An exhaust stack having a junction tube and a flue is provided. At least one massage node is mounted on each of the massage node bases and at least partially protrudes from the top surface. Further, the sealed terminal includes a terminal pin, which is formed from a conductive material, a terminal holder, and an insulative body. At least two displacement pumps are provided to produce a fluid flow under pressure to the consumers, whereby at least one control valve is provided for each of the consumers. The sensor magnet is fastened on the cylinder rod rotatably with respect to the cylinder rod and is guided non-rotatably with respect to the cylinder housing.