Self Circulating Boiler?

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Self Circulating Boiler?

Post by Hounddog1 »

I have a 1/2 barrel keg boiler with electric element and was considering adding 2 1/2” ports for circulation. Suction side near the bottom and output near the top with a high temp pump to circulate similar to some brewing systems. Wondered if anyone here had any thoughts or suggestions. Appreciate any help.
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Re: Self Circulating Boiler?

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For what purpose
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Re: Self Circulating Boiler?

Post by Rrmuf »

Interesting idea but I am unsure what it would accomplish? Are you trying to solve a problem? If not, you're just creating a potential for problem.
E.G. Some still runs can involve putting solids in the boiler and could clog up your pump.
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Re: Self Circulating Boiler?

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My thought was that it may keep the wash circulating for better heating efficiency and to help avoid scorching. I don’t know if it would actually help or not but that is why I am considering doing it. My thought was that it could sort of work as an agitator.
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Re: Self Circulating Boiler?

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And no I don’t plan on having solids in the boiler because yes I can see that would relate a huge problem.
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Re: Self Circulating Boiler?

Post by still_stirrin »

Hounddog1 wrote: Wed Jan 19, 2022 6:34 am… keep the wash circulating for better heating efficiency…
You’ll lose more heat in the piping network than you’ll save in the boiler. Plus, you’ll have to contend with high temperature seals in the pump head … more trouble than worth.

Larger commercial boilers utilize an agitator to stir the slurry while heating. Even those have “issues”. For a hobbiest, there really aren’t any elegant, low budget solutions other than steam injection.
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Re: Self Circulating Boiler?

Post by Rrmuf »

Hounddog1 wrote: Wed Jan 19, 2022 6:36 am And no I don’t plan on having solids in the boiler because yes I can see that would relate a huge problem.
... I add botanicals to my boiler so it would be an issue for me.

In any event, good on you for asking: you got some answers. :-)
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Re: Self Circulating Boiler?

Post by Hounddog1 »

:thumbup: Thanks for the input!
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Re: Self Circulating Boiler?

Post by Setsumi »

Myself have a boiler with a large space below the heater element due to a concave bottom. The liquid below the heater does not heat up the same as above the heater, although i believe it does get homogeneous at full boil.

Myself would like an internal self driven stirrer. Sometimes i think on the lines of a ferris wheel. But i am not certain it will turn...?
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Re: Self Circulating Boiler?

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Setsumi wrote: Wed Jan 19, 2022 11:36 am Myself have a boiler with a large space below the heater element due to a concave bottom. The liquid below the heater does not heat up the same as above the heater, although i believe it does get homogeneous at full boil.

Myself would like an internal self driven stirrer. Sometimes i think on the lines of a ferris wheel. But i am not certain it will turn...?
Vertical pieces of copper might work as a sort of heat-pipe to help pull the heat down. I have exactly the same problem with my boiler and had been wondering about how to add an agitator without bankrupting me, or allowing vapours to escape. A framework of copper tubes might well work as a way of passively redistributing heat, relying on copper's inherent ability to distribute heat uniformly.

I've got a failed attempt at a coil kicking around. I might see if I can't salvage some material from it and make a prototype.
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Re: Self Circulating Boiler?

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If you put the element close to the bottom, convection will take care of it for you. I can barely get my fingers under my bottom element.
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Re: Self Circulating Boiler?

Post by NormandieStill »

It's not always possible to get the element lower. With a 30L Euro keg (which are relatively stubby), you have three options.

1) Go in from the bottom and bend the element
2) Go in from the side (As low as possible without hitting the seam) and bend the element down (less bending than option 1, but greater risk of running dry).
3) Find some way of forcing circulation

Option 1 has been on my mind for a while, but even with a heavily angled ferrule connection (which will be a pain to solder) it's going to involve at least a 30 degree bend.
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Re: Self Circulating Boiler?

Post by Hounddog1 »

I guess my thinking was keeping the wash always moving with a pump sort of like a hot tub with jets. I didn’t consider having to replace pump seals often and maybe it’s not worth the trouble but I wonder if having multiple outputs or “jets” to keep it always moving would actually be of some benefit. Just a thought. :thumbup:
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Re: Self Circulating Boiler?

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Pumps and jets etc. is a lot of trouble to go to because the element is in the wrong place.

I formed the bottom of the still so that the element enters at 45 degrees and is bent 45 degrees. One and a half liters covers it, so I never have to worry about circulation or running it dry.
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Re: Self Circulating Boiler?

Post by ThomasBrewer »

The turbidity caused by boiling will negate any stratification.
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Re: Self Circulating Boiler?

Post by Twisted Brick »

.
An agitator has been done successfully, albeit with a gas-fired still. A wash thin enough to be run successfully on elements shouldn't need an agitator, but why couldn't one fab up a horizontal version of the one in the build thread? Go through a tri-clamped 2" ferrule on the side of the boiler just above the element. Fix 4 or 5 rows of angled blades on a shaft that would extend to the middle of the boiler. Angled strategically, the agitation might even help keep the wash moving over the elements.

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Re: Self Circulating Boiler?

Post by Setsumi »

NZChris wrote: Wed Jan 19, 2022 2:33 pm Pumps and jets etc. is a lot of trouble to go to because the element is in the wrong place.

I formed the bottom of the still so that the element enters at 45 degrees and is bent 45 degrees. One and a half liters covers it, so I never have to worry about circulation or running it dry.
Some boilers just do not allow certain installations to be on the bottom. I have a ss pool filter with a very convex bottom. I have a triclamp heater installation that was soldered. With my soldering skills i had to place it on a surface where i could solder it. You say 'wrong place' but to me it was the only place. It works BUT this discussion might lead to interesting solutions to get the volume below the heater quicker in suspension.
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Re: Self Circulating Boiler?

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Setsumi wrote: Wed Jan 19, 2022 8:54 pm Some boilers just do not allow certain installations to be on the bottom.
'Impossible' only means that you haven't found a solution yet. I hand shaped a copper bottom for my first still over thirty years ago and I'm very grateful that I went to the trouble. You only have to do it once.
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Re: Self Circulating Boiler?

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Hounddog1 wrote: Wed Jan 19, 2022 6:34 am My thought was that it may keep the wash circulating for better heating efficiency and to help avoid scorching. I don’t know if it would actually help or not but that is why I am considering doing it. My thought was that it could sort of work as an agitator.
You would only need this to run until the element had boil action going. At that point it takes care of itself.
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Re: Self Circulating Boiler?

Post by Dancing4dan »

Would a chigger pump take the heat?
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Re: Self Circulating Boiler?

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.. I still don't get why this is beneficial at all.
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Re: Self Circulating Boiler?

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Dancing4dan wrote: Thu Jan 20, 2022 5:42 am Would a chigger pump take the heat?
Sure, chugger or march work; but as soon as you get near a boil they will start to malfunction, they don't do boiling well. Of course once your boiling the beer moves itself.

I don't see a point either. You recirculate in brewing to ensure you have a uniform temp, the gradient between the top and the bottom of the pot at 160 can be pretty large. Once you talk boiling its self circulating. On a very large batch (many bbl) it very likely helps with heat up speed and gradient enough to make it worth while. In our relatively overpowered, small 15-30 gallon systems it seems like the money and effort would be much better spent on your brew rig.
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Re: Self Circulating Boiler?

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Rrmuf wrote: Thu Jan 20, 2022 5:47 am .. I still don't get why this is beneficial at all.
Heat rises, so the closer the element is to the top of the charge, the more likely it is that the turbulence wont be enough to circulate the heat to the bottom of the still.
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Re: Self Circulating Boiler?

Post by Rrmuf »

I am asking why is there any (potential) benefit to having a pump cisculate the boiler load?
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Re: Self Circulating Boiler?

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Maybe there isn’t any benefit. I guess that’s what I was asking as well.
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Re: Self Circulating Boiler?

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I don’t know of any potential benefits unless the element is badly placed.
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Re: Self Circulating Boiler?

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Ben wrote: Thu Jan 20, 2022 12:55 pm
Dancing4dan wrote: Thu Jan 20, 2022 5:42 am Would a chigger pump take the heat?
Sure, chugger or march work; but as soon as you get near a boil they will start to malfunction, they don't do boiling well. Of course once your boiling the beer moves itself.

I don't see a point either. You recirculate in brewing to ensure you have a uniform temp, the gradient between the top and the bottom of the pot at 160 can be pretty large. Once you talk boiling its self circulating. On a very large batch (many bbl) it very likely helps with heat up speed and gradient enough to make it worth while. In our relatively overpowered, small 15-30 gallon systems it seems like the money and effort would be much better spent on your brew rig.
Like I said. It wouldn’t be needed after boil started
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Re: Self Circulating Boiler?

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Ok. Good question hounddog, even if we don't see a benefit. Thanks.
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Re: Self Circulating Boiler?

Post by Ben »

NZChris wrote: Thu Jan 20, 2022 3:33 pm I don’t know of any potential benefits unless the element is badly placed.
Put the element in the right spot to begin with, problem solved. It needs to be as low in the vessel as possible anyway, that way your not dry firing if you have a smaller charge.
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Re: Self Circulating Boiler?

Post by Hounddog1 »

Thanks all. Great info
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