Do You Know How To Align The Coupling Of Centrifugal Pump?

Alignment of coupling is also called alignment. After the centrifugal pump and motor are installed, the last work is to find the concentricity between the centrifugal pump and the motor, that is to make the axis of the centrifugal pump and the prime mover in the same straight line, so that it does not cause vibration in operation. When the newly installed centrifugal pump is aligned, the radial and axial errors of the coupling may occur in the following four situations:

Alignment of coupling is also called alignment. After the centrifugal pump and motor are installed, the last work is to find the concentricity between the pump and the motor, that is to make the axis of the pump and the prime mover in the same straight line, so that it does not cause vibration in operation. When the newly installed centrifugal pump is aligned, the radial and axial errors of the coupling may occur in the following four situations:

centrifugal pump


The general centrifugal pump (water pump, small oil pump) can be roughly measured with a flat ruler or feeler gauge, but most of the equipment needs to be precisely measured with a dial indicator. Generally, the levelness of the pump has been found. Based on the wheel alignment of the pump, measure and adjust the wheel alignment of the motor to ensure the alignment of the two shafts of the motor and the centrifugal pump.



Note: A1, A2, A3, A4 represent radial clearance, S1, S2, S3, S4 represent radial clearance A1 and axial clearance S1 when the dial indicator is at 0 °, and then measure the radial and axial clearance of 90 °, 180 °, 270 °, respectively, and record them inside and outside the circle as shown in the figure above. When the measurement returns to 0 °, it must be consistent with the original reading. Otherwise, it is necessary to find out the cause, which is generally caused by shaft movement or foundation bolt loosening. Finally, the measurement data must meet the following conditions to indicate that the calculation is correct.


Method 2:

Put the dial indicator on the centrifugal pump end, set the dial indicator to zero, rotate the counter wheel once, and get a value every 90 degrees. At last, when the dial indicator turns back to its starting position, it must return to zero. The sum of left and right readings should be equal to the sum of the upper and lower values. Then, the relative spatial position of the two axes is analyzed according to the readings, and the appropriate adjustment is made according to the deviation value. First adjust the left and right deviation of the coupling to the allowable value, then adjust the height to the standard.

Alignment formula:


S1 = ± (difference in opposite direction of axle (absolute value of opening) × distance from foot 1 to measuring point) ÷ diameter of measuring point ± circumferential radial insertion (difference) / 2;


S2 = ± (difference in axle direction × distance from foot 2 to measuring point) ÷ diameter of measuring point ± circumferential radial insertion (difference) / 2.


The first ±: if the opposite wheel is the upper opening, take the "+" sign; if it is the lower opening, take the "-" sign, which can be understood as from the top to the bottom;


The second ±: take "+" when the motor is low; take "-" when the motor is high, it can be understood that the table from top to bottom is positive write or negative write.


If S1 is positive (upper opening and lower motor), it indicates that gasket should be padded, and S1 number is the thickness of gasket to be padded.


Another: the diameter of the measuring point is the rotating diameter of the measuring point, not the diameter of the coupling of the centrifugal pump . Adjust left and right to be similar.

centrifugal pump2


Method 3 calculation method of adding and subtracting cushions



Among them:

A is the axial meter reading

D is the diameter of coupling

L1 refers to the front foot distance of backrest to motor

L2 is the distance from the front foot to the rear foot of the motor

S is the reading of radial meter


After learning the skills,hope you could do a good job on the alignment and make sure the centrifugal pump a durable life!