Improved design and fabrication of a sunflower threshing machine.

Abstract

Sunflower (Helianthus annuus L.) are commonly used to extract oil for consumption. Certain varieties of sunflower seeds are used in confectionery and are called confectionery sunflower seeds. They are also used as snack foods. The traditional threshing process is time and labor consuming. Hence an improved sunflower threshing machine was developed and evaluated. Different components of the machine were designed basing on the physical, mechanical and chemical properties of sunflower, the components include, the feed hopper, beaters, sieve, frame, shaft, threshing unit analyzing the forces acting on the components to prevent failure. The machine uses 3hp motor. In Uganda, 30 percent of small scale farmers grow sunflower (Towo & Mugisha, 2013) but use rudimentary methods of threshing i.e. the sunflower is dislodged from the pods by stick beating. However, this method is time consuming and leads to the production of poor-quality seeds; where some seeds are broken, some are not completely removed from the sun flower beads, contaminated with soil as the threshing is done on a bare ground. The production of broken seeds affects agriculture since. they are not -viable and difficult to store for long period of time thus posing a potential threat of food insecurity. The already existing sunflower threshing machines have low threshing efficiency of and are also sophisticated (UK Sunflower Association, 2003). Hence the need for designing and fabricating a sunflower threshing machine. The methods used for assembly were machining, welding, milling, drilling, cutting and gridding. The machine uses a maximum power of 3 hp motor. After fabrication the performance and economic analysis was performed in terms of threshing efficiency, cleaning efficiency. The total cost of the machine is Ugx 1.2m. Owing to the performance and economic evaluation of the machine it achieves. all its design. purposes hence its recommended for commercialization and adoption by the target group.