SAMPLE STREAM DRYER
SAMPLE STREAM DRYER
Drying the aerosol sample stream is highly recommended to provide accurate measurement data and to protect equipment from water condensation.
In hot, humid locations, the water vapor content of the ambient sample air may be very large. This can lead to inaccuracies in aerosol analysis such as the BC measurement – but, more seriously, there is the possibility of water condensation inside analytical instruments which can lead to permanent damage. This issue is solved by the use of our Sample Stream Dryer.
The interaction of water with aerosol species changes their physical properties. Consequently, the World Meteorological Organization has recommended that all aerosol measurements should be performed under conditions where the Relative Humidity is 40% or lower (WMO/GAW 2003; Wiedensohler, 2014).
Many stations in hot, humid locations have air-conditioned interiors. If the indoor air-conditioning temperature Ta is comparable to or lower than the dewpoint (condensation temperature) Td of the outside ambient air, water will condense in the tubing and inside the instrument. This will not only completely in-validate the data, but it can also cause permanent damage to the instrument.
The Magee Scientific Sample Stream Dryer removes water vapor from the inlet flow by means of a semi-permeable Nafion membrane. This membrane selectively absorbs molecules of water vapor from the air-stream and passes them to a space on the other side of the membrane, maintained at a low absolute pressure by means of a vacuum pump.
The Magee Scientific Sample Stream Dryer can reduce the dew point temperature by up to 14 degrees Celsius at a flow rate of 5 LPM. The equipment is self-contained, automatic, and includes a display screen which shows the input and output hygrometric properties. A data cable can connect to the Model AE33 Aethalometer so that the temperature and humidity data are incorporated into the Aethalometer’s data files.
The Magee Scientific Sample Stream Dryer can be used to remove water vapor from the inlet stream to any aerosol instrument, not just an Aethalometer.
- Nafion® membrane technology
- Sample flow rate to 5 LPM
- Excellent drying efficiency – up to 14°C decrease of dew point
- Extremely low particle loss – < 4 %
- 100% compatible with AE33 Aethalometer®
- Fully functional as stand-alone device
- Ambient Air Quality monitoring in humid locations
- Laboratory aerosol studies
- Direct combustion emissions measurement
- Low temperature sampling (drying does not affect volatiles)
- USB powered ; 5 V ; 200 mA
- Chassis material: Aluminum
- Length: 82 cm / Diameter: 11 cm
- Weight: 4.55 kg
ENVIRONMENTAL OPERATING CONDITIONS
- Indoor use only
- Temperature range: 10 – 40 °C; Temperature measurement accuracy: 0.2 °C
- Relative humidity range: non-condensing; Relative humidity measurement accuracy: 2%;
- Drying efficiency: 14 °C @ input dew point temperature 22 °C
- Particle loss: < 4 %
- Sampling air: inlet / outlet type – 1⁄4” NTPF
- Purge air, vacuum pump connection: 1/8” NTPF
- Sample air flow: up to 5lpm; Purge air flow: 4 LPM
- Drying pressure: -700 mBar
- USB Type B (for power supply only)
- RS232 serial interface for data transmission
- Chassis functional grounding
- Display: 4 x 20 alphanumeric character display
- LED indicator: Green, Yellow, Red
- Vacuum gauge / Vacuum adjusting control
EXTERNAL PUMP SPECIFICATION
- (KNF) N838.1.2.KN.18 230V/50 Hz
- (KNF) N838.1.2.KN.18 115V/60 Hz
- Delivery: 37 LPM free air: (5 LPM at vacuum 300 mbar abs.)
- Vacuum: 100 mbar abs
- Dimensions: 402x121x110 mm
- Weight: 6.8 kg
GENERAL QUESTIONS ON SAMPLE STREAM DRYER
WHY SHOULD WE USE THE SAMPLE STREAM DRYER?
Using a dryer when analyzing atmospheric aerosols is recommended by world Meteorological Organization Global Atmosphere Watch as a routine part of air quality monitoring. Aerosol physical and optical properties may change in humid environments – but, more seriously, there is the possibility of water condensation inside the instrument which can lead to permanent damage. Many stations in hot, humid locations have air-conditioned interiors. If the indoor air-conditioning temperature Ta is comparable to or lower than the dewpoint (condensation temperature) Td of the outside ambient air, water will condense in the tubing and inside the instrument. This will not only completely in-validate the data, but it can also cause permanent damage to the instrument.
CAN WE USE THE SAMPLE STREAM DRYER FOR OTHER AEROSOL INSTRUMENTS ALSO?
Yes! You can even connect a data logger to the Dryer, to record the properties of the sample air stream.
ARE THERE SIGNIFICANT PARTICLE LOSSES IN THE DRYER?
Particle loss has been extensively studied and measured at less than 4 %. The Nafion membrane is selective for water vapor and does not affect any of the aerosol particles’ physical properties.
WHAT IS THE DRYING EFFICIENCY OF THE SYSTEM?
The Dryer performance depends on the actual Ta and ‘dewpoint’ (condensation, Td) temperature of the inlet air. For example: when the input dewpoint temperature is 22 °C, the Dryer will reduce the dewpoint by 14 °C at a sample flow rate of 5 LPM. At lower flow rates, the reduction in dewpoint is greater. The psychrometric performance data are shown as a function of inlet humidity in the Dryer user’s manual.
IS IT POSSIBLE TO CONNECT THE DATA FROM THE DRYER TO OTHER DEVICES?
Yes! You can connect the Dryer to an external datalogger or PC with an RS232 serial communication port.
WHERE CAN WE USE THE DRYER?
The Sample Stream Dryer can be used for all aerosol particle measurements. It can be used for ambient air quality monitoring in humid locations, aerosol studies in laboratories, direct combustion emissions measurements, or any situation where water vapor must be removed from the sample stream.
Sample Stream Dryer software – latest release and other important documents
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