Design, Fabrication and Performance Evaluation of Pedal Operated Groundnut Decorticator

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Shelling of groundnut pods (Arachis hypegea) by hand is tedious, laborious and unhygienic with low efficiencies. As a result farmer get low income due to amount of broken kernels and a lot of time is lost in the tedious shelling operation. To overcome this problem, pertinent parameters that influence shelling efficiency of pedal operated groundnut decorticator were identified. Pedal operated decorticator were designed and fabricated with chain and sprocket of bicycle and aluminum spike tooth is used and evaluation was done in the department of Agricultural and Bio-Environmental Engineering Technology, Kwara State Polytechnic, Ilorin because it was affordable and locally fabricated. A rotary motion mechanism was employed to drive the decorticating drum while concave screen was fixed. The selection of the screen aperture was based on the size and shape of the groundnut seed. The factors considered in this project work were feed rate and operators characteristics (height, weight and knuckle lengths). The evaluation of machine was conducted while time was taken for each tests. The result of the pedal operated groundnut decorticator revealed that operator III has the maximum shelling efficiency of 65% was achieved at 9minutes, 16 seconds and breakage of 9% and throughput capacity of 15.3kg/hr. Operator II was the optimum shelling efficiency of 56% at 12 minutes 44 seconds and breakage of 8% and throughput capacity of 14kg/hr. Operator I has the minimum shelling efficiency of 47% at 11 minutes 44 seconds and breakage of 16% and throughput capacity of 15kg/hr. The total amount used for the fabrication of the pedal operated groundnut decorticator was totaled to Ninety-two Thousand and Seven Hundred Naira only (N92,700.00). The result of the fabricator implies that the characteristics of Operator III is recommended to farmers who shell for seed can now obtained more seed shelled with low breakage and will get more income.


Cover Page                                                                                                                          i

Title Page                                                                                                                           ii

Certification  iii

Dedication  iv

Acknowledgements  v

Abstract vi

Table of Contents  vii

List of Tables  xi

List of Figures  xii

List of Plates  xiii


1.1           Background to the Study  1

1.2           Statement of the Problems  2

1.3           Objective of the Project 2

1.4           Justification of the Project 3

1.5           Scope of the Study  3


2.1           Physical Properties of Groundnut 4

2.1.1       Determination of Size  4

2.1.2       Determination of Coefficient of Friction  5

2.1.3       Determination of Moisture Content 5

2.1.4       Angle of Repose  6

2.1.5       Porosity  6

2.1.6       Surface Area  6

2.2           History of Groundnut in Nigeria  6

2.3           Agronomy of Groundnut 7

2.4           Post Harvest Losses of Groundnut Seeds  8

2.5           Economic Importance of Groundnut Seed  9

2.6           Factor Affecting Shelling Operation  11

2.6.1       Cylinder-Concave Clearance  11

2.6.2       Sieve Shake  12

2.7           Description of some Threshing Equipment 12

2.7.1       Maize Sheller 12

2.7.2       Maize Dehusker-cum Sheller: 13

2.7.3:    Hand Maize Sheller 13

2.7.4      Groundnut Striper 14

2.7.5:   Groundnut Thresher 15

2.7.6:   Groundnut Decorticator Manually Operated  16

2.7.7      Power Operated Groundnut Decorticator 17

2.7.8      Pedal Operated Thresher (Paddy Thresher): 18

2.8           Terminology Related to Thresher 18

2.8.1       Feed Rate  18

2.8.2       Clean Grain  19

2.8.3       Concave Clearance  19

2.8.4       Cleaning Efficiency  19

2.8.5       Threshing Efficiency  19

2.9     Review of Existing work  19


3.1           Physical Properties of Biological Materials  23

3.1.1       Sample Preparation  23

3.1.2       Determination of Size and Shape  24

3.1.3       Determination of Moisture Content 24

3.1.4       Determination of Mass, Volume and Density  25

3.1.5       Determination of Coefficient of Static Friction  25

3.1.6       Determination of Angle of Repose  25

3.2           Description of the Groundnut Pedal Operated Machine  26

3.3           Design Consideration  28

3.4           Design Calculation and Analysis  28

3.4.1       Design for Hopper 28

3.4.2.     Design for Decorticating Unit 29

3.4.3       Design of Chain Drive  32   Determination of Chain Length between the Pedal and Idler Shaft 32   Determination of Chain Length Between the Idler Shaft and Decorticating Shaft 33   Determination of Chain Length Between the Idler Shaft and Blower Shaft 33

3.5           Material Selection  34

3.6           Fabrication Procedure and Assembly  34

3.6.1       Fabrication of Main Frame  34

3.6.2       Fabrication of Hopper 35

3.6.3       Fabrication of Bicycle Pedal and Chain Drive  35

3.6.4       Fabrication of Decorticating Drum   35

3.6.5       Decorticating Screen  35

3.6.6       Operator Seat 36

3.6.7       Aluminum Spike Tooth  36

3.7           Principle of Operation of the Machine  36

3.8           Cost Analysis  37

3.9           Performance Evaluation  38

3.9.1       Sourcing of Experimental Material 38

3.9.2       Sample Preparation  38

3.9.3       Experimental Procedure  38

3.9.4       Instrumentation Used for the Experiment 39

3.9.5       Design Layout 42

3.9.6       Output Parameter 42


4.0           Results And Discussion  45

4.1           Results  45

4.2.          Discussion  46

4.2.1       Physical Properties of Groundnut Pods  46

4.2.2       Effect of Operator Parameter Threshing Efficiency  47


5.1           Conclusions  48

5.2           Recommendations  48

References  49

Appendix A   52

Appendix B   59

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Frontiers, E. & A., B (2022). Design, Fabrication and Performance Evaluation of Pedal Operated Groundnut Decorticator. Afribary. Retrieved from

MLA 8th

Frontiers, Edu, and BOLADALE A. "Design, Fabrication and Performance Evaluation of Pedal Operated Groundnut Decorticator" Afribary. Afribary, 08 Jan. 2022, Accessed 24 Jan. 2022.


Frontiers, Edu, and BOLADALE A. . "Design, Fabrication and Performance Evaluation of Pedal Operated Groundnut Decorticator". Afribary, Afribary, 08 Jan. 2022. Web. 24 Jan. 2022. < >.


Frontiers, Edu and A., BOLADALE . "Design, Fabrication and Performance Evaluation of Pedal Operated Groundnut Decorticator" Afribary (2022). Accessed January 24, 2022.