Question on coil size and length

[twojaythomo]

Hi all been looking around trying to find out information on sizing for coils but nothing is really show up much, my questions is I have a 63mm boka build, packing will be 1.5m hight and is considering a 2000w heating element would this coil I make be ok its 280mm long and 45mm wide with a piece of 19mm as a coldfinger or should I use less heat or make another coil, I really not sure.

[bt1]

It will do nicely.

The higher flow rate with what looks like 3/8" will cover np. Cold fingers are real good given the pressure drops to the core tube...helps.
If I could suggest one thing is to extend the cold area/chill zone by wrapping the coil in stretched out scrubbies. It then loosely fills the gap to the tube wall and being in contact with coil extends the chill area of the coil effectively.

Used this design in hybrids for ages and works well.

she's coming along nicely.. won't be long and you'll be considering naming it officially.

enjoy
bt1

[twojaythomo]

Thanks bt1 didn't think anyone wanted to answer this question, just wanted to be sure before I go ahead and start soldering and putting together the condenser part and yeah thanks for the advice on the scrubbers to fill the gap between the coil and pipe edge.

I have my furrels, reducer and clamps coming tomorrow I hope so will have all the parts to finish my column just need a element and tap for the keg.

[Yummyrum]

:text-+1:

[woodduck]

Is that 6mm tubing? If so based on what I use in my bobakob it should be ok. Mine is a 2600w element and I run a 180mm long double wound coil with no probs I don't run my water flat out either you only want to knock the vapor down not cool it right off warm distillate going back down the column I think is better. Best way to know is run it with water steam if it knocks that down you'll be fine. Just my opinion hopefully some of these other more experienced blokes may help more.

[twojaythomo]

Sorry just to clear things up the tube diameter is 9mm with 19mm core tube.

I also have a 70psi 3l/m water pump using my pool for cooling :D

[woodduck]

Best way to know is try it but I think you'll be fine as long as there's no kinks in it you'll be suprized how much they can restrict flow.

[twojaythomo]

There is a small place where it just started to kink over but not much ill hook it upto my pump and see how many liters it is putting out a minute, oh and one more thing I have been tapping it for ages and still blocked by the salt can I flush it out with water or will it go hard?

[woodduck]

Not sure on that one somone else might have to help you out there

[benmick6]

heated swimming pool. nice for winter.

[twojaythomo]

I got the salt out, just kept dropping the coil from ankle height on the cement to loosen the salt then tapping it in my hand all come out in about 5-10 minutes :handgestures-thumbupleft: lol but do have another question regarding the condenser part if I would like to use it has a pot still how long should I make the condenser part and should I have a large take off like 12mm or will 9mm still be ok.

So much to know but don't really seem to be able to find the answers to these questions.

[woodduck]

Sorry mate not sure what your on about I'm still new myself but I think if you want to run a boka in pot mode all you do is take the packing out so it doesn't reflux so much I don't think you need to modify the take off or anything else.

[twojaythomo]

Sound like the answer I was after lol. I will just use 9mm take off tube I think.

[woodduck]

That would be more than big enough for a boka usually it's only 6mm cause you usually use a needle valve and are only collecting a drip or two a second so it doesn't need to be big.

[bt1]

Two,
most folk would solder on tap fittings or snap on fittings to feed and take from coil I think is what your chasing in earlier question.
personally go 6mm to a short piece of 1/2" / 12mm then braze on a hose joiner cut in half. they then simply click onto normal hose snap fittings.

http://www.bunnings.com.au/hose-fit-connector-holman-12mm-2way-coupling-brs-8021hb_p3110586

simply cut in half, file lightly braze onto 12mm/1/2" copper

bt1

[Yummyrum]

Have read that a needle valve even fully open can hinder the output in pot mode.Some remove this for stripping.
You could use a ball valve.I have one on my LM/ VM head .It will fix the stripping issue but is fiddly as when using to adjust LM output

[twojaythomo]

All great ideas thanks guys I did think about the tap fittings for my coil as my other HBS reflux has the same setup so good.

If it did go 9mm takeoff with a needle valve would the be any negvitive reason for not doing this, wouldn't this help if I was going to do stripping runs just dont know the effect on a finishing, can't really see any if the valve is set to 1-2 drops/m.

This will be the last one I get to buy/make so I just want it to be right thanks guys.

[C2H6O]

Two,
most folk would solder on tap fittings or snap on fittings to feed and take from coil I think is what your chasing in earlier question.
personally go 6mm to a short piece of 1/2" / 12mm then braze on a hose joiner cut in half. they then simply click onto normal hose snap fittings.

http://www.bunnings.com.au/hose-fit-connector-holman-12mm-2way-coupling-brs-8021hb_p3110586

simply cut in half, file lightly braze onto 12mm/1/2" copper

bt1

Such a bloody good idea, i used barbed connectors and hose clamps; cost five times as much and makes put up and take down a bit of a bitch.
Looks like i have a job for the weekend.

Cheers

[twojaythomo]

Today I solder the coil parts together..... 6 times, half a roll of solder and still leaking lol geez I really can not solder, going to pull it apart tomorrow and try again.

[Yummyrum]

Clean all surfaces with sandpaper or SS scrubbers until shiny copper ...apply Solder Flux ( not borax style brazing fluxes) apply just enough heat to start bubbling flux ,then apply solder .

If you are using Burnzomatic flux paste then piss it off and get some liquid solder flux