Decreasing or closing the gap settings between the impact aprons and blow bars will give you an increased retention time in the chamber and ultimately lead to an increased reduction ratio. It is important to remember however it will also reduce the efficiency of the impactor. Closing the gap settings will result in your production dropping and your fines generation will increase.
Crushing is done by the energy being transferred from the rotor into the rock. 60% of the crushing is to be done between the rotor and the first apron. So holding the material in the chamber too long by reducing the gap settings may give you an upside in reduction but a downside in production.
Contact our technical team for more support on your crusher, screen or conveyor.