Still Spirits reflux still mods - end of the line?
I've just done my first (water only) run of my re-modified Still
Spirits reflux still.
For those of you without a good memory, the last mod I did was to put
a 1m X 25mm packed column onto it, giving me a purity of about 93%
over the course of a run.
Since then, I've been chasing those elusive last 2.something percent
by trying to turn my still into a complete reflux jobbie by taking
the output pipe and feeding it back into the column, with a needle
valve to draw off the distillate in adjustable quantities.
As I said, I've just done my first run and it's not good news. The
problem as I pointed out last time is that the condenser head of the
SS still is upside-down, so you have to feed the liquid for refluxing
back into the column lower down. The problem then, as I've just found
out, is that the vapour travels up both the rest of the column AND up
the reflux inlet pipe. End result is that the condensed liquid just
sits there, being "pushed" from both ends. There's no "flow" as such.
The only thing I can think of now is to use a non-return valve on the
reflux pipe, but I'd imaging all that'll mean is the refluxing liquid
will surge through when the pressure's up enough, and sit there when
it isn't. Hardly what you want for a nice stable separation.
Anybody else got any other ideas before I go back to the drawing
board or throw caution to the wind and build a Nixon Stone head