Boiler tube, boiler tube unit and furnace

摘要

The boiler tube 2 herein has a longitudinal extension L and comprises radially inner and outer tube parts 4, 6 extending along at least a first part 5 of the longitudinal extension L do. The radially outer tube part 6 is metallurgically bonded to the radially inner tube part 4. A sensor space (8) is disposed between the radially inner tube (4) and the radially outer tube (6), and the sensor space (8) houses a sensor disposed to detect the physical properties of the radially outer tube (6). Is configured to The duct 10 is connected to the sensor space 8 and extends through the radially outer tube 6 to the outlet 12 of the surface of the radially outer tube 6. The radially inner and outer tube portions comprise materials of different chemical composition. Also disclosed herein are boiler tube units and furnaces.