The blower situated on the exhaust side of the dryer operates no negative pressure principle, which creates the induced draught and sucks in the fresh air into the dryer. A stream of hot filtered air is introduced from the bottom of product container containing the wet material. This container is provided with the air distribution plate and Dutch sieve. The air stream is passed through the bed of the material and fluidizes the product particles by creating the turbulence in the product container. Due to fluidization each particle gets surrounded by hot air, which leads quick & uniform heating and drying. Filter bags provided at the top prevent escaping of particles from the machine.
The conventional drying method of drying products in tray dryer is rather inadequate and trouble some. They occupy large floor space, have very high drying times, are labour intensive and offer uneven drying. On contrast Fluid Bed Dryer occupy comparatively lesser floor space, are very easy to operate & can dry material in least time as compared to tray dryer.
In Fluid Bed Dryer, temperature distribution through out the product is uniform and the heat transfer rate is very high. Due to the reduce drying time high production rates are achieved.
As the product is in close contact with drying air at lowtemperature and also for short duration, the physical and chemical properties of the products are generally not effected and therefore the dryer can effectively be used for heat sensitive products. Dueto the continuous movements of product during drying lumpformation, case hardening etc. are minimized.
The Fluid Bed Dryer are most suitable for drying granular, crystalline, coarse or similar material in pharmaceuticals, fine chemicals, dyes, food and allied products. The Fluid Bed Dryer is not suitable for drying liquids or pasty materials.
