Hi all

[dmachura]

After doing a lot of research I've built myself a 40 x 2 inch reflux still, using pid control works like a charm. I've now made 10 batches of neutral spirits at 175% using bird watches excellent sugar wash recipe. Thanks to bird watcher, odin, and george from Barley and Hops videos.

[Jack C]

Hello demachura and welcome to the forum. Glad you are doing well. I would ask that you do a HD search on using PID for distilling and read up. Not to bash George but there is some ideas that may not be sound on running your still trying to control wash temp. Please don’t take my word for it and read up and really hope you continue to have success and enjoy the hobby.

[dmachura]

As a instrumentation engineer I am quite versed in PID control and would beg to differ with anyone that disagrees, especially if your using a reflux column still. If your using a pot still then the argument for not using PID control may be valid but I'm still experimenting with that.

[OtisT]

Welcome to HD dmachura.

I’m not going to disagree that you know how to control a PiD, but knowing PID control is one thing and knowing how to properly separate the fractions with a column is an entirely different thing all together. No correlation between the two.

To separate fractions in a packed column requires a consistent and steady flow of vapor. If your vapor speed is constantly increasing and decreasing from the on/off cycles of your element, your separation will suffer and you won’t be able to compress various fractions as well as you may want.

You will be better off if you run your PID in a manual mode for an steady supply of power to the element.

Best of luck,
Otis

[dmachura]

I believe you've described exactly why many people have problems with PID control. A properly tuned controller should not cycle after the first 4 cycles, (1/4 amplitude decay). I can control my vapor temperatures exactly, so the PID puts out only the power that is required. Its really not that different from manual. You still have to watch your production but once you get to know the temps for your still the controller does all the tweaking for you.

So for anyone that sees cycling when using a pid controller you must tune the controller.

[BoomTown]

I believe you've described exactly why many people have problems with PID control. A properly tuned controller should not cycle after the first 4 cycles, (1/4 amplitude decay). I can control my vapor temperatures exactly, so the PID puts out only the power that is required. Its really not that different from manual. You still have to watch your production but once you get to know the temps for your still the controller does all the tweaking for you.

So for anyone that sees cycling when using a pid controller you must tune the controller.

Don’t mean to sound dumb, but what is PID?

[Oldvine Zin]

Welcome in!

This is the welcome Center so I hope you post your experiments and findings in another appropriate thread. I'm not a believer in PID"s used for distilling but maybe you can prove me wrong. I use a PID in my espresso machine and it works great for that, but that is not the same as distilling.

Stay safe
OVZ

[Tummydoc]

You are controlling your vapor temp? Not possible. The boiling point and vapor temp are determined by the relative proportion of the constituent alcohols and water. A 30% ethanol in water mixture will boil at a fixed temp based on physics. The vapor temps climb as the relative proportion of ethanol decreases. You can control power and in turn vapor speed, but temperature is not a variable under your control. That is why many of us feel a PID is not the best controller for modulating the heat source and take issue with George (Barley and Hops). Now if you're using the PID to adjust water flow to a dephlagmator (via a solenoid) perhaps the PID has a role here.

[dmachura]

I'm moving this conversation over to research and theory forum..