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Old 02-02-2010, 02:54 AM   #1
Bigscience
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Default Separate HERMS HEX Build

After many years with a HLT heat exchanger, I want to build a separate, small volume heat exchanger. I have a 5 gal sanke I was thinking could be cut down to about half the size and then weld a coil in through the sides for ease of draining. For flow rate, I wanted to use 1/2" stainless tube, about 25' of it for good exchange. The diameter of the keg is 9.25" so I was thinking a 7" diameter coil would leave enough room for couplers/welding.



Here are the questions:

Can you bend 1/2" tube in a 7" diameter coil? I'm not assuming I can do this by hand but could a machine shop do it? I have a nice CFC that's in a 6.25" coil but that has 3/8 tube inside it so maybe that's why it didn't crush.

I emailed nybrewsupply and they said they could do it with 3/8" but didn't think it would work with 1/2". I really don't want to do 3/8" for flow reasons. Does anyone use a 3/8" coil and if so, how does it work out?

For the coupling through the keg wall, I was thinking about doing something like below BUT since it will be so tight, I was thinking about welding the elbows to the tube and then welding the elbow to the keg wall. Any other ideas on how to pull this off?



Thanks in advance for the help.


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Old 02-02-2010, 03:09 AM   #2
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I have 1/2" SS coil in my rig, that stuff is TOUGH!...

Personally, I dont think you are going to be recirculating your mash fast enough for 3/8" tubing to make any difference, do you? 25' is plenty for the exchange, but I think your flow will be less than 1gal/min anyway which 3/8" can accomodate easily.

I personally wouldnt WELD the coil in. I used triclamps to mount mine in the kettle...






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Old 02-02-2010, 03:38 AM   #3
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Since the diameter of the keg is only 9.25", there is really no room for triclamps or compression fittings to mess with. I'm not talking about a 1/2 barrel keg but a 5 gal sanke, cut in half to reduce the volume.
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Old 02-02-2010, 03:40 AM   #4
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Well, that is all I have to offer... that would be a tough weld job.
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Old 02-02-2010, 03:51 AM   #5
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I don't think you could coil it that small w/o collapsing. I wanted to do the same thing. My Uncle owns a shop that rolls and bends metal. He said that trying to bend stainless tighter than a 10" coil would be nearly impossible. I was using the stainless coil material from McMaster. I forget the wall thickness, Just what he told me.
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Old 02-02-2010, 03:53 AM   #6
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Quote:
Originally Posted by Dog House Brew View Post
I don't think you could coil it that small w/o collapsing. I wanted to do the same thing. My Uncle owns a shop that rolls and bends metal. He said that trying to bend stainless tighter than a 10" coil would be nearly impossible. I was using the stainless coil material from McMaster. I forget the wall thickness, Just what he told me.
FWIW, my 1/2" OD SS tubing is deformed from the coiling process. When I cut it and added the compression fittings, I had to re-round the ends, the coiling made the tubing oval in shape.... it is a 10" DIA BTW
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Old 02-02-2010, 03:56 AM   #7
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Quote:
Originally Posted by The Pol View Post
Well, that is all I have to offer... that would be a tough weld job.
The idea I was tossing around was to weld some 90s on the ends of the coil (it would look like yours is), drill 2 holes through the sides, pull the 90s through and then weld them on the outside. If it works out better, I could cut off the top and the bottom (minus some length) to do the welding and then weld them back on at the end.

If it wasn't already obvious, I really don't know much about metalworking and what's possible or not.
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Old 02-09-2010, 05:14 AM   #8
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Default Element Coupler Straight vs NPT

I found a shop that will coil the ss tube for me and maybe do the welding as well. I need to buy the coupler for the element now. If I remember, heater elements are straight thread while NPT is tapered. What do other people use? I want to keep everything welded and not bulkheads.

Will this work?

http://www.buyfittingsonline.com/Fittings/item6494.htm
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Old 02-09-2010, 06:20 AM   #9
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Don't weld the SS coil to the bulkhead. You'll want to be able to remove the coil for deep cleaning, modification, etc... at a later date. I've taken mine out a few times and modified it to optimize length.

Take it to the welder and have him weld the tube to a matching tri clamp ferrule. Then have him roll that SS as tight as he can and use tri's (even 1/2" sabco tri's) to weld into the bulkhead. You should have enough room to make it fit if the welder can get the coil into a 6-7" roll.
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Old 02-09-2010, 07:26 AM   #10
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Quote:
Originally Posted by Bigscience View Post
I found a shop that will coil the ss tube for me and maybe do the welding as well. I need to buy the coupler for the element now. If I remember, heater elements are straight thread while NPT is tapered. What do other people use? I want to keep everything welded and not bulkheads.

Will this work?

http://www.buyfittingsonline.com/Fittings/item6494.htm
Yep, that half coupling will work just fine. I bought one last week for my new HLT. I am considering replacing the black rubber seal that came with the element with a high-temp silicone o-ring though.



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