The Closed Circuit Sieve

On March 26 we had our first successful build of something that looks vaguely like a closed circuit fountain. It leaks like a sieve, but we’re ignoring that part.

This is a proof of concept with a 100W pump, a fully built airtight bucket, a ½” main feed line to ⅜” tube feed line, and two ⅜” drain lines.

It turns out that when you push pressurized water through a 3/8″ tube and also try to drain it with an unpressurized 3/8″ tube, the drain can’t keep up with the feed line. These are the kinds of things one could calculate in advance, but sometimes seeing the mistake is more fun.

Water flow with this pump and the ⅜” feed was good and strong.

Feeding the pump line though the lid of the bucket is a PITA, it makes it really awkward to get the lid off.  We’ll try next with a bulkhead union on the side of the bucket so it can just be permanently installed.

The bucket concept is working well.  Here it is closed and ready to transport. Just plug in, fill with water, and go.

We also got to work with the first acrylic tube.  After a bit of research, these are less prohibitively expensive than expected.

PSA: acrylic is brittle. We knew this. And have now confirmed it. Acrylic is brittle. If you were thinking you could drill a 1″ hole in the side of such a tube using an old, rusty, dull spade bit, you would be wrong.

Next steps:

  • Refactor to ½” drain lines
  • Design tube sidewall fitting.
  • Run feed line through side of bucket.
  • Buy 12V DC pump to try.  Trying this one.

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