Generally speaking, whether the impact crusher is vertical shaft (VSI) or horizontal shaft (HSI), the main difference from the cone crusher is the type of crushing force. Impact crushers crush material by striking it against another object. Cone crushers use compression crushing to squeeze or compress material between two crushing surfaces.
The type of crusher and choice of crushing process for any application depends on material hardness, material density, feed size, desired product size and capacity as well as the initial cost per crusher and the cost of maintaining each crusher.
Basic structure and working principle
The horizontal shaft impact crusher consists of a hopper, two or three aprons, a rotor, blow rod or hammer. Basically, chunks of product are fed into a hopper where they come into contact with hammers or blow bars to a rotating rotor that breaks the material into smaller pieces. When the larger material is struck by the hammer, it makes contact with each apron, bouncing it back to the rotating hammer for another round of impact until it discharges the HSI.
The vertical shaft impact crusher consists of a feed hopper, a feed pipe, a rotor and a fixed anvil or rock frame. Essentially, the feed drips through the feed tube into the rotor, which centrifugally throws the material towards a fixed anvil made of composite metal alloy or rock (by installing a rock stand). When the rock hits the anvil or ledge, it breaks down along natural stress lines to form a uniform cubic product.
The cone crusher consists of a bowl liner, a sleeve, main shaft and frame, compression, eccentric inner and outer bearings. Essentially, by squeezing the material until it breaks, the size of the material is reduced. Specifically, the material is compressed between a moving sheet of steel (the mantle) and a stationary sheet of steel (the bowl liner). The final product size is determined by the closed gap between the bottom two crushing parts. When the cone rotates eccentrically, the material is crushed and works down through the crushing chamber until it is discharged at the bottom of the machine.
In order to understand the cone and impact crushing processes, it is essential to understand the material that will be crushed, which will determine the best crusher for your business needs. When considering the material to be shredded, you must consider abrasiveness, hardness, density, amount of fines and your desired finished particle shape.
Impact crushers are used to crush softer, lower density and abrasive materials such as limestone. Due to its consistent striking process, the impact crusher produces a uniform cubic finished product, which is ideal for hot asphalt producers. Depending on the application, impact crushers can have higher wear costs, higher maintenance, and produce more fines. Impact crushers can be used as primary, secondary or tertiary crushers, depending on the producer’s final product size requirements. These crushers are available in stationary, orbital and mobile designs. Another industrial use is slag, especially blast furnace slag, which is less abrasive than steel slag and can be broken down if processed through impact crushers.
Cone crushers are mainly used to crush harder, more abrasive and dense materials, such as granite, for construction, chemical, metallurgy and silicate industries. Cone crushers are available in primary, secondary and tertiary locations. These crushers are available in stationary, orbital and mobile designs. Cone crushers are also used in the steel slag industry, a much more abrasive slag than blast furnaces.
Impact crushers, initially, are less expensive than cone crushers. Although cone crushers are more expensive upfront, they will require much less maintenance than impact crushers. Much of the maintenance cost of an impact crusher comes from wear on the blower rod and apron, which can exceed the initial cost of a cone crusher if used to crush highly abrasive materials. As mentioned earlier, producers must understand their industry needs and the materials they will be mining in order to choose the best crusher.