Other types of crushers work through compression where the material is pressed using compression force against two hard surfaces to reduce it to size. Impact crushers on the other hand operate through impact where the rocks and other materials are hit by a rapidly turning rotor. This method can be used for highly abrasive materials or for less abrasive materials like limestone, phosphate, gypsum and others. The impact crusher is usually caged with a hole that extrudes the pulverized materials. This is caging is done to ensure the materials do not fly around which can be dangerous to people.
There are two types of impact crushers; horizontal and vertical shaft.
Horizontal shaft impact crushers (HSI) – they have a horizontal rotating shaft that has hammers attached to the spinning rotor. The hammers are responsible for breaking the rocks. The horizontal alignment makes these impact crushers less effective and therefore they are suitable for soft materials like gypsum, phosphate and limestone. The materials produced after the crushing process are highly irregular since the hitting motion breaks them quite randomly.
Vertical shaft impact crusher (VSI) – they have a vertical rotating shaft. The vertical shaft impact crusher comes with a crushing chamber or the main chamber where the crushing occurs. The high speed rotor, throws the rocks to the crushing chamber walls made of wear resistant hard surfaces that break the rocks on impact. The process continues until the rocks are small enough to go through the discharge point.
The force of the vertical shaft impact crusher is determined by the speed of the rotating rotor. Vertical shaft impact crusher uses the velocity force that is applied evenly to the rock and the surface which therefore results to even and more cubicle shapes due to this kind of consistency. The vertical shaft impact crushers can be used for quite coarse materials and rocks since they are usually very high power and high efficiency. They are also highly durable and made to last for long.
Impact crushing can be categorized as dynamic or gravity crushing. Dynamic crushing is what happens in a horizontal shaft impact crusher. Gravity crushing can be imagined as what would happen when an item is dropped from a certain height to the floor and it breaks. This is precisely what happens in a vertical shaft impact crusher where the materials are thrown at high speeds to the surrounding hard crushing surfaces.
Over the years the impact crushers have become so well developed to make them highly effective at crushing materials. So many changes have been made to the impact crushers both in the VSI and HSI crushers which has enabled these crushers to now be able to handle more coarse materials and perform better. They can be able to produce a high tonnage per hour. With the increased efficiency, capacity and output, impact crushers are also become some of the main crushers you can find in many industries today.