Skip navigation


Iron Stream Temp and Tap Time

In the blast furnace, iron ore is combined at high temperatures with carbon in the form of coke to form iron and carbon dioxide.  Limestone is also added as a fluxing agent.  As the iron is formed, it is periodically extracted by tapping a hole at the bottom of the furnace to allow the molten metal to flow out.  Most blast furnaces have multiple tap holes so that one may be opened as soon as another is sealed.

 

Benefits

  • Continuous iron stream temperature during the length of the tap.
  • Automatic indication of tap time.
  • Able to tolerate significant optical obstruction from smoke and dust.
  • Able to compensate for emissivity variation.
  • ESP Filtering feature prevents measurement errors.
  • Sample and Hold feature allows the reading to be held between taps and while the stream is obstructed by heavy smoke.

 

Because the process is completely enclosed, it is difficult to make direct measurements within the blast furnace.  Instead, external measurements are used to understand and control the status of the process.  Continuous iron stream temperature and tap time are critical process parameters that may be used for the optimization of the process.

 

Able to tolerate significant interference from flames, sparklers, and heavy smoke, the Williamson dual-wavelength sensors are uniquely appropriate for this sort of measurement.  With an industry-leading signal dilution factor and advanced ESP Filtering, these measurement issues are handily addressed.  The ESP Filtering feature assures an accurate reading, or no reading at all.

 

Technical Features

  • Optical Obstruction: The sensor tolerates heavy smoke, sparklers, and flames.
  • Emissivity Variation:  The sensor compensates for the severe emissivity variation associated with a molten iron stream.
  • Environment: The sensor is robust enough for the severe environmental demands associated with the blast furnace area, including physical abuse, high ambient temperatures, graphite dust, and an acidic atmosphere.

 

For most blast furnaces, a fiber optic system with the ArmorGuard protective sheathing is recommended.  This feature allows the sensor to be mounted where it can obtain a relatively clear view of the flowing iron stream without concern for the safety of the sensor electronics.  By mounting the sensor in an optimum location, surface slag and a long sight path of heavy smoke may be avoided, and a continuous and accurate measurement may be obtained.