Manual for the Design of Pipe Systems and Pumps - GEA ...

6.2 Characteristic
curve interpretation
Step 1
Step 2
The flow rate, flow head, the required motor power, the NPSH and efficiency of the pump
are indicated in the pump characteristic.
On the example shown below it is explained how a pump characteristic is to interprete.
Values ascertained so far (from Chapter 6.1):
Flow rate = 24.0 m 3/h
Req. flow head = 33.0 m
NPSH avl = 9.4 m
These are the relevant values for finding out the optimal pump by use of diagrams.
The first diagram to be used is the Q/H Diagram (Fig. 20 - the diagram of a TP 2030). First the
intersection point of the flow rate (24 m 3 /h) with flow head (33 m) should be made out. The
intersection point is located in the area of the impeller of 160 mm in diameter.
The pump efficiency (η) is read in Fig. 20 and amounts to approximately 57 %.
H 0 20 40 60 80 100 120
USGPM
140 160
[ft] [m]
I GPM
0
44
20 40 60 80 100 120
140
140
120
100
40
36
32
Ø160
Ø150
η 0,30 η 0,35
H = 33 m
η 0,40 η 0,45
η 0,50 η 0,55
η 0,60
28 Ø140
80
60
40
20
0
Fig. 20
24
20
16
12
8
4
Ø130
Ø120
Ø110
0
0 5 10 15 20 25
Q = 24 m
30 35
Q
3 /h
26
GEA Tuchenhagen
40