At 14:52 01/11/99 +1100, James Cameron wrote:
>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.

if you can make the outlets the flow limiting part, and the flow speeds
leading to them are not too high, and you can keep the pressure constant
(where you would put your flow measurement), then each outlet gets constant
flow, only depending on the size of the outlet. adjustments on one outlet
wouldn't affect the flow in other outlets. the error in that would be the
loss of pressure along the line from the constant pressure to the outlet
(which depends on the flow speed and the cross section). the ants would
still make an error, but maybe small.

otherwise i don't know about "cheap" non-professional ways to measure flow.
paddle-wheels, measuring (flow speed depending) cooling of a heated
resistor, ... depends on your mechanical skills, amount of fiddle-time you
want to spend :-)


>"Specialisation is for insects." -- Robert Heinlein.

some of them are pretty universal ;-)

ge