Claims
- 1. A method of heating a quantity of water within a storage container, comprising:
providing a storage container having a storage capacity of at least one gallon, said storage container containing a substantially renewable supply of water, said storage container having a water inlet and a water outlet; said water containing calcium, calcium carbonate, or both, in solution in a sufficient concentration to form a scale deposit during the heating of said quantity of water; said storage container also including an electrical resistance immersion heating element disposed therein; said immersion heating element including a resistance heating material disposed within an electrically insulating, substantially water impervious sheath; said immersion heating element having an active element portion having a watt density of no greater than about 60 W/in2, an overall wattage rating of at least about 1000 W, and capable of fitting within an envelope of no greater than about 50 in3; electrically activating said immersion heating element above 1000 W to heat said water above ambient temperature sufficient to begin the formation of said scale deposit; said immersion heating element substantially reducing the growth of said scale in said storage container.
- 2. The method of claim 1 wherein said active element portion comprises a spiral or coil which permits the free circulation of water over its surface.
- 3. The method of claim 1 wherein said active element portion has a diameter of less than about 0.25 inches.
- 4. The method of claim 1 wherein said electrically activating step activates said immersion heating element to about 2500-4500 W.
- 5. The method of claim 1 wherein said immersion heating element substantially reduces the growth of said scale in said storage tank, generating at least 10 wt. % less scale than a metal tubular element having a 0.315 in. diameter metal sheath and an equivalent envelope.
- 6. The method of claim 5 wherein said active element portion comprises a polymeric-coated wire.
- 7. The method of claim 1 wherein said active element portion is capable of fitting within an envelope of no greater than about 30 in.3
- 8. The method of claim 1 wherein said active element portion comprises a watt density of about 10-40 W/in2.
- 9. The method of claim 1 wherein said active element portion comprise at least a pair of layered coils made from a coated resistance wire.
- 10. In combination, a storage container capable of holding at least one gallon and an electrical resistance immersion heating element for heating water, comprising:
a storage container having contained therein a substantially renewable supply of water, said water containing calcium, calcium carbonate, or both, in a sufficient concentration to form a scale deposit during the heating of said water; an electrical resistance immersion heating element mounted through a wall of said storage container, said electrical resistance immersion heating element including a resistance heating material disposed within an electrically insulating, substantially water impervious sheath to form an active element portion; said active element portion having a cross-sectional dimension of no greater than about 0.25 inches (6.35 mm); and having a watt density of no greater than about 60 W/in2, while providing a total wattage rating of at least about 2500-4500 W; said active element portion being capable of fitting within an envelope of about 50 in3, and substantially reducing the growth of scale in said storage container.
- 11. The combination of claim 10 wherein said active element portion comprises a watt density of no greater than about 10-40 W/in2.
- 12. The combination of claim 10 wherein said active element portion comprises a Ni-Cr alloy wire coated with a fluorocarbon-based polymer.
- 13. The combination of claim 10 wherein said active element portion is capable of fitting within an envelope of less than 30 in3, and can be inserted through a sidewall opening in said storage container of about 1.0-1.5 in diameter.
- 14. The combination of claim 10 wherein said immersion heating element further comprises temperature control means for controlling electrical current through said element.
- 15. A resistance heating element comprising:
a resistance heating material; an electrically insulating, substantially water impervious sheath disposed over said resistance heating material to form an active element portion; a pair of terminal ends extending from said resistance heating material for connecting said resistance heating element to an external source of electrical power; said active element portion defining an envelope having an envelope length less than 30 in. and a cross-sectional envelope dimension of less than 1.5 in.; said active element portion capable of generating a total wattage of at least about 1000 W and having a watt density of no greater than 60 W/in2; said active element portion capable of substantially reducing scale production in water containing calcium, calcium carbonate, or both.
- 16. The resistance heating element of claim 15 wherein said active element portion comprises a polymeric-coated wire or a tubular configuration.
- 17. The heating element of claim 16 wherein said polymeric-coated wire or tubular configuration has an outer diameter of less than about 0.25 in.
- 18. The heating element of claim 16 wherein said active element portion becomes self-limiting with respect to further temperature increases due to scale growth at a wire temperature of about 400° F.
- 19. The heating element of claim 15 wherein said active element portion has a watt density of 10-40 watts/in2.
- 20. The heating element of claim 15 wherein said active element portion comprises a resistance heating wire coated with a fluorocarbon-based polymer, having a watt density of no greater than about 20-35 watts/in2 and an outer diameter of no greater than about 0.125 in.
- 21. A water heater comprising:
a storage container wall comprising a thermally conductive, water impervious polymeric material; an electrical resistance heating element disposed within said storage container wall, said electrical resistance heating element including a resistance heating material which is electrically insulated from the contents of said storage container; said electrical resistance heating element including an active element portion having a watt density of no greater than about 60 W/in2 while providing a total wattage rating of at least about 1,000 watts; said active element portion being capable of substantially reducing the growth of scale in said storage container.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation-in-part of U.S. application Ser. No. 09/756,162, filed on Jan. 8, 2001, and entitled “Flexible Spirally Shaped Heating Element,” and is related to U.S. application Ser. No. 09/275,161 filed Mar. 24, 1999, which is a continuation in part of U.S. application Ser. No. 08/767,156 filed on Dec. 16, 1996, now U.S. Pat. No. 5,930,459, issued on Jul. 27, 1999, which in turn is a continuation in part of U.S. application Ser. No. 365,920, filed Dec. 29, 1994, now U.S. Pat. No. 5,586,214, issued on Dec. 17, 1996, which are all hereby incorporated by reference.
[0002] This application is also related to U.S. application Ser. No. 09/309,429, filed May 11, 1999, U.S. application Ser. No. 09/369,779, filed Aug. 6, 1999, and U.S. application Ser. No. 09/416,371, filed Oct. 13, 1999, which are also hereby incorporated by reference.
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
09756162 |
Jan 2001 |
US |
Child |
09908863 |
Jul 2001 |
US |