High temperature combustion, annealing and melting processes are usually executed without pressure at temperature up to 1800 °C (3272 °F). As a result, the selection of the appropriate thermowell is the greatest challenge for temperature measurement. 

Straight thermocouples for high temperature applications in industrial furnaces, combustion processes and melting processes. It communicates via  4 to 20 mA, HART, PROFIBUS PA, FOUNDATION Fieldbus or direct sensor output. Approved ABB typical modular system:

TSH210 with metal thermowell, for temperatures up to 1300 °C (2372 °F)

TSH220 with ceramic thermowell, for temperatures up to 1800 °C (3272 °F) 

suitable to main process connections

suitable to main process control systems