Patent ID: 8444804

Claim:
A method of sealing layers of film together to form a sealed portion and a notch within said sealed portion, said method comprising the steps of: (a) providing layers of film to be sealed together between a heat-sealing jaw and a cooperating backing jaw, said heat-sealing jaw comprising i) a jaw body; ii) a heat-sealing element secured to said jaw body, said heat-sealing element comprising a first end and a second end, said heat-sealing element having a clamping portion and a sealing face for pressing said layers of film together against said opposing backing jaw, wherein said clamping portion is proximate to said second end of said heat-sealing element, wherein said clamping portion is disposed at an orientation diverging from said sealing face, and wherein said sealing face has a length and a protrusion extending partly along said length of said sealing face for forming said notch within said sealed portion; iii) a support surface comprising at least a portion of at least one of the heat-sealing element, an additional separate element, and the jaw body associated with the heat-sealing element for clamping the layers of film against the opposing backing jaw; and iv) a heat-sink comprising at least one of an additional separate element and the jaw body coupled to the heat-sealing element at a location adjacent to the support surface, which, during operation, induces a temperature gradient along the sealing face of the heat-sealing element in the longitudinal direction of the sealing face; (b) inducing a temperature gradient along said length of said sealing face of said heat-sealing element, wherein a first temperature of said sealing face adjacent to said protrusion is higher than a second temperature of said sealing face at a distance from said protrusion; (c) closing said jaws to press said layers of film between said sealing face of said heat-sealing element and said backing jaw, and, to simultaneously clamp said film at a location adjacent to said sealing face; (d) holding said jaws closed for a period of time required to form said sealed portion and said notch; and (e) opening said jaws to release said layers of film.