Engr305 peanut sheller project
Background[edit | edit source]
This project stems from an established organization called The Full Belly Project. This group has provided the universal peanut sheller to several communities with the vision of reducing hunger in the developing nations. There are general guidelines on how to make a peanut sheller, but they can and should be adapted to the local materials in specific communities.
The sheller was first created by Jock Brandis, who realized the need for a mechanized peanut sheller on a trip to Africa. Peanuts provide a wide range of benefits, from preventing soil erosion to being a primary source of protein, but the women of the village felt that the work of shelling nuts was too labor intensive to grow them on such a scale. Brandis then promised to return in a year with a way to shell the nuts faster and easier, thus spawning the creation of the universal peanut sheller.
Description of Opportunity[edit | edit source]
The project that I am undertaking is the creation of a peanut sheller. It will be used in a developing nation where the diet is largely dependent on peanuts or other shelled nuts. The country where my sheller will be used has not been chosen as of yet, but will most likely be used in Africa or Asia. The machine will be most useful in villages where a considerable amount of time is used to process peanuts.
The peanut sheller will be used to expedite peanut processing. By being able to shell more than one nut at a time, the peanut sheller will increase production while at the same time cut down on the time spent on it. It must be made form local materials without much difficulty and have a lifespan of at least fifteen years. The use of local materials is very important because they will be used in villages where the resources and materials are taken from the local environment. Therefore, it will also be adapted to the specific location of where the sheller will ultimately be used. The lifespan of the machine is also important; it should last a fairly long time without having to be replaced. Otherwise, the users will be spending more time fixing or replacing the machine, which will add to the workload when it is supposed to reduce it. It should be easily replicable and simple to use. If it is not easy to operate, people will have a hard time adapting to it and will be less likely to use it. The ability to make multiple machines will give the users more freedom to choose when they do the work instead of having to wait for a turn or delegate a person to the task.
The people who will benefit most from this machine are the women of these countries whose labor spent on shelling peanuts will be dramatically reduced. The hours of saved time could be used for other responsibilities or obligations. It will also save women from tedious work that is exhausting to their hands. Versions of it are currently used now in several countries, primarily in Africa, and the reception of the sheller has been positive. The success of the existing peanut shellers reinforces the need for such a machine.
Criteria[edit | edit source]
Materials: The sheller must be made with local materials so that the cost remains low and the users are independent to make them on their own.
Durability/Longevity: It must have a minimum lifespan of fifteen years.
Efficiency: It must shell more peanuts than can be done by hand at a rate that makes the production of the machine worth the cost and time.
Low/No Maintenance: It should require little, if any, maintenance.
Replication: The sheller must be easy to replicate.
Easy to use: The machine should be easy and pleasurable to use. This means it should be comfortable and virtually effortless to operate.
Literature Review[edit | edit source]
The Universal Nut Sheller
The Universal Nut Sheller is a machine that can be used to expedite the shelling of nuts and thus increase food production on developing nations. It is made from materials that are easily accessible and fairly cheap.
A bag of concrete is relatively inexpensive, and the most common substance used for the main part of the sheller. In addition to being cheap, it is durable and will ensure a long life for the peanut sheller. It is shaped using a mold. The stand can be made of wood, half of an oil drum, or other sturdy material that can be fashioned into a level support base. The sheller also requires some metal parts, including rods, bolts, washers, and nuts. 
The sheller will increase the production of nuts, an important source of Calories in the form of fats and proteins. By improving the production rate of peanuts, the women and children of developing communities will have extra time to spend on other tasks and responsibilities.
Budget[edit | edit source]
|Item||Quantity||Cost Each ($)||Total ($)|
|Mini Peanut Sheller Mold Kit||1||223.88||223.88|
|12” Threaded Rods||6||1.4||8.4|
|6” Threaded Rods||6||1.07||6.42|
|Nuts and Washers||48||0.08||3.84|
|1/4” Vinyl Tubing||1||0.64||0.64|
|1/2” Vinyl Tubing||1||1.02||1.02|
Design[edit | edit source]
The basic design of the peanut sheller was based on the already existing sheller. There is a rotor, which is the inner, moving part of the sheller and the stator, the nonstationary outer shell. The original design is also equipped with some metal parts, including threaded rods of various lengths, metering plates, shafts, handles, nuts, and washers.
The purpose of my design went into finding alternative materials to supplement or substitute the use of concrete. My choices of materials were based on their potential availability in rural communities in developing nations. This led me to two strong potentials: clay and newspaper.
Construction[edit | edit source]
The construction of the sheller began with the pouring of the molds.
I made an all concrete sheller first, to serve as a control and example for my following attempts.
I then continued with making a mixture of paper and concrete. After making some testers with various ratios in plastic plant pots, I found the 50/50 mixture to be strong enough while also reducing the amount of concrete used. I was a little worried that some spots were weaker than others where more paper was, but the structure as a whole held together fairly well. I was also concerned about the small gaps left from the paper that could possibly allow rocks from the concrete to loosen up and get into the peanuts. These seemed like small issues, and the piece held together quite sturdily.
However, these seemingly minor imperfections were only exaggerated when poured into the stator mold. Because the stator is less than an inch thick in most parts, the paper and concrete did not hold together well at all. Even with mixtures containing more concrete or more water (to make it easier to pour and fit in the mold), the structure was just too thin and fragile.
My other alternative was clay. At first I tried incorporating the soft, yet solid, clay in with the cement. I wasn’t satisfied with the result because there were still large chunks of clay scatter throughout the material.
I then dissolved the clay in enough water to make a saturated liquid sort of goop, which I call liquid clay. In this form, I could use it to replace the water I would normally use to make the concrete while fully incorporating the clay without having big chunks of it. The testers I made in the pot plants were mixed well but pretty brittle, even with smaller amounts of clay.
I went ahead anyway and poured a 50/50 clay mixture into the stator mold to see how it would fare as an actual part of the sheller. When I removed the inner part of the mold, it looked very promising. However, when it was ready to be removed entirely from the mold, the whole thing just broke apart. It was too thin and brittle to hold its own, let alone be put under constant friction as a peanut sheller.
Although my attempts to supplement or replace the concrete did not turn out as I had expected or hoped, I continued working with the all concrete mold to see if I could find alternative parts for the metal.
The construction of the sheller is pretty straightforward if you have all the necessary metal parts. However, the mold kit that was sent to me lacked these parts, so I had to improvise by replacing or finding a way to make do without them.
For the top and bottom bracket, I cut a steel flat into the appropriate sizes and drilled them so as to be able to attach them to the machine. I did the same with two pieces of wood that I found around my house, and they did a comparable job.
The original sized peanut sheller kit has plates in the sheller to control the amount of peanuts to be shelled and prevent the machine from clogging up. I did not find these necessary for the mini sheller because the top of the machine is already so small and mine did not seem to have any issues with jamming.
Testing[edit | edit source]
The best things to use to test the sheller were, well, peanuts! I had issues with the peanuts breaking in half, but that is because the gap between the rotor and stator is not large enough to allow whole peanuts to pass through. It did do its job though, and the peanuts that come out are shelled.
Infrastructure[edit | edit source]
One of the requirements for the sheller was a long life with little to no maintenance. Because of the materials used, the machine should not need much repair if properly handled. The life expectancy of the current sheller design is fifteen to twenty years. And though the fiberglass molds are expensive, especially for member of a rural community in a developing nation, they are practically indestructible (again, if handled properly) and can therefore provide an indefinite number of peanut shellers.
The use of the sheller is basic; it requires little more than the rotating of a handle and a supply of peanuts.