Are short shotguns worth a shot?

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Benredbeard
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Are short shotguns worth a shot?

Post by Benredbeard »

Something like this dephlegmator as a product condenser just seems too easy: It's a not-quite-8" long shotgun with 6 tubes of 8mm or about 3/8" that I'm thinking would knock down most of what I would put out of a 2" column. That's about 46" of stainless which I'm thinking would be able to match a 3' copper Liebig.

https://www.aliexpress.com/item/Free-Sh ... 0fd07e49c6


Have I missed something critical here? Seems like few use a short-shotgun (dephleg style) as a product condenser, just wondering why?
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acfixer69
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Re: Are short shotguns worth a shot?

Post by acfixer69 »

Bad link there.
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Re: Are short shotguns worth a shot?

Post by Bushman »

As AC says the link is bad. I have a shot gun condenser that is way longer than it needs to be and I throw very little water at it to make it run so I can get by with a smaller one. The shotgun style dephlagmater definitely can be shorter than a Liebig. Not sure I have read anything on Liebig length for the design but I believe a member “Myles” built a Triple walled Liebig that was a lot shorter than the normal Liebig build.
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Re: Are short shotguns worth a shot?

Post by shadylane »

Here's a 4" shotgun and a dimroth dephleg
Both have the same knockdown power.
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Re: Are short shotguns worth a shot?

Post by cranky »

I personally don't have a lot of faith in a short product condenser. In theory it may work but a dephleg doesn't do the same job as a PC so it can usually be shorter and it's not as critical that it does knock down 100% of the vapor, where a PC has to absolutely knock down everything plus a little bit for safety. Factor in potential vapor speed and contact time and I think it can be far too easy to overwhelm a short PC regardless of how much theoretical area it has. Of course this is just my own opinion.
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Re: Are short shotguns worth a shot?

Post by still_stirrin »

Benredbeard wrote:...It's a not-quite-8" long shotgun with 6 tubes of 8mm, or about 3/8"...knock down most of what I would put out of a 2" column...about 46" of stainless which...would be able to match a 3' copper Liebig.
I doubt a shotgun (deflag) condenser 8” long with 6 tubes with 3/8” ID made of stainless would come close to equaling a 36” long copper Liebig with a 1/2” ID vapor tube. I’d bet you would be “passing gas” at just about any power setting.
Benredbeard wrote:...Have I missed something critical here? Seems like few use a short-shotgun (dephleg style) as a product condenser, just wondering why?
Shotgun condensers are a form of tube and shell heat exchangers which are specifically designed for process flow of fluids, either vapor or liquid. They are best designed when the coolant flow is optimized for efficiency, yet the tube bank is designed (length, tube count, tube diameter, and tube material) to transfer the heat from (or to) the coolant fluid (water in our case).

But in order to determine the tube & shell design, the process fluid (alcohol in our case) and the heat input to the boiler must be considered.

Also FYI, the conductive heat transfer coefficient for copper (400 W/m/*K) is 25 times greater than stainless steel (16 W/m/*K). So, a copper shotgun will be much, much more efficient at heat transfer (condensing power capable).

How much heat are you putting into the boiler? Gotta’ know the answer to this question before any design can progress.
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Re: Are short shotguns worth a shot?

Post by Benredbeard »

Thank goodness I asked. I'll be on propane so I'm afraid I don't know heat in watts. Liebigs are certainly welcome, I'm not married to a shotgun, but how does one step down from 2" to 3/4", step by step or in one whack?

My plan is for a CCVM 2" column in stainless.
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Re: Are short shotguns worth a shot?

Post by still_stirrin »

Benredbeard wrote:Thank goodness I asked. I'll be on propane so I'm afraid I don't know heat in watts. Liebigs are certainly welcome, I'm not married to a shotgun, but how does one step down from 2" to 3/4", step by step or in one whack?

My plan is for a CCVM 2" column in stainless.
So, you’ll use corrogated stainless steel tubing for the reflux condenser and vapor control “valve”. Look at Dad300’s design for the CCST reflux condenser size and function.

And for the product condenser, you could use CCST inside a 1” jacket as a Dimroth-like condenser. I believe Dad’s thread also shows that capability as well. I would suggest the product condenser be at least 36” long to be effective. Length of the product condenser also depends somewhat on the dwell time the vapor has inside the condenser, so you don’t want it too short.

You could build a shotgun for the product condenser, but I think the CCST will work just fine too.
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Re: Are short shotguns worth a shot?

Post by Benredbeard »

That's the plan for the RC; I hadn't considered corrugated for a product condenser. Does it need strict vertical orientation to prevent accumulation in the "ribs"/would it smear?
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Re: Are short shotguns worth a shot?

Post by still_stirrin »

Benredbeard wrote:That's the plan for the RC; I hadn't considered corrugated for a product condenser. Does it need strict vertical orientation to prevent accumulation in the "ribs"/would it smear?
The coolant flows through the CCST. The vapor condenses around the outside and the shell collects the drips to the outlet. It can work vertical or at an angle to vertical. I don’t think it would smear any worse than any other design.
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edit - here’s a quick link to the PC design using CCST: viewtopic.php?f=1&t=41579&hilit=control ... 0#p7105600
Last edited by still_stirrin on Tue Dec 11, 2018 8:07 pm, edited 1 time in total.
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Re: Are short shotguns worth a shot?

Post by Benredbeard »

Not quite visualizing it yet, Thank you I'll check that build!
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Re: Are short shotguns worth a shot?

Post by Yummyrum »

If the sole purpose of the PC is to make high proof nuetral in a CCVM then the requirements are not as stringent as if t was to be used as a stripper . Remember that most reflux stills will typically run with about 10:1 or high reflux ratio so the PC is only needing to knock down a 1/10 or less than the reflux condenser is .


However if the CCVM is to have the RC removed and be capped as a stripping still then you will need it to be as efficient as possible . Having said that , if you are removing the RC coil , then why not use it as the PC on the stripping run . . Have seen this done but can’t remember where .
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Re: Are short shotguns worth a shot?

Post by Benredbeard »

I'm having some difficulty finding or picturing how to seal corrugated where it penetrates into copper: does one just solder the snot out of it? I'm picturing a column for condensate, draining to product jars, and a cap that has both the in and out lines for the CSST... am I on the right track? This would make for a large (wide) condenser, how does one ensure adequate transit time?
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Re: Are short shotguns worth a shot?

Post by Benredbeard »

Picture > 1k words. Thanks!
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Re: Are short shotguns worth a shot?

Post by OtisT »

I chose not to use a shotgun because it was a hell of a lot of work to make and expensive to buy. I still wanted a compact profile so settled on a copper coil dimroth product condenser what seemed simple and very compact. A single 1.5” OD coil 10” long, 26 winds of 1/4”soft copper in a 2” column will just knock down 5500w.

I have been very happy with the performance and compact profile, and use this same PC on my 2” and 3” VMs. I am making a 3” chambered dimroth to handle more power, a double coil of 1/4”copper tubing, each with independent inputs and outputs for double the coolant flow over my existing single coil dimroth PC.

If you want to see the dimroth, it it’s in the thread showing my potnthumper. viewtopic.php?f=16&t=70230#p7517994

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Re: Are short shotguns worth a shot?

Post by Benredbeard »

OtisT wrote:
If you want to see the dimroth, it it’s in the thread showing my potnthumper. viewtopic.php?f=16&t=70230#p7517994

Otis
Yep, that's just stone cold gorgeous. :). Nice build Otis!

Did you make/use a jig or anything beyond packing for making that coil?
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Re: Are short shotguns worth a shot?

Post by cranky »

On my pot still I go from 1.5" to 3/4" to 1/2" into a 36" liebig It works fine and can handle everything my 5500W burner can throw at it. In my reflux setup I use a 24" 3 tube shotgun. It's possible to overwhelm my shotgun if I really push it hard. I also have a double dimroth made of 2 lengths of CSST and a total cooling length of 14". The liebig was by far the easiest thing to build but the double dimroth is the coolest looking.

On Dad's setup with the CSST inside 1' he came in from the bottom so he didn't have to seal the tube, just bent them upward.
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Re: Are short shotguns worth a shot?

Post by Benredbeard »

cranky wrote:On my pot still I go from 1.5" to 3/4" to 1/2" into a 36" liebig It works fine...

I also have a double dimroth made of 2 lengths of CSST and a total cooling length of 14". The liebig was by far the easiest thing to build but the double dimroth is the coolest looking.

On Dad's setup with the CSST inside 1' he came in from the bottom so he didn't have to seal the tube, just bent them upward.
I did finally grog on to the bottom bend-up bit with some hand-holding, sheesh [FACE WITH TEARS OF JOY].

Cranky do you have any pics of that corrugated/dimroth?
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Re: Are short shotguns worth a shot?

Post by Twisted Brick »

cranky wrote:I personally don't have a lot of faith in a short product condenser. In theory it may work but a dephleg doesn't do the same job as a PC so it can usually be shorter and it's not as critical that it does knock down 100% of the vapor, where a PC has to absolutely knock down everything plus a little bit for safety. Factor in potential vapor speed and contact time and I think it can be far too easy to overwhelm a short PC regardless of how much theoretical area it has. Of course this is just my own opinion.
+1

My 4 x 1/2" shotgun is 21" and during a full-power strip only the first 3" of the vapor-side shell remains hot. This led me to believe I overbuilt the condenser in length. However - during a lengthy (9 gal of low wines) spirit run, the water in my 35gal recirc barrel increases temp to about 120F, and at the end of the run the entire shell is hot to the touch. The heads come out around ~73F and tails around 90F, but no vapor ever, even with a small coolant supply rate.

I've gotten over the idea of a shorter shotgun because I like the insurance. I would still like to get a radiator or some such to cool the exit water from the condenser to the reservoir to ensure a cooler distillate temp, tho.
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Re: Are short shotguns worth a shot?

Post by StillerBoy »

Does a short shotgun PC condenser work.. sure it does..

The picture is my shotgun condenser, 1.5" x 14" overall, with 5 - 3/8" tubes, with 12" cooling area with 4 baffles.. it knocks down what ever my 3" flute or in pot mode can give using a 5500 watt element..

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Re: Are short shotguns worth a shot?

Post by OtisT »

Benredbeard wrote:
OtisT wrote:
If you want to see the dimroth, it it’s in the thread showing my potnthumper. viewtopic.php?f=16&t=70230#p7517994

Otis
Yep, that's just stone cold gorgeous. :). Nice build Otis!

Did you make/use a jig or anything beyond packing for making that coil?
Thanks for the kind words.

The first few coils I made by hand looked just as nice, but I did end up making a simple coil winding machine because I have been selling some of these. That machine looks like Frankenstein made it, but it makes the winding quick and easy.

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Re: Are short shotguns worth a shot?

Post by cranky »

Benredbeard wrote:Cranky do you have any pics of that corrugated/dimroth?
It's hard to get a good picture of it but here is what I have
double dimroth #1 - C.JPG
I try not to publicize my reflux stuff too much because it's not really approved materials and I haven't posted anything there for a long time, but my build thread is here
viewtopic.php?f=50&t=55608&start=390

I run a single Dimroth RC on the flute as well the PC is just 2 of them run in series.
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Re: Are short shotguns worth a shot?

Post by Benredbeard »

POW! Thank you, man I bet that knocks 'em down all day long! Cool idea condensing inside a sight glass. In series 'explains everything.
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Re: Are short shotguns worth a shot?

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Benredbeard wrote:POW! Thank you, man I bet that knocks 'em down all day long! Cool idea condensing inside a sight glass. In series 'explains everything.
Thank you. :D
Personally I like visistills even though you have to be careful running them. They do show the Dimroths quite well, as well as what's actually going on inside. The problem with condensing inside glass is you have to be concerned with shock cooling fracturing the glass so you can't get everything warmed up before you turn on the water. If I get everything hot and then turn on the water it will cost me another dollar for a new "sight glass" :roll:
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Re: Are short shotguns worth a shot?

Post by Benredbeard »

cranky wrote: If I get everything hot and then turn on the water it will cost me another dollar for a new "sight glass" :roll:
Exciting :). If borosilicate were cheaper, I expect we'd see all manner of sexy columns!
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Re: Are short shotguns worth a shot?

Post by cranky »

Benredbeard wrote:
cranky wrote: If I get everything hot and then turn on the water it will cost me another dollar for a new "sight glass" :roll:
Exciting :). If borosilicate were cheaper, I expect we'd see all manner of sexy columns!
It's actually not all that expensive, I think the larger diameters are actually cheaper than the same size copper but there are other expenses involved in holding pieces together and sealing so it's a little harder to deal with than copper or stainless steel.
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