The Design of Large Pumping Installations for Low and Medium Heads

This paper is concerned with the factors involved in the selection of the most suitable designs of pumping installations, particularly of the larger sizes, and, in the first place, discusses the effects of the different types of pump on the construction of the pumping station. It goes on to demonstrate the relative advantages of different designs over the wide range of specific speeds available.

Methods of determining the most suitable hydraulic characteristics in three typical cases are examined and the effects of these factors on the first cost and running and maintenance costs are considered. As most selections are usually a compromise between the ideal hydraulic characteristics and those available from the pump and prime mover, the relative merits of constant-speed, variable-speed, and variable-pitch impellers are discussed. Certain aspects of the methods in use for priming pumps are considered and the chief causes of pressure surges in pipe-lines are briefly outlined.

The paper concludes with a discussion of the various factors which may decide whether it is desirable that the plant shall be automatically operated, centrally controlled, or individually controlled.