Grundfos ALLDOS KM 251 - Accuracy; Admission Pressure and Counterpressure; Suction Height

KM 251 en General
V1.0 7
* l/hr per dosing head; double the capacity for double pumps.
Note
The pump can be operated in the range between 10% and 100% of the maximum
dosing capacity.
1.2.3 Accuracy
1.2.4 Admission Pressure and Counterpressure / Suction Height
Maximum admission pressure at the suction side [bar]
Minimum counterpressure at the pressure valve of the pump [bar]
Note
A positive pressure difference of 2 bar min. is required between the suction valve
and the pressure valve in order for the dosing pump to operate correctly. If the total
counterpressure (at the dosing point) and geodetic height difference between the
suction valve and the dosing point is less than 2 bar (20 m WS), a pressure
retention valve must be installed directly in front of the dosing point.
Maximum counterpressure* [bar]
*Observe the maximum permissible temperatures
251-11 251-11/2 11 25 63 13 25 75 22 25 126
251-17 251-17/2 17 25 96 20 25 115 — — —
251-21 251-21/2 21 25 120 — — — — — —
Type 50 Hz 60 Hz 100 Hz
Singlepump Doublepump
Q*
[l/h]
p max
[bar]
stroke
value
[n/min]
Q*
[l/h]
p max
[bar]
stroke
value
[n/min]
Q*
[l/h]
p max
[bar]
stroke
value
[n/min]
Dosing flow
fluctuation
smaller ± 1 %
Linearity
deviation
±1 % of the full-scale value (for water with a fully deaerated
dosing head)
Type [bar]
KM 251 8
Type [bar]
KM 251 2
Type
Singlepump Doublepump
p max
[bar]
251-2,4 251-2,4/2
10
251-5 251-5/2
251-13 251-13/2
251-19 251-19/2
251-24 251-24/2
251-2,3 251-2,3/2
16
251-4,9 251-4,9/2
251-12 251-12/2
251-18 251-18/2
251-23 251-23/2
251-2,2 251-2,2/2
25
251-4,5 251-4,5/2
251-11 251-11/2
251-17 251-17/2
251-21 251-21/2