Construction Of Sieve Equipment

INTRODUCTION
Sieve equipment is a kind of machine fabricated to be used in separating solid particles. Naturally, its mode of separation is similar to slow sand filtration; and this is a term used in unit operation, but sieving is a piece of unit operation is carried out.
The 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 sieves in a manner of the particle sizes and shapes.
Sieve equipments are of different types and sizes, the type though is not a determinant of the motion, but the size is a major determinant. The major of the types are the commercial and industrial types of sieves with shocker, and are usually constructed in big form. The minor of the types 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 zigzag combined, although it is a lot more costly.
These equipments 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 sieves were fabricated in such a way as to allow particles of different size, to pass through the mesh or pores of the sieve plates 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 shoker motor ranges from 0.1000 2.pm (revolution per minute), 0-1200 r.p.m, 0-1500 r.p.m upwards to 2600 r.p.m and are normally used in advanced 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 particles. This is as a result of the losses incurred and the procedures involved, and also the labour needed to clean the sieve plate and to handle the sieve equipment.
The sieve shocker on the other hand is a device used to shake or vibrate a stacked colume of standard sieves and test trays to cause solid particles to sift progressively from the top (with large openings) to the button (with small openings) and a receiver (pan). The sizes of the mesh are in descending order of 17.5mm and 7.3mm, 3.0mm, 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 minute) which does the vibration and causes the shaking of the sieves; a capacitor of 2700 which stores the current; the sieve on/oft 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.