Bob Ammerman wrote:
>
> Another thought was brought on by the response below.
>
> When pipes are run together in a group the 'ping' would tend to couple to
> the other pipes in the group and propogate in the same direction. This would
> fool a time-based differential probe system. Therefore, I think you'll also
> need to do an amplitude comparison between the two probes so that you could
> differentiate by either amplitude or timing.
>
> With a little experience, I imagine this would be a useful tool to greatly
> aid manual tracing of the pipes. I don't expect it would work too well
> across the entire length of the plant, though.

I think i'd try connecting a low-ish freq ac
(like 400Hz) to the far end of the pipe, and test
with a magnetic pickup (like the phone ones at
radio shack) waving it near all the pipes at the
end where they all come together. Telecom companies
use a similar system with long wires, it works
pretty well. Even if the pipes are joined in
places by the clamps, they are unlikely to have
as strong a signal as the "one" pipe.
A small ac coupled amp and a mV meter would
give a good indication, with an audio tone as
well. I have one of the telecom type tracers,
it's very simple.
-Roman

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