US3818181A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tunnel furnace, resistance type
Assignee: Saint Gobain Industries SA
•
Filing: 1971-11-29
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Granted: 1974-06-18
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Expires: 1991-11-29
Abstract
Abstract A tunnel furnace of electrical resistance type comprising means to transport objects which are to be heated through the tunnel, means to heat the objects as they pass through the furnace comprising separate banks of resistances and means to supply each bank with current individually, means to mount each bank in operating position individually, means to remove each mounting means and its bank of resistances individually from the furnace, and means to maintain any remaining banks at operating temperature. A method of controlling the heating of glass moving through a tunnel furnace of electrical resistance type which comprises arranging the resistances in separate gangs separately supplied with current, arresting the movement of the glass when a gang of resistances is to be repaired, sealing off the portions of the tunnel adjacent the gang which is to be repaired, thereby maintaining such portions at operating temperatures, replacing the inefficient gang of resistances, removing such seals, and returning the furnace to operation.
Inventors
- 👤 C Benard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:12
CPC Classifications
C; C03; C03B; C03B29/00; C03B29/04; C03B29/06; C03B29/08; H; H05; H05B; H05B3/00; H05B3/62; H05B3/66
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
178 words
A thermally and electrically insulative tunnel furnace comprising conveyor means to transport objects longitudinally of the tunnel of the furnace and a refractory vault positioned over the conveyor means and forming the ceiling of the furnace, said vault comprising a plurality of separate sections placed in endto-end relation lengthwise of the furnace, each said section including generally horizontal plate means, electrical resistance heating means arranged on said plate means, and a generally vertical side wall piece adjacent each longitudinal edge of said plate means, the side wall pieces of adjacent sections being in close end-to-end relation to form substantially continuous side walls longitudinally of the vault, said vault further comprising for each section a supporting frame and means for individually suspending the plate means and each of the side wall pieces of such section in operative assembly from said frame, each said side wall piece being divided into two parts individually suspended from said frame for vertical adjustment relative to each other in a manner to selectively increase or diminish the effective extent thereof longitudinally of the vault.
Claim 2
Dependent Claim
178 words
A thermally and electrically insulative tunnel furnace comprising conveyor means to transport objects longitudinally of the tunnel of the furnace and a refractory vault positioned over the conveyor means and forming the ceiling of the furnace, said vault comprising a plurality of separate sections placed in endto-end relation lengthwise of the furnace, each said section including generally horizontal plate means, electrical resistance heating means arranged on said plate means, and a generally vertical side wall piece adjacent each longitudinal edge of said plate means, the side wall pieces of adjacent sections being in close end-to-end relation to form substantially continuous side walls longitudinally of the vault, said vault further comprising for each section a supporting frame and means for individually suspending the plate means and each of the side wall pieces of such section in operative assembly from said frame, each said side wall piece being divided into two parts individually suspended from said frame for vertical adjustment relative to each other in a manner to selectively increase or diminish the effective extent thereof longitudinally of the vault.
Claim 3
Dependent Claim
53 words
The combination comprising a tunnel furnace as defined in claim 1, track means extending longitudinally of the furnace, and a crane operable on said track means and operable to engage any of said supporting frames for lifting a section vertically from the vault and transporting the same above and longitudinally of the vault.
Claim 4
Dependent Claim
37 words
A tunnel furnace as defined in claim 1 wherein the plate means of adjacent sections of the vault are longitudinally spaceD, said furnace further comprising means for closing the spaces between adjacent ones of said plate means.
Claim 5
Dependent Claim
25 words
A tunnel furnace as defined in claim 3 wherein said space closing means are readily removable and replaceable when the sections are in assembled relation.
Claim 6
Dependent Claim
44 words
A tunnel furnace according to claim 1 wherein the two parts of each of said side pieces are of generally trapezoidal shape in elevation and are divided along a line inclined to the vertical extending from top to bottom of each said side piece.
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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) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |