The lift of the fan refers to the phenomenon that when the fan works in an unstable area, the fan volume, pressure, electricity and other fluctuations are large, the noise increases, and the fan and pipeline vibrate violently.

 

 

As long as the operating point does not reach the above unstable areas, fan displacement can be avoided. If the mounting angle of the movable blades of the axial fan changes, the K-point changes accordingly. Attribute montages correspond to, differently. Fan overload alarms are usually designed for large units. The principle is to smoothly connect the peaks of the power curve corresponding to the angle of the moving or stationary shovel to form the overvoltage limit of the fan, and then move the overvoltage line down a certain distance to obtain the E alarm line. In order to ensure the reliable operation of the fan, its operating point must not be located on the lower right side of the voltage limit. Due to changes in the resistance characteristics of the pipe or other reasons, when the operating point moves along an angle on the upper left side of the curve voltage alarm line, an alarm signal is issued to alert the operator to attention and the operating point is returned to the stin position.

 

 

The wind pressure of the parallel fan is equal, so that the rotor blade opening of the low-load fan is small, and the peak (K point) of the power curve is lower than that of another fan, and the lower the load, the lower the K point. The low load point of the fan is easy to fall in the overload zone. Therefore, when adjusting the load of the fan, the load deviation of the two parallel fans should not be too large, so as to avoid the failure of the fan into the unstable overload area E, during operation, if the drainage pipe is not smooth or the inlet pipe is not mixed, the fan will work in the overload area. d Airflow system output error or error, system resistance increases. If the active wing of the parallel wind is not opened according to the instructions or on the spot, the automatic control fails, the characteristics of the fan will change, and the fan will also produce eddy currents. Long-term operation of the fan under low load should be avoided.

 

The so-called wind noise refers to two fans running in parallel. The current (flow) of the fan suddenly increases, and the current (flow) of the fan suddenly decreases. If at this point the valves of the small flow valve and the large flow valve close to the air flow, another small flow valve jumps to the maximum flow rate. When the automatic operation of the regulating valve, the movement and static blade of the fan are frequently opened and closed, resulting in the rise of the thermomotor of the fan, and it will burn out when it is serious.

 

Wind turbulence occurs due to unstable working conditions of parallel fans. The figure above shows the total power curve of two axial fans with the same performance. If there are two fans working in the piping system, point P1 is the system operating point, and each fan is continuously operated to point E1. Wind speed does not occur at this time. If, for any reason, the resistance of the ducting system appears in the fan in the working area of "Let's see the working conditions of point p2". Two fans operate on E2A and E2. The large-flow fan works in the holy stable area, the small-flow fan works in the unstable area, and the imbalance of the two wind turbines is easily destroyed. So there are two fans that bear the phenomenon of wind.