Re: Tank Depth

Hello Rich,


c. PVC pipe with end cap, must be absolutely water tight. Copper pipe in the middle that has an OD almost as large as the ID of the PVC pipe. Connect oscillator circuit to it. This forms a capacitor where the capacitance changes with the water level. This in turn changes the frequency but it won't be linear. Follow with a little F/V detection and you'd have a nice analog readout. Add a comparator that shuts off the pump below a chosen threshold.

Do you mean, the copper middle electrode is completely insulated from the
water? If that's all you need, you could paint it. How about a stainless steel rod inside a stainless steel tube, where the water is the dielectric
between these two - i.e., the level on the inside is the same as the level
on the outside.

That is, I'm thinking that the water goes up inside the capacitor tube,
but your description of an "absolutely water tight" construction makes
me wonder what you have in mind. ?:-/


Even rain water can be aggressive. When I lived in Europe there were times when I got rain in the eyes and they started buring. Same back east. Has gotten better though.

Paint, exposed metal, all that will rot over time. I have even seen steel corrode although it was sold as stainless. In an application like this ideally you need something that you can build and forget for a few years.

--
Regards, Joerg

http://www.analogconsultants.com
.

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