Danfoss H1 Axial Fact sheet
Fact sheet
AB-QM f low checker DN 40-250 and AB-QM 4.0 DN 15-20 Verifying the flow on AB-QM valves
Flow verif ication |
To verify that an installation functions according |
in an installation |
to the design specif ications checking only the |
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most critical valve in the installation is needed |
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(see f igure 1). |
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The AB-QM maintains a constant differential |
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pressure over the valve and any excess pressure |
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will automatically be throttled. If there is not |
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enough differential pressure the valve cannot |
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reach the set f low. |
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The valve that is furthest away from the pump or |
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the valve in the circuit with the highest resistance |
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has the lowest available differential pressure, so |
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if this critical valve has enough pressure it means |
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the other valves will also function properly. |
Important:
To get a useful measurement the installation should run on full load, so all actuators in the installation should be opened fully. This
ensures that you are measuring under the most unfavorable circumstances. The AB-QM’s will have more differential pressure available when the installation is working on partial load.
To get useful measurement the commisioning zone should run on full load, so all actuators in the installation should be opened fully. Please check if coincidence factor was taken into consideration.
Fig. 1
Method of verif ication
AB-QM DN40-250
Measure the differential pressure across the whole valve.
The test plugs are placed in such a way that differential pressure p1−p3 (Δp) over the valve is measured (see f igure 2).
If the measured value is below 30 kPa then there is not enough differential pressure available for the AB-QM to function properly. If the measured value is above 30 kPa then the AB-QM has enough differential pressure available and the f low is according to the setting (see f igure 3).
Setting the f low
DN 40-100: 1 turn=10 % DN 125-250: 1 turn=5.0 %
Note: for more information about setting procedure please refer to instructions
Method of measurement
AB-QM DN40-250
AB-QM 4.0 DN15-20
Measure the differential pressure across the control valve.
The test plugs are placed in such a way that p1−p2 is measured (see f igure 2).
Therefore the measured differential pressure can be used to calculate the f low directly. It’s necessary to use the table that was derived from statistical measurements
Since the measurements across the measuring points are inf luenced by the dynamic pressure, turbulences, f low patterns, internal tolerances, setting accuracy and accuracy of the measuring
equipment we believe that the total accuracy of the measurement is lower than performance of the valve.
Therefore we recommend not to adjust the setting when the results are within 10 % of the expected f low.
Calculating the f low
ΔpCv = p1−p2
Q kvCv 
pCv
For kvCv values see tables in figure 4 and 7
© Danfoss | 2022.01 |
AM322356127863en-000102 | 1 |
Fact sheet |
AB-QM f low checker DN 40-250 and AB-QM 4.0 DN15-20 |
AB-QM 4.0 DN 15-20
Flow direction
p1−p2 |
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Δp=p1−p3 |
∆pmin |
DN 15-20 |
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Fig. 2 |
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Fig. 3 |
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Presetting |
DN 15 LF |
DN 15 NF |
DN 15 HF |
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DN 20 NF |
DN 20 HF |
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s (%) |
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kvCv (m3/h) |
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10 |
0.0411 |
0.145 |
0.2588 |
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0.180 |
0.4152 |
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12.5 |
0.0531 |
0.180 |
0.34 |
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0.240 |
0.5346 |
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15 |
0.0659 |
0.215 |
0.4085 |
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0.300 |
0.6472 |
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17.5 |
0.0779 |
0.250 |
0.4754 |
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0.360 |
0.7515 |
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20 |
0.0890 |
0.285 |
0.5426 |
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0.420 |
0.8558 |
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22.5 |
0.1000 |
0.320 |
0.6095 |
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0.490 |
0.9602 |
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25 |
0.1111 |
0.355 |
0.6767 |
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0.560 |
1.0645 |
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27.5 |
0.1221 |
0.390 |
0.7502 |
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0.630 |
1.1688 |
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30 |
0.1332 |
0.425 |
0.8237 |
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0.700 |
1.2815 |
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32.5 |
0.1442 |
0.460 |
0.8969 |
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0.770 |
1.3951 |
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35 |
0.1570 |
0.495 |
0.9705 |
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0.840 |
1.5023 |
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37.5 |
0.1686 |
0.530 |
1.0407 |
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0.910 |
1.5981 |
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40 |
0.1796 |
0.574 |
1.1076 |
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0.980 |
1.6939 |
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42.5 |
0.1907 |
0.618 |
1.1748 |
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1.050 |
1.7896 |
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45 |
0.2018 |
0.662 |
1.2416 |
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1.120 |
1.8854 |
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47.5 |
0.2129 |
0.706 |
1.3165 |
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1.190 |
1.9812 |
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50 |
0.2245 |
0.750 |
1.3887 |
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1.260 |
2.0770 |
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52.5 |
0.2360 |
0.798 |
1.4579 |
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1.330 |
2.1728 |
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55 |
0.2476 |
0.847 |
1.5274 |
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1.400 |
2.2247 |
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57.5 |
0.2592 |
0.895 |
1.5966 |
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1.470 |
2.2582 |
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60 |
0.2707 |
0.943 |
1.6657 |
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1.540 |
2.2916 |
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62.5 |
0.2823 |
0.992 |
1.7342 |
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1.610 |
2.3251 |
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65 |
0.2939 |
1.040 |
1.79 |
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1.665 |
2.3587 |
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67.5 |
0.3054 |
1.088 |
1.846 |
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1.720 |
2.3972 |
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70 |
0.3172 |
1.135 |
1.902 |
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1.775 |
2.4356 |
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72.5 |
0.3293 |
1.183 |
1.958 |
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1.829 |
2.4741 |
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75 |
0.3414 |
1.230 |
2.0139 |
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1.884 |
2.5126 |
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77.5 |
0.3535 |
1.278 |
2.0835 |
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1.939 |
2.5619 |
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80 |
0.3655 |
1.325 |
2.1364 |
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1.996 |
2.6122 |
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82.5 |
0.3765 |
1.373 |
2.1756 |
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2.054 |
2.6626 |
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85 |
0.3876 |
1.420 |
2.2172 |
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2.111 |
2.7245 |
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87.5 |
0.3986 |
1.455 |
2.2722 |
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2.169 |
2.7897 |
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90 |
0.4097 |
1.490 |
2.3343 |
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2.211 |
3.1346 |
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92.5 |
0.4226 |
1.525 |
2.398 |
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2.249 |
3.4703 |
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95 |
0.4367 |
1.560 |
2.4778 |
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2.288 |
3.5544 |
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97.5 |
0.4509 |
1.595 |
2.5298 |
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2.326 |
3.6422 |
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100 |
0.4650 |
1.630 |
2.6 |
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2.365 |
3.7300 |
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Fig. 4 The f low is according to setting if the calculated f low is in the range of ±10 % of the set flow.
2 | AM322356127863en-000102 |
© Danfoss | 2022.01 |
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