Laser hygrometer

The Aurora Trace moisture analyzer from GE Measurement & Control, uses high definition laser absorption spectroscopy (HDLAS) to provide fast and accurate measurement of the moisture content of gases in the 0-10 parts per million (PPMV) range. It incorporates technology which ensures that its resolution is significantly higher than existing laser absorption equipment, while its sensitivity, or its ability to detect minute amounts of moisture, is increased by a factor of 30. In addition, the response time of the new instrument is the fastest of any currently available system. Typical applications for the Aurora Trace include moisture measurement in the dry feed gas for the LNG liquefaction processes as well as a range of applications in the petrochemical sector where water-detection is process-critical.

Aurora Trace is completely non-contact, as only the laser light and wetted parts come into contact with the process gas. It is designed to monitor continuously, without maintenance, for more than five years and has no need for field calibration or zero gas baselining. In addition to the measurement of moisture concentration, dew/frost point, temperature and pressure “instrument health” parameters are also continuously monitored to assure measurement integrity. An optional verification system is also available.

The moisture analyzer is designed for use in hazardous environments and magnetic induction buttons enable it to be programmed remotely by a magnetic stylus. Consequently, a “hot permit” is not required for programming in a hazardous area, further reducing maintenance costs and simplifying operation. Aurora Trace data is transmitted as three programmable 4-20MA signals or digitally via RS-232/485 with Modbus RTU. Ethernet and Foundation Fieldbus are also available.