7
10.0 Technology
The LeakDetectormeasurement is basedon thermal conductivity comparisons between the probe air and a reference air. The
device employs a dual thermistor technologywhichmeasures the ratioof [probe]:[reference] heat exchange values anddis-
plays the results on anLED scale (Figure 4).Under ideal operating conditions, a ratioof 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 indicatedby a single redor yellowLED light is generally insufficient topositively identify a gas leak. Small to
moderate leaks are reliably indicatedwith four redLED lights, larger leaks are indicatedwith all redLED lights or yellowLED
lights lit and the continuous alarm is audible.
LEFT:
Dual analysis is achievedwithheater
elements positioned in separate flow chambers.
RIGHT:
Probe and reference air streams are
simultaneouslymonitored for thermal
conductivity. Differences in air composition
are indicatedby differences in the heater
element currents.
Figure4
Schematic layout of the LeakDetector technology.
