Many types of solid material must be milled into finer particles for a proper dispersion within a liquid vehicle. The physical properties of resulting dispersions, called “grinds”, depend not only on actual size of individual particles, but also on the degree to which they are dispersed.
Fineness of grind gauges is utilized to indicate the thinness of grind or the presence of coarse particles or agglomerates in a dispersion. It does not determine particle size or particle size dispersion. Grind gauges are used in controlling production, storage and application of dispersion products produced by milling in the paint, plastic, pigment, printing ink, paper, ceramic, pharmaceutical, food and many other industries.
Fineness of grind gauges is a flat still block. On its surface there are one or two flat-bottomed grooves varying uniformly in depth, from a maximum at one end of the block to zero near the other end. Groove depth is graduated on the block according to one or more scales used. The dispersion degree is indicated in microns or “Hegman”. The Hegman scale ranges from 0 to 8 with numbers increasing as the particle size decreases.