Blew my top!

[NY Chris]

I recently had an experience I won't soon forget. I have run my pot still a few times without any problems, cleaning runs and sacrificial alcohol run all went well without a hiccup.
I have a homebuilt pot still that has a lid and lyrn arm to a worm in a bucket condenser.The lid is just inserted into the collar on the top of the pot and I have been sealing it with flour paste. Always worked great.
Yesterday while running a wash I was getting it up to temperature and starting drip. Just then the lid blew off the pot!!!
a waterfall of fire seened to roll out and across the floor. I quickly shut down the propane and extinguished the fire or (vice versa i cant remember) with a water extinguisher, which extinguished the fire instantly, as fast as the fire started it was extinguished, happened so fast I can bearly remember the details. Just glad I wasn't standing close by or I may have gotten burned.

After changing my underwear, I think I may have narrowed down the problems I had that day.

1) The flour paste I made may have been made with too much water and took to long to cook and form the seal.
2) I may have been running the still to hard, creating to much steam and overpowering my set up.

I came to this conclusion after a successful run the same day after changing to a dryer paste mix and running the still much slower, the still ran good with the cap staying on the whole run.

Does anyone have any ideas that would increase the safety while operating this type of setup.
The design I am using is the still plan from the book Moonshine! By author Matthew Rowley
I have made one modification to the plan. I have extended the lyrn arm by about 6 feet using 3/8 copper tubing to keep my finished product further away from the propane burner.
Thanks
Chris

[rtalbigr]

Chris, your system should not build pressure at all, it should be an open system, so you have some kind of blockage somewhere.

Is your worm in totally downward spiral? A flat spot where liquid could puddle could be a problem.

The 3/8 extension could be too small to handle the amount of vapor going through it building pressure.

Did you overfill your pot so when it got to temp it puked blocking vapor somewhere in your arm?

Once again, your system should be completely open, no pressure build up!

Big R

[Prairiepiss]

+1 Big R.

Tell us more about your still. What its made from? Sizes dimensions? A pic would be good.

[heartcut]

What they said. Glad you're OK.

[NY Chris]

I tried uploading a photo but the file is to large.
I will upload a photo asap
I will check the worm, I notice the worm doesn't drain on it's own, I always need to blow through it ,not too hard but a little, to clear any rinse water, it is definitely pudding somewhere in there.
Could that slight amount of restriction be the problem?
I only filled the pot with about 4 gallons ,the pot can hold about 7.5 gallons.

I am using a turkey fryer jet type burner, are you guys saying I should be able to run full blast on that burner and not build up any pressure if my system is designed and running properly?
I am also going to increase my lyrn arm extension piece maybe to 1/2 or 3/4 then reduce at the worm condenser.

Thanks
Chris

[Prairiepiss]

As for a safety stand point. Yes you should be able to run it full blast and not have pressure build up. LM a good practices stand point you should never have to run it that hard.

What size is your worm? It needs to be 3/8" min preferably 1/2". And if its holding liquid that's not good. That means there is a high point or its too small. Or even worse both.

[rtalbigr]

I am using a turkey fryer jet type burner, are you guys saying I should be able to run full blast on that burner and not build up any pressure if my system is designed and running properly?

Thanks
Chris

As for a safety stand point. Yes you should be able to run it full blast and not have pressure build up. LM a good practices stand point you should never have to run it that hard.

What size is your worm? It needs to be 3/8" min preferably 1/2". And if its holding liquid that's not good. That means there is a high point or its too small. Or even worse both.

From a safety standpoint what Mr. PP said is absolutely true. From a realistic standpoint you need to learn how your still reacts and operates under different situations. Doing a strip run is going to be different from doing a spirit run and will require different energy input.

But first ya definitely need to fix your problems.

When you're ready to start distilling again start out slow and learn what your still can handle. The amount of energy required is going to continually change depending on what's in your pot and where you are in the run.

Big R

[NY Chris]

I understand
I'm going to check the worm and be sure it drains properly as a first fix then maybe use a larger diameter extension on my lyrn arm.
I'm going to get a couple of picks up soon, maybe tomorrow.
Thanks again.

[NY Chris]

th.jpeg (19.43 KiB) Viewed 4551 times

If anyone is familiar with this book, I built the still to the exact specs from this book. Anyone else using this still?
Just wondering how it's working for you?

[rtalbigr]

My still is built on the basic design from that book with some minor mods. I know of a couple of individuals who have similar stills. It's a good simple pot still and works well. I really like the traditional concept of a caped top. It will serve you very nicely for years and with care will produce some wonderful drinks.

Big R

[NY Chris]

Good to here Big R.
I'm new to this and just trying to work out the kinks.
It's nice to know the still makes some good drinks when run properly.

[rad14701]

I'm leaning more towards the rapid expansion and no mechanical fasteners holding the lid down as the most probable cause for your near disaster... I haven't nor will I ever run a still without some form of mechanical fastening to keep the boiler lid where it is supposed to stay...

[HookLine]

I wouldn't use anything smaller than 1/2" (OD) for the vapour path or a worm condenser in a pot still.

3/4" would be my choice.

[NY Chris]

Rapid expansion sounds very very likely, I was really heating it hard.
I ran two 4 gallon batches of All bran last night, started heating it pretty hard to get warm up, then as soon as I felt heat running down the arm I backed the heat way back, just enough to keep a very thin pencil lead size stream flowing.
The still worked very nice this time.
Almost peed my pants this time when I tasted how good it is.
I have attached some picks of my still set-up.
I do have a minor modification to the plan in the book, I had brazed an arm support and the arm was clamped to the support at the time of the incident but still popped up.( I didn't like it floating in the breeze either, just seemed it might get knocked off).
I also had the arm extension piece shown in the pics on at the time.
During my successful run last night I had it set up as in the pic. With no extension attached and flour paste sealing the cap.
I have attached some pic

Thanks for all the help , i couldn't have done it alone.

[NY Chris]

Before my next run I'm going to a 1/2 " condenser coil and increase my arm size.
Thanks Hookline

[NY Chris]

Hit it right on the head.
Rapid expansion!!!
Nothin like learning the scary hard way.
Thanks Rad.

[Stillatryin]

I've yet to make a run with my beer keg still. I'll be running it initially as a simple pot still. The pipe exiting the still will be 3/4 dia. Same pipe that siphons the beer out of the bottom. I was contemplating making a clamp to hold it in, but that seems dangerous. The pot will never be more than 2/3ds to 3/4 full
and my mash/wash will be strained completely. Should I install some sort of pop off valve?

[NY Chris]

From what I've read on this site you shouldn't need a pop off valve but I have a whole 5 runs under my belt.
Also there is special hardware available to connect the still parts to your keg, just do some internet searches.
If I had one I think I would have still had a fire due to the fact I was heating with an open propane flame.
Probably safer to heat with a hot plate or other electric heating device but I like the control I have with a flame.
Good stillin

[Stillatryin]

Thanks Chris, I'd like to hear from one of the veterns on this subject. BTW, I like your still. It looks like it came from the days of my papaw. I've got a 5' tube of solid stainless that just a fuzz .09 larger than 2" I.D. I'm looking forward to the day that I get some guts for it. I know Mile Hi makes alot of hardware for this beer keg rig. I suppose there are others even more reasonable. As for hot plates, this thing is 15.5 gallons, I'm pretty sure we're going to be forced to use propane. As Hank Hill says, "God's Gas".... I guess if hot plates were twice the size of the one's I've seen, they may work.

[NY Chris]

Thanks for the compliment on my still, so far aside from the top blowing off and scaring the crap out of me ,it makes some mighty fine whisky.

I'm thinking of using a couple of springs keep my cap secure, just got to figure how to mount them.

I was hoping one of the vets would jump in and give you some good advise. I am surely a noob.
I have thought about some type of relief valve but just can't come up with a safe way to keep the expelled vapor from igniting.
As soon as it blows off it's going to hit the flame of the burner and start a fire.
I have thought about a pressure gauge, it could be installed vapor tight, you could look at it once in a while and it may give an indication of rising still pressure. You could respond by turning down the heat or putting your fingers your ears and closing your eyes, your choice but at least you would have some indication of rising pressure risk.
I would like to know what some of the veterans think of the pressure gauge idea. Going a little further I'm sure some company makes a pressure alert system with a sensor and some type of alarm, is there an app for that ,i know money is always an issue but safety must always come first.
Good luck to ya,
Chris

[Prairiepiss]

If a still is built correctly there shouldn't be a need for a pop off valve. 3/8" tube minimum will give a good enough vapor path to not get clogged. And most pop off valves are much smaller then that. So they would get clogged before the 3/8 tube would.

Stillatryin you would be much better off if you started you own thread. So this one doesn't get hijacked. And you can get the best answers for you.

[NcMoonLight]

Im glad that your okay! It seems that if you were standing a few feet closer you would have been burnt pretty bad. Im happy to hear the modifications are working great for you, I was thinking to myself about your situation and was wondering if you flanged the boiler and the pot head and used a tri-clamp wouldnt that still create a airtight seal AND could be removed to clean the still/etc..

Anyway, that was just a thought that popped in my head. Otherwise just keep using the flour mix, just prefect the mixing haha

[Buckshot]

You need to put some kind of weight on that cap to keep it from blowing. We always put a big ol rock on it for safe measure. I've known a couple of people ended up in the burn ward from a blown cap. you gotta be careful and make sure there's no blockage. 1/2" will let a grain of corn through if it pukes.

[NY Chris]

Thanks buckshot
I'm working on a plan to keep it down with a couple of springs, just got to braze on the spring mounts.

[sunshine4me]

so for clarity, the solution to this problem would be to always clamp down the lid and slowly heat the rig up? correct? (given you've properly the built still of course)

[Highrisen]

Some folks mentioned a low spot in the worm as a suspect to the pressure build up. I would think a secure lid would hold enough pressure to blow the puddle out rather than blow the still apart.

[buflowing]

consider superheating (think its called bumping). A localized hot spot on a suspended solid causing rapid vapor generation. Did you hear a rumble in your boiler just before it blew? Boiling chips will remedy or reduce occurrence.

[Dnderhead]

when something boils the bubbles form on any rough spots inside the boiler and help circulate whatever is in it.
now if you have a smooth boiler like a glass beaker, bubbles have no place to form.
therefor the liquid does not circulate and "super heats" or heats above the boiling point.now when the liquid reaches the gas stage it erupts violently.this is "bumping"
this can be see when heating water etc. in a microwave but for a bit diferant reason,a microwave heats "in spots" and not evenly.

[buflowing]

Thank you for the correction.