of the gas nozzle 18 is indicated by an arrow 25 and the sideways movement by an arrow 26 the sideways movement of the gas nozzle 18 is superfluous if the protective gas is blown in from the side of the conveyor belt i e displaced by 90 u00b0 from the illustrated arrangement two holding clamps 27 serve to affix the lid 19 on the edge of the container 10 the vertical movement of said clamps being represented by the arrows 28 fig4 and 5 show another execution of the invention on the sections 29 30 and 31 of a conveyor belt are the synthetic material containers 33 34 and 35 the transport direction of the conveyor belt is indicated by the arrows 32 the aluminum lids 36 37 and 38 are positioned on the synthetic material containers 33 35 the center work station at which the synthetic material container 34 is positioned shows the lifting of the cover 37 and theflushing with protective gas according to the invention a fixed wedge 39 serves to lift the lid 37 when the synthetic material container 34 moves forward this wedge slides in the transport direction under the tear off tongue of the lid 37 and lifts it slightly corresponds to its thickness through a boring with supply connectors 41 at the thick end of the wedge 39 the protective gas 42 is blown in the escaping gas is represented by arrows 43 in this variation of the procedure the fastening of the lids 36 37 and 38 takes place with spot welds 44 45 and 46 the procedure according to the.