Our sight glass assembly was designed for use with high temperature furnace systems. The unique design permits thermal distortion-free viewing of a heated cavity. The window minimizes thermal distortion associated with other sight ports by providing a curtain of heat at the entrance of the cavity to reduce convective and radiative heat transfer. The sight glass was developed for the Mellen EDG Furnace, but may now be applied to other furnaces as part of our Intelligent Processing of Materials project.

By controlling the power level to the auxiliary window heaters separately from the main furnace heaters, a concentrated curtain of heat is maintained at the entrance to the sight port.

Testing has shown that the heat input of the window heaters can minimize the thermal disturbance created by the existence of the sight port.


PDFs on the Sight Glass
Sight Glass Additions
  • Closeable Apertures
  • Automatic Temperature Control of Window Heaters
  • Special Sight Glass Materials and Coatings
  • Water-Cooled Sight Glass Housings

As always, if this product does not meet your requirements, please contact us. Mellen will work with you personally to create a product that best suits your needs every time.