8. Pumps

The fundamentals of pump operation have been fully treated in the foregoing chapters. Three particular aspects are discussed in the present chapter. The first is evaporation of the fluid in liquid state when the pressure inside the pump becomes lower than the vapour pressure. Cavities with vapour then emerge and the phenomenon is generally described as cavitation. The second concerns starting up. Priming is necessary. This is filling the pump and the suction pipe with the liquid to be pumped. The third topic is the intersection of the pump characteristic with the load characteristic, which mostly has a large static part. The intersection does not necessarily result in a stable operating point. Cavitation, priming and stability are discussed in the present chapter. Further topics are some aspects concerning shaping of the components, construction and special applications.