Measuring dust emissions is easy – if one has the right measuring equipment. When it comes to choosing the right measuring device, one has to look at both the properties of the medium to be measured and the environmental conditions. This is where SICK’s strengths really come into their own – tried-and-tested measurement principles applied in a diverse portfolio of products and combined with decades of experience in thousands of different installations. It is not simply a question of complying with legal requirements. But which measurement technology is best? Which device version is most suited to the task at hand?

When  it  comes  to  a  certain aspect, all measurement technicians only want one thing: rugged measuring devices that provide accurate and  fast  measurements  with a high  level of availability. The more detailed the description of the task at hand, the easier it is to provide a safe and cost-effective  measurement.

And  this  does  not  just  apply  to  the  initial  investment  costs,  it  applies for the device’s entire operating  life. Whether it is used for dry, corrosive, or hot flue gases. Whether it is used in  process  control  for  measuring  moist  emissions, for the smallest concentration  of dust following fabric and bag filters, or  for high concentrations of dust in raw gas  prior to electric filters. For personal and  occupational  safety  purposes,  fine  dust  with  particle  sizes  in  the  low µm range  have to be monitored in the air in production halls. SICK’s dust measuring devices can even provide effective and accurate measurements for the excessive development of dust by grinders in quarries.

Anything is possible


Environmental standards are becoming more stringent, often requiring companies to measure low concentrations of dust. This task requires a particularly sensitive measuring process.

Ever since Erwin Sick conducted his pioneering work in 1956, SICK has been concentrating on optical measurement processes. The scattered light approach provides the best foundation for recording even the lowest concentration of dust.

This also applies for more demanding applications in hot or aggressive gases with low to medium dust content. The DUSTHUNTER SB50 and SB100 scattered light dust measuring devices apply the backward scattering principle. Installing the devices in a stack is easy: a single opening is enough.


DUSTHUNTER: More flexibility thanks to multiple device versions

Stacks with thicker walls require dust measuring devices to have a special shape without sacrificing any of the measurement accuracy, even for the lowest concentrations of dust. other stacks require the measuring device to be installed in one exceptionally small opening. For these two scenarios, the DUSTHUNTER SP100 comes with a special probe with graduated lengths from 435 to 2,435 mm. The maximum drill hole diameter required is 130 mm.

Made from stainless steel, titanium or Hastelloy, the probes are well equipped to withstand hot or corrosive substances. The DUSTHUNTER SP100 also uses the scattered light principle, applying highly sensitive forward scattering. The DUSTHUNTER SF100 is SICK’s solution for particularly difficult cases when it comes to the shape of the stack and the properties of the medium. If the flow is affected by inhomogeneities or swirling in larger channels, it can make representative dust measurement more difficult. The problem can only be solved by taking a measurement across the entire diameter of the stack.

The DUSTHUNTER SF100 also uses the scattered light principle (forwards scattering). Its receiver is installed opposite the sender on the other side of the stack, making it the ideal solution for measuring larger diameters. It can even measure the lowest concentration of dust with maximum precision. However, it is also suitable for use with corrosive and hot media. The DUSTHUNTER SF100 makes almost no contact with the medium itself.

Measuring medium or high concentration of dust

single measurement  across  the  entire  cross  section of the stack quickly records the concentration values. Transmittance also uses a conventional  optical process, making it ideal for measuring medium to high concentrations of  dust: the DUSTHUNTER T50, T100, and T200 transmittance dust measuring devices.

The  DUSTHUNTER  T50  is  all  you  need  to  tackle  simple  measurements.  Like SICK’s measuring devices that use the scattered  light  principle,  the  DUSTHUNTER  T100  includes  an  automatic contamination measurement and correction  function.  It  provides  users  with  an early  warning  should  the  contamination  level on the measurement optics exceed the permitted  limit.

The DUSTHUNTER T200 is also equipped with an automatic  self-alignment  function  for  the  optics:  a  unique  feature  only  available  in  SICK products. It corrects any distortion on the optical axis that may occur as a result of  the thermal expansion of the stack. Both functions reduce excessive maintenance cycles. The  automatic self-alignment function also makes it easier to commission the device.

Sometimes, things may get a little damp…


In  some  processes,  exhaust  gases  are  cleaned  in  scrubber  units  before  they are released. Recording a reliable  measurement  for  dust  concentration  is  particularly  difficult  when  the  dust  is  damp.

Conventional  dust  measuring  devices  cannot  differentiate  between  specks of dust and drops of water, leading to distorted measurement readings.  only  one  thing  can  help  here:  using  a  bypass  system  to  extract  the  medium  from  the  stack,  dry  it,  and  then  measure  it.

This  is  the  approach  applied  by  the  extractive  scattered  light  dust  measuring  device,  the FWE200DH.  It  extracts  flue  gas  from  the  stack  on  a  permanent  basis,  dries  it  within  a  few  seconds  using  a  thermo  cyclone,  and  records particularly low concentrations  of  dust  accurately  using  forward  light  scattering.  The  FWE200DH  features  a  space-saving design and can therefore  be  installed  straight  into  the  stack.  It  is  equipped  with  a  corrosion-resistant  sampling probe made from PVDF.

… and sometimes extremely dusty

Dust extraction systems play a key role in  the purification of air. Filter defects have  to be detected at an early stage before the  system  can  exceed  the  specified  limits. The FW102 scattered light dust measuring device is installed on one side of the  clean gas duct downstream from the filter.  It measures dust regardless of the gas velocity, humidity, or dust particle charges.