Copyright
2001
Almost
all other leak detection systems sense materials INDIRECTLY. That is,
they detect an event caused by a leak instead of the leak itself. A float switch
sensor, for example, detects a movement of the component's electrical contacts
which are actuated by movement of the float itself. Movement of the contact,
of course, may or may not be a leak. The same is true of capacitance measuring
2-wire cable systems (TDR [Time Domain Reflectometry] technology). These systems
detect only a change in capacitance level and then try to evaluate this change
with a somewhat sophisticated computer program. However, a change in capacitance
can be caused by a re-positioned cable, a change in moisture level, corrosion
at a connector, and a host of other factors. The control module is then left
with the near impossible task of sorting out a leak or a continuity failure
from some other event which causes a capacitance change.
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;)