There are numerous industries that depend on particle size reduction to improve the performance of a variety of materials. Particle size reduction is utilized in the manufacture of many end products across a variety of industrial sectors.

The three most popular particle size reduction techniques on the market today are compression type mills (e.g. roller mills), impact mills (hammermills, fine grinders) and attrition mills (e.g. colloidal mills or disc grinders).The method of choice relates to the properties of the material being processed and its desired attributes following the size reduction process. For instance, a friable (brittle) material may respond better to impact milling whereas an attrition mill may be better suited for softer or heat sensitive materials. Compression type mills may be preferred for products that require gentler processing with less heat generation. 

Specifying Fine Grinders

Fine grinders fall under the category of impact milling equipment, a mechanical particle size reduction method used to decrease the fineness of most bulk solids. Impact mills  reduce the size of large particles by introducing a striking force that stresses the natural defects, or weak spots in those particles beyond their yield strength. Fine grinders are best suited to reduce dry, free-flowing, friable material into a narrow particle distribution defined by a series of mesh or micron sizes. While it's common to refer to a size objective using a single target size, specifying at least three can help better define the coarsest, median and finest particles desired. To avoid confusion, maintain consistency when referring to mesh and micron targets, as they can often be confused. While charts are available to convert one to the other, the two can be misinterpreted if not properly identified. For example, a client who desires an 80 micron result would misrepresent their goal by stating an 80 mesh (212 micron) objective.  

Benefits of Size Reduction

Size reduction carries several benefits. For example, smaller particles tend to exhibit more trait uniformity, whether it be color or grain texture, that can positively contribute to product perception. Particle size uniformity also prevents segregation of individual ingredients within a blend.  In another example, size reduction is utilized to increase the surface area of materials, which can enhance the color concentration of pigments or the reactivity of sorbents. In both cases, “less is more,” resulting in higher value of the ground product. Size reduction is also vital in the production of cereals and grains, whether it be for improving the functional properties of a flour or the digestibility of animal feed. 

Benefits of Prater Fine Grinders

Prater Industries’ Fine Grinders are designed to micronize free-flowing materials from 60 to 200 mesh (74 micron). Capable of running in an air sweep, they are also well-suited to process heat sensitive materials such as sugar or resin. Their precision design includes a close tolerance between the rotor blades and grinding jaws & screens, resulting in a uniform particle size distribution. A large horsepower to screen ratio provides greater efficiency. What sets Prater Fine Grinders apart is their unique inner workings.  Product is uniformly fed into the grinding chamber, where air sweeps particles into harm's way along the impact face of blades positioned around the rotor’s circumference. Impacted particles are accelerated outward, colliding with one another and shearing along the face of machined jaws and screens fixed around the outside of the rotor. The stationary surfaces of these jaws and screens cause rapid particle deceleration and rebound into the rotor’s path for additional impact. This process of impact, acceleration/deceleration, shear and rebound continues until particles are small enough to pass across the screens’ apertures. Selecting screens with different apertures helps define the endpoint of the grinding process, where smaller apertures create more retention of particles so additional work can be done. Pneumatic air helps to displace particles through the screen and conveys the ground product to a down-stream collection point. 

The overall benefits of the Prater fine grinders include greater capacity, better dust control, a precise distribution, easier maintenance, and improved standard safety features such as the automatic safety door interlock. The vertical rotor design with a large, hinged door of Prater’s fine grinder allows for easy access to the internals of the mill thus reducing maintenance and changeover times.

Prater Industries offers the highest-quality fine grinders to ensure efficiency and overall performance designed to meet every industrial processing need.