| 摘要 |
<p>The tubular water heating device (1) has and inner metal conduit (10), an outer conduit (15) substantially surrounding said inner conduit, and electro-resistive heating element (12) disposed adjacent an outer surface of said inner conduit for transferring thermal energy to fluid contained in the inner chamber (11) and outer chamber (16), a continuous metal sheath (13) covering the heating element and forming a monolithic heating tube (14).</p> |
