| 摘要 |
On the inside and outside of the layer (3) of resistance material, electrically conductive wires (1,4) connected to a power source (7) induce heat losses. Around the outside of the material is a protective layer (4,5,6) producing thermic insulation, mechanical and/or humidity protection. The resistant material has a temp.-dependent resistance where heat losses generated within it are reduced when the temp. increases and vice-versa. The tube (1) used for carrying the medium is electrically conductive, or, alternatively, it may be a conductive component on the inner surface of the resistive layer. A further version uses a non-electrically conductive tube on the surface of which is positioned a conductive wire against the inner surface of the layer of resistance material. |
