In the balance process of centrifugal fan, the measured unbalance is mainly eliminated by checking operation after measurement. The balancing weight is generally added to the lighter part of the rotor or the heavier part is removed during correction. In addition, very few rotors, such as fan blades, can be balanced by bending the blades, that is, changing the shape of the rotor. As an unbalance check method of centrifugal fan, some machining methods can be used.
In order to balance the centrifugal fan, the correction weight block can be arranged in the opposite direction of its unbalance, but it is required that the correction weight block is suitable for the shape and structure of the rotor, and several kinds of balance weight blocks are prepared according to the size of the unbalance amount. In order to make the operation convenient.
Sometimes the balance can be achieved by welding method, which is usually used by convex welding. The strip used has a certain width and thickness, and the length depends on the unbalance. The general centrifugal fan impeller also adopts the electric welding method to carry on the counterweight balance. However, if the rotor of the small motor is balanced, sometimes the soldering method is used, and the weight of the welding is selected according to the magnitude of the unbalance during the check.
When the centrifugal fan is balanced, the rivet can also be used as a balance block. Compared with other methods such as tin welding, this method can generally be corrected accurately, so this method can be used in the blades of the centrifugal fan, the turbine and the friction plate of the clutch.
Removing weight in the unbalanced direction of the centrifugal fan is also a common way to correct it, not only by drilling the bit into the rotor to eliminate the imbalance, but also by boring and grinding. Chisel and milling to correct the balance of centrifugal fans.
Boring is used in the coarse balance of large decelerating gears with large unbalance, which is hardly used in precision balance, while grinding is suitable for smooth rotor, such as blade, impeller of pump, rotor of centrifugal separator and magnetic drum. Chisels are used for turbines and large gears; milling is used for rotors with uniform thickness in balance or stiffeners.http://www.jnblower.com/