Hammer Mill

Hammer Mill: A Complete Guide to Its Types, Applications, and Benefits

In order to process material in a physical state that is apt for a specific use, its size reduction is required in several industries, such as agriculture, food processing, pharmaceuticals, construction, and recycling. Although there are many machines to reduce materials to size, one of the most common and preferred are hammer mills because they work efficiently, are easy to operate and clean, and are a versatile piece of equipment. Hammer mills are a durable piece of equipment designed to pulverize, crush and grind materials into smaller and more uniform particles than were originally present in linear dimensions using high-speed rotating hammers attached to a string.

What is a Hammer Mill- Detailed Explanation

A hammer mill is a revolving machine with hammers that are usually mounted to a shaft and there are screens or perforated plates that allow for some size restriction. Once the shaft starts to rotate at high speed, the material is impacted with the hammers which grind it into smaller sizes. The particles can go through the screen or they stay in the chamber until the desired size is achieved.

A hammer mill can accommodate a wide variety of feed materials, from soft, friable materials to hard, fibrous ones. What ultimately affects the size of the particles produced is determined by rotor speed, size of hammers, and size of the screen openings.

Types of Hammer Mills

Hammer mills are classified in different types on the basis of their construction, application, or based on feed material. Here are the most common types:

• Gravity Discharge Hammer Mill: This is the simplest and most common form. The output relies on gravity to assist in discharging the processed material. It is best suited for relatively coarse grinding.
• Full Circle Screen Hammer Mill: This version of the hammer mill features a 360-degree screen area that increases the screen coverage and improves output per horsepower consumed, allowing for a finer grind.
• Industrial Hammer Mill (Heavy-Duty): This hammer mill is industrial strength due to pressure and commonly utilized if the grinding job involves high volumes and/or abrasive feed materials. These mills use heavy-duty components as a result of action to withstand the demands of the task.
• Laboratory Scale Hammer Mill: These mills are used for R&D and small-scale operations. Laboratory scale hammer mills have the same basic design as larger mills, just in a smaller configuration.
• Pneumatic Discharge Hammer Mill: In this application, air assists the grain particles of the discharged material out of the chamber instead of relying only on gravity. Pneumatic discharge has the advantage of relatively less screen wear, as the air carries ground particles out of the chamber, resulting in higher throughput.

Common Hammer Mill Applications

Hammer mills are truly versatile equipment used across many industries. Below are some of the most common applications:

• Agriculture and Animal Feed: Hammer mills are most commonly used for grinding grains, cereals, and other ingredients for animal feed such as corn, wheat, soybean meal, and barley. Taking the correct particle size is important for optimum digestion in animals.
• Food Processing: In food manufacturing markets, hammer mills are primarily used to process spices, sugar, salt, dehydrated vegetables, and herbs. Additionally, hammer mills offer uniformity of texture and quality assurance in the final product.
• Pharmaceutical & Nutraceutical Industry: In pharmaceutical manufacturing, small and large pharmaceutical companies are turning to hammer mills to size-reduce active pharmaceutical ingredients (API's), (excipients) to a consistent size before tableting or filling capsules. This type of milling machine is chosen due to the hygienic operation and control.
• Wood and Biomass: In the wood products and biomass sectors, hammer mills play an important role in grinding wood chips or sawdust and biomass into pellets or briquettes for renewable energy production.
• Chemical: In the chemical market, hammer mills have proven to be an effective equipment at reducing and grinding consistent fine powders of substances such as resins, pigments, fertilizers and detergents.

Benefits of Hammer Mills

Simple design and operation: A hammermill is mechanically simple and thus easy to operate and maintain.

Versatile: Hammer mills can process a wide variety of materials, soft/fibrous to hard/abrasive. Thus, they can be applied to many applications.

High production capacity: Hammer mills can hold large amounts of material in a relatively short period. This helps achieve high production rates, or through-put.

Economical: A hammer mill is a cost-efficient form of grinding.

Adjustable output: By changing the size of the screen or speed of the rotor, you can adjust the final particle size to suit your requirements.