Atest Gaz Sigma SmArt, Руководство пользователя

Страница: 63 / 84

www.atestgaz.pl
1 Detected substances
NDIR sensors (non-dispersive infra-red sensor), commonly called IR sensors, are used for measuring gases
concentrations which have ability to absorb the electromagnetic spectrum in the infra-red range:
organic compounds particularly methane,
carbon dioxide,
other (e. g. carbon monoxide, nitrogen compounds, ammonia, CFC, SF
6
).
Those sensor do not detect hydrogen.
2 Principle of operation
NDIR sensors operate based on the phenomenon of absorption of infrared (IR) radiation wave of a specified
length by specific gases. If there is an appropriate gas in the path of this radiation, it will absorb part of this
radiation. The sensor consists of a source of IR radiation and a detector for measuring its intensity. The
measured gas flows between these elements. The decrease in intensity of the IR beam is a measure of the
gas concentration.
3 Impact of environmental conditions
Never exceed the rated operating parameters of the detector. These parameters can be
found in the detector calibration certificate.
The detector must be used in accordance with the provisions in the User's Manual.
3.1 Composition of the controlled atmosphere
Due to the principle of operation, detectors equipped with NDIR sensors can work in a variety of
atmospheres – including those deprived of oxygen.
3.1.1 Impact of the presence of a working gas or other reaction gas
NDIR sensors are characterized by relative selectivity, e. g.:
in principle, they will not be selective within the group of organic compounds,
they will be selective for gases with different absorption energy in the infrared band.
The method of measuring concentrations using NDIR sensors (in particular in relation with organic
compounds), is a method alternative to catalytic methods wherever:
the presence of gas in the atmosphere may be prolonged or continuous,
there is a need to measure the concentrations above 100% LEL (to 100% of volumetric
concentration),
there is a need to measure the concentration of organic compounds in a low- or zero-oxygen
atmosphere,
there is a need to measure the concentration of flammable gases in the air, but the presence of
gases interfering or destructive for the catalytic sensor does not allow the use of catalytic sensors.
Atest-Gaz A. M. Pachole sp. j.
ul. Spokojna 3, 44-109 Gliwice, Poland
VAT No.: PL 9691433231
tel.: +48 32 238 87 94
fax: +48 32 234 92 71
e-mail: contact@atestgaz.pl
p. 2/3 Appendix: PU-Z-064-ENG R01
•