S4 QUASAR - Heated vacuum chemiluminescence NOx analyser

Chemiluminescent Detector (CLD) NOx analysers for NO/NO2/NOx measurement in engine emissions, combustion studies, process plant, Emission monitoring and medical gas production.

Product Description

The S4 QUASAR Heated vaccuum chemiluminescence gas analysers combine high levels of performance with flexibility and ease-of-use in the continuous measurement of NOx, Nitric Oxide, Nitrogen Dioxide or Ammonia.Heated vacuum chemiluminescence is the reference method for monitoring NOx (combined NO and NO2), offering  higher sensitivity with minimal quenching effects, and a heated reaction chamber facilitates the processing of hot, wet sample gases without condensation. The reaction of NO (Nitric Oxide) and O3 (ozone) to produce the chemiluminescence is greatly improved under vacuum, with a better signal to noise ratio, and a fast response time makes it ideal for real-time reporting applications. This method is specified in many standards, such as EN 14792 and Method 7E.

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Technical Specification

Heated sample lines and the analyser vacuum prevent water condensation (without any need to remove it) so that NO2 (Nitrogen Dioxide) cannot dissolve in water. The QUASAR also features a unique neon tube ozonator, which means that (free) air can be used as a feed gas.

Signal Group also provides a non-vacuum and moderately heated Chemiluminescence analyser for applications where trace NOx needs to be measured, for measuring dilute vehicle exhausts from CVS (constant volume sampler) systems and RDE (Real-world Drying Emissions) on-board vehicle testing (for which a 24VDC version is available). Signal Group also recommends this analyser for Emission monitoring applications, however flue gas should be cleaned and dried before the analyser, to maximise maintenance intervals.

Key Features

  • Very low quenching from CO2 and H2O
  • Electronic proportional flow controllers
  • Special ozone generator uses air as feed gas
  • Long life NOx converter (5 years)
  • Dry, low-maintenance pump
  • 24V DC version (ideal for PEMS applications)

Gases Sensed

  • Ammonia
  • Nitric Oxide
  • Nitrogen Dioxide
  • NOx


  • Boiler and Combustion Performance
  • Process Emission Monitoring
  • Automotive
  • Research and Test




Optional Configurations

All Series 4 analysers can be supplied with an optional Wireless tablet with an intuitive menu structure for simple operation, calibration, fault-finding etc. The wireless tablet includes on-board datalogging with a USB memory stick.

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