US3662075A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and system for controlling electric furnaces as a function of power factor
Assignee: JFE Engineering Corp
•
Filing: 1970-10-22
•
Granted: 1972-05-09
•
Expires: 1990-10-22
Abstract
Abstract In an electric furnace control system of the type wherein an electrode driving mechanism is operated by the electrode control signals provided by an automatic current regulator responsive to the current flowing through the electrode, there are provided a program control connected between the automatic current regulator and the electrode driving mechanism for transmitting the electrode control signals to the electrode driving mechanism, and a power factor regulator responsive to the actual power factor of the furnace for controlling the program control.
Inventors
- 👤 Makoto Sakai
- 👤 Shinichi Miyao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 05:17
CPC Classifications
H; H05; H05B; H05B7/00; H05B7/02; H05B7/144; H05B7/148; Y; Y02; Y02P; Y02P10/00; Y02P10/25
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
91 words
A method of controlling an electric furnace of the type wherein the power input to the furnace is controlled in accordance with the current, comprising the steps of: predetermining a power factor limit for the maximum power under various operating conditions; detecting the actual power factor of each electrode; and automatically regulating the position of said electrode in the furnace according to said actual power factor and said predetermined power factor limit, whereby to operate the furnace at a point close to or at, but not exceeding, said power factor limit.
Claim 2
Independent Claim
91 words
A method of controlling an electric furnace of the type wherein the power input to the furnace is controlled in accordance with the current, comprising the steps of: predetermining a power factor limit for the maximum power under various operating conditions; detecting the actual power factor of each electrode; and automatically regulating the position of said electrode in the furnace according to said actual power factor and said predetermined power factor limit, whereby to operate the furnace at a point close to or at, but not exceeding, said power factor limit.
Claim 3
Dependent Claim
101 words
An electric furnace control system comprising: an electrode driving mechanism; an automatic current regulator generating a first current responsive to the current flowing through said electrode; a power factor regulator for detecting the actual power factor of said furnace electrode; and a program control unit connected between said automatic current regulator and said electrode driving mechanism, and responsive to the output of said power factor regulator, for transmitting electrode control signals to said electrode driving mechanism to regulate the position of said electrode in the furnace to cause said actual power factor to at least approach a predetermined power factor limit.
Claim 4
Dependent Claim
101 words
An electric furnace control system comprising: an electrode driving mechanism; an automatic current regulator generating a first current responsive to the current flowing through said electrode; a power factor regulator for detecting the actual power factor of said furnace electrode; and a program control unit connected between said automatic current regulator and said electrode driving mechanism, and responsive to the output of said power factor regulator, for transmitting electrode control signals to said electrode driving mechanism to regulate the position of said electrode in the furnace to cause said actual power factor to at least approach a predetermined power factor limit.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein said furnace is operated close to said power factor limit.
Claim 6
Dependent Claim
29 words
The method of claim 1 wherein the height of the electrode in the furnace is regulated in accordance with said actual power factor and said predetermined power factor limit.
Claim 7
Dependent Claim
21 words
The method of claim 1 wherein said actual power factor is detected by detecting the electrode current and the electrode voltage.
Claim 8
Dependent Claim
63 words
The method of claim 1 wherein said step of regulating the position of said electrode includes operating on a current corresponding to said electrode current as a function of the detected actual power factor and generating a control current to vary the electrode position in order to cause said control current to approach, but not exceed, said current corresponding to said electrode current.
Claim 9
Dependent Claim
55 words
An electric furnace control system according to claim 2 wherein said program control unit causes said actual power factor to be close to but not exceed said predetermined power factor limit. 6 An electric furnace control system according to claim 2 wherein said electrode drive mechanism regulates the height of said electrode in the furnace.
Claim 10
Dependent Claim
23 words
An electric furnace control system according to claim 2 wherein said power factor regulator is responsive to the electrode current and electrode voltage.
Claim 11
Dependent Claim
44 words
An electric furnace control system according to claim 2 wherein said program control system according to claim 2 unit varies the output signal from said current regulator as a function of the output of said power factor regulator to thereby provide said control signals.
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) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |