Abstract: A vertical crusher having a housing defined chamber, enclosing a vertical axis rotor. The chamber has material(s) feed inlet(s) into the chamber. There is a drop-through outlet, which may be closable, from the chamber from which material(s) of at least a maximum size can drop in use. There are air inlet(s) into said chamber and air classifier outlet(s) from the chamber, for air or fine particles. Within the chamber also is a mass of discrete media, agitatable under the direct and/or indirect action of the rotor.

Abstract: The present invention relates to a control system for a rock crusher which is adapted for use with Vertical Shaft Impact rock crusher which divides the rock it processes into a stream which is supplied to a central rotor and a stream which cascades past the rotor. The control system is used to control the ratio of material placed into the cascade and includes a processing means which is adapted to receive a throughput signal from at least one throughput sensor. The processing means is adapted to transmit at least one control signal to at least one control mechanism of the crasher, and at least one control signal or signals are transmitted to said control mechanism or mechanisms to adjust the amount of material entering the crusher rotor to provide a specific cascade ratio for the crusher in response to a variable throughput of material.