A rotary airlock feeder is a type of industrial valve used in material handling systems to process and transfer dry bulk materials for production. Though referred to by more than one name—rotary valves, rotary feeders, rotary airlocks, or simply airlocks—it is typically used to transfer solid bulk material from hoppers, bins or cyclones, into vacuum and pressurized pneumatic conveying systems. Its main components are the outer housing, rotor and shaft, end plates, a drive, shaft packing seals and bearings.

Rotary Airlock Feeders are valves that prevent the loss of air while transferring dry bulk solids at a controlled rate of displacement. . Though not one-hundred percent airtight, they are precision built, therefore can meter the flow of materials  with minimal loss of air. Thus, rotary airlock feeders are instrumental in bulk material processing by providing a controlled feed rate while  minimizing air leakage between pneumatic system components.

Rotary Airlocks are Not Simply Rotary Feeders

Though one and the same product, not all rotary feeders function as an airlock. The distinction is related to function and its function determines the words used to describe it: 

  • A feeder is a device used to transfer bulk solids from one chamber to another, often at a controlled rate of displacement
  • An airlock is a valve used to maintain air pressure differential between two distinct atmospheres

Therefore, a rotary feeder manages  the flow rate of a product whereas an airlock also provides a sealing function by separating the differential pressure between a bulk storage hopper and pneumatic conveying line while allowing material to move from one chamber to another in a controlled manner. 

Rotary airlock feeder applications range from use on silos, industrial cyclones and dust collectors that are used in conjunction with pneumatic conveying systems. In general, material is introduced into the valve from a hopper, and then processed through a multi-vane rotor which delivers the material into a pneumatic conveyor system with minimal loss of air pressure. Though a rather simple mechanical device, rotary airlock feeders are critical components in the efficiency of pneumatic conveying systems. 

Common Rotary Airlock Feeder Industries

Rotary airlock feeders are integral to a wide variety of industrial and agricultural material handling systems, whether in bulk solids or specialty products. They are utilized in any industry that processes dry free-flowing powders, granules, crystals, or pellets. They are also used as pollution control devices in industries processing wood, grain, food, textile, paper, tobacco, rubber, and paint products. Industrial use includes food and chemical processing, pharmaceutical manufacturing, plastics manufacturing, sanitary processing applications and processing of abrasive products.

Prater Industries is a global leader in the design and manufacture of rotary airlock feeders. Prater’s custom-built valves are designed to minimize pressure loss, are safe, reliable and will improve the efficiency of feeding and airlock operations compared to other rotary valve systems. 

High-Quality Rotary Airlocks 

Prater offers the highest quality rotary airlock products with many options to choose from. The general use Dust Collector (DCS) Series Rotary Airlock is an economical, budget-friendly choice for use under dust collectors, cyclones and hoppers. In handling dry, free-flowing powders where a pressure differential exists, the Heavy-Duty (PAV) Series Rotary Airlock would be an ideal choice. For higher degree of access to the valve internals the Quick-Take-Apart (QTA) Series Rotary Airlock was specifically designed for applications requiring frequent cleaning. The Quick-Take-Apart with Rails (BAV) Series allows for effortless removal of the demountable rotors and quick reassembly to maximize up-time. For high abrasive applications, the long-lasting, most durable rotary valve is the Abrasion Resistant Rotary Airlock. Lastly, Prater’s Blow-Thru Rotary Airlock Feeders are designed for applications requiring discharging sluggish flowing material into a pneumatic conveying line. 



Rotary airlock feeders are instrumental in processing bulk materials in many industries. Referred to by many names, rotary airlock feeders function as a valve in pneumatic conveying systems, on dust control equipment, and for volumetric feeding in critical applications.Prater offers a selection of custom-built rotary airlock feeders to meet the material handling requirements of a wide range of industrial and agricultural applications.