Development of a Portable Screening Machine for Cowpeas and Lentils

This paper presents the design and fabrication of a portable machine aimed at improving the efficiency of screening cowpeas and lentils for impurities such as stones and chaff. The project addresses the challenges faced by Nigerian consumers and retailers who traditionally screen beans by hand; a laborious and time-consuming process. The machine's design leverages on a pneumatic system to separate impurities based on density differences, ensuring a compact and quiet operation suitable for household use. The study includes a literature review of existing methods, system design, materials selection, and detailed fabrication steps. Computer-aided design of the developed machine was carried out followed by the assembly of the assembled parts. The time taken for screening increases linearly with the quantity of cowpeas to be screened. Performance assessment was conducted through testing and evaluation, focusing on the machine's efficiency in separating stones from cowpeas. The results obtained indicated that the flow rate of cowpeas was 2.5868 g/s. while the time taken to screen 1g of cowpeas was 0.387 s. The paper concludes with recommendations for further improvement, aiming to enhance the quality and safety of beans consumed and to encourage higher consumption due to the convenience provided by the machine.