Raspberry Pi Still Contoller

[TimothyChurch]

I've decided to take things to the next level! After getting a few things squared away professionally, I have a timeline for setting up my DSP here in a couple of years. Until then, it is time to start making sure my practices are more on the professional level and start getting all my systems in place.

One of the things I've always wanted to do it to automate my depleg control. I run a modular bubble plate still with up to 4 plates at the moment. As legally in the US whiskey has to be 160 proof or lower, I've been running 2 plates on my flavored product and dialing in my take off to 80%. I normally go through the song and dance at the end of the run of adding some heat and increasing reflux to push down the late tails a bit. While for repeat runs, this isn't bad they have their 6%ish ABV plus usually, a gallon of feints at 65%, the first one of the batches have so little alcohol they need a bit more pampering!

So in comes the automation!

**DISCLAIMER** Just because I know it will be said because it always is. Just because I am automating something, does not mean I'll be leaving the still unattended. I'm simply taking one variable off my hands so I can fine-tune my product!

Here is the rather rough dashboard at the moment

DistilleryUI.JPG

I have 5 temperature probes: the jacket water, the pot, the vapor at the bottom of the column, the dephleg output, and the head vapor temp.
The control points will be the heating element as well as two valves directing coolant towards or away from the dephleg.

Here are my proposed steps for running it with my system.

Turn on the system and hit preheat. Preheat is going to be set just under the boiling point of some of the lower boiling heads for safety. The jacket and pot are run using a cascade PID system so there is no pressure build-up. (System is rated for 15 PSI and I never go above 5 even when cooking corn)

Turn on the water. The coolant loop will feed from the city water. First will be a large needle valve for overall flow control with a bypass valve just in case. The water will flow into the PC and then from the PC to two valves. The valve going to the depleg will be a default open valve with the bypass being a default closed. While normally people run two loops (that's how I have it now), that is typically to avoid constantly adjusting things. The point of this is to be able to constantly adjust the system and the slightly warmed water from the PC allows me to have a slightly higher flow through the dephleg.

Once the still is preheated, it will be switch to manual mode to begin the run and stack the plates. The needle valve will be adjusted till the dephleg output is just over full reflux. At this point, the dephleg target temp will be raised to draw off heads.

Once heads have been collected, it will be dialed in to the desired ABV based on dephleg temp and allowed to run.

At the end of the run, there will be a tails button to switch off the dephleg and finish the run. Once the charge temp shows it to be below a certain ABV, the system will shut down.

While this is happening, there will be charts showing all the temps as well as the ABVs. I'll set these up to get logged for each batch.


Now this is still in development! I'm working on the system using Node-Red for easier programming (my code is a bit rusty). I'd love to get any thoughts y'all might have or features you think would be nice to see. I'd be happy to share the code once I've flushed out all the bugs!