When the pump rotor works at high speed, if its mass is unbalanced, a large centrifugal force will be generated when it rotates, causing vibration or damage to the pump. The balance of the rotor is achieved by the mass balance of each component (including shaft, impeller, shaft sleeve, balance plate, etc.) on the rotor. Therefore, the static balance verification shall be carried out for the newly installed impeller. The specific methods are:

(1) Install the impeller on the dummy shaft and place it on the static balance test bench that has been leveled. There are two tracks on the test bench, on which the dummy shaft can roll freely.

(2) Mark the side where the impeller is biased. If the impeller mass is not balanced, the heavier side will always turn down automatically. Add weight block (stick with surface or use clip to increase or decrease iron sheet) at the symmetrical position of the heavy place (i.e. the lighter side) until the impeller can stop at any position.

(3) Weigh the weight of the weighting block. The weight is not added on the lighter side of the impeller, but is reduced on the heavier side to achieve the balance of the impeller. During weight reduction, the milling machine can be used for milling or the grinding wheel can be used for grinding (when the removal amount is small), but the depth of milling or grinding shall not exceed 1/3 of the thickness of the impeller cover plate. For the impeller after static balance, the allowable deviation value of static balance shall not exceed the product of the impeller outer diameter value and 0.025g/mm. For example, for an impeller with a diameter of 200mm, the allowable deviation is 5g.