A vertical shaft impactor (VSI) crusher is designed to produce high quality manufactured sand with a consistent shape and gradation and is particularly useful for quarries aiming to meet the rising demand for manufactured sand.

Pilot Crushtec highlights its range of VSI’s with an installed power from 45 kW up to 315 kW that can cater for production capacity needs of up to 300 tons per hour. Its 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.

Traditionally, cone crushers have always been the most preferred crushing solution in sand making, says Pilot Crushtec Africa sales manager Wayne Warren. 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 owing 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,”  he explains.

The VSI’s rock-on-rock crushing principle is said to be 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 a 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.”

Pilot Crushtec sales manager Charl Marais says a VSI’s ability to achieve constant product grading makes it ideal for sand making purposes.