The lateral hydraulic loads on the impeller can be estimated with the following formula:

Lh = 19,000 Hp*i / ( N D )

Where Hp*i is the fraction of the motor horsepower delivered to the impeller. The value is the motor horsepower in horsepower if only one impeller is present. The value of N is rotational speed in rpm and the value of D is the impeller diameter in inches. The result is the lateral hydraulic load in pounds force.

If the impeller operates at the liquid level or in gas dispersion a multiplier of about 3.0 should be applied to the result. With the load a simply supported beam formula can be used to estimate the lateral bearing loads and the bending moment on the shaft.

For further information, consult a mechanical or mixer design reference.