Abstract: A sensor probe for analysis of a fluid includes a base, and a pair of electrodes and a pair of shield members protruding from the base for insertion into the fluid. The electrodes have electrical oscillations generated therein for measurement of electromagnetic properties of the fluid, such as permittivity. The shield members are disposed outside the electrodes and have a dual purpose of electromagnetically shielding the electrodes and having vibrations generated therein for measurement of physical parameters of the fluid, such as density or viscosity. Thus, the single sensor probe can provide measurements of both electromagnetic properties and physical properties of the fluid.

Abstract: A sensor system for sensing the contents of a bore including a plurality of coils disposed behind a non-metallic lining. An oscillator circuit may be used to drive the coils to generate oscillating electromagnetic fields, and a detection circuit generates output signals from each coil representing a parameter of the electrical oscillations that depends on the contents of the bore. The coils may include a primary coil and a one secondary coil, wherein the oscillating electromagnetic field generated by the secondary coil has a lesser degree of interaction with the contents of bore than the oscillating electromagnetic field generated by the primary coil. The sensor system may use the output signal from the secondary coil to compensate the output signal from the primary coil for environmental effects.

Abstract: A sensor probe for analysis of a fluid includes a base, and a pair of electrodes and a pair of shield members protruding from the base for insertion into the fluid. The electrodes have electrical oscillations generated therein for measurement of electromagnetic properties of the fluid, such as permittivity. The shield members are disposed outside the electrodes and have a dual purpose of electromagnetically shielding the electrodes and having vibrations generated therein for measurement of physical parameters of the fluid, such as density or viscosity. Thus, the single sensor probe can provide measurements of both electromagnetic properties and physical properties of the fluid.

Abstract: An elongate component such as a drill string of drill pipes connected by joint sections inside a bore is sensed using at least one set of electromagnetic coils, the coils within the set being arranged at different angular positions around the bore facing the bore. There may be at least two sets of coils separated along the axial direction of the bore. Electrical oscillations are generated in the coils to produce oscillating electromagnetic fields that interact with the contents of the bore. A parameter of the electrical oscillations generated in each coil is detected. The detected parameters may be used to derive both (1) a measure of the axial position along the bore, and (2) a measure of the lateral position. The detected parameters may be used to derive a measure of electromagnetic properties of the contents of the pipe in a region adjacent each coil, thereby imaging the contents of the pipe.

Abstract: A sensor system for sensing the contents of a bore including a plurality of coils disposed behind a non-metallic lining. An oscillator circuit may be used to drive the coils to generate oscillating electromagnetic fields, and a detection circuit generates output signals from each coil representing a parameter of the electrical oscillations that depends on the contents of the bore. The coils may include a primary coil and a one secondary coil, wherein the oscillating electromagnetic field generated by the secondary coil has a lesser degree of interaction with the contents of bore than the oscillating electromagnetic field generated by the primary coil. The sensor system may use the output signal from the secondary coil to compensate the output signal from the primary coil for environmental effects.

Abstract: A sensor system comprises a marginal oscillator. A tank circuit comprises inductive and capacitive elements including a probe arranged to generate an electromagnetic field in a sensing region. A non-linear drive circuit drives oscillation of the tank circuit by supplying a differential signal pair of complementary signals across the tank circuit, sustaining the oscillation on the basis of at least one of the complementary signals. A detection circuit detects a characteristic of the oscillation of the tank circuit that is dependent on the electromagnetic properties of the contents of the sensing region and to derive a signal representing the at least one characteristic. The differential signaling provides numerous advantages, including improved accuracy and signal-to-noise.

Abstract: An elongate component such as a drill string of drill pipes connected by joint sections inside a bore is sensed using at least one set of electromagnetic coils, the coils within the set being arranged at different angular positions around the bore facing the bore. There may be at least two sets of coils separated along the axial direction of the bore. Electrical oscillations are generated in the coils to produce oscillating electromagnetic fields that interact with the contents of the bore. A parameter of the electrical oscillations generated in each coil is detected. The detected parameters may be used to derive both (1) a measure of the axial position along the bore, and (2) a measure of the lateral position. The detected parameters may be used to derive a measure of electromagnetic properties of the contents of the pipe in a region adjacent each coil, thereby imaging the contents of the pipe.

Abstract: A system and method for measuring the amount of sugar in a sample including measuring a solution of the sugar using oscillating electromagnetic fields generated in the sample at least two radio frequencies at which the electromagnetic properties of the solution differ. There are detected characteristics of the oscillating electromagnetic fields generated in the sample at each radio frequency that are dependent on the electromagnetic properties of the solution. A measure of the amount of sugar is derived from those characteristics. By combining measurements at different radio frequencies, the effects of changes in the ion concentration can then be removed to give an unambiguous measure for the sugar.

Abstract: A sensor arrangement for a rotatable element comprises two coils capable of being driven by oscillatory drive signals to generate electromagnetic fields. The coils are in different positions overlying a cylindrical portion of the rotatable element that has a target feature configured to interact with the generated electromagnetic fields when the target feature is aligned with the coils. Alignment between the target feature and the coils occurs at angular positions of the rotatable element that are offset for respective coils. Thus, by detecting a characteristic of the signals developed across the coils allowing derivation of an angular velocity signal representative of angular velocity. Also, the degree of interaction between the target feature and the electromagnetic fields varies with the axial position of the rotatable element, differentially between the coils, allowing derivation of an axial position signal representative of the axial position of the rotatable element.

Abstract: A cavity resonator system for measuring EM properties of the contents of a pipe portion comprises a primary resonator and a secondary resonator each with the same configuration comprising a conductive casing that defines a cavity and has openings for receiving a pipe portion, insulator material disposed inside the cavity, and antennae for generating and detecting a resonant EM field inside the cavity. In addition, the secondary resonator comprises at least one conductive screening ring that extends around the location occupied by a pipe portion for screening the interior of the ring from the field generated inside the cavity of the secondary resonator. By combining measures of parameters of the field from both resonators, the system may be used to generate a measure representative of EM properties of the contents of the pipe portion that is compensated for variation in the EM properties of the insulator material.

Abstract: A sensor system comprises a marginal oscillator. A tank circuit comprises inductive and capacitive elements including a probe arranged to generate an electromagnetic field in a sensing region. A non-linear drive circuit drives oscillation of the tank circuit by supplying a differential signal pair of complementary signals across the tank circuit, sustaining the oscillation on the basis of at least one of the complementary signals. A detection circuit detects a characteristic of the oscillation of the tank circuit that is dependent on the electromagnetic properties of the contents of the sensing region and to derive a signal representing the at least one characteristic. The differential signaling provides numerous advantages, including improved accuracy and signal-to-noise.

Abstract: A system and method for measuring the amount of sugar in a sample including measuring a solution of the sugar using oscillating electromagnetic fields generated in the sample at least two radio frequencies at which the electromagnetic properties of the solution differ. There are detected characteristics of the oscillating electromagnetic fields generated in the sample at each radio frequency that are dependent on the electromagnetic properties of the solution. A measure of the amount of sugar is derived from those characteristics. By combining measurements at different radio frequencies, the effects of changes in the ion concentration can then be removed to give an unambiguous measure for the sugar.

Abstract: A cavity resonator system for measuring EM properties of the contents of a pipe portion comprises a primary resonator and a secondary resonator each with the same configuration comprising a conductive casing that defines a cavity and has openings for receiving a pipe portion, insulator material disposed inside the cavity, and antennae for generating and detecting a resonant EM field inside the cavity. In addition, the secondary resonator comprises at least one conductive screening ring that extends around the location occupied by a pipe portion for screening the interior of the ring from the field generated inside the cavity of the secondary resonator. By combining measures of parameters of the field from both resonators, the system may be used to generate a measure representative of EM properties of the contents of the pipe portion that is compensated for variation in the EM properties of the insulator material.

Abstract: A sensor arrangement for a rotatable element comprises two coils capable of being driven by oscillatory drive signals to generate electromagnetic fields. The coils are in different positions overlying a cylindrical portion of the rotatable element that has a target feature configured to interact with the generated electromagnetic fields when the target feature is aligned with the coils. Alignment between the target feature and the coils occurs at angular positions of the rotatable element that are offset for respective coils. Thus, by detecting a characteristic of the signals developed across the coils allowing derivation of an angular velocity signal representative of angular velocity. Also, the degree of interaction between the target feature and the electromagnetic fields varies with the axial position of the rotatable element, differentially between the coils, allowing derivation of an axial position signal representative of the axial position of the rotatable element.

Abstract: Target sensor comprising: sensor probe having a resonance frequency that changes as the separation of the sensor probe and a target changes. Oscillator arranged to apply a radio frequency (RF) signal to the sensor probe, the oscillator having: control circuitry configured to regulate the frequency of the RF signal applied to the sensor probe to below the resonance frequency of the sensor probe. Detector arranged to detect an electrical characteristic of the oscillator that varies with the impedance of the sensor probe indicating an interaction of the sensor probe with the target.

Abstract: A target or rotor blade clearance measurement device is disclosed for indicating an interaction of a measurement probe with a target or rotor blade. In a preferred embodiment, the measurement device comprises a measurement probe containing a coil, a frequency source arranged to apply an input alternating signal to the measurement probe, and a frequency regulator arranged to regulate the input alternating signal at a frequency below the resonance frequency of the measurement probe. A detector is arranged to detect an output signal from the measurement probe at a frequency of the frequency source which varies in amplitude with an admittance and resonance frequency of the measurement probe. A circuit is arranged to scale the amplitude of the output signal detected by the detector according to the amplitude of the input signal provided by the frequency source.

Abstract: Position sensor (10?) and method for measuring the position of an object comprising, a sensing element and an oscillator (30) coupled to the sensing element such that an electromagnetic field is emitted from the sensing element. An output, arranged to provide a signal, varies in dependence upon a change in an electrical property of the oscillator (30). Change in object position relative to the sensing element alters the electrical property of the oscillator (30). Sensing element comprises at least one discontinuity arranged to perturb the signal at a predetermined object position. Alternatively, there is a temperature compensator in proximity to the sensing element and arranged to compensate the signal for changes in temperature.