5 furnace setups, Gas Turbine Exhaust: Type K or N, φ0.5–1.5 mm
| Application | Typical conditions | Recommended wire |
|---|---|---|
| Gas Turbine Exhaust | Continuous monitoring of exhaust gas temperature (EGT) for combustion tuning and blade-health trending. 500–650 °C, high-velocity gas stream. | Type K or N, φ0.5–1.5 mm |
| Steam Turbine Inlet | Superheated steam temperature at turbine inlet. 500–600 °C, high pressure. Long-term stability critical for efficiency calculation. | Type K, φ1.0–3.0 mm |
| Boiler Tube Wall | Metal temperature of water-wall and superheater tubes. Prevents over-firing and creep damage. Welded-pad or strap-on installation. | Type K, φ0.5–1.0 mm |
| Nuclear Reactor Core | In-core neutron flux and coolant temperature monitoring. Requires radiation-resistant alloys and rigorous material qualification. | Type N (low cobalt), φ0.25–0.5 mm |
| Waste-to-Energy | Combustion zone and flue gas temperature in municipal waste incinerators. Corrosive atmosphere — high chlorine and sulphur. | Type K with sheath, φ1.0–3.0 mm |
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Long-term stability
Power generation thermocouples often remain in service for years between outages. Type N's superior drift characteristics make it the preferred choice for gas turbine exhaust — especially in combined-cycle plants.
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MI cable for harsh environments
Mineral-insulated cable with SS316 or INCL600 sheath protects the conductors from combustion gases, fly ash and mechanical impact in boiler and turbine installations.
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Redundancy
Critical turbine measurements use dual or triple thermocouples per location. Specify matched EMF output across sensors for valid inter-sensor comparison and voting logic.
Frequently Asked Questions
Which thermocouple type is used for gas turbine exhaust monitoring?
Type N is preferred for combined-cycle gas turbine exhaust, φ0.5–1.5 mm. These sensors often stay in service for years between outages, and Type N drifts far less than Type K at 500–650 °C in a high-velocity exhaust stream.
Why is MI cable specified for boiler and turbine installations?
Mineral-insulated cable with an SS316 or Inconel 600 sheath protects the conductors from combustion gases, fly ash and mechanical impact — conditions where bare or tape-insulated wire fails early.
What is used for in-core nuclear temperature measurement?
Type N with low cobalt content, φ0.25–0.5 mm. The alloy must be radiation-resistant and rigorously qualified as a material before it can be used in-core.
How are critical turbine measurements made reliable?
With redundancy: dual or triple thermocouples per location, specified with matched EMF output so inter-sensor comparison and voting logic stay valid.
Bottom line: Power generation rewards drift resistance above everything else: sensors stay in service for years between outages, so Type N and MI cable with an SS316 or Inconel 600 sheath are the default for gas turbine exhaust and boiler work. For critical turbine measurements, specify dual or triple thermocouples with matched EMF output so the voting logic stays valid.