unit sizes to Technical specifications continu B2-VH-17-D Bevel-helical gear units B2

Flender/Flender Gear Units/Bevel-helical gear units B2

lunkhe (, forcedconvectiontype dryer was successfully used for grape drying from 7% to 5% moisture 6 Grabowski et al. Fig. 2 Examples of large-scale solar dryers: () Australian type dryer. (From Ref. 3.) () Plastic- tent solar dryer. (From Ref. 3.) content (wet basis) within 2 days, and to less than 1% in 6 days. This is considerable improvement when compared to 8 days for regular sun drying of oleate-sprayed grapes,or more than 2 weeks regular sun drying of untreated grapes. The authors indicated thatthis type of dryer has an added advantage over sun drying for raisins, .., protecting thefruit from inclement rains as well as insects. Another solution in this type of installations is the use of very long metal air preheater pipes ( or large-surface solar collectors (. The ow of air is then articial with the use of powerful fans. In the construction designpresented in Ref. 4, the length of the solar air preheating pipe was about 7 miles. Theheating rate of this preheater was reported to be sufcient for proper operation of solar-assisted sonic dryer for several fruits and vegetables. 3.1.3 Solar-Assisted Articial Dryers For commercial applications, in which large tonnage of product needs to be dried, some source of auxiliary energy is needed to initiate forced air movement and/or to providethe supplemental energy. In this scenario, the solar drying equipment is part of wholedrying system and generally assists operation of typical air dryer, supplying it someamount of heat. Construction of solar-assisted articial drying system can be simple or Drying of Fruits, Vegetables, and Spices 6 Fig. 3 Low-cost fruit and vegetable solar dryers. (Courtesy of Brace Research Institute, McGill University, Montreal, Canada.) 6 Grabowski et al. combined with other elements, such as source of stored heat or heat pumps. In the simplest system the solar energy is used directly to provide part of the heat requiredfor moisture evaporation in conventional air dryer. The dryi