DIY convoluted copper

[Vesku]

I've been destroying a lot of copper tube, but finally got my tool working:

Gutted:

CFC:

Double copper test (ugly):

Test plot, 3.5L/min flow for hot water, 10L/min for the cool (12C):

I used 15mm copper for the copper/pvc-CFC and some imperial about the same size for the double copper CFC.

The tool is just a hole in 2X4 and adjustable bearing. Annealed copper works better, but "hard" copper can be used too. It needs re-annealing after the grooves are made to be able to make the coil.

For the next one (a shorter one for my CFC-HERMS), I'll try to "twist" the outer copper as well (except the bends). And it will have a shape of something like this:

 

[Coldies]

Looks awesome.

 

[thelorax121]

I would love to see some pics of the jig you used on that. It looks great!

 

[Dan]

I would love to see some pics of the jig you used on that. It looks great!

I second that!

Looks great!

 

[Vesku]

I made this for the double copper:

Here's some of the "twisting tools":

 

[jsguitar]

Looks awesome!

Now, please forgive some ignorant questions. I can't really see the twisting tools very well. It sounds like you made grooves in the tube and then twisted? Can you go into more detail on the process? Thanks!

 

[Vesku]

I want to you guys to think too Everything is made so easy nowadays with the google and all

It's basically a thread die, a very dull one. Drill a hole that has two angles. One angle is for the angle that the bearing is against the copper and other for how fast it moves when you roll it on the tube. I'll took a video clip next time I'm doing something (may take some time as I'm totally out of money. I've to wait until the scrapyard has some copper...)

I don't know how the real tools work, but I would guess the process is the same. I don't think that the tube is actually twisted at all, just "grooved".

 

[jsguitar]

Thanks, that clears up alot.

I'm not very tool savy and wouldn't have known to look up thread die, but when I first saw it I thought it looked a bit like it was gone over with a dull pipe cutter on a diagonal somehow.

It's really clever and a very professional looking result.

I'm sure everyone would appreciate a video demonstration.

Nice work!

 

[Dan]

+1 one to JsGuitar.

Your craftmanship and ingenuity are amazing. Looking forward to more!

Dan

 

[Barneey]

I`ve just notice this thread and was interested in having a go at producing a homemade convoluted tube, just wondered if anyone else has been sucessful in copying the idea.

More experiments to follow

 

[Vesku]

Here's a video:

[ame="http://youtu.be/_So8bqPPmio"]http://youtu.be/_So8bqPPmio[/ame]

 

[Dan]

You make it all look easy! Great video. Thanks for sharing. I really had no clue what the method was when you posted the pics of your equipment. What angle is the hole in the board cut?

 

[jsguitar]

+1, You're clearly an expert at this now! I also couldn't imagine how you were doing it before, so this helps.

I'm sure you don't want to take your tool apart for pictures, but if you're ever up for it I'd like to see what the thread die looks like that you're using.

I've enjoyed your recent contributions, thanks!

 

[Vesku]

There's a skateboard bearing that is "leaning" against the tube. I just screw it against the tube with the threaded rod with handle on it's end. Pretty simple thing really.

I made a few test holes to get the angles right. I 1st just had a knife blade against the tube to mark how fast it moves forward when rolled. I used a router to make the "machining" of the tool. No idea what the angles are though. Easy&cheap to test, if the material for the tool frame is wood. And if a proper tool is machined, it should be easy enough to figure out the angles when doing the CAD drawing.

 

[freeokw]

Very clever! Thanks for the video.
Cheers!

 

[Vesku]

I like plots too I found this one that I though I already deleted. It shows better how the CFC with the outer PVC hose performed:

The in going water was about 78C. 1st I ran it with with free flow 2.5L/min. Without any cooling water the temperature (blue line) drops a couple of degrees.
Next I opened the cooling water tap (12C). The output drop fast to about 16C.
Then I used pump to force the to be cooled water trough the CFC. The flow was about 11.5L/min and out coming water 34C.
I'm looking forward to see how fast I can cool my next patch as I'm using the new whirlpool kettle and this cooler. It should be pretty darn fast cooling for my 5 gal patch. 5 minutes?!!?

The blue line is output. The red one is the input. Others are just there to make the plot harder to read.

 

[jsguitar]

Others are just there to make the plot harder to read.

I like your teaching style Vesku

Seriously, when you design a space capsule brewery, I want to know about it!

 

[Dan]

I'm lost.. never been good at reading graphs.

 

[Vesku]

I like your teaching style Vesku

Seriously, when you design a space capsule brewery, I want to know about it!

I've a new idea for instant step mashes ( > 40F/min ), but that may need zero gravity to work ... so maybe the space rocket is the next step

 

[Barneey]

Great video mate.

Cheers

 

[OMJ]

have you tested at all the chilling time of convoluted copper vs straight copper?

 

[Vesku]

Not with same diameter (15mm) tube. I was able to find note's of ½" CFC with 19mm PVC. This was about 2 times longer than the convoluted. My notes say:
"Cooling efficiency when using cooling water at 12C, with approx. 7.5L/min flow:
- water in 82.5C
- water out 20.9C
- gravity fed free flow 3.5L/min"

 

[Carlscan26]

I like plots too I found this one that I though I already deleted. It shows better how the CFC with the outer PVC hose performed:

The in going water was about 78C. 1st I ran it with with free flow 2.5L/min. Without any cooling water the temperature (blue line) drops a couple of degrees.
Next I opened the cooling water tap (12C). The output drop fast to about 16C.
Then I used pump to force the to be cooled water trough the CFC. The flow was about 11.5L/min and out coming water 34C.
I'm looking forward to see how fast I can cool my next patch as I'm using the new whirlpool kettle and this cooler. It should be pretty darn fast cooling for my 5 gal patch. 5 minutes?!!?

The blue line is output. The red one is the input. Others are just there to make the plot harder to read.

Vesku, I'm having trouble reading this graph...at what time did it drop a couple of degrees and then the faster drop? I don't really see those unless the temp drop,is when the line goes up? Sorry if I'm being dense here...

 

[fafrd]

Here's a video:

http://youtu.be/_So8bqPPmio

Vesku,

the video seems to be no longer available. I may be interested to give this a try and would appreciate a chance to see the video if possible. The tool description is suggestive but I do not yet have a clear idea how to make one. Any kind of a quick sketch to help clarify would be greatly appreciated.

Also, can you commend on the wall thickness of the copper tubing you convoluted?

And lastly, do you think there is any hope of this technique working on 0.02" thin-wall stainless tubing?

thanks,

-fafrd

 

[TerraNova]

I am also hoping to do something like this but cant seem to make my jig work based on the written description. Any ideas on how to make this work?

Anyone?

 

[fafrd]

I am also hoping to do something like this but cant seem to make my jig work based on the written description. Any ideas on how to make this work?

Anyone?

Seconding this request. Also interested to know if those who have done this think it would work on thin-wall (0.02") stainless tubing...

-fafrd

 

[cwi]

Convoluted tubing is only needed if you aren't flowing fast enough to create turbulent flow . If you aren't creating turbulent flow, it's because your tubing is larger than needed for the flow rate (Reynolds number, or some crap like that). Going down a size can sometimes give superior performance to a larger round tube, and longer smaller tubing will accomplish the same thing as shorter larger convoluted tubing. When just looking at price, more of the smaller tubing is usually a cheaper solution, even if you convolute the tubing yourself.

 

[TerraNova]

So just to be clear, you are saying that using a smaller, longer inner tube can create enough turbulence? Or are you saying to size down the outer tubing of the CFC to create turbulence of the coolant?

Sorry to be so thick headed I just want to understand the concept you are describing so I can build the best possible apparatus.

Thanks in advance.

 

[cwi]

So just to be clear, you are saying that using a smaller, longer inner tube can create enough turbulence? Or are you saying to size down the outer tubing of the CFC to create turbulence of the coolant?

Sorry to be so thick headed I just want to understand the concept you are describing so I can build the best possible apparatus.

Thanks in advance.

Nothing wrong with asking, as this is fairly counter-intuitive, like many things.

A benefit of convolutions is to provide turbulence/mixing vs. laminar flow (it also provides minor benefit of a bit higher surface area/cross section ratio- circular tube is perfectly minimized in this regard). The turbulence of both the inner and outer liquid is important. The outer liquid, in this case, is not (usually) constrained to some maximum flow, so getting turbulence there is not (usually) an issue. The inner liquid may be flow constrained by the desired output temp (for single pass cooling). If this flow is insufficient to create turbulence, a smaller diameter tube that provides turbulence at that flow can perform better than the larger non-turbulent flow tube. It may even work at the same length, but the length may also need to be increased to meet the desired temp. That's the theory anyway. There are too many scenarios to describe when larger non-turb beats smaller turb, or vice-versa. I am just giving the rationale behind convoluted tubing, and the alternatives.

The amount of flow to get turbulence isn't that high, especially for circular spirals. I don't have any guidance to provide regarding optimal tubing size, but there have been threads on in it. Or, if you are good at math, there are the Reynolds equations to make some theoretical calcs.

The whole CFC/PC fascination is kind of lost on me, though, especially when recircing to the kettle and/or prechilling is required. I always saw them as only well suited to cases where tap water was cold enough to provide single pass cooling to ferm temps, and you either had a conical, or didn't care about all the cold break getting in your fermenter. Personally, I am an IC believer. Ease of use and simplicity trumps optimized performance in my world.

 

[TerraNova]

Thanks for the info. I am gathering all the data I can before building mine. I was thinking of going with a smaller inner tube anyway as EVERYBODY I have spoken to seems to throttle back on the wort going through theirs which a) reduces turbulence and b) reduces surface contact with the inner tubbing.

I agree with not quite getting the benefit of recirculating if a single pass would make you reach pitching temp. It means more things touching your wort as it is cooled which risks infection. It also means you still have to transfer your chilled wort into your fermenting vessel after it is cooled instead of transferring it while cooling it. And since I do a secondary fermentation, I would leave all the cold break behind with the yeast/trub at that point. While cold break in the fermentation tank doesn't hurt the beer, some say it actually helps fermentation (I can't back that claim up though).

The CFC advantage to me is that I switch batch sizes often. I have tried using a smaller IC that was designed for 5 gallon batches on a 10 gallon batch which barely worked (took forever). And when I tried a bigger IC designed for 10 gallon batches about 35-40% of the coils sat above the top of wort in a 5 gallon batch...which didn't hurt the cooling but since I couldn't submerge all of it during the boil it opened it up to infection as an unboiled item was in my wort. Yes, you can sanitize it before placing it in the wort (or try spooning boiling wort over the exposed coils, I guess), which is an extra step (your are sanitizing you transfer lines with an IC anyway, just like you would sanitize a CFC)

A CFC seems to be the right solution for doing any batch size and seems easiest to protect against infections.

As far as pre-chillers go, if your tap water is warm you really have to use it one with either style of apparatus to get down to the temps you may want.