non-jamming/clogging cesspool mixer

thingiverse

My grandfather's holiday house is equipped with a septic system, which means it relies on a cesspool to handle wastewater. To keep this process running smoothly, the cesspool comes with a mixer that rotates daily at an impressive 1000 rpm in both clockwise and counterclockwise directions. Unfortunately, the original mixer failed and sank to the bottom, prompting me to design and print a replacement. The new mixer had to meet several key requirements: it needed to fit through a narrow opening of just 12.5cm (under five inches) in diameter; function effectively in both clockwise and counterclockwise directions, necessitating a symmetrical design; have smooth edges to prevent clogging or jamming; feature robust fins to resist breakage; and be made from a durable material that wouldn't dissolve easily. In the end, I decided to print the final design using Polymaker PC-max (polycarbonate) – ABS might also be a suitable option. The mixer boasts four M8 mounting holes positioned 25 and 30mm away from its central M10 hole.