The dilution of large droplets is particularly important when measuring highly concentrated droplet aerosols. Since large droplets are difficult to dilute, standard systems only work up to a size of 1 - 2 μm

Problem of existing dilution systems:

• Large droplets (above 3-5 µm) are destroyed
• Change of the dilution ration in regards to the particle size

According to this Problem it is very difficult to get a good correlation between the optical measured mass and the gravimetrical evaluated mass with a droplet aerosol, e.g. in the crankcase ventilation filter testing.

The target for the development of the new dilution system LDD was to dilute large droplets with practically no losses to get a better correlation between the optical measurement and the gravimetrical result. To prevents condensation, the model variant LDD 100 H can be heated up to 120 °C.

The newly developed dilution system LDD 100 H (dilution factor 100) is the first system to dilute almost loss-free large droplets up to 10 μm. The good dilution ratio was proven with monodisperse DEHS oil droplets of different sizes. The results of 5 µm & 7 µm are...