| 摘要 |
The device (2) for changing the outside coating color of the extruded product is seated directly in the extrusion head (1), thus minimizing the length of the duct (25) in which the colored extrudates would be liable to mix; on the other hand, since no colored extrudate can stagnate upstream from that duct, the colored coating is always composed of freshly extruded material. Thus, the transition from one color to another is extremely short on the finished product, so that no faulty material is to be found on that product. The color changing device is essentially composed of an axially movable needle-valve (24) which can be actuated by various means. Through design modifications of this needle-valve, a two-color coating can be produced. An extrusion head equipped with such a device is particularly well adapted to the solid or expanded insulation of electric conductors, although other types of extruded objects can also be produced according to the same principle.
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