US3309643A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric heating element
Assignee: Massachusetts Institute of Technology
•
Filing: 1964-01-02
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Granted: 1967-03-14
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Expires: 1984-01-02
Abstract
No abstract record available.
Inventors
- 👤 Ferretti August
- 👤 Richard W Germann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 21:41
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/68; H05B3/688; H05B3/10; H05B3/12; H05B3/14; H05B3/141; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12014; Y10T428/12021; Y10T428/12028; Y10T428/12146; Y10T428/12486
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
123 words
AN ELECTRIC HEATING ELEMENT COMPRISING: AT LEAST ONE HEATING ZONE OF A PRESELECTED FINELY DIVIDED METAL DISPERSED UNIFORMLY THROUGHOUT A PRESELECTED REFRACTORY INSULATOR; AT LEAST TWO CONDUCTING ZONES OF SIMILAR MATERIAL TO SAID HEATING ZONES BEARING A MUCH HIGHER RATIO OF METAL TO REFRACTORY INSULATOR; SAID HEATING AND CONDUCTING ZONES PREARRANGED TO PROVIDE A SUBSTANTIALLY BROAD UNIFORM HEATING SURFACE THE INTERFACE BETWEEN SAID HEATING AND CONDUCTING ZONES PREARRANGED TO PROVIDE A GRADUAL TRANSITION IN METAL RICHNESS SUCH THAT DESTRUCTIVE THERMAL STRESSES ARE THEREFORE AVOIDED; LEADS FASTENED TO SAID CONDUCTING ZONES; A COATING OF SAID REFRACTORY INSULATOR EXTENDING OVER SAID ENTIRE ELEMENT WITH SAID LEADS PROJECTING THROUGH SAID COATING PROVIDING A STRONG ELECTRICALLY INSULATED SURFACE CAPABLE OF INTIMATE CONTACT WITH VESSELS TO BE HEATED.
Claim 2
Dependent Claim
123 words
AN ELECTRIC HEATING ELEMENT COMPRISING: AT LEAST ONE HEATING ZONE OF A PRESELECTED FINELY DIVIDED METAL DISPERSED UNIFORMLY THROUGHOUT A PRESELECTED REFRACTORY INSULATOR; AT LEAST TWO CONDUCTING ZONES OF SIMILAR MATERIAL TO SAID HEATING ZONES BEARING A MUCH HIGHER RATIO OF METAL TO REFRACTORY INSULATOR; SAID HEATING AND CONDUCTING ZONES PREARRANGED TO PROVIDE A SUBSTANTIALLY BROAD UNIFORM HEATING SURFACE THE INTERFACE BETWEEN SAID HEATING AND CONDUCTING ZONES PREARRANGED TO PROVIDE A GRADUAL TRANSITION IN METAL RICHNESS SUCH THAT DESTRUCTIVE THERMAL STRESSES ARE THEREFORE AVOIDED; LEADS FASTENED TO SAID CONDUCTING ZONES; A COATING OF SAID REFRACTORY INSULATOR EXTENDING OVER SAID ENTIRE ELEMENT WITH SAID LEADS PROJECTING THROUGH SAID COATING PROVIDING A STRONG ELECTRICALLY INSULATED SURFACE CAPABLE OF INTIMATE CONTACT WITH VESSELS TO BE HEATED.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1970-03-13 | 1970-09-12 | 1971-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1974-03-13 | 1974-09-12 | 1975-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1978-03-13 | 1978-09-12 | 1979-03-14 | $7700.00 | Window Closed / Lapsed |