Basic Principle of Operation

Spray drying transforms a feed liquid into a dry powder in a continuous one step operation

The drying operation consists of three stages:

Atomisation of the feed liquid into a spray by the use of a vaned wheel rotating at high speed

The contacting of the spray with hot air to promote evaporation. The hot air enters the chamber around the atomiser vaned wheel

The separation of dried product from the air in a cyclone

The basic principle involves the atomisation of the feed liquid into a spray of very small droplets there by presenting the feed liquid with a very large surface area enabling evaporation to be completed rapidly. The necessary small droplet sizes are produced by rotating the vaned wheel at high speeds. The resulting evaporation rates are high enough to enable completion of moisture removal from the droplets even though the small chamber volume gives short droplet residence times in the dryer. During the evaporation stage, there is an accompanying cooling effect on the droplets, and with the product residence time in the chamber of short duration, heat damage of the product is prevented