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10.0 Technology
The leak detector measurement is based on thermal conductivity comparisons between the probe air and a reference air. The device employs
a dual thermistor technology that measures the ratio of [probe]:[reference] heat exchange values and displays the results on an LED scale
(Figure 4). Under ideal operating conditions, a ratio of 1:1 indicates identical air samples for both [probe] and [reference], and therefore, no
leak is present.
Because of slight differences in air temperature and/or humidity between the reference inlet (Figure 1) and the probe tip, a small response
indicated by a single red or yellow LED light is generally insufficient to positively identify a gas leak. Small to moderate leaks are reliably
indicated with 3 red or 2 yellow LED lights and
an intermittent beep. Larger leaks are indicated with all red or yellow LED lights lit and a
continuous audible alarm.
LEFT:
Dual analysis is achieved with heater
elements positioned in separate flow chambers.
RIGHT:
Probe and reference air streams are
simultaneously monitored for thermal
conductivity. Differences in air composition
are indicated by differences in the heater
element currents.
Figure 4:
Schematic layout of the leak detector technology.
