Heating device for heat-sealing bottom portions of containers

摘要

A heating device for heat-sealing bottom portions of containers has a hot air nozzle. The nozzle is positionable as opposed to a bottom forming end portion of a tubular blank of square cross section as fitted around an intermittently drivable mandrel for heating a region of the blank end portion. The nozzle is movable toward or away from the end portion on the axis of the blank. The nozzle has orifices directed toward a plurality of parts within the region when the nozzle is positioned close to the end portion. Among the orifices of the nozzle, those directed toward the part of the region remote from an extremity of the blank when the nozzle is so positioned have a greater open area ratio than those directed toward the part of the region proximate to the blank extremity when the nozzle is so positioned.