"Larry" wrote in message
...
"Franz Eckert" wrote in
. dk:

Maybe some of you gurus have an inexpensive idear of how to make a
flow meter that can measure the usage af gas to the engines. I don't
really care if it is analog or digital, as long as i can built it
myself :-)



The medical profession has a clear plastic flowmeter that's about 3" in
diameter with a red ball that the fluid running through it rotates around
the tube. It's a positive flow meter in that the ball just fits the round
tube and the tiniest flow of liquid shows up as a rotation of the ball. I
have no idea where you'd get it, but I'm sure any nurse or hospital supply
person could point you to the right company.

It would be very simple to put a light on one side of this tube and a
photocell on the other (OK, IR LED and photo IC is more complex and up-to-
date). Every time the ball comes around the loop, it would cut the light
so you could TIME the ball's rotation around the loop, which on the tube
is
calibrated in cc/hr or minute for the nurse to count. The time measured
would be easily converted to litres/hour or gallons/minute for your
display. The pulses could simply be fed to a serial port on a PC or
notebook already in use with a simple program monitoring the port's
data-in
and using the PC's timer functions.

How's that?....(c;

If you are talking about the Bel-Art flow indicator they are not really
positive displacement. It takes a water flow of 50mL/minute (maybe 35 for
diesel) before they start moving and they spin at different rates in the
horizontal position than vertical.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com