Central Potato Research Station, Jalandhar, 144 003, (Punjab).
A prototype of rubber rollers type of potato grader has been designed and developed. It consists of main frame, grading rollers, conveyor belt and power transmission systems. Hollow rubber rollers resembling the shape of a tambourine/reel and having square hole (21 mm diameter) in the centre, mounted on steel shafts (21 mm square) constitute the grading mechanism of this prototype. Power transmission system of the grader includes a 2HP electric motor and a reduction gear box with speed ratio of 15:1. Six categories of grades, viz. less than 10gm 10–25g, 50–75g, 75–100g and more than 100g can be obtained with this grader with almost negligible bruising. More than 6000 kg of potatoes can be graded in an hour when the speed of conveyor belt was 14 m/min and roller revolve at 83 rpm. Twelve persons were engaged for feeding and moving the gunny bags filled with graded tubers.
