What type of cleaning agent is recommended to be used with the impactor?
The impactor is made of stainless steel, so almost any type of solvent will do. The solvent has to dissolve the measured particles efficiently; for example salts dissolve easily to water, grease to non-polar solvents. The parts should be placed in an ultrasonic bath in the suitable solvent for several minutes. The last wash is recommended to be made with isopropanol, as it eases drying of the parts. If the cleaning is not sufficient the flow rate through the impactor decreases since the particle deposits inside the nozzles in the jet plates obstruct the flow. This can be verified by adjusting 100 mbar below the first stage of the impactor and measuring the ELPI™ inlet sample flow with an external flow meter. If the measured flow rate is much lower that the flow rate mentioned in the calibration data sheet, the cleaning has not been sufficient and another solvents should be tested. The calibrated flow rate is in lpm in the conditions specified in the calibration data sheet.
