Manual compactor #4: first operating prototype

The 20×20cm prototype was the first one we could actually test with whole bottles. We tested in a real street in Maptuo, Mozambique. It was only able to handle about 0.5kg of plastic (about 20 bottles), meaning it was too small to use in real operation. Even so, it taught us three important lessons for a very low cost in terms of materials.

Firstly, we learned that applying pressure with the lever fitted at the top meant that the compactor tended to tip over, towards the person tipping it.

Solution: We added triangular steel spikes at the corners of the base. On the dirt roads around Maputo, these dig into the ground and hold the unit in place under load.

Secondly, we saw how important it was for the lever rod to fit well so that it could apply downward pressure on to the ramming plate at the top.

Solution: we welded a forked metal bracket onto the side plate with a socket to hold the rod, a fixed pivot point that also tilts to allow the top plate to be inserted before each compression cycle.

Thirdly: we were able to simulate the rapid build-up and tear-down of the unit (remember... it will be carried from one collection location to another during each day).

Solution: to make field deployment faster, we added hinges connecting the base and side panels, so the compactor can still be flattened for transport but assembles much quicker on the ground.

This whole iteration took us a week and was done basically with left over bits of scrap metal that we were able to buy very cheaply from local metalworkers. 

Testing our 20×20cm prototype of a manual roadside compactor for plastic waste.