THE LIGHTWISE^TM PROBE

LTG has designed a patentable analytical probe that facilitates a "clean" optical path, as required for spectroscopic analysis, while at the same time reducing the effects of soot, dust, and droplets commonly present in ducts and stacks. The probe is comprised of a transmit/receive telescope, a  sampling tube, and a corner-cube retro-reflector chamber (mounted at the end of the sampling tube).

While the telescope module is installed outside the flange that provides access to the duct, both the sampling tube and the retro-reflector are inside the duct. Consequently the external components are designed to withstand extreme weather conditions and the internal components are designed to survive in an environment containing ash, dust and hot corrosive gases.  The tube portion of the probe is a partially open, cylindrical, hollow structure that holds the telescope at one end and the retro-reflector at the other. Double its length thus defines the absorption sample path-length. In order to facilitate sampling of the flowing flue gases and in the same time reduce the attenuation and contamination of the ash and dust, the tube surface has an aerodynamic profile that deflects particulate and literally sucks in the relatively ash free gases from a down-the-stream aperture. 

The corner cube module is a cylindrical container in which the retro-reflector is mounted on graphite o-rings and spacers. The graphite protects the retro-reflector from the effects of uneven thermal expansion of the various construction materials.  Quartz windows protect both the telescope and retro-reflector modules from the hostile flue environment. The probe provides a 1.5-meter optical distance, which translates into a 3-meter spectroscopic/analytical path.