Development and performance evaluation of a tomato grading machine

Abstract

Grading fruits and vegetables is a valuable activity affecting quality, and handling can store the product for future use and plays a major role in the food processing industries. In Bangladesh, tomato grading is done manually when needed. Manual grading is a labor intensive and inefficient process. Therefore, this study involves the design and fabrication of a low-cost tomato grading machine so that they can grade tomatoes easily, faster, and effectively instead of manual grading. The proposed grader consisted of different units such as lifting system, conveyor system, grading unit, collector and electric motor. The lifting system consisted of some tools such as bearing, chain, conveyor mat, and gear (sprocket type). The trays were used to collect the graded tomatoes which were made of MS sheets and covered with soft foam to prevent the tomatoes from damaging. With the help of chain and gear, power was transmitted from one grading chamber to the corresponding grading chamber. It also helped to operate the lifting system and gave rotary motion to the particular grading chamber. An AC electric motor was set which helps to operate the machine with a controlled speed without any obstruction. The total fabrication cost of the tomato grader machine was US$ 273.33. The grading capacity of the machine was found 540 kg hr^-1 and the damage percentage was found on average 1.5%. The average grading efficiency of the machine was 76%. The grading cost per kg was US$ 0.0026.