Patent US3792233A successfully refreshed from Google Patents.
US3792233A
Expired / Lapsed
US
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Heating element
Assignee: Bpifrance Financement SA
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Filing: 1972-05-17
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Granted: 1974-02-12
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Expires: 1992-05-17
Abstract
Abstract The heating element is formed of refractory material resistant to oxidation, in the general shape of a parallelepiped. It has, in a direction perpendicular to two opposite surfaces, a nonhomogeneous structure such that when one of the two surfaces concerned is brought to a sufficiently high temperature to become electrically conducting, the other remains at a sufficiently low temperature to be thermally and electrically practically nonconducting. The structure is adapted to withstand movements due to differences in expansion. The element is made either of entirely or partially stabilized zirconia or of a definite compound of the pyrochlore type based on zirconia, of the formula Zr2T2O5, T being a metal, especially a rare earth. It has holes and cut-outs formed in the mass of the element in a direction substantially perpendicular to that which unites said two opposite surfaces. The ratio hollow/solid is within a range of about 0.1 to 3.
Inventors
- 👤 A Anthony
- 👤 K Dembinski
- 👤 L Dupont
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 20:25
CPC Classifications
B; B01; B01L; B01L7/00; B01L7/54; H; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/141
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
156 words
Heating element formed of refractory material resistant to oxidation, in the general shape of a parallelepiped, adapted to be heated by electric current supplied through electric contacts cladding said element, and having in a direction perpendicular to two of its opposite surfaces, a nonhomogeneous structure such that when one of said two surfaces is brought to a sufficiently high temperature by said electric current to become electrically conducting, the other remains at a sufficiently low temperature to be thermally and electrically practically non-conducting, said structure being adapted to withstand movements due to differences in expansion, constructed of at least partially stabilized zirconia, comprising holes and cut-outs formed in the mass of the element in a directIon substantially perpendicular to that which unites said two opposite surfaces of which one is intended to be brought to a sufficient temperature to become electrically conducting, the ratio hollow/solid being selected in a range of about 0.1 to about 3.
Claim 2
Dependent Claim
16 words
Heating element according to claim 2, wherein the ratio hollow/solid is in the vicinity of unity.
Claim 3
Dependent Claim
83 words
Heating element according to claim 2, wherein the shape and the distribution of the holes and cut-outs are such that, on one hand the two opposite surfaces of which one must be brought to a sufficient temperature to be electrically conducting are connected to one another by portions of relatively slight cross-section and that, on the other hand, the electric current is obliged to pass through the surface of which the temperature is brought to a sufficient value for it to become conducting.
Claim 4
Dependent Claim
35 words
Heating element according to claim 4, wherein the distribution of the holes and cut-outs is selected so that the temperature reached by the surface through which the electric current passes is progressive along this surface.
Claim 5
Dependent Claim
35 words
Heating element according to claim 4, wherein the distribution of the holes and cut-outs is selected to that the temperature reached by the surface through which the electric current passes is uniform along this surface.
Claim 6
Dependent Claim
137 words
Heating element according to claim 1, wherein its ratio hollow/solid is in the vicinity of the lower limit of the range from 0.1 to 3 and comprising: cut-outs of general orientation parallel to the heating surface, these cut-outs being connected to the nonheating surface by cut-outs of the general direction perpendicular to the heating surface, certain of the perpendicular cut-outs comprising a portion inclined at about 45* and dividing the element into several parts; cut-outs of direction perpendicular to the heating surface and situated in the mass of the element between the cut-outs parallel to the heating surface, on the one hand, and the nonheating surface, on the other hand; cut-outs perpendicular to the heating surface and opening on the latter in the neighborhood of the ends of the element; and hollows opening on the nonheating surface.
Claim 7
Dependent Claim
155 words
Heating element formed of refractory material resistant to oxidation, in the general shape of a parallelepiped, adapted to be heated by electric current supplied through electric contacts cladding said element, and having in a direction perpendicular to two of its opposite surfaces, a non-homogeneous structure such that when one of said two surfaces is brought to a sufficiently high temperature by said electric current to become electrically conducting, the other remains at a sufficiently low temperature to be thermally and electrically practically non-conducting, said structure being adapted to withstand movements due to differences in expansion wherein along a direction substantially perpendicular to the assembly of the two opposite surfaces of which one is intended to conduct the electric current, the said element comprises successively a first part with a slight porosity, less than 10 percent, comprising the surface intended to become electrically conducting, and a second part with a high porosity, greater than 30 percent.
Claim 8
Dependent Claim
55 words
Heating element according to claim 8, wherein the first part is formed of stabilized zirconia of density of the neighborhood of 4.5 and that the second part is formed of one of the materials comprising zirconia, eutectic zirconia - Al2O3 and alumina alone, the density of this second part being in the vicinity of 2.
Claim 9
Dependent Claim
24 words
Heating element according to claim 9, wherein the first part comprises a section decreasing in the direction of the length of the heating element.
Claim 10
Dependent Claim
38 words
Heating element according to claim 1, wherein the surface through the electric current passes is divided into lamellae, parallel to one another, by cut-outs perpendicular to the said surface in the direction of the length of thE element.
Claim 11
Dependent Claim
29 words
Heating element according to claim 1, wherein the heating surface comprises hollows giving it a T and U structure, along a section perpendicular to the direction of the length.
Claim 12
Dependent Claim
81 words
Heating element according to claim 1, formed of a definite compound of the pyrochlore type based on zirconia, of the formula Zr2T2O5, where T is a metal, comprising holes and cut-outs formed in the mass of the element in a direction substantially perpendicular to that which unites said two opposite surfaces of which one is intended to be brought to a sufficient temperature to become electrically conducting, the ratio hollow/solid being selected in a range of about 0.1 to about 3.
Claim 13
Dependent Claim
14 words
Heating element according to claim 13, wherein said metal is a rare earth metal.
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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |