US3800057A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrically heated furnace utilizing ceramic heating elements
Assignee: Preussag AG
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Filing: 1973-07-09
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Granted: 1974-03-26
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Expires: 1993-07-09
Abstract
Abstract An electrically heated furnace utilizing ceramic heating elements. The heating elements are series-connected across a spark gap and take on a variety of different configurations depending on their specific application.
Inventors
- 👤 Schafer W Kuhlmann
- 👤 K Hagen
- 👤 H Peters
- 👤 G Wolters
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:51
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/62; H05B3/10; H05B3/12; H05B3/14; H05B3/141; Y; Y10; Y10S; Y10S65/00; Y10S65/04
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
32 words
In an electrically heated furnace, heating means comprising: a first ceramic heat element; and a second ceramic heat element connected in series across a spark gap with said first ceramic heat element.
Claim 2
Dependent Claim
32 words
In an electrically heated furnace, heating means comprising: a first ceramic heat element; and a second ceramic heat element connected in series across a spark gap with said first ceramic heat element.
Claim 3
Dependent Claim
24 words
The invention as set forth in claim 1 wherein said spark gap is formed by superimposed parts of said first and second heat elements.
Claim 4
Dependent Claim
22 words
The invention as set forth in claim 2 wherein said superimposed parts of said first and second heat elements have roughened surfaces.
Claim 5
Dependent Claim
18 words
The invention as set forth in claim 1 wherein said first and second heat elements are elongated bars.
Claim 6
Dependent Claim
17 words
The invention as set forth in claim 4 wherein said bars are substantially rectangular in cross-sectional shape.
Claim 7
Dependent Claim
55 words
The invention as set forth in claim 4 wherein said heat elements are curved to form semi-rings, said semi-rings being connected to form a coil-shaped furnace with one semi-ring resting upon and partially overlapping another semi-ring wherein the concave portions of said rings face one another and including installing range spacers connected between individual semi-rings.
Claim 8
Dependent Claim
38 words
The invention as set forth in claim 4 wherein said heat elements form semi-rings and are connected in series with the front face of one ring contacting the front face of the adjacent ring to form a coil.
Claim 9
Dependent Claim
66 words
In an electrically heated furnace, heating means comprising: a plurality of bar-shaped ceramic heating elements, each of said heating elements being connected to another of said heating elements in series across a spark gap, said heating elements being stacked one on top of another, and including conductive connecting members of ceramic material located between adjacent pairs of said heating elements to space apart said heating elements.
Claim 10
Dependent Claim
66 words
In an electrically heated furnace, heating means comprising: a plurality of bar-shaped ceramic heating elements, each of said heating elements being connected to another of said heating elements in series across a spark gap, said heating elements being stacked one on top of another, and including conductive connecting members of ceramic material located between adjacent pairs of said heating elements to space apart said heating elements.
Claim 11
Dependent Claim
27 words
The invention as set forth in claim 8 wherein each of said connecting members is integral with an adjoining heat element to form a substantially L-shaped element.
Claim 12
Dependent Claim
20 words
The invention as set forth in claim 8 including insulating range spacers adapted to space apart said L-shaped heating elements.
Claim 13
Dependent Claim
51 words
In an electrically heated furnace, heating means comprising: a plurality of bar-shaped ceramic heating elements bent in the shape of semi-rings, said heating elements being stacked on top of one another in coil-shaped fashion, partially overlapping one another, and including range spacers adapted to space adjacent pairs of said semi-rings apart.
Claim 14
Dependent Claim
51 words
In an electrically heated furnace, heating means comprising: a plurality of bar-shaped ceramic heating elements bent in the shape of semi-rings, said heating elements being stacked on top of one another in coil-shaped fashion, partially overlapping one another, and including range spacers adapted to space adjacent pairs of said semi-rings apart.
Claim 15
Dependent Claim
55 words
The invention as set forth in claim 11 wherein said range spacers are substantially U-shaped, each of said spacers being comprised of two legs and a connecting cross-part to form said U-shape, wherein said range spacers are connected between said heating elements with the cross-part of each of said spacers extending away from the furnace.
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) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |