Rotormills are sometimes referred to as long-gap mills, due to the lengthy ringed gap placed between where product enters and where it discharges. Able to enhance a material’s milled traits, these machines are used across a broad range of applications. Industries that use rotormills include the agricultural, chemical, energy, food processing, metallurgy, pharmaceutical, and waste management sectors.
Long Gap Design: How Rotormills Operate
Rotormills generate high turbulence, causing particles to collide at high speeds. An internal rotor within the grinding chamber helps pulverize the material. These machines have two sections: a lower and an upper section. The lower part acts as a fan, pushing material up to the upper part of the chamber, where it is finely ground.
Essentially, impact mills, rotor milling machines have a vertical shaft connecting both housing sections. Material enters the machine and is carried upward through the chamber by air moving from below. The setup keeps coarser particles in the chamber longer until they are finely ground.
In the upper section, grinding plates increase the speed of air and material as they strike the interior. Rotating air pockets help break down material, aided by particles colliding, while continuous airflow reduces internal heat.
Benefits of Rotor Milling Machines
Rotormills offer several advantages over other milling machinery. Their design enables the fine milling of a wide variety of bulk solids without the use of screens that are normally required to provide retention time to complete the grinding process in other technologies. In a Rotormill, residence time can be modulated to a degree using the speed of the conveyed air moving through it.
These machines can handle various products, including abrasive and hard-to-crush materials, reducing processing times and lowering costs. They are versatile, performing classification, size reduction, and conveying tasks while controlling the fineness of processed materials. Rotor milling machines are also effective for drying slurries from wet mills, with the suspension directly pumped into the grinding chamber.
Innovations in Rotor Milling Machine Technology
Over the past few decades, numerous innovations in rotor milling machines have made them more effective. These advances have improved their efficiency, flexibility, and performance.
Innovations of rotor milling machines has included:
- Energy-efficiency: Rotormills and other processing equipment are being increasingly engineered to optimize energy consumption and enhance motor effectiveness to lower operational costs.
- Modular design: Specialty rotor designs allow for easy replacement to enhance versatility; modular design will likely be used for other critical components.
- Noise reduction: Better rotor balancing helps minimize vibrations, and design improvements lead to quieter machinery and slower wear.
- Wear-resistance: Construction materials and coatings for rotor milling machines help extend the life of blades and rotors, especially when it comes to processing of abrasive materials.
Applications for Rotormills
Rotormills are versatile tools that reduce various materials into fine powders. They handle fibrous, hard, soft, and temperature-sensitive materials for many applications. Common materials include activated charcoal, fertilizers, plant matter, plastics, powder coatings, seeds, straw, tobacco, wood, and more.
Rotor milling machines can be used in various processing applications, including:
- Agriculture: Providing consistency to ingredients and additives in animal feed to promote consistency.
- Chemicals: Breaking down chemical powders used to produce fertilizers and resins.
- Cosmetics: Reducing ingredients for personal care products into powders.
- Food processing: Milling ingredients like grains, spices, and sugar to ensure better consistency.
- Metal powders: Finely reducing metals into powders.
- Minerals: Crushing minerals like coal, gypsum, limestone, quartz, silica, and talc.
- Paints and pigments: Crushing colorants into fine powers.
- Pharmaceuticals: Grinding active and inactive ingredients into powders for capsules, emulsions, tablets, and other medicines.
- Plastics: Reducing the size of plastic pellets used for producing plastic products and parts.
- Recycling: Reducing waste materials like plastics and elastomers.
Typically, rotormills can adapt to varying processes and speeds, while much of their electronic components are enclosed to keep them safe from dust permeation.
Rotor Milling Machines from Prater
The Rotormill is a rotor milling machine made and sold by Prater Industries. Initially designed by IPEC (International Process Equipment Company) and acquired by Prater in 2021, the signature Rotormill offers bulk processors a means to mill materials finely and continuously at high throughput rates. Prater’s iteration of rotor milling machines also works well with abrasive and more pliable materials. The Rotormill can also perform coating and mixing simultaneously, presenting processors with greater flexibility.
All Rotormills feature compact yet heavy-duty construction, an adjustable intake port for air, and easy access to the interior to access parts easily. To learn more about Prater’s various Rotormill models of rotor milling machines, contact one of our sales representatives today.
