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DV 425/428 Dust Emission Monitors

Supplier: Phoenix Instrumentation

The DV425/428 are microprocessor based optical measuring systems, which use a dynamic sensing technique to measure the rate of change of light (Dynamic Opacity) as particulates pass through an infrared light beam.


This proven optical technique coupled with advanced design features offers significant reliability and resolution advantages over traditional Opacity monitors and virtually overcomes lens fouling associated with standard Opacity monitors.

The DV425/428 meets European monitoring requirements and are suitable for continuous monitoring of particulate emissions from relatively large stacks, combustion processes, Electrostatic filters as well as other types of arrestment plant.

The DV425/428 series can be calibrated to offer outputs in mg/m3.* The DV425 is suitable for measuring emissions from stacks up to 5m. The DV428 extends this capability to stack sizes of 8m.

*Calibration is via comparison to an Isokinetic test

Principles of Operation

The DV425/428 continuous particulate monitors work on the principle of optical scintillation. This technique monitors the variation in the amount of received light from the light beam transmitted across the stack.

The variation derives from the temporal distribution of particulate which attenuates the light beam. The DV425/428 calculates the dynamic response (ratio of light variation to light intensity or obscuration).

This method has the added benefit that the measurement is unaffected by lens contamination. The instrument response which is proportional to dust concentration is used to calculate Ringelmann, extinction and can also be calibrated to read in mg/m3 by reference to an Iso-kinetic sample (mass gravimetric technique).

  • Suitable for stack sizes to 8m (product specific)
  • In-built continuous compensation for dust on lenses due to Dynamic Opacity measurement principle
  • Simple set-up via keypad operation
  • Operates in high and low dust concentration
  • Unique anti-fouling system minimising contamination from sticky particulate

More Information on DV 425/428 Dust Emission Monitors (pdf) >>