CR, CRI, CRN, CRE, CRIE, CRNE
21
Selection and sizing
Selection of pumps
Selection of pumps should be based on
• The duty point of the pump (see section 1)
• Sizing data such as pressure loss as a result of
height differences, friction loss in the pipework,
pump efficiency etc. (see section 2)
• Pump materials (see section 3)
• Pump connections (see section 4)
• Shaft seal (see section 5).
1. Duty point of the pump
From a duty point it is possible to select a pump on the
basis of the curve charts in the section Performance
curves/Technical data starting on page 26.
Fig. 17 Example of a curve chart
2. Sizing data
When sizing a pump the following must be taken into
account.
• Required flow and pressure at the point of use.
• Pressure loss as a result of height differences
(H
geo
).
• Friction loss in the pipework (H
f
).
It may be necessary to account for pressure loss in
connection with long pipes, bends or valves, etc.
• Best efficiency at the estimated duty point.
• NPSH value.
For calculation of the NPSH value, see Minimum
inlet pressure - NPSHA on page 24.
Fig. 18 Sizing data
Efficiency
Before determining the point of best efficiency the
operation pattern of the pump needs to be identified. Is
the pump expected to operate at the same duty point,
then select a CR pump which is operating at a duty
point corresponding with the best efficiency of the
pump.
Fig. 19 Example of a CR pump’s duty point
As the pump is sized on the basis of the highest
possible flow, it is important to always have the duty
point to the right of the optimum efficiency point (see
fig. 20, range with check mark). This must be
considered in order to keep efficiency high when the
flow drops.
Fig. 20 Best efficiency
T
M
02
00
39
13
03
0
20
40
60
80
100
120
140
160
180
200
Q [US GPM]
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
[ft]
H
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
[ft]
H
0
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
[m]
H
0
5
10
15
20
25
30
35
40
45
Q [m3/h ]
CR(E) 32
2-pole, 60 Hz
CRN(E) 32
-11-2
-10
-1
-1-1
-10-2
-2
-2-1
-2-2
-3
-3-2
-4
-4-2
-5
-5-2
-6
-6-2
-7
-7-2
-8
-8-2
-9
-9-2
0
20
40
60
80
100
120
140
160
180
200
Q [US GPM]
0
1
2
3
4
P2
[hp]
0
20
40
60
80
[%]
Eff
0
1
2
P2
[kW ]
P2 1/1
P2 2/3
Eff
0
20
40
60
80
100
120
140
160
180
200
Q [US GPM]
0
10
20
30
NPSH
[ft]
0
10
20
30
[ft]
H
0
4
8
[m]
H
NPSHR
TM
02 671
1
14
03
TM
02 003
9 130
3
TM
02
85
79
05
04
H
f
NPSHR
H
geo
Required flow,
required pressure
Required flow,
required pressure
0
20
40
60
80
100
120
140
160
180
200
Q [US GPM]
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
[ft]
H
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
850
900
950
1000
[ft]
H
0
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
[m]
H
0
5
10
15
20
25
30
35
40
45
Q [m3/h ]
CR(E) 32
2-pole, 60 Hz
CRN(E) 32
-11-2
-10
-1
-1-1
-10-2
-2
-2-1
-2-2
-3
-3-2
-4
-4-2
-5
-5-2
-6
-6-2
-7
-7-2
-8
-8-2
-9
-9-2
0
20
40
60
80
100
120
140
160
180
200
Q [US GPM]
0
1
2
3
4
P2
[hp]
0
20
40
60
80
[%]
Eff
0
1
2
P2
[kW ]
P2 1/1
P2 2/3
Eff
0
10
20
30
NPSH
[ft]
0
10
20
30
[ft]
H
0
4
8
[m]
H
NPSHR
Duty
point
Best
efficiency
eff
US GPM
Optimum point
