ASTM D409/409M

Hardgrove Grindability Tester measures relative ease of pulverization of coals compared to standard coals in accordance with ASTM D409 Hardgrove Machine Method. 
The resulting Hardgrove Grindability Index (HGI) provides a measure of energy required in a grinding process or a measure of yield for a given energy input. 
A prepared 50g sample of No. 16—No. 30 sieve size coal and eight 1in (25.4mm) diameter polished steel grinding balls are placed in a stationary bowl having a machined circular track.
An upper grinding ring with matching track is rotated at 20rpm to drive the balls while a fixed load of 64lb (29kg) is maintained by weighting the motor-driven spindle attached to the upper ring. 
A counter/switch assembly automatically stops the tester after 60 revolutions, and amount of grinding is determined by sieving on a No. 200 sieve. 
The unit is made from durable steel and cast iron materials throughout to ensure reliable, maintenance-free operation. 
Upper and lower grinding elements and 8 grinding balls are included with each model.

Features:
Provides reliable and maintenance-free operation
Meets ASTM D409 standards

Included Items:
Hardgrove Grindability Tester (220V/50Hz)
Upper and lower grinding elements
8 Grinding Balls