| 摘要 |
PURPOSE:To improve the durability and thermal efficiency of a nozzle heater by providing plural hollow grooves to a nozzle body in the longitudinal direction thereof and freely attachably and detachably fitting heater cases contg. sheathed heaters into said hollow grooves. CONSTITUTION:The plural longitudinal hollow grooves 6 are circumferentially bored to the cylindrical nozzle body 3 having a passage 2 for a molten metal. The sheathed heaters 8 having exposed terminals are freely attachably and detachably fitted and fixed into the heater cases 7 fitted into such hollow grooves 6 and the terminals are connected to a connecting terminal board 9. The cases 7 are constituted of a heat resisting alloy having the coefft. of thermal expansion equal to the coefft. of thermal expansion of the material forming the nozzle body 3. A heat insulating cylinder 10, a reflecting cylinder 11, and a cover 12 are respectively coated and fixed to the outside of the body 3. The heat conductivity to the nozzle is improved and the overheating of the heaters 7 is prevented by the above-mentioned mechanism. The durability and thermal efficiency of the nozzle heater are thus improved. |
