Fixture used for the heat sealing of foils using a plasma jet

Fixture for heat-sealing foils along a welded joint wherein a first foil layer is superimposed over a second foil layer, the superimposed layers having opposite outer sides, and wherein the foil layers are heat-sealed with a plasma jet by application of the plasma jet to only one side of the superimposed layers, wherein said plasma jet is moved across said only one side of said superimposed layers to form a welded joint between said superimposed layers, said fixture including a plasma nozzle and a conveying device, which generates a relative movement between the plasma nozzle and the foil layers along the weld joint.