US3607475A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing electrical resistance elements and elements manufactured by the method
Assignee: Kanthal AB
•
Filing: 1967-10-24
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Granted: 1971-09-21
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Expires: 1987-10-24
Abstract
Abstract An electric resistance element of molybdenum disilicide has a thin incandescent zone whose dimensions are formed by chemical decomposition, dissolution or corrosion.
Inventors
- 👤 Nils Gustav Schrewelius
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:04
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/10; H05B3/12; H05B3/14; H05B3/148; C; C23; C23F; C23F1/00; H01; H01B; H01B1/00; H01B1/14; H05B2203/00; H05B2203/018; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49082; Y10T29/49083
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
42 words
A method in accordance with claim 1 in which the step of bringing the chemical agent into contact with said incandescent portion comprises the step of bringing an acid mixture comprising nitric acid and hydrofluoric acid into contact with said incandescent portion.
Claim 2
Dependent Claim
56 words
A method in accordance with claim 2 in which said step of bringing a chemical agent into contact with said incandescent portion comprises the step of bringing an acid mixture consisting essentially of 50 parts by volume of concentrated nitric acid and 50 parts by volume of concentrated hydrofluoric acid into contact with said incandescent portion.
Claim 3
Dependent Claim
44 words
A method in accordance with claim 1 in which said step of bringing said chemical agent into contact with said incandescent portion comprises the step of submerging said incandescent portion into said chemical agent while maintaining said electrode portion free from said chemical agent.
Claim 4
Dependent Claim
58 words
A method in accordance with claim 4 in which said step of forming said electrical resistance blank comprises the step of coating said electrode portion with a masking substance that is not affected by said chemical agent, whereby the interface between the chemical agent and the atmosphere is prevented from creating a discontinuity in said electrical resistance element.
Claim 5
Dependent Claim
45 words
A method in accordance with claim 4 in which said electrical resistance blank is moved with respect to said chemical agent while submerged therein, whereby said interface between said chemical agent and the atmosphere is prevented from causing a discontinuity in said electrical resistance element.
Claim 6
Dependent Claim
49 words
A method according to claim 1 in which said step of forming said electrical resistance blank includes the step of forming said electrical resistance blank from a material consisting of at least 60 percent by volume of molybdenum disilicide and at most 40 percent by volume of ceramic additions.
Claim 7
Dependent Claim
196 words
A method in accordance with claim 1 in which: said step of forming said electrical resistance blank includes the step of forming a straight rod of approximately 5 millimeters in diameter with a porosity less than 1 percent of a fine-grained powder metallurgical body containing 90 percent by weight of molybdenum disilicide and 10 percent by weight of a glass rich in silicone dioxide which has been produced by sintering molybdenum disilicide and bentonite and the step of bending said rod while heated into a U-shape with the legs of the U having a length of approximately 50 millimeters and with a space between the legs of approximately 15 millimeters; said step of bringing a chemical agent into contact with said incandescent portion includes the step of submerging the U-shaped blank half way into a cold mixture of 50 parts by volume of concentrated nitric acid, 50 parts by volume of concentrated hydrofluoric acid and 10 parts by volume of water for approximately two minutes while being moved; and said step of separating said incandescent portion and said chemical agent includes the steps of removing said U-shaped blank from said cold mixture and rinsing with water.
Claim 8
Dependent Claim
32 words
An electrical resistance element formed in accOrdance with the method of claim 1 and having a rodlike cross section in which the diameter of the incandescent zone is less than 6 millimeters.
Claim 9
Dependent Claim
44 words
An electrical resistance element formed in accordance with the method of claim 1 and having a rodlike cross section in which the diameter of the incandescent zone is less than 1 millimeter and the diameter of the electrode portion is more than 1 millimeter.
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) | 1974-09-20 | 1975-03-22 | 1975-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-20 | 1979-03-22 | 1979-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-20 | 1983-03-22 | 1983-09-21 | $7700.00 | Window Closed / Lapsed |