A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, or rock dust. It is used in many industries for the same above application suiting to requirements.
There are various types of crushers which can be used depending on investment, output desired, and many other factors. Only some of them are listed below.
A jaw crusher uses compressive force for breaking of particle. This mechanical pressure is achieved by the two jaws of the crusher of which one is fixed while the other reciprocates. A jaw or toggle crusher consists of a set of vertical jaws, one jaw is kept stationary and is called a fixed jaw while the other jaw, called a swing jaw, moves back and forth relative to it, by a cam or pitman mechanism, acting like a class II lever or a nutcracker. The volume or cavity between the two jaws is called the crushing chamber.
The jaws are fitted with Jaw plates, made from wear resistant various grades of Mn Steel for a longer life.
Cone/ Gyratory Crushers
A gyratory crusher is similar in basic concept to a jaw crusher, consisting of a concave surface and a conical head; both surfaces are typically lined with manganese steel surfaces. The inner cone has a slight circular movement, but does not rotate; the movement is generated by an eccentric arrangement. As with the jaw crusher, material travels downward between the two surfaces being progressively crushed until it is small enough to fall out through the gap between the two surfaces.
A cone crusher is similar in operation to a gyratory crusher, with less steepness in the crushing chamber and more of a parallel zone between crushing zones.
Impact crushers involve the use of impact rather than pressure to crush material. The material is contained within a cage, with openings on the bottom, end, or side of the desired size to allow pulverized material to escape. There are two types of impact crushers: horizontal shaft impactor and vertical shaft impactor.
Horizontal Shaft Impactor (HSI) / Hammer Mill
The HSI crushers break rock by impacting the rock with hammers that are fixed upon the outer edge of a spinning rotor.
Vertical Shaft Impactor (VSI)
VSI crushers use a different approach involving a high speed rotor with wear resistant tips and a crushing chamber designed to ‘throw’ the rock against. The VSI crushers utilize velocity rather than surface force as the predominant force to break rock.
More and more developments have taken place for various modifications of Impact Mills to suit specific applications, and the resulting crushers have been given new nomenclatures.
The selection of crushers for cement plant should take into consideration the following factors, namely, raw material’s hardness (generally represented by the compressive strength), corrosively (usually described with free quartz content), and viscosity (water content, and clay content).