Abstract: The present disclosure relates to a tube structure comprising an inner tube of metal and an outer tube of metal, wherein the inner tube extends in the outer tube, and wherein either the inner tube and the outer tube are mechanically tight fitted over the entire length of the inner tube, at least one space in a radial direction of the tube structure in the form of a groove extends at least in an outer surface of the inner tube or in an inner surface of the outer tube, and the at least one space extends in a longitudinal direction of the inner tube and over an entire longitudinal extension of the inner tube, or a spacer tube is located between the inner tube and the outer tube, the inner tube, the outer tube and the spacer tube are mechanically tight fitted over the entire length of the spacer tube, the spacer tube comprises at least one space in the form a slit extending in a radial direction of the tube structure from an outer surface of the inner tube to an inner surface of the outer tube, the at least one s

Abstract: The present disclosure relates to a tube structure comprising an inner tube of metal and an outer tube of metal, wherein the inner tube extends in the outer tube, and wherein either the inner tube and the outer tube are mechanically tight fitted over the entire length of the inner tube, at least one space in a radial direction of the tube structure in the form of a groove extends at least in an outer surface of the inner tube or in an inner surface of the outer tube, and the at least one space extends in a longitudinal direction of the inner tube and over an entire longitudinal extension of the inner tube, or a spacer tube is located between the inner tube and the outer tube, the inner tube, the outer tube and the spacer tube are mechanically tight fitted over the entire length of the spacer tube, the spacer tube comprises at least one space in the form a slit extending in a radial direction of the tube structure from an outer surface of the inner tube to an inner surface of the outer tube, the at least one s

Abstract: A tube structure (1) comprising an inner tube (3) of metal and an outer tube (2) of metal, wherein the inner tube (3) extends in the outer tube (2), wherein a spacer tube (4) is located between the inner tube (3) and the outer tube (2), wherein the spacer tube (4) comprises at least one slit (5), wherein the at least one slit (5) extends in a longitudinal direction of the spacer tube (4) and over an entire longitudinal extension of the spacer tube (4), and wherein the at least one slit (5) forms a space in a radial direction of the tube structure (1) extending from an outer surface (7) of the inner tube (3) to an inner surface (8) of the outer tube (2), wherein the tube structure (1) further comprises at least one signal line (9) located in the at least one slit (5) of the spacer tube (4), wherein the at least one signal line (9) extends in the longitudinal direction of the spacer tube (4).

Abstract: Herein a boiler tube (2) having a longitudinal extension (L) and comprising radially inner and outer tubular portions (4, 6) extending along at least a first part (5) of the longitudinal extension (L). The radially outer tubular portion (6) is metallurgically bonded to the radially inner tubular portion (4). A sensor space (8) is arranged between the radially inner tubular portion (4) and the radially outer tubular portion (6), wherein the sensor space (8) is configured to accommodate a sensor arranged to detect a physical property of the radially outer tubular portion (6). A duct (10) is connected to the sensor space (8) and extends through the radially outer tubular portion (6) to an exit portion (12) of a surface of the radially outer tubular portion (6). The radially inner and outer tubular portions comprise materials of different chemical composition. Also, a boiler tube unit and a furnace are disclosed herein.

Abstract: Method for manufacturing a tube of metal in which sensors are attached to tubes, which register and signal a damage of the tube. It is detrimental that protection of the sensors at these tubes against environmental influences is complex. In contrast, it is an object of the present disclosure to provide a method for manufacturing a tube, in which the signal line can be protectively mounted. To solve this object, a method for manufacturing a tube of metal is suggested with an outer tube and an inner tube, wherein a groove is drawn in an inner surface of the outer tube or in an outer surface of the inner tube and subsequently the inner tube and the outer tube are drawn together through a drawing die, wherein the inner dimension of the outer tube is reduced such that after the drawing the outer tube is force-fitted onto the inner tube.

Abstract: A tube structure (1) comprising an inner tube (3) of metal and an outer tube (2) of metal, wherein the inner tube (3) extends in the outer tube (2), wherein a spacer tube (4) is located between the inner tube (3) and the outer tube (2), wherein the spacer tube (4) comprises at least one slit (5), wherein the at least one slit (5) extends in a longitudinal direction of the spacer tube (4) and over an entire longitudinal extension of the spacer tube (4), and wherein the at least one slit (5) forms a space in a radial direction of the tube structure (1) extending from an outer surface (7) of the inner tube (3) to an inner surface (8) of the outer tube (2), wherein the tube structure (1) further comprises at least one signal line (9) located in the at least one slit (5) of the spacer tube (4), wherein the at least one signal line (9) extends in the longitudinal direction of the spacer tube (4).

Abstract: A signal transmission system or a sensor system comprises at least one signal line and at least one sensor connected to the signal line, a first tube formed of a metal strip or metal plate having two longitudinal edges extending in a longitudinal direction and two transverse edges connecting the longitudinal edges, wherein the metal strip or metal plate is formed to a cavity by joining the longitudinal edges of the metal strip or metal plate together, and wherein the at least one signal line is located in the cavity. A method for manufacturing such a signal transmission system or a sensor system is also disclosed.

Abstract: Method for manufacturing a tube of metal in which sensors are attached to tubes, which register and signal a damage of the tube. It is detrimental that protection of the sensors at these tubes against environmental influences is complex. In contrast, it is an object of the present disclosure to provide a method for manufacturing a tube, in which the signal line can be protectively mounted. To solve this object, a method for manufacturing a tube of metal is suggested with an outer tube and an inner tube, wherein a groove is drawn in an inner surface of the outer tube or in an outer surface of the inner tube and subsequently the inner tube and the outer tube are drawn together through a drawing die, wherein the inner dimension of the outer tube is reduced such that after the drawing the outer tube is force-fitted onto the inner tube.