Update to my diaphragm pump controller

[Biz]

I have been working on a cool new feature for my diaphragm pump controller, aka "Smart Sap Sucker". I have added a vacuum sensor, so that the controller knows what the vacuum level is. The advantage of this, besides allowing display of vacuum on the controller, is that we can better control the point where the pump shuts down, and maximize efficiencies in battery life / sap production.

On the diaphragm pumps such as most Shurflo models, when sap stops flowing, the vacuum is reduced. I often see 10-12" if sap has stopped flowing but the pump hasn't shut off yet, versus 25" or more when the pump is running and sap is flowing strong. So with the new vacuum sense feature, we can now turn off the pump automatically when the vacuum drops rather than when temperature drops. This has three main advantages, one, the pump doesn't shut off is sap is still flowing, so we can maximize sap production; two, if sap stops flowing because trees have stopped producing sap, regardless of temperature, the pump will turn off to conserve battery power. I have often seen this on my relatively short runs of 20-30 taps. This also produces a third benefit, it reduces wear on the diaphragm by minimizing the amount of time that it is running dry.

I have posted a new Youtube video showing a demonstration of this in the test setup in my cellar. Check it out here:

https://www.youtube.com/watch?v=KrI5LVAviQg&t=1s

Any questions, PM me or email me, mountainmaples3 at gmail dot com.

[wmick]

Love this stuff - Good job..
I put together a little 12v diaphragm system last year, at the last minute and didn't have much time to play around or experiment..
Curious about some of the logic you've used..
How long of duration in "low vacuum" till shut-down happens? or is it adjustable?
and "startup" in the morning... what happens if vacuum doesn't come up quickly in the morning when it starts up? Does it shut down and try again later?

[Biz]

Great questions, I have thought about those. Right now once vacuum has risen above a "high vacuum" limit like 20", the unit will shut down as soon as vacuum goes below a "low vacuum" limit, like 14". No delay but could add one if needed.

At startup there is a delay to wait for vacuum to rise above a "vacuum fault" limit. I use something low like 7" for this one, and delay for 1 minute (adjustable). It is intended to shut down if there is a vacuum leak. In my systems with 3/16" tubing the vacuum comes up quickly to about 10-12" in just a few seconds then it won't go higher until sap starts flowing.

Dave