The working principle of the Roots blower

The Roots blower is a volumetric rotary high-pressure blower named after its inventors, the American Roots brothers. The Roots blower has two rotors that rotate in opposite directions driven by a motor. When the rotors pass the intake port, a sealed chamber is formed between the two rotors and the wall and casing. As the rotors continue to rotate, the air inside the sealed chamber is compressed and expelled through the exhaust port. This process continuously draws in and expels outside air. The two rotors must not collide with each other or with the casing and side covers, while also ensuring that gaps are not too large to affect efficiency. A small gap is always maintained between the two rotors during operation to prevent the expelled gas from returning to the intake chamber.

Its characteristic is that the output air volume is proportional to the rotational speed. When the outlet pressure of the blower changes, the output air volume does not significantly vary. The Roots blower has a high pressure, and its efficiency far exceeds that of air compressors when the pressure is below one hundred kilopascals. It is widely used as an essential source of gas in sewage treatment, pneumatic conveying, and aeration.