QAL 181 Particulate CEM

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The QAL 181 is the ultimate approved particulate Continuous Emission Monitor (CEM). It provides high quality emission measurement for low dust concentrations from industrial processes particularly incineration and power generation.

4 x QAL1 certified ranges, including 0 – 7.5 mg/m3, the lowest achievable for any Particulate CEM

It is the total solution for applications where CEN standards EN 14181 / EN 13284-2. QAL 181 holds QAL1 approval as specified in EN 15267-3, under MCERTS.


QAL 181 advantages include:

  • Complies with Waste Incineration and Large Combustion Plant Directives EN13284-2 and EN14181
  • ProScatter™ technology offers enhanced measurement due to reduced cross-sensitivity of particle type and size
  • ProScatter™ forward-scatter technology with a minimum detection limit of <0.05mg/m3
  • Adjustable monitoring depth to ensure sampling in the most representative part of the flow path
  • Automated QAL3 reporting in full compliance with EN 13284-2
  • Robust design for high temperature stack conditions and Ex hazardous zones

Resolution and Sensitivity

The QAL 181 uses a low-angle forward light scattering measurement principle unique to ENVEA (see ProScatter™ Forward Scatter). The measured cone of scattered light is larger than normal for light scatter instruments, which provides:

  • Excellent sensing resolution and sensitivity, due to an increased signal-to-noise ratio
  • Reduced cross-sensitivity to changing particle size, allowing a greater range of applications for which the instrument is suitable

Inherently Reliable Design

Using tough high-grade components and enclosures, and designed to overcome problems encountered with alternative light scatter technologies, the QAL 181 offers outstanding reliability:

  • No optical fibres, which are prone to degradation in elevated temperatures
  • No moving active measurement parts, ensuring sensing components remain correctly aligned.
  • The QAL 181 avoids this by introducing a diffuser into the light path, which gives the additional benefit of a true check of the instruments ability to measure scattered light, rather than just attenuated light


Inbuilt Quality Assurance

The QAL 181 ProScatter™ technique benefits from improved levels of performance. When compared to other forward-scatter systems, its increased area of detection (more than 10x larger) and smaller angles of incidence reduces variability in sensitivity and measurement.

The QAL 181 sensor has automatic zero and span self-checks that fully challenge the forward-scatter measurement technique. In addition, internal diagnostic checks ensure a high level of confidence in the measurement. This permits early diagnosis of any deterioration in system performance.

The sensor self-checks ensure appropriate quality assurance to meet the QAL3 regulatory requirements for particulate compliance monitors installed on Incinerators, Cement Kilns and Power Plant in Europe (EN13284-2).


Technical Data

Measurement capability 0 – 1000 mg/m3
QAL1 certification range 0 – 7.5 mg/m3
0 – 15 mg/m3
0 – 100 mg/m3
0 – 200 mg/m3
Resolution 0.01 mg/m3
Sensor Variants Stainless Steel (standard). Corrosion resistant Hastelloy (option)
Stack Temperature Ranges 0-250°C. Up to 500°C option
Functionality and QA Checks Automatic zero and upscale checks QA data logging
Data Output RS485 (Modbus) output to Controller
Air Purge Requires continuous air purge
Enclosure Protection Rating IP66


A Proven Particulate CEM

The QAL 181 supersedes the LMS181, an instrument currently proven in many applications worldwide.

Additional Information

Weight 6 kg




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