There are significant differences between Roots blower and axial flow blower in multiple aspects. The following is a detailed comparison of these two types of fans:
1、 Working principle
1. Roots blower:
Through gear transmission on the master and slave shafts, two "8" - shaped involute impellers rotate in opposite directions at a constant speed to complete the suction, compression, and exhaust processes.
Gas is drawn in from the inlet side, and as the volume of the working chamber formed during rotation decreases, the gas is compressed and discharged from the outlet side.
The drum blades of a Roots blower can rotate, but their volume size does not change with rotation, making it a pulsating, continuous, and uniform air supply fan.
2. Axial flow fan:
Axial flow fan is a ventilation fan that uses the thrust of blades to force gas to flow along the axial direction.
When the prime mover drives the impeller to rotate inside the casing, the installation angle between the shaft and the propeller shaped blades exerts a thrust on the gas, pushing it to flow continuously in the direction of the shaft, causing the gas to be continuously sucked in and discharged.
The airflow direction is in the same direction as the axis of the fan blades. When the impeller rotates, gas enters the impeller from the inlet axis, and then rises due to the pushing of the blades on the impeller, and then flows into the guide vanes.
2、 Structural characteristics
1. Roots blower:
The structure is relatively complex, consisting of a rotor, stator, air inlet, air outlet, transmission, etc.
The gears of the rotor and stator cooperate to form several compression chambers, gradually increasing the gas pressure and discharging it at the outlet.
There is no contact between the rotor and stator, so it will not cause gas pollution.
2. Axial flow fan:
The structure is relatively simple, usually consisting of a casing, impeller, motor, etc.
The impeller is fan-shaped with many blades, and there is a gap between the impeller and the casing.
Guide vanes are used to change the direction of airflow and increase the pressure of the airflow.
3、 Performance characteristics
1. Roots blower:
Forced gas delivery has little effect on the air volume when the outlet resistance varies within a certain range.
The gas is pure, dry, and does not require lubrication.
High efficiency, but the maintenance process is relatively complex, and high precision is required for the machining of rotating parts and the inner wall of the casing.
The noise is loud, but it can be reduced by devices such as mufflers.
2. Axial flow fan:
High flow rate and low wind pressure.
Small size, light weight, easy to install and maintain.
The noise is relatively low, but slightly higher than that of the Roots fan.
Suitable for situations with high air volume and low air pressure.
4、 Application scenarios
1. Roots blower:
Mainly used in fields such as chemical engineering, electricity, and mining.
Suitable for processes that require gas transportation to distant locations.
It can meet the demand for conveying gases with high pressure and flow rate.
2. Axial flow fan:
Mainly used in large-scale ventilation engineering, air conditioning systems, tunnel ventilation and other places.
Suitable for situations with high flow requirements and low pressure requirements.
Commonly used in fields such as ventilation, cooling, and air exchange.
In summary, there are significant differences between Roots blowers and axial flow blowers in terms of working principles, structural characteristics, performance characteristics, and application scenarios. Users should weigh and choose based on their specific needs when making choices.
