A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, or rock dust. Crusher or rock crusher is machine used to reduce the size of rocks and stones in construction material recycling applications, aggregates production and mining operations.
These machines are mostly used mining industry. Bigger parts are respectively crushed primary, intermediate and fine crushing stages. Each crusher is designed to work with a certain maximum size of raw material, and often delivers its output to a screening machine which sorts and directs the product for further processing.
In operation, the raw material (of various sizes) is usually delivered to the primary crusher’s hopper by dump trucks, excavators or wheeled front-end loaders. A feeder device such as an apron feeder, conveyor or vibrating grid controls the rate at which this material enters the crusher, and often contains a preliminary screening device which allows smaller material to bypass the crusher itself, thus improving efficiency. Primary crushing reduces the large pieces to a size which can be handled by the downstream machinery.
All rock crushers can be classified as falling into two main groups. Compressive crushers that press the material until it breaks, and impact crushers using the principle of quick impacts to crush the material. Jaw crushers, gyratory crushers, and cone operate according to the compression principle. Impact crushers, in turn, utilize the impact principle.
Jaw crusher is mainly used in primary crushing stage. Their main purpose is to reduce the material to a small enough size that it can be transported by conveyors to the next crushing stages.
Gyratory crusher is frequently used in the primary crushing stage and a little less often in the secondary stage.
Impact crusher is versatile crushing machine that can be used in any stage of the crushing process. However, the features and capabilities of different impact crusher types vary considerably.