DEVELOPMENT OF A SMALL SCALE WASHING MACHINE FOR ROOT CROPS

A small scale washing machine with a rotating drum and a continuous pressurized water stream was developed and evaluated for root crops washing at farm after harvesting process. The performance of the developed washing machine was evaluated in potato tubers washing under three different drum speeds of 10, 20 and 30 rpm, three different batch loads of 12, 24 and 36 kg and four different retention times of 2, 4 ,6 and 8 min. Results revealed that the proper washing performance in terms of washing efficiency (93.07%), bruising percentage (5.33 %) and microbial washing efficiency (85.8 %) was achieved when the machine was operated at 20 rpm rotor drum speed, 36 kg batch load and 4 min retention time. At such proper operating parameters, the machine productivity was 0.43 Mg/h and the consumed specific energy was 3.96 kWh/Mg. To promote the developed washing prototype in small farms implementations, the potato washer production cost was estimated by 6.25 USD/Mg (100 EGP/Mg), which was less about 2.8 times than that of the manual washing process of 17.37 USD / Mg (278 EGP / Mg).