Colling Valved Reflux

grant · Post by **grant** » Thu Apr 27, 2006 3:35 am

I've looked about but can't find an answer.
I have the valve reflux still as posted a while back. after a few runs the other day im sitting it at 78deg and getting a good 96%ish out of it. which is all good and fine.

Im still a little unsure on how much water i should be running, im just taking lots of guesses until its right.
Rather then stuffing around with it is there a simple solution to it ie so much coil = so much water??

MyDBear · Post by **MyDBear** » Thu Apr 27, 2006 4:17 am

The top of your condencer is open to the atmosphere,if there is no cooling water vapors will excape through this vent,so use just enough cooling water to knock down these vapors.

Thorin · Post by **Thorin** » Thu Apr 27, 2006 9:14 am

yeah.. you'dd rather want to be running too much than too little...

what if you had itt finely adjusted, and then something happened with your inhouse waterflow (chance of this happening mey be very low, but lets say like a pump malfunction ofr something)... it would not be very good....

btw... a pump malfunction would probably be a huge ass problem if you run a large amount of water too

grant · Post by **grant** » Thu Apr 27, 2006 2:23 pm

the reason i ask is previously i was having trouble keeping the thing at 79 78 deg, was allways at 82ish. This was because i was running too much cooling water, which i cant work out. ???

I don't use recirculated water, just straight through, where i get it running it doesn;t use much water at all. i sit the temp alarm on and it will run happy for hour get me 1L of 96 then i adjust to slow it down some. this is where a lot of stuffing around is when i increase it gets hot, so i fiddle around for a while until its at 78 again. even at full reflux and wrong water it will get hot.

knuklehead · Post by **knuklehead** » Thu Apr 27, 2006 2:48 pm

The cooling water flow through the coil on an offset head reflux still should have no effect on the head temperature. If you have enough flow to knock down all the vapour then the returned reflux will be what is controlling the head temperature, not your water flow. If your column stabilizes at 82 C then there is something very wrong and it has nothing to do with the cooling water flow.
Like Thorin said, better to much then "just right". I used to play around with it to get it "just right". This worked great until one day as I was running my wife decided to take a shower while I was running. With the shower running it effected the pressure I was getting to my condenser and I started to lose vapor. I don't worry about getting it "just right" anymore, I make sure I've got enough flow even if the dishwasher, washing machine or shower should start to draw water.

Swag · Post by **Swag** » Thu Apr 27, 2006 2:50 pm

Too much cooling water is not going to raise your vapor temperature. Too much heat will.
Turn down your boiler heat to reduce your vapor temperature. I use propane which is nice since I have virtually unlimited range of adjustment.
What's your heat source?

grant · Post by **grant** » Thu Apr 27, 2006 2:59 pm

hmm i remember someone else posted another time saying they had the same problem but couldn't work it out either, when running a lot of cooling water the temp would increase.

ok what temp should the hose be putting out once passed through the coil, should be fairly hot to touch like hot water with a bit of steam?

when i was getting a hotter head the water was coming out cold. think i read too cold won't hit the alcohol so no reflux.

Mind you my systems needs to improve i have a fuull garden hose on the floor in a coil, with a tap around the corner. I noticed sometimes i stand on the hose when adjusting so it clamps off some of tha water

Might shorten the hose and put a tap at the still so i can control it from there.

Just wanted to know if there was a calculation i can do to work it out or a rough amount. Im very happy with how its running at the moment.

Swag · Post by **Swag** » Thu Apr 27, 2006 3:06 pm

Could you describe your still again? Do you have a Nixon / Stone offset head?
If you do there are only two things that will reduce your vapor temp. Reduction in boiler heat or an increase in reflux liquid.
Adjusting your cooling flow will condense more or less vapor. If it just warm coming out of the return you have it adjusted effeciently.

grant · Post by **grant** » Thu Apr 27, 2006 4:45 pm

1500w element, sits at 78 once adjusted and gets me good results.

i think too cool water is not making enough reflux so the temp is rising??

possum · Post by **possum** » Fri Apr 28, 2006 6:39 am

Your smallish boiler could be causing some of the trouble grant. The higher boiling alcohols will come across sooner than in a 15.5 gallon keg.

It is hard to say exactly what is happening, but this is my suspicion. Once the first liter of high proof comes out, it is reasonable for the head temp to climb if nothing is adjusted.

Swag · Post by **Swag** » Fri Apr 28, 2006 6:48 am

I thought the same thing Possum.
As soon as you have boiled out most of your alcohol, your vapor temperature will naturally rise since the ratio of water to alcohol is increasing. Since you have such a small boiler this will occure fairly quickly.

grant · Post by **grant** » Fri Apr 28, 2006 3:32 pm

Yeah could be, not to worry i'll just keep going as i was.
I will get 1L out of it in not much time at 95 96% after that i adjust the reflux and output to slow it down, with a 20% wash i should be getting about 1.4L out of it, which i am getting close to.

Don't think i want to change it, it's fairly quick to heat up and run. If i feel like doing a few runs in the day simply put a fan on it for 5 min so its cool to open refill and away i go again.
Thanks for the ideas anyway, i might try and improve the water setup i have with a small tap at the still.

michaelb · Post by **michaelb** » Fri Apr 28, 2006 9:53 pm

Where I live it gets quite warm and the water lines are not buried deep enough to offer sufficient cooling so I pre chill the water. I have a freezer in the garage and run the water to and thru the freezer with a 25 foot coil of copper inside. Dont forget when not in use the line should be blown clear or it will freeze. To see vapor loss, I use a flash light and look for the shadow but you can usually smell it.

grant · Post by **grant** » Sun Dec 17, 2006 3:36 am

update on this, has been a while.
Too much water was the problem, i now run the water until there is very little vapour coming out the top. With a small torch and a dark room is easy to see.
Sits on 77 78, get a steady output (solid trickle) and high reading 95 96 %.

Water needs to be readjusted towards end of run.

I get about 1.3L out in 1.5, 2 hours

thanks again to all that have helped, im happy

Post by **Grayson_Stewart** » Sun Dec 17, 2006 3:13 pm

You honestly check for leaks with a torch in a dark room?

Post by **Husker** » Sun Dec 17, 2006 3:56 pm

Grayson_Stewart
You honestly check for leaks with a torch in a dark room?

I think torch==flashlight

H.

grant · Post by **grant** » Mon Dec 18, 2006 3:42 am

hahaha yes a flashlight as you call it, not an oxy torch.