| 摘要 |
<p>Electric heating cartridge for producing very hot air, esp. in a hot-air blower for softening thermoplastics, comprises >=2 ceramic bodies fitted with suitable heating-wire circuits and mounted in an air stream, one behind the other. Heating-wire coils are adjuste w.r.t. one another in such a way that relatively large sections of them will reach glowing temp. at a pre-determined airflow rate. Arrangement eliminates the prior disadvantages where incoming cold air cools the heating coils to such an extent that only insufficient heating is attained by the time the air issues at the other end. Choice of length and gauge of heating wires enables efficiency to be improves so that between 2/3 and 3/3 of the length of the coils reaches glowing temp.</p> |
