Characteristics of ducted ventilation fans

1. The selection of control parameters for pipeline ventilation fans includes air volume, total pressure, efficiency, noise, motor power, etc.

2. Choose ventilation fans for different purposes based on the physical and chemical properties of the transported gas. If conveying clean air, a general ventilation fan should be selected; When transporting flammable and explosive gases, explosion-proof ventilation fans should be selected; When transporting corrosive gases, corrosion-resistant fans should be selected.

When selecting a ventilation fan, consideration should be given to the air leakage loss and calculation error of the pipeline system, as well as the negative deviation of the actual air volume and air pressure of the ventilation fan. Generally, a safety factor of 1.05-1.1 air volume and 1.10-1.15 air pressure is used. But it should not be too large to prevent the ventilation fan from operating in a low efficiency area for a long time.

4. Pay attention to the matching relationship between the resistance characteristics of the pipeline network and the characteristics of the ventilation fan. To ensure stable operation of the ventilation system, the fan should be operated near its highest efficiency point, with the fan's operating point located on the right side of the peak total pressure point in the performance curve (i.e. the high air volume side, and generally located at 80% of the peak total pressure point).

5. For ventilation systems with noise reduction requirements, it is necessary to first select ventilation fans with high efficiency and low impeller circumferential speed, and make them work near the highest efficiency point. Corresponding noise reduction and vibration reduction measures should also be taken based on the propagation mode of noise and vibration generated by the ventilation system.

6. A ducted ventilation fan is a type of fan that changes the shape of its blades, allowing the airflow to have both axial and centrifugal effects after entering the fan. Therefore, its performance is intermediate between axial and centrifugal fans.

7. The duct ventilation function provides moderate air pressure and moderate air volume, making it suitable for ventilation systems in high-rise civil buildings.