What Is a Rotary Valve and How Does It Work?

A rotary valve (rotary airlock) is a device with rotating pockets that discharges bulk solids such as flour, cement or dust at a controlled rate while acting as an airlock.

Main Functions

• Discharge material from silos or filters at a controlled rate
• Isolate pressure difference between a silo/filter and a pneumatic line
• Stabilize the capacity of the conveying system

Working Principle

1. Product fills the rotor pockets from the top inlet.
2. As the rotor turns, each filled pocket moves downward.
3. Material is discharged through the bottom outlet at nearly constant capacity.
4. Because the pockets are mostly filled, air leakage between inlet and outlet is very limited — providing an airlock.

Selection Criteria

• Material type and particle size
• Bulk density and moisture content
• Operating temperature
• Line pressure in the pneumatic system
• Required capacity (m³/h or t/h)
• Housing and rotor material (carbon steel, stainless, cast iron, etc.)

Typical Applications

• Dust filter outlets
• Silo discharging
• Pneumatic conveying systems
• Feeding of packaging or dosing lines

A properly selected and correctly driven rotary valve has a direct impact on the efficiency and reliability of your process.