| 摘要 |
An extrusion die for two-ply seamless plastic tubing, includes an extrusion head with a first nozzle provided with a first centering means; a first hollow mandrel placed within said nozzle; an elongate carrier bearing a second mandrel, a second nozzle and a spider in turn supporting a distributor splitting an extrudate. The first nozzle and the distributor define a first annular extrusion orifice for an outer parison of the tubing while the second nozzle and the second mandrel define a second annular extrusion orifice for the inner parison of the tubing. A threaded member longitudinally adjusts said carrier to vary the size of the first extrusion orifice. A coupling means interconnects the carrier and the first mandrel and allows only the axial, without rotation, movement of the carrier. A second centering means mounts the distributor uniformly spaced around the spider. |
