One Design, Many Applications
The basic design of the industrial hammer mill is really quite simple:
- A steel chamber containing a shaft to which rectangular steel hammers are affixed.
- Replaceable plates lining the mill’s interior to reduce wear caused from grinding abrasive materials.
- Steel screens or bar grates cover the mill’s discharge opening.
Similar, Yet Different
The same hammer mill for fishmeal and coal? Well, yes and no. The basic framework of the mill is the same. However, the configuration of the variable components is how they differ. That determination is based on the following criteria:
- Material being processed – Material characteristics such as: friability, flowability, moisture content, and in-feed size
- Desired finished particle size – Gravel, granules, powder?
- Desired production rate – 10 lbs/hr, 10 tph, etc.
With this information, the following can then be determined:
- Hammer mill size – Rotor diameters between 6″ and 44″, and internal mill widths of 6″ to 72″.
- Hammer size and style – Number of hammers, size, style and metallurgy.
- Screens or bar grates – Style and thickness of screen or bar grates, and size of openings.
- Choice of proper RPM
- How will the material be fed into the mill? By hand, auger, or belt conveyor?
- How will the material be taken from the mill? Heavy materials such as stone or metal may evacuate via gravity, while light or low density materials will require pneumatic suction.
- Is dust a concern?
Answers to these questions will help to determine the best types of optional equipment such as belt conveyors, augers, rotary feeders, and dust collection, as well as the most efficient design of the in-feed and discharge chutes.