Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

Volute Design 59
Figure 5-5. Typical single-volute layout.
The universal volute sections for such a design are shown in Figure 5-8.
A rectangular volute casing requires the same throat area as a standard
volute casing and should be laid out according to the principle of constant
velocity.
Rectangular volutes are widely used in small single-stage and multistage
pumps. The benefits of the rectangular volute are strictly economical.
The simple volute section yields a considerable cost savings due to
reduced pattern costs and production time. Over the range of specific
speeds where it is used the hydraulic losses are negligible.
The Design of Circular Volutes
The details of a typical circular volute casing design are shown in Figure
5-9, The ratio between the impeller diameter, D 2 , and the volute di-