On Mon, 27 Oct 2008 08:16:44 +0000, Rod wrote:

There's a white plastic pipe between the oil tank and the boiler. I
want to clip on a flow meter to measure the oil actually being
consumed at any one moment. Is there such a device?

Are you sure that is a plastic pipe - rather than a copper pipe with a
plastic coating?

I think he will find it;s is plastic coated copper. Plastic pipe
containing a flammable liquid in a fire ...

Anyway I doubt very much that a clip on flow meter exists. I can't think
of any physics that would allow the measurement of the flow of a
homogeneous fluid without something actually in the that fluid. There
*might* be something, maybe based on doppler, but I don't think that would
work without something in the fluid for the waves to bounce off(*). I
doubt any such solution would be cheap. Pressure variation across a
venturi? Would need the pipe to be cut to insert the venturi, not clip on.

Most cheap flow meters have a little paddle in the path that rotates with
the flow and you count the rotations over time, this again precludes the
requested clip on feature.

(*) Works for blood as blood has lots of bits, mainly red cells, floating
about in it for the waves to bounce off.

--
Cheers
Dave.