2.7.4 Roll Sizer Crusher
Basic concept of the sizer is use of two rotors with large teeth on small diameter
shaft, driven at very low speed by a high torque driven motor. It is very useful
for the sticky and low hard limestone. The low height of the crusher allows
installing or replacing in existing plant. Crushing forces are completely
absorbed by the crusher housing. Very low fine generation is there due to low
speed crushing. It reduces the dust generation compared to other crushing
methods. The sizer crushes the input material between the crushing teeth
in the middle of the crushing chamber. The required shear and tensile
forces are generated by high rotor torques at low circumferential speeds.
Similar to a Wobbler feeder fines can pass between the crushing rolls with-out
being crushed any further. Therefore, the specific power consumption, the wear
rate, and the fines content in the crushed product are considerably lower
compared to other crushers.
As the height of the crusher is low, the civil cost of the building is low as
compared to impact crusher. The below table shows the brief comparison
between the impact crusher and Roll irrespective to their applications. Due to
low crushing ratio, it is used in primary and secondary crushing stage to get final
product size.
Figure - 6