ABSTRACT

This project (Construction Of A Simple Size Reduction Machine) It was constructed locally with the use of local materials and tools in I.M.T mechanical Engineering workshop.  The various parts of the equipment were constructed separately using mild steel before finally coupled.

During the construction, the conveyors and it’s housing were first constructed.  It consists of a shaft with a helical rod wound round it.  the hopper was measured, out and welded from a mild steel sheet of length 320mm by 60mm with a thickness of 1mm and it has the following dimensions:-

Height of the hopper               –           160mm

Upper part of the hopper        –           140mm diameter

Lower part of the hopper        –           100mm diameter

The conveyor was fixed into it’s housing and welded to the shaft.  The grinding chamber was welded separately and coupled to the grinding discs.  The pressure screw fabricated was welded to the hopper.  The U – channel was joined to the base stand by are welding and the existing setup, the bearing, pulley and the manual handle were all coupled.  It was filed to smoothen the sharp edge and finally painted for corrosion resistance.

After the construction work, test run was carried out using the grains of wet maize and dried maize.  The result shows a greater efficiency in using wet maize.

Also, the high level of noise observed during the test run was reduced by lubricating the essential parts with grease.

TABLE OF CONTENTS

CHAPTER ONE

1.1              INTRODUCTION

1.2              Objective and scope of size reduction equipment.

CHAPTER TWO

LITERATURE REVIEW  

2.1              Origin of size reduction

2.2              Importance of size reduction

2.3              Mechanism of size reduction

2.4              Methods of size reduction

2.5              Classification of size reduction equipment

2.6              Factors to be considered in size reduction equipment

2.7              Behaviour of particles during size reduction

2.8              Theory of crushing

2.9              Factors affecting the nature of materials to be crushed.

CHAPTER THREE

3.1              Selection of material for construction

3.12     Table of summary for the selection of materials and reason

3.2              Construction procedure

3.21          Marking out operators

3.22          Equipment used for marking out

3.3               Cutting operation

3.4              Press size requirements for cutting

3.5              Punching / drilling operation

3.6              Welding joining operation

3.7              Arc welding

3.72          Electrodes used in welding

3.73          Specification of welding electrodes

3.8              Sequence of operation

3.81          The rotating shaft and conveyor housing

3.82          Hopper

3.83          Grinding chamber

3.84          Plate gap and adjustment screw

3.85          Standing

3.86          Driven pulley / prime mover

3.87          Surface finishing and coating 

3.91          Safety of the operation

3.92          Precautions

3.93          Cost evaluation 

CHAPTER FOUR

4.1              Discussion

4.2              Principle of operation

4.3              Precautions

4.4              Maintenance

4.5              Recommendation

4.6              Conclusion

4.7              References

CHAPTER ONE

1.1                   INTRODUCTION

Size reduction in any industry is a very important operation because it involves the breaking down of larges particles by means of mechanical method into smaller and finer size.  It is a major process in some industries like food processing industries, plastic industries, paint and drug industries, ceramic industries, cement industries and groundnut processing industries for effective and efficient and production.

Size reduction which is a unit operation can be defined as an operation whereby bulky solid particles are reduced or broken down into smaller sizes.

Size reduction is also known as comminution (genetic name).  There are different types of size reduction equipment example are crushers and grinders.  Some factors are considered in the selection of these equipment.  The factors are nature of material being handed, feed or particle size, cost of material and construction, size of the product and small power input per unit of product.

In size reduction, different methods are commonly used in breaking down of solids, but only four are commonly used; compression, impact, attrition or rubbing and cutting.

So, for proper involvement of the equipment in the process (its operational capability), care and maintenance is very essential.  Also, safety measures or precautions should be taken when using this equipment.

1.2                   OBJECTIVE / SCOPE OF SIZE REDUCTION EQUIPMENT

Its main objective is to increase the surface area of a given weight of solid.  Other objectives include; increase in reactivity (chemical) of solid, improvement of solvent efficiency, easy handling of materials, for free flow of materials process equipment, permits separation of impurities by mechanical methods and increase the number (numerical strength) of the material.