High temp shut down switch

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High temp shut down switch

Postby Danbo » Wed Aug 05, 2020 8:56 am

Has anyone installed a high temp shut down on their still? I was thinking of this the other evening. What if you fell asleep waiting for the run to complete...I feel this may be a good safety feature. I'm sure it has happened.
I have a pid I'm using as a thermometer and a spare ssr that may work to put something together. I do follow all rules in my day job as well as off work activities, so it's not for lack of trying, just a precaution.
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Re: High temp shut down switch

Postby Sam. » Wed Aug 05, 2020 9:10 am

The text book answer would of course always be don't run the still tired or intoxicated :-B

However anything to make the process safer in case something happens out of your control, heart attack, meteor strike or herd of wild buffalo etc then why not?
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Re: High temp shut down switch

Postby chipboy » Wed Aug 05, 2020 2:14 pm

Quite easy to implement, what temperature would you consider too high?
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Re: High temp shut down switch

Postby bluc » Wed Aug 05, 2020 5:02 pm

Where would you put sensor? in boiler? :think:
I think pressure sensor or relief valve in boiler and a ethanol vapor sensor, at spout or at base of colum may be useful also..
Last edited by bluc on Wed Aug 05, 2020 5:04 pm, edited 1 time in total.
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Re: High temp shut down switch

Postby chipboy » Wed Aug 05, 2020 5:12 pm

Bit of a loaded question actually, given the elements are covered its not going much above 100 degrees until they are revealed and then you have no temp as they are in free space not limited by the latent heat of evaporation, the energy to get water to steam.

So somewhere between azeotropic and 100 is the answer, depending on elevation.

More than prepared to assist.
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Re: High temp shut down switch

Postby The Stig » Wed Aug 05, 2020 6:34 pm

The way I read this question it’s bordering on automation.
I think Danbo is talking about putting a temp prob at the top to measure temp of the vapor past say 81 then shut down the still.
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Re: High temp shut down switch

Postby chipboy » Thu Aug 06, 2020 7:23 am

Simple automation, safety shutoff.

Put one in the liquid at a height that protects the elements, once it reaches the set point, turn off. Put a second if you must in the vapour but this is going to be a bit less reliable and lower temperature than the liquid. The heat source is presumably in the liquid.
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Re: High temp shut down switch

Postby Sam. » Thu Aug 06, 2020 8:58 am

chipboy wrote:Simple automation, safety shutoff.

Put one in the liquid at a height that protects the elements, once it reaches the set point, turn off. Put a second if you must in the vapour but this is going to be a bit less reliable and lower temperature than the liquid. The heat source is presumably in the liquid.


Nah, the probe in the liquid will take forever to shut off, you would want it in the vapour path, or even better the output temp would be better, if shit goes pear shaped hot liquid is a very quick indicator, a friend told me... :))
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Re: High temp shut down switch

Postby chipboy » Thu Aug 06, 2020 1:58 pm

Sam, not wanting to meet either hot liquid or vapour, both are particularly nasty!

Why would you prefer the vapour and why is it quicker, it will never be above liquid temp, laws of thermodynamics etc?
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Re: High temp shut down switch

Postby warramungas » Fri Aug 07, 2020 9:45 am

Most smaller kettle styrl boilers have an over temp or boil dry trip. Not surehow they workbut presume like a normal ketle with a metal strip of some sort.
Could you set something up to work on resistance for the element/s? Hot element = less resistance?

Not sure how the commercial boys do it but they must have some sort of overload switches. Maybe.
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Re: High temp shut down switch

Postby Sam. » Fri Aug 07, 2020 1:08 pm

chipboy wrote:Sam, not wanting to meet either hot liquid or vapour, both are particularly nasty!

Why would you prefer the vapour and why is it quicker, it will never be above liquid temp, laws of thermodynamics etc?


Probably actually best for output liquid temp, if shit goes wrong that will get hot quick
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Re: High temp shut down switch

Postby chipboy » Fri Aug 07, 2020 4:41 pm

Agree Sam and its a stable temp source, so the only decision is the set point. I recommend 90-95 as this is prior to boiling where water coverts to steam expanding 1000 times its volume, this is where things get really bad=, things go to shit in a seriously bad way.
Last edited by chipboy on Fri Aug 07, 2020 4:42 pm, edited 1 time in total.
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Re: High temp shut down switch

Postby chipboy » Fri Aug 07, 2020 5:05 pm

I forgot to add if you need design assistance or help with this just ask, its easy. Might do one for myself first, another hole in the keg groomet or gland to seal it. Dallas 18B20 sealed or more expensive RTD / Thermcouple, plus controller and solid state relay. Just like my chest fridge holding the beer and home brew ginger beer.

It should be located to be a safety for the elements so think about that too.
Last edited by chipboy on Fri Aug 07, 2020 5:08 pm, edited 2 times in total.
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Re: High temp shut down switch

Postby bluc » Fri Aug 07, 2020 5:19 pm

Am I wrong or is pressure release more important :think: without there is explosion, with a fire..
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Re: High temp shut down switch

Postby Sam. » Fri Aug 07, 2020 5:20 pm

chipboy wrote:Agree Sam and its a stable temp source, so the only decision is the set point. I recommend 90-95 as this is prior to boiling where water coverts to steam expanding 1000 times its volume, this is where things get really bad=, things go to shit in a seriously bad way.


For the output temp I would have it way lower like 40c
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Re: High temp shut down switch

Postby chipboy » Fri Aug 07, 2020 9:32 pm

Sorry below distillation temp? I would have thought a point at which take off stops and flavours of tails are no longer wanted / required, what might his be?
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Re: High temp shut down switch

Postby Sam. » Fri Aug 07, 2020 10:09 pm

chipboy wrote:Sorry below distillation temp? I would have thought a point at which take off stops and flavours of tails are no longer wanted / required, what might his be?


Nah I meant to cut it off if the output liquid temp rises to 40 degrees c which would either mean your cooling water is shut off or it's running that hard that something has gone wrong, depending on your climate will depend on output temp
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Re: High temp shut down switch

Postby chipboy » Sat Aug 08, 2020 7:24 am

Ah ok differential 40 above coolant that makes sense, just need to fit a sensor to the pipework. This together fitted with mash temp sensor to protect elements is quite simple.
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Re: High temp shut down switch

Postby Sam. » Sat Aug 08, 2020 10:19 am

Although you may be wanting to do this for a safety feature I do share Stigs concern that if you have a system such as this is can breed complacency and lead to relying on it instead of it being used for it''s intended purpose.

If you did build one I would suggest testing it under different operating conditions to make sure it is in fact going to work.
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Re: High temp shut down switch

Postby gad » Sat Aug 08, 2020 11:27 am

Danbo wrote:What if you fell asleep waiting for the run to complete....


If that's what your worried about a much simpler / cheaper / safer solution, like a mechanical timer with alarm should do. Something like this:
https://www.kitchenware.com.au/avanti-mechanical-timer.html?gclid=EAIaIQobChMIiOyxoriK6wIVVaWWCh09cAfPEAQYBCABEgJaG_D_BwE

Though, I can't imagine I'd ever be running my still if there was even the slightest chance of me falling asleep while it was running !
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