Form, fill and seal machine with hot gas and thermal impulse sealing

In a form, fill and seal machine in which a web of thermally sealable material is drawn over a tube former to bring the opposite longitudinal edges of the web together in adjacent relationship and a longitudinal sealing mechanism welds the opposite edges together to form a tube from the web, the machine having loading means for discharging measured quantities of a product into the formed tube, an improved sealing apparatus to periodically clamp the tube walls together and thermally form transverse seals across the tube at each side of a line of severance whereby individual sealed packages containing the product can be produced comprising:

• a pair of cooperating sealing heads disposed on opposite sides of the formed tube and mounted for relative movement toward and away from each other to clamp the tube along a transverse section of the tube containing the line of severance, the one of the sealing heads having means for discharging a hot gas onto one side of a transverse sealing area of the tube adjacent the line of severance to press the sealing area uniformly against the other of the sealing heads as a "free form" clamp, and the other of the sealing heads having electrical heating means disposed on the side of said transverse sealing area opposite from the means for discharging a hot gas for heating the pressed area to a fusing temperature in cooperation with the means for discharging a hot gas so that said sealing area is pressed between said hot gas and said electrical heating means.