| 摘要 |
A compact, inexpensive self-regulating heater for heating a surface to a prescribed temperature. A first embodiment comprises a PTC ceramic heating element which is conductively bonded directly to heavy copper (or brass) electrodes, which conduct both heat and electricity with low resistance and present a smooth, extended heat transfer surface. At least one of the electrodes (on at least one side of the PTC element) is configured for maximum surface area in contact with the article being heated. The preferred methods of manufacture of this invention result in the electrodes being prestressed in tension while the ceramic element is prestressed in compression at room temperature. Upon heating, during use, these stresses tend to disappear as the electrodes expand. A second embodiment comprises a heater tape constructed of multiple modules which are electrically and mechanically connected with bus wires having a bend therein to facilitate the wires being bent in the side to side direction as well as in the up and down direction so that the heater tape can follow an irregular path. The modules are mounted in a flexible rubber skeleton which is sharply necked down between the modules to allow ease of bending in the side-to-side direction as well as in the up and down direction.
|
