| 摘要 |
<p>1478106 Mixing apparatus E BECK 21 Oct 1975 [22 Oct 1974] 43224/75 Heading B1C [Also in Divisions B4 and B5] A high-speed autogenous, or adiabatic extruder, comprises a screw shaft 12 having a pair of threads 11, each of which delivers thermoplastics from one inlet 1, of a pair located at opposite ends of the shaft 12, to an outlet 4 intermediate the ends of the shaft. To enable the shaft to be rotated only at one end, at a pulley 13, the overall length/diameter ratio of the threads of the shaft is equal to or less than 28:1 and preferably a maximum of 20:1. the thread depth in the metering zone of the threads is equal to or less than 1:20 of the diameter of the screw threads and preferably a maximum of 1.25; and the peripheral speed of the threads is equal to or less than 0.3 metres per second. To compensate for viscosity differences between the thermoplastics discharged by the threads 11, the extruder may discharge into a static mixer or, as described, each thread 11 may discharge at a semi-circular opening 4 into a die from which is extruded, by means of a deflector, a section comprising a core 5 of material discharged from one thread, surrounded circumferentially by a layer 6 of the same, or a different, material discharged from the other thread.</p> |
