Cooling flow failsafe?

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Bobbywolf
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Cooling flow failsafe?

Post by Bobbywolf »

Let me preface this by saying I in no way intend to leave my still unattended.

Anyways, I can envision a scenario where my cooling water (coming from a well) stops. I haven't run the well dry yet, but some day it could, and possibly while I am running.

Is there such a device that would sense the drop in cooling water flow, and then trip a circuit? I am always in the garage while running, but not always staring at the thing.

What would this this device be called? I'm sure I'm not the first person to want this functionality on an electric still.

Thanks.
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NZChris
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Re: Cooling flow failsafe?

Post by NZChris »

An STC-1000 & a relay to switch off the power to the elements if the condenser outlet gets over the setpoint should do the trick fairly cheaply. This requires a start button and a circuit to latch the relay on until a fault breaks the circuit.
Maritimer
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Re: Cooling flow failsafe?

Post by Maritimer »

What you are looking for is called a flow switch. Look for consumer-grade flow switches on ebay. You can wire it into the pot circuit of an electric power controller: http://homedistiller.org/forum/viewtopi ... r#p7257521 . I built my own before I knew about the ones on ebay: http://homedistiller.org/forum/viewtopi ... ilit=+poor . I use it every run. Nice thing about it is you can see and hear it working.
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DAD300
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Re: Cooling flow failsafe?

Post by DAD300 »

I've been planning a fail safe cooling circuit.

It's the only way I can envision it in the case of an electrical, municipal/well or pump failure.

Before starting still, pump enough water for a run to a tank above the still. Gravity feed water through condensers to tank below.
Water.jpg
Currently my keg over gas burner needs about 15 gallons an hour, so I need 45-60 gallons overhead to start a run.

If it were just for emergencies, you only need say 10 gallons...to keep cooling while you shut things down.

That diagram looks pretty simple and it's meant to be.

At the distillery, we'll have a 500 gallon water tower outside, feeds condensers, hot waste water goes to a pond, solar electric pump on a float switch replenishes water tower. A simple alarm sounds if water tower gets below 200 gallons.
CCVM http://homedistiller.org/forum/viewtopi ... d#p7104768" onclick="window.open(this.href);return false;" rel="nofollow
Ethyl Carbamate Docs viewtopic.php?f=6&t=55219&p=7309262&hil ... e#p7309262
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Canadian_Ice
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Re: Cooling flow failsafe?

Post by Canadian_Ice »

+1 To maritimer, ty he device you are looking for is indeed a flow switch. A flow switch can be wired up to open an electrical circuit when flow stops (wire it into your heater's circuit) or it can close an electrical circuit when flow stops (wire it into a circuit with a light, when flow stops the light will turn on)
Bobbywolf
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Re: Cooling flow failsafe?

Post by Bobbywolf »

Thanks everyone, a flow switch is indeed what I need. I need to set up my condensor so I can measure my output while running. When I'm doing a spirit run, a small trickle is all thats needed.

Almost all of the flow switches on ebay have a min rate of 1 L per min. I need to know if that is low enough.
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Re: Cooling flow failsafe?

Post by Maritimer »

Should be OK if you have more than 1 l/min flow. I don't use one of those flow switches myself, (use my homemade one) so maybe someone who does can comment on how they perform.

A basic principle of safety switches, relays, etc, is that they should be open-circuit when not being used and that the closed position allows events to happen.

Just to be doubly sure that the flow switch is working and hasn't become stuck closed, you could put two of them in series.

The flow switch should be positioned at the exit of the flow path so that any problem within the path will be detected.
Bobbywolf
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Re: Cooling flow failsafe?

Post by Bobbywolf »

Well, a quick test of running my condensor at spirit run speed, into a measured 3L container fills it in 6min 25sec.

That turns into a flow rate of 0.47L/min

There are a couple on ebay that have ratings down to 0.3L/min, (listed as coffee machine flow switches) but I'm thinking there may be a better way to go about it.

Off of my garden hose (at mains pressure, 35-50 psi or so, I drop down to a fine control valve where I adjust my flow to the condensor. I should be able to put a pressure switch here. If the well goes dry, or the well pump dies, the pressure will drop to near zero.

There is more than one way to skin a cat, and I just need to decide which way will work best for me.
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Re: Cooling flow failsafe?

Post by Maritimer »

One thing to consider would be using a recirculating system with a fan and radiator to remove the heat from the coolant.

Or you could return the coolant to the well.

Another principle of safety design is that you try as much as possible to monitor the parameter that you are concerned about, not some derived condition. For example, if you monitor the pressure before your control valve, you would not be aware of a coolant hose that has come undone feeding your condenser, or that the valve is clogged.
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shadylane
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Re: Cooling flow failsafe?

Post by shadylane »

NZChris wrote:An STC-1000 & a relay to switch off the power to the elements if the condenser outlet gets over the setpoint should do the trick fairly cheaply. This requires a start button and a circuit to latch the relay on until a fault breaks the circuit.
That's the easiest way I've found to do it.
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Re: Cooling flow failsafe?

Post by Bobbywolf »

That is a very true statement, you're right. Monitor the output of the condensor to know it has done its job.

I did find a couple low flow sensors. This one in particular is a solid looking unit and you can choose NO or NC contacts.
http://www.ebay.ca/itm/NEW-GEMS-SENSOR- ... SwF1dURPmT" onclick="window.open(this.href);return false;" rel="nofollow

These items are pricey. Most are way more expensive than this one.

The coffee type ones are actually flowmeters and not useable for my purpose.
Bobbywolf
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Re: Cooling flow failsafe?

Post by Bobbywolf »

shadylane wrote:
NZChris wrote:An STC-1000 & a relay to switch off the power to the elements if the condenser outlet gets over the setpoint should do the trick fairly cheaply. This requires a start button and a circuit to latch the relay on until a fault breaks the circuit.
That's the easiest way I've found to do it.
This is another option, except if you have no flow at all. Maybe a temperature sensor directly in the vent holes above the still head (boka). If cooling quits, hot vapour will start to exit the head, and trip the controller.

Hmmm
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Re: Cooling flow failsafe?

Post by Maritimer »

Bobbywolf wrote:Maybe a temperature sensor directly in the vent holes above the still head (boka). If cooling quits, hot vapour will start to exit the head, and trip the controller.
This is a good idea, but again, it uses a derived parameter. My sometime-to-be-finished complete safety system uses this as a redundant coolant-flow indicator on a VM still.

That's another principle of safety systems--redundancy. And the best way is to use two technologies watching and reacting to the physical system.

There might be such a thing as a bimetallic switch that could react to temperature. You would probably need a relay to remember that it has been tripped. Or maybe there are latching switches that need to be reset.
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Re: Cooling flow failsafe?

Post by cob »

Maritimer wrote: Or you could return the coolant to the well.
don't risk contaminating your well by putting ANYTHING back down the well.
be water my friend
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NZChris
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Re: Cooling flow failsafe?

Post by NZChris »

Bobbywolf wrote:
shadylane wrote:
NZChris wrote:An STC-1000 & a relay to switch off the power to the elements if the condenser outlet gets over the setpoint should do the trick fairly cheaply. This requires a start button and a circuit to latch the relay on until a fault breaks the circuit.
That's the easiest way I've found to do it.
This is another option, except if you have no flow at all. Maybe a temperature sensor directly in the vent holes above the still head (boka). If cooling quits, hot vapour will start to exit the head, and trip the controller.

Hmmm
Once you have built a latched circuit to keep the heat on, you can daisy chain as many stops into it as you want. Temperatures, timers, dead man timer, pressure sensors, flow meters, process refractometers, overflow sensors, anything that takes your fancy.
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Re: Cooling flow failsafe?

Post by Maritimer »

cob wrote:
Maritimer wrote: Or you could return the coolant to the well.
don't risk contaminating your well by putting ANYTHING back down the well.
Yes, good point.

NZChris wrote:Once you have built a latched circuit to keep the heat on, you can daisy chain as many stops into it as you want. Temperatures, timers, dead man timer, pressure sensors, flow meters, process refractometers, overflow sensors, anything that takes your fancy.
http://homedistiller.org/forum/viewtopi ... 0#p7086595 see Contactor Circuit Rev 1.pdf. Somehow all my pdfs got trashed.

For a full discussion: http://www.artisan-distiller.net/phpBB3 ... 30#p121545" onclick="window.open(this.href);return false;" rel="nofollow .
Last edited by Maritimer on Tue Apr 12, 2016 11:21 am, edited 1 time in total.
meatheadinc
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Re: Cooling flow failsafe?

Post by meatheadinc »

I have been useing a paddle/flow swich for sometime and highly recommend their use.
If my paddle switch is not triggered. I cannot power my elements
To get the sensitivity i was after i used a 5v paddle switch and ssr? That triggered a contactor block with both element. This enabled me to trigger muliple elements on different ciruits
.as the contactor block contained 4 nc and 4 no i also used it to trigger the alarm.
So far i havent had a coolant failure, but the alarm is a great reminder to turn on my recirculating systemand water cooler.
Pics on multiple fourms.
A paddle switch could also be used with gas to trigger a solenoid valve.
What goes up must come down, but a condenser helps
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shadylane
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Re: Cooling flow failsafe?

Post by shadylane »

""""Cooling flow failsafe""""
That's a good idea, without cooling water, alcohol vapor gets out of the still. :shock:
What happens if the cooling water flow is normal
But the heat controller fails wide open?
The failsafe using cooling water flow ain't a fail safe.
I prefer using the distillate temp at the end of the liebig.
If the balance between heat and cooling isn't right the heater turns off.
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Re: Cooling flow failsafe?

Post by meatheadinc »

@shadylane.
I also run an rc controller that regulate water temp. Head temp is also monitored. Both will also cut power at high temp.
A boiler low liquid level sensor will shut off power at low liquid depth to prevent damage to elements.
A spill sensor shuts the system down if cuts jars overflows.
Sounding safer...
These idea have been shared elsewhere but not here due to negativity toward anything electronic.
You can never make a still 100% safe and automated but i for one will do my best to incorporate all i can to make it as safe as possible
What happens if the cooling water flow is normal
But the heat controller fails wide open?
My output will increase and fill my jars quicker.. (CM plated column).
What goes up must come down, but a condenser helps
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Re: Cooling flow failsafe?

Post by Maritimer »

Maybe it's time to re-think HD's negativity toward safety sensors. If the time really does come when legislators are considering legalization, they are going to be questioning safety. If HD's response is, "The only way to ensure safety is to never leave the still unattended," imagine their response.

As meathead indicates, the whole state of the still must be monitored.

Shady, the OP is questioning coolant flow. Here is how I deal with SSR failure: http://homedistiller.org/forum/viewtopi ... 3#p7393476 . That is a separate problem from coolant flow.

What say we at HD design a safety system, leaving ideology behind and getting real?
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Kareltje
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Re: Cooling flow failsafe?

Post by Kareltje »

Maritimer wrote:Maybe it's time to re-think HD's negativity toward safety sensors. If the time really does come when legislators are considering legalization, they are going to be questioning safety. If HD's response is, "The only way to ensure safety is to never leave the still unattended," imagine their response.

As meathead indicates, the whole state of the still must be monitored.

Shady, the OP is questioning coolant flow. Here is how I deal with SSR failure: http://homedistiller.org/forum/viewtopi ... 3#p7393476 . That is a separate problem from coolant flow.

What say we at HD design a safety system, leaving ideology behind and getting real?
Yeah, you make a very valid point.

I have a air cooled condenser. I want my systems to be safe on their own right. The only problem in my system is the influx of natural gas from the grid. And of course I have to have a receptacle for my distillate that is large enough.

I thought about water cooled condensers in various designs. But first and foremost I wanted it to be failsafe. So a system like DAD300 showed, would be my design. Gravity works always, is failsafe.
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Re: Cooling flow failsafe?

Post by ej9071 »

Kareltje wrote:
Maritimer wrote:Maybe it's time to re-think HD's negativity toward safety sensors. If the time really does come when legislators are considering legalization, they are going to be questioning safety. If HD's response is, "The only way to ensure safety is to never leave the still unattended," imagine their response.

As meathead indicates, the whole state of the still must be monitored.

Shady, the OP is questioning coolant flow. Here is how I deal with SSR failure: http://homedistiller.org/forum/viewtopi ... 3#p7393476 . That is a separate problem from coolant flow.

What say we at HD design a safety system, leaving ideology behind and getting real?
Yeah, you make a very valid point.

I have a air cooled condenser. I want my systems to be safe on their own right. The only problem in my system is the influx of natural gas from the grid. And of course I have to have a receptacle for my distillate that is large enough.

I thought about water cooled condensers in various designs. But first and foremost I wanted it to be failsafe. So a system like DAD300 showed, would be my design. Gravity works always, is failsafe.
This is an interesting topic. In order to have the adequate safety devices in place, we need to identify the situations and the "What-if's". Taken from the Process Hazard Analysis mindset. In this case, we are asking, "What if there is a low/no flow of cooling water?" We can then list the outcomes or consequences from that situation. From there, we can list the safeguards in place already and come up with recommendations.

I would say first and foremost is to have a quantifiable way of seeing if you have water flow. If you are not running cooling pumps, a simple flow indicator is the cheapest way to go (following the logic of not leaving the area while distilling). In the event that you do lose water flow simply killing the heat will slow or stop the distilling process rather quickly. Obviously there are multiple ways to design safety into this "what-if" item, but it boils down to (pardon the pun) how much money you are wiling to spend.
It is no use doing what you like; you have got to like what you do. - Winston Churchill
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