Volume 8 – Mechanical and Electrical Services - Malaysia Geoportal

Chapter 1 PUMPING INSTALLATION
Some simple guidelines for sump design are as follows:
- Design the sump for a flow velocity in the sump channels of about 0.3 m/sec at the lowest
sump water level.
- Avoid sudden changes in the direction of flow.
- Abrupt changes in sump floor elevations should not be permitted within about five bell
mouth diameters from the side of the pump.
- The flow should be parallel to the sump walls.
The design of the pump sump is important particularly for large axial-flow and mixed-flow pumps.
The suction side of the pump affects pump performance adversely, poor flow condition in the suction
well or poor entrance conditions about the pump-suction well will cause poor performance and
vibration, vortex formations, overloading of the driver etc. Generally the flow of water into any pump
should be uniform, steady, without swirl and without entrained air. Typical examples of undesirable
suction sump configuration and their improvements are as shown in Fig. 1.8 (a) & (b). Any deviation
from the basic design rules requires that sump model tests be performed. Whenever new design
departs significantly from established configurations, model tests of the pump sump and its
approaches should be conducted.
1-14 March 2009