High carbon results are erratic:
Even if the filter may be brushed and cleaned in ultrasonic cleaner, someday will not be able to
be cleaned any more. Filters don’t last forever.
Clean the filter and make some analyzes again. Should the results still be erratic, replace it by a
new one.
Sulfur results are not repeatable::
When the Sulfur results are not stable, but the carbon results are good, there are two possible
reasons
– The magnesium perchlorate (anhydrone) is saturated.
Replace the complete contents of the glass tube after the corresponding furnace.
– There is sulphuric acid in the combustion tube of the resistance furnace. Replace the
combustion tube, see chapter “Replacing the combustion tube”
If the combustion tube (4) was in use for a very long time and many samples with high Sulfur
were analyzed, then sulfuric acid may build up in the rear-side of the combustion tube.
When the heated tube is removed together with the connector (5), a brown fluid can be seen in
the ceramic tube.
During the analysis, some SO
2
is trapped in this fluid, causing non
repeatable results. It is recommended to clean the furnace outlet tube.