Fine Grinders

Prater Fine Grinders (M Series Mills) are specially designed and built to grind free-flowing materials as fine as 400 mesh (37 microns) and produce uniform, narrow particle size distributions. Our highly efficient design permits ease of access to all internal components: one bolt allows for quick removal of the rotor.

Prater Fine Grinding Mills come in six standard sizes, ranging from the 3 HP M-19 pilot-scale lab mill to the 300 HP M-101 model.

All Prater Fine Grinders are designed with standard safety features, including a trapped key door safety interlock system that prevents unintended access to internal rotating parts during operation.

Prater Fine Grinders are designed and precision-built for maximum operational efficiency and years of trouble-free operation.

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Important features of Prater Fine Grinders include:

• Durable, welded carbon steel or stainless steel construction
• Simple, single-stage grinding for most dry, free-flowing materials
• Precision tolerances between rotor blade and grinding jaw or screen for uniform  size-reduction
• Large screen-to-horsepower ratio ensures maximum capacity for each model
• Interchangeable screen & jaw combinations for more versatility
• Large access door and streamlined interior for easy cleaning and maintenance
• Grinding blades, screens and jaws designed for easy replacement with minimal tools

• Outboard mounted spindle with high-grade labyrinth seals for maximum bearing life
• Standard-shaft grounding brush mitigates against internal electrostatic discharge
• Optional bearing monitoring package to complement existing predictive maintenance programs
• Ten-Bar shock-pressure-resistant construction available
• Sanitary construction features available

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Prater Fine Grinders operate on the principle of high-speed impact. Raw material is meter-fed into the center of the mill where rotor blades impact individual particles. Material is accelerated outward, creating more impact and shear across the face of stationary jaws and screens. These stationary surfaces also decelerate the particles, maximizing their impact speed differential as they rebound back into the rotor blade’s path. When the particles are properly sized they are pulled through the screen apertures for transport to the next stage in the process.

The accompanying schematic illustrates how Prater Fine Grinding Mills, which are typically integrated with a pneumatic conveying system, can be integrated into your operational workflow:

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