In centrifugal pumps the energy is transferred hydrodynamically.In the hydrodynamic transfer of energy the fluid is accelerated by the impeller of the centrifugal pump. Therefore, the impeller of the centrifugal pump has to move with high velocity and thus a high rotational speed.

During the suction phase the side channel pump operates according to the positive displacement principle. As soon as the suction process is over, the side channel pump starts working like a centrifugal pump. The centrifugal force of the rotating impeller separates the fluid and gas. Side channel pumps are therefore self-priming pumps.

Axial-flow pumps are also known as propeller pumps. Axial-flow pumps come with fixed blades and with variable blades. The flow passes through the impeller in axial direction. In axial-flow pumps, the pressure is not built up by the effect of centrifugal force but, like the aerodynamic principle, by the propeller blade.

In positive displacement pumps the energy is transferred to the fluid hydrostatically. In the hydrostatic transfer of energy a displacement body reduces a working chamber filled with fluid and pumps the fluid into the pipe.

A characteristic of fans is the pressure ratio, which indicates the ratio of the absolute final pressure to the absolute intake pressure. Fans are different from compressors because of their low pressure ratio of max. 2,5.

Engineering animations such as cutaway models are ideally suited to representing processes and functions. GUNT uses up-to-date original parts for its cutaway models. Movement and switching functions are maintained.