Dryers, belt chamber

Active Dry Yeast (ADY). The production of active dry yeast is very similar to the production of compressed yeast. However, a different strain of yeast is used and the nitrogen content is reduced to 7% of soHds compared with 8—9% for compressed yeast. The press cake made with the active dry yeast strain is extmded through a perforated plate in the form of thin strands with a diameter of 2—3 mm and a length of 3—10 mm. The strands are dried on endless belts of steel mesh in drying chambers (a continuous process) or in roto-louvre dryers (a batch process), with the temperature kept below 40°C. Drying time in drying chambers is 3—4 h and in roto-louvre dryers is 6 h or more. The final moisture level attained is 7.5—8%. 

In larger factories the fruit is steamed on the shelves of chamber dryers or on the belt of belt dryers. 

Adding a moving belt dryer at the bottom of the drying chamber applied for materials that are extremely difficult to dry by spray drying. 

For conveyor dryers, the wet feed is carried on a belt or a vibrating conveyor that is made to pass slowly through a heating chamber. Depending upon the design, hot air may or may not pass through the bed of solids on the conveyor. 

The belt dryer used as the second-stage dryer offers longer exposure time to much lower air temperatures needed to complete the drying process. In this primary drying chamber, the semidried product with internal moisture collects on a continuously moving belt made of a woven polyester filament and... 

---