Abstract: A magnetic gas turbine sensor (25) for sensing the speed and/or torque of a shaft in a gas turbine engine, the sensor comprising a magnetically energisable pole piece (3), a magnet (2) associated with the pole piece and a conductive sensing element (4) wrapped or wound around the pole piece (3) and inductively coupled to the pole piece. The sensor includes a first sensor casing including a first inner fluid conduit (36) for fluid coolant, the first fluid conduit being inside the casing and running alongside and/or adjacent the pole piece, magnet and/or conductive sensing element, and the sensor also including a second sensor casing surrounding the first sensor casing and defining a second outer fluid conduit (37) for fluid coolant and at least partially surrounding the first fluid conduit.

Abstract: The present invention relates to a method of manufacturing a sensor for a high-temperature environment. The method comprises the steps of: depositing an electrically insulating material (108) to form at least one portion of a layer (112); depositing an electrically conductive material (110) to form at least one further portion of the layer (112); depositing successive layers (112), each layer being formed of the electrically insulating material (108) and/or the electrically conductive material (110), wherein the electrically conductive material (110) in each layer is deposited on at least a portion of the electrically conductive material (110) in the previous layer so as to form at least one electrically continuous portion extending through the layers; and fusing the materials.

Abstract: A liquid level monitoring system for monitoring the level of liquid in a tiltable tank, which may tilt or rotate in a tilt or rotation plane about a tilt axis. The system comprises a pair of pressure sensors comprising a first pressure sensor for sensing the pressure of the liquid in the tank at a first position located towards the bottom of a tank and a second pressure sensor for sensing the pressure of the liquid in the tank at a second position located a known pre-defined distance above the first sensing wherein the two sensing positions are located on a sensing line substantially orthogonal to and passing through a liquid surface dividing line, said liquid surface dividing line being the line along and extending past the surface of liquid in the tank whose position relative to the tank walls remains the same as the tank tilts about the tilt axis.

Abstract: The present invention provides a thermocouple probe (10). The probe includes a first pair of thermocouple wires (50) joined to form a first thermocouple junction (56) at a sensing tip (14) of the thermocouple probe and a cooling arrangement (20) defining a cooling pathway (34) adjacent to a cooled portion of the probe. The sensing tip projects beyond the cooling arrangement and is cooled during use by conduction to the cooled portion of the probe. The probe further includes a second pair of thermocouple wires (54) joined to form a second thermocouple junction (52) in the cooled portion of the probe and adjacent to the sensing tip. The present invention also provides a method and a system for determining the gas temperature (Tg) in a high temperature environment, such as a jet engine.

Abstract: The present invention relates to a system (100, 300, 400) for detecting abnormal movement of a gas turbine shaft. The system comprises: a magnetic circuit (104, 302, 402) comprising a first magnetic portion (110, 304) and a second portion (112, 404), and including at least one air gap between the first portion and the second portion; and a detection coil (106) wound around the first magnetic portion. The second portion is coupled to or moveable with the shaft to reduce the air gap, on axial movement of the shaft to change the reluctance of the magnetic circuit and thereby induce a voltage in the coil. The system may comprise a controller (108) for shutting off power to the gas turbine when the induced voltage exceeds a threshold voltage.

Abstract: A method is disclosed for tailoring the thermoelectric response of a thermocouple to that desired by a user. The method comprises the steps of; (a) selecting a first thermoelectric material, (b) selecting a second thermoelectric material having dissimilar thermoelectric properties to the first thermoelectric material, a thermocouple formed from the first thermoelectric material and the second thermoelectric material having a known thermoelectric response, and (c) modifying the chemical composition of at least one of the first thermoelectric material and the second thermoelectric material to produce a thermocouple having a tailored thermoelectric response. In specific embodiments, the chemical composition may be modified by selectively depleting one or more chemical elements from the thermoelectric material or by selectively adding, or increasing the proportion of, one or more elements to the thermoelectric material.

Abstract: An engine probe system for monitoring a moving engine element. The probe system includes a capacitive sensor (1) including a sensing electrode (5) defining one of the electrodes of a capacitor and an output lead for coupling the sensing electrode (5) to data processing means for monitoring changes in the capacitance of the capacitor including the sensing electrode. The output lead includes a first conductor for connecting the sensing electrode to the data processing means, an insulation jacket surrounding the first conductor, and a flexible conduit (11) surrounding the insulation jacket and defining a fluid passage between the insulation jacket and the flexible conduit.

Abstract: A cooled thermocouple arrangement (1) including a thermocouple (2) comprising two wires (3,4) joined at a first sensing end (5) to define a hot thermocouple function. At least a portion of the wires (3,4) are in thermal communication with a cooling arrangement, and the cooling arrangement has an inlet (14) for coolant and an outlet (15) for coolant. The thermocouple probe arrangement (1) includes a first inlet temperature sensor (21) for determining the temperature of the coolant as it enters the cooling arrangement, and a flow rate sensor (20) for determining the flow rate of coolant passing through the cooling arrangement. The thermocouple probe arrangement (1) includes connectors for connecting the outputs from the thermocouple (2), first inlet temperature sensor (21) and the flow rate sensor (20) to a correction data processor (23) whereby the data processor can correct the temperature sensed by the thermocouple to take account of the effect of the cooling arrangement.

Abstract: The invention provides a thermocouple assembly for use with a thermocouple harness in a gas turbine engine, comprising a thermocouple connected to a resistor, the resistor comprising a conductor, a mineral insulating material surrounding the conductor, and a metal sheath surrounding the conductor.

Abstract: There is disclosed a dual output compressive mode accelerometer having first and second output channels, comprising: a supporting base; first and second transducers mounted on the supporting base adjacent to one another, each transducer comprising a piezoelectric element and a seismic mass, the piezoelectric element positioned between the supporting base and the seismic mass; and a rigid mechanical coupling between the first and second transducers, the rigid mechanical coupling coupled to both of the first and second transducers above the supporting base.

Abstract: A sensor element for use in a backing sensor to monitor a gas turbine shaft. The sensor includes an oscillator circuit 30 having an oscillator and a resonance circuit 42, and a frequency detector 31 for monitoring the frequency of the oscillation circuit. Abnormal movement of the shaft cuts the circuit in the sensor along a cutting line (15). The cutting of the sensor changes the capacitance and/or inductance of the resonance circuit and thereby changes the frequency of oscillation.

Abstract: A system and method for measuring frequency which reduces the impact of noise. The system and method includes the steps of sampling a signal train over a first signal portion of the signal train, determining a first average period for the first signal portion (t1) of the signal train, sampling the signal train over a second signal portion (t2) of the signal train, wherein, the second portion of the signal train overlaps with the first signal portion, determining a second average period for the second signal portion (t2) of the output signal train, and then determining the average of the determined average periods.

Abstract: The invention provides a system for monitoring an operational parameter of a gas turbine, including a magnetic coupling between a signal source and a data output terminal. The magnetic coupling comprises a primary coil electrically connected to the signal source and wound around a first magnetic core section, and a secondary coil electrically connected to the output terminal but electrically isolated from the primary coil and wound around a second magnetic core section, wherein the first and second magnetic core sections are physically separated from one another.

Abstract: There is provided a variable reluctance sensor for sensing the speed or torque of a shaft in a gear box or gas turbine engine, comprising a magnetic pole piece a conductive wire wrapped around the pole piece a housing surrounding the pole piece, the housing having a front face and at least one side wall, wherein, in use, the front face is positioned proximate to an object to be sensed wherein the pole piece is rigidly fixed to the side wall of the housing. This arrangement reduces microphony in the sensor.

Abstract: The invention provides a thermocouple assembly for use with a thermocouple harness in a gas turbine engine, comprising a thermocouple connected to a resistor, the resistor comprising a conductor, a mineral insulating material surrounding the conductor, and a metal sheath surrounding the conductor.

Abstract: A sensor element for use in a backing sensor to monitor a gas turbine shaft. The sensor includes an oscillator circuit 30 having an oscillator and a resonance circuit 42, and a frequency detector 31 for monitoring the frequency of the ossilation circuit. Abnormal movement of the shaft cuts the circuit in the sensor along a cutting line (15). The cutting of the sensor changes the capacitance and/or inductance of the resonance circuit and thereby changes the frequency of oscillation.

Abstract: A system and method for measuring frequency which reduces the impact of noise. The system and method includes the steps of sampling a signal train (2) over a first signal portion (t1) of the signal train, determining a first average period for the first signal portion (t1) of the signal train, sampling the signal train over a second signal portion (t2) of the signal train, wherein, the second portion of the signal train overlaps with the first signal portion, determining a second average period for the second signal portion (t2) of the output signal train, and then determining the average of the determined average periods.

Abstract: There is disclosed a dual output compressive mode accelerometer having first and second output channels, comprising: a supporting base; first and second transducers mounted on the supporting base adjacent to one another, each transducer comprising a piezoelectric element and a seismic mass, the piezoelectric element positioned between the supporting base and the seismic mass; and a rigid mechanical coupling between the first and second transducers, the rigid mechanical coupling coupled to both of the first and second transducers above the supporting base.

Abstract: The invention provides a transformer probe for sensing movement of a body of magnetic material, having multiple output channels wherein the output in each output channel is substantially unaffected by faults in other output channels.

Abstract: A method (and corresponding apparatus) for monitoring gas turbine blades. The output from an eddy current sensor monitoring the movement of turbine blades past the sensor is processed to determine when the signal train from the sensor omits a signal or pulse corresponding to one of the shaft's full complement of blades. The signal processor compares sensed blade periods with average blade periods.