Design, fabrication and testing of a hand operated vegetable grinding machine

Abstract

Vegetables are increasingly proving to be essential for nutrition and food security as they provide adequate amounts of micronutrients and non-nutrient compounds for humans. They also provide a promising economic opportunity for reducing rural poverty and unemployment in developing economies. Dried vegetables and their application in powder form is gaining interest in the food industry as ingredients, also used as intermediate products in the beverage industry, used in perfumery and cosmetics as well as resources for nutraceutical. Traditionally, grinding of dried vegetables is done using pestles and mortars which requires a lot of effort leading to limited production capacities and poor quality of produce. Also small vegetable grinding machines exist but there is need to make available grinding machines that have low production costs. To ensure that they are readily available and affordable for local vegetable powder producers, a hand operated vegetable grinding machine was designed and fabricated. The materials used in the fabrication of the machine are sourced locally so as to ensure that it is cheap, affordable and easily maintained by the small scale processors and house hold families. The machine consists of the frame, crank handle, feed hopper, grinding chamber, conveying chamber, grinding discs, and the adjusting screw system. Tests were carried out to investigate the performance of the machine on the basis of grinding rate, efficiency and quality of the product produced. The grinding capacities of the machine obtained were 4.47 kg/hr, 4.65 kg/hr and 4.8 kg/hr for Gobe, Nakati and Ddodo respectively. The machine efficiencies were 84.75%, 85% and 84.25% for Gobe, Nakati and Ddodo respectively. The hand operated vegetable grinding machine is cheap, durable and cost of operation is low and could be used by household families and small scale processors.