GAS ANALYSERS BASED ON TUNEABLE DIODE LASER SPECTROSCOPY: A NEW COMPACT, DIGITAL, LOW-POWER ANALYSER DESIGN

摘要

Gas Analysers based on tuneable diode laser absorption spectroscopy (TDLAS) in the near infrared were introduced to the market more than 10 years ago. Important features of TDLAS are the speed of response, non-contact in-situ measurement, high dynamic range, and zero cross interference from background gases. Developments in digital electronics and specifically in high speed, high resolution analogue-to-digital (A/D) converters have been considerable over the past years and now enable TDLAS electronic design concepts that were not possible in the early days of TDLAS. This paper presents a new electronic TDLAS design that is fully digital, enabling response times of 100 ms or lower. Moreover, it is very compact and will fit into analysers with a footprint of less than 10 × 10 × 20 cm. These analysers can be designed intrinsically safe (EEx ia) for the measurement of Oxygen and other gases in hazardous areas.