Durag D-R 320 Dust Monitor

The DURAG D-R 320 is a scattered light dust monitor that detects the lowest to medium dust concentrations in dry flue and process gas.

The D-R 320 is based on the back-scattered light principle – the light of a red laser diode illuminates the dust particles in the measuring volume of the flue gas duct. The light scattered backward by these particles is detected and evaluated.

A unique feature of the D-R 320 is the automatic background light compensation with means of a patented optical system with dual detector. This allows for an easy and quick installation without any adjustment. A light trap is not required.

Key Benefits

  • single sided installation on a standard flange
  • easy startup without adjustment
  • automatic background light compensation without light trap
  • automatic zero and reference point check
  • automatic contamination control and correction
  • integrated purge air regulation and purge air control
  • minimum maintenance
  • EN 15267 certified
  • digital interface according to VDI 4201-3


Continuous emission monitoring, e.g:

  • on incineration plants generally
  • on plants according to IED 2010/75/EU
  • on waste, hazardous waste and sewage sludge incineration plants
  • on cement manufacturing plants
  • on power plants with gas, oil, coal or co-firing
  • on plants for the incineration of biomass

Monitoring of:

  • ventilation units
  • filter units

Download Specifications


Stack, Process & CEMS


Sample gas type Air, flue gas, non flammable process gas
Sample gas temperature 0…600 °C (+32…1112 °F)
Inner duct pressure -50…+50 hPa
Sample gas relative humidity 0…95% RF, non-condensing
Stack/duct inner diameter >0,7 m (>2,3 ft)
Measuring principle Back scattering
Conformities CE
IED 2010/75/EU
US EPA 40 CFR 60 PS11
Certificates CE, QAL1 EN 14181 / EN 15267-1 / EN 15267-2 / EN 15267-3, MCERTS
Measuring location In situ, mounted at stack, device is not in contact with sample gas
Measuring sequence Continuous
System components D-R 320 M measuring head, sender/receiver unit
D-TB 200 supply unit
D-ISC 100 universal operation unit (option)
Self-check, protective functions Automatic zero and reference point check
Automatic contamination correction
Integrated purge air monitoring
Integrated purge air regulation
Fully-integrated fail safe shutter for protection at purge air failure (option)


Physical measuring value Scattered light units, calibrated as dust concentration
Measuring range dust concentration min. 0 …5 mg/m³
max. 0 …200 mg/m³
Output range dust concentration Output range freely programmable. Any range within the measuring range can be assigned to the analogue output.
Certified measuring ranges Dust concentration
0…7.5 mg/m³
Integration time 1…180 s, programmable
Light source, spectral range Laser diode, red
Process connection DN100 PN6 / ANSI 4“ 150lbs RF
Single-sided, on a standard flange in any orientation.
No adjustment at site required; no light trap required.
Digital interfaces RS 485 Modbus RTU, bi-directional communication, USB (Service)
Analog outputs 1x 4-20mA, 400 Ohm, isolated, assignment parameterisable
Digital outputs 2 x contact NC/NO, permissible load 60 VDC / 30 VAC / 0.5 A,
function can be assigned. Typically: maintenance, failure
Power supply 24 VDC, 0,5 A
Operation D-ISC 100 universal operating unit (option),
Service software D‑ESI 100, incl. remote access via web interface (option), requires PC with Windows XP® or Windows 7® OS
Access via USB
Ambient temperature (operational) -40…+60 °C (-40…+140 °F)
IP protection class (IEC 60529) IP65
Dimensions (HxWxD) 200 x 190 x 260 mm
200 x 190 x 410 mm (variants)
Weight Depending on version, approx. 15 kg
Material 1.4571 / 316Ti, painted blue RAL 5017

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