The 821S has ten identical capillaries and a precision balance regulator. The span gas can be selected to flow through a number of those capillaries with the diluent flowing through the remainder, to produce a ratio. Many types of gas analyser are inherently non-linear due to the physical nature of the analysing technique. Photometric analysers (NDIR, NDUV, FTIR / spectrophotometers) need to be linearised before they leave the factory and then at regular intervals during service. Other more linear analysers will also need to be checked for linearity periodically whilst in service. This should be part of the QA/QC regime. Also known as a gas blender or gas mixer.
FID: the VOC emissions monitoring reference method – for over 50 years!
The Flame Ionisation Detection (FID) method was first developed in the 1950s for the laboratory analysis of organic chemicals. Later, when environmental regulations began to limit the emissions of volatile organic chemicals (VOCs) in the 1970’s and 1980’s, the FID method was adapted for emissions monitoring. Signal Group was one
09/04/2025
