Page 276 - Centrifugal Pumps Design and Application

Slurry Pumps 245

Where there exists a density difference between the conveying liquid
and the solid particles, the particles will tend to settle. Usually slurries
with a distribution of larger particles will be "settling," and the particles
and the liquid will exhibit their own characteristics. As the liquid passes
over the particles, energy is dissipated due to the liquid "drag" that re-
duces pump head and efficiency.
Actual tests indicate that for practical purposes, the amount of head
derate will be the same as the efficiency derate. A typical pump perfor-
mance characteristic for slurry mixture with coarse particles is shown in
Figure 13-lib.
Performance correction factors for slurries are usually based on pre-
vious test data. In the absence of such data, reference should be made to
the pump manufacturer.