Separate HERMS HEX Build

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Bigscience

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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.

4288821237_9a42d2b3e2_o.jpg


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?

14531d1265072816-semi-automatic-herms-system-work-progress-5.jpg


Thanks in advance for the help.
 
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...

P1030639.JPG


P1030671.JPG
 
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.
 
Well, that is all I have to offer... that would be a tough weld job.
 
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.
 
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
 
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.
 
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.
 
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.

ef07864f46c1950ee8238b41d388762c.jpg
 
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.

While I think this is a great solution for a 1/2 barrel keg, since the triclamps will be between the coil and the wall, how am I supposed to get even 1 hand in there to open and close it? The diameter of the keg is only 9.25" (think cornie). If I could pull it off with the top one, there's no way to reach the bottom one.

The idea of this chamber was to have as small a volume of water as possible so the temps could be changed quickly. This however creates some challenges however.



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.


Thanks! Time for another order of shiny goodness.
 
Why bother going through the sides at all, just run them straight up and out the top?

I want the HEX to be mounted to the stand and totally CIP (clean in place). While I could flush a coil that comes in and out the top, there'd be residual fluid left in it. I'd need to remove and invert to drain. Yet another thing to break down.
 
its pretty much a full corny, thats 25' 1/2 copper, 1500 watt element. i really like it and the temp doesnt fluctuate, i can keep a steady 152. i only fill to the top of the coiled part.
i like this design but personally i would rather have a temp controlled lauter tun and just have 3 tanks instead of 4. other than that i love having another fun peice of equipment

hers an older shot of my stand

rig1.jpg

rig4.jpg
 
make note though, to save time i pre heat my water in my boil kettle to 152, also recently i discovered that my efficiency sucks and that is because i did not take in consideration of the temps in my mash tun just the wort coming out of the exchange. i may need to bump the temp up.
 
Would two 1/4" coils work? It seems they would be easier to bend to your radius. You could use an adapter to go from (1) 1/2" to (2) 1/4" on both the inlet and outlet. More surface area for better heat exchange too... right? :confused:
 
I want the HEX to be mounted to the stand and totally CIP (clean in place). While I could flush a coil that comes in and out the top, there'd be residual fluid left in it. I'd need to remove and invert to drain. Yet another thing to break down.

Makes perfect sense! Thanks!
 
so i thought i would say on my first design i had the lid still intact and i was able to get the coil in.. but be warned it was hard as hell. i did this so i could close it up and it would not lose alot of heat. i took the top off because i couldn't tighten the compression fitting
 
No experience here. Just inspired to pose a question after viewing kickflip's cool pics. Would you have room for the tri-clover fitting in the bottom of the keg, between the side-wall and element? I'm assuming that accessing the bottom fitting is the tight spot.
 
I don't think there will really be much room to do much at all that requires any kind of dexterity. In fact, to do the welding, the though was to cut off the top and bottom, remove some of the middle to make the height/volume smaller and then weld the coil in. This would allow accessing the inside and out. Then, the top and bottoms would be welded back on.

One idea I saw that I didn't think of was a drain to remove the chamber fluid. I'll have to try to incorporate that into the design.
 
This is an issue that I have thought about a lot. Why are you wanting to use a small heat exchanger as opposed to the coil in you HLT? I currently am using a small exchanger and went that way in the hopes of ramping temps quickly. I've found that even a small exchanger doesn't really allow you to step mash, so is there another reason you want to do this?

I'm actually in the process of going the other way, incorporating my coil in a HLT and getting rid of the small exchanger. One reason was that it was poorly built in the first place and wanted to put something in that is better constructed.
 
This is an issue that I have thought about a lot. Why are you wanting to use a small heat exchanger as opposed to the coil in you HLT? I currently am using a small exchanger and went that way in the hopes of ramping temps quickly. I've found that even a small exchanger doesn't really allow you to step mash, so is there another reason you want to do this?

I'm actually in the process of going the other way, incorporating my coil in a HLT and getting rid of the small exchanger. One reason was that it was poorly built in the first place and wanted to put something in that is better constructed.

I have a HLT HEX right now that is propane fired. I want the control of electric and the ability to be able to change the liquid temp faster, thus the smaller volume. Why can you not step mash with your setup? Do you stir in the chamber?

As long as the flow rate is the same and the exit temp is maxed, how is 25' of coil in a smaller container not as good as in a larger container?
 
I am a newbe, but have read a lot about the idea of step mashing with a HERMS. It appears that you really can't get much more than 1 degree a minute raise, so if you are stepping up from 130 to 152, potentially a bunch of the conversion has happened before you ever get there.

I was getting rid of my small HEX so that I could use a larger amount of water and double it as my sparge water? Just seemed a little more efficient / simple since I have given up on the idea of "Step Mashing" on a HERMS.

I haven't cut into the HLT yet, and am running my ideas by everyone to see if I've missed something.

Note: I do use the HERMS to ramp up to 168 for Mash out
 
I am a newbe, but have read a lot about the idea of step mashing with a HERMS. It appears that you really can't get much more than 1 degree a minute raise, so if you are stepping up from 130 to 152, potentially a bunch of the conversion has happened before you ever get there.

I was getting rid of my small HEX so that I could use a larger amount of water and double it as my sparge water? Just seemed a little more efficient / simple since I have given up on the idea of "Step Mashing" on a HERMS.

I haven't cut into the HLT yet, and am running my ideas by everyone to see if I've missed something.

Note: I do use the HERMS to ramp up to 168 for Mash out

Off Topic:

I do step mashes with my current setup just fine. If you don't use a HERMS/RIMS for step mashing, are you just using it to maintain temp? At the risk of starting up the HERMS vs. RIMS or any enzyme denaturation wars again, you have to have your setpoint higher than your target to get the faster step times and then tune it back once you get close.

Return to topic:


So are you getting rid of your small chamber then?
 
I think I am going to get rid of the small chamber. I may try turning off the pump, jacking up the temp, and then start recirculating.

Like mentioned before, I don't want to get into the denaturing discussion either. Just trying to identify the pros and cons of big HEX vs small HEX.
 
I think I am going to get rid of the small chamber. I may try turning off the pump, jacking up the temp, and then start recirculating.

Like mentioned before, I don't want to get into the denaturing discussion either. Just trying to identify the pros and cons of big HEX vs small HEX.

The pros of the big would be a bigger thermal mass that would take longer to change (drop) and one less chamber to have since you could use your HLT. The pros of the small would be that you COULD change the temp faster to raise the chamber temp to higher more quickly.

Think about if you had a big or a small chamber set to 122 and you wanted to go to 155. It would take longer in a larger tank.

Now, while you are recirculating, the coil would be cooling the chamber down. The larger tank would have more heat to give up. Since you are providing more heat via an element or burner, this isn't a big deal. This is why I like the idea of a smaller chamber for the response time.

There is a really good site out there where somebody breaks it down better but I can't seem to find it right now. I'd say if you don't like the small chamber, you probably won't like the large either.
 
So out of curriosity, why are you doing a coil of ss? I mean if your going to weld the tubing in place why not just do verticle tubes with u joints linking them in a chain?
 
So i wish i went with something smaller for example a paint can size or a little larger.. its not to hard for my to drop the temp. i have a small 1/4 ball valve on the bottom for the drain, i just drain about a half gallon out and dump cold water in... i can drop about 10 degrees.. did it today with no problem.
 
So out of curiosity, why are you doing a coil of ss? I mean if your going to weld the tubing in place why not just do vertical tubes with u joints linking them in a chain?

Copper would work and that's what some people use. I have it in my HLT now. I'm using ss for the durability, chemical resistance and cool factor. I think the ss makes it look a little more professional and I wouldn't really want to weld the copper to the ss keg anyway.

I'm using a coil in and out the sides for drainability and to not make a bubble trap. If you believe in HSA or not, why not try to avoid it. As for the linked up sticks with street elbows, it would trap more liquid and I believe somebody here tried it for a chiller in PVC and reported back it didn't work well at all.
 
Copper would work and that's what some people use. I have it in my HLT now. I'm using ss for the durability, chemical resistance and cool factor. I think the ss makes it look a little more professional and I wouldn't really want to weld the copper to the ss keg anyway.

I'm using a coil in and out the sides for drainability and to not make a bubble trap. If you believe in HSA or not, why not try to avoid it. As for the linked up sticks with street elbows, it would trap more liquid and I believe somebody here tried it for a chiller in PVC and reported back it didn't work well at all.

I dont think you can weld SS to copper anyways. You could always go with a shell and tube design too.
 
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.

Did you ever end up replacing the black rubber seal that came with the element with a high-temp silicone o-ring? I'm looking to do the same thing but the ones I've seen are round and usually intended for the weldless locknuts. Let me know if you find one that works.

As for an update, I received all my components and now all I need to do is get together with the machine shop to start the build.
 
Did you ever end up replacing the black rubber seal that came with the element with a high-temp silicone o-ring? I'm looking to do the same thing but the ones I've seen are round and usually intended for the weldless locknuts. Let me know if you find one that works.

As for an update, I received all my components and now all I need to do is get together with the machine shop to start the build.

I'm placing an order with McMaster in the next couple of days for a bunch of little stuff I need to finish off my build. I'll let you know if I succeed :).
 
Yes you can weld SS to Copper. You want to use the SS filler for the job.

I asked that question over 3 years ago on the miller welds forum and a NASA looking photo was posted with copper tube with a copper end cap.

Check this below Miller thread of a person looking for a Tig welder, check "egbob" reply number 5 with his 3 photos you'll understand his work as well why I like this Miller forum.

http://www.millerwelds.com/resources/communities/mboard/showthread.php?t=20819
 
After many weeks of anticipation, I got the completed heat exchanger back from the welder. I think it is one of the coolest things I’ve seen.

Some things that ended up different than my design are: Coil Diameter is smaller and therefore takes up more height in the chamber and make a taller chamber necessary, RTD port is on the side to not be too close to the element.

I hope to do some leak and maybe some ramp testing on it this weekend. I probably won’t brew with it until I can get the set points and RTD positioning figured out though.

For all non-believers that said it couldn’t be built, here are some shiny picts.

4728968817_2ce0a3ee4c_b.jpg


4729615014_cdc1e5554d_b.jpg


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Here you can see the tip of the RDT sticking out:
4729624192_17779a4894_b.jpg


Here is the lid:
4729616142_d0f761cefa_b.jpg


Element:
4729629954_a6d381b00b_b.jpg


RTD Port:
4729624810_c3f14836bf_b.jpg


Lower coil enry point:
4729625328_62dc18a587_b.jpg


So my question now is, do I configure the out flow vertical like this:
4728980449_0204bef11a_b.jpg


Or horizontal like this:
4729626820_2c548a291a_b.jpg


I think I need a way to ensure all air is purged and there is no bubble trap while still being able to completely drain the line for storage.
 
Way to go Bigscience,
So I'm in the process of doing a similar HEX.
Where you able to get the 1/2 inch stainless in a coil or did you go with 3/8?
I've been looking for a 1/2 inch stainless chiller but have not found one yet.

Thanks, Kevin
 
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