Coupling alignment
Coupling alignment is essential to ensure the trouble-free mechanical operation of a
pump set
and to avoid damage to the transmission elements. It involves maintaining the prescribed distance (a) between the coupling halves (see Shaft coupling
). See Fig. 1 Coupling alignment
Fig. 1 Coupling alignment: Flexible coupling alignment using straight-edge and feeler gauge
Furthermore, the shaft centrelines must be precisely aligned with one another at the coupling, and any lateral, height or angular misalignment must be compensated. See Figs. 3, 4 Coupling alignment
Fig. 3 Coupling alignment: Lateral or height misalignment
Fig. 4 Coupling alignment: Angular misalignment
The alignment should be checked, preferably by means of a straight-edge and feeler gauge. See Fig. 1 Coupling alignment
A coupling is correctly aligned if a straight-edge laid across both coupling halves parallel to the shaft maintains the same distance from the shaft at all points around its circumference. In addition, the
axial
distance between the coupling halves should remain the same at all points around the circumference.Accurate alignment can be achieved quickly using an alignment jig. See Fig. 2 Coupling alignment
Fig. 2 Coupling alignment: Flexible coupling alignment using an alignment jig
The required degree of coupling alignment accuracy depends mainly on the coupling type and the
rotational speed
In the case of hot water pump
coupling alignment, it is important to observe the pump manufacturer's special instructions relating to thermal deformations associated with hot water pumps. After completing coupling alignment, it is advisable to pin the pump incl. drive to the baseplate or pump foundation
, to prevent shifting of the pump set during operation.