Abstract
The relation between the heating-radiating characteristics of a far-infrared radiation heateruand the drying characteristics of rough rice was investigated to establish basic data requied for utilization of far-infrared rays for the drying of rough rice. The following results were obtained.
(1) The ratio of radiating energy from the heater to input energy into the heater increases with an increase in surface temperature of the heater.
(2) The total emissivity of the heater is not affected by the surface temperature of the heater.
(3) The far-infrared radiation heater has a higher heating efficiency compared to a sheath heater. However, the thermal radiation is not almost transmitted into solid bodys.
(4) Far-infrared radiation heating is more effective when the distance between heating material and the heat source is shorter.
(5) In heating of rough rice by far-infrared radiation heating, approximately 400[°C] was estimated to be an appropriate surface temperature of the heater as evaluated from the aspects of the monochromatic absorptivity of rough rice and the efficiency of radiating energy from the heat source.
(6) The drying constant of rough rice in far-infrared radiation heating is expressed by the equation of Arrhenius as suggested by existing data on heated-air drying. It was also found that the higher the temperature is, the more the effect of radiation increases and the larger the drying constant of rough rice becomes rapidly.
