For sale with its 8 inch by 3 inch rolls, the 911MPERC8C is the finest laboratory double roll crusher China has. It is massive and of top quality! Crushing by the Double-Roll Crusher is primarily accomplished by compression and consist of two heavy metal rolls of equal diameter placed horizontally which are rotated towards each other at same or at different speeds. The rolls are mounted on heavy shafts. One of the rolls is motor driven while the other roll rotates due to friction. The gap between the two rolls is adjustable because of two reasons—the product size is determined by the size of the gap between the rolls and to compensate for wear.
The rolls have narrow faces and are large in diameter so that they can squeeze sharply (nip) the large lumps. The roll surfaces of the Double-Roll Crusher are smooth. The materials to be crushed are fed from the top. As the rolls rotate they are nipped between them and get crushed by compression, and are discharged from the bottom. Compression crushing is extremely efficient, as energy is only used to crush those particles larger than the gap between the rolls. Fines are minimised because already crushed materials pass freely through the crusher with no further size reduction. The speed of rolls can vary but is fixed on this model. These machines give a reduction ratio of 4 to 1 with few fines. The double-roll crushers accept feed sizes up to 10 mm, though larger feed can be effectively handled in certain applications. The machine is protected against damage due to unbreakable materials like nut or bolts, by spring mounting at least one of the rolls. It retracts instantly when an unbreakable is encountered, then reverts to its original position once the unbreakable passes through the crushing chamber with no stoppage of the crusher. 
Advantages of this double roll crusher:
- Efficient for crushing of materials with moisture content less than 15%;
- Even final particles, no flaky and sticky materials;
- Excellent design and easy operation.
