Groundnut is an important crop containing oil. Oil extracting machine separates the oil contained in the groundnut seeds. This oil extracting machine is an electro-mechanical device. It consists of a gear motor purred using electricity. A base, stirrer, stirring shaft and stirring bowl are coupled together using different joining methods. The construction is aimed at reducing manpower requirements and increasing efficiency in oil extraction 26% of the time when compared with the traditional method. This is achieved using various mechanical operations. The materials used are mild steel, stainless steel, galvanized metal sheets and galvanized flat bars. The extraction took place at an approximate speed of 15.72 rpm. The minimum quantity of the grounded groundnut the machine can take at a time is 6.5kg and it extracts about 60% of the groundnut oil content the approximate cost of the machine in N 81.481.25 we recommend the machine be constructed using gasoline or diesel engine so that it can be used even in areas without electricity.
Background of the study
Groundnut seed (Arachis hypogea), also known as peanut or earthnut, is the most common oil nut grown as an annual crop on about 19 million hectares of land in tropical sub-tropical and warm temperature regions of the world. It is grown principally for its edible oil and protein. The seed content of the seeds is between 45% and 55% depending on the variety (Wood roof, 2003). To remove the oil content from the groundnut seed, the process known as oil extraction, expelling or is carried out (Young, 2005).
In Nigeria a survey study conducted in some northern states (Kano, Kaduna, Adamawa, Niger, Bauchi, and Katsina) showed that traditional groundnut oil extraction is a profitable business which is mostly done by women. It was also Found out that out of 436 processors of groundnut oil in three of the States (Kano, Katsina, and Kaduna), 74% said that they were processing it for income generation (Naumi 2006) Groundnut is of course a very important raw material for industries but is presently underutilized, despite of its potential for conversion into various edible and commercial products, such as, shelled groundnut, roasted groundnuts, butter, groundnut oil and groundnut cake (Sulaiman, 2008).
Preliminary studies showed that groundnut seeds contain 42% to 50% contain o f oil and most of the world groundnut processing is done for oil. It is a desirable cooking and salad oil, because of its quality, containing about 80% unsaturated fatty acids, such as oleic and limonitic acids and so much protein (Young, 2008).
Traditionally, groundnut oil extraction involves shelling the groundnut pods, roasting the shelled groundnut seeds, de-skinning/winnowing the roasted groundnut seeds, milling the cleaned groundnut seeds and Among the different method of oil extraction (traditional, mechanical, chemical and mechano-chemical methods (Ewaoda et al, 2005). Study revealed that 75% of the rural women engaged in groundnut processing used the traditional technologies which are labour intensive and the consuming (Dunmade, 2006).
Thus, groundnut seed processing represents an important activity for women In recognition of the importance of the activity, as outlined above many studies were carried out with a view to improving the process. Aliyu (2008) conducted a study to evaluate the traditional groundnut oil extraction process. Results revealed that apart from the drudgery involved, of time is wasted in the activity. A similar study by Ibrahim (2010) in a different location arrived at same findings and recommended improved equipment for small scale groundnut oil extraction. This recommendation prompted different technological interventions, in the form or developing simple devices for roasting, de-skinning / winnowing and kneading. Hydraulic press and screw expelling machines were also developed to avert the drudgery and inefficiency involved in the traditional method (Ibrahim, 2010).
The traditional use of mortar and pestle manually to process groundnut seeds for all is a serious problem to the women that are engaged in the groundnut oil extraction business. The method is not only tedious and time consuming, but also a serious drudgery to the women. It involves the following sequence of operations: shelling, sorting, roasting, cooling, skinning, winnowing, milling, (grinding to paste), kneading (oil extraction), frying the residue to cake locally called “kuli-kuli”. Kneading was then identified as the most tasking and energy consuming among these operations, which underscores the need to develop a motorized machine (Maigida, 2005).
The institution for Agriculture Research (L.A.R) at Ahmadu Bello University, Zaria developed a traditional model for groundnut oil extraction in 2000. The model was operated manually. But the mortar was installed and commented to the ground for stability, and the pestle was clamped on the mortar (Maigida, 2005). Another work done at National Agriculture Extension and Research Liaison services (NAERLS) Ahmadu Bello University, Zaria (Abubakar, 2006) attempted to replace the traditional mortar and pestle with manually operated drum chamber and a stirring shaft-and-finger mechanism.
Also a motorized model of groundnut oil extractor was designed constructed and tested at Agriculture Engineering Department A.B.U Zaria (El-Okene, 2007), The main features of the oil extractor include the kneading head, the conventional mortar, the transmission unit and the supporting frame. The intended quantity or paste is poured into the mortar and the machine is set up for kneading. Once the electric motor is switched on, rotary power is transmitted to the kneading shaft to the input shaft on which the kneading shaft is hooked. Kneading is accomplished by the centrifugal effect of the rotating fingers on the oil molecules in the paste, with water added gradually as the process progresses until the end. It observed that the average kneading time per unit weight decreased (Ajimotokan, 2010).
1.1 STATEMENT OF THE PROBLEM
Groundnut has been develop and constructed by some researchers in different sizes, shapes and the materials, mostly for the industrial uses. Such extractors can not be afforded by small scale and the low income oil millers. In other to assist the small scale millers in local community, small scale groundnut oil extractor need to constructed with locally sources materials.
1.3. AIM AND OBJECTIVES
The aim of the project is to design and construct an improved groundnut extractor that is durable with its materials locally sourced.
The objective a groundnut oil extractor machine
i. To construct a groundnut oil extractor machine that is durable.
ii. To design and develop a machine that is affordable
iii. To improve the quality of extracting oil from ground seed
iv. To reduce the cost of production of groundnut oil extractor
v. To reduce waste and increaseextraction rate.
1.4 SIGNIFICANCE OF THE PROJECT
The design and construction of groundnut oil extractor would be of economic important to the small oil millers, since most of them cannot be afford existing machines due to large cost of purchasing them. The availability of the machine would improve the practice of healthy an edible oil. As it would eliminate the traditional methods of extracting oil which is most times tedious and unhygienic. The machine would enhance high performance, save time energy. More so the project would be beneficiary to others who might want to commence research on extractor of oil from groundnut seeds.
1.3 SCOPE AND LIMITATIONS
The scope of the project covers extraction of oil from groundnut seeds, The construction would be limited to a capacity of average 6.5kg per milling of the groundnut seed.