Safety switch

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Safety switch

Postby RippoZero » Tue Feb 21, 2017 11:47 am

Had an (almost) accident once and thought the possibility of actually blowing myself up doing this was worth some pondering. I've red articles and posts on this site about what can happen and talked to someone who actually had an explosion (albeit on a gas driven still).

The theoretical scenario I've had described to me goes somewhat along these lines: Old man Jon eventually goes down to the cellar to check how his spirits are fearing. Since It's the second run of this batch and the boiler contains a 30% solution of mostly spirits and water the resulting gas is odorless. the still did not have enough cooling and is now effectively a bomb. Once the old man realizes this he either lugs out the contact from the socket or flips the switch on the still. A spark is generated and the still explodes. Even if he had realized it before it might have gone off from the spark of the light switch.

The conclusion is that it's simply to dangerous to do this without proper safety measures. I've therefore decided to build a safety switch for my still. It will be based on the arduino. I just wanted some input on this before i went ahead and put it together.

I'll be using the arduino mini. I've ordered a gass sensor on the cheap from here: http://www.ebay.com/itm/MQ-3-Alcohol-Et ... SwI3RW9Bmq

The switch that will connect and disconnect mains voltage to the still needs to not generate a spark or weld so i went with this solid state switch: http://www.ebay.com/itm/SSR-40DA-40A-25 ... SwPCVX~JED

The plan is to have the mains voltage cut when a certain reading is detected from the gas scensor.
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Re: Safety switch

Postby Pikey » Tue Feb 21, 2017 11:58 am

One of the rules we have is "Never leave a still unattended"

However I'm sure we all pop out for a carp or to brew a cuppa sometimes, so perhaps there's a place for it. The downside as I see it though is that it could lead to complacency and a desire too "automate" the art. I'm also wondering how you'd test it ?
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Re: Safety switch

Postby RippoZero » Tue Feb 21, 2017 12:10 pm

Well i'll be reviewing the possible readings of the ethanol sensor before setting the cutoff point. I thought i'd do this with a small amount of spirits and something to heat it. I'll be testing the sensor on all concentrations of vapor here.

The rest of it will have to be tested on different levels of output from the main element to make sure the switch is reliable. i recon the biggest possible cause of failure in this project might be my code so i will need to test it in a few plausible scenarios.
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Re: Safety switch

Postby NZChris » Tue Feb 21, 2017 2:58 pm

In the scenario you describe, the still would not have exploded as it would not have contained any oxygen for combustion. The explosion would be in the room.
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Re: Safety switch

Postby NZChris » Tue Feb 21, 2017 3:03 pm

A temperature switch reading the condensate temperature can be used to set off an alarm and/or trip a latched relay, cutting the power or closing a gas solenoid valve.
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Re: Safety switch

Postby RippoZero » Tue Feb 21, 2017 3:35 pm

NZChris wrote:In the scenario you describe, the still would not have exploded as it would not have contained any oxygen for combustion. The explosion would be in the room.


Guess that's true

NZChris wrote:A temperature switch reading the condensate temperature can be used to set off an alarm and/or trip a latched relay, cutting the power or closing a gas solenoid valve.


Essentially does the same thing as the ethanol sensor except the sensor will be able to detect leaks elsewhere on the still. I'm not sure if i want to put a valve on the output of my still for three reasons: Don't know what they're made of, More complicated and cumbersome than having a modular ethanol sensor and I don't think sealing the still is a good idea.

The current design plan is to make a box that i plug in to mains of which i can then plug the still to. I'll have a lamp neck to position the sensor in close proximity to the output.
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Re: Safety switch

Postby NZChris » Tue Feb 21, 2017 5:16 pm

RippoZero wrote:I'm not sure if i want to put a valve on the output of my still for three reasons....


That was not what was being suggested. It meant a solenoid valve in the gas line to a propane burner.
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Re: Safety switch

Postby NZChris » Tue Feb 21, 2017 5:30 pm

RippoZero wrote:The current design plan is to make a box that i plug in to mains of which i can then plug the still to. I'll have a lamp neck to position the sensor in close proximity to the output.

A latched relay in the box allows you to daisy chain as many checks as you want into the circuit, Ethanol vapor, condensate temperature, boiler pressure, boiler temperature, boiler level, dead man switch, receiver overflow, timers, whatever takes your fancy.
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Re: Safety switch

Postby Truckinbutch » Tue Feb 21, 2017 5:47 pm

Pikey wrote:One of the rules we have is "Never leave a still unattended"

However I'm sure we all pop out for a carp or to brew a cuppa sometimes, so perhaps there's a place for it. The downside as I see it though is that it could lead to complacency and a desire too "automate" the art. I'm also wondering how you'd test it ?

'Never Leave A Still Unattended' is a mantra that can never be repeated enough . As folks that have been to my place can attest ; I am never beyond 3 steps from my still when it's running . Doesn't take that long to shut down if you have to leave . If you walk away from one running , what guarantee do you have that you will return ? NONE !
I also have an established communication protocol with SOH . If I should ever fail a checkin she will be straight to the still house fully trained on how to shut it down and then deal with whatever issues I might be having .
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Re: Safety switch

Postby Lyonsie » Tue Feb 21, 2017 11:25 pm

I agree its needless. Watch your still. Problem solved.
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Re: Safety switch

Postby RippoZero » Mon Feb 27, 2017 8:39 am

NZChris wrote:
RippoZero wrote:I'm not sure if i want to put a valve on the output of my still for three reasons....


That was not what was being suggested. It meant a solenoid valve in the gas line to a propane burner.

If i was using gas that would be the way to do it

NZChris wrote:
RippoZero wrote:The current design plan is to make a box that i plug in to mains of which i can then plug the still to. I'll have a lamp neck to position the sensor in close proximity to the output.

A latched relay in the box allows you to daisy chain as many checks as you want into the circuit, Ethanol vapor, condensate temperature, boiler pressure, boiler temperature, boiler level, dead man switch, receiver overflow, timers, whatever takes your fancy.

I can make the solid state relay latched using the arduino. my thinking is that once the threshold for cutting the power is met it stays out until i manually press a button to re-open the relay. besides i think it's safer to use the solid state relay since it only let's through current if the arduino energizes it. That way if the arduino for some reason dies, the relay shuts.
Last edited by RippoZero on Mon Feb 27, 2017 9:12 am, edited 1 time in total.
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Re: Safety switch

Postby RippoZero » Mon Feb 27, 2017 9:10 am

Truckinbutch wrote:
Pikey wrote:One of the rules we have is "Never leave a still unattended"

However I'm sure we all pop out for a carp or to brew a cuppa sometimes, so perhaps there's a place for it. The downside as I see it though is that it could lead to complacency and a desire too "automate" the art. I'm also wondering how you'd test it ?

'Never Leave A Still Unattended' is a mantra that can never be repeated enough . As folks that have been to my place can attest ; I am never beyond 3 steps from my still when it's running . Doesn't take that long to shut down if you have to leave . If you walk away from one running , what guarantee do you have that you will return ? NONE !
I also have an established communication protocol with SOH . If I should ever fail a checkin she will be straight to the still house fully trained on how to shut it down and then deal with whatever issues I might be having .

I fail to see how automating the art is a downside. I myself often pop off to get a coffee or something new to read while the still is running. I just think it's a bit naive to assume that we are 100% fail proof cause we're not.
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Re: Safety switch

Postby NZChris » Mon Feb 27, 2017 1:41 pm

Bashing automation and stomping on pot still thermometers are just HD cult mantras. Ignor them.
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Re: Safety switch

Postby Cleco » Tue Feb 28, 2017 9:13 pm

RippoZero wrote:Had an (almost) accident once and thought the possibility of actually blowing myself up doing this was worth some pondering. I've red articles and posts on this site about what can happen and talked to someone who actually had an explosion (albeit on a gas driven still).

The theoretical scenario I've had described to me goes somewhat along these lines: Old man Jon eventually goes down to the cellar to check how his spirits are fearing. Since It's the second run of this batch and the boiler contains a 30% solution of mostly spirits and water the resulting gas is odorless. the still did not have enough cooling and is now effectively a bomb. Once the old man realizes this he either lugs out the contact from the socket or flips the switch on the still. A spark is generated and the still explodes. Even if he had realized it before it might have gone off from the spark of the light switch.

The conclusion is that it's simply to dangerous to do this without proper safety measures. I've therefore decided to build a safety switch for my still. It will be based on the arduino. I just wanted some input on this before i went ahead and put it together.


I'll be using the arduino mini. I've ordered a gass sensor on the cheap from here: http://www.ebay.com/itm/MQ-3-Alcohol-Et ... SwI3RW9Bmq

The switch that will connect and disconnect mains voltage to the still needs to not generate a spark or weld so i went with this solid state switch: http://www.ebay.com/itm/SSR-40DA-40A-25 ... SwPCVX~JED

The plan is to have the mains voltage cut when a certain reading is detected from the gas scensor.



Two things I see. Left unattended and in a cellar which chances are/were, stale air without a draft.
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Re: Safety switch

Postby RippoZero » Thu Mar 02, 2017 6:39 am

Thank you for the feedback everyone. It's much appreciated :thumbup: . I've started building the thing with the parts i have at hand for the moment. Found a fan controller in the barn with a suitable case. What you see on the table there is the power supply for the still and the arduino.
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Re: Safety switch

Postby RippoZero » Thu Apr 20, 2017 2:23 pm

The government is watching us.jpg
Fee-fi-fo-fum, my machine is done. Works quite nicely. The sensor is very sensetive and can be sett to go off at almost nothing. It's not made for high accuracy measurements however. if you blow on the sensor it get's cooler and it's internal resistance changes along with the readings. in adition to this it has to heat up for 15 minutes before it gives consistent readings. for my use, however it works very well. Just having a bottle of strong liquor next to it will tip the safety switch and cut the power. I can only turn the power on again with the reset button when the alcohol level in the air has returned to a normal value.


The black knob adjust the power supply to the still. Thinking about adding a display and some kind of power measuring circuit so that the arduino can calculate how many watt the still is using. For now i will just have to measure voltage and current and find out at what possition the knob is in when 500, 1000 and 2000 watt is delivered.

Bellow is the code for the device. If anyone wants me to comment or explain anything, just ask. I can also give you the source of the parts i used if anyone is interested.

Code: Select all
void setup(){
}

void loop(){
safetySwitch();
}

void safetySwitch(){
    const byte resetButton = 8;
    const byte relayPin = 13;
    pinMode(resetButton, INPUT);
    pinMode(relayPin, OUTPUT);
    byte buttonState = digitalRead(resetButton);
    byte relayState;
    int ethanolSensor = analogRead(A0);

    if(ethanolSensor > 45){
      relayState = LOW;
      digitalWrite(relayPin, LOW);
    }
    if(buttonState == HIGH){
      relayState = HIGH;
      digitalWrite(relayPin, HIGH);
    }
     Serial.println(ethanolSensor);
  }
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Re: Safety switch

Postby Truckinbutch » Thu Apr 20, 2017 5:22 pm

You will never find that shit in my still house . Case to point :
Severe thunderstorm blew over my house today and caused a power outage too brief to kick in my generator . It did , however , require rebooting and reprogramming all electronics that we had in play at the time .
All my stillin equipment is hands on and will remain so .
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Re: Safety switch

Postby Swedish Pride » Fri Apr 21, 2017 12:41 am

nice work lad, could not even start to try to wrap my head around it but looks cool and sounds like it works well :thumbup:
I've a more basic set up for lack of knowledge and funds, not because I'm an old codger like TB :sarcasm: :think:
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Re: Safety switch

Postby Still Life » Fri Apr 21, 2017 12:51 am

Old electronics builder here. If I had an Arduino in my day I'd rule the world. They can be programmed to do anything.
Nice code work and nice build. Nowadays I admire electronics from afar, standing next to a still.
You've got the best of both worlds right there.

Don't worry about the naysayers. I still have close friends who are POSITIVE my still is a boiler bomb waiting to explode.
It's all in what you know and how you use it.
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Re: Safety switch

Postby NZChris » Fri Apr 21, 2017 1:25 am

Truckinbutch wrote:You will never find that shit in my still house . Case to point :
Severe thunderstorm blew over my house today and caused a power outage too brief to kick in my generator . It did , however , require rebooting and reprogramming all electronics that we had in play at the time .
All my stillin equipment is hands on and will remain so .

The little automation I have restarts with no problems. I ran for decades with no automation, but now the price of controllers to make a distiller's life easier is so cheap it's hard to ignore. The controller looking after the Leibig of my Charantaise setup saves so much water and hassle I should have done it years ago, and would have if I had been paying for the water.
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Re: Safety switch

Postby Kegg_jam » Fri Apr 21, 2017 1:54 am

Question on the code.

I thought you were supposed to define constants and pin assignments in the Setup() routine....

Seems to me you are redefining your constants every time through the loop() instead of just once in Setup().
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Re: Safety switch

Postby RippoZero » Fri Apr 21, 2017 2:13 am

Truckinbutch wrote:You will never find that shit in my still house . Case to point :
Severe thunderstorm blew over my house today and caused a power outage too brief to kick in my generator . It did , however , require rebooting and reprogramming all electronics that we had in play at the time .
All my stillin equipment is hands on and will remain so .

I've accounted for that by making the switch default to OFF upon a startup. if the power were to fail the arduino would restart and open the supply of power only if i push the big black button.

Swedish Pride wrote:nice work lad, could not even start to try to wrap my head around it but looks cool and sounds like it works well :thumbup:
I've a more basic set up for lack of knowledge and funds, not because I'm an old codger like TB :sarcasm: :think:

It's not as hard as it looks. I recon you would be able to put one of theese together nicely with propper documentation from my side. the biggest challenge when someone has done something like this before you is getting the wiring right. the code is just copy paste.

Still Life wrote:Old electronics builder here. If I had an Arduino in my day I'd rule the world. They can be programmed to do anything.
Nice code work and nice build. Nowadays I admire electronics from afar, standing next to a still.
You've got the best of both worlds right there.

Don't worry about the naysayers. I still have close friends who are POSITIVE my still is a boiler bomb waiting to explode.
It's all in what you know and how you use it.

I don't worry to much about the nay sayers but i do take their points into consideration. Having a still be run by shady and twisty hobby electronics is defenetly a bad idea for most people. That is part of the reason why i've started out by making safety features.

NZChris wrote:
Truckinbutch wrote:You will never find that shit in my still house . Case to point :
Severe thunderstorm blew over my house today and caused a power outage too brief to kick in my generator . It did , however , require rebooting and reprogramming all electronics that we had in play at the time .
All my stillin equipment is hands on and will remain so .

The little automation I have restarts with no problems. I ran for decades with no automation, but now the price of controllers to make a distiller's life easier is so cheap it's hard to ignore. The controller looking after the Leibig of my Charantaise setup saves so much water and hassle I should have done it years ago, and would have if I had been paying for the water.


I agree. Thinking i might automate the wash process a bit for my next build. still something i need to read/check up on thought. No reason to reinvent the wheel every time.
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Re: Safety switch

Postby Pikey » Fri Apr 21, 2017 2:20 am

Nice one - could you use the same kit to switch off if your boiler went over pressure ? or would you need to build another ?

Chris - does your water controller just switch on / off ot does it do variable flow adjustment ?
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Re: Safety switch

Postby RippoZero » Fri Apr 21, 2017 2:28 am

Kegg_jam wrote:Question on the code.

I thought you were supposed to define constants and pin assignments in the Setup() routine....

Seems to me you are redefining your constants every time through the loop() instead of just once in Setup().


I think i read something somewhere that it did not matter where you defined your constants in c#. i might be wrong though. I've started doing it this way to keep track of them in bigger sketches. when you start having four and five of these methods in one sketch the amount of backtracking to find out where everything goes gets ludacris. The best allternative might be to declare them as global variables and put them above the block of code they reppresents like this:
Code: Select all
void setup{
}

void loop(){
safetySwitch();
}


    const byte resetButton = 8;
    const byte relayPin = 13;
    pinMode(resetButton, INPUT);
    pinMode(relayPin, OUTPUT);
    byte buttonState = digitalRead(resetButton);
    byte relayState;

void safetySwitch(){
    int ethanolSensor = analogRead(A0);

    if(ethanolSensor > 45){
      relayState = LOW;
      digitalWrite(relayPin, LOW);
    }
    if(buttonState == HIGH){
      relayState = HIGH;
      digitalWrite(relayPin, HIGH);
    }
     Serial.println(ethanolSensor);
  }
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Re: Safety switch

Postby NZChris » Fri Apr 21, 2017 3:01 am

Pikey wrote:Chris - does your water controller just switch on / off ot does it do variable flow adjustment ?

On/off, but with a reservoir which acts to smooth the on/off effect.
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Re: Safety switch

Postby RippoZero » Fri Apr 21, 2017 3:33 am

Pikey wrote:Nice one - could you use the same kit to switch off if your boiler went over pressure ? or would you need to build another ?

That could be done but it would require me to install a preassure sensor somewhere on the still and run some detachable wire between the arduino and the sensor.
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Re: Safety switch

Postby Yummyrum » Fri Apr 21, 2017 3:17 pm

Rippo
Nice one mate and any protection is good .
I like your thinking on using a SSR to switch the power to avoid potential sparks :thumbup:

But .... having been an electronics tech for over 30 years and replaced thousands of semiconductors , transistors , SCRs and Triacs that have gone short curcuit I would not place my life on one .
Do you have a way to check that the SSR is functioning everytime you use this ?

Or even operate a remote contactor on the switch board .
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Re: Safety switch

Postby HDNB » Fri Apr 21, 2017 5:02 pm

I have considered doing a multi-point safety shutdown, not so i can leave but rather so it can shutdown automatically before i have a chance to lift my ass off the chair.

3 weeks ago about 4 hours into a run everything was stabilized i was in the middle of hearts and nothing had varied for hours.
thought i'd make a double check of everything and sneak out for quick minute and be right back...walked over to the still from about 10' away, glancing down at the steam valve, which was right was where it was supposed to be and when i looked up the output started blowing vapour -hard... :wtf:

slapped the "near" holyfuckswitch (there are 3 wired in series about the shop) and watched the still evacuate vapour for about 2 minutes as the jacket cooled.

went about my business and when i got back in a couple minutes i fired it up again and completed the run without incident without varying anything on the system. I have no idea what caused the vapour spewing. Looked and looked but nothing was askew. Can only guess it was a vapour lock in the deflag or PC that caused cooling water interruption.

so maybe an alcohol detector would have shut it down or maybe the air current would have dragged the vapour in the direction of the fire instead of the detector. who knows.

some glad i was there to shut it down and it certainly reinforced why i never left before...and ain't gonna leave in the future.
I finally quit drinking for good.

now i drink for evil.
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Re: Safety switch

Postby RippoZero » Sat Apr 22, 2017 3:09 am

Yummyrum wrote:Rippo
Nice one mate and any protection is good .
I like your thinking on using a SSR to switch the power to avoid potential sparks :thumbup:

But .... having been an electronics tech for over 30 years and replaced thousands of semiconductors , transistors , SCRs and Triacs that have gone short curcuit I would not place my life on one .
Do you have a way to check that the SSR is functioning everytime you use this ?

Or even operate a remote contactor on the switch board .

You're right. Having the solid state relay short circuit does represent a potential fault. I do have a fuse in the thing that goes at 250 volts and 10 amperes or 2500 watt. This is well below the rated maximum for the relay. Is this a good solution? I do get to personally check if the relay can open and shut properly every time I start the device. while the sensor is heating up for about 15 minutes the only way to open the relay is to hold in the button. if I let it go in that period the sensor will detect a false positive and shut the relay. I think the part in this system that represents the biggest potential of failure is the MQ-3 gas sensor. Maybe I should double up on that and have 2 of them?
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Re: Safety switch

Postby Yummyrum » Sat Apr 22, 2017 11:45 pm

RippoZero wrote:You're right. Having the solid state relay short circuit does represent a potential fault. I do have a fuse in the thing that goes at 250 volts and 10 amperes or 2500 watt. This is well below the rated maximum for the relay. Is this a good solution? I do get to personally check if the relay can open and shut properly every time I start the device. while the sensor is heating up for about 15 minutes the only way to open the relay is to hold in the button. if I let it go in that period the sensor will detect a false positive and shut the relay. I think the part in this system that represents the biggest potential of failure is the MQ-3 gas sensor. Maybe I should double up on that and have 2 of them?

Having a fuse is always a good idea but semiconductors generally destroy themselves in a fault situation quicker than a fuse blows .

So long as you have a light across the element so you can see when the relay is supplying power ( either when its ment to or not ) and an audiable alarm to indicate the presents detected alcohol so that if you are not in theroom , you can here it and come quickly and double check that power has been cut would be a good thing .
Yes I think maybe a few sensors might be a good idea .Its common practise to have several smoke detectors in a house nower days so why not :thumbup:
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