A current transformer to be installed around a current-carrying conductor. The device is suitable for the forced cooling of a steel strip continuously running in a plant adapted for the continuous annealing or the continuous tempering galvanization. The flow path has a first fluid permeable region, a second fluid permeable region, a barrier that inhibits fluidic flow between the first and second regions, and a fluidic bridge. All or part of the subcooled liquid air can be further cooled within the main heat exchanger. 1Ca4, where U is a running speed of the web, is an average high shear viscosity of the coating liquids, and is a surface tension of the coating liquid for the top layer. When the driver rotates the supporting arm along the recording surface and parks the head in a given evacuation area on the recording surface, a second end of the supporting arm is depressed.