Oldham olct ir, Техническое руководство

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2
– Technical specifications
9
OLCTIR CH
4
calibré CH
4
: Interférence des principaux alcanes & alcools
0,0
10,0
20,0
30,0
40,0
50,0
60,0
70,0
80,0
90,0
100,0
0,0 10,0 20,0 30,0 40,0 50,0 60,0 70,0 80,0 90,0 100,0
Conc [% LEL]
Méthane CH4
Propane C3H8
Butane C4H10
Hexane C6H14
Nonane C9H20
Cy clohexane C6H10
Méthanol CH3OH
Ethanol C2H6O
% LEL CH
4
2.1 Interference of common gases on OLCT IR (CH
4
and HC)
Any organic molecule with at least one C-H bond except for acetylene can potentially be detected by the OLCT IR,
though the sensitivity varies.
Note the following:

Regardless the detector version, saturated hydrocarbons give a greater response than CH
4
;

The OLTC IR CH
4
is more sensitive to CH
4
and less sensitive to hydrocarbons than the OLCT IR HC;

With regards to the OLCT IR CH
4,
a signal of 20mA corresponds to 100% LEL CH
4
or 20% LEL C
3
H
8
(factor 5);

With regards to the OLCT IR HC, a signal of 6.4mA signals corresponds to 100% LEL CH
4
or 14% LEL
C
3
H
8
value (factor 7);

The OLCT IR HC is usually more suitable for the detection of saturated molecules such as alkanes,
alcohols, ketones, organic acids, esters and ethers.

The OLCT IR CH
4
is usually more suitable for the detection of unsaturated hydrocarbons such as alkenes
and aromatics with H-C bonds although they give less signal than CH
4
As an example, see below the response curves for common HCs (accuracy is +/-15 %).

OLCT IR CH
4
OLCTIR CH4 calibrated to CH4: Interference of the main alkanes and alcohols
Conc [% LEL]
Methane CH4
Propane C3H8
Butane C4H10
Hexane C6H14
Nonane C9H20
Cyclohexane C6H10
Methanol CH3OH
Ethanol C2H6O
% LEL CH4