How to choose a blower？
- Centrifugal Blowers
- Rotary Lobe Blowers
- Helical Screw Blowers
How to choose a blower？
What is a Blower?
Simply put, a blower is a device designed to increase the flow rate of air. In technical terms, its purpose is to convey air and gases from low pressure to high pressure to fulfill specific tasks. Blowers are widely used across various industries for applications such as cooling, conveying, ventilation, and exhaust. Whenever the pressure requirement falls between that of a fan and a compressor, a blower is generally used.
Common Types of Blowers:
Positive Displacement Blowers
Positive displacement blowers can be further divided into Rotary Lobe Blowers and Helical Screw Blowers.
Centrifugal Blowers
High-Speed Blowers
Regenerative Blowers
How Do Blowers Work?
Blowers operate by utilizing the centrifugal motion of rotors to increase the pressure of air or gas. They draw air/gas through an intake valve and then rotate the impeller (or rotor) to generate centrifugal force to move the air or gas. During this process, the air or gas gets compressed, resulting in a linear increase in pressure.
Types of Blowers
Blowers can be categorized into four main types, each with its unique advantages and applications:
1. Positive Displacement Blowers
Positive displacement blowers are ideal for applications involving air or neutral gases. They work in a relatively simple manner: air or gas enters a portion where the volume increases and exits from a portion where the volume decreases. As the ratio between the inlet and outlet points changes, the release of air/gas from the smaller side creates positive displacement, which increases the pressure. A key feature of these blowers is that the airflow remains constant, regardless of pressure fluctuations.
Rotary Lobe Blowers
Rotary lobe blowers are a specific type of positive displacement blower that operates using two counter-rotating rotors. The air is drawn into the blower, where the blades rotate it and push it outward.
These blowers are capable of handling large volumes of air, making them suitable for larger vacuum systems. They are commonly used in applications like aeration tanks for oxygenation, where moderate pressure (around 15 psi) is sufficient.
Helical Screw Blowers
Helical screw blowers are capable of producing higher pressures than rotary lobe blowers. Equipped with two rotors, each with blades (usually two or three), a helical screw blower achieves compression by meshing the blades of the primary rotor with the secondary rotor.
Thanks to the unique screw shape of the blades, helical screw blowers deliver higher and more precise pressures. The screw geometry works by compressing the air between the rotors. These rotors are precisely calibrated to avoid any contact between them.
2. Centrifugal Blowers
Centrifugal blowers are typically used in applications requiring high pressure and variable flow. These blowers feature rotating impellers that increase the velocity of air (or gas) as it passes through. Additionally, as the air enters the fan wheel, it turns 90 degrees and exits the blower at a much faster speed. This type of blower is ideal for the continuous delivery of gases. When the gas passes through, its kinetic energy increases, generating sufficient pressure upon release.
A commonly used centrifugal blower is the multistage centrifugal blower. This rotary machine increases the pressure of air or gas using centrifugal force generated by an electric motor. The high-pressure resistance and flow capacity make it excellent for applications requiring the generation of high pressure with small airflow, such as aeration in wastewater treatment, landfill gas boosting, or powering artificial lungs in the medical industry.
3. High-Speed Blowers
High-speed blowers are designed to meet high-pressure demand (up to 25 psi) and high flow rate requirements (up to 15,000 cubic meters per hour). Powered by electric motors, high-speed blowers feature impellers with dual suction points for increased efficiency. These impellers are directly coupled with permanent magnet synchronous motors (PMSMs) driven by variable frequency drives (VFDs), allowing for speed control while maintaining reliable operation.
4. Regenerative Blowers
Regenerative blowers are specifically designed for applications that require moving large volumes of air at relatively low pressure. These blowers often operate without oil components, making them both easy to maintain and very safe for use in industries like food and beverage or healthcare.
Regenerative blowers create pressure through the displacement of air molecules. As the impeller rotates, it pulls air into the blades and recirculates the air from the bottom back to the impeller. This non-positive displacement blower forces airflow while continuously capturing air and pushing it forward.
Conclusion:
The type of blower you select depends on your specific application and business needs. For high-pressure requirements, high-speed turbo blowers are an ideal choice, while for low-pressure applications, regenerative blowers may be more suitable.
For detailed product selection advice, please consult with the Eethink pre-sales engineers!