Civil Engineering Reference
In-Depth Information
120
Percent Efficiency
50
60
65 70
75
80
100
82
84
80
82
80
60
75
70
40
14-in. Impeller
Diameter
20
12-in. Impeller
Diameter
10-in. Impeller
Diameter
0
500
600
700
800
900
1,000 1,100
0
100
200
300
400
Flow, gpm
Fig. 29-7.
Centrifugal pump curves for various impeller diameters
where:
Q
1
,
Q
2
capacity at condition 1 and condition 2
H
1
,
H
2
head at condition 1 and condition 2
D
1
,
D
2
impeller diameter at condition 1 and condition 2
N
1
,
N
2
impeller rpm at condition 1 and condition 2
E
1
,
E
2
pump efficiency at condition 1 and condition 2
BHP
1
, BHP
2
power (''brake horsepower'' in U.S. customary terms) at condition 1
and condition 2
120
Percent Efficiency
50
60
65 70
75
80
100
N
1
=
1,750 rpm
82
84
80
82
80
75
70
60
40
20
N
2
=
1,150 rpm
0
500
600
700
800
900
1,000 1,100
0
100
200
300
400
Flow, gpm
Fig. 29-8.
Centrifugal pump curves for various impeller speeds
