Yokogawa GC1000 Mark II Process Gas Chromatograph Manuel d'utilisateur télécharger pdf (Page 19)

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IM 11B03A03-01E 3rd Edition : Aug. 23. 2006-00

(2)Flame Ionization Detector (FID)

The FID utilizes the phenomenon that carbon molecules in the measured component

(hydrocarbon) are ionized in a hot hydrogen flame. That is, it detects the ionization current

which flows between electrodes to which a high voltage is applied. The ionization current is

proportional to the concentration of the measured component.

The FID is used to measure the component concentration of gases containing low concen-

trations of hydrocarbons.

F0104.EPS

Output

Ion collector coil

Hydrogen flame

Jet pipe (nozzle)

Carrier gas

Sampling gas

Hydrogen gas for combustion

Figure 1.4 Fundamental Principle of Flame Ionization Detector

(3)Flame Photometric Detector (FPD)

Figure 1.5 shows the structure of the FPD. As the sample gas containing a sulfur compo-

nent is led into the excess hydrogen flame, the component containing the sulfur atoms is

excited. The FPD detects the luminous intensity of the light emitted when this excited

component return to its base state using multiplier phototube and converts it to a voltage.

This voltage represents the concentration of the sulfur component in the measured gas.

The FPD can measure on the sulfur component with a high sensitivity of 1 ppm.

F0105.EPS

Photomultiplier tube

Hydrogen flame

Jet pipe (nozzle)

Carrier gas

Sampling gas

Air fo combustion

Hydrogen gas for combustion

Hydrogen gas

for combustion

Figure 1.5 Basic Configuration of Flame Photometric Detector

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 76 77

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Yokogawa GC1000 Mark II Process Gas Chromatograph Manuel d'utilisateur Page 19