As quarries seek to meet the growing demand for manufactured sand, vertical shaft impact (VSI) crushers are proving to be the ultimate solution due to their ability to produce high-quality manufactured sand. With a rich heritage in the design and manufacture of VSI’s, Pilot Crushtec International (Pilot Crushtec) can cater for production requirements by using various size VSI’s with installed power from 45kW up to 315kW.
Traditionally, cone crushers have always been the most preferred crushing solution in sand making, says Wayne Warren, Africa Sales Manager at Pilot Crushtec. However, the downside is that for a cone crusher to produce sand, it needs to be set on a very tight closed side setting (CSS), which renders it uneconomical due to the resultant excessive wear.
“A very tight CSS means that the crusher works on a liner-on-material crushing concept, which is not ideal because the wear rate increases dramatically, and the shape is generally poor,” explains Warren.
The VSI’s rock-on-rock crushing principle is more efficient in producing manufactured sand as it directly crushes the rocks without any intermediate crushing stages. “The VSI makes use of material-on-material crushing – the stone is accelerated at high speed into a rock box of the same hardness material, resulting in maximum breakage of the feed material,” explains Warren. “Depending on the speed, this can accomplish two things: stone shaping with some sand generation or, on a higher speed, a higher percentage of sand.”
Charl Marais, Sales Manager at Pilot Crushtec, says a VSI’s ability to achieve constant product grading makes it the ultimate crusher for sand-making purposes. “If you feed a VSI constantly, it gives you a constant grading. On the contrary, with a cone crusher there is inconsistency in quality because of the way the liners wear. As soon as you have an uneven wear pattern on your mantle and bowl liners caused by intermittent feed conditions, your grading fails as well,” says Marais.
Pilot Crushtec’s VSI offering covers a broad range of kilowatt (kW) units in three shells, from 45 kW to 315 kW. The three base models comprise the VS100, VS200 and VS350, covering five different rotor diameters from 600 mm to 1 000 mm and 14 different configurations to suit differing customer needs.
