| 摘要 |
The present invention provides immersion heating elements, water heaters and methods for their fabrication and use. In the first embodiment of this invention, a resistance heating element is provided which includes a resistance heating material and an electrically insulating, substantially water impervious sheath disposed over the resistance heating material to form an active element portion having an envelope of about 50 in<3>, a total wattage of at least 1000 W, and a watt density of no greater than 60 W/in<2>. Such an element has been demonstrated to substantially reduce scale reduction in water containing calcium, calcium carbonate, or both in solution.
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