This force, resulting from unbalanced compressive forces, acts in axial direction on the shafts of pumps, mixers, agitators etc., and can change magnitude and direction during operation and when the machine has stopped. Magnitude and direction of the axial thrust must be taken into consideration in the selection of components which transfer the axial thrust and in the shaft bearing. Agitator mechanical seals with built-in (floating) bearing must not take up any axial thrust. (DIN28138, T1, T2; each 2.4). Shaft displacements may arise due to the axial thrust and the end float, and have to be compensated by the mechanical seal.