MUNSON's HammerHead™ Hammer Mills reduce a broad range of friable, non-friable and fibrous materials into particle sizes from one inch (25.4 mm) down to 200 mesh, determined by friability of the material.
The high-shear/low-resistance cutting action of the hammer tips rotating at speeds up to 270 MPH, together with the rotational inertia of the heavy-weight rotor assembly, reduces higher volumes of materials and yields greater output per horsepower/kilowatt than other types of mills.
While hammer mills handle an exceptionally wide range of material types and sizes, they generally offer less control in terms of particle uniformity and fines production than do MUNSON® Pin Mills and MUNSON SCC Screen Classifying Cutters.
Centrifugal force causes pivoting hammers to stand at 90° to the rotating shaft, striking material in mid-air and smashing it at high speed against hardened breaker plate ridges until particles are sufficiently reduced to pass through a bed screen.
Particle sizes are determined by the friability of the material and the size of bedscreen perforations which range from 1/32 to 3 inch (0.8 to 76 mm).
The shaft assembly, which consists of a primary shaft, multiple discs and four secondary shafts with hammers and spacers, are driven at 1800 to 4000 RPM by a high horsepower motor.
Hammer tip speeds range from 17,000 ft/min (5182 m/min) for model 121, to 23,750 ft/min (7239 m/min) for model 141, reducing a broad variety of solid materials into particles at ultra-high rates, even under heavy loads.
The proprietary hammers, which are hardened by heat treating after machining, can be reversed end-to-end and side-to-side, allowing all four cutting edges to be utilized before being replaced. A removable pin, recessed within a hardened steel guard, allows rapid removal of the secondary shafts, hammers and spacers for servicing.
In addition, all corners of the hammers are stepped as standard, offering three-times the cutting edges of square-cut hammer tips for greater efficiency.
For general grinding, standard equipment consists of alternating heavy and light hammers. However, the type, number and arrangement of hammers can be varied readily to optimize performance according to material characteristics.
The unit is configured with a large safety-interlocked door, providing rapid, unobstructed access to the mill case interior.
The upper cylindrical breaker plates and lower bed screens slide within precision-machined channels, and are held captive by the unit's door when closed, providing secure, dust-tight operation as well as rapid removal of internals.
As standard, cylindrical breaker plates encircle the upper half of the mill chamber, while bed screens encircle the lower half. However, when greater throughput of easily-reduced materials is desired, a 90° section of breaker plate located below the hinged top section of the mill case can be substituted with a 90° cylindrical section of bed screen, increasing total screen area to 270°.
Material is fed through the infeed hopper at the top of the mill, while on-size particles exit through a lower flanged outlet, and are typically removed by a dilute-phase vacuum conveyor, or are gravity fed into a downstream process.
The heavy-gauge housing provides the stiffness required to maintain precise alignment, and withstand the extreme impact and high loads of the most demanding applications.
The rotor assembly, which is powered by a fully-guarded, direct-coupled drive, rides on sealed flange-block bearings mounted on a heavy-gauge fabricated and machined housing, providing vibration-free operation.
Carbon steel or stainless steel construction in a range of finishes is offered to satisfy virtually any industrial requirement.