Tanker Gas Instruments

Gas IndicatorsMeasurement of Hydrocarbon concentrationCatalytic Filament Combustible Gas indicator (CFCG) is used to measure HC gas in air at concentration below LFL. ( % LEL)Non catalytic heated filament gas indicator and Refractive Index meter used for measuring HC gas in excess of LEL or oxygen deficient (inerted) atmosphere.

Catalytic Filament Combustible Gas indicator (CFCG) Sensing element is catalytic metal filament heated by an electric current.When a mixture of HC in air is drawn over the filament, gas oxidises on the hot filament and makes it hotter.This increases the resistance and change of resistance provides a measure of concentration of HC gas in the mixture.

Catalytic Filament Combustible Gas indicator (CFCG) Works on Wheatstone bridge with sensor element forming one arm of the bridge.Deflection is shown on a scale calibrated to read 0 100 % LEL.Some instrument may have extended range of 1-10% LEL.Follow Manufacturers detailed instructions for the correct use and calibration.

Catalytic Filament Combustible Gas indicator (CFCG) If concentration of HC is more than about twice the LEL, there is insufficient oxygen in the mixture to burn the HC gas completely.Due to above, needle will point to max reading on the scale and falls back to reading near zero.Continuous observation of the needle is necessary to avoid overlooking this kind of response.For the same reason, this instrument does not give reliable reading in inerted or oxygen deficient atmosphere.

Catalytic Filament Combustible Gas indicator (CFCG) - Checks Check instrument prior use in fresh air.Also check after renewing filament.Calibrate as per manufacturer instructionsCheck sensing lines for any leakagesLeak test by pinching aspirator if fitted.Only instruments fitted with flashback arrestors in inlet and oulet of detector filament should be usedNo filters other than cotton filters to be used in inlet side.Water trap or water absorbent material may be used if gas is very wet.