1. GRIMM Aerosol Technik Dehumidification methods Dehumidification methods from GRIMM by Eng. Wolfgang Brunnhuber

2. general information  Moisture / humidity is the greatest problem when measuring particles in ambient air.  Most instruments on the market heat the probe up to about 35-40°C to handle this problem. But at the same time they loose the semi volatile compounds (SVC).  We at GRIMM have decided to dry the probe instead of heating to keep the SVC. We begin to dry when humidity gets higher than 65%.

3. Silica GEL Dryer Nafion Dryer

4. EDM165 & EDM265

5. Monitor Sample Pipe Dryer Humidity Temperature Sensor Reserve EDM165 main parts

6. Operating Principle DEHUMIDIFICATION EDM165

7. Silica GEL Dryer Nafion Dryer

8. EDM180, EDM365 & EDM565

9.  Nafion transfers moisture quickly Water transfers through Nafion as a first order kinetic reaction. Water transport is driven by partial vapor pressure differential.  Nafion transfers water selectively Water associates readily with sulfonic acid groups and permeates through the membrane wall.  Nafion needs no maintenance By the working principle of the Nafion it has the big advantage that it doesn’t need any cleaning and has a long life time (if used under normal ambient air conditions over 10years) without loss of performance.  No loss of semi volatile compounds Benefits of Nafion

10. Dryer flow schematic

11. Jorge Anjos

12. Sampling pipe with Nafion tube

13. RAW Data – 15min average values

14. RAW Data – comparison to reference daily values