BTG Mutek PCD-05 Smart, Руководство по эксплуатации

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© BTG Operation Manual Mütek
TM
PCD-05, September 2017 35
V. Measuring
5.6 Preparing the instrument
• Start the Mütek™ PCD-05 according to:
- Version Light, see chapter 4.6.1, page 27
- Version Smart, see chapter 4.6.3, page 28
• Clean the measuring cell and the displacement pis-
ton (see 7.1.2 "Cleaning the measuring cell", page
53).
5.7 Sample preparation
For stock systems including both colloidally dissolved
material and solid particles, different ways of sample
preparation will give different data on the charge condi-
tions prevailing in a sample (see 4.4.3 "Sample specifi-
cation", page 24).
Generally speaking, results are only directly com-para-
ble if the samples are prepared in an identical manner.
Test results obtained for samples of the same kind but
which were treated by different methods may yield addi-
tional information about, e.g., the charge conditions of
solids.
In each case, quantitative sampling must be ensured to
obtain reproducible values.
5.7.1 Filtration
To separate larger solid particles from a sample, a whi-
teband filter is normally used. However, this may falsify
results because polyelectrolytes tend to be adsorbed at
the filter paper. We therefore strongly advise against
using paper filters.
The use of ceramic filters by comparison is normally
problem-free.
5.7.2 Centrifugation
The centrifugation period must be identical for all
samples.
5.7.3 Screening
In the majority of cases, it will be sufficient to separate
long fibres and larger particles by means of a nylon
screen.
Quick and reproducible sampling is achieved by immer-
sing a Mütek™ filtration beaker with screen in the
sample and removing the supernatant liquid with a mea-
suring pipette.
Fig. 5-1 Screening of samples
Designations
1 Rising measurable sample
2 Original sample, e.g. thick stock, coated broke
3 Filtration beaker with 300 µm screen
1
2
3