Enquiry:hkmarketing@epc.com.hk 
Process description
The liquid to be dried is pumped to the top of the drying chamber by a variable-speed progressing cavity pump, which provides a very smooth flow and constant flow rate. It is atomised by a two-fluid nozzle and enters the drying chamber as a fine droplet dispersion.
Hot air is blown into the chamber, on to the droplets causing flash evaporation of the surface moisture.
The bound moisture in the particles is evaporated in the time that they fall to the discharge point at the base of the cone (the residence time). In this configuration the particle temperature will never exceed the wet bulb temperature of the exhaust air.
A variable-speed centrifugal fan provides control over the inlet air flow and a steady inlet temperature is achieved by using a three-term controller in conjunction with an electric heater. A second variable- speed fan draws air from the chamber through a cyclone separator. This ‘push-pull’ fan system provides flexibility to operate the chamber at variable pressures with variable residence times.
Two powder collection points are provided, one at the bottom of the main chamber, and one on the cyclone separator. This enables particles of different sizes to be collected simultaneously and/or separately.
Exhaust-air relative humidity can be measured and controlled so as to enable the system to run at the required RH level.
The nozzle is an external-mix two-fluid atomising nozzle. Compressed air is directed onto the liquid stream as it leaves the nozzle body and immediately atomises it. With this type of nozzle the orifice is larger than a single fluid type, and so it is possible to atomise more viscous products and even products containing suspended solids.
Features / benefits
No clogging, no need for de-blocking devices
Co-current flow for drying heat sensitive products
Counter-current flow maximises chamber residence time for non-heat sensitive products
Residence times in the drying cylinder variable up to 9 seconds u Data recording to computer for rapid evaluation and comparison u Accessory sets are available to quickly change from drying to spray chilling
Drying air temperature up to 250°C
Maximum flow rate up to 7 l/hr
Maximum evaporation rate of 3 l/hr
Tall form chamber straight side to diameter ratio of 3:1 conical discharge section
Advanced two-fluid nozzle atomisation system
Individual inlet and exhaust fans with variable-speed control
Bag filter and trace heating options
Flexible controls and full instrumentation provided in the IP65 control console
Easily dismantled for inspection and cleaning purposes
Compact, mobile design
Data logging facility for all key operating parameters
Powder discharges from two points, chamber and cyclone
Low noise levels
Control and measurement of relative humidity
Spark arrester on input and enhanced safety extraction fan
