Reflux Column Control Maybe???

rkidtech · Post by **rkidtech** » Wed Jun 22, 2005 1:52 am

Hello everyone,
I have a question about possible regulation of the reflux column temperatures on my valved reflux column. I have the usual glass thermometer for my still. But I also have a digital thermometer that reads out to 2 places after the decimal point, it also walks, talks, sings and has all the usual bells, flutes and whistles on it.
Here’s my point/question:-
Is there any safe, practical cheap way that you can link up this small 2.4 volt battery operated digital thermometer to the mains electric 240 volt heating element? My reason for wanting to do this is to give me greater control over the reflux in the reflux column. (I’m just reading over my email and have just realized I have control via the reflux needle valve) But let me continue for all those internal reflux column stills. Hopefully this will get the electric element to kick in at78.5 Degrees C the boiling point of ethanol alcohol. Thus giving good reflux control within the column
Now I know the electric element, although hot and nearly at the correct temperature, it will take a margin of time to get up to the exact temperature. So although not deadly accurate as to holding the exact boiling point, with a bigger element this gap/margin of error could be closed to as near as makes no difference to us anyway.
Or the other way of using an electrically operated water valve to control the cooling water to the column.
Let’s suppose this could be done relatively cheaply. Would this not be a better way to use technology to our advantage?

Geoff.
P.S.
As a spin off of this accuracy(if it could be done) if you saved all the heads from different runs and if you knew all the different temps (I don’t) to get the different alcohols out at, you could in theory separate out digitally, what little methanol is in there, and whatever else there is etc.
The only fly in the ointment I think, would be the reflux column heat controllability, because when you are working with different alcohols having boiling temperature differences being only1 or 2 tenths of a degree apart your column heat control would have to be spot on.
But thinking of it another way, why go to all that trouble to make furniture polish or lacquer when all you want is greater reflux heat control in the column and better alcohol purity.
What do you guys think or has this subject already been covered?
Geoff

Rocky_Creek · Post by **Rocky_Creek** » Wed Jun 22, 2005 2:54 am

You don't want to do that.

Brett · Post by **Brett** » Wed Jun 22, 2005 3:46 am

i made a post about the same idea in the research n theory part of this forum read through that n u will see the answers you want.

Yttrium · Post by **Yttrium** » Wed Jun 22, 2005 5:45 am

How much control you want over the heating element will determine how complicated of a project it will be to control it by a digital thermometer. It probably wouldn't be that difficult to toggle the heating element on or off based on the read out of the thermometer. If you want more than crude on/off switch, well then things are going to get tricky.

Do you have a link to the type of thermometer you have?

By the way, even though the thermometer reads out to two decimal places doesn't mean its accurate to two decimal places.

Rocky_Creek · Post by **Rocky_Creek** » Wed Jun 22, 2005 5:51 am

What you want is the power matched to the column. The tempertature will take care of itself.

rkidtech · Post by **rkidtech** » Wed Jun 22, 2005 7:39 am

Hello again guys,
I shall do a bit of back reading here Brett. It’s well seen I’m new to the hobby, and here’s me thinking I was being all original like. Sometimes the most obvious thing to do isn’t always the best thing to do even to the most experienced person. How often have you heard an old timer in a job say it’s been done like that for over a 20 years now. I’ll stick to the old way. But experience can sometimes blind you.
In my plumbing career I’ve been caught out like this all too often by a young whipper snapper and a new idea that was right in front of me and I just didn’t, and couldn’t see it because of my experience and this dated idea that it’s been done like this for years, and must be right idea, has got in the way.
Don’t get me wrong now fella’s I’m not saying for one minute anyone is wrong and would never presume to do so. It’s a case of: - it’s not often you’re right Geoff but you’re wrong again (but I’ll learn). Unless I have tried it and failed myself. I suppose I’m naively playing devil’s advocate by wrongly stating the obvious
But it also gives you guys the chance for me to learn from your knowledge and experience. Thanks guys I suppose this really is the purpose of the forum
The master plumber I was taught under told me once. That the more you get to know about a subject, the more you realize there’s a lot you don’t know about it, and there’s a lot more back ground stuff you can still learn. Or put another way
The more you know, the more you know, you don’t know. Which at first sounds stupid, but it isn’t when you stop and really think about it
Which is precisely like me with this hobby. So keep the good stuff rollin’ lads
Geoff

rkidtech · Post by **rkidtech** » Thu Jun 23, 2005 1:36 am

Hi Uncle Jesse,
You sent me a private message notification link, but when I hit the link all I got was the Home Distillers Forum. Can you supply a different link? Or what?
Geoff

goschmil · Post by **goschmil** » Wed Jul 06, 2005 10:07 pm

You do not want to regulate the heating element with an on/off thermostat switch trying to establish tower equillibrium, you power match the tower like was said earlier or you constantly/consistently regulate the amperage available to the element which could become quite expensive depending on the wattage of the element.
I've constructed a little doo dad comprised of four 600W cheapo $9 incandescent light dimmers wired in parallel mounted in a metal box and can deliver the full 1500W and infinite choices in between. Works great for finding that sought after temp. ; I'm also using a digital that reads right of the decimal, it's really cool to see how a puff of wind can affect the tower temp when you can read into the hundreths. By the way, thermostat control of a current limiting device requires even more complexity.

sot · Post by **sot** » Thu Jul 07, 2005 12:45 am

For a project (not alcohol related) I built a simple temperature controller that had the liquid stable to 0.5'C. All it did was power a relay if the temp was too low and turn it off when too high. Hardest part was getting the thermistor (probe) water tight, it kept getting waterlogged. I ended up snipping the probe off an aquarium digital thermometer and using that instead. It's an old book I got the schematic from and some of the designs claim stability to 1/1000 of a degree Celcius.

No idea if such control is useful for distilling but if you do want to experiment I'd suggest using a mains output regulator (beefed up light dimmer) and adjust it manually to get the temps you want. That way you'll see just how useful the idea is before automating it. If the idea is a goer you'll already have the probe built into the boiler and that can be used with different circuitry to provide feedback to the regulator.