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All Impact Type Crushing Machines Use Speed to Crush!!

While there are many factors that affect the crushing efficiency of impact crushers, the most important of these is material velocity. This determines the amount of crushing which is done and the overall grading of the crusher discharge. Generally, the faster the material is accelerated, the greater the amount of crushing that is achieved. For this reason, it is essential that the impact crusher used have a wide operating speed range to accommodate a broad spectrum of material types and feed gradings.

REMco vertical shaft impact crushers have the broadest operating range of all VSI crushers. Please refer to the rotor velocity scale chart. For material reduction, the general velocity range is for particles traveling from 100 feet per second (30 MPS) to 325 feet per second (100 MPS). These are:

Shaping Speed – 100 to 175 feet per second (30 MPS to 53 MPS). At this speed tumbling, rubbing and mild impacts shape the stone. Soft material can often be reduced at these lower speeds which produce superior aggregate shape in all particles feed to the crusher. Very hard rock may only be mildly cubed at these speeds.   

General Crushing Speed – 175 to 250 feet per second (53 MPS to 75 MPS). This is the crushing range for producing typical aggregate products for construction materials. Severe impact, high attrition and compression of the rock stream cause particle failure. This results in a significant production of smaller particles when compared to those being feed to the crusher. Usually it is best to experiment with speed within this range because the fracture characteristics of rock vary widely. To get good crushing with a balance of recycle load and controlled production of fines, it is only necessary to achieve the threshold speed of fracture and additional speed consumes extra power rising energy cost and often generating undesirable size distribution in the crusher discharge.

Fine Grinding and Pulverizing – 250 to 325 feet per second (75 MPS to 100 MPS). Speeds about 250 feet per second are reserved for application where pulverizing and grinding of the material is desired. At these higher speeds, it is possible to produce manufactured sand and many industrial minerals products requiring fine sizes, in many cases smaller than 1 millimeter. These application require care, technical knowledge of processing and experience in good processing circuit design. This way the highest production of the needed fine product can be achieved without excess energy consumption and with acceptable overall operating cost.

Whether your crushing requirement is for shaping, general crushing or grinding and pulverizing, a REMco VSI can be custom applied to produce your product. Contact REMco for guidance.

How is speed applied to a REMco VSI?

REMco VSI crushers use a rotating impeller that acts as a rock pump to accelerate and impart speed onto the rock particles which are fed to it. Depending on the model and particular application, the rotor configuration and geometry can be varied to suit. A common feature of all REMco rotors is their unique internal construction, using the most efficient port configuration to accelerate the incoming feed stream into multiple flows.

As the rocks are fed to the crusher, each particle experiences a rapid acceleration and deceleration in microseconds. This fills the crushing chamber with a violent rock cloud. Depending on the desired product, the crushing forces applied can be controlled by the operating speed of the machine. This speed control when combined with a variety of crushing chamber features results in optimum crushing efficiency for the power employed.

Hard rocks may only be shaped at crushing speeds and soft rocks can often be crushed at shaping speeds.

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