Grundfos DMH 251 Installation And Operating Instructions Manual page 9

Pump type
Single pump Double pump
DMH 213-10 DMH 213-10/213-10
DMH 291-10 DMH 291-10/291-10
DMH 46-16 DMH 46-16/46-16
DMH 97-16 DMH 97-16/97-16
DMH 136-16 DMH 136-16/136-16
DMH 166-16 DMH 166-16/166-16
DMH 202-16 DMH 202-16/202-16
DMH 276-16 DMH 276-16/276-16
DMH 255
DMH 194-10 DMH 194-10/194-10
DMH 270-10 DMH 270-10/270-10
DMH 332-10 DMH 332-10/332-10
DMH 403-10 DMH 403-10/403-10
DMH 550-10 DMH 550-10/550-10
DMH 257
DMH 220-10 DMH 220-10/220-10
DMH 440-10 DMH 440-10/440-10
DMH 575-10 DMH 575-10/575-10
DMH 750-4 DMH 750-4/750-4
DMH 770-10 DMH 770-10/770-10
DMH 880-10 DMH 880-10/880-10
DMH 1150-10 DMH 1150-10/1150-10
DMH 1500-4 DMH 1500-4/1500-4
* l/h per dosing head; double the capacity for double pumps.
The pump can be operated in the range between
Note
10 % and 100 % of the maximum dosing capacity.
6.4.1 Accuracy
• Dosing flow fluctuation: smaller than ± 1 %
• Linearity deviation: ± 1 % of the full-scale value (for water with
a fully deaerated dosing head).
6.4.2 Inlet pressure and counter-pressure / suction lift
Maximum inlet pressure
Pump type
DMH 251
DMH 252
DMH 253
DMH 254
DMH 255
DMH 257
Minimum counter-pressure at the discharge valve of the
pump
Pump type
DMH 251
DMH 252
DMH 253
DMH 254
DMH 255
DMH 257
50 Hz
Max.
Q* p max. stroke
rate
[l/h] [bar] [n/min]
213 10 112
291 10 153
46 16 26
97 16 54
136 16 75
166 16 92
202 16 112
276 16 153
194 10 54
270 10 75
332 10 92
403 10 112
550 10 153
220 10 28
440 10 56
575 10 73
750 4 73
770 10 98
880 10 112
1150 10 146
1500 4 146
[bar]
8
8
5
5
0.8
0.8
[bar]
2
2
2
2
2
2
60 Hz
Max.
Q* p max. stroke
rate
[l/h] [bar] [n/min]
255 10 134
— — —
55 16 31
116 16 65
163 16 90
200 16 110
242 16 134
— — —
233 10 65
324 10 90
398 10 110
484 10 134
— — —
264 10 34
528 10 67
690 10 88
900 4 88
924 10 118
1056 10 134
— — —
— — —
A positive pressure difference of at least 2 bar is
required between the suction valve and the
discharge valve in order for the dosing pump to
operate correctly.
Note If the total counter-pressure (at the dosing point)
and geodetic height difference between the
suction valve and the dosing point is less than
2 bar (20 m WC), a pressure-loading valve must
be installed immediately before the dosing point.
100 Hz
Max.
Q* p max. stroke
rate
[l/h] [bar] [n/min]
— — —
— — —
92 16 52
193 16 108
271 16 150
— — —
— — —
— — —
387 10 108
540 10 150
— — —
— — —
— — —
440 10 56
880 10 112
1150 10 146
1500 4 146
— — —
— — —
— — —
— — —
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