| 摘要 |
A method and device for heat sealing thermoplastic materials is disclosed. A pair of flat resistance wires are encased within a plastic sheath and arranged in parallel with their flat surfaces lying in one plane. The wires are spaced from each other in a manner designed for maximum thermal emission. To weld together two thermoplastic materials, the sheathed wires are held between and in firm contact with the materials to be joined. A predetermined electric current is passed through the wires until enough heat has been generated to weld the materials together. The invention may also be applied to a process for heat sealing plastic lids to plastic drums. In particular, the sheathed wires are fastened to the lower surface of a thermoplastic drum lid. The lid, together with the resistance wires is clamped to a thermoplastic drum with a standard drum clamp. An electric current is passed through the wires for a period of time sufficient to heat up the wires and weld the lid to the drum. |
