Wow......ah'm impressed (why didn't I think of that!!!). My own is a much larger anti-siphon/negative pressure valve incorporating a ping pong ball with much tubing leading in. This is used when the holding tanks are full and the supply lines have to be shut off. I use negative pressure in the tanks and pressure sensors to warn me if the tanks re-pressurize (a constant early morning worry). This gizmo will also allow the drawing of sap from lower elevations which has been problematic.

As one who is about to quadruple scale his syrup production this device is certainly on my to-get list.

Thanks Milo (Menzies does have a way of putting the numbers crunch on visualization)

Every innovation, design, or technological advancement began with a thought, a notion or "let's see what happens when I do this" and the belief, optimism or dream that transforms it to reality.

"let's see what happens when I do this"

This is often followed by "no-one thought that would happen".

No one thought these would happen

http://science.howstuffworks.com/9-things-invented-or-discovered-by-accident2.htm