"Stillsmart" custom controller

[Iain]

Hi all now I have your attention ..

I have to move shortly so not going to have my still(s) running .. so I was thinking about a project i could be getting on with that I have been thinking about for a while !

I enjoy electronics as a hobby .. so I was thinking about a power controller to vary the power input into a still ..then I thought what about a feedback system so it could read temperatures and adjust accordingly ..

Now I don't really want a fully automated still (where's the fun in that!) but something to just make life easier ... looking at custom programming a PIC chip as the "brains" of the operation ..

So any ideas / thoughts here would be good that I could incorporate ..

Just to make my aim clear I am not after this just for myself or to make money .. the plan is if it all works nicely I will release the code (or program pics for people) on this site so everyone can benefit .. I intend to make the circuit as simple as possible so everyone can benefit - which I think this site is really about

Good idea or a failure waiting to happen ? well lets all chip in and see what we can do !

Iain

[YHB]

Iain,

Maybe I have misread your post in which case I apologise and if I have then please point me in the right direction, but ...............

When a still boils the temperature of the wash and vapour is determined by the ABV of the wash and not by the amount of power applied.

As the Alcohol is drawn off, the ABV goes down and the temperature goes up. Turning the Power up will not make the temperature rise it will just make the wash boil more vigorously. Turning the power down will just stop the wash from boiling. Or am I missing something?

[chill]

No, you are correct. Varying the power simply varies the rate at which steam is produced. The boiling temperature does not change based on input power, it changes based on the composition of what is left in the boiler. You could use one to put a lot of power in for the initial heat up and then reduce for the actual run.

Chuck

[Iain]

Indeed - however what I was looking at was a feedback loop so the power controller could read the temperature of the vapour and react accordingly ...

Was trying to get my initial thoughts down when I posted and missed that bit out ..doh !!!

[Myles]

Not sure what you are trying to do - pot or reflux column.

On a pot still controllers are good for consistency between runs. Once you have found a power level for a specific recipe so that it drives off the heads correctly and gives you a decent hearts cut - then you want to be able to replicate that the next time.

Vapour temperature control suggests that you are thinking about the top of a column - and wish to maintain stability throughout the run. Now most folks don't do this by controlling the boiler input.

The typical control system on a reflux column is to set the power to give yourself a specific vapour speed / volume of vapour, in the column. Yes there is power control involved for stabilisation at low power then switch to hearts phase power level. However, in general you don't adjust the power during the run.

It is more typical to control the vapour temperature by adjusting the reflux ratio.

Temperature control of the coolant in the dephlegmator or reflux coil is something worth looking at though.

Can you expand on which situation you are considering?

[John51]

Automated coolant temperature control would put CM stills up there with the best imo.

[Myles]

Automated coolant temperature control would put CM stills up there with the best imo.

Absolutely agree with that. CM stills went a bit out of favour (for producing neutral specifically) because some of the other systems were a bit more user friendly. A VM for example practically runs itself once it is set up.

However for a flavoured or even for a "slightly flavoured" product a CM is a good tool. Add in coolant temperature control and you move into a different league entirely.

I am a big believer in using different tools for different jobs.

[Iain]

Right full background is that I have just purchased (very cheaply) a still spirits super reflux still .. after reading on here and raiding my electronics parts bin I have managed to get a fairly consistent 91% abv .. which by all accounts isn't the best but certainly isn't too shoddy (only done two runs upto today .. and some plonker from a utility company just severed my mains water so tonight is out !)

having bodged a power controller together (as in rough and ready not as in dangerous) it got me thinking about the following potential setup :-

Stage 1

Microcontroller running pwm so controlling the heat put into the boiler with a temp feedback on the ss still ..ie automated flat out upto 50 .. alarm ..switch water on .. run it up to higher temp and stabilise , etc ..

Stage 2

Monitor the coolant temp on the condenser coil as well as the knock down coil.

Stage 3

Replace the alarms with electronically controlled valves so the power controller can also control the water flow based on coolant flow for both cooling sides.

Hopefully that makes a little more sense ?

Iain

[Anavrin]

Hi Iain

I see its been a while scince you first posted about this but I've just come across it and I'm wondering if you got any further with your idea?
I have been having a similar thoughts myself, I am an electrical/electronic engineer by trade and as a result I'm constantly thinking how can I improve the control of my still by reducing the possibility of human error and acounting for unforseen variables before its too late, such as a change in water temp or flowrate that you wouldnt notice until something started changing during your run.

I wasnt thinking PIC controlled, I like to keep things as simple as possible so I have been thinking about some simple comparitor monitoring the water temp leaving a coil within the columb, like the coil in the T500 columb

This could be compaired wit the temp of the vapor at the take off point or even the temp on the main top condenser in my Boka.

My theory (that I'm making up as I type this) is to control all the reflux within the main colum by varing the cooling flow in the columb its self so that the only vapour passing up through my slant plates is alcohol vapour (or as close to it as I can get)

The electronics, once fine tuned would give an early indication as to the effectiveness of the cooling flow and indicate when to increase/decrease the cooling flow.

Once the relationship between water temp leaving the columb and vapour temp has been established it could be automated with a flow control valve but I've got a feeling if such valve excists it would be prohibitably expensive.

I'll have a think about this, I'm thinking out loud more than anything