Abstract: A method and an apparatus for joining two workpieces by means of a processing beam by forming a weld seam along a lap joint, wherein a gap formed at the lap joint between the two workpieces is filled during welding. The processing beam performs a spatial oscillatory movement parallel and/or perpendicular to the joint during welding. The oscillation parameters of said oscillation, the feed rate, the power of the processing beam and the angle of incidence of the processing beam onto the surfaces of the workpieces are adjusted dynamically during the welding process such that the upper sheet is fused in line with demand and the melt flows from the upper sheet down to the lower sheet thus closing the gap. The gap height is measured permanently during welding and the process parameters are adjusted such that a reliable closing of the gap is made possible.

Abstract: The invention relates to a method and also a device for producing a gas product, wherein a first gas stream is combined with a second gas stream and the first gas stream that is present at a lower output pressure than the second gas stream is fed to a mechanical compressor in order to be compressed to the preset pressure of the gas product. It is characteristic in this case that the pressure of the first gas stream is elevated using a gas jet compressor arranged upstream of the mechanical compressor, to which gas jet compressor at least a part of the second gas stream is fed as pumping medium.