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11 Technical aspects
11
Technical aspects
11.1
Technical notices
Heavy gas
When working in probe holes (GAS-MEASURING mode), you
may find that carbon dioxide CO
2
(heavy gas) overlays the
methane CH
4
(light gas). In this event the instrument will indicate
no concentration (0 vol.%).
If it is carbon dioxide (monitoring over the CO
2
measurement
range), we recommend the use of a CO
2
filter (accessory kit) to
suppress the heavy-gas component.
High CO
2
concentrations (from approx. 5 vol.% on) will have a
damaging effect on the CO
2
sensor.
Gas injection/blanketing
If you wish to carry out a gas injection (an increase in concentra-
tion to 100 vol.%) or blanketing (a reduction in concentration to
0 vol.%), select
GAS-MEASURING mode
(device variation 1)
with the
pump key (
device variation 2) (cf. section 9.5: Setting
the 100 vol.% range).
Only in this mode can measurement be reliably monitored.
Probe hoses
The rule of thumb is: the concentration display is delayed by about
1 second per metre of hose.
Always use SEWERIN probe hoses 1 m, 2 m or 6 m long. The
maximum length of 12 m should not be exceeded.
Sensitivity of the thermal-shading sensor
The sensor sensitivity of the thermal-shading sensor can be falsi-
fied under the following conditions:
an atmosphere low in oxygen will lead to the reduction of the
value displayed (the sensor will choke).
the device may not be operated in an oxygen-enriched atmos-
phere due to the explosion protection.
Summary of Contents for EX-TEC Combi
Page 1: ...Operating Instructions ...
Page 3: ...Illustration EX TEC Combi EX TEC Combi Device variation 1 Device variation 2 EX TEC Combi 100 ...
Page 5: ...Operating Instructions 15 06 2005 V2 X 103401 en EX TEC Combi ...
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