| 摘要 |
The heating apparatus comprises metal heating shells (shells 14) each with a single cast-in heating element, which is shaped from a linear pipe to form at least one loop (13). The heating element has supporting faces (13e) which are not covered by the cast metal and on which clearances (14e, 14f) starting from the inner and outer circumferential surface of the shell (14) open out. Such a design achieves the effect that the metal shells can be produced with considerably smaller wall thickness by the pressure diecasting process using relatively high injection pressures. The small wall thickness allows the contact faces (14g) to bear fully against the plasticising cylinder and thus allows more rapid heating (Figs. 7, 7a, 7b). |
