Prototype Construction

Our prototype consists of two separate modules designed to be used separately. It is possible to mount the crusher module so that the crushed nuts fall directly into the winnower. However, because of the different times required to crush and winnow the same amounts of peanuts and the added inconvenience of not being able to see the nuts while winnowing (due to the crusher being the line of site) most end users will likely prefer to use the modules separately.

The crusher module has some significant differences from the original design proposal. It was made from eight pieces: two wheels, a belt, a ramp, two sides, and two legs. For the assembly, first, 6” diameter holes were cut out of the sidewalls, at a distance of approximately 7” center-to-center. Next, slits were cut into the sidewalls that would allow for adjustability of the ramp angle with respect to the belt. Wooden legs were added at the end where peanuts are added so that the overall slope of the ramp would cause the peanuts to roll downwards. The distance between the ramp and the belt were adjusted according to the average width of peanuts tested and found to be approximately 0.3 inches.

The original design called for use of a tire tread to be used, as these are easy to obtain in Zambia. Unfortunately, this idea was not possible to do, as separating a tire tread from the sidewall requires a very specific machine, which Zambians most likely will not have access to. The belt that was used was constructed from an all rubber welcome-mat, which was cut and glued it into a 6.0 inch wide belt. This material had hundreds of little rubber nubs that helped create a variable force on the shells much like the tire tread would. For ease of construction and testing, a 6” diameter PVC pipe was used instead of wooden wheels. However, this method had problems because the belt would sometimes slip on the wheels, as the PVC has very smooth surface. The section of the belt where it was glued created a gap where there was less surface area in contact with the driving wheel. Ultimately, approximately 50 rubber bands under the driving wheel were added to improve the grip between the belt and the wheel.

The winnower module prototype consists of two sections. The first section creates the wind used to separate the seeds from the shells. The second triangular section was created during the testing process to catch the shells that are blown away and funnel them into a container. This second piece allows both the measure of the amount of seeds blown away, and preventing of the shells from being blown away, while catching any seeds that might be blown off the first section. For Zambians, this additional section may not be necessary.

Peanut Decorticator Prototype


Peanut Winnower Prototype


Decorticator & Winnower Prototypes together.