High Pressure Grinding Rolls consists of a pair of counter rotating rolls, one fixed and the other floating. The feed is introduced to the gap in between the rolls and is crushed by the mechanism of inter-particle breakage. The grinding force applied to the crushing zone is controlled by a hydro-pneumatic spring on the floating roll. Speeds of the rolls are also adjustable to obtain optimum grinding conditions.
High Pressure Grinding Rolls (HPGRs) is similar in principle to regular grinding rolls but material is subjected to much higher forces. HPGRs consists of a pair of counter rotating rolls, one fixed and the other floating. Material is fed between the rolls with the floating roll pressing against the material flow by means of hydraulic pressure in excess of 50 MPa. The resulting force causes the material to compact by inter particle breakage. Pressures and roll speeds are adjusted to obtain optimum grinding conditions. The roll faces are typically studded because of improved wear characteristics.