all i can think of is a capacitive detector.
that of course may not work if the fluid is
erratic, i guess you could also detect for
sudden changes. if its a glass tube that should do it.
then there is the optical method, but that involves
a complex twisted alignment .
induction is also another possible...
bubbles can cause electrical property changes that
can be used different ways.
also theirs the system we use where we have a
Sonic Transducer on a glass rod we in a boiler system
to detect levels and bubbles. we have it set so the
receiver will pick up its own signal if there is bubbles
or lack of water.. this works because the water acts as a
cushion to not allow the sonic to reach the other end.
the more dense the water is the less the tube vibrates.
of course this takes place on the high end of the sonic
there are many possible ways, i think they already make
devices that you can attached that are of a capcaitive
Thanks for the input, actually the tube carrying the liquid will probably be
copper and possibly stainless steel. under pressures of 125 to 275 psi.
There is a device on the market that has two sensors that attach to the tube
about 3 inches apart and the bubbles are detected and indicated as an