DESIGN, FABRICATION AND EVALUATION OF A

RICE THRESHER

BY

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UZATERVER

MATRIC. NO. 2001/11425EA

BEING A FINAL YEAR PROJECT SUBMITTED IN

PARTIAL FULFILLMENT OF THE REQUIREMENT FOR

THE AWARD OF BACHELOR OF ENGINEERING

(B.ENG.) DEGREE IN AGRICULTURAL ENGINEERING

FEDERAL UNIVERSITY OF TECHNOLOGY, MINNA.

NOVEMBER, 2007

DECLARA TTON

I hereby declare that this Project is a record of a research work that was undertaken apd

written by me . It has not been presented before for any degree or diploma or certificate at

any University or Institution. Information derived from personal communications,

published and unpublished work of others were duly referenced in the texts.

iJl ......... fr! ... ................ . Terver Vza Date

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CERTIFICA TION

This project entitled "Design and Fabrication of a Rice Thresher" by UZA TERVER,

meets the regulations governing the award of the degree of Bachelor of Engineering

(B.Eng.) of the Federal University of Technology, Minna, and it is approved for its

contribution to scientific knowledge and literary presentation.

Engr. Dr. O. Chukwu Date

Supervisor

..... (f!j~ ...... ... . . Engr. Dr. (Mrs.) Z.D. Osunde Date

Head, Department of Agricultural Engineering

External Examiner Date

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DEDICATION

This project work is solely dedicated to the Author and Finisher of my Soul Almighty

God and to my beloved parents Prof. & Mrs. Uza also to my mentor, Mr. 1\elson Jpaye.

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ACKNOWLEDGEMENTS

My profound gratitude and appreciation goes first to the Almighty God, the Author

d Finisher of my Soul for his love and for sparing my life till thi s moment. I never knew it

Deep and Sincere appreciation to my ever ready Supervisor, Engr. Dr. O. Chukwu

has been highly efficient and effective in going through my work, providing relevant

aterials and brought about valuable criticism which eventually gave the project the ideal

and also taught me the Use of English , sincerity and hard work.

My gratitude to the I-lead of Department, Engr. Dr. (Mrs.) Z.D. Osunde for her

therly love and concern on the entire department, God bless you.

My appreciation goes to my lecturers in the Agric. Engineering Department; Engr.

Solomon Dauda who despite his tight schedule otTered advice and made available useful

materials for thi s project work, Engr. Peter Adeoye, Prof. Ajisegiri , Mrs. Mustafah, Engr.

Musa. Associate Prof. Alabadan, Engr. Idah , Engr. Fabunmi O.A , Engr. (Mrs.) Bosede and

all members of staff too numerous to mention on this page.

My special appreciation and grat itude goes to my humble parents Prof. & Mrs. D.V

Uza for setting me on the regrettable path of knowledge and for their moral, financial and

spiritual support. I will make you proud!

am greatly indebted to my sib lings, Accountant T. Uza my only and beloved

guemo, Erdoo, Member and Ladi, the best sisters I could ever have, what more

could i have asked for. Thanks for always being there and believing in my strength and for

your moral and financial support. And also to Mr. Nelson lpaye, my mentor and in-law who

has taught me a lot on how to live this life, Thanks for the moral and fin ancinl suppOi'l, wh8l

would i have done without you and also to Engr. Patrick Dalahol , God bless you.

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I want to specially apprec iate Mr. AdRa M88gbc. 01·. Joc Nyngcr and IS8nc Il nelo for

cir moral, financi al and spiritual supporl.

Special thanks to Zaasha, Nicholas, Ajoms, Engr. Tion and Christians around the

Id who despite their busy schedule took out time to pray and stand by the family for the

year.

I must not forget the respective families that we all stand together as one; Nyager's,

zungwe's, Mku's, Maagbe 's, Tor Uja's, Hwande ' s, Okoye's, Anendah's, entire Tar fa mily,

ltodo 's and the entire NKST Family Church.

To the very special ones that stand as a pillar of support that i trul}' call my friend s;

rr. & Mrs. Aondona Orti , Louisa Avishe, Diane, Dami , Douglas, Hemense, Lister, Sesugh

Ajoko, Shadee bobo, Tabex, Amos, Unekwu , the Atini's, UG LI , SO)C, DinllO and /\gric.

Engr. Colleagues; "United we Stand, Divided we Fall ".

wune Ojabo - I believe in you and your dreams. You are my good book and can't get tired

So much Lhanks LO Nathenial Ibrahim who took hi s time in typesetting thi s project work

despite his tight academic schedule, yo u are more than a friend and to Keyus, Jude Okeke

and Ngwongwo - "see things"!

Dooyum Yashi - When it seems the chips are low, yo u bri ghten me up with yo ur in sp iration.

A m proud of yo u!

Big Ups to Yonna, Niro, Rino and Jamdee - we will go places.

Finally to all ARSENAL FANS 'TH E GUNNERS FAMILY'! We got the season!

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ABSTRACT

The rice thresher is a threshing machine that can easily thresh rice from the stalk and to

an extent, clean the rice by removing the sheaves and straw. It is designed and fabricated

to solve threshing problem in Nigeria and minimize cost of purchase of the machine.

Machine threshing cylinder speed of 560rpm shows that, the thresher has a threshing I' j

efficiency of 77.8%, input capacity of 50kg, output capacity of 30kg and a power

requirement of 659.73W. The thresher is efficient with minimal grain loss of 22.2%.

Average grain moisture content (wet basis) was 13.83%. This machine is simple to

operate while maintenance and adjustment reqnires little specialist attention. At high feed .

rate, the machine gets clogged up with chaff, therefore, the machine should be fed with

considerable feed rate; however, machine performance is trouble free at recommended

level of feed rate. It is a threshing machine that can easily thresh rice from the stalk and

to an extent, clean the rice by removing the sheaves and straw.

For effective performance, the power requirement should be above 2hp with a higher

revolution per minute.

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TABLE OF CONTENTS

Title

Declaration

Certification

Dedication

Acknowledgements

Abstract

Table of Contents

List of Tables

List of Figures

List of Plate

Notation

List of Appendix

Chapter One

1.0 Introduction

1.1 Background to the Study

1.2 Harvesting of Rice

1.3 Rice Grain as Food

1.4 Statement of Problem

1.5 Objective of the Study

1.6 Justification of objective

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1

2

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5

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1.7 Scope and Limitation of the Study 5

Chapter Two

2.0 Literature Review 6

2.1 Growing Rice 9

2.2 Rice Production and Uses 11

2.3 Problems and Prospects ofRi~e Production: The Abakaliki View in Focus 13 ,.

2.4 Threshing and Separation ofluce Grain from the Stalk 15

2.4.1 Purpose of Threshing Rice 15

2.5 Threshing Methods 17

2.5.1 Traditional Threshing Methods 18

2.5.2. Mechanized Threshing Methods 18

Chapter Three

3.0 Materials and Methods 19

3.1 Different machine-crop varieties that affect threshing 19

3.2 Determination of physical and engineering properties of rice 21

3.3 Design Approach 22

3.4 Determination of Weight ofUn...;threshed Rice 22

3.5 Motor-Cylinder Design Calculation 24

3.5.1 Angular Velocity of Motor-Cylinder belt 25

3.5.2 Power on Motor-Cylinder Belt 25

3.5.3 Center Distance of Motor-Cylinder-Pulley 26

3.5.4 Angle of Contact of Motor-cylinder pulley 26

3.5.5 Length of Motor-Cylinder Belt 27

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3.6 Cylinder-Fan belt Design 27

3.6.1 Angular Velocity of Cylinder-Fan Pulley 28

3.6.2 Power on Cylinder-Fan Pulley 29

3.6.3 Center Distance of Cylinder-Fan Pulley 29

3.7 Spikes on the Rotating Drum 30

3.8 Power Required to Thresh the Grain in the Threshing Unit 31

3.9 Detennination of Size weld Joining Spikes to the Drum 31

3.10 Selection of Belt for Minor Cylinder Pulley ( . i .

34

3.11 Determination of Weight of Pulley 34

3.12 Detennination of Length of Belt 35

3.13 Detennination of Bending Moment Shear Force and Resultant Bending Moment

of Cylinder Shaft 37

3.14 Detennination of Angle of Twist 46

3.15 Detennination of the Size of Motor 47

3.15.1 Power Required by the Motor 47

3.16 Description and Mode of Operation 48

3.17 Maintenance of the Rice Thresher Machine 49

3.18 Machine Drawings 50

Chapter Four

4.0 Results and Discussions 53

4.1 Summary of the Results of the Fabricated Rice Thresher 54

4.2 Cost Analysis 55

4.2.1 Material Cost 56

42.2 Labour Cost 56

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4.2.3 Overhead Cost

4.3 Economic Analysis of the Rice Thresher

Chapter Five

5.0 Conclusion and Recommendations

5.1 Conclusion

5.2 Recommendations

References

Appendix

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LIST OF TABLES

Table

3.1 Physical and Engineering Properties

4.l Cost of Materials

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Page

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LIST OF FIGURES

Figure Page

3.1 Trapezoidal hopper 22

3.2 Motor Cylinder Pulley-Belt Arrangement 24

3.3 Cylinder Fan Pulley 27

3.4 Spikes on Rotating Drum 30

3.5 Cross Section of V-Groove Belt 34 ( .

3.6 Motor-Cylinder Belt 35

3.7 Cylinder-Fan Belt 36

3.8 Free Body Diagram of Vertical Forces Acting on Cylinder Shaft 37

3.9 Horizontal Shear Force and Bending M9ment Diagram 40

3.10 Bending Moment 43

3.11 Vertical Shear Force 43

3.12 Vertical Bending Moment 43

3.13 Resultant Bending Moment 44

3.14 Horizontal Shear Force 44

3.15 Horizontal Bending Moment 44

3.16 Vertical Bending Moment 45

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Plate .

1.

LIST OF PLATE

picture of the Rice Thresher

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Page

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NOTATIONINOMENCLA TURE

p = density of iron drum

Rm = external radius of the major drum

rm = internal radius of the major drum

Lm = length of the major drum

Lp = length of peg

np = number of pegs

dp = diameter of peg

Lb = length of baffles

bt, = breath of baffles

~ = thickness of baffles

nb = number of baftles

Rn = external radius of minor drum

rn = interdnal radius of minor drum

Ln = length of minor drum

Tt = torgue on threshing cylinder

N = number of revolution per minute

np = number of pegs

F = force acing on threshing drum

0) = angular velocity.

T = resultant torgue

Pt = power required to thresh grain

qy = distribution forces causing deflection

y = deflection of beam

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E = modulus of elasticity

I = second moment of area

D = diameter of peg

FR = peg resultant force

t = throat of weld

x = size of weld

A = throat area

o (max) = maximum stress

V n = volume of major drum

Vp = volume of peg

Vb = volume of baffles

M = mass per unit length

D2 = diameter of drum pulley

V g = gross volume of pulley

Vh = volume of hopper

WD = total weight of drum

g = acceleration due to gravity

w = weight of belt

Vr = volume taken by V-groove belt

Vh = volume of space occupied by cylinder shaft

W p = weight of pulley

L = length of belt

Pu = density of rice

DJ = diameter of cylinder pulley

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r

N J = speed of motor

D2 = diameter of cylinder

N2 = speed of cylinder

C = center to center distance

a = arc of contact

TJ = tension on tight side

T 2 = tensi9n on slack side ,.

G = torsibnal modulus of rigidity

d = diameter of shaft

e = angle of twist

PF = power required to drive suction fan

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Appendix

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LIST OF APPENDIX

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