Impulse heat sealing of a heat-sealable film material

A sealing station configured to heat seal a wall made from heat-sealable film material onto an annular attachment flange of a plastic spout made from heat-sealable material to create a sealed joint between the annular attachment flange and the wall,

• wherein the sealing station comprises:
• an impulse sealing device comprising a first jaw and a second jaw,
• an actuator device configured to move the first and second jaws relative to one another between an opened position and a clamped position,
• a cooling device configured to cool at least one of the first and second jaws,
• wherein the first jaw has a first front surface configured to contact an annular seal region of the wall made from heat-sealable film material,
• wherein the second jaw has a second front surface configured to contact an annular seal region of the annular attachment flange of the plastic spout made from heat-sealable material,
• wherein the first jaw comprises at the first front surface an impulse heatable member that extends along the first front surface and that is covered by a heat-resistant non-stick covering,
• wherein the sealing station is configured to perform an impulse sealing cycle, wherein the actuator device is configured to bring the first and second jaws into the clamped position, so that the annular seal regions of the wall and the annular attachment flange are clamped against one another by the first and second jaws, and wherein the sealing station is configured to, in the clamped position, temporarily energize each impulse heatable member so as to generate an impulse of heat that is emitted by each heatable member, which impulse of heat seals the annular seal regions of the wall and the annular attachment flange to each other, wherein at least one of the first and second jaws is cooled by the cooling device after termination of energizing of the impulse heatable member, and wherein the actuator device is configured to move the first and second jaws into the opened position after the impulse heatable member has cooled down,
• wherein the impulse heatable member of the first jaw is an annular susceptor element of electrically conductive material, said annular susceptor element extending about a central axis that is perpendicular to the first front surface and having a rear side facing away from the first front surface,
• and wherein the first jaw comprises an inductor at the rear side of the annular susceptor element, wherein the inductor is electrically insulated from the annular susceptor element,
• wherein the inductor comprises an inner inductor section and an outer inductor section, which extend adjacent one another and concentrically about the central axis, spaced from one another by a slit, wherein the inner and outer inductor sections are interconnected in series,
• and wherein the sealing station comprises a high frequency electric current source, which is connected to the inductor,
• wherein the sealing station is configured so that, in the impulse sealing cycle, the high frequency electric current source is operated to temporarily feed a high frequency electric current to the inductor, which flows through the inner and outer inductor sections in opposite directions, thereby generating a high frequency electromagnetic field with the inductor, wherein the high frequency electromagnetic field induces eddy currents in the annular susceptor element generating an impulse of heat that is emitted by the annular susceptor element, which impulse of heat seals the annular seal regions of the wall and the annular attachment flange to each other.