Design of Melon De-husking and Separation Machine
Chapter One
OBJECTIVE OF THE STUDY
(i) The objective of this project is to design, fabricate and test a melon de-husking and separation machine in order to increase productivity in melon processing and reduce human labour of manual de-husking and separation to the bearest minimum.
(ii) This project will improve the living standard of million of rural dweller who may engage in melon processing.
(iii) It will encourage the growth of small and medium scale industrial enterprise in the agric – processing nation wide.
(iv) This project will contribute to the overall economic development of the nation by encouraging indigenous engineers technologists and technicians in designing, fabricating and testing of processing machines.
CHAPTER TWO
REVIEW OF SOME PROPERTIES OF MELON SEED/METHODS OF DE-HUSKING
NUTRITIVE CONTENT OF MELON
MANUAL DE-HUSKING
Manual de-husking methods can also be categorized in two ways namely singular and batch methods.
SINGULAR METHOD OF MANUAL DE-HUSKING
In this method, treated melons are picked one after the other with hand and a twisting force is applied to each of the melon with two hands thereby breaking and separating the shell from the white seed. This old method is usually used in homes in the rural areas by women and children. The method is labour intensive, time consuming and productivity in de-husking is drastically low.
MANUAL BATCH METHOD OF DE-HUSKING
In this method, treated melons are put in a sack or bag, and light impact forces are applied manually to the sack with a flat stick continuously at different points on the sack. Visual observation is used from time to time to determine maturity in de-husking. When fully de-husked, the content of the bag is removed, separation and sorting.
Another way applying the impact force on the bag or sack is to continuously hit the sack on a hard wall at different points. This manual batch method has a lot of disadvantages namely:.
- It is labour intensive
- Percentage breakage of melon is very high
- Productivity in de-husking and separation is low
- De-husking and sorting time is very high.
MECHANISED METHOD OF DE-HUSKING
Two method of mechanized methods are in use namely:
- Impact force method and
- Attrition (friction) method
CHAPTER THREE
MECHANICS OF OPERATION OF MELON DE-HUSKING AND SEPARATION MACHINE
The mechanics of operation of this machine is purely based on the dynamics and static of the machine components. The machine components are shaft, bearings, structural stand etc.
Circular motion of some components, gravitational motion of melon to be de-husked from the hopper to de-husking point, aberrational motion of the melon on the wall of the casing and air motion are applied to achieve material flow, de-husking regulatory feed of materials, discharge of de-husked melon separation of de-husked shell from the white seed.
CIRCULAR MOTION AND CENTRIFUGAL FORCE (FC)
The circular motion from the prime mover (electric motor) shaft is transmitted to the output shaft.
For any object of mass M moving in a circular motion, its acceleration is directed toward the centre of the body and its linear velocity is tangential to the radius of the objective.
CHAPTER FOUR
DESIGN CALCULATIONS OF MELON DE-HUSKING AND SEPARATION MACHINE:
The design calculations of this machine is based on the design drawing.
OPTIMAL DE-HUSKING SPEED
The optimal de-husking speed of this machine is found from experimentation to be 900 rpm. Based on this, the shelling impeller is constructed to rotate on 900 rpm.
CHAPTER FIVE
MANUFACTURING PROCESSES FOR THE MELON DE-HUSKING AND SEPARATION
The components of the machine include the following:
- Structural stand
- De-husking impeller
- Blower impeller
- De-husking casing
- Blower casing
- De-husking casing cover
- Blower casing cover
- Chequer linings
- Air blades
- De-husking blades
- Inlet hopper
- Melon exit channel
- Air flow channel
- Electric motor
- Electric motor sitting
- Adapter
- Bolts and nuts
CHAPTER SIX
CONCLUSION
The aim of this project which is to design and fabricate a machine for shelling melon has been achieved with outstanding performance.
It has a shelling efficiency of about 80% and is quite satisfactory in terms of reliability, maintainable, cost and simplicity of the manufacture compactness and portability. It stands to serve both homes and small scale industrialist.
However, the machine is completely a new design and as such may require an improvement in the general outlook.
RECOMMENDATION
The design and the mathematical analysis of the machine is based on the material selection and spinning disc shaft design
In such case, the constructions and recommendation must be strictly adhered to in all operation.
Finally, we recommend that galvanized steel should be used for the construction of the shelling chamber, if machine should be of highly commercialized purpose.
REFERENCES
- A.O Falusi &I.O.A Adeleye (1988), Agricultural Science for Senior Secondary school
- Emeka Iwenofu (1997) Design of melon de-hustling and separation machine
- John Haman & Stephen R.C. (1984): Mechanics of machines
- J.G Douglas, J.M & J.A. Gasiorek (1995), Fluid Mechanics. ELBS/ Longman
- Edward Shigley & Charles .R. Mischake Hill. (1989): Mechanical Engineering Design McGraw
