If the total pressure selected for the fan is too high, will both the negative pressure in front of the fan and the pressure behind it increase?
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If the total pressure selected for the fan is too high, will both the negative pressure in front of the fan and the pressure behind it increase?
If the total pressure of the fan is chosen to be higher than what is actually required, then both the negative pressure in front of the fan and the positive pressure behind it will indeed increase. This is because the fan needs to generate sufficient airflow to overcome the resistance in the system; as the total pressure increases, the fan requires more energy to achieve this, which results in an increase in both the negative pressure ahead and the positive pressure behind it. However, if the total pressure is too high, it may cause unstable operation of the fan or increased noise; therefore, it is necessary to select an appropriate total pressure value based on the actual conditions. .
When the drive motor of a centrifugal fan is a non-frequency-variable motor, it is usually necessary to install a return pipeline and a return control valve from the fan’s outlet to its inlet, in order to maintain stable pressure at the fan’s inlet by adjusting the return flow rate. The level of pressure at the fan outlet depends primarily on the pressure drop in the system downstream of the outlet. If the total pressure developed by the fan at its rated flow rate is significantly higher than the corresponding pressure drop in the system downstream, then valves capable of regulating flow should be installed in the pipelines downstream of the outlet to prevent the fan from being overloaded.