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

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%.

Silica GEL Dryer Nafion Dryer

EDM165 & EDM265

Monitor Sample Pipe Dryer Humidity Temperature Sensor Reserve EDM165 main parts

Operating Principle DEHUMIDIFICATION EDM165

Silica GEL Dryer Nafion Dryer

EDM180, EDM365 & EDM565

 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

Dryer flow schematic

Jorge Anjos

Sampling pipe with Nafion tube

RAW Data – 15min average values

RAW Data – comparison to reference daily values