Boilers and pressure

[PalCabral]

I realize I have created a few threads already on the topic of boilers, I am sorry to be a bore.

Boilers kinda comes in two basic variants, right? You have the purpose-built distillation boilers which are made/welded into one piece, with ports giving access the inside of the boiler, e.g. milk can boilers and keg boilers. If built well, the advantage is quality, these things will last for years. However, as you grow in size and start getting up to 100L/26g volumes, they are also becoming more expensive considering the work and steel that goes into the construction.

Then there are the pot boilers with a detachable lid, a much more simple design where the lid is kept in place by clamps of different sorts. These are often re-built restaurant or mashing pots and comparatively cheap, especially when you go up in volume. The advantage besides price is the easy access to the inside of the boiler and the possibility to fit a false bottom and to re-use the pot as a mash tun. However, the lid is also the weak spot. The clamps needs to hold the lid tight, and a good sealing gasket is needed to avoid leaks, and I have my doubts about the life-expectancy of the clamps themselves. The lid also needs to be made in thick sturdy metal, both to fit snug but also to hold the weight of all still head components that are going to sit on top of it. All-in-all, this type of construction may come with issues if the construction is not great.

What kind of pressure does a boiler need to handle in distilling? Say we are talking about 60-100L/20-30g of wash and 5-6kw of power (or more). I am tempted to try to build a boiler from a 100L pot with a detachable lid myself, or find someone who can help me build it, but I realize I don't know what forces a boiler needs to be built for. Another thing is the shape of the lid. I am assuming a bulging, dome-shaped, lid deals with the pressure better than a completely flat lid?

Thoughts?

[Yummyrum]

If it’s just a pot still , there will be very little pressure .
If it’s connected to a thumper , there might be maybe 0.2 psi .
If you are steam stripping a thick mash , you could get just over 1PSI

Your results may vary .

[Copperhead road]

The only pressure I got from a full Copper 100L boiler, was from the missus….. me wanting to spend $8000 on the boiler caused a lot of pressure with the Mrs. lol

[SW_Shiner]

As yummy said. There should be very little pressure is the boiler of a well designed still. Any pressure is going to come from the vapour not being able to escape fast enough. Provided your vapour path is of adequate size, you shouldn't have any issues with pressure.

A good place for more reading might be the steam distilling and thumper sections. From memory, there's quite a bit of discussion around boiler pressure with people looking to purchase safety relief valves.

[Saltbush Bill]

There should never be pressure in any boiler, that is why all stills should always be built so that they are at all times open to atmosphere.
If you have pressure your doing something wrong.

[googe]

What saltbush bill said.

[Copperhead road]

Absolutely what Salty said.

[PalCabral]

The only pressure I got from a full Copper 100L boiler, was from the missus….. me wanting to spend $8000 on the boiler caused a lot of pressure with the Mrs. lol

I would expect that type of pressure from my dear wife too

[PalCabral]

Thanks for the responses, it makes sense that the pressure can't build up as the vapors are allowed to escape through the still head. I guess I wasn't using my grey cells this morning.

[Yummyrum]

Build yourself a simple manometer Pal , it is interesting to observe pressure buildup . A simple google search of inches of water displacement will tell you the PSI so you can calibrate it .

[Windy City]

It' pretty simple math
1' of water column is 0.036 psi.
If you figure 1" for one plate (rounding up) each plate is 0.036 psi so 4 plates = 0.14 psi
If your thumper holds 12" then it is 0.43 psi
And if you have a pot still it should be Zero psi

[BigSwede]

Thanks for the responses, it makes sense that the pressure can't build up as the vapors are allowed to escape through the still head. I guess I wasn't using my grey cells this morning.

Given no real pressure buildup, I think the two things to worry about converting a big commercial vessel is structural strength, and a lid gasket that is non-toxic and reasonably leak proof. A crummy rubber (or no) gasket can be replaced with a handmade pure silicone job cut from an inexpensive sheet of silicone stock.

[Salt Must Flow]

I realize I have created a few threads already on the topic of boilers, I am sorry to be a bore.

Boilers kinda comes in two basic variants, right? You have the purpose-built distillation boilers which are made/welded into one piece, with ports giving access the inside of the boiler, e.g. milk can boilers and keg boilers. If built well, the advantage is quality, these things will last for years. However, as you grow in size and start getting up to 100L/26g volumes, they are also becoming more expensive considering the work and steel that goes into the construction.

Then there are the pot boilers with a detachable lid, a much more simple design where the lid is kept in place by clamps of different sorts. These are often re-built restaurant or mashing pots and comparatively cheap, especially when you go up in volume. The advantage besides price is the easy access to the inside of the boiler and the possibility to fit a false bottom and to re-use the pot as a mash tun. However, the lid is also the weak spot. The clamps needs to hold the lid tight, and a good sealing gasket is needed to avoid leaks, and I have my doubts about the life-expectancy of the clamps themselves. The lid also needs to be made in thick sturdy metal, both to fit snug but also to hold the weight of all still head components that are going to sit on top of it. All-in-all, this type of construction may come with issues if the construction is not great.

What kind of pressure does a boiler need to handle in distilling? Say we are talking about 60-100L/20-30g of wash and 5-6kw of power (or more). I am tempted to try to build a boiler from a 100L pot with a detachable lid myself, or find someone who can help me build it, but I realize I don't know what forces a boiler needs to be built for. Another thing is the shape of the lid. I am assuming a bulging, dome-shaped, lid deals with the pressure better than a completely flat lid?

Thoughts?

Dome lids are fancy because they make room for potential foaming. You can do a flat lid, but there wouldn't be any added room for foaming (if any occurs).

[shadylane]

What kind of pressure does a boiler need to handle in distilling? Say we are talking about 60-100L/20-30g of wash and 5-6kw of power (or more). I am tempted to try to build a boiler from a 100L pot with a detachable lid myself, or find someone who can help me build it, but I realize I don't know what forces a boiler needs to be built for. Another thing is the shape of the lid. I am assuming a bulging, dome-shaped, lid deals with the pressure better than a completely flat lid?

Thoughts?

The boiler pressure will depend on power and how much restriction the plumbing and condenser causes.
For example, I have a 18gal pot with 1" ID plumbing and liebig @ 6kw the pressure will bounce around 3" of water column. 0.1ish psi
It doesn't take very much structural strength to keep a boiler together, even one made from 16oz roofing copper can do the job until something goes wrong. Most likely failure will happen due to a vacuum instead of over pressure.

A tape measure and calculator will tell how much force is trying to lift the lid off.
A 16" dia lid will have 20 pounds trying to lift it up @ .1psi
My preference for sealing a removable lid is to use a water seal.

[shadylane]

Build yourself a simple manometer Pal , it is interesting to observe pressure buildup . A simple google search of inches of water displacement will tell you the PSI so you can calibrate it .

A mano will not only measure the pressure, it will also work as a safety relief valve.

[PalCabral]

The boiler pressure will depend on power and how much restriction the plumbing and condenser causes.
For example, I have a 18gal pot with 1" ID plumbing and liebig @ 6kw the pressure will bounce around 3" of water column. 0.1ish psi
It doesn't take very much structural strength to keep a boiler together, even one made from 16oz roofing copper can do the job until something goes wrong. Most likely failure will happen due to a vacuum instead of over pressure.

A tape measure and calculator will tell how much force is trying to lift the lid off.
A 16" dia lid will have 20 pounds trying to lift it up @ .1psi
My preference for sealing a removable lid is to use a water seal.

Since I am never using anything lower than 2" pipe components and I am not using a steam rig or any retorts, over/under-pressure, I should probably not have to worry about too much pressure. But 10 kilos pushing the lid, as in your example, is still a lot in my view.

I remember you have mentioned water seals before, Shady. I'll search to check out about how that works. It requires some sort of jacket or collar at the brim?

Dome lids are fancy because they make room for potential foaming. You can do a flat lid, but there wouldn't be any added room for foaming (if any occurs).

Yes, this is of course the reason. Adding a bit of head room for foaming is main purpose. I should have thought about that. I keep having these issues a lot myself.

[shadylane]

I remember you have mentioned water seals before, Shady. I'll search to check out about how that works. It requires some sort of jacket or collar at the brim?

The pretty copper porn water seal lids look like this. The downside is it can't holdback enough pressure to drive a column or thumper.

[PalCabral]

Speaking of boiler lids, this is a construction I found on a site for selling used stuff. This was sold under the category brewing equipment as a mash tun, but it was the lid that caught my eye. The lid is held in place by wing nuts and the two holes are 2”. I dont think I’ve seen this type of lid used for mashing before but I’ve seen it elsewhere..,

The seller is the daughter or relative of the owner, who I suspect has passed away, so she couldnt answer many questions. I believe it was a project more than a finished mash tun and it’s not possible the old man was an aspiring HD member? In Sweden you can find really creative designs to produce the good stuff, including boilers made from plastic buckets…

Not sure what kind of steel it is, but she’s selling the whole thing for 50 USD.

IMG_8284.jpeg

IMG_8285.jpeg

Thinking about the old owner of the mash tun, I realized that at some point one of mine will try to sell all the shit I have accrued only in these last 1 1/2 years. How they are going to sell the still I don't know and the worst thing is they dont know the first thing about my set up. Not my problem obviously but I would like that my stuff ends up with someone who appreciates what we do and that my kids make a few bucks on the sale too. Sorry for getting a bit dark here.

[Yummyrum]

That lid method with the studs and wing nuts was popular twentyish years ago . It was often done with a keg and the lid cut off another keg to keep a 2” sanke connection . Or more commonly , a big SS Salad bowl .

The gasket material was always questionable or never mentioned

That particular setup with the two 2” holes screams Thumper .

[Username]

Not my problem obviously but I would like that my stuff ends up with someone who appreciates what we do and that my kids make a few bucks on the sale too.

The big fear, with our toys and whatever other hobbies we all got is that the equipment get sold for less than the price than we claimed to have bought it for originally

[MooseMan]

Do you have your eye on a vessel in particular then Pal?

[PalCabral]

Do you have your eye on a vessel in particular then Pal?

Since I will not do an upgrade from my current set up until next year, I am only in an exploration phase at the moment, and tbh all over the place, so no, not really. I want a boiler with a capacity minimum of 75 liters of wash plus the necessary head space, so 85-110 liters. I like the pot-with-detachable-lid models, especially if they come with a false bottom, as I think it would ease my mind when it comes to stripping fruit washes. If it could double as a big mash tun even better. But the hatch/clamp held lids make me a bit uneasy. The alterative is a 100 liter milk can, better quality but more expensive.

I am planning to keep my 50 liter boiler for spirit runs.

[PalCabral]

That particular setup with the two 2” holes screams Thumper .

I was thinking steam distilling

[PalCabral]

Not my problem obviously but I would like that my stuff ends up with someone who appreciates what we do and that my kids make a few bucks on the sale too.

The big fear, with our toys and whatever other hobbies we all got is that the equipment get sold for less than the price than we claimed to have bought it for originally

Yeah, I know. At the same time, I’ll be lynched if I tell the family how much I spent on all the shit

[Yummyrum]

That particular setup with the two 2” holes screams Thumper .

I was thinking steam distilling

Hell yeah

Buy it

[MooseMan]

Ah ok, I thought maybe you had found something as a potential boiler.

I got incredibly lucky to find the jumbo kegs that I built my latest boiler out of. Have you done any digging to see if you can maybe find one?

I know you like the open lid idea but a 4-6" fill port gets you inside the boiler easily enough.

All depends how much you want to spend, and how much work you want to do on it I guess.

Edit: I remember commenting on a thread about Amazon 26g milk cans where someone here built a rig on one.
They were cheap, but I think a bit thin?

If I didn't have the boiler I do, I'd go for one of those, and reinforce the areas that needed it by soldering patches on etc.

Re-edit!
Quick Google just found this.

Professional Stainless Steel Dustbin 100 Litres | Adexa SDB95 https://share.google/GCLN9VypYYvyiveRh

I know you're not in the UK but I'm sure you'll find similar. That's cheap!

[BigSwede]

Not my problem obviously but I would like that my stuff ends up with someone who appreciates what we do and that my kids make a few bucks on the sale too.

The big fear, with our toys and whatever other hobbies we all got is that the equipment get sold for less than the price than we claimed to have bought it for originally

I'm at peace with the fact that everything I have in copper will be probably sold for scrap. I've had my fun with it. "What's this weird plumbing pipe with lots of little tubes inside?" Maybe the guys at the scrap yard will recognize and adopt some of the stuff. That would be fine.

As for my machine tools and tooling, there's pieces in there worth quite a few bucks, but are unrecognizable by laymen. I'm hoping to arrange something like "HOBBY MACHINISTS! Free shit, all you can haul away! Use it!" instead of just seeing it go to a scrap yard.

[BigSwede]

Quick Google just found this.

Professional Stainless Steel Dustbin 100 Litres | Adexa SDB95 https://share.google/GCLN9VypYYvyiveRh

I know you're not in the UK but I'm sure you'll find similar. That's cheap!

Mooseman, I'm 99% sure that'd be fine, but I think we need to be aware of stainless alloys that aren't considered food grade. If it's not 304 or 316, I'd be slightly leery. There are inexpensive dropper chemical test reagents available to identify if an alloy is 304.

Mislabeled steels come out of Asia all the time. There was a guy who bought an expensive maple syrup boiler cheap that was supposed to be 304, it was labeled 304, but it wasn't. He had to scrap it.

Something to keep in mind...

[PalCabral]

Quick Google just found this.

Professional Stainless Steel Dustbin 100 Litres | Adexa SDB95 https://share.google/GCLN9VypYYvyiveRh

I know you're not in the UK but I'm sure you'll find similar. That's cheap!

Mooseman, I'm 99% sure that'd be fine, but I think we need to be aware of stainless alloys that aren't considered food grade. If it's not 304 or 316, I'd be slightly leery. There are inexpensive dropper chemical test reagents available to identify if an alloy is 304.

Mislabeled steels come out of Asia all the time. There was a guy who bought an expensive maple syrup boiler cheap that was supposed to be 304, it was labeled 304, but it wasn't. He had to scrap it.

Something to keep in mind...

That is cheap, Moose. I am on the lookout for theE type of pots but 100 liters usually land at 250 euros or theresbouts.

But Bigswede is tight. How to know it’s proper steel or not?

[BlackStrap]

That lid method with the studs and wing nuts was popular twentyish years ago . It was often done with a keg and the lid cut off another keg to keep a 2” sanke connection . Or more commonly , a big SS Salad bowl .

The gasket material was always questionable or never mentioned

I wouldn't say always... I use a flour water paste (the consistency of a soft thick fettuccini noodle) and with a coating of olive oil on the mating surfaces for easy cleanup at the end of the run.

That particular setup with the two 2” holes screams Thumper .

Since these photos I've added a 2" port for charging the boiler after the fore's are collected. This is handy for "breaking" the seal when shutting down to keep from collapsing the boil when cooling. (If interested I'll add some photos?)

Popular and still producing some good spirits...

IMAG0712.jpg

Catch the full story here, and those in this group that inspired my build.
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