Control of protective layer thickness in kilns by utilizing two laser beams

摘要

Methods and devices for protecting incineration kilns by optically determining the thickness of protective refractory and slag layers and taking suitable measures to avoid catastrophic failure due to excessive heat of the outer shell, usually made of carbon steel. The determination is performed by two laser beams. One laser beam is directed at low incidence at various points of the top surface of the protective layers inside the kiln, while the second laser beam is directed at a different incidence at the same points of the top surface of the protective layers inside the kiln.