Monitors total VOCs in Ambient Air
Over the years complex organic compounds have got into use in many diverse applications encompassing all types of human activities. While rural environments often have high levels of pesticides and other residues from sprays of weedicides and other chemicals used in modern farming, urban environments have high doses of a host of organics coming from paints & varnishes, lacquers, solvents, foam blowing agents, sprays etc.
Unfortunately a majority of these compounds are highly toxic and many of them have been reported to be carcinogenic. Recent addition of Benzene in petrol, in place of a lead compound, has made Benzene and its derivatives a part of vehicular pollution. Benzene concentrations in high traffic areas and near petrol pumps have become a matter of concern.
Organic compounds are also reported to be pre-cursers for Ozone formation and play a role in secondary formation of oxidants. All over the world air pollution monitoring networks are making intensive efforts for monitoring of specific organic compounds such as Benzene, Toluene & Xylene and other Hydrocarbons.
In India the Central Pollution Controlled Board (CPCB) has included Benzene as a parameter in Ambient Air Quality Standards revised in 2010. The method for measurement of Benzene requires Gas Chromatographic (GC) Analysis with two possible approaches: a) An air sample collected in the field in a Tedlar bag can be directly fed to a GC or b) VOCs are collected from ambient air by adsorption on a suitable collection matrix such as activated charcoal and desorbed for analysis via a GC.Both techniques require the use of a battery operated / portable instrument capable of drawing air at a low flow rate of a few mili-liters per minute.
Envirotech has developed the APM 802 Volatile Organic Compounds (VOC) Sampler to facilitate collection of such samples. Envirotech has been manufacturing the APM 856 Organic Vapour Sampler for past many years. The APM 802 has evolved from the experiences gained and the feedback received from the users of the APM 856.
The APM 802 VOC Sampler can be used to collect air samples in Tedlar Bags. Alternatively an adsorption tube may be connected at the suction port to trap VOCs present in ambient air. The APM 802 uses a digital flow-meter to accurately measure low flow rates in the range of 10 to 500 ml/min. Very low flow rates coupled with its feature of collecting a composite sample allows the user to collect a representative sample over several hours without fear of sample loss due to saturation or breakthrough in the adsorbing column. The Envirotech APM 802 is a battery operated instrument. After an over night charge the system will operate for a full 8 hour shift allowing comparison with TLV limits for toxic organics present in Indoor Environments.
- Portable, battery operated low flow, pump.
- Oil-free pump has low noise and requires little maintenance.
- Digital Flow Meter provides accurate flow reading in the 20-500 ml/min flow range.
- Built-in Flow Totalizer directly indicates the volume of air sampled in liters.
- Programmable Microcontroller based timer allows operation in cyclic manner for collection of composite samples.
- Same hardware can be used for monitoring a wide variety of organic compounds.
- Rechargeable Li-ion battery pack allows operation for at least 8 hours after overnight charging.
Flow Rate Range
20 to 500 ml/min.
LCD 16 characters, 4 line display. The instrument constantly displays flow rate and total volume of air sampled
Continuous and compositing. In continuous mode air sample is collected continuously at a flow rate set by the user. In Compositing Mode, the pump is operated as per programmable ON & OFF cycle. So a composited sample consisting of small spaced out samples is automatically collected. The instrument displays and records the total volume of air sampled.
The APM 802 VOC Sampler is provided with a re-chargeable Li-ion battery pack. The instrument will operate for 10 hours in continuous mode and 24 hours in compositing mode with a fully charged battery. A built-in battery status facility allows the user to check useable battery life and automatically prompts the user when the battery is running low. To prevent battery damage the instrument will automatically shut-down when the battery voltage drops to a pre-set level.
Continuously adjustable with a precision needle valve.
In built digital timer can be programmed to Start / Stop pump operation at a pre-set time.
Elapsed Time Indicator
Sample operation period in minutes displayed on LCD.
Choice of Sampling Media
The APM 802 sampler allows the user to use adsorbing media such as charcoal tubes or collect a filtered air sample in Tedlar Bags. A Filter holder designed for 25mm diameter filters is provided with the system.
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