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Double Condenser in still

Posted: Mon Aug 24, 2020 9:36 pm
by Boreas

I am still in the planning phase of a reflux still, but happen to get 2 Condenser coils from a friend.

Had an idea that I can't figure out if good or bad. Also haven't found any information on the Internet.

Would there be any benefit in placing a Condenser at the top of the column linked inline to the Condenser in the off-set arm that collects the distillate.

Plan is for a valved reflux still.

Any input would be appreciated

Re: Double Condenser in still

Posted: Mon Aug 24, 2020 10:11 pm
by OtisT
I would recommend independent flow control for your two condensers. While your product condenser (PC) can be run as cold as you can get it with no ill effects, you don’t want to run your RC that way. The RC needs to be detuned when fractioning so you don’t overcool your reflux.

I’m curious. By a “valved column” are you referring to a valved vapor management (VM) column? (A CCVM being an un-valved VM)


Re: Double Condenser in still

Posted: Mon Aug 24, 2020 10:54 pm
by Boreas
Thanks for the reply.

I meant a Liquid Management Still with valves controlling the return and off take fluid.

Starting to think I am overcomplicating things.

Thanks for the info

Re: Double Condenser in still

Posted: Tue Aug 25, 2020 4:06 am
by Yummyrum
By valved reflux , I’m guessing you are planing on that 20+ year old design with the off-set condenser and two valves
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Re: Double Condenser in still

Posted: Tue Aug 25, 2020 9:25 am
by NineInchNails
Most builds use a reflux coil at the top of the column. This reflux coil should be sized properly so that it can knock down 100% of the vapor. There is a calculator here on the parent site that will tell you the length of copper tube based on its diameter and energy input.

Most builds use either a liebig condenser or a shotgun condenser as the take-off/product condenser. This condenser should also be sized to knock down at least 100% of the vapor based on energy input.

Take your time and study the different styles of reflux stills and understand how they work, not just how they look. There are really good pinned topics that outline their designs and how to run them. I am really glad I went with a VM still. The thing damn near runs by itself and puts out 195% neutral consistently. When product starts to dwindle, the run is about over, temp spikes and the run is just done.

If I had to choose another style, I'd probably go with a Boka LM (liquid management). It's super simple and cheap to build in comparison to most other styles. It's not complicated at all and easy to understand how it works.