Rotary Sifters (Rotary Sieves)

Rotary sifters, rotary sieves, and rotary screens with more throughput capacity per screen area than other screening equipment on the market.
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SiftersThe Prater Rotary Sifter, or Rota-Sieve®, is designed for sieving operations in which bulk raw materials, blends, and finished products need scalping or sifting to remove foreign materials or particles such as plastics, strings, or insects. The simple design and lightweight parts of the Rota-Sieve make standard inspections an easy and straightforward process..

Our rota-sieves are also ideal for the sifting, scalping and classifying of a wide variety of particles and products, including:

  • Bulk, free-flowing powders
  • Granulated substances
  • Agglomerated materials

Our units are easy to maintain and designed for many years of maintenance-free life. Self-cleaning screen fabrics ensure that the Rota-Sieve® can separate to 200-mesh size without the need for anti-blinding mechanisms.

Important Features

Distinctive features of the Prater Rotary Sifter include:

  • Standard stainless steel body and hoppers with numerous internal construction options
  • Greater capacity relative to the size of the screen, providing more output using a smaller footprint than competitors
  • Three bearings for improved rotor support and minimal wear to shaft seals
  • Fully adjustable multi-paddle rotor for customized screening capability
  • Rapid-removal of rotor specially designed for quick cleaning and maintenance
  • Easily-inspected screens, either in place or when removed
  • Adjustable screen frame designed for improved performance from a variety of screen fabrics
  • Easy access to all internal working parts
  • Low-noise, dust-tight, vibration-free operation without the need for external guarding
  • Optional patented Rota-Trap® for pre-screening large-sized foreign materials
  • Optional quick-clean designs with tool-free removal of internal parts
  • Optional sanitary finishes and construction for specialty applications
  • Options for compliance with USDA, FDA, BISSC, 3-A, and other U.S. and European regulators

Operational Theory

Prater Rotary Sifters harness the power of centrifugal force to fluidize and accelerate particles toward the screen surface. The sifter inlet is specially fitted with an auger that moves materials into the screening chamber, where rotor paddles accelerate the particles outward. Finer particles pass through the screen and are discharged into a large hopper. Rotor paddles are precisely pitched to force coarser material to the end of the chamber, where they are expelled into a separate discharge hopper. Over-size and near-size particles interact with the screening surface during operation, causing a natural vibration in the fabric that enhances free flow.

 System Integration

The accompanying schematic drawings demonstrate how the Prater Rotary Sifter can be adapted to your current operational setup. Rotary centrifugal sifters can be utilized in a stand-alone process, after material silos, ahead of mixing operations, and prior to final packaging. In addition, they can be set-up as ‘in-line’ or ‘blow-through’ sifters with pneumatic conveying systems:

We are Here To Help

Let us know how we can help you with your sifting and classifying operations. We can customize our rotary sifter’s fabrication to fit the exact specifications required by your product line. If there are specific features not found in our standard rotary sifter, we will quickly develop the ideal solution for you. If you already own a Prater sifter or other product and need any attention whatsoever, please call us for immediate service.

Prater Rotary Sifter Case Studies


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