| 摘要 |
555,131. Apparatus for making artificial filaments &c. DU PONT DE NEMOURS & CO., E. I. Feb. 2, 1942, No. 1346. Convention date, Nov. 30, 1940. [Class 2 (ii)] [Also in Groups V and XXX] . A composite vertical extruding screw comprises a feeding segment 5, a melting segment 10 and a metering segment 11, the feeding and metering segments being composed of a metal having a low heattransfer coefficient, such as stainless steel, and the melting segment being composed of a metal having a high heattransfer coefficient, such as machine steel. With this arrangement, the material being extruded (synthetic resins, cellulose derivatives) is heated abruptly and melted sharply on passing from the feeding segment into the meltsegment at 8, and this effect is enhanced by the provision of insulating rings 14 at the juncture, whereby undue cooling of the material by conduction of heat through the screw is prevented. The extrusion chamber is surrounded by a heating jacket 9 filled with a mixture of diphenyl and diphenyl oxide vapours. A heating unit, e.g. an electric resistance, may be disposed in the segment 10. To ensure an even flow of material into the melting zone, the screw segment 5 is interrupted at 6. To avoid excessively high pressures in the melting zone, grooves 7a are formed in the bushing surrounding the segment 5. The segment 10 may be, cylindrical or, as shown, tapered. The extrusion chamber may terminate in a spinneret for spinning textile fibres or may be used for extrusion of bristles or for casting films. |
