{"Page URL":"https://www.appropedia.org/DRYTRAY","Page description":"[[DRYTRAY]]\n1 Figure 1: Basic parts and Air flow pattern in ITDG-Dryer TRAY DRYERS Introduction A range of technologies are used for food drying which include tray and tunnel dryers, spray, roller and freeze dryers. With the exception of tray dryers none of these are appropriate, in terms of cost and output, for use by small and medium enterprises. While sun drying on trays or in solar dryers can be considered as tray drying the term is normally applied to small industrial systems with some form of air heater and a fan to pass air over the product being dried. While small tray dryers are available from Europe and the USA, where they are used in pilot plants and Universities, their cost (in excess of 25,000) makes them unaffordable and un-economic for producers in developing countries. In the early 1980s ITDG recognised the need for small, controllable, powered tray dryers capable of producing high quality products that could be constructed by engineers in developing countries to a great extent from locally available materials. The required basic development work was carried out and there are now tray dryers, based on the principles developed by ITDG, in some eight countries. The greatest up-take of the technology has been in Latin America where probably over 100 units are now operational. The key point to bear in mind when considering the local construction of such a dryer is to understand the basic principles involved and adapt them to local conditions such as the dimensions of local plywood sheet, common stock steel sizes, social conditions and fuel availability. The Tray Dryer Family At the present time ITDG is able to supply information to allow the construction of four types of dryer. In some cases full drawings and a How to Construct and Use manual are available together with a case study book and videos. Much of this information is in English and Spanish. Basic Principles The dryers consist of a cabinet containing trays which is connected to a source of air heated by gas, diesel or bio- mass such as rice husk. The air temperature is usually controlled by a thermostat which is normally set between 50 and 70","Page language":"en","Page license":"CC-BY-SA-3.0","Page title":"DRYTRAY","Page views":"43","Page year":"Monday, 01-Jan-07 00:00:00 UTC","Modification date":"Friday, 28-Nov-25 12:43:35 UTC"}