| 摘要 |
<p>A tubular electrical heating element with radially inwards-directed radiation comprises a spiral heating coil [1] embedded in insulating material, and surrounded on the outside by a thermally insulating layer [3], made from ceramic material or ceramic fibre. The coils may abut or be spaced apart. There is also a mesh-like sleeve [4] between the coil and the thermal insulating layer, and this too is made from ceramic or ceramic fibre. The heating element is a component of a heated nozzle for a pressure-casting or extrusion-casting device and the element is surrounded by a protective tube forming the nozzle sleeve.</p> |
