Patent US3781528A successfully refreshed from Google Patents.
US3781528A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heat resistant,electrical insulating heating unit
Assignee: Bulten Kanthal AB
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Filing: 1972-05-30
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Granted: 1973-12-25
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Expires: 1992-05-30
Abstract
Abstract A heat resistant electrical insulating unit having a rigid body of a ceramic material and a layer of ceramic fiber web bound to the ceramic body into a single unit. The unit may have several layers of rigid ceramic and fiber web layers with the fiber web layers spaced from each other and having an electrical resistance element interposed between them, the outermost rigid bodies being joined together mechanically or being welded together in such a manner that the fiber web layers and the interposed resistance element are held clamped between the rigid ceramic bodies. A method is also disclosed for making heating elements wherein a resistance heating element and the insulating layer or layers are joined together into an essentially two-dimensional unit and are placed on a flat glass ceram body which has been heated to a welding temperature, and thereafter a second glass ceram body which has been heated up to body temperature is placed upon and pressed against the first-mentioned body in such a manner that the two bodies are welded together and enclose at least the edge portion of the said unit all around the same.
Inventors
- 👤 N Schrewelius
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 16:30
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/68; H05B3/74; H05B3/748; H05B3/20; H05B3/22; H05B3/688
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
108 words
An improvement in electrical resistance heating elements, particularly hot plates and similar heat sources comprising a resistance wire for elevated temperatures, wherein the resistance wire is interposed between two separate insulating layers of ceramic material, at least one of said insulating layers forming a resilient quartz glass fiber web comprising at least about 98% SiO2 for supporting the resistance wire, the two insulating layers and the interposed resistance wire being supported by a unitary rigid body of glass ceram, said unitary body of glass ceram being in one piece and forming a surrounding rigid frame which has been pressed on to the edge portions of the insulating layers.
Claim 2
Dependent Claim
108 words
An improvement in electrical resistance heating elements, particularly hot plates and similar heat sources comprising a resistance wire for elevated temperatures, wherein the resistance wire is interposed between two separate insulating layers of ceramic material, at least one of said insulating layers forming a resilient quartz glass fiber web comprising at least about 98% SiO2 for supporting the resistance wire, the two insulating layers and the interposed resistance wire being supported by a unitary rigid body of glass ceram, said unitary body of glass ceram being in one piece and forming a surrounding rigid frame which has been pressed on to the edge portions of the insulating layers.
Claim 3
Dependent Claim
35 words
An improvement as in claim 1, wherein the resistance wire rests on at least one of the insulating layers through an intermediate layer, which facilitates the movements of the wire in relation to the layer.
Claim 4
Dependent Claim
25 words
An improvement as in claim 2, wherein the intermediate layer consists of a layer of ceramic material of a group consisting of sillimanite and alumina.
Claim 5
Dependent Claim
30 words
An improvement as in claim 2, wherein the intermediate layer consists of slightly spaced rods of a highly temperature resistant material such as sillimanite, arranged transversely to the resistance wire.
Claim 6
Dependent Claim
37 words
An improvement as in claim 2, wherein the intermediate layer is disposed on the surface of the insulating layer facing the resistance wire and a similar layer is disposed on the other side of the insulating layer.
Claim 7
Dependent Claim
101 words
An improvement in electrical resistance heating element, particularly hot plates and similar heat sources comprising a resistance wire for elevated temperatures, the resistance wire being supported by means of a body of glass ceram, said resistance wire being interposed between two insulating layers of ceramic fabric, and being supported by one of said insulating layers which insulating layer and said resistance wire are supported by a surrounding rigid frame which is open at at least one side thereof, said rigid frame comprising a unitary glass frame in one piece, which has been pressed onto the edge portions of the insulating layers.
Claim 8
Dependent Claim
101 words
An improvement in electrical resistance heating element, particularly hot plates and similar heat sources comprising a resistance wire for elevated temperatures, the resistance wire being supported by means of a body of glass ceram, said resistance wire being interposed between two insulating layers of ceramic fabric, and being supported by one of said insulating layers which insulating layer and said resistance wire are supported by a surrounding rigid frame which is open at at least one side thereof, said rigid frame comprising a unitary glass frame in one piece, which has been pressed onto the edge portions of the insulating layers.
Claim 9
Dependent Claim
121 words
An improvement in electrical resistance heating element, particularly hot plates and similar heat sources comprising a resistance wire for elevated temperatures, the resistance wire being supported by means of a body of glass ceram, said resistant wire being interposed between two insulating layers of ceramic fabric, and being supported by one of said insulating layers which insulating layer and said resistance wire are supported by a surrounding rigid frame which is open at at least one side thereof, said resistance wire resting on said insulating layer through an intermediate layer of slightly spaced rods of a highly temperature resistant material such as sillimanite, arranged transversely to the resistance wire, thereby to facilitate movements of the wire in relation to the layer.
Claim 10
Dependent Claim
121 words
An improvement in electrical resistance heating element, particularly hot plates and similar heat sources comprising a resistance wire for elevated temperatures, the resistance wire being supported by means of a body of glass ceram, said resistant wire being interposed between two insulating layers of ceramic fabric, and being supported by one of said insulating layers which insulating layer and said resistance wire are supported by a surrounding rigid frame which is open at at least one side thereof, said resistance wire resting on said insulating layer through an intermediate layer of slightly spaced rods of a highly temperature resistant material such as sillimanite, arranged transversely to the resistance wire, thereby to facilitate movements of the wire in relation to the layer.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |