Development, Fabrication And Performance Evaluation Of A Single Wheel Driven Boom Sprayer

CHAPTER THREE
3.0    Materials and methods
3.1    Factors to be considered in the selection of materials for the fabrication
I.    Strength of the materials: The materials used for the fabrication of the single wheel driven boom sprayer must be able to resist the externally applied forces without breaking or yielding. This internal resistance offered by a part to an externally applied force is called stress.
II.    Cost of the materials:  The materials used for the fabrication should be low in relative to price. The materials are cheap and readily affordable for farmers who have interest in designing the machine.
III.    Availability of materials:  The materials used for the fabrication must be readily available and locally sourced around the environment of the workshop. The materials should be available in handy to the workshop where the fabrication was done.   
IV.     Durability of materials: The materials selected for the fabrication of machine must be able to resist wear, decay and must be able to last long. The materials selected must have strong endurance ability.
3.2    Design consideration
             The following are the design consideration for the single wheel driven boom sprayer
I.    Power requirement; The single wheel driven boom sprayer is a small hand propelled vehicle with just one wheel. It was designed to be pushed and guided by a single person using two handles at the rear.
II.    Weight of the machine: The single wheel single boom sprayer was designed to distribute  the weight of its load between the wheel and the operator so enabling the convenient carriage of the tank than would be possible were the load carried by the operator. As such it is a second class lever. It has a central wheel supporting the whole load.
III.    Speed of operation; Since it will be operated by a single person, it depends on tthe pace of individual operator.
IV.    Boom height: This impacts the efficacy of the application by affecting the uniformity of the spray along the length of the boom. The effect of drift is related to exposure of the spray droplets to the wind. It should be light in weight and easy to operate.                                           
V.    The machine should be simple in construction
VI.    It should be easy to repair and maintain
VII.    It should be light in weight and easy to operate
VIII.    It should be suitable in  operation by a person.
IX.    Distance between nozzles to nozzle should be considered
X.    Size of nozzle should be considered
XI.    Different parts of the machine should be simple as possible so that it can be made in local workshop.                                                       
3.3    Design and Development of Various components of the machine
3.3.1    Knapsack sprayer
    A knapsack sprayer of 16 lit capacities with 340 x 190mm dimensions was selected. The tank is made up of plastic. A frame stand was fabricated on the machine with 380 ×225mm dimension suitable for the tank to fix in the place.   

3.3.2   The frame                                                Angle iron rod of 2 inches was used for the fabrication of the frame. The fabrication was carried out at the department Agricultural and Bio-environmental Engineering department workshop. The materials and tools used include the following 
I.    Measuring tape : for taking measurements
II.    Tri square: for checking angles
III.    Hacksaw: for cutting iron rod 
IV.    Vice: for holding the piece
V.    Electric hand grinder: for leveling cuts
VI.    Welding machine: for joining parts
VII.    Electrode: used with joining machine for joining parts