Concentric reducer makes column flood-prone

[MartinCash]

Ok, I modified my VM head and added an inverted 2'' to 3/4'' concentric reducer inside, above the tee, to encourage vapour to travel down the takeoff arm. It worked very well, and I can now produce a good-sized stream of output with the valve wide open. I haven't sealed up the top and calculated the reflux ratios yet by running it as a pot still, but I was happy with the output rate.

One issue that cropped up was flooding in the head. I started to hear gurgling as the reflux traveling down was being pushed up at the 3/4'' choke point by vapour travelling up. I'd stuffed a scrubber above the choke point, and I think it was partly acting as a sponge and stopping the free drainage of the reflux. After a bid, condensate moved past the reflux condenser and tried to spill out the top (luckily I was handy with a towel). This problem only arose when I was using high power, and the vapous speed was very fast, but the spilling condensate was 92% ethanol and a fire hazard, so I was concerned about the potential fire danger.

Will next remove the scrubber above the choke point and see how that goes. Keeping safe and not burning my house are higher priorities at the moment than increasing my take-off rate, so I may end up removing the reducer altogether if it keeps happening. How common a problem is this?

MC