The Hardgrove Grindability Tester is the ASTM recommended apparatus for determining the grindability of coal, petroleum coke and for ascertaining the ease of pulverization of a wide variety of materials. The Hardgrove grindability Tester is essentially a miniature pulverizer. Eight 1- inch balls roll in a stationary ring driven from above by a rotating ring. A constant known pressure is applied by weights to the upper ring.  A counter  automatically cuts off the motor driving the ring after 60 revolutions.

The Hardgrove Tester gives reproducible results because the work done on the sample is so closely controlled. Since the sample is always in the path of the rolling balls, the energy is evenly distributed throughout the sample. The Hardgrove Grindability Tester is simple and clean operating. No sample is lost as the pulverizing takes place in a closed compartment. After releasing the lower portion of the grinding unit by the 2 thumbscrews, it can be removed and cleaned with a brush.

The Hardgrove Grindability Tester comes complete with full directions, automatic revolution control switch, weights, built in gear reduction motor and a sample of standard coal.