Abstract: A meter is provided which can continuously measure the amount of water in a flowing mixture of water and lithographic ink. The mixture flows between the plates of a capacitor cell. This cell provides capacitance for an audio frequency oscillator. The output frequency of the oscillator is converted to a voltage which is proportional to the output frequency of the oscillator. This voltage is converted to a second voltage which is proportional to the logarithm of the first mentioned voltage and is also proportional to the concentration of water in the mixture. This second voltage is read out in a display device which can be set to read the water content of the mixture of water and ink.

Abstract: A meter and a method are provided for measuring the composition and flow rate of a coal slurry and other similar mixtures. The meter is a waveguide through which the mixture flows. Microwaves are propagated in the waveguide from a transmitter probe. A detector probe spaced from the transmitter probe receives signals from the microwaves. Those signals are processed to determine a characteristic frequency of the waveguide or the wavelength of the propagating microwave, which are related to the composition of the mixture within the waveguide. A second transmitter and detector pair determines these properties for another portion of the waveguide. Differences in the frequencies resulting from inhomogenuities in the mixture are cross correlated to determine the flow rate of the mixture.