Please specify the inner diameter.
The calculator should help to estimate whether planned pipe diameters are sufficient. In other words, it should warn against diameters that are too narrow. For example, if you are thinking of building a still for 2000 watts with a riser made of 12mm copper pipe, i.e. with an inner diameter of 10mm, then the calculated steam velocity of 19m/sec will show what forces will be acting. Firstly, the calculation result illustrates the pressure that prevails in the still, and secondly, the strong acceleration:
- High pressure is a safety hazard, it reduces the alcohol content of the distillate and it increases foaming of mashes.
- Sudden strong acceleration of the steam makes the distillation unsteady. The still begins to oscillate, that is, to rock and ventilate.
Vapor speed is highest with pure water and lowest with about 88%abv alcohol in the vapor. However, it does not make much difference. After condensation, however, liquefied alcohol-rich vapor has considerably more volume than water vapor produced with the same heating power. So, at the same heating power, the distillate stream at the beginning of distillation is much stronger than at the end of distillation. The steam flow, however, changes only slightly. In practice, however, if the heating power is increased during distillation to counteract the decreasing distillate flow due to the falling alcohol content, the steam velocity is increased.
The calculated speed refers to normal atmosopheric pressure 1013.25 hPa. For every 10 hPa less, or about 87 meters of elevation, the vapor speed increases by about 1%. A negative pressure distillation at 500 hPa means about a double vapor speed.