They are called rotary valves, rotary airlocks, rotary feeders, rotary airlock feeders, or sometimes just airlocks. Though they can be called by many names, they are basically all the same components, used to transfer solid bulk materials from holding containers into conveying systems. 

Rotary Valves: A Difference in Use 

Rotary valves are a type of industrial valve consisting of a housing, shaft, rotor, shaft seals, end plates, bearings, and a drive. Most often, they are just referred to as rotary valves. However, what they are called really depends on their function. The components interconnected with rotary valves make them airlocks or feeders, though sometimes they are used for both purposes in the same application. 

Rotary airlocks maintain a pressure differential between two separate, differently pressured atmospheres, whereas feeders are used specifically for transferring bulk solids from one compartment to another, often doing so at a controlled rate. Though rotary valves look basically the same, the application and industry will determine what options or sizes work best. 

Rotary Airlock Functions

Rotary airlocks displace bulk solids from one vessel or atmosphere to another while minimizing the loss of air pressure between them. In pneumatic conveying systems, rotary airlocks are used to charge bulk solids into the system or to remove them from collection devices (e.g. cyclone or dust collector) at the end of a system. Pneumatic systems use high-pressure fans or blowers to impart velocity to air thru a defined circuit of piping, carrying the bulk solids with it thru the system. 

Rotary Feeder Functions

Rotary feeders manage flow rates of bulk solid products. They typically control the rate of displacement of product from a mass storage vessel to downstream process equipment where a controlled, consistent flow is desired. Used simply as a feeder, they do not separate atmospheres at different pressures. 

Rotary Airlock Feeder Functions & Applications

When used as an airlock and feeder, rotary valves are typically referred to as “rotary airlock feeders.” They prevent air loss while displacing bulk solids, such as when transferring product from a mass storage bin into or out of a pneumatic circuit. While airtight, rotary airlock feeders are built with precision tolerances to limit air loss in pneumatic circuits. In a sense, a rotary valve that works as both an airlock and feeder is like a revolving door, allowing the material to pass through it while maintaining air pressure within the building. 

Rotary valves are used as feeders, airlocks, or both for the following applications:

  • Agricultural sector
  • Asphalt production
  • Baking industry
  • Biomass processing
  • Cement industry 
  • Chemical processing
  • Coal industry
  • Dairy industry
  • Energy production
  • Food processing
  • Foundries and other facilities that work with metals
  • Handling aggregates 
  • Milling grains
  • Mineral processing
  • Mining sector
  • Paint industry
  • Pet food processing
  • Pharmaceutical manufacturing
  • Plastics fabrication
  • Powder coating production
  • Processes that turn waste into energy
  • Processing of wood products
  • Rubber fabrication
  • Steel fabrication
  • Textile industry
  • Tobacco industry

Rotary valves are essential parts of material handling systems, helping to process dry particles that can flow freely, whether in the form of crystals, granules, pellets, or powders. 

Prater’s Rotary Valves

Prater Industries provides numerous rotary valves, our design varies according to the industry or application for which they are used. 

Prater’s rotary valves include: 

  • Abrasion-resistant rotary airlock valves handle highly corrosive and abrasive materials well. As the most durable and wear-resistant rotary valve currently available on the market, its precision tolerances offer high-performance capabilities, along with a reduced need for maintenance.
  • BAV rotary airlock valves are ideal for applications that require frequent removal or maintenance of internal components. This rotary valve’s design includes a simple means of uncoupling the rotor and drive plus a rail system for extraction of the rotor for cleaning, inspection, and maintenance design also eliminates the need to gap the rotor during reassembly, help prevent operator strain or injury, and to protect components from damage due to misalignment.
  • Blow-thru rotary airlock valves work well for free-flowing materials and are specifically designed for production that requires releasing material into pneumatic conveyancing systems. Their innovative design allows these rotary valves to operate at lower speeds, handle 50 percent greater volume, minimize air leakage, boost efficiency and reduce wear.
  • Dust collector series rotary valves are designed specifically for material discharge from nuisance dust collectors. Economically priced, they provide basic air-sealing capabilities, work well in low-temperature environments with minimal pressure, and are easily configured.
  • Heavy-duty PAV series rotary valves offer a robust and versatile way to displace dry powdered materials and enable their free flow from bulk storage vessels into pneumatic systems. These rotary valves can be built for high-temperature environments and work well for abrasive and corrosive materials. 
  • QTA series rotary airlocks are designed for applications that require frequent removal of the rotary valve’s internal parts, facilitating cleaning and maintenance, though its lack of a rail system makes it a better choice when space is an issue. This rotary valve also allows the rotor and endplate to be removed as a single piece without tools while eliminating the need to gap the rotor during reassembly. 

Prater’s diverse line of rotary valves enables manufacturers to meet even the most challenging needs when it comes to bulk material handling and processing, ensuring low maintenance, optimal production, and reliable operations. With unique, cutting-edge, and customizable designs, Prater’s rotary valves can handle nearly limitless applications for any manufacturer’s bulk dry processing needs.