Spray drying involves 3 fundamental processes : liquid atomisation, evaporation and separation/collection of the dried product.
The material to be dried is sprayed, in the form of small droplets, into a vertical drying chamber. At the same time a large volume of hot gas (air) is fed into the chamber to evaporate the liquid content of the sample. Heat and mass transfer takes place as the dispersed droplets are in direct contact with the hot air. On completion of drying, the hot air and solids are separated.
Coarse dried particles may be collected at the base of the drying chamber for further classification and fine particles are separated from the hot air by means of a cyclone separator.
The AL series atomising spray nozzle delivers fine atomisation at low pressures and low flow rates. This is advantageous for abrasive and high viscosity liquids. The internal mix nozzle design provides for the gas (air) and liquid to mix internally in the nozzle. Increases or decreases in the gas pressure can control the droplet size.
The most successful drying applications for spray dryers are for solutions, slurries and pastes which
a) cannot be dewatered mechanically
b) are heat sensitive and cannot be exposed to high temperatures for long periods or
c) contain ultrafine particles that will agglomerate and fuse if dried in any state other than a dilution.
Spray drying is especially applicable to heat sensitive products due to the exceptionally short residence time in the dryer hot zone.
Pharmaceuticals, foodstuffs, pigments and dyes, detergents, urea and plasma are all examples of products that have been successfully spray dried.
CALgrafix Process Monitoring Software – supplied as standard.
CALgrafix is designed for applications where there is a requirement to monitor and record temperature data. A real time graphic presentation displays the temperature profile of your process.
CALgrafix features logging, charting, alarm indication, networking and configuration within a simple WindowsTM based user interface.
Advantages of using CALgrafix :
- Access to detailed process data via the charting and logging features
- Simple set-up, no programming skills required
- Export logged data to other applications
