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Hot Blast Main Air Temperature

Hot combustion gas is delivered from the stoves to the blast furnace through a large, refractory-lined duct called the hot blast main.  A consistently high temperature of the blast gas is critical for the efficient operation of the blast furnace. 

 

Traditional thermocouple temperature sensors are susceptible to frequent failure and excessive maintenance as a result of exposure to excessively high temperatures and periodic rapid temperature changes.  Williamson’s infrared thermometers replace these troublesome thermocouples, effectively eliminating the cost and inconvenience of replacement.

 

Benefits

  • Provides reliable and continuous measure of hot blast main air temperature.
  • Eliminates cost and inconvenience of frequent thermocouple changes.
  • Specially filtered to measure hot gas temperature, not refractory wall.
  • More reliable and faster responding than a thermocouple.

 

The Williamson sensor is supplied with a process flange. A three-inch, raised-face, stainless steel process flange is standard.  Custom sizes are available upon request. The sensor is mounted directly to the main blast duct using the same access port as the thermocouple it is replacing.  When properly installed, there is no need to actively cool the sensor, although a purge connection is required.

 

Application Issues

  • Alignment:  D/100 optics allows the sensor to clear the diameter of the existing access port.
  • Wavelength: The sensor wavelength is selected to measure hot blast gasses rather than the blast main refractory walls.
  • Environment: The NEMA4X Williamson sensors survive the severe environmental demands associated with an exterior application in the blast furnace area.