What is the difference between centrifugal fan and Roots blower
Centrifugal fans and Roots fans are two different types of fans, and they have significant differences in multiple aspects. The following is a detailed comparison of these two types of fans:
1、 Working principle
1. Centrifugal fan: A centrifugal fan is a mechanical device that relies on input mechanical energy to increase gas pressure and discharge gas. It uses the centrifugal force of the rotor to accelerate and compress the gas, thereby transporting it from the low-pressure area to the high-pressure area. Centrifugal fans usually use curved blades, and gas is thrown to the casing under the action of the blades, forming high-pressure gas.
2. Roots blower: Roots blower is a positive displacement fan that compresses gas through a small gap between two 8-shaped blades (or three bladed rotors). When the rotor rotates, the gas between the two blades is constantly squeezed, thereby transporting the gas from the suction side to the discharge side. The air volume conveyed by the Roots blower is proportional to the rotational speed, so the air volume can be adjusted by adjusting the rotational speed.
2、 Performance characteristics
1. Pressure and air volume:
Centrifugal fan: usually used in situations that require high air volume but low pressure requirements. The pressure change of a centrifugal fan has a significant impact on the air volume. When the pressure increases, the air volume will decrease accordingly.
Roots blower: It is suitable for situations where the air volume requirement is not high but the pressure requirement is high. The pressure change of Roots blower has little effect on the air volume, and the air volume is mainly proportional to the speed.
2. Noise and vibration:
Centrifugal fan: Due to its complex structure and high operating speed, it produces relatively high noise and vibration.
Roots blower: The three bladed rotor structure results in low vibration, low noise, and smoother operation.
3. Efficiency and energy consumption:
Centrifugal fan: Under the same conveying gas pressure, centrifugal fans of the same specifications may have lower efficiency than Roots fans.
Roots blower: has high efficiency and relatively low energy consumption. The special curve design and reasonable meshing method reduce leakage and improve volumetric efficiency.
3、 Application scope
1. Centrifugal fan: widely used for ventilation, dust removal, and cooling in factories, mines, tunnels, cooling towers, vehicles, ships, and buildings; Ventilation and induced draft of boilers and industrial furnaces. Centrifugal fans are suitable for large-scale ventilation, exhaust, and supply systems, such as buildings, factories, underground garages, and other fields for ventilation and air exchange.
2. Roots blower: suitable for low-pressure, high flow gas compression fields, such as sewage treatment, food processing, aquaculture and other industries. Roots blowers are also commonly used in applications that require constant flow efficiency, such as aeration systems in wastewater treatment.
4、 Maintenance cost
1. Centrifugal fan: Maintenance is relatively simple, just regularly check the service life of components such as oil and belts, and perform maintenance.
2. Roots blower: easy to clean and maintain. But it is necessary to pay attention to regularly replacing lubricating oil and checking the wear of components such as bearings.
In summary, there are significant differences between centrifugal fans and Roots fans in terms of working principles, performance characteristics, application scope, and maintenance costs. The choice of fan depends on specific application requirements and working environment.
