7
Maintenance
Current Maintenance Program
Thermo Scientific
EA IsoLink IRMS System for CNSOH Operating Manual
127
• To measure:
• To cool down the furnace:
If you do not want to perform any analysis
for about one day
(for example, over night), put the
instrument in stand-by condition, and set the oven temperature to
150 °C
.
• If you do not want to perform any analysis
for more than one week
, put the instrument in
stand-by condition, cool down both furnaces and oven to ambient temperatures.
• If the pyrolysis unit has not been in use
for a long time
or if it was
off
, heat the column to a
temperature of
190
o
C
for at least
24 hours
. Make sure to maintain a flow through both
separation columns during baking out
• Always watch the background of the masses
28
and
40
. If the values exceed those you were used to,
perform a leak test. A small leak will crack the ceramic tube, and after a while the glassy carbon
reactor, too.
• After around
400
measurements (depending on size and type of the samples) clean or replace the
graphite crucible as described in the
“To clean/replace the graphite crucible,”
operating sequence.
After cleaning the crucible may be used again. See also reactor maintenance.
Replacing the Gas Chromatographic Column
The instrument rarely requires the gas chromatographic column replacement, however, in case, operate
according to the following operating sequence.
To replace the gas chromatographic column in the GC oven of the EA.
1. Open the instrument right door and remove adsorption filters from their securing clips.
CAUTION
As the lifetime of the furnace heater is limited, do not heat it to higher temperatures
than necessary. Put it to a lower standby temperature, when not in use for several days, or turn it off
for longer idle times.
Type of analysis
Suggested operating temperature
Oxygen of organic samples
1325 °C - 1350 °C
Oxygen of inorganic samples
1450 °C
Hydrogen of organic samples
1450 °C
Hydrogen of inorganic samples
1450 °C
Water (sample amount > 1
μ
L)
1400 °C
Note
To replace the GC column in the ramped GC oven, please refer to the Ramped GC Oven
Operating Manual.
Material Required
Open end wrenches for the column fittings
Note
According to the instrument configuration, there can be one or two adsorption filters in
the detector compartment.