Key Benefits

  • We select the best instrument for your application
  • Efficient and effective dust monitoring solutions to help you stay in compliance
  • Robust and reliable instruments

Proven dust monitoring solutions, backed by expertise

If you’re monitoring gaseous emissions, you will likely also be interested in particulates. How much dust is coming out of your stack? What are the characteristics of that dust? Where is it coming from? This is where dust meters come in. Usually supplied as part of a package with the rest of your emissions monitoring solutions, they form an important part of your total environmental picture.

We don’t make dust monitors, which leaves us free to choose the most suitable instrument for your application, taking into account the physical characteristics of your process and the degree of accuracy you require. We primarily use dust and flow monitors from Durag, a German supplier with a long history of success in this field. Durag’s dust monitoring instruments are reliable, robust, easy to operate and to maintain.

Keep dust emissions in check with accurate, reliable measurement

Your application is unique – the evidence for that is in the data collected in your gas analysis system. That’s why we think it makes sense to choose from a wide range of gas analysis solutions. Over the years, we’ve built up a lot of experience in matching the best instruments with every application. Durag’s range of instruments offers solutions for all parameters, including dust concentration, stack dimensions, moisture content, the accuracy you’re looking for, etc.


Measurement Dust/Opacity Dust Dust
Measuring principle Transmission Backward scattering Forward scattering
Durag device  D-R 220  D-R 290  D-R 320  D-R 808
DIN EN 15267-3    ●
US EPA    ●
GOST/EAC   ●  ●
Korean    ●  
In-situ   ●  ●
Automatic zero and control point    ●
Automatic soiling correction    ●
Fail safe shutters    ●  
Range switching    ●  
Remote control unit   ●  ●
Calibratable in  mg/m3wet  mg/m3wet  mg/m3wet  mg/m3wet
Measuring ranges  0-0.2 … 1.6 Ext  0-0.1 … 1.6 Ext
 0-20 … 100%
 0-5 … 200mg/m3  0-7.5 …200 mg/m3
Detection limit @ stack Ø 1 m  20mg/m3  10mg/m3  0,07mg/m3  0.2mg/m3
Detection limit @ stack Ø 5m  8mg/m3  2mg/m3  0,07mg/m3  0.2mg/m3


We generally select from four main Durag dust monitors: the D-R 220, the D-R 290, the D-R 320 and the D-R 808. Each of these is suited to different dust concentrations and measuring lengths. Together, we can choose the system that best suits your application. All of the systems are easy to install, simple to operate and very low maintenance.

A dust monitor for every application

Durag D-R 220 – medium-high range dust monitor

This compact and cost-effective optical dust and opacity monitor provides contactless measurement, making it very low maintenance. The transceiver emits a beam of light from

an LED, which crosses the measuring path twice. The dust weakens the light as it passes through, allowing a measurement to be taken. It’s suitable for short to medium measuring lengths with medium and high dust concentrations.

Durag D-FW 231 – filter monitor

This filter monitor uses the triboelectric effect to determine dust loads in flowing gases. The friction between dust particles creates an electrical charge that is converted into a measuring signal. This signal is proportional to the dust concentration and can be calibrated at a constant gas speed.

This compact system has a rugged design requiring minimal maintenance. It’s ideal for monitoring bag filters, giving you early detection of filter malfunctions, which can result in significant savings.D-FW 231 Filter Monitoring

Durag D-R 290 – opacity/dust monitor

Like the D-R 220, this model is also an optical opacity/dust monitor that uses the double-pass method to achieve contactless measurement with a beam of light. In this model, however, the light source is a super-wide band diode (SWBD), which provides extremely powerful and stable measurement. The D-R 290 has an internal zero and reference point check, as well as contamination measurement. Contamination is automatically compensated. This system has the following approvals:

  • Suitability-tested by TUV
  • Certified according to DIN EN 15267-3
  • Fully compliant with US EPA 40, CFR 60 PS 1 and ASTM 6216D-R 290 Dust Monitoring
Durag D-R 320 – low range dust monitor

This model uses the backscattering principle to monitor even very low concentrations of dust. The modulated light of an LED penetrates the measuring volume in the flue duct and is scattered by the dust particles. A highly sensitive detector records the scattered light, which is directly proportional to the dust concentration.

The measurement takes place continuously in the flue gas stream, giving you a reliable data source that is compliant with the most stringent environmental regulations. The D-R 320 doesn’t require a light trap, making it quick and easy to install. It’s also low-maintenance, and most regular maintenance activities can be carried out without removing the device from the stack.D-R 320 Dust Monitoring

D-R 808 – low range dust monitor
The D-R 808 works according to the principle of forward scattering. The concentrated and modulated light of a laser diode penetrates the measuring volume. The forward-scattered light reflected from dust particles is measured and assessed. Used for monitoring small to medium dust concentrations with a certified range of 0- 7.5 mg/m3, this device is for one-side installation without alignment.D-R 808 Dust Monitoring

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