Combustion Procedure; Cleaning The Decomposition Vessel; Halogens And Decomposition; Care And Maintenance - IKA AOD 1.1 Mode D'emploi

Combustion procedure

For the decomposition vessel charging procedure with fuel sam-
ples and the general procedure for performing combustion plea-
se refer to the operating instructions for the IKA AOD 1 system.

Cleaning the decomposition vessel

After each combustion the condensate has to be cleaned from
all of the parts of the decomposition vessel which come into
contact with the combustion products. It suffices to wipe out
the parts with an absorbent, non-fibrous cloth. Combustion
residues in the crucible, e.g. carbon black or ash are removed
in the same manner. The decomposition vessel may not be
mechanically cleaned under any circumstances if it is not capa-
ble of being cleaned in the manner described (e.g. due to burn-
in or pitting).
In such cases please contact your competent service center or
send in the decomposition vessel to the factory for inspection
and cleaning.

Halogens and decomposition

Decomposition vessel AOD 1.1 is obtainable in a modified
form for determining halogens and sulfur. This means that the
inner surfaces and the fittings of the decomposition vessel are
catalytically activated by means of a patented procedure.
Parts thus treated are recognizable because of their opaque, tar-
nished and partly spotty surfaces. This appearance of this surfa-
ce is intentional and should not be confused with traces of wear.
This state is important for the following analysis and may not
be treated with brushes or other hard materials.

Care and maintenance

The work described in the following may only be performed by
personnel with professional training or IKA.
All work on the fittings of the decomposition vessel require a
leak test and new pressure testing.
Furthermore, reference is made to the regulation for pressure
vessels 97/23/EC.
Replacing the ignition wire
The AOD 1.1 decomposition vessel is equipped with a fixed igni-
tion wire. Since the ignition wire is subjected to a high degree of
material stress during combustion, it should be replaced after
about 100 tests at the latest. However, this largely depends on
the type of samples fired.
• Unscrew the upper hexagonal nut (item 11) on the ignition
electrode (item 5) or the crucible holder (item 12) using a double
open ended spanner SW 5,5 which is included in the delivery
quantity.
Replacing the ignition electrode
The ignition electrode has to be replaced if it has become worn
as a combustion in the decomposition vessel.
• Open the decomposition vessel as described under
„Opening the decomposition vessel".
• Take hold of the complete cover unit.
• Remove the ignition wire
• Unscrew the hexagonal nut (item 11) in a counterclockwise
direction using the double open ended spanner (SW 5,5) while
firmly holding the ignition electrode (item 5). Screw the hexago-
nal nut completely off of the ignition electrode and put it aside for
later assembly.
• Pull the ignition electrode out of the cover. Make certain that
the insulating bushing (item 8) and the bearing bush (item 9) are
removed with the electrode. Clean both parts if required.
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