Column height vs. packing

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rockymars
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Column height vs. packing

Post by rockymars »

Hey all,

A total noob question about column height to achieve azeo.

I’m planning to build a modular 2” CCVM still using tri clamp sections, Meccano style.

I’m aware that the column height is quoted in a range of 1:15-1:24 of column diameter. If I push it to the limit, let’s say I make my column height 48”/1.22m.

Now I’m just a bit confused by something. Is this the height to achieve azeo without packing? Or so I need to add packing too.
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Re: Column height vs. packing

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Yes you need packing
Probably some more reading too :)
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Re: Column height vs. packing

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Agree with the above by RC.....if you dont know that much then you need to read ? research more.
Lets be blunt ........you got a shit load of readin and learnin to do.
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Re: Column height vs. packing

Post by Renhoekk »

You will need packing and also a pre-condenser (dephlegmator). And you need enough height to let the packing do its job.

Each plate in a reflux column essentially carries out a mini-distillation. As the vapour moves up the column, it goes through a sequence of vaporising, re-condensing and vaporising again on the plates. And with each mini-distillation, more water drops down the column and a higher proof of ethanol goes up the column.

The packing replaces the function of the plates, in that it provides surface area for the rising vapor to go through cycles of condensing and vaporising.

The pre-condenser helps you control the rate of reflux by sending some or all of the vapor back down the column as liquid, to continue being separated/enriched.

Some packing types are more efficient than others - there's a few big discussion threads on here about that. Read up on packing, HETP (Height Equivalent Theoretical Plates), and dephlegmators for a start.
Last edited by Renhoekk on Sun Aug 28, 2022 3:11 am, edited 1 time in total.
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Re: Column height vs. packing

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Back when I joined the forum , this was were we learned the basics .Alas a lot of it is now outdated ,but the Still theory is still applicable . Especially all the stuff about packing and Theoretical Plates Equivalent Height.

https://web.archive.org/web/20171228074 ... ory/theory
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Re: Column height vs. packing

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Renhoekk wrote: Sun Aug 28, 2022 3:07 am You will need packing and also a pre-condenser (dephlegmator
Edit
Reason TUI last night " Typing Under the Influence"

A dephlegmator is a device arranged for the partial condensation of a multicomponent vapor stream. The vapor stream flows vertically upwards and the condensate (condensed vapor) runs back down under the influence of gravity. The vapor stream and condensate thus move countercurrently and are in direct contact with each other. In addition to heat transfer between the vapor stream and cooling medium, mass is transferred between the rising vapor and falling condensate. Vapor leaving the device has become concentrated in the more volatile components, while the condensate is richer in the less volatile components.
https://thermopedia.com/content/691/
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Re: Column height vs. packing

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Saltbush Bill wrote: Sun Aug 28, 2022 3:18 am
Renhoekk wrote: Sun Aug 28, 2022 3:07 am You will need packing and also a pre-condenser (dephlegmator
Bullshit ..do you know what a dephleglamator does ?.....a dephleglamator is not a reflux condenser
I used the term “pre-condenser” along with (dephlegmator), because when OP does some searching it will be helpful.

Even on this forum, a variety of terms are used to describe this particular piece of equipment.
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Re: Column height vs. packing

Post by Salt Must Flow »

rockymars, as the boiler heats up the wash/mash, vapor begins to rise up through the packing. Once the vapor reaches the top of the column contacting the reflux condenser it condenses and rains down continuously onto the packing. To allow the column to stabilize, your reflux condenser should be low enough so that no vapor can exit your vapor takeoff port. Now leave the column to run at 100% reflux for 10-20 min or so. This allows the most volatile lowest temp lightest vapors to accumulate at the top. Now begin to raise our reflux condenser slightly to allow 'some' vapor to slip past and into the vapor takeoff where it condenses inside your product condenser and collected in relatively small jars. You start collecting at a very slow takeoff rate at first to collect the foreshots. You can collect a little faster (raise the condenser) to collect the heads. Once you think you're into hearts you can collect even faster. If you have a digital thermometer with temp probe located in your vapor takeoff port, you can monitor the vapor temp in the 1/10th degree resolution. Throughout the entire spirit run, the temp will only change a few 1/10the degrees until you get to tails. Once you see the temp rise a few 1/10th degrees and stay, you know you're into tails, takeoff rate starts to slow all on its own and then you can shut down. Now if you take a sample out of the boiler, let it cool to 60F, you can test the % ABV and you'll see that is is less than 1% ABV. Of course testing this is not standard practice for every run, but seeing it for yourself at least once gives you confirmation that you're still did the job.

I personally have zero interest in CCVM design. I use a VM column. While stabilizing my column I can monitor the temp inside the vapor takeoff. I can see the temp rise and when the temp has stabilized. With a CCVM it appears that the reflux condenser blocks vapor from entering the vapor takeoff so IF you want to monitor the vapor temp at the top of the column you would have to shield the temp probe from the falling reflux otherwise you would be reading the temp of the reflux, not the vapor. You could just not monitor the vapor temp, rely on just waiting for a while and just run by your senses. Fiddling with raising/lowering the reflux condenser and wedging something to make it stay seems ghetto to me and may lack precise/repeatable control in comparison to a gate valve with a VM still. CCVM is fine, but is only a few steps away from being ideal.

Type of packing is very important. For an all stainless still, you could put copper bits inside the boiler and/or copper mesh at the base of your column. I put 3-4 rolls of copper mesh at the base of my column. I use properly sized Lava Rock to fill the rest of the column. I've tried all copper mesh, some mesh and the rest stainless scrubbers, ceramic rings and none of them worked anywhere near as well as Lava Rock with some copper mesh. With use copper mesh crinkles, loosens up in places and compacts in other places. Stainless scrubbers are extremely finicky with how loose/tight you pack it in the column, causes flooding and performance is often not repeatable. Ceramic packing just completely sucks, consistently causes flooding at low power input and has low % ABV output. Lava Rock (structured packing) is cheap, readily available, easy to sieve to proper size, is easy to use, is not finicky at all, allows you to run at higher power and higher takeoff rate while producing azeo reliably & repeatably. Lava Rock always produces azeo, you just need to figure out what your max power is and what your max takeoff rate is before your quality starts to drop. It performs damn near as good as SPP, but at a tiny fraction of the price.

I highly recommend a double wound copper coil as a reflux condenser.
Last edited by Salt Must Flow on Sun Aug 28, 2022 10:17 am, edited 1 time in total.
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Re: Column height vs. packing

Post by bluefish_dist »

Based on my reading you need a minimum of 15 plates for azeo. That means using scrubbies (4” hetp) you need 60” of packing. In reality I think you need more than that. It’s easy to get to 189 proof, harder to get to 190.5+. In the end, most don’t have the ability to measure the difference between 189 and 190+.
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Re: Column height vs. packing

Post by shadylane »

Saltbush Bill wrote: Sun Aug 28, 2022 3:18 am
Renhoekk wrote: Sun Aug 28, 2022 3:07 am You will need packing and also a pre-condenser (dephlegmator
Bullshit ..do you know what a dephleglamator does ?.....a dephleglamator is not a reflux condenser
Pull yer horns in Salty :lol:
A dephlegmator is a variable reflux condenser that's only used on CM stills.
It's controlled by varying the water flow through it with a needle valve.
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Re: Column height vs. packing

Post by shadylane »

Column height vs. packing vs take off rate.

Don't want to ferget about the take off rate when bragging about making azeo.
Lifes too short to be distilling one drop at a time. :lol:
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Re: Column height vs. packing

Post by Yummyrum »

Renhoekk wrote: Sun Aug 28, 2022 3:41 am
Saltbush Bill wrote: Sun Aug 28, 2022 3:18 am
Renhoekk wrote: Sun Aug 28, 2022 3:07 am You will need packing and also a pre-condenser (dephlegmator
Bullshit ..do you know what a dephleglamator does ?.....a dephleglamator is not a reflux condenser
I used the term “pre-condenser” along with (dephlegmator), because when OP does some searching it will be helpful.

Even on this forum, a variety of terms are used to describe this particular piece of equipment.
I think Partial Condenser would be a better word for a Deflagmator .

Pre-condensers are normally associated with product condensation . ..... probably not helpful to the OP at this point .
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Re: Column height vs. packing

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RC Al wrote: Sun Aug 28, 2022 2:17 am Yes you need packing
Probably some more reading too :)
I was just wondering if one could create enough theoretical plates through column height alone. Clearly not.

Back to reading some more…
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Re: Column height vs. packing

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Saltbush Bill wrote: Sun Aug 28, 2022 2:53 am Agree with the above by RC.....if you dont know that much then you need to read ? research more.
Lets be blunt ........you got a shit load of readin and learnin to do.
Not debating that, asking targeted questions help me home in on gaps in my knowledge. There are many. :!:
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Re: Column height vs. packing

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Renhoekk wrote: Sun Aug 28, 2022 3:07 am You will need packing and also a pre-condenser (dephlegmator). And you need enough height to let the packing do its job.
A pre-condenser even on a CCVM? I don’t think in my readings I’ve come across that before.
Renhoekk wrote: Sun Aug 28, 2022 3:07 am Each plate in a reflux column essentially carries out a mini-distillation. As the vapour moves up the column, it goes through a sequence of vaporising, re-condensing and vaporising again on the plates. And with each mini-distillation, more water drops down the column and a higher proof of ethanol goes up the column.

The packing replaces the function of the plates, in that it provides surface area for the rising vapor to go through cycles of condensing and vaporising.

The pre-condenser helps you control the rate of reflux by sending some or all of the vapor back down the column as liquid, to continue being separated/enriched.
This concept I get. The question was about whether one could achieve that without packing or physical plates.
Renhoekk wrote: Sun Aug 28, 2022 3:07 am Some packing types are more efficient than others - there's a few big discussion threads on here about that. Read up on packing, HETP (Height Equivalent Theoretical Plates), and dephlegmators for a start.
As far as packing goes, I was going to use copper scrubbies. When I do the HEPT calc for my preferred setup (2” with 1373W to achieve vapour rate of 20ft/sec, reflux at 2:1 and packing height of 1.2m), HEPT is 5” and I have 6.9 theoretical plates. Way short of the 13+ I need. So in this case a 1.2m+ column (which coincides with the 1:20 rule of thumb for height), I still fall short of azeo.

So it’s my understanding that I’ll have to either:
- increase design column & packing height (I’ll rerun the calc a few times more with higher values)
- use different, more “efficient” packing materials (I see lava rock is getting good press), however the HETP calculator does not have that as an option and I don’t know the characteristics (% fractional voids, surface area & critical surface tension)
- install physical plates
- install pre-condenser as per your suggestion.

Does that sound reasonable?
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Re: Column height vs. packing

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Yummyrum wrote: Sun Aug 28, 2022 3:10 am Back when I joined the forum , this was were we learned the basics .Alas a lot of it is now outdated ,but the Still theory is still applicable . Especially all the stuff about packing and Theoretical Plates Equivalent Height.

https://web.archive.org/web/20171228074 ... ory/theory
I might start here, thanks for the link yummy!
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Re: Column height vs. packing

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rockymars, I wouldn't be concerned that the online calculator doesn't have specs for Lava Rock. The only thing that truly matters is how it performs. It's performance has been proven, so technically it's the calculator that is out of date (no disrespect to the calculator). It sounds to me like you're questioning how tall of a column to make. Personally I would go with 5'. You could also use multiple 2" spools to make it as short or as tall as you like. I use multiple 3" spools because it is easier to break down, store and make the parts more manageable. My point is, you can always make it shorter or taller and there's no way you can fail. I'm just giving you info that I wish was given to me when I first started. It would have saved me a LOT of trial & error, headache, confusion, time and money.
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Re: Column height vs. packing

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Salt Must Flow wrote: Sun Aug 28, 2022 8:11 am rockymars, as the boiler heats up the wash/mash, vapor begins to rise up through the packing..
Without exception, these are some of my favourite posts. I love reading about how to manage a still run, regardless of the type. Thanks for posting SMF.
Salt Must Flow wrote: Sun Aug 28, 2022 8:11 am I personally have zero interest in CCVM design. I use a VM column.
Fair enough. I’ll try to find posts in which you describe your setup. I’m very curious.
Salt Must Flow wrote: Sun Aug 28, 2022 8:11 am Type of packing is very important. For an all stainless still, you could put copper bits inside the boiler and/or copper mesh at the base of your column. I put 3-4 rolls of copper mesh at the base of my column. I use properly sized Lava Rock to fill the rest of the column. I've tried all copper mesh, some mesh and the rest stainless scrubbers, ceramic rings and none of them worked anywhere near as well as Lava Rock with some copper mesh. With use copper mesh crinkles, loosens up in places and compacts in other places. Stainless scrubbers are extremely finicky with how loose/tight you pack it in the column, causes flooding and performance is often not repeatable. Ceramic packing just completely sucks, consistently causes flooding at low power input and has low % ABV output. Lava Rock (structured packing) is cheap, readily available, easy to sieve to proper size, is easy to use, is not finicky at all, allows you to run at higher power and higher takeoff rate while producing azeo reliably & repeatably. Lava Rock always produces azeo, you just need to figure out what your max power is and what your max takeoff rate is before your quality starts to drop. It performs damn near as good as SPP, but at a tiny fraction of the price.
Woah!!! Now I’m all eyes and ears.
1. Copper mesh… Does it matter which type I use (4-wire vs. 6-wire)? Denser is better right? And how do you pack them? I imagine you’d be rolling them into cylinders and pushing them into the column? The mesh seems to come in 10cm/4” wide rolls. So your cooper packing is about 12-16”?
2. Lava rock… I read somewhere the best size is 1/3 to 1/2” for a 2” column? I’d imagine something like chicken wire would sort out the chunks too big, but what do you use to get rid of the pieces too small? Do you have the characteristics handy which could make the HETP calculator work on lava rock?
Salt Must Flow wrote: Sun Aug 28, 2022 8:11 am I highly recommend a double wound copper coil as a reflux condenser.
What size tubing do you use? I’m really interested in how to wind a double-wound, it looks like it might be easy to throttle it?

Thanks again for your post, I loved reading it.
Last edited by rockymars on Sun Aug 28, 2022 3:43 pm, edited 2 times in total.
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Re: Column height vs. packing

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shadylane wrote: Sun Aug 28, 2022 10:27 am Column height vs. packing vs take off rate.

Don't want to ferget about the take off rate when bragging about making azeo.
Lifes too short to be distilling one drop at a time. :lol:
Very true!
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Re: Column height vs. packing

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Salt Must Flow wrote: Sun Aug 28, 2022 3:04 pm rockymars, I wouldn't be concerned that the online calculator doesn't have specs for Lava Rock. The only thing that truly matters is how it performs. It's performance has been proven, so technically it's the calculator that is out of date (no disrespect to the calculator). It sounds to me like you're questioning how tall of a column to make. Personally I would go with 5'. You could also use multiple 2" spools to make it as short or as tall as you like. I use multiple 3" spools because it is easier to break down, store and make the parts more manageable. My point is, you can always make it shorter or taller and there's no way you can fail. I'm just giving you info that I wish was given to me when I first started. It would have saved me a LOT of trial & error, headache, confusion, time and money.
That is exactly the point. Why repeat the mistakes of others? Learn from them, and stand on the shoulders that have gone before.

Point taken about the calculator. How much lava rock do you use/is the recommended packing height?
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Re: Column height vs. packing

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I have two different grades of copper mesh. One is more coarse and one is noticeably finer. I very much prefer to more coarse copper mesh. It doesn't appear to compress/compact anywhere near as much. The finer stuff doesn't allow for as good of vapor interaction throughout and it is evident by unrolling it and you can clearly see that it compacts too tight with use and doesn't tarnish inside the roller which is an indicator that there's no vapor interaction. The coarse mesh works great and tarnishes evenly throughout. I honestly don't what the proper classification is to the different grades of mesh, but the I'd go with whatever is more coarse.

I've measured my Lava Rock which I've been using in my 3" and it ranges anywhere from 1/4" to approx 1/3". I used a kitty litter scooper to sieve the Lava Rock. I collected and used what didn't fall through. I also kept the smaller bits, sieved that again using a metal wire strainer to discard the fines and tested the smaller size rock and it didn't work for me. It just caused my 3" column to flood. I suspect this smaller size might be ideal for a 2" column though. I bought my Lava Rock from Home Depot and it's advertised as 3/8" in size.
Lava Rock Sizes.jpg

For the 2" double wound coil, I used a 0.56" dia copper grounding rod I had in the garage. I don't recall what I used for the outer coil, maybe a PVC pipe. It was whatever I had in the garage. Most people here that make double wound coils do it in a continuous fashion. I wound my inner coil then my outer coil and connected the two using two 90 elbows. It just seemed easier for me to do it that way.
Dimroth Condenser 02.jpg
I made my 3" column 6' tall and it's fully packed with Lava Rock other than the 3-4 rolls of copper mesh at the base. I've tried mine with 5' of column and it worked just fine. I just use 6' because I have it and it can't hurt. For a 2" I can't imagine 5' would be overly excessive, but I've never ran a 2".
Last edited by Salt Must Flow on Mon Aug 29, 2022 7:33 am, edited 1 time in total.
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Re: Column height vs. packing

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shadylane wrote: Sun Aug 28, 2022 10:14 am
Pull yer horns in Salty :lol:
Eh…typical dogmatic Aussie Boomer. It was inevitable that Salty was either going to get into World War 2 history or home distilling :lol:
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Re: Column height vs. packing

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rockymars wrote: Sun Aug 28, 2022 2:08 pm
This concept I get. The question was about whether one could achieve that without packing or physical plates.
Well....if you had to ask if you could achieve azeo with a tall, empty column, then I don't think you understand the concept of reflux distillation at all.

Some people swear by lava rock to maximise column efficiency. I haven't tried it. I've tried SPP, which is claimed to have a HETP of about 3 inches. It works well, however for the cost I don't think it worked that much better than stainless Pall rings. Pot scrubbers also work well.
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Re: Column height vs. packing

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Renhoekk wrote: Mon Aug 29, 2022 1:00 pm
rockymars wrote: Sun Aug 28, 2022 2:08 pm
This concept I get. The question was about whether one could achieve that without packing or physical plates.
Well....if you had to ask if you could achieve azeo with a tall, empty column, then I don't think you understand the concept of reflux distillation at all.
I gave that a try awhile back just to see what happened.
A tall empty glass column didn't do nothing.
And the same column with a defleg was like driving with the brakes on. :lol:
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Re: Column height vs. packing

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Renhoekk wrote: Mon Aug 29, 2022 1:00 pm Well....if you had to ask if you could achieve azeo with a tall, empty column, then I don't think you understand the concept of reflux distillation at all.

Some people swear by lava rock to maximise column efficiency. I haven't tried it. I've tried SPP, which is claimed to have a HETP of about 3 inches. It works well, however for the cost I don't think it worked that much better than stainless Pall rings. Pot scrubbers also work well.
Fair enough Renhoekk :oops:
But in asking all these noob questions, you guys have been educating me a lot. Many of my questions (written or not) have been answered and I’m so grateful. Thanks for your patience!!! It looks like SPP is not worth the expense.

The idea of mesh with lava rock above is growing on me.
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Re: Column height vs. packing

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shadylane wrote: Mon Aug 29, 2022 1:25 pm I gave that a try awhile back just to see what happened.
A tall empty glass column didn't do nothing.
And the same column with a defleg was like driving with the brakes on. :lol:
Haha there you go. Somebody’s done the experiment already (as I would have done), and the result was a big resounding FAIL for an empty column. Sometimes it’s not about NOT believing the theory, it is about seeing for yourself. That’s how my mind works!
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Re: Column height vs. packing

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Salt Must Flow wrote: Sun Aug 28, 2022 4:01 pm I have two different grades of copper mesh. One is more coarse and one is noticeably finer. I very much prefer to more coarse copper mesh.
Thanks for the great information SMF, I’ll go with the coarsest grade I can find.
Salt Must Flow wrote: Sun Aug 28, 2022 4:01 pm I've measured my Lava Rock which I've been using in my 3" and it ranges anywhere from 1/4" to approx 1/3". I used a kitty litter scooper to sieve the Lava Rock. I collected and used what didn't fall through. I also kept the smaller bits, sieved that again using a metal wire strainer to discard the fines and tested the smaller size rock and it didn't work for me. It just caused my 3" column to flood. I suspect this smaller size might be ideal for a 2" column though.
Great info, once again! I can get the rock as about 40mm (1.5”) chunks from the local hardware giant. It is really cheap, but obviously a lot of crushing and sieving will be required. I might look for a finer grade of rock, and aim for about 1/4” size for my column.
Salt Must Flow wrote: Sun Aug 28, 2022 4:01 pm For the 2" double wound coil, I used a 0.56" dia copper grounding rod I had in the garage. I don't recall what I used for the outer coil, maybe a PVC pipe. It was whatever I had in the garage. Most people here that make double wound coils do it in a continuous fashion. I wound my inner coil then my outer coil and connected the two using two 90 elbows. It just seemed easier for me to do it that way.
Many ways to skin a cat! I can across a jig by QdanT, many seem to be using it and getting really nice looking coils. I might give that a go.
Salt Must Flow wrote: Sun Aug 28, 2022 4:01 pm I made my 3" column 6' tall and it's fully packed with Lava Rock other than the 3-4 rolls of copper mesh at the base. I've tried mine with 5' of column and it worked just fine. I just use 6' because I have it and it can't hurt. For a 2" I can't imagine 5' would be overly excessive, but I've never ran a 2".
My plan was to have a 5’ column. It will be modular (10” tri clamp sections), so it would be easy to experiment a bit with optimum height for my rig.

Not only do I like the way you pack your column, but I have been doing a heap of reading on VM columns and I like what I see and starting to sway in that direction too.
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Re: Column height vs. packing

Post by shadylane »

My 2 cents worth.
The scoria that looks like black glass with bubble holes, works better than the red soft stuff.
Get a big bag and sort through it. :ewink:
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Re: Column height vs. packing

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rockymars wrote: Mon Aug 29, 2022 2:30 pm
I have been doing a heap of reading on VM columns and I like what I see and starting to sway in that direction too.
Don't make up your mind too fast. :lol:
A lot depends on the cooling water source, if you have running water then I'd prefer a CM.
If you are limited to using recirculated water, then a LM, VM or CCVM would be a better option.
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Salt Must Flow
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Re: Column height vs. packing

Post by Salt Must Flow »

shadylane wrote: Mon Aug 29, 2022 3:57 pm
rockymars wrote: Mon Aug 29, 2022 2:30 pm
I have been doing a heap of reading on VM columns and I like what I see and starting to sway in that direction too.
Don't make up your mind too fast. :lol:
A lot depends on the cooling water source, if you have running water then I'd prefer a CM.
If you are limited to using recirculated water, then a LM, VM or CCVM would be a better option.
Curious, why would you prefer a CM with running water? Aren't CM stills more stably operated using a low pressure water pump in comparison to well water for instance? I know many use water pressure regulators too. I figured a CM would be better suited if one had to recirculate water. Well pumps kick on & off often which plays hell with providing consistent water flow & pressure. The easiest way I found to cool a dephlegmator for instance was to use a pond/aquarium pump for stable flow rate (though I never recirculated water before).

VM stills aren't affected by fluctuating water pressure/flow at all. It actually helps with a VM if the water temp is consistent. If the water starts to heat up (while recirculating), I imagine the flow might eventually need to increase over time with a VM or any other type of still. I put a thermowell in the output of my reflux condenser and I set a temp alarm with a digital thermometer so I can maintain the minimum flow rate to optimize water usage. The flow rate does go up & down, but never exceeds the set temp because I monitor it. Hell I even monitor the exiting water temp to my product condenser just so I know that it is operating in the range I determined.

I just look at it as if there's an issue, there's always a solution to fix it. VM is so darn simple to run, it just runs itself. I know I don't need to monitor the water temps, but it's so darn easy to do, not to mention convenient to see and to be alerted if it gets to hot for whatever reason. It happens.
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