Q: How does it work?
A: The Pillar Point Electronics Universal Fluid Sensor (UFS) uses a miniaturized infrared (IR)
emitter and detector built into a tiny microprocessor-driven electronic circuit potted into
a fitting, as shown in the sketch. Two versions of the UFS are available:
the UFS-T and the UFS-AN. The UFS-T is a UFS mounted in a custom made tee and is designed for in-line
applications. The UFS-AN is a modified AN912-2D bushing and is designed for in-tank
applications. A clear, cylindrical cast acrylic prism is potted into the fitting in
contact with the fuel or other non-particulate bearing liquid.
The sensor works on the principle of internal reflection in the prism. Since the index
of refraction of the prism and air are very different, when the end of the prism is not immersed
in the liquid, the IR light is internally reflected back towards the IR detector. When the detector
"sees" the IR light, the output(s) of the circuit can illuminate a warning light (or activate other devices.)
When the prism portion of the sensor is immersed in the liquid, the refractive indices nearly match,
so IR light escapes from the prism and into fuel.
Q: What happened to the PPAv XFR line?
A: In February 2004, Facet changed the design of their 40171 fuel pump. This pump--used by many
builders of Amateur-Built aircraft--was controlled by PPAv's XFR-J fuel pump controller. The changes
made by Facet caused the XFR-J to no longer be able to sense the end-of-fuel condition and thus
automatically shut off the pump. While other PPAv fuel pump controllers could control other
Facet pumps (such as the XFR-K that controls the Facet 40105, 40106, and 40108), PPAv's core XFR
business was the XFR-J.
To overcome the problem, PPAv developed a new method of controlling the fuel pumps--virtually
any brand of fuel pump--by adapting our low fuel sensor to provide an end-of-fuel to the XFR (the XFR-SA).
But, since the XFR-SA required external sensing and since the XFR production was labor-intensive,
it no longer offered our customers good value for the money.
Thus, PPAv discontinued the product line and PPE does not have plans to revive it.
Thank You.
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