Hammer mills and lump breakers, also known as lump crushers, are machines used in material handling systems across a wide range of applications. Many industrial sectors require particle size reduction for the processing of material—minerals and mining, cosmetics and pharmaceuticals, agricultural and food manufacturing, pet foods and plastics, and so on. In processing material, particle size reduction may be necessary to increase the surface area of material, increase dissolution or absorption rates, improve pneumatic conveyance, achieve greater uniformity, or to provide effective drying and mixing of the material.

Though both lump breakers and hammer mills provide solutions for particle size reduction of materials, each is designed to fulfill different application requirements. This relates to the concept of size reduction, which varies depending on the processing needs of the material itself. Even though the common denominator is the reduction in size—the crushing, grinding, pulverizing, shredding, de-lumping, or milling of material is accomplished by utilizing specific equipment that emphasizes a unique mechanism to break the product into smaller pieces.

How each Machine processes materials

There are key differences with the application of lump breakers and hammer mills. Depending on processing needs, one may be more efficient or more economical than the other. To understand the differences between the two, let’s take a closer look at what each is and how they work. 

Lump Breakers

Lump breakers are used to break apart granules and powders that have agglomerated or formed lumps as the result of weak cohesive forces between individual particles. Lump breakers crush these lumps with specially shaped blades housed within its housing. The rotation of these blades through stationary, fixed combs applies sufficient impact and compression force to efficiently break lumps of agglomerated material fed through an opening in the top of the unit. The process continues until the material is reduced in size sufficient to pass through a screen at the discharge of the unit. 

Lump breakers are important in processing materials that tend to agglomerate and clump together during storage or transportation. This is common to cement, fertilizers, and powdered chemicals found in heavy industries, but also foodstuffs like sugar, salts, food casings, and granola bars. In fact, any type of dry, granulated, fine, or powdered material that has a tendency to absorb moisture resulting from humidity will likely become lumped when stored. Lump breaking the material into its original, uniform particle size allows for easier handling and further processing. 

Hammer mills

Unlike a lump breaker, a hammer mill is designed to crush, grind, pulverize, and shatter individual particles of solid material.  Uniform particle size reduction of raw material occurs via repeated blows by moving hammers attached to a rotating shaft housed inside the mill’s chamber. Once material is fed into the chamber, the swinging hammers impact and accelerate the particles, where they collide against the chamber walls and against each other. Repeated impact and collisions will occur until the individual particles are small enough to pass through a screen located at the bottom of the chamber.

Whether pepper, coffee beans, coal or asphalt, hammer mills can effectively shatter, grind, shred, crush or pulverize any raw material to a desired outcome through repeated impact. The resulting particle size is not only determined by screen size, but also the hammer tip speed,  thickness and quantity of hammers, and their uniform configuration, or pattern as distributed around the circumference of the rotor.. For example, reducing stones to a fine size would require a high shaft speed with balanced symmetry, a smaller screen, and a high number of hammers.

Breaking Down the Difference Between Lump Breakers and Hammer Mills

As mentioned, lump breakers are designed to reduce agglomerated particles, whereas hammer mills are used to break down individual particles into smaller sizes. A lump breaker gently crushes and pulverizes fine material that has agglomerated or densified due to environmental conditions in the course of transportation or storage.  A hammer mill operates with extreme power, efficiency and higher impact force to reduce bulk solids to a uniform particle size. 

Lump breakers and hammer mills are each used for particle reduction of material. Both are robust machines that are utilized to process large materials into smaller materials for easier handling and further processing. However, they function in different ways. The key difference between them is related to their respective application methods which in turn, is related to the type of material being processed. Whether the material requires the gentle impact of a blade or the forceful impact of a hammer will determine which application, the lump breaker or hammer mill, is best suited for the processing requirements of the material.