Abstract: An apparatus and method to measure the unburnt carbon content of fly ash. A microwave signal is transmitted through or reflected from a fly ash sample and the attenuation or phase shift of the signal received by a detector/detectors is determined with respect to the incident signal and is used to provide a measure of unburnt carbon content. The detectors may be antennae means which also launch the incident signal or may be a completely separate means. A preferred embodiment comprises a microwave oscillator for launching the microwave signal into a fly ash sample in a microwave resonant cavity. Detectors determine the attenuation of phase shift of the received signal with respect to a signal from a reference microwave resonant cavity by the fly ash sample, and a measurement of the unburnt carbon content is obtained.

Abstract: Apparatus and methods for the determination of moisture content of a sample carried on a conveyor belt. Microwave signals at a number of discrete frequencies within a range are transmitted through the sample and the phase shift of the received signals is averaged and combined with measurement of attenuation or mass per unit area to provide a measure of moisture content of the sample. The invention is applicable to measurement of moisture content of crushed coking and steaming coals.

Abstract: In the determination of the unburnt carbon content of fly ash, a microwave signal is transmitted through or reflected from a fly ash sample and the attenuation and phase shift of the transmitted or reflected signal from receiver antenna or circulator respectively, is determined with respect to the incident signal and used to provide a measure of unburnt carbon content. The invention is applicable to measurement of fly ash samples taken from a boiler outlet duct or for direct measurement of the unburnt carbon content of fly ash entrained in flue gas.

Abstract: Apparatus and methods for producing a signal or signals related to the moisture content of a substance using impedance, radio frequency loss or dielectric loss techniques are disclosed. Apparatus and methods for producing a signal or signals related to the density and/or thickness of a substance using backscattered gamma-rays are described. Apparatus and methods using a combination of a.c. impedance, radio frequency or dielectric loss and backscattered gamma-ray techniques for producing signals related to the moisture content, density and/or thickness of a substance are also described. Means and methods for determining the moisture content, density and/or thickness of the substance from the signal or signals are disclosed. The apparatus and methods are particularly applicable to determining the moisture content, density and/or thickness of coal and coke.

Abstract: An analysis system for a scanning electron microscope having a backscattered electron detector. The output of the detector is amplified, processed by an analogue to digital converter, multi-channel analyser, and digital conversion and processing circuit to generate a signal indicative of the atomic number factor of the specimen. Calculation of stoichiometric valence combinations of non-elemental specimens is also disclosed. A calibration device is also disclosed.