An aerosol can change due to the dilution and sampling used in the system. Applications under high pressure or high temperature, like in combustion processes, will produce aerosols sensitive to pressure and/or temperature. To reduce the influence the measurement process has on the aerosol, the entire measurement chain has to be configured to provide isobaric and isothermal conditions. The KHG series of dilution systems can be heated up to 200°C for isothermal dilutions and can also be pressure-resistant up to 10 bar overpressure for isobaric dilution. When using the KHG series in combination with the heatable and/or pressure-resistant Welas® or Promo®, aerosol spectrometers, a completely isobaric and isothermal measurement chain is ensured.
The PMPD dilution system is used for aerosol characterization of emissions from internal combustion engines, including continuous combustion cycles. The Particle Measurement Program (PMP) is a mass measuring method in line with standardizing the particle measurement technique for internal combustion exhaust gases. The PMPD dilution system was specifically developed for the PMP application or the PMP measurement chain. The PMPD dilution system consists of a vaporization line and dilution line heated to 200°C and a thermodiluter to remove volatile particles. The efficiency of removing volatile particles was determined to be 0.99967. This was attained in Switzerland at the METAS Institute by means of a thermodiluter up to 200°C with 30 nm sized tetracontane (C40H82) droplets in accordance with "VPR Calibration Procedure AEA / ED47382 / Issue 5″ (Volatile Particle Removal Efficiency).
