Chamber design is dictated by the type of atomisation, a disc requires a wider diameter of chamber to allow material to shear from the disc horizontally while the Tall Form chamber is narrower and long, both systems have the same volume of chamber for a given throughput. The shape of the chamber can has a big impact on strength, wider body chambers are in general substantially weaker than Tall Form Chambers for a given volume, a mild steel frame is often used on disc dryers to increase chamber strength.
The mild steel frame employed on wide body chambers is covered with cladding. Long term the use of differential metals is a factor in chamber cracking.
At European SprayDry chamber design is the heart of the drying system, chambers are manufactured from thick gauge materials giving a greater explosion retention capacity and longer life.
Co-Current chambers are most common form of chamber employed in production plants producing the majority of products on the market. Co-Current can dry heat sensitive powders more effectively because the drying air has been cooled by evaporation before the dry powder temperature can increase.
In the Co-Current dryer hot air is introduced through the top of the chamber and is drawn out of the bottom of the chamber. Feed is introduced into the hot air zone at the top of the chamber, the effect of the atomisation reduces the heat dramatically as the heat energy is used in the evaporation of moisture.
The powder then falls to the base of the chamber where it is extracted along with the air. There are several variations of the Co-Current chamber design, some allow for the removal of the exhaust gasses and fines from either the top of the chamber or from a bustle ring between the cylindrical section and the cone known as the bustle.