🔍 Key Concepts

• Exhaust gas pyrometer operation – how thermocouples sense temperature by direct contact with hot gas/metal • Effect of insulating deposits (like carbon, scale, soot) on heat transfer to a sensor • Difference between a sensor that responds slowly and lower vs quickly and higher than actual temperature

💭 Think About

• Think about what happens to heat transfer when a coating builds up between the hot gases and the thermocouple tip – does it make heat flow easier or harder? • If the thermocouple is partially insulated by carbon, will the junction get hotter than the gas, cooler than the gas, or just slower to follow temperature changes? • Which options describe behavior caused by better insulation versus better conduction?

✅ Before You Answer

• Verify that carbon deposits act more like an insulator than a good heat conductor at the thermocouple tip • Decide whether an insulated thermocouple would tend to show a temperature higher or lower than the true gas temperature at that location • Check which options claim faster response versus slower or damped response, and match that to an insulated sensor.