Patent ID: 7345280

Claim:
Method for determining steam quality comprising the steps of: passing a first laser beam at a first wavelength emitted from a first broadband laser along a path through steam in a steam chamber, the steam having a water vapor phase and a liquid water phase, the first wavelength such that the water vapor phase absorbs radiation in the first laser beam at a high level and the liquid water phase absorbs radiation in the first laser beam at a level substantially lower than the high level of absorption by the water vapor phase; passing a second laser beam at a second wavelength emitted from a second broadband laser along a path through the steam in the steam chamber, the second wavelength different from the first wavelength and such that the liquid water phase absorbs radiation in the second laser beam at a high level and the water vapor phase absorbs radiation in the second laser beam at a level substantially lower than the high level of absorption by the liquid water phase; measuring the transmitted intensity of the first laser beam through the steam; measuring the transmitted intensity of the second laser beam through the steam; normalizing the transmitted intensities of the first and second laser beams through the steam; using Beer Lambert's law, determining a total number of water vapor molecules in the path of the first laser beam based on the normalized transmitted intensity of the first laser beam through the steam; using Beer Lambert's law, determining a total number of liquid water molecules in the path of the second laser beam based on the normalized transmitted intensity of the second laser beam through the steam; determining specific volumes of the water vapor phase and the liquid water phase in the steam using the total numbers of water vapor and liquid water molecules; and calculating quality of the steam based on the specific volumes of water vapor phase and liquid water phase in the steam.