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Product Overview Crusher Models Technology Applications Brochures Request For Quote 
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In crushing, the useful or meaningful work is that expended to reduce the material to a given size. A number of theories have been expressed to define the relationship between work input and size reduction. Kick’s Law states that work done is proportional to the reduction in volume of particles, a theory which applies to the crushing of large particles. However, finer product sizes conform more closely to Rittinger’s Theory which concludes that work required is proportional to the new surface area formed, and inversely proportional to the product diameter. In any case, reduction ratio is not the only factor in determining power requirements. Nearly all crushing projects differ from one another in one or more aspects, and no hard and fast rule can be applied with regard to power consumption. However, through extensive experience in the field of mechanical reduction, some average values have been compiled regarding the power requirements of different types of crushers. Typical Horsepower Requirements It has been determined that a primary single roll crusher, reducing run of quarry medium-hard limestone to a 6" (150mm) product will require approximately 1/2 horsepower per ton per hour (HP per TPH). However, when crushing medium-hard bituminous coal to the same specifications, the power demand is only 1/12 HP per TPH. Even on the hardest materials, single rolls do not require more than one full HP per TPH and may demand as little as 1/25 HP per TPH. Coalpactors for preparing coking coal for coke ovens are fed with 3" (75mm) and under bituminous coal. The product usually desired is 80-85% minus 1/8" (3mm). For this service, 11/2 to 2 HP per TPH is normally required. In cement plants, where hammermills or impactors are used for secondary crushing of cement rock, the feed is approximately 6-10" (150 -250mm) and the product is a nominal 1/2" (12mm). This reduction needs 11/3 to 11/2 HP per net TPH. Impactors generally require approximately 1 HP per TPH (gross load) to drive them. This may be slightly increased if an extremely fast rotor speed is required. Granulators (ring hammermills) are most often used in the coal handling facilities of power stations where they reduce run of mine coal to a nominal 3/4" (19mm) product. This typically requires 1/2 HP per TPH. The Pennsylvania Jaw Crusher requires approximately 1/3 or less HP per TPH, depending upon the reduction ratio desired. Bradford Breakers and Bradford Hammermills require approximately 1/4 or less HP per TPH. Motor Selection The foregoing figures are averages, and each crushing problem should be carefully studied before selecting motors. All prospective customers are urged to consult Pennsylvania Crusher prior to selecting motors, since so many factors will affect power demand. PCC's experience with such diverse types of crushers will serve as a guide for proper motor selection. Learn more... More on Size Reduction Methods | Crushing Tests | Product Screen Analysis (PDF) Home | Size Reduction | Feeders | Rep Finder | Parts Department Visit these other K-Tron Websites Pennsylvania Crusher Corporation |
