| 摘要 |
<p>A device (D) for welding together the overlapping ends of two sheet materials is described. The welding cheek has a relief pattern formed in the working face and presses against one side of the two materials to be welded. On the other side of the materials is a corresp. plate against which the cheek can be pressed. The pattern is formed of bars which cross each other and create raised sections together with corresp. recesses between them. The total volumea of the recesses formed is sufficiently large to accept and retain the majority of molten material created during the welding operation. USE/ADVANTAGE - (D) can be used for welding together packages formed of one or more thermoplastic layers and containing fluid foodstuffs. (D) produces a durable weld between the overlapping layers of plastic. (D) exerts equal pressure over the whole surface and produces uniform heat distribution. Improved stiffness of the welded joint is obtained by retention of molten material under the welding cheek.</p> |
