Sampling Systems / Aerosol Substances / Dryer

DDU 570 - Diffusion Dryer

The Topas Diffusion Dryer DDU 570 has been developed mainly as additional equipment for the Aerosol Generator ATM 220 that is operated by compressed air.
The aerosol to be dried is streaming through 3 screen pipes which are surrounded by Silica Gel (desiccant with indicator) serving as drying agent. The Silica Gel causes a very dry atmosphere. The excess moisture in the aerosol moves into the dry environment by the effect of diffusion.
Because the aerosol does not get into direct contact with the drying agent only a very low particle loss occurs.

  • Only minimal particle loss, because the desiccant and the aerosol are not in direct contact
  • Uncomplicated, but effective working principle (diffusion drying)
  • Desiccant by means of an exsikkator easy to regenerate

The diffusion dryer was developed for applications under ambient air pressure condition. It is not suitable for pressure conditions.

Physical Data of the Silica Gel *)

Colour Orange
Smell Odourless
Bulk density approx. 800 kg/m³
Granular size Granules / 2 – 5 mm
Loss on drying (150°C, 3 h) max. 2%
Water adsorbing capacity min. 25%
Colour change from orange to colourless
Melting Point >1000 °C
Flash Point Not applicable
Substances to be avoided strong oxidizing agent

*) contains heavy metal free moisture indicator
Versions of diffusion dryer

DDU 570/H DDU 570/L
Adapted for: ATM 230 ATM 220 / ATM 226
Dimensions in mm
(Ø x height)
70 mm x 475 mm 70 mm x 253 mm
Mass of drying agent approx. 830 g approx. 410 g
Max. volume flow 10 l/min 5 l/min
max. pressure counter 100 mbar
max. ambient temperature 40 °C
max. aerosol temperature 40 °C
Hose connector 8 mm
Weight (without silica gel) 0.94 kg 0.72 kg