Control systems for improvement of cone crusher yield and operation

Gyratory and cone crushers are regaining interest and are becoming more frequently used in order to create more energy efficient comminution circuits. A typical example is found in coarse comminution circuits were HPGRs are used as a first milling stage. In this case the preparation of a suitable feed with a well-defined width of the particle size distribution and a controlled top size are of high importance. In turn, this emphasizes the importance of a stable and controlled operation of the preceding crushing stages. Control systems for cone and gyratory crushers were first introduced during the early 60ths. The common opinion is that if these systems are able to compensate for the wear of the crushing liners the production yield can be increased with 20-25%. Over the years these types of systems have been widely used but the theory behind the principles have not been thoroughly scientifically scrutinized and presented. Of special interest is the capability to protect the crushers from long term overloading commonly defined as fatigue. With developments in electronics and plant control the crusher control systems have become more refined over the years. Though, there are sometimes conflicting interests in the control strategies between process requirements and crusher protection. In the paper an overview of the challenges, opportunities and existing control systems for cone and gyratory crushers is presented. A requirement specification for a system that is possible to fully integrate into modern plant control systems is outlined.