D-R 300

Scattered light monitor

Certified scattered light dust monitor to detect smoke spot number in dry flue gas.


  • in situ measurement, continuous measurement
  • suitable for systems with variable stack gas speed
  • allows calibration to measure the smoke spot number in flue gas
  • device is not in contact with sample gas
  • automatic zero and reference point check
  • automatic measurement and correction of soiling of optical surfaces
  • hermetically sealed enclosures - no flue gas diffusion to optics or electronics
  • optimized purge air reduces pollution, provides for long maintenance intervals
  • heated optical window
  • easy installation, adjustment and maintenance without a PC
  • local control panel displays output signal
  • automatic range switching output


Suitable for measurement of smoke spot number in

  • furnaces designed for light fuel oil
  • fine dust measurements in processes

Technical Data

measurementsscattered light units, calibrated as smoke spot number
sample gasflue gas, non flammable process gas
smoke spot number0 - 3 (5)
duct diameter> 0,3 m
sample gas temperature-25 … 320°C, others on request
sample gas pressure
(relative to ambient pressure)
-50 to +20 hPa, others on request
sample gas moisture< 95% relative humidity (not condensing)
ambient temperature-20 to +50 °C, others on request
measuring principlemeasurement of light intensity being scattered backwards by dust particles
light sourcehalogen lamp white, > 10.000 h
typeIn situ, mounted at stack, device is not in contact with sample gas
system componentsD-R 300 M Measuring head, sender- receiver unit
D-R 300 L Light trap
D-R 300 B Control and display unit
D-BL Blower unit
measuring rangessmoke spot number 0-3 (range defined by optical apertures)
output rangesscattered light units are scaled smoke spot number to 2 analog outputs
process connectionflange hxwxd ca. 400 x 200 x 30 mm
power supply230 V 50/60 Hz, 70 VA
115 V 50/60 Hz, 70 VA*
from D-R 300 B
dimensions (h x w x d)570 x 310 x 200 mm
weightca. 18 kg
materialAl-cast alloy, painted RAL 5017
measured value output2 x 4-20 mA / 500 Ohm
status output3 relay outputs,
max. load 48 V / 0,5 A
status input1 potential free input
power supply230 V 50/60 Hz, 70 VA
115 V 50/60 Hz, 70 VA*
protectionIP 65
dimensions (h x w x d)160 x 180 x 140 mm
dimensionsvariants, dependant on duct diameter
material1.0037, painted
1.4571, painted*
purge air flow ratemax. 40/60 m3/h at dPtot 50/25 hPa, others on request
power supply115 / 230 VAC, 50 / 60 Hz, 0,37 / 0,43 kW,
others on request
protectionIP 55
dimensions (h x w x d)480 x 450 x 320 mm
weigth12 kg
remarks* variants
Subject to technical modifications!

Your contact options