2.
OPERATION
The detector tube system is based on the following working principle. A precisely defined
volume of sample air is drawn through the detector tube. The detector tube contains the sensing
chemical, which reacts with the impurity gas in the sample air and produces a coloured stain in
the sensing chemical. The length of the coloured stain measures the impurity gas concentration
in ppm on the tube scale. The measurement involves the following steps.
2.1
Inspect the pump as described in section 3.
2.2
Break both ends of the tube using tip cutter.
2.3 Insert one end of the tube securely in the rubber tube connector ensuring that the arrow
on the detector tube points towards the pump.
