1.1 Introduction
Sieve equipment is a kind of machine fabricated to be used in separating solid particles. Naturally its made of separation in similar to slow sand filtration, and this is a term used in unit operation, but sieving is a piece of unit operation carried out.
This sieving equipment works by allowing solid particles of different sizes to pass through the pores or the aperture, which consists of orderly, arranged sets of sieve in a manner of the particles sizes and shapes.
Sieve equipments are of different types and sizes, the types though is not a determinant of the motion, but the seize is a major determinant. The major of the type are the commercial and industrial types of sieves with shockers, and are usually constructed in big form. The minor of the types of however is the small scale sieve, which is often constructed, in small form. Most of these three types are electrified and carries time and regulator. Their movement is either in zig zag or up and down (vertical) motions, but latest research verified that the movement could be in both up and down and zig zag combined, although it is a lot more costly.
Their equipment for solid particles size analysis are mostly used in the separation of solid particles, in the pharmaceutical industries, gold refinery as well as in diamond companies and because of its use in these industries and factories, the equipment is not been commonly.
The sieve were fabricated in such s was t to allow particles of different size, to pass through the mesh or proprs of the sieve plate after a short period of time. Basically, sieve equipments consist of a set of sieves preferably with the quality of shocker in accordance with its speed range. The speed of the sieve shocker motor ranges from 0.0002pm (revolution per minutes 0.1200 r.p.m, 0-1500 r.p.m upwards to 2600 r.p.m and are normally use din abounded factories and industries.
The sieve equipment operates best when the solid particles is in their coarse and fine form. The equipment has high sensitive efficiency, but only few have been constructed since the development of separation of particle. This is as a result of the losses incurred and the procedures involve and also the labour needed to clean the sieving plates and to handle the sieve equipment.
The sieve shocker on the other hand is a device used to shake or vibrate a shocked column of standard sieves and test trays from the top (with large openings) to the bottom (with small openings) and a receiver (pan). The sizes of the mesh are in descending order of 17.5mm and 7.3mm, 3.9mm, 2.0mm, 1.5mm, 0.04mm and 0.08mm.
The shaker is an electrical device which consist of an electric motor with capacity 1.5 r.p.m (Revolution per minutes) which does the vibration and causes the shaking of the sieves; a capacitor of 2700 which storps the current, the sieve on/off switch, a spindle was placed off centered in the motor to enable the vibration in a zig zag direction.
The sieve shaker is the most important part of the sieve equipment because without the shaker, there will be no vibration at all.
1.2 Background of the Study
A standard sieve is a conventional sieve which incorporates both the diameter of the wire and the number of mesh per millimeter, and this information helps to clarity the ratio between the opening in sieve and the opening in the next small sieve.
A common set of standard sieve is the tyler standard sieve series is the . It is characterized by the installation of 200 — mesh sieve wire diameter of 0.053mm. This therefore, gives a clear opening of 0.074mm square.
The sieve analysis shows that percentages of particles fractions that passes through 10-mesh and remains on passes through 30-mesh, through 20 mesh and remains on 30-mesh, through 30-mesh and remains on 40mesh and 80 0n. This analysis must be accompanied by the specification of the diameter of wire that produced the opening and which varies with the pores of the sieve. And analysis of a sieving operation is carried out by placing a sample on the sieve with the largest opening arranged to be at the top most level. Below this first apartment are series of sieve with decreasing size opening arranged in descending order in accordance with the expected dimensions of the products. In its operation the feed material are pourpil on the sieve surface and carefully agitated. The under flow passes through this sieve openings and the overflow retained.
1.3 Aims and Objectives
It then implies that the sole function of a sieve is to separate any material feed into two fractions undersize and oversize. The efficiency of sieve operation is a measure of degree of separation of retaining all the fractions larger than cut diameter as overflow and all those smaller than cut diameter as underflow. It is very obvious that this task is a difficult one and no sieve equipment can over achieve this fit even with the present advancement in technology. A high momentum should be impacted to particles on throwing, in order to sustain high rate of contact and eliminate or reduce the chances of blinding and cohesion. The major aim if to achieved a separation of underflow from the overflow particles introduces in the sieve.
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