Ceramic igniter
View Patent ↗New ceramic resistive igniter elements are provided that comprise a first conductive zone, a resistive hot zone, and a second conductive zone, all in electrical sequence. In preferred igniters, at least a substantial portion of the first conductive zone does not contact a ceramic insulator. Preferred igniters of the invention have a rounded cross-sectional shape for at least a portion of the igniter length.
1. A ceramic igniter having a rounded cross-sectional shape for at least a portion of the igniter length, the igniter comprising:
in electrical sequence, a first conductive zone, a resistive hot zone, and a second conductive zone,
a void region interposed between the first and second conductive zones along at least a substantial portion of the lengths of first and second conductive zones, wherein at least a substantial portion of the first conductive zone length does not contact a ceramic insulator and the igniter has a rounded cross-sectional shape for at least a portion of the igniter length.
2. The ceramic igniter of claim 1 wherein the igniter has a substantially constant width for at least a substantial portion of the igniter length.
3. The ceramic igniter of claim 1 wherein the igniter width in a region comprising the first and second conductive zones is greater than the igniter width in a region comprising the hot zone.
4. The ceramic igniter of claim 3 wherein the igniter width in the conductive zones region is at least about three times greater than the igniter width in a the hot zone region.
5. The ceramic igniter of claim 1 wherein the first conductive zone is at least partially encased within the second conductive zone.
6. The ceramic igniter of claim 1 wherein the igniter has a substantially circular cross-sectional shape.
7. The ceramic igniter of claim 1 wherein the first conductive zone and second conductive zone mate with opposing ends of the hot zone.
8. The ceramic igniter of claim 1 wherein the igniter electrical pathway extends in sequence through the first conductive zone, the hot zone, and the second conductive zone.
9. The ceramic igniter of claim 1 wherein the igniter does not contain a ceramic insulator region.
10. A ceramic igniter comprising:
in electrical sequence, a first conductive zone, a resistive hot zone, and a second conductive zone,
wherein the second conductive zone substantially encases the first conductive zone, wherein at least a substantial portion of the first conductive zone length does not contact a ceramic insulator, and the igniter has a rounded cross-sectional shape for at least a portion of the igniter length.
11. The ceramic igniter of claim 10 wherein a void region is interposed between at least a portion of the lengths of the first and conductive zones.
12. The igniter of claim 1 wherein the igniter has a substantially circular cross-sectional shape for at least about 40 percent of the igniter length.
13. The igniter of claim 1 wherein the igniter has a substantially circular cross-sectional shape for at least about 60 percent of the igniter length.
14. The igniter of claim 1 wherein the igniter has a substantially circular cross-sectional shape for at least about 90 percent of the igniter length.
15. The igniter of claim 10 wherein the igniter has a substantially circular cross-sectional shape for the entire igniter length.
16. The igniter of claim 10 wherein the igniter has a substantially circular cross-sectional shape for at least about 40 percent of the igniter length.
17. The igniter of claim 10 wherein the igniter has a substantially circular cross-sectional shape for at least about 60 percent of the igniter length.
18. The igniter of claim 10 wherein the igniter has a substantially circular cross-sectional shape for at least about 90 percent of the igniter length.
19. The igniter of claim 10 wherein the igniter has a substantially circular cross-sectional shape for the entire igniter length.
20. The igniter of claim 1 wherein the substantial portion is at least about 60%.
21. The igniter of claim 1 wherein the substantial portion at least 70%.
22. The igniter of claim 1 wherein the substantial portion is at least 80%.
23. The igniter of claim 1 wherein the substantial portion at least 90%.
24. A ceramic igniter comprising:
in electrical sequence, a first conductive zone, a resistive hot zone, and a second conductive zone,
the second conductive zone substantially encasing the first conductive zone,
a void region interposed between the first and second conductive zones along at least a substantial portion of the lengths of first and second conductive zones,
wherein at least a substantial portion of the first conductive zone length does not contact a ceramic insulator.
25. The igniter of claim 24 wherein the igniter has a substantially circular cross-sectional shape for at least about 40 percent of the igniter length.
26. The igniter of claim 24 wherein the igniter has a substantially circular cross-sectional shape for at least about 60 percent of the igniter length.
27. The igniter of claim 24 wherein the igniter has a substantially circular cross-sectional shape for at least about 90 percent of the igniter length.
28. The igniter of claim 24 wherein the igniter has a substantially circular cross-sectional shape for the entire igniter length.
29. The igniter of claim 24 wherein the substantial portion is at least 60%.
30. The igniter of claim 24 wherein the substantial portion is at least 70%.
31. The igniter of claim 24 wherein the substantial portion is at least 80%.
32. The igniter of claim 24 wherein the substantial portion is at least 90%.
33. The igniter of claim 24 wherein the igniter is adapted for use with line voltages in excess of 24 volts.