Tunable diode laser dew point analyser

Aurora Moisture Analyser

low maintenance
quick speed of response
high accuracy and reliability

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The Aurora moisture analyser provides a wide range of reliable measurement with the accuracy and fast response needed for immediate alerts to process upsets or out-of-compliance moisture concentrations.

Using a laser to monitor low level humidity offers a number of key benefits.

This robust, non-contact analyser is highly accurate with an extremely rapid speed of response, and has led the industry to a new era in water vapour measurement. The ability to monitor humidity in near real time has led to significantly improved confidence in the measurement, and improved process efficiencies. The speed of response of the analyser enables rapid detection and recovery from process upsets, allowing easier diagnosis of plant problems and rapid return to normal process level, allowing quick return to shipping product.

The graph below shows the difference in response between a laser system and a more traditional aluminium oxide sensor to short bursts of water vapour. The laser shows a full scale deflection, while the aluminium oxide shows hardly any change.

speed of response graph 





Water vapour

Measurement principle

Absorption spectroscopy using a tunable diode laser


ppmv: application dependent

Lower level of detection

application dependent

Dew/frost point



ppmv ±2 % of reading or 4 ppmv

Response time

Optical response: ‹2 secs

System response dependent on build of sample systme, flow rate and pressure, and changes in moisture concentration

Operating pressure

Operating sample cell pressure: 69 to 172 Kpa (10 to 25 psia)

Maximum pressure: 1380 Kpa (200 psi)

Process pressure: 10,342 KPa (1500 psig) maximum

(Higher pressure available with additional components)


Operating temperature: -20 to 65 °C

Storage temperature: -20 to 70 °C


Sample cell flowrate 10 to 60 SLH (0.4 to 2 SCFH); 30 SLH (1 SCFH) nominal

Coalescer by-pass fast loop: 5 to 10X of flowrate through sample cell


Backlit LCD


Recommended factory verification/service: 5 years 



Explosion-proof for Class I, Division 1, Groups C&D

EU and elsewhere

ATEX and IEC Ex: Ex de IIB T6 -20 °C to +65 °C

Flameproof with increased safety compartment


CE marked. Complies with EMC directive 2004/108/EC, low voltage directive 2006/95/EC and pressure directive 97/25/EC


Net weight

37 Kg (100 lb)



46w x 332.3d x 841.2h mm

Ingress protection








All specifications subject to change