Automatic Control of Impact Crushers Based On Visual Measurement of Size Distribution

This paper describes a practical implementation of a control scheme for two impact crushers operating in parallel as secondary stage crushers in a large-scale aggregate production plant in the United Kingdom. The control is based on measuring crusher power draw, mass flows and the size distribution of produced rock. The size distribution is estimated using image analysis. The settings, i.e. rotor speed and impact plate gaps, of the impact crushers are then automatically adjusted to produce the desired end products. The system compensates for crusher blow bar wear and changes in feed material properties.This is the first time that such a control scheme has been implemented in a production plant. This paper describes the methods and controls used as well as future developments including an optimizing control based on a second, already installed camera.Unfortunately the plant in question has lately experienced equipment breakages so an analysis of the observed benefits is not available in time for paper preparation deadlines. Such an analysis can be presented at the conference, however.