Patent ID: 7360726

Claim:
Method for determining a start-up crushing gap width for a crushing operation in a gyratory crusher, the crusher comprising a crushing head fastened on a shaft and provided with first and second crushing shells arranged to form a crushing gap to receive material to be crushed, the width of the crushing gap being adjustable, and a driving device arranged to cause the crushing head to execute a gyratory pendulum movement, the method comprising the steps of: A. activating the driving device to cause the crushing head to initiate a gyratory pendulum movement, with the crushing gap set at a first start-up width; B. commencing a feed of material into the crushing gap to initiate crushing; C. measuring a load on the crusher resulting from the crushing; D. adjusting the width of the crushing gap to cause the load to approach a selected value, and obtaining a measure representative of the adjusted gap width; E. calculating a subsequent start-up width in accordance with the obtained measure of step D; and F. setting the width of the crushing gap to correspond to the calculated subsequent start-up width of step E prior to repeating step A for a subsequent crushing operation; wherein step B includes starting a countdown of a predetermined time period beginning with the start of the supply of material into the crushing gap; step D including determining whether the width adjustment has occurred within the predetermined time period; and step E being performed only if the width adjustment has occurred within the predetermined time period.