View of the Half Mini with the new HEPA filter (arrowed)
A new HEPA filter has been developed and is currently available with inlet and outlet connections of either NW50 or NW40. It is recommended for DMA work when operating the sheath gas in closed loop, in order to avoid the survival of any charged or neutral particles in the recirculating sheath gas. The filter can handle sheath air flows of several hundred liters/min with modest pressure drops. The developed filter is relatively inexpensive (therefore allowing cost efficient replacement) and can be inserted in the loop while still permitting the high sheath gas flow rates required to achieve the high resolution offered by SEADM’s DMA.
Replacements for the HEPA cartridge filters are available from SEADM at an inexpensive price. Within the whole measuring chain, the HEPA filter suitably complements the Differential Mobility Analyzer by removing unwanted particles from its recirculation circuit.
The new HEPA filter (detail). Outer diameter is 4″