US3875476A
Expired / Lapsed
US
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Igniter element
Assignee: Honeywell Inc
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Filing: 1974-01-10
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Granted: 1975-04-01
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Expires: 1994-01-10
Abstract
Abstract A heat-resistant ceramic electric igniter element has a plurality of compositions in a continuous unitary body structure including a central or igniting zone of a composition having a relatively high electrical resistance flanked by end zones of a composition having a lower electrical resistance to which the leads are attached. Gradual transitions from one composition to the other are provided which compensate for any differences in the coefficient of expansion between the two compositions and minimize migration between the two compositions.
Inventors
- 👤 William B Crandall
- 👤 Linden E Shipley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:12
CPC Classifications
F; F23; F23Q; F23Q7/00; F23Q7/22; H; H01; H01C; H01C7/00; H01C7/02
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
105 words
A CONTINUOUS UNITARY BODY FORMED IN A SINGLE SEGMENT, SAID BODY CONTAINING A PLURALITY OF HEAT AND OXIDATION RESISTENT, ELECTRICALLY CONDUCTIVE CERAMIC MATERIAL COMPOSITIONS WHEREIN SAID COMPOSITIONS COMPRISE: AN IGNITING ZONE HAVING A COMPOSITION EXHIBITING A RELATIVELY HIGH ELECTRICAL RESISTANCE; ZONES FLANKING SAID IGNITING ZONE, SAID FLANKING ZONES HAVING A COMPOSITION EXHIBITING A LOWER ELECTRICAL RESISTANCE THAN SAID IGNITING ZONE; WHEREIN THE COMPOSITIONAL TRANSITION BETWEEN SAID IGNITING ZONE AND SAID FLANKING ZONE IS A GRADUAL TRANSITION; AND WHEREIN SAID COMPOSITIONS OF BOTH SAID IGNITING ZONE AND SAID FLANKING ZONES COMPRISE PRINCIPLY OF SILICON CABRIDE AND PYERX-TYPE CLASS; AND ELECTRICAL LEADS ATTACHED TO SAID FLANKING ZONES.
Claim 2
Dependent Claim
105 words
A CONTINUOUS UNITARY BODY FORMED IN A SINGLE SEGMENT, SAID BODY CONTAINING A PLURALITY OF HEAT AND OXIDATION RESISTENT, ELECTRICALLY CONDUCTIVE CERAMIC MATERIAL COMPOSITIONS WHEREIN SAID COMPOSITIONS COMPRISE: AN IGNITING ZONE HAVING A COMPOSITION EXHIBITING A RELATIVELY HIGH ELECTRICAL RESISTANCE; ZONES FLANKING SAID IGNITING ZONE, SAID FLANKING ZONES HAVING A COMPOSITION EXHIBITING A LOWER ELECTRICAL RESISTANCE THAN SAID IGNITING ZONE; WHEREIN THE COMPOSITIONAL TRANSITION BETWEEN SAID IGNITING ZONE AND SAID FLANKING ZONE IS A GRADUAL TRANSITION; AND WHEREIN SAID COMPOSITIONS OF BOTH SAID IGNITING ZONE AND SAID FLANKING ZONES COMPRISE PRINCIPLY OF SILICON CABRIDE AND PYERX-TYPE CLASS; AND ELECTRICAL LEADS ATTACHED TO SAID FLANKING ZONES.
Claim 3
Dependent Claim
32 words
The continuous unitary body of claim 1 wherein said ignition zone has a negative temperature coefficient of electrical resistance and wherein said flanking zones have a positive temperature coefficient of electrical resistance.
Claim 4
Dependent Claim
117 words
The continuous unitary body of claim 1 wherein said ignition zone comprises: from about 25 to about 88 percent silicon carbide, from about 1 to about 8 percent ferro-silicon, from about 1 to about 30 percent of oxides from a group consisting of oxides of titianium and zirconium, from about 5 percent to about 30 percent of a pyrex-type glass and from about 5 percent to about 30 percent silica; and wherein said flanking zones comprise: from about 40 percent to about 75 percent silicon carbide, from about 1 percent to about 10 percent ferro-silicon, from about 1 percent to about 20 percent titianium dioxide and from about 5 percent to about 30 percent of pyrex-type glass.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-31 | 1978-09-30 | 1979-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-31 | 1982-09-30 | 1983-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-31 | 1986-09-30 | 1987-04-01 | $7700.00 | Window Closed / Lapsed |