CHAPTER ONE

1.0  INTRODUCTION

Every year, the final year student of this institution in Higher National Diploma (HND) and the National Diploma (ND) into practice.

This is aimed at justifying the emphasis lead on practical work during the the course of study in the assigned to construct a tomatoes grader by the Mechanical Engineering Department, the Polytechnic, Enugu.

A tomatoes grader machine is an equipment used for grinding tomatoes and which can also grind other good crops.  This equipment comprises essentially of an electric motor, belt, pulley, transmission shaft, hopper, mills, spiral conveyor and stands [Nikola Tesla, 2012].

1.1   BACKGROUND OF THE PROJECT

Cassava originated from Latin America and was later introduced to Asia in the 17th century and to Africa in about 1558. In Nigeria, cassava is  mostly grown on small farms, usually intercropped with vegetables, plantation crops, yam, sweet potatoes, melon, maize,  etc. Cassava is propagated by 20 –30 cm long cutting of the wood stem, spacing between plants is usually 1-1.5 meters. Intercropping with bean, maize, and other annual crops is practiced in young cassava plantations [Bencini. 1991].

There are two common varieties of cassava, namely, the bitter and sweet varieties. The cyanide content differs as well as suitability for different growing and consumption conditions. Usually, higher cyanide is correlated to high yields. Nigeria is the world largest producer of cassava tuber in the world, producing about 34 million tonnes of the world’s 174.0 tonnes [Flach, 1990].

Over the past 25 years significant market opportunities for cassava have opened up in the animal feed industry, initially in the EEC (European Economic Community) countries but more recently for the rapidly expanding animal feed industries of tropical developing countries. Cassava roots compete with other carbohydrate sources, especially maize and sorghum, on the basis of price, nutritional value, quality and availability [Bamiro, 2006].

Cassava has several advantages compared with other carbohydrate sources, especially other root crops. It has a high productivity under marginal climatic conditions, which results in a low-cost raw material. Root dry matter content is higher than other root crops at 35-40%, giving optimum rates of 25:1 or better. Over 85% consists of highly digestible starch.

Cassava starch has excellent agglutinant properties which make it especially suitable for shrimps and fish feeds, replacing expensive artificial agglutinants.

The potential disadvantages of cassava roots are their bulk and rapid perishability, their low protein content, and the presence of cyanide in all root tissues. Through simple processing the disadvantages of bulk and perishability can be overcome. A stable product is reached when moisture content falls below 14%. Natural drying is widely used to achieve this objective. Drying also permits the elimination of most of the cyanide from root tissues. The dried cassava product thus has only one disadvantage with respect to other carbohydrate feed sources: low protein content. This can be overcome through price competitiveness.

For export markets, where transportation over thousands of kilometers is necessary, further processing to produce high density pellets is carried out to minimize transport costs.

Presently in Nigeria, the products of cassava are usually locally consumed and exportation is limited because the products do not always meet the international standards for healthy foods. Thus, the need to encourage the small scale (home production) of cassava product to ensure the quality of products and good hygienic values [Nweke, 1990].

From the survey conducted, it was discovered that most of the cassava graters in the research area are usually corroding (reducing service life) due to the acidic nature of the cassava fluid and materials used for the fabrication. To ensure all cassava products is free from any taste, odor, or infection by the iron content of parts (food poisoning) which may affect the quality of their contents (FAO/GIEWS, 2001) hence need to modify the design and use appropriate materials for fabrication.

The product tuber spoils after 2-3 days of harvesting, hence the need for processing into safer stable products. In view of the above-mentioned problems and the overall importance of the cassava products, the following objectives are required to address the shortcomings of the grater [Bamiro, 2006].

1.2        PROBLEM STATEMENT

the manual method of grinding tomatoes is called pounding. This method of evolves much human labor, wastes time,  changes the color of the ground tomatoes, and at the same time exposes the tomatoes to microorganisms during the pounding processes. This work was introduced to overcome these problems in that it grinds tomatoes electrically.

1.3        OBJECTIVES OF THE STUDY

The objectives of the study are:-

1. To construct tomatoes grader with local materials.
2. To construct a machine that is less in crop and domestic usage?

iii.                To produce a tomatoes grader that is lesser in vibration, weight and in size.

1. To modify the design of the existing cassava grater (dimensions) to the home use-small scale sizes.
2. To change the crude wooden drums used in cassava grating machines to lasting stainless steel and galvanized pipe.
3. To save time and cost of processing cassava products by the average family.

vii. To promote healthy consumption of cassava products.

1.4   SIGNIFICANCE OF THE PROJECT -It’s fast and can crush tomatoes as finely as any other mill I’ve used. It also can make fantastic crush tomatoes because the coarse settings are easy to adjust.

-It can grind faster.

-It doesn’t heat up the tomatoes like other tomatoes grader can.

-It doesn’t spew tomatoes anywhere.

-it does not change the color of the pepper

1.5      LIMITATION OF THE PROJECT

The limitations of this project are:

-It cost of production can be higher for students

-It’s noisy.

-The capacity of the hopper is smaller than other heavy-duty mills. you would need to fill the hopper more frequently than mills with a larger capacity.

1.6    JUSTIFICATION OF PROJECT

1. This is to promote indigenous machine and their producers.
2. To have a portable tomatoes grader constructed for domestic uses with a powered driven source.

iii.                To improve the economy and the country as a whole by neglecting imported blenders i.e producing machine that is affordable to substitute the imported blenders.

1. To be able to meet National Board for Technical Education (NBTE) requirement in awarding National Diploma (ND) in Mechanical Engineering.

REFERENCES

1. 2001. “FAO/GIEWS – Food Outlook No 3”. June 2001 p.9.Product Profile on Cassava.
2. Bamiro, O.A. 2006. Paper presented at the AERC International Conference on Accelerating Africa’s Development Five Years into the 21st Century, held in Tunis, Tunisia, November 22-24,
3. Bamiro, O.A. 2007. Lead Paper at the 16th Engineering Assembly of Council for the Regulation of Engineering in Nigeria (COREN), held in Abuja, Nigeria, August 28-29,
4. Bencini, M.C. 1991. “Post-Harvest and Processing Technologies of African Staple Foods: A Technical Compendium”. Agriculture Services Bulletin 89. Food and Agricultural Organization (FAO): Rome, Italy.
5. Cock, J.H. 1985. Cassava: New Potential for a Neglected Crop. IADS development-orientated literature series. Pub. Westview Press: Denver, CO.
6. Delta Youth Farmers Multipurpose Co-operative Society Ltd. 2002. Proceeding of the Workshop on Cassava Processing and its Socio-Economic Benefits.
7. Flach, M. 1990. “Gari Processing in the North- West Province of Cameroon”. Working Document No. 5. FAO Project CMR/86/017: Rome,
8. 1994. “African Experience in the Improvement of Post-harvest Techniques, Food and Agricultural organization of the United Nations”. Agricultural Engineering Service (AGSE) Support Systems Division Workshop, Held in Accra, Ghana 4th to 8th July. FAO: Rome, Italy. www.fao.org/docrep/W1544E/W1544E07.HTM
9. 2000. “Cassava: An Essential Part of Diet”. Championing the Cause of Cassava http://www.fao.org/NEWS/2000/000405-e.htm.
10. 2002. “FAOSTAT, Statistical Data Base of the Food and Agricultural Organization (FAO) Of The United Nations”. FAO: Rome, Italy.

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