Environmental Engineering Reference
In-Depth Information
Solution:
NPSHA = 34 ft + 15 ft - 0.6 ft - 0.4 ft - 2 ft = 46 ft
3.2.11.1.2 nPSha: Suction lift from open reservoir
Example 3.11
Problem:
Find the NPSHA in Figure 3.6, where:
Liquid = water
Temperature (
t
) = 60°F
Specific gravity = 1.0
P
a
= 14.7 psia (34 ft)
h
= -20 ft
P
v
= 0.256 psia (0.6 ft)
h
e
= 0.4 ft
h
f
= 2 ft
q
= 120 gpm
Solution:
NPSHA = 34 ft + (-20 ft) - 0.6 ft - 0.4 ft - 2 ft = 11 ft
3.2.12 Pumps in series and Parallel
Parallel
operation occurs when two pumps discharge into a com-
mon header. This type of connection is advantageous when the system
demand varies greatly. An advantage of operating pumps in parallel
4 ft
20 ft
figure 3.6 Suction lift from open reservoir.
