Note:
These settings may only be adjusted by trained specialist staff.
It is important to make sure that the measuring range from 1400 l/min (at
NW 76) is sufficient, i.e. there is still reserve capacity to adjust upwards.
A change of the scaling from 1400 l/min to 1600 l/min can be helpful in this
regard. This is achieved by providing the flow rate of 1400 l/min to 1600
l/min at 20 mA in the MAK controller. At the same time, the E5 tab in the
FLM must be set to a value between 84 and max. 96. This can only be
changed by a BARTEC BENKE service engineer.
Step 3:
Fine adjustment of bottle volume:
If the above adjustment has been carried out and the values tally then the
filled sample bottle volume can be aligned with the hose calibration factor.
An increase in the factor means that less will be put into the bottles because
the sampler controller assumes that the peristaltic pump will deliver more in
one revolution and that therefore fewer revolutions or steps are needed to
obtain the same volume.
If this value is also adjusted, the pumped volume of the sampler should be
about right, even with small quantities. If this is not the case, however, it is
necessary to check whether the maximum limits of the sampler are being
exceeded, especially with small quantities.
Accuracy of measurement
The pumped sample bottle volume is displayed on the MAK 3003, indicating
whether the sample which has been taken is representative or whether the
limits of the sampler have been reached (cf. 2.1). This value should normally
be equal to the sample bottle volume setting if the actual set quantity tallies
with the input quantity and if the ULTRASAMPLER system has been set
properly and is working correctly.
The intake process is not constant, however, but is subject to continual
changes in output and air content, therefore it is only possible to obtain an
approximate measurement. Another factor to bear in mind is that the change
in throughput is accompanied by a change in pressure and therefore the
hose calibration factor varies slightly.
The (pumped) sample bottle volume which is displayed should therefore be
regarded as a rough indication only. On account of the fact that the intake
process is not always constant (see above), the value can vary by about 10
% (approx. 2 - 3 ml) from the set sample bottle volume without affecting the
representativeness.
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