Salunda Limited

Rosemount Aerospace Limited

Oxford Rf Sensors Limited

Peter Wherritt

Martin Roy Harrison

Richard William Phillips

Philip Samuel Pickles

Chad P Stay

John Francis Gregg

Alexy Davison Karenowska

Richard W Phillips

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.

Sensing system using a marginal oscillator

Fluid sensor and method comprising: an oscillator having operating characteristics. Permittivity sensing element coupled to the oscillator and arranged to alter the operating characteristics of the oscillator in response to changes in permittivity presented to the permittivity sensing element. Reference element comprising an electrical impedance having a real and imaginary component controllably coupled to both the oscillator and the permittivity sensing element and arranged to alter the operating characteristics of the oscillator. Method of measuring the composition of a fuel comprising the steps of: measuring a real permittivity of the fuel. Measuring an imaginary permittivity of the fuel. Determining a proportion of biodiesel in the fuel based on the measured real permittivity. Determining a proportion of unrefined oil in the fuel based on the measured imaginary permittivity.

Permittivity sensor

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.

Sensor arrangement for a rotatable element

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.

Cavity resonator system

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.

Target sensor

An electromagnetic field sensor assembly for blade tip clearance measurement in a gas turbine engine is disclosed that includes a ceramic sensor body, a multi-layered wire coil wound about a distal end portion of the sensor body for producing an electromagnetic field, a ceramic well enclosing the sensor body and the coil, and a metallic housing surrounding the well and having an open distal end.

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Oxfordshire, United Kingdom

Peter Wherritt