| 摘要 |
<p>Heat sealing apparatus for packaging machinery and particularly suitable for form, fill and seal packaging machinery. The heat sealing apparatus is for forming a continuous lengthways extending seal (29) on a web (18) of packaging material to be fed past it. The apparatus comprises a nozzle (50) connectable to a hot gas producer (62) which produces a flow of hot gas having a substantially constant temperature. The nozzle is mounted on a carrier (52) which is connected with a servo motor drive (56). The servo motor is controlled by a control system (48) so that in use it moves the nozzle relative to the web in accordance with variations in web feed velocity such that the flow of hot gas from the nozzle can apply a substantially constant heat to the web to form the seal (29). The apparatus allows a hot air producer which outputs hot air at a constant temperature and volume flow rate to apply a constant heat along the seal area despite variations in the web feed speed.</p> |
