A rock crusher is a machine designed to break large rocks into a more manageable size. They can be used with any rock found in nature, or with man-made materials like reclaimed concrete. Rock crushers can be used to create gravel or rock dust, or simply to smash large rocks into smaller ones. The product created by rock crushers can be used for a variety of functions such as construction aggregates, landscaping, erosion control and more. Some crushers are stationary, but you can also get a portable rock crusher.
Rock crushers have a relatively simple function. Uncrushed rock is delivered into the hopper of the rock crusher by a dump truck, loader or other industrial transportation vehicle. A conveyor belt or sifting grid performs a preliminary screening, separating the rocks that don't need to be crushed out of the pile. From there, the remaining rocks are sent into the rock crusher, where they are broken down. Depending on the desired result, a single crusher may perform all the work, but in some cases, two, three or four rock crushers are used.
There are several different types of rock crushers. A jaw rock crusher consists of two slanted, ridged planes that slope down to create a funnel at the bottom – one jaw remains stationary while the other moves back and forth. Rocks too big to fit through funnel are smashed between the jaws until the smaller pieces fall.
Gyratory rock crushers are composed a series of descending gears that get smaller as they go down. Rocks get caught in the openings in the gears and crushed between them until they're small enough to go down to the smaller gears below, where the process is repeated.
Horizontal shaft impactors (HSI) simply smash the rocks between two large, swinging hammers. Vertical shaft impactors (VSI), use velocity as the primary breaking force, rather than the simple hard surface used by other crushers. These rock crushers essentially throw the rocks against an anvil. The velocity of the throw causes the rocks to break along their natural fissures. VSI is the most powerful type of crusher, able to do jobs that most other crushers cannot, and it also gives the resulting product a more uniform cube shape.