1.1 Introduction
A Laboratory Centrifuge is a piece of equipment generally driven by an electric motor and some older ones usually spun with hand, that puts an object in a rotation around a fixed axis, applying a force perpendicular to the axis. It spun liquid samples at a high speeds and thus creates a strong centripetal force causing the denser materials to travel towards the bottom of the centrifuge tube more rapidly that they would under the force of normal gravity. By the same token, lighter objects will tend to move to the top of the tube. The major distinguishing features between centrifuge types are speed and capacity.
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Limitation of the study and Definition of technical terms.
1.2 Background of Study
The traditional method as in the case of oil palm fruit involves boiling the fruit in water which makes it easier, possibly by breakdown of oil cells and coagulating the protein to squeeze off the succulent fleshy part. By washing the mass in water the oil floats and is skimmed off. This is further cooked to get the right quality and colour. Other traditional methods as in the case of groundnut, melon and similar seeds in question involves pre-grinding with mortar or other local grinding equipment and hand pressed to extract the oil. Groundnut is an annual crop, which can be cultivated at any time of the year with proper irrigation. It is also known to thrive best in rich sandy loam soil (Woolrich and Carpenter, 1933). In Nigeria, yields as high as 200lbs (90kg) has been obtained (Irvin, 963). Nigeria is among the three largest producers in the world with about 6.5% of the total world production (Pulsegroove, 1968). Groundnut contains 25% protein and 45-50% oil (Muller, 1988).
The harvested nut can be useful in so many ways. The husk could be used in making fertilizers or be fermented into alcohol or acetones while the whole kernel yields the oil and the cake. Groundnut oil shows good resistance to oxidation. Its fatty acid consists of about 20% saturated and 50% unsaturated lipids. It also contain up to 30% linoleic (essentially fatty acid), which plays a major part in human diet. Having seen the high economic importance of groundnut to the economy, the diet of the average Nigerian and the rising demand for vegetable oil in the market, it becomes inevitable to quickly replace the traditional method of separation of groundnut oil slurry which is rather wasteful, unhygienic and labour intensive with a mechanized method. In view of these, mechanical filtration by wide-angle conical screen centrifugal filter is necessary. It is therefore believed that this work will produce a conical screen centrifugal filter which is affordable by an average local processor of vegetable oil and which will greatly improve vegetable oil filtration.
In a typical laboratory, there exists three different sizes of centrifuges. The smallest are the microfuge centrifuges. These are made for spinning 1 to 2ml plastic centrifuge tubes at sped up to 12 or 13 thousand rounds per minutes. They have very small, light rotors in them (the rotor is the part of the centrifuge that contains the holes for the sample tubes) which speed up and slow down rapidly. They are convenient for low to medium speed centrifugation of small quantities of materials.
The next common size centrifuge is the large super speed centrifuge that have up to about 20,000 rpm and can take tubes of various sizes, depending on the rotors (the larger the rotor, the slower the maximum speed). Finally, the third size is an ultracentrifuge; speeds up to 70,000 rpm are available on typical modern versions. Its size of tube and maximum speed vary from rotor to rotor.
Before centrifuging, the sample is a tube, a mixture of solutions of differing specific gravities with no clear separation. This makes it impossible to determine how much of each solution is present. After spinning, the samples in a centrifuge, the different solutions in the sample are separated into layers with the heaviest at the bottom of the tube. The quantity of each solution can now be readily determined. Therefore, in Nigeria where the research was carried out, the activities that was conducted is to Design and Fabricate of A Laboratory Centrifuge.
1.3 Statement of Problems
Investigation revealed the problems of the existing design and construction A Laboratory Centrifuge research work which are the cell are exposed to a high gravitational force, which can alter the cell structure; the recovery of fragile microalgae biomass requires low-speed centrifugation; the salt contained in the microalgal culture medium can cause rapid corrosion of equipment and large-sca;e processes require costly equipment such as; continuous centrifugates (Pires et al., 2012 and ScienceDirect, 2021).
1.4 Aim and Objectives of Study
The aim of the study is to design and construct a Laboratory Centrifuge using local materials. In achieving this aim, the following specific objectives were laid out as follows:
- To design a Laboratory Centrifuge using local materials / components
- To construct A Laboratory Centrifuge using steel for the construction of the body, aluminum for the centrifuge head, rotor and buckets, made the centrifuge cheaper and more adaptable to the local environment.
