QAL991 Particulate Monitor

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Envea’s QAL991 is a QAL1 approved particulate CEM (Continuous Emission Monitor).

Once operational in industrial processes with high efficiency bag filtration, the ElectroDynamicprobe provides high quality dust measurement in low concentrations.

Therefore, the QAL 991 is particularly suited to monitoring emissions from waste incineration and power plants. Sites which are regulated under the Industrial Emissions Directive (IED).

QAL 991 is designed to meet and exceed CEN standard EN 14181 / EN 13284-2. The instrument holds QAL1 approval specified in EN 15267-3, under both MCERTS and TUV.


The sensor measures the current signature created by particles interacting with the sensing rod which protrudes into the stack. The technology outperforms conventional DC triboelectric systems and alternative AC systems. It extends the velocity range over which the instrument has no cross sensitivity to changing velocity.

QAL991 Benefits

  • The robust design of QAL991 is unaffected by build-up on the sensor rod which eliminates signal drift.
  • Automatic recording of drift checks (zero and span) to satisfy QAL3 requirements
  • Complies with standards EN 13284-2, EN 14181 and EN 15267-3 and applications with Emission Limit Values (ELVs) of 7.5 mg/m³ (Incineration) and 15 mg/m³ (co-incineration)
  • The internal Quality Assurance features of the instrument have been designed and approved to meet the QAL3 and AST requirements of EN14181.


Control Unit

  • Icon driven, interface screens feature alarms, graphical trends, data logging, 4-20mA output
  • PLUS control unit option for sensor networking (up to 16 sensor channels) via industry standard Modbus, multiple inputs for external devices (e.g. for Temp and O2 normalisation)


The QAL 991 supersedes the DT991, an instrument that’s proven in the most demanding CEM applications.

Additional Information

Weight 6 kg



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