摘要 |
<p>A heat sealing device for use in the high speed heating sealing of webs of thermally softenable material. Heating elements (12a) are provided on carriers (12) spanning two endless chains (10). Pressure elements (23) spanning another pair of endless chains co-act with the heating elements so that the latter apply heat and pressure to the webs for an extended period as the webs travel through the device. The temperature to which the heating elements are heated is controlled in accordance with the temperature of the heat sealed material leaving the device.</p> |