Abstract: Combustion chamber includes a primary stage fuel burner to supply fuel into a primary combustion zone and secondary stage fuel burner supplies fuel into a secondary combustion zone. A sensor is positioned downstream from combustion chamber measuring concentration of one or more compounds. The sensor sends measurements of the concentration of compounds to a processor. The processor compares the measured concentration of the compound with a first threshold value and a second threshold value. The processor supplies more fuel to the primary stage fuel burner if the measured concentration is higher than the first threshold value, supplies more fuel to the secondary stage fuel burner if the measured concentration is higher than the second threshold value, maintaining fuel supply to the primary and secondary stage fuel burners if the measured concentration is lower than the first threshold value and lower than the second threshold value.

Abstract: A pump has a brushless electrical motor including a stator assembly and a rotor ring arranged externally of the stator assembly. The pump further has a centrifugal impeller operatively connected to the rotor ring such that the electrical motor rotates the impeller. The impeller is configured to raise the pressure of a fluid which flows through the impeller between an inlet and an outlet thereof. The pump is configured such that a portion of the raised pressure fluid flow is diverted to form a recirculation flow which circulates through and cools the electrical motor before being returned to the impeller for re-pressurisation thereby.

Abstract: An engine fuel control system includes a fuel metering valve that controls the flow of fuel between supply and delivery lines which delivers fuel to engine burners. The fuel control system includes a fixed displacement main pump which receives fuel from a low pressure source and delivers the fuel at a first high pressure to the supply line, an augmenter pump which receives fuel from the low pressure source and delivers the fuel at a second high pressure to one or more fuel-pressure operated auxiliary engine devices, and a start valve which is actuated at low engine speeds to open a flow path which diverts fuel delivered by the augmenter pump away from the auxiliary engine devices to the supply line to augment the fuel delivered thereto by the main pump, the start valve being actuated at higher engine speeds to shut the flow path.

Abstract: A fuel pumping unit has a low pressure pump, a high pressure pump, and a drive input which drives the low and high pressure pumps. The low pressure pump supplies, in use, fuel at a boosted pressure to the high pressure pump. The fuel pumping unit further has a low pressure housing containing the low pressure pump, and a high pressure housing containing the high pressure pump. The housings are joined together at a housing interface. The drive input is contained in one of the housings, whereby drive from the drive input is transferred across the interface to the pump in the other housing. The housing interface includes a gap which interposes between the high pressure pump and the low pressure pump. A layer of substantially stagnant fuel is trapped, in use, in the gap to reduce heat transfer from the high pressure pump to the low pressure pump.

Abstract: An engine fuel control system includes a metering valve to control fuel flow between the supply and delivery line with a pressure drop control regulating the pressure across the valve and maintain a substantially constant pressure across the valve. The fuel control system includes a backup system controllable by a pullback signal to operate the pressure control, thus increasing the pullback signal reducing the fuel flow between the supply and delivery line. The fuel control system detects a start of an engine overthrust event, and when the upward runaway is caused by the arrested overthrust event. The fuel control system's controller which (i) determines the overthrust detection, the pullback signal increase rate and the pullback signal offset, (ii) sends the pullback signal to the backup system at the rate of increase, and (iii), reduces the pullback signal to the backup system when the upward runaway is arrested by the offset.

Abstract: A coupling unit has an electrical-connector for push-fit electrical connection in the coupling unit axial direction to a mating electrical-connector of a unit. The electrical-connector and mating electrical-connector have engagement formations permitting push-fit connection only when the electrical-connector is in predetermined rotational alignment about axial direction with the mating electrical-connector. The coupling unit has a backshell in fixed rotational relationship with the electrical-connector and extending rearwardly therefrom to house, in use, one or more leads extending rearwardly from the electrical-connector. The coupling unit has coaxial actuation sleeve surrounding the backshell. The actuation sleeve axially moves to effect push-fit connection.

Abstract: A combustion staging system has a splitting unit receiving and splitting metered fuel flow into out-going pilot and mains flows; pilot and mains fuel manifolds receiving the pilot and mains flows; and parallel mains flow scheduling valves distributing the mains flow. The mains flow scheduling valves pass the pilot fuel flow to injector pilot discharge orifices. Each mains flow scheduling valve has a chamber containing a piston, the chamber to a piston pilot side communicating with the pilot fuel manifold and the chamber to a mains side of the piston communicating with the mains fuel manifold. The piston is biased towards a closed pilot-only position preventing flow out of the chamber mains side to the injector mains discharge orifice. The piston is movable under increased pressure in the mains fuel manifold to an open pilot-and-mains position allowing flow out of the chamber mains side to the injector mains discharge orifice.

Abstract: A variable vane control system for controlling the angle of rotation of a circumferential row of variable vanes of a gas turbine engine. The control system includes a mechanical linkage operable to rotate the variable vanes, one or more actuators for operating the linkage and one or more position sensors for detecting the respective actuation positions of the one or more actuators. The control system further includes a linkage position signalling switch for signalling that the mechanical linkage is at a calibration position corresponding to a predetermined rotation angle of the vanes. The control system further includes a controller for controlling the one or more actuators and thereby controlling the angle of rotation of the vanes, based on the detected actuation positions which the controller correlates with vane rotation angle.

Abstract: A combustion staging system for fuel injectors of a multi-stage combustor of a gas turbine engine has pilot and mains fuel manifolds distributing fuel to the injectors. A splitting unit splits a fuel flow and sends portions of the flow to pilot and mains fuel manifolds to perform staging control of the combustor. The splitting unit can deselect the mains manifold so that there is no flow into the combustor from the mains manifold. A cooling flow recirculation line provides a cooling flow of fuel to the mains manifold when that manifold is deselected so that the mains manifold remains primed with relatively cool fuel. A return section collects the cooling flow from the mains manifold. One or more fuel pressure sensors detect pressure of the cooling flow on the recirculation line. A control arrangement closes off the recirculation line when the pressure sensor(s) indicates failure of the cooling flow.

Abstract: A fuel staging system is described which comprises a staging valve 28 operable to divide a metered fuel supply between a pilot delivery line 18 and a mains delivery line 16, and a recirculation valve 54 connected to the mains delivery line 16 and operable to permit a recirculation fuel flow to be supplied to the mains delivery line 16 when the staging valve 28 occupies a position in which substantially no fuel is delivered to the mains delivery line 16 through the staging valve 28.

Abstract: Tool for extracting annular carbon face seal from bore of equipment which seal is installed. Tool has extraction-tube for insertion into bore at entrance so, when extraction-tube is fully inserted into bore, multi-legged collet formed at distal-end of extraction-tube located within seal and proximal-end of extraction-tube accessible at entrance of bore. Tool has elongate-member extending along central passage of extraction-tube. Wedge element provided at distal-end of elongate-member located at mouth of collet. Proximal-end of elongate-member accessible at proximal-end of extraction-tube. Tool has support for reacting axial extraction force applied to extraction-tube to equipment. Tool has first-actuator at proximal-end of elongate-member. Tool configured so first-actuator causes wedge element to be pulled into collet, thereby expanding collet and causing to grip inner surface of seal.

Abstract: A method of detecting a shaft break in a turbine engine is provided. The shaft connects a torque-exerting turbine of the engine to a torque-receiving unit of the engine. The method includes: receiving repeated measurements of the rotational frequency of the torque-receiving unit and the rotational frequency measurements of the turbine; determining from the measurements an amount of shaft twist between the turbine and the torque-receiving unit; comparing the amount of twist with a threshold twist value; and signalling a shaft break when the amount of twist exceeds the threshold twist value and a pre-condition is met. The pre-condition includes determining from the measurements that the turbine rotational speed is greater than the simultaneous torque-receiving unit rotational speed by a threshold speed value.

Abstract: An apparatus for measuring the circumferential distribution of temperature in a fluid, comprising a plurality of sensor ladders, each incorporating a plurality of temperature sensors, wherein a first one of the sensor ladders partially overlaps a second one of the sensor ladders, part of the first sensor ladder not overlapping the second sensor ladder.

Abstract: A fuel system comprises a fuel pump operable to deliver fuel through a supply line to a pressure raising valve, the pressure raising valve including a control chamber, the fuel pressure within the control chamber controlling a minimum pump pressure differential, and an actuator control servo-valve operable to control the supply of fuel from the supply line to an actuator control line, wherein the actuator control servo-valve further controls the pressure of fuel applied to the control chamber of the pressure raising valve.

Abstract: A fuel system comprises a fuel actuation arrangement 28 operable to split a metered flow of fuel into at least a first stream and a second stream, a control unit 25 controlling the operation of the fuel actuation arrangement 28, and wherein the control unit 25 controls the operation of the fuel actuation arrangement 28 in response to the output of a temperature sensor 34 sensitive to a gas temperature downstream of the high pressure compressor 14 of an associated engine and the output of a gas sensor 24 sensitive to at least one parameter of the composition of a gas downstream of a combustor 15 of the engine.

Abstract: A fuel system comprises a supply unit operable to deliver a metered supply of fuel to a supply manifold, a staging valve operable to control the supply of fuel from the supply manifold to a pilot outlet and a main outlet, and control means operable to control the operation of the staging valve to control whether fuel is delivered through the pilot and/or main outlet thereof.

Abstract: A fuel pumping unit has a low pressure pump, a high pressure pump, and a drive input which drives the low and high pressure pumps. The low pressure pump supplies, in use, fuel at a boosted pressure to the high pressure pump. The fuel pumping unit further has a low pressure housing containing the low pressure pump, and a high pressure housing containing the high pressure pump. The housings are joined together at a housing interface. The drive input is contained in one of the housings, whereby drive from the drive input is transferred across the interface to the pump in the other housing. The housing interface includes a gap which interposes between the high pressure pump and the low pressure pump. A layer of substantially stagnant fuel is trapped, in use, in the gap to reduce heat transfer from the high pressure pump to the low pressure pump.

Abstract: A fault tolerant electric drive system includes an alternator, a motor controller and an electric motor, wherein the alternator and motor each have a plurality of corresponding independent phase windings, the motor controller having a plurality of independent phase drives corresponding to the phase windings, and a plurality of independent electric drive phases is defined by connecting each corresponding phase winding of the alternator and motor to a corresponding phase drive of the motor controller.

Abstract: An engine fuel control system includes a metering valve to control fuel flow between the supply and delivery line with a pressure drop control regulating the pressure across the valve and maintain a substantially constant pressure across the valve. The fuel control system includes a backup system controllable by a pullback signal to operate the pressure control, thus increasing the pullback signal reducing the fuel flow between the supply and delivery line. The fuel control system detects a start of an engine overthrust event, and when the upward runaway is caused by the arrested overthrust event. The fuel control system's controller which (i) determines the overthrust detection, the pullback signal increase rate and the pullback signal offset, (ii) sends the pullback signal to the backup system at the rate of increase, and (iii), reduces the pullback signal to the backup system when the upward runaway is arrested by the offset.

Abstract: A staging valve arrangement is described that comprises an arrangement of electrically driven staging valves that are located, in use, in the high temperature core zone of an engine. Each staging valve may comprise a housing having an inlet, a pilot flow outlet and a mains flow outlet, a valve member movable between a closed position in which the mains flow outlet is closed and an open position in which the mains flow outlet is open, a motor operable to drive the valve member for movement, and a cooling arrangement.