DESCRIPTION

Sun-drying is a time-tested post-harvesting technology, which is optimally utilized in the Bamboo Solar Drier which solves the problems of humidity and insects and could be easily constructed with locally available materials and skill. 

MATERIALS

Bamboo, rope, 2 metres and 3 metres long black polythene, 3 metres wide and 6 metres long clear polythene and some big stones. 

CONSTRUCTION

Cut 7 pieces of bamboo of the same length (2.5 metres). Cut 2 pieces of bamboo of same length (1.5 metres). Cut a groove 10 cm from each end. (see figure 1). Each groove must be big enough to hold another piece of bamboo. Tie the pieces together to make a frame. (see figure 2). Cut- 10 pieces of split bamboo of the same length (2.5 metres). Lay them flat to make a shelf (as shown in the figure 3). Nail them down at each end. Then, cut 2 metres of black polythene and spread it over the shelf. (see figure 4). Cut 6 metres of clear polythene and put it over the top and down the sides of the frame fold the polythene ends. (see figure 5). 

Pull the polythene across the ends of the frame, as shown in the illustrations, and nail it at both ends and on one side of the frame. The polythene on the other side of the frame should not be nailed down completely so as to leave an opening to keep the food inside the drier. 

Cut a 10 cm diameter hole in the polythene at the top of each end. Put the drier in a sunny place and keep four stones around its base, to keep it steady. Keep the food on a raised drying rack, as shown in the figure 6, and put it inside the dryer. 

WORKING

Cut the fruit into thin slices, after taking the skin off. In case of beans or corn, wash and dry them with a cloth. Peanuts, on the other hand, must be dried in their shells. 

Lay the treated vegetables or fruits on trays and turn them over once a day for proper drying. When the vegetables are dry and hard (after 3 or 4 days depending on the weather), take them out of the drier and pack them in air-right containers. Fruits are generally ready when they are hard on the outside but soft on the inside. Peanuts can take upto 2 weeks to dry. 

ADVANTAGES

1. Drying vegetables: beans, corn, peanuts, pumpkin. 2. Drying fruits: pineapples, bananas ‘khuban’, and apples. 3. Drying fish after it has been salted. 

SOURCE

SPATF, P.O.Box 6937, Boroko, Papua New Guinea