Civil Engineering Reference
In-Depth Information
Fig. 26-28.
Loss coefficients for butterfly valves (
Source:
Reference 7; courtesy of the BHR
Group Limited)
Heads much lower than head at peak efficiency of pump
•
Capacity much higher than capacity at peak efficiency of pump
•
Suction lift higher or positive head lower than that recommended by manufacturer
•
Liquid temperatures higher than that used to design the system
•
Speeds higher than manufacturer's recommendations
•
The simplest method of avoiding cavitation in pumps is to make sure that the NPSHA
is at least 2 to 5 feet larger than the NPSHR.
Open Channels
Open channel flow is used to convey water through many of the water plant processes.
Open channel flow occurs in basins, conveyance channels, split boxes, flumes, launders
or troughs, and over weirs. Under most circumstances, the flow can be assumed to
