A Vertical Shaft Impactor (VSI) operates using a spinning rotor mounted to a vertical axis shaft. The rotational speed of the rotor (into which rock is fed vertically) in conjunction with the machine configuration (Rock on Rock, Rock on Steel, or Steel on Steel – also known as Hammer & Anvil) determines the finished product particle size.
VSI crushers are often used in tertiary, or quaternary stages of the crushing circuit, although some may be used in secondary applications depending on the size and friability of the feed material and machine configuration. These styles of crushers are used in applications ranging from sand & aggregate production to mineral processing. In quarrying, for example, they are commonly used to produce cubical shaped aggregates ideal for concrete and asphalt applications, manufactured sand production as well as beefing up the fines content in the road base.