The Dynamic Dilution System DDS 560 is designed to definitely and reproducibly dilute aerosols according to EN ISO 14644 part 3 with possibility to adjust the dilution factor. The adjusted dilution factor is shown on a display. In the applied principle that corresponds to the standard VDI 3491-15, particles are removed from the sample according to the specified dilution ratio – the particle size distribution remains unchanged.
Optical particle counters show a maximum measurable aerosol concentration due to their operating principle. If this limit is exceeded major errors cannot be excluded, for example because of coincidence. In case of clean room testing or laminar flow box testing according to VDI 2083 measurements of high upstream concentrations are required. Conventional clean room particle counters are unable to measure at such high concentrations.
By placing the dynamic dilutor DDS 560 before a particle measuring device, e.g. the LAP 322: Laser Aerosol Particle Size Spectrometer, the aerosol concentration can be reduced by a factor selected by the user. Thus, the required upstream concentration can be diluted to a concentration which is within the measuring range of the particle counting device.