Airlock (untested)

Airlock used to prevent over pressure in fermentation containers for beer & wine or to prevent contamination from air exposure for certain biology experiments.

Water is slowly added to the outer chamber and flows into the inner chamber thus preventing ambient air from entering the container through the center pipe.

Gas build up in the fermentation container flows up the center pipe causing the water level in the inner chamber to lower until the gas can escape through the holes at its base into the outer chamber. Once there the gas will rise through the outer chamber and escape through the side vents near the top.

To prevent dust from making the water in the airlock muddy while still allowing for the monitoring of gas activity and water level, the top should be covered with a clear material such as a piece of clear packing tape.

EDIT: I've gone ahead and designed a simple lid with .4mm clearance to fit loosely enough to be removed without disturbing the airlock. Print this