Abstract: A gas flow reversing element is provided comprising a main piece defining at least one closable outlet opening, a branching piece extending from the main piece, a line connector connected to the distal end of the branching piece, a pressure connector connected to the main piece, the pressure connector being structured to be fluidly connected to a pressurized gas supply; and a nozzle being configured and arranged in the main piece in such a way that a gas flow flowing in the main piece from the pressure connector through the nozzle to the at least one outlet opening, with the at least one outlet opening being disposed in the second open position, a gas flow can also be generated in the branching piece in a direction toward the at least one outlet opening.