What is the difference between a forward inclined centrifugal fan and a backward inclined centrifugal fan

The fan air volume and pressure of the forward inclined impeller can not be too large. The principle is to rely on the blade to press the air. The power curve is overload and radial. Therefore, when the parameters reach a certain limit, the impeller is easy to deform, which is used more in the HVAC industry. The backward inclined impeller avoids the disadvantages of the forward inclined impeller. It uses the impeller to cut the wind, and the power curve is parabola. It is non overload design, and the parameters can be large, which is applicable to many industries.