Design, Fabrication And Performance Evaluation Of Pedal Operated Groundnut Decorticator

INTRODUCTION
1.1 Background to the Study
Groundnut (Arachis hypogaea) is a species in the legume or beans family (AshishandHanda, 2014; Atiku et al., 2014). It was first cultivated in Peru. Its seed contain about 63% carbohydrate, 19% protein and 6.5% oil. Groundnuts are grown in tropical and subtropical climate regions and warmer parts of temperature regions and it is low growing annual plant and has a variety of uses. Prior to its usage however groundnut need to undergo preprocessing which include drying and shelling. Removing of kernels from the pod is generally referred to as shelling or “decorticating” (Maduako et al., 2006). In Nigeria groundnut is mainly decorticate by hands (traditional method). This method is not hygienic as dirt from hands and mouth could pose health risk from the nuts. (FAO. 2001).
Shelling is a fundamental step in groundnut processing as it allows the kernel and hull to be used as well as other post harvesting technologies to take place such as oil extraction or in hull briquetting (Pradhanaet al., 2010). Shelling is usually carried out on the farm just before the farmer sells his product for the following reasons: Kernel do not store as well as nuts in the shell and groundnuts in the shell are fifty per cent heavier than kernels alone and therefore costlier to transport. Shelling can generally be done by hand or machine. Hand shelling is the process in which the pod is pressed between the thumb and first finger so that the kernel is released. In mechanization now we use large and smaller machinery for groundnut shelling. These machines are used in industries where large production is required. There are different methods of shelling and different machines have been fabricated and used to shell wide variety of crops under different conditions (Nyeaanga et al., 2003., Atiku et al., 2004; Gitau et al., 2013; andMaduakoet al., 2006). The peasant farmer cannot afford this machine because they are too costly and complex in operation and maintenance. Also the operator had to be trained and spare part imported. These factor increase the overall cost production which does not make any economic sense to the farmer.

1.2 Statement of the Problems
Research shows that groundnut has an inherent poor storage life, if not threshed after harvesting unlike some other crops, but in threshed forms, it can be stored for a very long period of time (Onuoha2010). Therefore, to overcome the problem associated with manual threshing and quick rate of insect infestation after harvesting, the development of groundnut decorticating machine is of paramount. Traditionally the seeds are left in the pods which would then be stored in a pot and would only be shelled when they are needed for cooking (Ngugi, 2007), shelling is one by hand or beating with a short stick or pestle and mortar, followed by winnowing (KaulandEgbo,1985). The constraints such as fatigue, high time energy inputs and inefficiency in manual shelling of groundnut led to design and fabrication of pedal operated groundnut Sheller that will go a long way in solving the problem of rural farmers that are engage in groundnut production at small and medium scale level.

1.3 Objective of the Project
The main objective of the project is to design and fabricate a pedal operated groundnut decorticator that will remove and separate the groundnut seed from the hull for domestic and industrial uses.
The Specific Objectives are to:
i) determine the physical properties of groundnut seed in relation to the design of pedal operated ground decorticator.
ii) design and fabricate a pedal operated groundnut decorticator
iii) evaluate the performance of the decorticator in terms of decorticating. Efficiency, percentage of breakage, percentage of shelled seed throughput capacity.

1.4 Justification of the Project
Due to high lose that are recorded due to lack of adequate power supply, these are expected to be achieve at the end of the project.We can save the time and money by using pedal operated groundnut decorticator, limited number of labour will be required, groundnut will be available for domestic and industrial use. The fabrication of the machine will encourage the farmers to grow more groundnuts.
The machine would overcome the traditional method by reducing wastage due to crack or crushed groundnut, to increase the efficiency, to reduce the hard work and to reduced time to shell the groundnut, to develop a low cost machine which can be used by farmer to convert their semi-finished (shell groundnut) into finished product (groundnut) and it satisfies the need of village people to earn more money.

1.5 Scope of the Study
Groundnut is the sixth most important oil seed crop in the world and is widely cultivated in Nigeria. The project work is limited to groundnut seed. The variable factors to be considered in this study were feed rate and characteristics of the operator (weight, height and knuckle length).