A polymeric optical fiber intensity based level sensor
was presented, being an appropriated solution to be used
into highly flammable liquids reservoirs without risk, such
in oil piping or fuel tanks. A suitable sensitivity for the tested
versions was obtained; the number of grooves and the
distance between them define the sensing resolution. Still,
the sensor sensitivity and resolution can be tailored for
several applications. Although several electronic or/and
optical sensors had been already reported previously with
higher resolution on the level monitoring, comparing to
the reported solution, this POF based sensor present quite
a few advantages on medium to large containers level
monitoring, such on the simplicity, production and interrogation
cost.
Three sensor versions were implemented and
experimentally characterized, with different groove depths
and spacing, demonstrating the sensor adaptability to the
container dimensions. For these versions, a sensitivity
based on the variation relatively to the initial transmitted
optical power of 1.48%, 2.20% and 2.60% was detected per
each liquid fulfilled groove.
We have implemented a level sensor, based on the procedure
described, with possible application in, among
many, the monitoring of groundwater tablet levels, soil
moisture monitoring in agriculture and liquid level in
tanks of flammable substances.