Light from a Mercury Vapor UV lamp (6) passes through a sapphire window (2), and then through the process stream (1). The resulting light passes through a UV filter (3) and is detected by a photodiode (4).
The narrow-band pass UV filter blocks all wavelengths except the specified UV wavelength. The photocurrents induced are directly proportional to the remaining light intensity at this wavelength.
Light from the Mercury Vapor Lamp UV (6) also passes through a lamp reference filter (5) and lamp reference photodiode (5) installed within the lamp assembly. This compensates for any variations or intensity fluctuations of the UV lamp.
The resulting photocurrents are precisely amplified, converted, and analyzed by the converter. The converter provides real time measurements and can send outputs to the process control system.
