DESIGN AND FABRICATION OF A PORTABLE CASSAVA GRATER

ABSTRACT

There is need for a hygienic processing of cassava. Prevalent condition in the commercial grating area of this staple food shows a susceptibility of food contamination. This project addresses the need for the development of a home scale cassava grater where the materials, the tuber s of cassava being grated can be properly monitored.

Some design considerations used in this project are; the machine should be efficient during use in the household as well as moveable (portable) and Safety or easily operated. Another problem considerations is that cassava Produces a large amount of cyanogenic glycosides so in selecting materials, for construction adequate care must be taken not to use materials that cannot degrade /corrode easily due to the acidic content in cassava. The malice component which is made from mild steel which consist of major parts namely, the mainframe which is constructed with angle iron which gives strength and rigidity  o the war all matins, the hopper/s receptacle through which cassava is admitted into the machine for grating, the grating unit consist of the shaft, perforated  mesh  rolled sheet, circular disc and rival pins, the discharge unit   which direct the flow of the grated cassava to astrrage   pit or receptacle, and the electric  motor which is made from cast iron and winding horse power of the machine . The capacity of the grater fabricated was 158kg/hr. the unit cost is #62,100 as against the #75,000 for the current grating unit in the market.

TABLE OF CONTENTS

Title Page i

Certification ii

Dedication iii

Acknowledgement iv

Abstract v

Table of Contents vi

List of Table x

List of Figures xii

CHAPTER ONE: INTRODUCTION

1.0 Introduction 1

1.1Varieties of Cassava 1

1.2 Importance of Cassava 2

1.3 Uses of Cassava 3

1.4 Methods of peeling Cassava 4

1.4.1 Manual Method 5

1.4.2 Chemical Method 5

1.4.3 Steaming Method 6

1.4.4 Mechanical Method 6

1.5 Justification of the Study 7

1.6 Aim and Objectives 8

1.6.1 Objective 8

1.7 Scope of study 8

CHAPTER TWO: LITERATURE REVIEW

2.0 Literature Review 10

2.1 Background to the study 10

2.2 Economic Importance of cassava product 14

2.3 Steps or Procedures for Cassava Processing 15

2.3.1 Peeling 16

2.3.2 Washing 17

2.3.3 Grating 17

2.3.4 Dewatering/Dehydration 18

2.3.5 Fermentation 18

2.3.6 Frying 18

2.3.7 Sieving 19

2.4 Types of Cassava 19

2.4.1 Manual Grater 20

2.4.2 Mechanical Grater 21

2.5 Factors Affecting Grating Performance 23

2.5.1 Capacity of Grater 23

2.5.2 The Rate of Grating 23

2.5.3 Rough of the Grater Surface 24

2.5.4 Moisture of Cassava Tuber 24

CHAPTER THREE: MATERIALS AND METHODS 

3.0  MATERIALS AND METHOD 26

3.1  Materials 26

3.1.1 Mild Steel 26

3.1.2 Stainless Steel 27

3.1.3 Alloy Rubber 28

3.1.4 Cast Iron 29

3.2  Description of Machine Parts                                                                      31

3.2.1  The Main Frame                                                                                       31

3.2.2 The Hopper 31

3.2.3 The Grating Unit 31

3.2.4 Electric Motor and Pulley System 32

3.2.5 The Discharge Unit 32

3.3 Project Methodology 32

3.3.1 Machineries and Machining Processes 32

CHAPTER FOUR: 

DESCRIPTION OF THE MACHINE AND ITS MAJOR COMPONENTS

4.0  Description of The Machine and its Major Components 35

4.1  Cassava Grating Drawing           35

4.2  Shaft Design 40

4.3  Determination of the Bending Moment of each point of loading 41

4.3.1 Force Exerted on Shaft 42

4.3.2 Reactions at the Bearings due to Vertical Loading 44

4.3.3 Reactions at the Bearings due to Horizontal Loading 46

4.3.4 Speed Transmission 48

4.3.5 Power Transmission 49

4.3.6 Belt Design 50

4.3.7 Determine of Centre Distance 50

4.3.8 Length of Belt 51

4.3.9 Angle of Contact on Driver Belt Sheave 51

4.4 Performance Evaluation 52

CHAPTER FIVE: 

5.0 CONCLUSION AND RECOMMENDATION                                       58

5.1 Conclusion 58

5.2 Recommendation 58

References 60