What Is a Roots Blower?
A Roots blower, also called a lobe blower or positive displacement blower, is a type of compressor that moves a fixed volume of air with each rotation of its twin lobes. Unlike centrifugal fans, a Roots blower delivers constant airflow regardless of back pressure — making it ideal for applications that demand reliability.
The design was patented by Philander and Francis Roots in 1860 and has remained a workhorse in water treatment, pneumatic conveying, and industrial vacuum systems ever since.
How Does a Roots Blower Work?
The blower contains two figure-8 shaped rotors (lobes) that spin in opposite directions inside a closely fitting housing. As the lobes rotate, they trap air between the rotor and the casing, then push it towards the discharge port. No internal compression takes place inside the blower — the compression occurs externally when the discharged air meets the back pressure of the system.
This simple mechanism means Roots blowers have very few wearing parts and require minimal maintenance.
Key Applications
- Wastewater aeration — supplying air to diffusers in STP and ETP biological treatment tanks
- Aquaculture — aerating fish ponds and water tanks
- Pneumatic conveying — transporting dry powders, granules, and pellets
- Paper and textile industry — vacuum table holding, yarn texturing
- Chemical and pharmaceutical — inert gas circulation, vacuum drying
Roots Blower vs Centrifugal Blower
| Parameter | Roots Blower | Centrifugal Blower |
|---|---|---|
| Flow type | Positive displacement (constant flow) | Dynamic (flow varies with pressure) |
| Pressure range | Up to 1 kg/cm² | Lower pressure range |
| Efficiency at part load | High | Lower |
| Noise level | Higher (needs acoustic hood) | Lower |
| Best for | High pressure, stable flow | High volume, lower pressure |
Choosing the Right Roots Blower
Key specifications to define before buying:
- Flow rate (m³/hr) — based on your aeration or process demand
- Discharge pressure (kg/cm²) — sum of submergence depth + pipe friction losses
- Motor power (kW) — sized to flow and pressure with a safety margin
- Inlet air temperature — affects volumetric efficiency
- Noise requirements — acoustic enclosures available for sensitive sites
QuaSys Products: Kay Roots Blower
QuaSys Inc. is an authorized dealer for Kay Roots Blowers — twin-lobe positive displacement blowers engineered for reliable performance in wastewater treatment and industrial applications. We also supply Everest and Swam Roots Blowers with flow rates up to 80,000 m³/hr.
To discuss your requirements or request a quotation, contact our team or call +91 11 29531287.
