The difference between the so-called forward centrifuga […]
The difference between the so-called forward centrifugal fan and the backward centrifugal fan is different in the size of the outlet angle of the fan blades. Export angle greater than 90 degrees known as the forward centrifugal fan, less than 90 degrees known as the backward centrifugal fan, equal to 90 degrees called radial centrifugal fan. When the size and speed of the fan are the same, the greater the exit angle, the higher the pressure generated (the specific equation is not listed, can be obtained from the speed triangle). Therefore, the advantages of forward and backward compared to the full pressure head is greater. But the forward tilting maneuvering head accounted for the proportion of the total pressure head is also larger, high air flow rate, the conversion into static pressure when the loss is greater, so the efficiency is not backward to high.
Backward impeller mainly in the pressure of the main, mainly due to the backward than the forward efficiency is widely used. The air volume is small and the wind pressure is small, the noise is relatively small, easy to overload, the price is relatively low; So the general civil construction fan recommended as far as possible the use of backward blade fan. The forward blade fan is used in the industrial building process, or the smoke control system in the civil building (when the backward blade fan can not meet the wind pressure requirements).
When the size, speed and flow rate of the three kinds of leaf impeller are the same, the pressure of the front blade is the largest, the backward blade is the smallest and the radial blade is centered. When the flow rate and rotation speed of the three kinds of leaf impellers are the same, and the full pressure is also the same, the radial dimension of the front blade impeller is the smallest, the size of the backward blade is the largest and the radial blade is centered.
The fan of the front blade is easy to overload, the load is poor, the rear blade impeller fan is not easy to overload, and the radial blade impeller is centered. The noise of the front blade blade impeller fan is low, the noise of the backward blade impeller fan is generally the noise of the radial blade impeller fan. This day, no doubt. Front blade blade impeller fan application range is small, backward blade impeller fan range of applications, radial fan center. The efficiency of the front blade blade impeller is the lowest, and the blade is the highest, and the radial blade is centered.