IJSRP, Volume 7, Issue 1, January 2017 Edition [ISSN 2250-3153]
AbeyrathnaR.M.R.D., Amaratunga K.S.P., Kariyawasam H.K.P.P.
A far infrared continuous type rice flour gelatinizer was developed and tested. At presentrice flour is roasted in batch process using electricity or firewood in industry. The existing batch type conduction heating roasters are labor intensive and energy inefficient. Radiation heating is more effective compared to conduction and convection in food processing.At present, there are no far infrared heating continuous type rice flour roasters for industrial use. An auger was used to mix and move flour in the machine. At the top and the bottom of the auger, far infrared heaters were established to supply radiation heat. The industrial requirement was to get gelatinized rice flour at the rate of 300kg/h. To achieve required rpm, heater height and temperature and retention time were considered.Driving mechanism was developed to rotatethe auger at 28 rpm. Control system was developed using 16F684 microprocessor to control the heaters’ temperature and auger by modulating pulse width to achieve the maximum gelatinization of rice flour while maintaining the required output. One thermocouple and three LM35 sensors were used to automate the system. Styrofoam and wood boards were used to insulate the machine.Rice flour was added from the rice mill at a rate of 300kg/h to the gelatinizer.Maximum input flour temperature from the mill was 75°C and output temperature from the gelatinizer was 90°C. Machine’s inner surface temperature was maintained at 100°C. Outer surface temperature was 66°C. Moisture content at the output was 11.30% wet basis and viscosity was 350Mpa/s.Machine power consumption was 4.8kW/h. Moisture was removed at a rate of 0.24 L/h.