Hot air welding process for closure of thermoplastic bags and sachets

摘要

The method is applied to workpieces (10) conveyed between two endless belts driven by wheels in opposite directions. The mouths of the bags pass in succession in front of a heater installed at the entrance to parallel sections of the belts between spring-biased pressure components. The lips are guided (28) towards a projection (24) from a crosspiece (22) into their path. The leading corner (13) is held momentarily in a slot (26) while the upper edges of the opened bag proceed on either side of the projection. A jet of hot air is blown (27) to expel any dust and to soften the lips before they are pressed together.