D-R 290

Opacity and dust monitor

Suitability tested and certified optical transmission monitor to measure the opacity or dust concentration in dry flue gas.


  • Continuous and contactless measurement
  • Automatic zero and span check
  • Automatic measurement and correction of contamination of optical surfaces
  • Extremely powerful and stable super-wide band diode (SWBD) light source
  • Extremely low-maintenance
  • Fail-safe shutters with purge air monitoring as option
  • Certified according to EN 15267-3
  • Compliant with US-EPA 40 CFR 60 PS1, PS11, and ASTM D6216 - 12


Measuring principle

The D-R 290 operates using the double-pass method according to the auto-collimation principle. The light beam traverses the measuring path twice. The attenuation of the light beam caused by the dust content in the measuring path is measured and evaluated.

Your benefit

  • Certified for official emission monitoring
    Type approved according to EN 15267-3, compliant with the requirements of US-EPA 40 CFR 60 PS1, PS11, and ASTM D6216 - 12
  • Easy set-up for opacity monitoring
    No gravimetric calibration needed when using transmission principle for reliable opacity monitoring
  • Broad functional range due to dual-path transmission principle
    The sensitivity scales up with growing duct diameter. This allows for measuring very low dust concentrations in very big stack diameters and vice versa very high dust concentrations in small stack diameters
  • Suitable for harsh flue gas conditions
    Non-contact measurement with purge air cushion technology allows for very high flue gas temperatures and aggressive flue gases
  • Durable through options purge air monitoring and fail safe shutter
    Protection of the device through continuously monitored purge air supply and automatic closure of fail safe shutter in case of purge air failure
  • Rugged design for harsh environmental conditions
    Suitable for a wide range of application due to heavy duty metal housing, a broad ambient temperature range and optional versions for EX environments
  • Reliable emission monitoring
    Automatic control functions ensure reliable measuring values


Suitable for dust concentration measurement

  • incineration plants
  • power plants
  • cement plants
  • metal industry
  • plants according to IED 2010/75/EC
  • converter plants and asphalt mixing plants
  • plants for the incineration of biomass


Suitable for measuring the opacity of flue gas

  • plants in accordance with US EPA 40 CFR 60 PS1, PS11 and ASTM D6216 - 12
  • cruise and container ships


Suitable for measurement of dust load in ambient air

  • ware houses
  • storage facilities
  • dust emission monitoring outside industrial buildings

Technical Data

Flue gas typeAir, flue gas, non flammable process gas
Flue gas temperatureAbove dew point up to 250 °C standard,
optional up to 1000 °C
Inner stack/duct pressure (relative to ambient)-50...+20 hPa
Flue gas relative humidity0...95% RF, non-condensing
Stack/duct inner diameter<0.5…18 m (depending on application, flange type and reflector type)
Measuring path length1...18m (depending on application, flange type and reflector type)
Measuring principleMeasuring the optical transmission of visible light which passed a measuring path twice.
ConformitiesIED 2010/75/EU / 17. BImschV
2001/80/EG LCPD / 13. BImschV
27. BImschV
EN 13284-2, EN 14181
EN 15267-3
40 CFR 60 US EPA PS1
40 CFR 60 US EPA PS11
ASTM D6216 - 12
CertificatesCE, QAL1 DIN EN 14181 / DIN EN ISO 14956 / EN 15267-3, MCERTS, Pattern Approval GOST R, Pattern Approval certificate Rep.of Belarus, Pattern Approval Certificate PRC, MCOC 40CFR 60 EPA PS1
Measuring locationIn-situ, non-contact
Self-check, protective functionsAutomatic zero- and span check
Automatic soiling correction
LED light source: no readjustment needed
Automatic fail safe shutter in case of purge air failure (option)
System componentsD-R 290 M xx2 measuring device
D-R 290 R xx2 reflector
D-ISC 100 Universal operating and display unit
D-BL purge air unit
D-R 290 E mounting flange with tube
D-SK fail safe shutter (option)
Physical measuring valueOptical density/ extinction, opacity
Derived measuring valuesTransmission, opacity (SP), extinction, dust concentration in mg/m3, mg/Nm3 (after gravimetric calibration)
Measuring range opacity0...20% ... 0…100%
Output range opacityFreely programmable
Measuring range extinction0…0.1 ... 0...2.0
Output range extinctionFreely programmable within the measuring range
Measuring range dust concentration0…5,000 mg/m3 (depending on calibration and stack conditions)
Output range dust concentrationFreely programmable within the measuring range
Lowest detection limit0.75% for measuring range 0...0.1 extinction
Combined standard uncertainty acc. to QAL1, DIN EN 141811.8%, related to the certified measuring end value 15mg/m3
Light source, spectral range450…680 nm, SWBD LED white
Process connectionConnection flange, bolt circle 100 mm, tube ID = 59 / 83 / 105 mm
Digital interfacesRS 485 Modbus RTU, bi-directional communication
Mini-USB (service)
Analog outputs1x 4-20 mA, 400 Ohm, potential free, assignment programmable
Digital outputs2x contact NC/NO, max. load 60 VDC /
30 VAC / 0.5 A
assignment programmable, typically: maintenance, failure
Power supply24 VDC, 0.5 A
Ambient temperature (operational)-40…+60 °C
IP protection class (IEC 60529)IP65
EX zoneOption: Ex II 3G Ex pz II T4, Ex II 2G Ex px II T4
Dimensions (hxwxd)370 x 190 x 400 mm
Weight10 kg
MaterialAluminum, painted blue RAL 5017
Process connectionConnection flange, bolt circle 100 mm, tube ID = 59 / 83 / 105 mm
Ambient temperature (operational)-40…+60 °C
IP protection class (IEC 60529)IP65
Dimensions (HxWxD)370 x 190 x 270 mm
Weight7 kg
MaterialAluminum, painted blue RAL 5017
Power supply115 / 230 VAC, 50 / 60 Hz (standard)
220-275/380-480V 60 Hz, 3LNPE (option)
Power consumption0.37 kW (50 Hz) / 0.43 kW (60 Hz)
Air supply capacity40 m3/h (50 hPa) / 60 m3/h (25 hPa) (standard)
120 m3/h (25 hPa) (option)
Ambient temperature (operational)-20…+50 °C
IP protection class (IEC 60529)IP55
Dimensions (HxWxD)480 x 450 x 320 mm
Weight12 kg
MaterialStainless steel 1.4301
  • The suitability of the D-R 290 for the listed ranges depends on the kind of dust, the size distribution and the stack/duct diameter.
  • Subject to technical modifications.


Universal display and operating units

The universal operating unit  Opens internal link in new windowD-ISC 100 allows the connection of several DURAG devices. It allows parameterisation and maintenance of all connected devices via integrated keypad or a connected PC and also supports remote access via intranet or internet connection.


Our  Opens internal link in new windowD-ESI Service and Parameterisation Software  assists you to manage all your DURAG sensors connected in one network system via a uniform graphical Interface.


Please contact your sales representitive for more Information.

Supply unit

  • Opens internal link in new window D-TB x00 in various versions
  • for voltage supply of one DURAG sensor
  • different housings available

Please contact your sales representitive for more information.

Purge air blower

  • D-BL xx in various versions
  • for supplying the measuring head with purge air
  • weather protection cover available as an option

Please contact your sales representitive for more information.

We offer various accessories such as weather protection covers for your sensor, reference filter sets, mounting flanges and so on to fit your application and to have all components from one source.

Please contact your sales representative for further information.

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