D-R 220

Dust and opacity monitor

Compact and cost effective transmittance dust and opacity measuring device for monitoring medium to high dust concentrations in dry flue and process gas.


  • Non-contact measuring method
  • Continuous measurement of opacity and dust concentration
  • Suitable for medium or high dust concentrations on short to medium measuring lengths
  • Automatic internal self-test, zero point and reference point check
  • Manual contamination and linearity check
  • Extremely low-maintenance due to self-test functions and LED source
  • Easy installation and commissioning with universal operating unit and adjustment tool
  • Convenient operation including remote access capability
  • Cost-effective, small measuring system
  • Operation with or without control unit

Your benefit

  • Easy set-up for opacity monitoring
    No gravimetric calibration needed when using transmission principle for reliable opacity monitoring
  • Compact and cost effective solution
    The smallest available DURAG dust monitor comes with an attractive system pricing
  • 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
  • Designed for a wide range of environmental conditions
    Corrosion-free plastic housing and a broad ambient temperature range
  • Reliable emission monitoring
    Automatic control functions ensure reliable measuring values


Suitable for dust concentration and opacity measurement

  • Measurements with variable flow speeds
  • Visibility Monitoring


  • Power industry
  • Biomass incineration
  • Waste incineration
  • Cement industry
  • Crematories
  • Process monitoring

Opacity measurements on ships

  • Ro-Ro ships
  • Cruise ships
  • Container ships

Also suitable for

  • Cost effective process monitoring
  • Filter monitoring
  • Measurement of ambient air dust-load in halls or warehouses

Technical Data

Flue gas typeAir, flue gas, non flammable process gas
Flue gas temperatureAbove due point,
≤ 200 °C standard,
up to 500 °C option
Inner stack/duct pressure (relative to ambient pressure)-50 … +10 hPa standard,
-50 … +50 hPa option
Flue gas relative humidity0 … 95 % RH, non-condensing
Stack/duct inner diameter0.4 … 10 m
Measuring principleMeasuring the optical transmission of visible light which passed a measuring path twice
CertificatesCE, Pattern Approval Certificate PRC
Measuring locationIn-situ, non-contact. Mounted at stack, measurement across the stack, purged sensors are not in contact with flue gas
Self-check, protective functionsLED light source: no readjustment needed
Automatic internal self-test
Automatic zero and reference point check (option)
Manual contamination check and linearity check (option)
System componentsD-R 220 M measuring device
D-R 220 R reflector
D-R 220 SPF purge flange
D-R 220 CLP clamping ring fastener
D-R 220 N zero point reflector (option)
D-R 220 E adjusting flange with tube (option)
D-ISC 100 universal operating unit (option)
Purge air and power supply unit (option)
Physical measuring valueTransmission, opacity
Derived measuring valuesOpacity (PLC), optical density, dust concentration in mg/m3, mg/Nm3 (after gravimetric calibration), extinction coefficient, visibility
Measuring range transmission100 … 0%
Output range transmissionFreely programmable
Measuring range opacity0 … 100%
Output range opacityFreely programmable
Measuring range extinction0 … 1.6
Output range extinctionFreely programmable
Measuring range dust concentration0 … 5000 mg/m3 (depending on calibration)
Output range dust concentrationFreely programmable
Lowest detection limit0.2 % transmission
Combined standard uncertainty acc. to QAL1, DIN EN 14181less than 0.013 Ext (2 mg/m3 for particle size 1 … 2µm, duct ID 5m (16.4 ft))
Light sourceLED
Process connectionAdjusting flange, bolt circle 100 mm, tube ID = 59 / 83 / 105 mm
Purge air connectionFor hose Ø 25 mm
Electrical connectionDURAG standard device connector M23 male
Digital interfacesRS 485 Modbus RTU, bi-directional communication, USB (Service)
Analog outputs1 x 4 … 20mA, 400 Ohm, isolated, assignment parameterisable
Digital outputs2 x contact NO, permissible load 60 VDC / 30 VAC / 0.5 A,
function can be assigned. Typically: maintenance, failure
Power supplySensor supply voltage 24 VDC, 0.4 A
Ambient temperature (operational)-20 … +50 °C
IP protection class (IEC 60529)IP65
Dimensions (HxWxD)150 x 132 x 214 mm (150 x 132 x 331 mm with purge air flange)
Weight2.7 kg
MaterialHousing: Polyamide, RAL 5017, fire class B1 (UL 94 V0),
Purge air flange: 1.4571 (316 Ti)
Process connectionAdjusting flange, bolt circle 100 mm, tube ID = 59 / 83 / 105 mm
Ambient temperature (operational)-20 … +50 °C
IP protection class (IEC 60529)IP65
Dimensions (HxWxD)126 x 132 x 101 mm (126 x 132 x 218 mm with purge air flange)
Weight1.6 kg
MaterialHousing: Polyamide, RAL 5017, fire class B1 (UL 94 V0),
Purge air flange: 1.4571 (316 Ti)
Usage withD-R 220 M: 24 VDC, purge air supply
D-R 220 R: purge air supply
Power supply90 ... 264 VAC, 48 ... 62 Hz
Air supply capacityStage 1: max. 15.5 m3/h
Stage 2: max. 31 m3/h
IP protection class (IEC 60529)IP65
Dimensions (HxWxD)410 x 400 x 200 mm
Weight10 kg
MaterialStainless steel 1.4301 (AISI 304)
  • The suitability of the D-R 220 for the listed ranges depends on the kind of dust, the size distribution and the 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
  • version with integrated purge air blower 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.