Patent US5117439A successfully refreshed from Google Patents.
US5117439A
Expired / Lapsed
US
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Method for operating an electrode graphitization furnace
Assignee: Graftech International Holdings Inc
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Filing: 1991-03-29
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Granted: 1992-05-26
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Expires: 2011-03-29
Abstract
Abstract The electric furnace operating cycle time is substantially reduced by directing water into the porous pack of carbonaceous material surrounding the electrodes at a water rate adjusted to maximize vaporization of water into steam within the porous pack while allowing the steam to escape without contacting the electrodes.
Inventors
- 👤 Frank J. Dagata
- 👤 Kenneth G. Politowicz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:13
CPC Classifications
H; H05; H05B; H05B3/00; H05B3/60; C; C04; C04B; C04B35/00; C04B35/515; C04B35/52; H05B7/00; H05B7/02; H05B7/06; H05B7/08; H05B7/085; Y; Y10; Y10T; Y10T428/00; Y10T428/30
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
168 words
A method for operating an electric furnace in the conversion of carbon electrodes to graphite electrodes comprising the steps of: loading ungraphitized carbon electrodes upon a bed of carbonaceous material, into said furnace; surrounding said carbon electrodes with presized granulated particles of carbonaceous material to form a porous pack of thermal insulation; passing electric current through or around said carbon electrodes to elevate the temperature of said electrodes to a temperature above 2800° C. for converting the carbon electrodes into graphitized electrodes; terminating said current flow; directing water into said porous pack of carbonaceous material to form a cool blanket of packing material over said electrodes with the rate of water adjusted to percolate through said porous pack to a controlled depth represented by an area saturated with water and an area of vaporized water with the vaporization of water into steam occurring at a rate such that essentially no water or water vapor comes into contact with the electrodes; and removing the graphitized electrodes from the furnace.
Claim 2
Independent Claim
168 words
A method for operating an electric furnace in the conversion of carbon electrodes to graphite electrodes comprising the steps of: loading ungraphitized carbon electrodes upon a bed of carbonaceous material, into said furnace; surrounding said carbon electrodes with presized granulated particles of carbonaceous material to form a porous pack of thermal insulation; passing electric current through or around said carbon electrodes to elevate the temperature of said electrodes to a temperature above 2800° C. for converting the carbon electrodes into graphitized electrodes; terminating said current flow; directing water into said porous pack of carbonaceous material to form a cool blanket of packing material over said electrodes with the rate of water adjusted to percolate through said porous pack to a controlled depth represented by an area saturated with water and an area of vaporized water with the vaporization of water into steam occurring at a rate such that essentially no water or water vapor comes into contact with the electrodes; and removing the graphitized electrodes from the furnace.
Claim 3
Dependent Claim
30 words
A method as defined in claim 1 wherein said ungraphitized carbon electrodes are loaded into said furnace with the electrodes aligned end to end in an electrical series circuit relationship.
Claim 4
Dependent Claim
39 words
A method as defined in claim 2 wherein said furnace has a common center wall and wherein at least one row of electrodes is aligned on opposite sides of said center wall and connected through a common cross-over member.
Claim 5
Dependent Claim
25 words
A method as defined in claim 4 wherein said rate of water applied to said porous pack is between 4 and 25 gallons per minute.
Claim 6
Dependent Claim
30 words
A method as defined in claim 5 wherein said cooling water is applied to said porous pack through a plurality of uniformly distributed water nozzles suspended above said porous pack.
Claim 7
Dependent Claim
35 words
A method as defined in claim 4 wherein said water is applied to said porous pack through a plurality of uniformly distributed water nozzles extending from a common manifold supported by said common center wall.
Claim 8
Dependent Claim
18 words
A method as defined in claim 5 wherein said water is applied in the form of a spray.
Claim 9
Dependent Claim
18 words
A method as defined in claim 5 wherein said water is applied in the form of water droplets.
Claim 10
Dependent Claim
23 words
A method as defined in claim 1 further comprising applying water to said bed of carbonaceous material after the graphitizing electrodes are removed.
Claim 11
Dependent Claim
23 words
A method as defined in claim 9 wherein said water is applied at a rate of between 4 to 25 gallons per minute.
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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) | 1995-05-26 | 1995-11-25 | 1996-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-26 | 1999-11-25 | 2000-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-26 | 2003-11-25 | 2004-05-26 | $7700.00 | Window Closed / Lapsed |