Cassava is produced in a large quantity in Nigeria. One of the products emerging
from its processing has turned out to be a major staple food in the nation, which is ‘garri’.
Due to insufficient and inadequate processing equipment; cassava has been susceptible to
wastage and ‘garri’ production has been reduced in scale, thereby resulting in
insufficiency and high cost of ’garri’ in the market. In order to ease the production
process, a compact mechanized cassava mash/‘garri’ sifter was designed and constructed
with a speed of 290rpm and power requirement of 1hp to tackle some of the major
problems encountered in ‘garri, production. The machine does not only granulate and sift
cassava mash into fine grits for easy frying; it also sieves dry ‘garri’ into fine, even and
edible particles; it is also capable of re-granulating dry coarse grain of ‘garri’ back into
the regular sizes; of which the earlier machines made could not combine these three
operations. The machine has an average capacity of 10.52kg/hr. for combined grating and
sieving operations and 22.5kg/hr. for ordinary sieving operation. The efficiency of the
machine for grating and sieving operations lies between 84 and 87% while the weight
loss efficiency is between 86 and 99% for all operations. The machine is useful for small,
medium and large scale industries; the initial and operating cost is affordable for both
domestic and commercial ‘garri’ producers. The machine can be run with either an
electric motor or a mechanical prime mover, particularly in the rural areas where there is
no electricity supply. The machine can be easily operated by all genders; however
children and infants should be restricted from using the machine. The capacity of the
machine can also be increased with an increase in size of the machine.
TABLE OF CONTENTS
ABSTRACT ii
TABLE OF CONTENTS iii
LIST OF TABLES x
LIST OF FIGURES xi
CHAPTER ONE: INTRODUCTION 1
1.1 General Introduction 1
1.2 Economic Importance 3
1.3 Problem Identification 4
1.4 Objectives 5
1.5 Project Justification 5
CHAPTER TWO: LITERATURE REVIEW 6
2.1 History of Cassava Production in West Africa 6
2.2 Garri Production from Cassava 7
2.3 Sifting of Cassava Mash and Garri 12
2.4 Traditional Methods of Sieving Cassava mash and Garri 14
2.4.1 Hand Held sieve 14
2.4.2 Wooden Column Sieve 15
2.5 Mechanized Method of Sifting Cassava Mash and Garri 16
2.5.1 Use of Mechanized Grater 17
2.5.2 Mechanical Sieve Shaker 17
2.5.3 Mechanized Cassava Mash Sifter 18
2.5.4 Mechanized Garri Sifter 19
2.6 Cassava Lump Sieving Machine Designed and Fabricated at the University of
Ilorin 20
2.7 The New Cassava Mash/ Garri Sifter 22
CHAPTER THREE: METHODOLOGY AND DESIGN OF MACHINE ELEMENTS 23
3.1 Description of the Machine 23
3.2 Principle of Operation 24
3.3 Design Consideration and Material Selection 32
3.4 Design Calculations 32
3.41 Volume of Hopper 33
3.4.2 Mass of Grating Chamber 35
3.4.3 Mass of Sifting chamber 37
3.4.4 Force Required to Drive both Chambers 39
3.4.5 Pulley Speed for both Chambers 41
3.4.6 Power Required by Machine 42
3.4.7 Power Required by the Electric Motor 42
3.4.8 Belt Design 43
3.4.9 Shaft Design 44
3.5 Machine Elements 45
3.6 Fabrication Process and Techniques 48
CHAPTER FOUR: RESULTS AND DISCUSSION 49
4.1 Testing of Machine 49
4.1.1 Moisture Content of Cassava Mash 49
4.1.2 Grating Efficiency 50
4.1.3 Sieving Efficiency 51
4.1.4 Weight Loss Efficiency 52
4.1.5 Capacity of Machine 53
4.2 Results of the Evaluation Process 53
4.3 Discussion 55
4.4 Cost Analysis 56
CHAPTER FIVE: CONCLUSION AND RECCOMMENDATIONS 61
5.1 Conclusion 61
5.2 Suggested Recommendations 61
REFERENCES 63
