Development of an Economical Automatic Temperature and Time Control Multipurpose Dryer

Many dryers exist in the open markets for drying several agricultural crops in Africa. Most of them
have their limitations and complexities. The significant ones are expensive and cannot be afford by
the peasant farmers. Those developed locally are inefficient especially where temperature control is
required. There is need to develop appropriate systems that will ensure effective temperature control
without compromising the quality parameters of products. Time control is also a challenge due to
unstable power supply which result to calculation of drying time not the same as working hours of the
dryer for existing dryers. A digital microprocessor base temperature control and time control dryer has
been developed and fabricated for drying any type of biomaterial at varying temperature range using
locally available materials. The fabricated temperature and time control multipurpose dryer was test to
ascertain its performance, the preset temperature control the ON/OFF the heating helix in the drying
chamber within room temperature to 110°C and the temperature control was compared with three
different types of digital temperature meters. The time control was also tested to clock only when the
dryer is powered. Some selected biomaterial (Cassava, maize, cocoyam) with moisture content
between 13 - 26% MCwb was dried for an average time of about 6-8 hours at 60°c temperature and
the air velocity of the drying process was 0.4-0.75 m/s2.