Gerhard Fiedler wrote:
> maybe you can hinder the ants crawling up? something like a "siphon"
> (german, didn't find it in the dictionary -- goes down and up again, so
> that there's always water in the bend) maybe, in some central places in
> the main pipes.

Australian conditions.  Temperatures up near 40 degrees centigrade are
fairly normal, agricultural distribution pipes are matt black PVC, the
pipes may boil themselves dry on a hot day and a bend containing water
would probably attract ants anyway.  ;-)

> difficult to measure volume flow if the active cross section of the
> pipe is not known.

Good point.  I was thinking of a distribution layout like this;

Water Supply --> Filter --> Flow Measurement --> Valves

                                                |       |       |
                                                v       v       v
                                                Filters
                                                |       |       |

First filter is to remove things from the water that would annoy the
flow measurement and valves.  Last set of filters after the valves would
be to prevent ants from crawling back into the valves and flow
measurement.

The other "problem" is that after the valves for regions of garden or
orchard the distribution pipes go to outlets of various sizes, which are
adjustable.  Gotta figure out how to rig it so that an adjustment of one
outlet doesn't affect the flow from another.

--
James Cameron                                      (cameron@stl.dec.com)

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