Comde-Derenda GmbH

Automatic Sampling System PNS T-DM

Design The system consists of the following principal components: • Stainless steel cabinet with two lockable doors • Control unit with electronic modules, SD card reader and RS-232 interface • Rotary-vane vacuum pump • Orifice plate • Temperature and humidity sensor • Filter changer unit with Geneva drive • 3 filter magazines for 18 resp. 24 filters each • Aluminum intake tube (anodized, polished inside, diameter Ø 40 mm, length 800 mm, custom lengths available) • Sampling inlet (for particulate matter fractions PM10, PM2.5, PM1 or TSP; optional) • Peltier cooler (optional) • GPRS modem (optional) Type 3.1 is equipped with a 4 m³/h pump. The volumetric flow rate for sampling PM10or PM2.5 fractions is 2.3 m³/h; the maximum vacuum at the filter is 300 mbar. The maximum volumetric flow rate when using glass fiber filters is 3.5 m³/h. Type 6.1 is equipped with an 8 m³/h pump and can be operated with a maximum volumetric flow rate of approx. 5.5 m³/h. It is especially suitable for measuring semi-volatile organic compounds (SVOCs) and for use in conjunction with special filter materials (e.g. cellulose nitrate or Nucleopores filters). The maximum vacuum at the filter is 500 mbar. The system cabinet is vented in order to prevent moisture condensation and icing. The connection between the sampling inlet and intake tube is gas-tight. Three magazines and 36 resp. 48 filter cartridges come with each unit. When magazines are changed, one filter cartridge remains in the sampling position. The 18th resp. 24th filter is used not for sampling but as a reference filter to collect possible passive particle deposits. The magazines also serve as portable containers. Operating Principle Before sampling begins, the desired settings are entered in the control unit, and the filter magazines are placed into the filter changer. Once the operating cycle is activated, sampling takes place automatically according to the set parameters. During operation, the vacuum pump draws in air laden with fine particulate matter through the sampling inlet, where the desired fraction is separated. The particles of the desired fraction are then deposited on the sampling filter in the sampling position.