Introduction
Roots blowers, also known as lobe blowers, are mainly used in applications that require a large amount of low - pressure air/gas. They can generate a constant air flow regardless of the exhaust pressure conditions, providing air flow rates from small to large. Therefore, we use this type of blower in many industries, such as the aeration tanks of sewage treatment plants, the pneumatic conveying lines of grain processing plants, and drag races.
However, Roots blowers come in various types, each suitable for different application systems. In this article, we will discuss the specific working principles of Roots blowers and the characteristics of different types, so that you can easily choose the right one.
What is a Roots Blower?
The Roots blower was invented by the Roots brothers in the United States in 1854 and got its name from them. This blower uses two involute - shaped impellers (two - lobe or three - lobe structure) that rotate in reverse synchronously in the casing. That is, it is a low - pressure blower that uses constant - volume compression.
This working method means that during operation, the volume of air in the compression chamber remains constant. However, the impeller rotors in the chamber keep rotating, reducing the volume of the compression chamber and causing compression. It is characterized by its forced - air - supply ability, maintaining a constant flow even when the pressure fluctuates.
Its Main Working Process
(1) Suction stage: The Roots blower has two impellers. Driven by the motor, the two impellers rotate in opposite directions. When the impellers disengage, a negative - pressure area is formed to suck in gas.
(2) Conveying stage: The impellers continue to rotate, and the inhaled gas is trapped in the enclosed space formed by the impellers and the casing. It does not mix with other gases and does not leak, but is smoothly conveyed from the air inlet to the air outlet as the impellers rotate.
(3) Exhaust stage: At this time, the impellers engage again to squeeze the gas to the air outlet. The gas will be discharged into the pipeline or equipment outside the blower.
What Types are Roots Blowers Divided Into?
Roots blowers come in a variety of types, mainly divided into two - lobe, three - lobe, high - speed turbo, and industrial types. The following is a comparison of some of their parameters, as well as a detailed introduction:
|
Type |
Two-Leaf Roots Blower |
Three-Leaf Roots Blower |
High-Speed Turbo Blower |
Industrial Blower |
|
Pulsation amplitude |
Larger (±25%) |
Smaller (±15%) |
Generally smaller (±10% - ±20%) |
Relatively large (±20% - ±30%) |
|
Noise level |
75 - 85dB(A) |
70 - 80dB(A) |
60 - 70dB (A) |
70 - 90dB (A) |
|
Applicable pressure |
≤49kPa |
≤98kPa |
≥300kPa and above |
10kPa - 500kPa or wider |
Two - lobe Roots Blower
The two - lobe Roots blower uses two interlocking blades to move air or gas. Its pumping capacity is determined by the size, operating speed, and pressure conditions.
This blower is compatible with a wide range of pressures, but compared with other types of Roots blowers, its efficiency is relatively low. It is often used for the following purposes:
• Aeration tanks in sewage treatment
• Fish ponds in aquaculture
• Conveying systems in pharmaceutical factories
Three - lobe Roots Blower
It is a pump that uses three blades/rotors to convey air or gas. Compared with the two - lobe Roots blower, the number of impellers has increased. This gives it better pulsation performance and lower operating noise. Its applications include:
• Vacuum packaging of food
• Drying and sterilization of pharmaceuticals
• Vacuum packaging of electronic components and precision instruments
High - speed Turbo Blower
This blower often combines a single - stage centrifugal blower with an energy management system. It uses turbocharging technology and can compress air at high speed. With a rotational speed of up to 10,000 revolutions per minute, it can provide a huge air volume for your application. However, it produces relatively high noise, and you need to take some noise - reduction measures during operation, such as installing a muffler. High - speed turbo blowers are mainly used in industrial applications and wastewater treatment, such as:
• Aeration in large - scale sewage treatment plants
• Flue gas desulfurization in thermal power plants
• Blowing in blast furnaces
Industrial Blower
The industrial blower is mainly composed of an impeller, a casing, an air - inlet collector, a deflector, a motor, etc. It is further divided into centrifugal, axial - flow, mixed - flow, etc. types. It supports a wide range of air volume and pressure adjustments and can quickly enhance air circulation in large - area spaces, including:
• Ventilation in factories, workshops, and warehouses
• Industrial dust - removal equipment
• Drying of large - sized wood
Conclusion
Through detailed understanding, we already know what a Roots blower is and how it operates. We also know that it is mainly divided into four types: two - lobe Roots blower, three - lobe Roots blower, high - speed turbo blower, and industrial blower, as well as their characteristics.
If you are interested in them but don't know how to choose the right one for your application, please feel free to contact us. The professional engineering team of AquaSust is very happy to provide you with professional selection advice.