# US 9,439,247 B2 · Electrode consumption monitoring system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,439,247 B2 - Document ID: US9439247B2 - Status: Granted - Kind: B2 - Application number: 13/670,981 - Filed: 2012-11-07 - Published: 2013-05-16 - Granted: 2016-09-06 - Earliest claimed: 2011-11-07 - Assignees: GrafTech International Holdings Inc. - Applicants: GrafTech International Holdings Inc. - Inventors: Wyllys King Ingersoll, III - Web page: https://patentgrep.com/patent/US9439247B2 ## CPC - H05B 7/20: Direct heating by arc discharge, i.e. where at least one end of the arc directly acts on the material to be heated, including additional resistance heating by arc current flowing through the material to be heated - F27B 3/28: Arrangement of controlling, monitoring, alarm or the like devices - F27D 19/00: Arrangements of controlling devices - F27D 21/00: Arrangement of monitoring devices; Arrangement of safety devices - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - F27B: FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS - F27D: DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE ## Abstract A method and system automatically determines when an electrode add event occurs in an electric arc furnace having a plurality of electrode columns, each carried by an electrode positioning system. Data is received correlating to the harmonic distortion of the electrical current output to the plurality of electrode columns. Data is also received correlating to control pressures in the electrode positioning systems. Steady state control pressure data is captured when the harmonic distortion data indicates a steady state condition. An electrode add event is thereafter determined when a pressure spike is identified in the steady state control pressure data. ## Claims ### Claim 1 A method for determining when an electrode add event occurs in an electric arc furnace having a plurality of electrode columns, each carried by an electrode positioning system, the method comprising: receiving data correlating to a harmonic distortion of an electrical current output to the plurality of electrode columns; receiving data correlating to control pressures in the electrode positioning system; identifying steady state control pressure data when said harmonic distortion data indicates a steady state condition; and determining the electrode add event when a pressure spike is identified in said steady state control pressure data. ### Claim 2 (depends on 1) The method according to claim 1 wherein said pressure spike is identified when a pressure increase of at least 5% occurs. ### Claim 3 (depends on 1) The method according to claim 1 wherein said pressure spike is identified when a pressure increase of at least 100 psi occurs. ### Claim 4 (depends on 1) The method according to claim 1 wherein the steady state condition is determined when the harmonic distortion of said electrical current flowing through each said electrode column is less than about 10%. ### Claim 5 (depends on 1) The method according to claim 1 wherein the steady state condition is determined when the harmonic distortion of said electrical current flowing through each said electrode column is less than about 5%. ### Claim 6 (depends on 1) The method according to claim 1 wherein the steady state condition is determined when the average harmonic distortion of said electrical current flowing through all said electrode columns is less than about 10%. ### Claim 7 (depends on 1) The method according to claim 1 wherein the steady state condition is determined when the average harmonic distortion of said electrical current flowing through all said electrode columns is less than about 5%. ### Claim 8 (depends on 1) The method according to claim 1 further comprising displaying the steady state control pressure data in graphical form via a website. ### Claim 9 A system for monitoring an electric arc furnace having a plurality of electrode columns, each electrode column having an electrical current output therethrough and being vertically movable by an electrode positioning system, the system comprising: a computing device having therein program code embodied in a non-transitory computer readable medium usable by said computing device, the program code comprising: code configured to receive or request data correlating to a harmonic distortion of the electrical current output to the plurality of electrode columns; code configured to receive or request data correlating to control pressures in the electrode positioning system; code configured to identify steady state control pressure data when said harmonic distortion data indicates a steady state condition; and code configured to determine an electrode add event when a pressure spike is identified in said steady state control pressure data. ### Claim 10 (depends on 9) The system according to claim 9 wherein said pressure spike is identified when a pressure increase of at least 5% occurs. ### Claim 11 (depends on 9) The system according to claim 9 wherein said pressure spike is identified when a pressure increase of at least 50 psi occurs. ### Claim 12 (depends on 9) The system according to claim 9 wherein the steady state condition is determined when the harmonic distortion of said electrical current flowing through each said electrode column is less than about 10%. ### Claim 13 (depends on 9) The system according to claim 9 wherein the steady state condition is determined when the harmonic distortion of said electrical current flowing through each said electrode column is less than about 5%. ### Claim 14 (depends on 9) The system according to claim 9 wherein the steady state condition is determined when the average harmonic distortion of said electrical current flowing through all said electrode columns is less than about 10%. ### Claim 15 (depends on 9) The system according to claim 9 wherein the steady state condition is determined when the average harmonic distortion of said electrical current flowing through all said electrode columns is less than about 5%. ### Claim 16 (depends on 9) The system according to claim 9 further comprising code configured to display the steady state control pressure data in graphical form. ### Claim 17 (depends on 9) The system according to claim 9 further comprising code configured to display electrode add events in graphical form.