VM Still Valve Discussion

[ExperiencedNovice]

There are many valves out there people use to control the flow of vapor in their VM stills. I have tested most of them at a novice distiller level and have some questions/thoughts I wanted to bounce off some more experienced members who have maybe drawn different conclusions than myself. For the sake of this discussion I argue that against common belief, butterfly valves are the best valve for a beginner VM setup. After testing other valves such as Ball Valves, Gate Valves, and diaphragm valves, it seems as though the only one that does not have some sort of cavity/well that can collect condensed vapor and smear your run is the butterfly valve. Actuating a butterfly valve at any % opening does not create any pockets that turbulent vapor can passively reflux and create a pool within the distillation path, and with a fine enough control handle you can become very accurate with % opening to achieve your desired reflux ratio. See below images for where I have experienced condensate pooling. Keep in mind for all of my testing there was no affordable way for me to cleanly insulate the valve body itself, but only the piping before and after the valve. With perfect insulation the pooling liquid may vaporize again but for most novice distillers, perfect insulation will not be done for either lack of understanding, or lack of tools to do it properly. Please share if you agree, disagree, have seen other results, or have fixed the above issues with any of the valves I've listed. All valve image sections are shown in an open position.

Gate Valve.JPG

Ball Valve.JPG

Diaphragm Valve.JPG

Butterfly Valve.JPG