21
C7010/12 0508
be checked for wear by an expert after each combustion operati-
on. The main sealing must be replaced if wear is evident.
•
Remove the main sealing (item 4) by using a suitable tool to
pry the O-ring out of the groove in the cover (item 2).
•
Pull the O-ring toward the side of the cover that is smaller in
diameter.
Make certain not to damage the cover with tool. This may cause
the decomposition vessel to leak. The sealing that has thus been
replaced may not be reused. Replaced the old sealing with a new
one from the set of O-rings.
•
The new sealing is also mounted on the side of the cover that
is smaller in diameter. Place the O-ring on one side the groove in
the cover.
•
Use your fingers to pull the O-ring over the edge of the cover
until it snaps into groove on its own.
Perform a leak test after the decomposition vessel has been
assembled.
(see capture “Leakage test”)
The leak test does not replace
pressure testing !
Replacing the crucible holder
The crucible holder must be replaced it if has become worn as a
result of the combustion operations.
•
Open the decomposition vessel as described under „Opening
the decomposition vessel“.
•
Remove ignition wire and ignition electrode as discribed befo-
re.
•
Unscrew the hexagonal nut (II
) adjacent to the inside cover of the
crucible holder in a counterclockwise direction using the SW 5,5
double open ended spanner.
•
Screw the crucible holder out of the cover.
Installation of the new crucible holder contained in the set of electro-
des with deflector is performed in the reverse order.
•
Check the decomposition vessel for escaping bubles of oxy-
gen.
The leak test does not replace pressure
testing !
Oxygen valve maintenance
The oxygen valve is used to fill and emptycthe decomposition ves-
sel. It is a non-returnable valve that only closes when the decom-
position vessel is full with oxygen.
The ignition electrode item 5 serves at the same time as a valve
piston. The sealing surface is in the cover of the decomposition
vessel. The O-ring sealing wears through use and because of
aggressive combustion gases, which means that the decomposi-
tion vessel may not be tight.
Check the sealings for wear in accordance with regular intervals
stipulated by the safety provisions. If the decomposition leaks
during combustion in the calorimeter the escaping oxygen may
damage the decomposition vessel and the calorimeter.
•
In order to replace the O-ring the ignition electrode must be
removed from the cover as described.
•
Remove the O-ring item 7 by first pulling the bearing bushing
(item 9) off of the ignition electrode and then removing the O-ring.
•
Place the new O-ring from the set of O-rings onto the ignition
electrode item 5 from above and then push the bearing bushing
item 9 until it again reaches the ignition electrode.
Make certain that the O-ring does not become damaged by sharp
edges.
After installation of the ignition electrode the bearing bushing is
teightened with the hexagonal nut item 6/11 in order to prevent it
from slipping out of place.
Replacing the main sealing
The main sealing item 4 is used to seal off the cover item 2 from
the bottom part item 1.
The main sealing and the sealing surface on the bottom part must
3017500b_C7010_7012_052008:C5010_12 09.06.2008 9:59 Uhr Seite 21
