Modifying the "Rab Maxwell" tube

[evanvine]

The tube, which consists of a tube within a tube, can be used for either chilling or heating.
The idea being that the warm, or cold water is sent down one tube and then returns up the other.
The problem is the heat transfer between the water in the inner tube and the water in the outer tube.





I think I've solved this by putting a third tube in, creating an "insulation gap" between the inner and the outer.



It has yet to be built!
The original was 22mm and 15mm.
The mod is 22mm, 15mm and 10mm.

I'm only really doing this cos I like playing!

 

[bobsbeer]

Should work. :thumb:

 

[bobsbeer]

One suggestion. Solder on 15-10mm reducers on the ends of the inner tube to create an air gap between the 10mm and 22mm. This will give you better insulation.

 

[evanvine]

That's exactly what I'm intending doing Rob, although not exactly as you sketch.
I left out the reducers in the above drawings as I couldn't arsed to draw them.

 

[bobsbeer]

It was hard to tell from your drawing Jim, but it looked like you were leaving the middle tube open to just be a dead flow area, hence my suggestion. But it should help reduce the heat transfer on the outer sheath. Good luck with it, and let us see the final construction.

 

[evanvine]

NP Bob, will take pics!
PS. I think a 22/10 reducer may be hard to come by. :whistle:

 

[bobsbeer]

You may need to use a 10-15 then a short length of 15 pipe and then a 15-22, and then a short length of 22 to the 22/15 tee. That would be the easiest way. Inside that the 10-15 to blank off the 15mm pipe, which could be inside the 22mm Tee. Then you can add a 10-15 on the 10 pipe and then a 90 degree to attach the water line. Shouldn't be too difficult to fabricate. A dry fit would be useful I think and then working out the soldering order. Have fun. :lol:

 

[Cononthebarber]

I'm sorry I may be thick but I don't get it? What is the tube supposed to do exactly? :lol:

 

[evanvine]

It acts (in my case) as an immersion chiller/heater.
I use one to control a constant temp ferment.

 

[Fil]

might be easier to just lag the inner tube with something impermeable like garden hose, silicone or PVC tube and seal it with some cartridge gun silicone?
if u get a thin walled tube u could also encapsulate an air pocket too.

also have u considered channeling the return back up in a spiral pattern to maximise its effect?

i used coax cable effectivly to form a spiral water guide round 10mm tubes in my counter flow tube chiller. the single core seems to hold the pattern,

 

[bobsbeer]

A spiral between the 15mm and 22mm pipe should help as it will increase the distance travelled. Which should allow more heat transfer. Holding it in place may be an issue, but maybe you could solder the inner wire core to the 15mm pipe before inserting it into the 22mm pipe.

 

[graysalchemy]

Is this more efficient than using a coil? I have a 10m x 10mm copper coil which I use with my Maxi chiller fro cooling, but I fear that it is rather cumbersome to sterilise properly before going in the FV and gets in the way in the FV, though it does do a good job. :thumb:

 

[evanvine]

I don't know about it being more efficient Alistair.
I use it with a Maxi cooler and a HERMS.




This is the Mk1 version.

 

[Vossy1]

It's probably less efficient than using a coil as it probably has a smaller surface area (can be checked quite easily) and due to a coils design is exposed to more of the wort. It's a personal choice but the reason I prefer solid chillers over coils is yeast 'wicking' on racking, the Rab design virtually eliminates it, especially when vertical
How are you getting on with it and the conical Jim?

 

[evanvine]

I'm well pleased with the Conical JP, and the Maxwell exceeds my expectations!

 

[Vossy1]

Great stuff

 

[evanvine]

Mod completed, please ignore **** soldering, hand eye not what it used to be.

Showing 22mm, 15mm and 10 mm pipes


complete with ball valve fitting for the header tank.