Abstract: The invention provides a chirped laser dispersion spectrometer having two tunable lasers each with a bias current supply, a chirp signal source to provide a matching chirp pattern, a beam splitter to produce a single beam from the two first and second tunable lasers and active-phase locking means to render the two beams phase coherent and to produce a radio frequency carrier signal capable of programmable phase modulation by means of an optical beat signal. The invention also provides a method for generating at least two optical frequency signals for use in a frequency modulation spectroscopy (FMS) process for the detection and/or measurement of molecular species in a gas mixture and a method for generating at least two optical frequency signals for use in a chirped laser dispersion spectroscopy (CLaDS) process for the detection and/or measurement of molecular species in a gas mixture.

Abstract: A method and system for reducing the effect of distortions on the baseline signal in an absorption spectroscopy system used for the detection or measurement of chemical species in a medium, whereby one or more correlations or convolutions are performed on the signal using a kernel function. The shape of the kernel function is chosen to reduce the influence of the baseline distortions on the processed measurand determination. The kernel function may also be chosen to enhance the absorption signal.

Abstract: A method and system for reducing the effect of distortions on the baseline signal in an absorption spectroscopy system used for the detection or measurement of chemical species in a medium, whereby one or more correlations or convolutions are performed on the signal using a kernel function. The shape of the kernel function is chosen to reduce the influence of the baseline distortions on the processed measurand determination. The kernel function may also be chosen to enhance the absorption signal.

Abstract: Provided is a compact apparatus for measuring the flow rate of a fluid. The apparatus includes a heated measure element and a heated reference element which are in substantially the same thermal environment within a measure cell, except that the measure element is situated in the path of the cooling fluid flow and the reference element is sheltered from this direct fluid flow. These elements are arranged as parallel and concentric planar elements that are essentially identical to each other with matching thermal characteristics. The elements are electrically connected in a Wheatstone bridge arrangement. Thermal exchange between the reference and measure elements is used to optimise noise rejection due to common mode background thermal effects. Measured parameters from the bridge can be used to derive the fluid flow rate.

Abstract: Provided are apparatus and methods for compensation of mechanical imbalance in a measurement apparatus, that provides options for increased accuracy and/or less expensive manufacture of a torsion balance. Orientation measurements are taken and an imbalance torque about the torsion spring's axis of rotation is determined, and used to calculate a compensation. The measurement apparatus of one embodiment includes a test body and a set of magnets for generating a first disturbing force on the test body in response to a paramagnetic gas. A conductor element in the magnetic field receives an electrical current that generates a second opposing force to the test body, under feedback control that varies the current until the test body achieves a balanced null position. The control signal required to achieve the fixed null position is measured.

Abstract: Provided are apparatus and methods for compensation of mechanical imbalance in a measurement apparatus, that provides options for increased accuracy and/or less expensive manufacture of a torsion balance. Orientation measurements are taken and an imbalance torque about the torsion spring's axis of rotation is determined, and used to calculate a compensation. The measurement apparatus of one embodiment includes a test body and a set of magnets for generating a first disturbing force on the test body in response to a paramagnetic gas. A conductor element in the magnetic field receives an electrical current that generates a second opposing force to the test body, under feedback control that varies the current until the test body achieves a balanced null position. The control signal required to achieve the fixed null position is measured.

Abstract: Provided is a compact apparatus for measuring the flow rate of a fluid. The apparatus includes a heated measure element and a heated reference element which are in substantially the same thermal environment within a measure cell, except that the measure element is situated in the path of the cooling fluid flow and the reference element is sheltered from this direct fluid flow. These elements are arranged as parallel and concentric planar elements that are essentially identical to each other with matching thermal characteristics. The elements are electrically connected in a Wheatstone bridge arrangement. Thermal exchange between the reference and measure elements is used to optimise noise rejection due to common mode background thermal effects. Measured parameters from the bridge can be used to derive the fluid flow rate.

Abstract: The present invention relates to a probe having an elongated main body with a proximal end for attachment to a wall of a duct or volume and a distal end that is disposed on the interior of the duct, such that the main body forms a measurement space through which the fluid is drawn for analysis.

Abstract: A sensor for determining the thermal conductivity of a fluid comprising a sensing module located within a housing having inlet and outlet ports for a fluid under test, the sensing module comprising a reference base surface and a sensing element spaced therefrom and having measure and reference sections, and there being provided electrical power monitoring means for monitoring the power through the measure and reference sections in order to generate a signal indicative of the power difference due to thermal conductivity through the fluid. The sensing element is a thick film printed disc with measure and reference resistors printed on it. All changes in the fluid are common to both the measure and reference sections except for the thermal conductivity of the fluid itself.

Abstract: Correlation spectroscopy measure is improved by correcting for cross interference. This is achieved through applying different gains to the output signals whereby the effect of background interferent species can be calculated and an automatic correction factor applied.

Abstract: The present invention relates to a probe having an elongated main body with a proximal end for attachment to a wall of a duct or volume and a distal end that is disposed on the interior of the duct, such that the main body forms a measurement space through which the fluid is drawn for analysis.

Abstract: A sensor for determining the thermal conductivity of a fluid comprising a sensing module located within a housing having inlet and outlet ports for a fluid under test, the sensing module comprising a reference base surface and a sensing element spaced therefrom and having measure and reference sections, and there being provided electrical power monitoring means for monitoring the power through the measure and reference sections in order to generate a signal indicative of the power difference due to thermal conductivity through the fluid. The sensing element is a thick film printed disc with measure and reference resistors printed on it. All changes in the fluid are common to both the measure and reference sections except for the thermal conductivity of the fluid itself.

Abstract: Correlation spectroscopy measure is improved by correcting for cross interference. This is achieved through applying different gains to the output signals whereby the effect of background interferent species can be calculated and an automatic correction factor applied.

Abstract: A measuring cell for use in apparatus for the measurement of the magnetic characteristics of a gas comprises means (5) defining a chamber (3) in which a test element (11) is suspended such as to be able to rotate about an axis, and means de inlet (1) and outlet port (4) means by which gas may flow through said chamber (3). The inlet port means is configured to cause the gas to flow in a substantially laminar flow regime. The chamber comprises a first portion (2) configured to cause the laminar gas flow to break up into a turbulent flow regime, and a second portion arranged to contain said test element. The gas flow enters from the first portion and enters the chamber in a flow pattern symmetrical in relation to the suspension position of the test element.

Abstract: A measuring cell for use in apparatus for the measurement of the magnetic characteristics of a gas comprises means (5) defining a chamber (3) in which a test element (11) is suspended such as to be able to rotate about an axis, amd means defining inlet (1) and outlet port (4) means by which gas may flow through said chamber (3). The inlet port means is configured to cause the gas to flow in a substantially laminar flow regime. The chamber comprises a first portion (2) configured to cause the laminar gas flow to break up into a turbulent flow regime, and a second portion arranged to contain said test element. The gas flow enters from the first portion and enters the chamber in a flow pattern symmetrical in relation to the suspension position of the test element.

Abstract: A gas measurement cell has a measurement element suspended to oscillate about a suspension axis in a magnetic field. A coil which oscillates with the element may have electrical signals applied to it to initiate oscillation and also provides an output whereby the frequency of oscillation can be measured.