8.3
Calibration on initial start-up
The metering pump is calibrated at the site to the flow rate of the
corresponding pump type at nominal pressure.
The corresponding flow rate and the nominal pressure is given in the
technical data in the operating manual.
We suggest to carry out the calibration of the pump at the first
commissioning again and to adapt it to the on-site operating and
ambient conditions.
We would like to point out that the flow rates stated in the technical data
were tested in the factory under ideal conditions (metering of water at
20 °C, short suction and metering lines, nominal back pressure, no
pressure-increasing valves in the metering line). The flow rates are highly
dependent on the viscosity of the metering medium, how large the cross
sections of the metering lines are and how long the metering lines are!
For these reasons, on-site calibration is absolutely necessary.
Fig. 81: Schematic layout: Calibration
– The volume of the measuring cylinder should be 1/50 of the metering
pump rate in litres/h.
– During the calibration process, the position of the suction tube may not
be changed.
– The calibration of the metering pump is only valid for the currently set
stroke length setting. Following a change in stroke length, the
calibration has to be performed again.
– Following calibration, the pump is ready for use.
Calibration variants:
n
Calibration via "volumetric measurement" of the pump.
n
Calibration by "weighing" the metered metering
medium.
n
Calibration using an oval gear meter 'OGM
137
Start-up
PLUS
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417102276 Rev. 5-02.2020