| 摘要 |
<p>A welding jaw, for thermoplastic films or similar materials, has one or more electric heating elements which are energised in impulses via a switch; in the initial phase of energising (or re-energising), the elements are fed with many times the thermal energy required in ultimate thermal equilibrium between them and their surrounding environment. Arrangement functions effectively een when first used or after an interruption in service.</p> |
