| 摘要 |
<p>The heater, especially for vaporising liquids such as propane and butane has a heated tubular sleeve through which the medium being heated flows. The metal sleeve is constructed as an ohmic resistance and connected directly to both poles of a voltage source. The voltage source is formed by the ends of the secondary winding of a transformer whose primary receives an ac voltage. Alternatively, the metal sleeve forms the short-circuited secondary winding of a transformer whose primary receives an ac voltage. The advantage lies in high efficiency, fast response little maintenance, long life and low fabrication costs.</p> |
