| 摘要 |
<p>Extruded and blown plastic film process is monitored and controlled according to film temp. at a point between the extrusion die and the frost line. A signal form a temp. sensor is compared with a datum. The error signal is used to control cooling of the film. Used e.g. for a revolving tube type process. The control compensates for cyclic variations which can arise e.g. variation of melt index and melt temp. conditions in cooling system, gradual clogging of filter. A useful increase in prodn. rate is obt. without adverse effect on quality, or better quality without increased rate.</p> |
