Ametek Thermox 2000 ATEX Series User Manual page 14

The Combustibles Detector
The Combustibles Detector is a dual element device; the elements differ
only in that one is coated with a catalyst. The catalyst causes oxidation to
occur at a lower than normal temperature. The temperature of the cata-
lyzed element changes as the combustible mixture burns. The temperature
change causes the resistance of the catalyzed element to change. The resis-
tance change is interpreted by the microprocessor and the corresponding
combustibles reading is displayed.
The Thermox catalytic combustibles detector will detect combustible gas
present in a sample. The sample must, however, contain enough oxygen to
fully burn the combustible present. The combustibles detector responds to
all unburned combustibles gases, such as CO and H . We recommend us-
2
ing an even mixture of CO and H as the combustibles component within
2
your span gas, although you can also use all CO if needed.
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