Method for operating a vacuum melting system, and vacuum melting system operated according to said method

Abstract

A method operates a vacuum melting system for metallurgically treating molten steel. A vacuum melting system is operated according to the method. The acoustic signals generated in a ladle which receives the molten steel are detected by at least one structure-borne noise detector which is directly or indirectly acoustically coupled to the ladle, and the acoustic signals are used to ascertain the height or the thickness of the foamed slag which can be found in the ladle over the molten bath of the molten steel.

1 - 10 . (canceled) 
     
     
         11 . A method for operating a vacuum melting system for metallurgical treatment of a steel melt, the steel melt being treated in a pan inserted in a vacuum vessel, the steel melt including a liquid melt bath and a foamed slag located on top of the liquid melt bath, the method comprising:
 directly and/or indirectly coupling at least one structure-borne sound pick-up to the pan;   picking up, with the at least one structure-borne sound pick-up, acoustic signals generated within the pan; and   determining at least one of a total height of the foamed slag and the liquid melt bath within the pan and a depth of the foamed slag above the liquid melt bath, based on the acoustic signals that are picked up by the at least one structure-borne sound pick-up.   
     
     
         12 . The method as claimed in  claim 11 , further comprising:
 determining at least one of a temporal differential quotient of the total height and a temporal differential quotient of the depth based on the acoustic signals that are picked up by the at least one structure-borne sound pick-up.   
     
     
         13 . The method as claimed in  claim 12 , further comprising:
 controlling a feeding of a process gas into the pan based on at least one of the total height and the depth and/or at least one of the temporal differential quotient of the total height and the temporal differential quotient of the depth.   
     
     
         14 . The method as claimed in  claim 11 , further comprising:
 detecting a leakage in the vacuum melting system based on the acoustic signals that are picked up by the at least one structure-borne sound pick-up.   
     
     
         15 . A vacuum melting system for metallurgical treatment of a steel melt, the system comprising:
 a vacuum vessel;   a pan configured to be inserted inside the vacuum vessel and configured to hold the steel melt, the steel melt including a liquid melt bath and a foamed slag located on top of the liquid melt bath;   at least one structure-borne sound pick-up indirectly or directly coupled to the pan and configured to pick up acoustic signals generated within the pan; and   a control processor configured to determine at least one of a total height of the foamed slag and the liquid melt bath within the pan and a depth of the foamed slag above the liquid melt bath based on the acoustic signals picked up by the at least one structure-borne sound pick-up and/or at least one of a temporal differential quotient of the total height and a temporal differential quotient of the depth, based on the acoustic signals picked up by the at least one structure-borne sound pick-up.   
     
     
         16 . The vacuum melting system as claimed in  claim 15 , wherein the at least one structure-borne sound pick-up is fixed to the pan. 
     
     
         17 . The vacuum melting system as claimed in  claim 16 , wherein the at least one structure-borne sound pick-up is fixed to an upper area of the pan. 
     
     
         18 . The vacuum melting system as claimed in  claim 15 , wherein the vacuum vessel includes a cover configured to close the vacuum vessel and the at least one structure-borne sound pick-up is permanently installed on the vacuum vessel and/or the cover. 
     
     
         19 . The vacuum melting system as claimed in  claim 15 , wherein the control processor is further configured to regulate the total height or the depth of the foamed slag by controlling a feeding of a process gas into the pan as a function of at least one of the total height and the depth of the foamed slag and/or at least one of the temporal differential quotient of the total height and the temporal differential quotient of the depth of the foamed slag. 
     
     
         20 . The vacuum melting system as claimed in  claim 15 , wherein the control processor is further configured to detect a leakage in the vacuum melting system based on the acoustic signals picked up by the at least one structure-borne sound pick-up. 
     
     
         21 . The method as claimed in  claim 11 , further comprising fixing the at least one structure-borne sound pick-up to an upper area of the pan. 
     
     
         22 . The method as claimed in  claim 11 , further comprising permanently fixing the at least one structure-borne sound pick-up to the vacuum vessel and/or a cover of the vacuum vessel. 
     
     
         23 . The method as claimed in  claim 11 , further comprising fixing the at least one structure-borne sound pick-up to the pan after the pan is inserted into the vacuum vessel. 
     
     
         24 . The method as claimed in  claim 11 , further comprising determining the total height or the depth of the foamed slag by comparing the acoustic signals picked up by the at least one structure-borne sound pick-up with previously learned acoustic signals in a self-learning physical model. 
     
     
         25 . The method as claimed in  claim 12 , wherein the temporal differential quotient of the total height is represented as a change in the total height over time and the temporal differential quotient of the depth is represented as a change in the depth over time. 
     
     
         26 . The vacuum melting system as claimed in  claim 15 , wherein the vacuum vessel includes a cover configured to close the vacuum vessel. 
     
     
         27 . The vacuum melting system as claimed in  claim 26 , wherein the at least one structure-borne sound pick-up includes at least two structure-borne sound pick-ups fixed to the pan, at least one structure-borne sound pick-up fixed to the vacuum vessel, and at least one structure-borne sound pick-up fixed to the cover of the vacuum vessel. 
     
     
         28 . The vacuum melting system as claimed in  claim 15 , wherein the control processor determines the total height or the depth of the foamed slag and/or the temporal differential quotient of the total height or the temporal differential quotient of the depth of the foamed slag by comparing the acoustic signals picked up by the at least one structure-borne sound pick-up with previously learned acoustic signals in a self-learning physical model. 
     
     
         29 . The vacuum melting system as claimed in  claim 15 , wherein the temporal differential quotient of the total height is represented as a change in the total height over time and the temporal differential quotient of the depth is represented as a change in the depth over time.