Vibration sensitivity reduction of photoacoustic gas analyzers

Optical gas analyzers are devices for measuring gas concentrations with high precision in industrial environments. Unfortunately mechanical shocks and vibrations can impact the measurement accuracy if the analyzer is installed in noisy environments, e.g. near rotating machines. In this paper, we propose two methods to remove the influence of vibrations by using an auxiliary signal measured via an accelerometer. In the first method, the mechanoelectrical transfer function between the vibration and its effects on the microphone is estimated before installation of the analyzer. In the second method, the mechanoelectrical transfer function is updated continuously under normal sensing operations. The two methods have been implemented within an ABB URAS gas analyzer and corrections are executed in real time. Tests on a vibrating table have confirmed the effectiveness of both methods: a reduction in vibration sensitivity up to a factor twenty is achieved.