Aerosol Diluter
ISO 14644-3
VDI 3491
VDI 2083

DIL 550 - Dilution System for Aerosols

The Aerosol Dilution System DIL 550 is designed to accurately dilute aerosols to produce a defined particle concentration for certain measuring tasks. The main application of the dilution system DIL550 is the verification of test aerosols for testing clean rooms. DIN EN ISO 14644-3 defines the necessity of appropriate dilution systems when using test aerosols for verification.
In the applied principle that corresponds to the standard VDI 3491-15, particles are removed from the sample aerosol according to the specified dilution ratio. The particle size distribution remains unchanged.

  • Constant and reproducible aerosol dilution even under changing operation conditions
  • Continuous control and display of actual dilution ratio
  • By default aerosol dilution ratio of 1:100 at 28,3 l/min intake flow rate of a particle counter
  • Number of dilution systems can be cascaded easily to increase the dilution factor
  • Vertical flow duct of aerosol guarantees minimal deposition also for coarse particles
  • Designed for mobile use (no auxiliary pressurized air and additional exhaust needed)
  • Long term lifetime and reliability, minimum maintenance required
  • Precise operation in both over and under pressure mode
  • Modifications to user defined requirements (flow rates, dilution ratio) available
  • In combination with particle counters self-priming system

For higher dilution ratios the diluters of series DIL can be cascaded easily, or alternatively the High Dilution System HDS 561 can be used.

  • Validation of laminar air flow boxes/benches and clean room/environments
  • Evaluation of filtration efficiency
  • Measurement of highly concentrated aerosols
  • Basic aerosol research
  • DEHS aerosol liquid (available in amounts of 80 ml, 0,5 l, 1 l, 5 l or 20 l)
  • Other aerosol liquids on request
  • Device carrying case for one dilution system DIL and one aerosol generator series ATM
Koffer DIL_frei
  • Quick fit tube connector (straight or elbow) (with mounting tool)
  • DDS 560: Dynamic Dilution System for various sample volume flows with adjustable dilution factors (for particle counters with volume flows from 0.3 …3l/min
  • Atomizer Aerosol Generators ATM 210/220/230 suitable for filter tests according to VDI 2083-3 and EN ISO 14644-3


From the aerosol stream to be diluted a sample is taken through a thin capillary. Particle concentration of the capillary flow rate remains unchanged whereas a HEPA filter removes nearly all particles from the bypassing flow rate. After the capillary and filter both streams are mixed together again and the dilution ratio results from the ratio between the two single flow rates.

Optical Particle Counter like LAP 340, have a physical limit up to which concentration they work accurately. Is this concentration exceeded errors will inevitably occur. According to standard VDI 2083 for testing clean rooms and work benches it is compulsory to carry out measurements with increased concentrations in the incoming aerosol. By using the dilutor DIL 550 upstream of a particle counter a dilution factor of up to 100 can be achieved. Thereby particle concentrations of >106 Particles per cf (1cf = 28,3l) can be reduced to 104per cf. This will put the particle concentration well within the range of standard particle counters.

Counter Pressure 5 kPa (50 mbar)
Accuracy of the flow rate ± 5 %
Inlet/Outlet diam. 8mm
HEPA-Filter Filter efficiency 99,97 %
@ 0.3 µm DOP Particle
(ASTM D2986-71)
Minimum lifetime of 500h guaranteed at flow rate of 28 l/min and  2×106 particles/cm3 (<1 µm)
Power Supply 9 … 15 VDC (AC adapter, battery operation)
Dimensions 160 mm x 300 mm x 110 mm
Weight DIL 1.5 kg

An overview of all device versions of series DIL can be found here: Specifications of the series DIL