MTR(E), MTC, MTA - Grundfos

MTR(E), MTC, MTA 1
MTR(E) selection and sizing
Selection of pumps
Selection of pumps should be based on
• the duty point of the pump
• sizing data such as pressure loss as a result of
height differences, friction loss in the pipework,
pump efficiency etc.
• minimum inlet pressure - NPSHR.
1. Duty point of the pump
From a duty point it is possible to select a pump on the
basis of the curve charts shown in the chapter of
"Performance curves/Technical data starting on page
page 26.
p
[kPa]
2000
1600
1200
800
400
0
H
[m]
240
220
200
180
160
140
120
100
80
60
40
20
0
P2
[kW]
2.4
1.6
0.8
0.0
NPSH
[m]
8
6
4
2
0
-8
-7
-6
-5
-4
-3
-2
-1
-2-1
-1-1
0 100 200 300 400 500 600 700 800 Q [l/min]
0 10 20 30 40 Q [m³/h]
Fig. 21 Example of a curve chart
MTRE 32
MTR,
Hz 60
ISO 9906 Annex A
1/1 P2
Eta
0 100 200 300 400 500 600 700 800 Q [l/min]
2. Sizing data
When sizing a pump the following must be taken into
account:
• Required flow rate and pressure at the point of use.
• Pressure loss as a result of height differences
(Hgeo). • Friction loss in the pipework (Hf). 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.
• NPSHR value.
For calculation of the NPSHR value, see "Minimum
inlet pressure - NPSHR" on page 23.
P2 2/3
NPSH
0 100 200 300 400 500 600 700 800 Q [l/min]
Eta
[%]
80
60
40
20
0
TM01 4305 3700
Efficiency
Before determining the point of best efficiency the
operation pattern of the pump needs to be identified.
Is the pump expected always to operate at the same
duty point, select an MTR pump which is operating at a
duty point corresponding to the best efficiency of the
pump.
p
[kPa]
2000
1600
1200
800
400
0
H
[m]
240
220
200
180
160
140
120
100
80
60
40
20
0
0 100 200 300 400 500 600 700 800 Q [l/min]
0 10 20 30 40 Q [m³/h]
Fig. 22 Example of an MTR pump’s duty point
As the pump is sized on the basis of the highest
possible flow, it is important always to have the duty
point to the right of the optimum efficiency point (see
fig. 23, range with check mark). This must be
considered in order to keep efficiency high when the
flow drops.
eff
P2
[kW]
2.4
1.6
0.8
0.0
NPSH
[m]
8
6
4
2
0
-8
-7
-6
-5
-4
-3
-2
-1
-2-1
-1-1
Fig. 23 Best efficiency
MTRE 32
MTR,
Hz 60
ISO 9906 Annex A
1/1 P2
Eta
P2 2/3
0 100 200 300 400 500 600 700 800 Q [l/min]
0 100 200 300 400 500 600 700 800 Q [l/min]
Optimum efficiency point
NPSH
Eta
[%]
80
60
40
20
0
Dutypoint
Best
efficiency
US GPM
TM01 4305 3700
TM03 4874 3206
21
MTR(E)