Hammer mills are among the most widely used grinding mills and at the same time the oldest ones. They are actually crushers which can grind, pulverize, and crush a wide range of materials. It consists of a series of hammers usually four or more which are hinged on a central vertical or horizontal rotating shaft and enclosed within a rigid metal case. The hammers are free to swing on the ends of the cross, or fixed to the central rotor. The rotor is spun at a high speed inside the drum while material is fed into a feed hopper. The material is impacted by the hammer bars and is thereby shredded and expelled through screens in the drum of a selected size.
Hammer mills crush materials in two stages:
- Size reduction which occurs by dynamic impact
- Sizing which occurs by attrition and shear in the second zone where small clearance exists between the hammer and the screen bar producing a particle range of 15-50 µm.
The targeted particle size can be controlled through feed rate, rotor speed/ velocity, hit resistance, size of screen opening (determines the residual time of the material) and clearance between the hammer’s and grinding plates.
Kani Sanat is popular as the industrial machinery expert for over 20
years. We’ve earned our reputation on manufacturing high quality, heavy-duty processing equipment, including custom hammer mills for size reduction.