Impact Crushing Machine

In crushing terminology , impact refers to the sharp, instantaneous collision of one moving object against another . Both objects may be moving, such as a baseball bat connecting with a fast ball, or one object may be motionless, such as a rock being struck by hammer blows.

Impact Crusher

There are two variations of impact: gravity impact and dynamic impact. Coal dropped onto a hard surface such as a steel plate is an example of gravity impact. Gravity impact is most often used when it is necessary to separate two materials which have relatively different friability . The more friable material is broken, while the less friable material remains unbroken. Separation can then be done by screening. Material dropping in front of a moving hammer (both objects in motion), illustrates dynamic impact. When crushed by gravity impact, the free-falling material is momentarily stopped by the stationary object. But when crushed by dynamic impact, the material is unsupported and the forc e of impact accelerates movement of the reduced particles toward breaker blocks and/or other hammers.

Dynamic impact has definite advantages for the reduction of many materials and it is specified under the following conditions:

1. When a cubical particle is needed
2. When finished product must be well graded and must meet intermediate sizing specifications, as well as top and bottom specifications
3. When ores must be broken along natural cleavage lines in order to fre e and separate undesirable inclusions (such as mica in feldspars)
4. When materials are too hard and abrasive for hammer mills, but where jaw crushers cannot be used because of particle shape requirements, high moisture content or capacity