A device for repairing underground sewers, pipe or the like provided a cylindrical hollow body, which has an elastically expandable casing acting as an outer wall. The disclosed system and method use an optical immersion probe including a flow gap across which two or more types of radiation are transmitted in order to measure absorptions of two or more substances within the multiphase flow. With the second switches of the switch groups alternately switched ONOFF, electrical power is fed to a circuit system, which includes a power storage device or an application device of loading. The self-expanding stent is compliant meaning that it may expand to the actual size of the space into which it is placed.