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close this bookComparative Study of Solar and Sun Drying of Fish in Ecuator (NRI)
close this folderSection 1 - Equipment and methods
View the document(introduction...)
View the documentSolar dryers
View the documentSun-drying methods
View the documentFish preparation
View the documentOperating procedure
View the documentFinal product analysis

Operating procedure

As can be seen from Plate 1, Appendix 6, the rocks, the rack and the three solar dryers were closely grouped in an open sunny aspect. Care was taken in positioning the dryers to prevent any of the taller dryers throwing shade upon another. A series of plates of the dryers is given in Appendix 6.

Over the four-week period of operation the fish were placed in the dryers in the morning (07.30 - 07.45) and removed in the early evening (17.15 - 17.30). Approximately 8 kg of prepared fish could be accommodated in each of the solar dryers; this loading was maintained during ail the drying experiments. The fish were turned regularly, twice a day, to ensure even drying. At night, the fish were press piled in plastic bins which were kept in a store. When it rained, the fish on the rocks and on the rack were covered with plastic sheets.

Measurements were taken at hourly intervals of the following: insolation using a solarimeter and integrator (Lintronic Ltd, 54 - 58 Bartholomew Close, London, EC1A 7HB), ambient and internal dryer temperatures with a temperature recorder (Grant Instruments (Cambridge) Ltd, Barrington, Cambridge, Cambridgeshire), ambient humidity with a whirling hygrometer (C. F. Casella and Co. Ltd, Regent House, Britannia Walk, London, N1 7ND) and wind speed using an anemometer (C. F. Casella and Co. Ltd).* Each batch of fish was weighed at intervals of three hours during the day. When successive weighings indicated little or no change in weight, the fish were considered effectively dry and were removed from the dryers, allowed to cool, and held in plastic bags in the store. During the course of an experiment, a record was kept on the condition of the fish as they dried.

Adjustment to, and control of, the dryers was deliberately kept to a minimum to simulate their operation by a busy fisherman. Action to control the temperatures within the dryers was minimal. Vents and openings were closed in the early morning and late afternoon in order to raise internal temperatures as quickly as possible and maintain them as long as possible, and reasonable care was taken during the hottest periods of the day to prevent the internal temperatures exceeding 55 - 60°C due to the risk of either case-hardening or cooking occurring.