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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Prater rotary sifters, sometimes referred to as Rotary Sieves or Rotary Screens, offer more throughput capacity per screen area than any other conventional screening and separation equipment. Our maintenance-friendly design allows large, quick-opening access doors to be easily installed, ensuring access to the sieve chamber and all internal working parts. Virtually no tools are required for screen frame assembly changes, and changing or replacing these screens takes only minutes.

Prater Rotary Sifter Case Studies

Prater Prater Rota-Sieves® are ideal for high capacity scalping of bulk raw materials, blends, and finished products where scalping or safety screening is required to remove foreign material (e.g., insects, plastic, or string). Simple design and light-weight parts make routine screen inspections a breeze, enhancing compliance with plant quality programs.

Prater Rota-Sieves® are also well suited for sifting and classifying a wide range of free-flowing bulk powders, granules, and agglomerates, and those containing higher fat or moisture content. Self-cleaning screen fabric makes the Rota-Sieve® capable of separations to 325 mesh without anti-blinding mechanisms.

Key Features and Benefits

  • Standard stainless steel body and hoppers w/ various internal construction options
  • Greater capacity per square inch of screen, more throughput in a smaller footprint
  • Three bearings for improved rotor support and less wear to shaft seals
  • Fully adjustable multi-paddle rotor for varied screening intensity
  • Rotor quickly removed for cleaning and service
  • Screens easily inspected in place or out of body
  • Adjustable screen frame for improved performance from a variety of screen fabrics
  • Easy access to all internal working parts
  • Quiet, dust-tight, vibration-free operation, no external guarding required
  • Optional patented Rota-Trap® for pre-screening larger foreign material
  • Optional quick clean designs with tool-less removal of internal parts
  • Optional sanitary finishes and construction
  • Options for compliance with USDA, FDA, BISSC, 3-A, and other U.S. and European regulators


Rotary Sifter: Theory of Operation

Prater Rota-Sieves® utilize centrifugal force to fluidize and accelerate particles toward the screen surface. The sifter inlet is fitted with an auger that moves material into the screening chamber, where rotor paddles accelerate the particles outward. Smaller particles (fines) pass through the screen apertures and discharge through a large hopper. Rotor paddles are pitched to advance coarse material to the end of the screen chamber. They are then expelled thru a bulk-head 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 prevents blinding.

Centrifugal Sifter:

Rotary Sifter

Our centrifugal sifters scalp products from 1/4 inch – 325 mesh and boasts ultra-high-throughput per square foot of cloth area. They are equipped with three-bearing shaft support, drilled for superior air purge, and a fully adjustable 4-paddle rotor. It is self-cleaning and easy to maintain, with tool-less screen change capabilities and simple access to all internal working parts.

Mini Sifter:

Mini Sifter

Our mini-sifter is an easily assembled and disassembled rotary sifter that is completely versatile and vibration-free. It’s high throughput, safety interlocked features and heavy-duty design make the mini-sifter flexible enough for lab applications and rugged enough to meet small production requirements.

Not Sure Which Machine You Need?

Try our Equipment Recommendation Tool: choose a unit of measurement and desired finish size, and we’ll determine which machine to use.


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