The aerosolgenerator ATM 225 is applied for the generation of test-aerosoles with defined attributes. The

concentration of aerolsol particles is adjustable. An essential application area of the aerosol generator

ATM 225 is the testing of high-efficiency filters or the acceptance and control measurement of laminar flow

boxes and clean rooms. The determined distribution of the DEHS-Aerosol concentrations shows, that

there is a very high particle concentration (>107

 particles/cm3

) within the range of expected MPPS (most

penetration particles 0.2...0.3µm). In accordance to these measurements many devices for optical particle

counting (> 0.3µm...0.5µm) generate an equal amount of particles (0.5X106

 particles/cm3

) within their

demanded measuring range. A high consistency of the different particle concentrations as well as of the

particle distribution is guaranteed because of the used constructive and technological solutions in the

aerosolgenerator. Therefore the generated aerosol is very well reproduceable.

The aerosol generator ATM 225 is characterized by a compact and sturdy construction and is easy to

handle. Higher security demands are considered by using a protective low voltage (12 V/DC) for the

power supply. The aerosol substance is in a glass container, which is protected from external influences at

the top by means of an opening swing-hood. The smooth surface of the ATM 225 is easy to clean and to

desinfect. The small device size as well as the slight weight are good prerequisites for a mobile and

flexible application. The essence of the ATM 225 is a new atomizer, which is completely made of highgrade

steel. The atomizer works according to the injector principle and is a bimaterial nozzle, which is

coupled with an impact separator. The function of the impact separator is to lead back the large generated

drops immediately after the nozzle propulsive process. In addition to that task the generated particle size

distribution is defined. The necessary compressed air for the nozzle propulsive process is generated by

means of a calm working piston compressor. The compressed air is cleaned with a HEPA-filter before

entering the atomizer. The standard volume power is determined up to 250 l/h.

Determination of the particle generation rate

The generated aerosole concentration can eligibly be determined at the ATM 225. For this task the ATM

225 has a needle valve at the sucking side of the device, which is combined with an indicator instrument

flow controler. When the (needle valve) Nadelventils is closed the total volume power is lowered, too and

by that the particle generation rate of the atomizer was shifted. Low volume power sucks less fluid for the

jetting process and therefore the particle generation rate is lowered.