High-frequency water-content meter for coal dust

This device consists of a capacitance transducer and a circuit with parametric modulation; the transducer capacitance is a complicated function of several factors. For instance, the dielectric constant is affected by the grain-size distribution, particle density, contact resistance between particles, rock concentration, chemical composition, and so on. Also, the structure of the material is indirectly affected by the method of consolidation, on account of inelastic strain in the dispersion, together with any effects from mechanical processing of the material before measurement (mode of grinding), and so on. Many factors are difficult to estimate, which results in additional error in water-content measurement. The error may be reduced by determining the effects of the perturbing factors. The device is described and a mathematical description is formulated.