Measuring nitrogen oxides concentration involves using specific discharge lamp in which electrically rotating filtering or screen wheel is placed in radiation path and controlled

摘要

Process for measuring NOx concentration involves using a specific discharge lamp as radiation lamp in which an electrically rotating filtering or screen wheel (4, 5) is placed in the radiation path with a radiation source (1), cuvette (2) and detector and controlled so that the measuring time is more than the transfer time. An Independent claim is also included for a device for the NOx measurement. Preferred Features: The measuring time is a multiple larger than the transfer time. The step width is determined to minimize the transfer time for each measurement so that the filter and/or screen wheel can be transferred directly between the measuring and comparison position. Small concentrations of NOx are detected.