and to interconnect adjacent turns of the first passage. The passages extend radially through the second passage.

Abstract: Process for recovering chemicals and energy from black liquor, where the black liquor is gasified with CO, CO.sub.2, CH.sub.4, H.sub.2, and H.sub.2 S, in gaseous form, and Na.sub.2 CO.sub.3, NaOH and Na.sub.2 S, in the form of drops of smelt, being principally formed. The mixture of gas and smelt is cooled, in a first stage, by direct contact with a cooling liquid, whereupon a part of the cooling liquid is volatilized, and the smelt drops are separated off and dissolved in the remaining part of the cooling liquid with the formation of a liquid bath of green liquor. In a second stage, the gas is washed and saturated with moisture by direct contact with a washing liquid bath. After the gas has been washed in the second stage, energy in the form of thermal energy and condensation heat is recovered from the gas in an indirect condenser.

Abstract: The present invention relates to a digester for continuous cooking under raised pressure and temperature of fibre material in a vertical digester (1), where input of fibre material and cooking liquid takes place at the top of the digester, withdrawal of spent cooking liquor is carried out from at least one digester screening arrangement (1D) between the top and the bottom of the digester, and fibre material is fed out from the bottom (1C) of the digester, wherein the digester (1) is fitted with an additional digester screening arrangement (2) above the lowest screening arrangement (1B) of the digester so that the temperature in all the participatory cooking zones in the digester can be kept at essentially the same temperature level.