The Operation, Typical Uses and Main Benefits of Impact Crushers
Since humans first started to build permanent dwellings and experiment with alchemy and new methods of preparing food, there has been a need for equipment capable of reducing large lumps of material of varying degrees of hardness to produce smaller and more manageable particles and, on occasions, even to reduce them to a fine powder. For example, colourful minerals were frequently ground to a powder by members of ancient civilisations such as the Egyptians, who used them to prepare the pigments used to dye clothing or perhaps as the basis of paint for writing and decorative art. Similarly, it was, and still is in many parts of the world, the practice for village women to pound corn or wheat in order to reduce it to the consistency of flour.
Today, when flour may be purchased from supermarkets, pepper mills, garlic presses, coffee grinders, and even the old-fashioned pestle and mortar are still used for various domestic purposes while industry is heavily reliant on such actions on a far larger scale, instead employing impact crushers and similar heavy machinery to provide the necessary force rather than muscle power. In fact, the alternative operational principles that are employed by these machines closely parallel those used to operate a simple pestle and mortar which may be employed in one of two ways. Using a rotary action, it applies an even pressure to the contents, which serves to reduce it to a powder that becomes finer as the rotary pressure persists. Alternatively, when it is necessary to break down larger lumps, one may first apply a pounding action in order to reduce them to a more manageable size before proceeding with the grinding stage if this is required.
It is this same pounding action that is employed by impact crushers. By contrast, the motive force upon which crushing machines that rely on the use of cones or jaw assemblies for their action is predominately pressure, while any impaction effect is minimal. Their action more closely resembles that of the coffee grinder and pepper mill or garlic press, respectively.
The impaction process offers a number of advantages over the alternatives, of which the first one is that it results in a more regularly shaped and uniformly sized end product that makes for easier handling. While the process may not be best suited to use on extremely hard materials, it is, nevertheless, capable of achieving significantly higher reduction ratios than when relying on applied pressure for the same purpose. Providing typical ratios of between 10:1 and 20:1 depending upon the material being impacted, this far exceeds the capability of cone and jaw devices that only offer a best performance in the region of 6:1.
These machines are invaluable in the mining industry where crushing is the first step in the processing of ore. Both impact crushers and alternative devices may be used sequentially in a number of steps until the resulting particles are of the required final diameter. Impaction may be applied by either a vertical or horizontal shaft with the latter limited to softer and less-abrasive materials such as limestone.
Kanu Equipment is a South African supplier of crushing equipment for use in mining, quarrying, construction, and recycling.
