| 摘要 |
The heating cable comprises at least one bare resistance heating conductor arranged on a flexible core (4) and an insulation which surrounds the core (4) together with the heating conductor. The heating cable (1) has a predetermined length with a heating conductor section (2) and at least one PTC thermistor section (3) which merges continuously into said heating conductor section. The core (4) is produced as a flexible plastic strand (4a) in the region of the heating conductor section (2), and as a litz wire (4b), made from wires which are good conductors of electricity, in the region of each of the PTC thermistor sections (3) which feed and remove current. Each end of the plastic strand part (4a) is permanently firmly connected to the relevant litz wire part (4b) of the core (4) by means of at least one ferrule (11). The maximum cross-sectional dimension of the ferrule (11) in the compressed state is approximately equal to that of the unpressed core (4). The heating conductor and the insulation (9) extend over the entire length of the heating cable (1), including each PTC thermistor section (3). Breakage of conductors and damage to insulation, as well as breakdowns in the connecting region between the current-feeding PTC thermistor (3) and the actual heating cable are reliably prevented. Continuous and trouble-free operation of a heating element fitted with the heating cable is very reliably guaranteed. <IMAGE>
|
