US3617595A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electric furnace control
Assignee: LAKE ONTARIO STEEL CO Ltd
•
Filing: 1970-09-17
•
Granted: 1971-11-02
•
Expires: 1990-09-17
Abstract
Abstract A method and apparatus for regulating the arc of an electrode in an electric arc melting furnace, in which the voltage drop across the bus bar feeding the electrode is transformed into a comparator signal which is used to regulate the vertical position of the electrode in the furnace to bring the comparator signal to a predetermined value.
Inventors
- 👤 Joseph Aloysius Mulcahy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:52
CPC Classifications
H; H05; H05B; H05B7/00; H05B7/02; H05B7/144; H05B7/148; H05B7/156; Y; Y02; Y02P; Y02P10/00; Y02P10/25
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
117 words
A method of regulating the arc of an electrode in an electric arc melting furnace in which the power is fed to the electrode through a bus bar, comprising the steps of: a. generating a first voltage signal at the input to the bus bar; b. generating a second voltage signal at the connection of the bus bar to the electrode; c. comparing the first and second voltage signals and generating a third signal varying as the difference of the compared signals; and d. employing the third signal to regulate the operation of means controlling the raising and lowering of the electrode to vary the electrode arc whereby the comparator signal is brought to a predetermined value.
Claim 2
Independent Claim
117 words
A method of regulating the arc of an electrode in an electric arc melting furnace in which the power is fed to the electrode through a bus bar, comprising the steps of: a. generating a first voltage signal at the input to the bus bar; b. generating a second voltage signal at the connection of the bus bar to the electrode; c. comparing the first and second voltage signals and generating a third signal varying as the difference of the compared signals; and d. employing the third signal to regulate the operation of means controlling the raising and lowering of the electrode to vary the electrode arc whereby the comparator signal is brought to a predetermined value.
Claim 3
Dependent Claim
17 words
A method as claimed in claim 1 in which the first and second voltage signals are rectified.
Claim 4
Dependent Claim
113 words
Apparatus for regulating the arc of an electrode in an electric arc melting furnace in which power is fed to the electrode through a bus bar, comprising; a. means to generate a first voltage signal at the input to the bus bar; b. means to generate a second voltage signal at the connection of the bus bar to the electrode; c. means to compare the first and second voltage signals and generate a third signal varying as the difference of the compared signals; and d. control means to employ the third signal to raise and lower the electrode to vary the electrode arc whereby the third signal is brought to a predetermined value.
Claim 5
Dependent Claim
113 words
Apparatus for regulating the arc of an electrode in an electric arc melting furnace in which power is fed to the electrode through a bus bar, comprising; a. means to generate a first voltage signal at the input to the bus bar; b. means to generate a second voltage signal at the connection of the bus bar to the electrode; c. means to compare the first and second voltage signals and generate a third signal varying as the difference of the compared signals; and d. control means to employ the third signal to raise and lower the electrode to vary the electrode arc whereby the third signal is brought to a predetermined value.
Claim 6
Dependent Claim
16 words
Apparatus as claimed in claim 3 including means to rectify the first and second voltage signals.
Claim 7
Dependent Claim
32 words
Apparatus as claimed in claim 3 including means for providing a bias signal and means to compare the bias signal and the third signal to produce a signal varying as their sum.
Claim 8
Dependent Claim
28 words
Apparatus as claimed in claim 3 including means for disconnecting the third signal from the control means and connecting to the control means a manually controllable signal source.
Claim 9
Dependent Claim
77 words
Apparatus as claimed in claim 3 in which the control means comprises hydraulic means for raising and lowering the electrode, electric motor means fed from an alternating current power supply and designed and connected to control the hydraulic means, and silicon-controlled rectifier having its anode-cathode circuit connected in series with the power supply of the motor means, and means to delay the firing of the silicon-controlled rectifier in inverse proportion to the magnitude of the third signal.
Claim 10
Dependent Claim
41 words
Apparatus as claimed in claim 7 including means for providing a feedback signal varying as the armature voltage of the bleed motor and means to compare the third signal and the feedback signal to produce a signal varying as their difference.
Claim 11
Dependent Claim
41 words
Apparatus as claimed in claim 7 including means for providing a feedback signal proportional to the armature current of the bleed motor and means to compare the feedback signal and the third signal to produce a signal varying as their difference.
Claim 12
Dependent Claim
61 words
Apparatus as claimed in claim 7 including means for providiNg a bias signal, means for providing a feedback signal varying as the armature voltage of the bleed motor, and means for providing a signal varying as the difference of: the sum of the third signal and the bias signal on the one hand and the feedback signal on the other hand.
Claim 13
Dependent Claim
38 words
Apparatus as claimed in claim 7 in which the electric motor means comprises a direct current motor adapted to bleed the hydraulic means in direct proportion to the magnitude of the third signal whereby the electrode is lowered.
References Cited (Backward Citations)
US3255291A
Cited
US3414657A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |