Method and Device for Controlling Vibrations of a Metallurgical Vessel

Abstract

In a method and a device for controlling vibrations of a metallurgical vessel that occur while gas is being injected into liquid molten metal located in the metallurgical vessel, a certain total amount of gas per unit of time is injected into the liquid molten metal, and the total amount of gas being is injected into the liquid molten metal through a number of individual nozzles in the metallurgical vessel, measured values correlating with the vibrations of the metallurgical vessel occurring are being measured during the injection, wherein while keeping the total amount of gas injected per unit of time largely constant, the amount of gas injected from individual nozzles per unit of time is changed in dependence on the measured values that are measured and correlate with the vibrations of the metallurgical vessel occurring.

1 . A method for controlling vibrations of a metallurgical vessel occurring during the injection of gas into the metallurgical vessel filled with liquid molten metal, the method comprising:
 injecting a certain total amount of gas per unit of time into the liquid molten metal,   wherein the total amount of gas is injected into the liquid molten metal through a number of individual nozzles in the metallurgical vessel,   and measuring measured values correlating with the vibrations of the metallurgical vessel occurring during the injection,   wherein   while keeping the total amount of gas injected per unit of time largely constant, the amount of gas injected from individual nozzles per unit of time is changed in dependence on the measured values that are measured and correlate with the vibrations of the metallurgical vessel occurring.   
     
     
         2 . The method according to  claim 1 , wherein, at least for one of the individual nozzles, the amount of gas injected from them per unit of time is changed, at least for a time, in dependence on measured values correlating with the vibrations of the metallurgical vessel occurring. 
     
     
         3 . The method according to  claim 2 , wherein the changing of the intensity of at least one measured value correlating with the vibrations of the metallurgical vessel occurring that is brought about by changing the amount of gas injected from an individual nozzle per unit of time is traced, and the changing of the amount of gas injected from an individual nozzle per unit of time is carried out until the at least one measured value correlating with the vibrations of the metallurgical vessel occurring reaches a prescribed value or until the gas flow from the nozzle reaches a prescribed maximum or minimum. 
     
     
         4 . The method according to  claim 1 , wherein the measured values correlating with the vibrations of the metallurgical vessel occurring are filtered and digitally processed before they are used for changing the amount of gas injected from the individual nozzles per unit of time. 
     
     
         5 . The method according to  claim 1 , wherein, when measuring the measured values correlating with the vibrations of the metallurgical vessel occurring, at least one of frequencies and intensities of vibrations are determined. 
     
     
         6 . The method according to  claim 1 , wherein the measured values correlating with the vibrations of the metallurgical vessel occurring correlate with vibrations of the metallurgical vessel that have frequencies between 0.1 Hertz and 100 Hertz or between 0.2 Hertz and 20 Hertz. 
     
     
         7 . The method according to  claim 1 , wherein the measured values, correlating with the vibrations of the metallurgical vessel occurring, in dependence on which the amount of gas introduced from individual nozzles per unit of time is changed correlate with vibrations of the metallurgical vessel of frequencies that lie between 0.2 Hertz and 20 Hertz. 
     
     
         8 . A device for controlling vibrations of a metallurgical vessel occurring during the injection of gas into the metallurgical vessel filled with liquid molten metal and provided with a number of individual nozzles for the injection of gas, the individual nozzles being respectively connected to a gas feed line of their own, comprising:
 at least one sensor for measured values correlating with the vibrations of the metallurgical vessel occurring,   a processing unit for processing the measured values measured by the sensor, and   in at least two gas feed lines there is at least one device for changing the gas flow through the gas feed line,   and each device for changing the gas flow is connected to the processing unit.   
     
     
         9 . The device according to  claim 8 , wherein the device for changing the gas flow through the gas feed line allows a continuous changing of the gas flow. 
     
     
         10 . The device according to  claim 8 , wherein the device for changing the gas flow through the gas feed line is a device for changing the gas flow in stages. 
     
     
         11 . The device according to  claim 8 , wherein the sensor for measured values correlating with the vibrations of the metallurgical vessel occurring is a vibration sensor. 
     
     
         12 . The device according to  claim 11 , wherein the vibration sensor is a torque measurement, a strain gage, a position pickup, a velocity pickup or an acceleration pickup. 
     
     
         13 . The method according to  claim 1 , wherein, for two or more of the individual nozzles, the amount of gas injected from them per unit of time is changed, at least for a time, in dependence on measured values correlating with the vibrations of the metallurgical vessel occurring. 
     
     
         14 . A system for controlling vibrations of a metallurgical vessel occurring during the injection of gas into the metallurgical vessel filled with liquid molten metal, comprising:
 a metallurgical vessel,   a plurality of individual nozzles for injecting a certain total amount of gas per unit of time into the liquid molten metal,   wherein the system is configured to measure values correlating with the vibrations of the metallurgical vessel occurring during the injection, and   a control unit which, while keeping the total amount of gas injected per unit of time largely constant, is operable to change the amount of gas injected from individual nozzles per unit of time in dependence on the measured values that are measured and correlate with the vibrations of the metallurgical vessel occurring.   
     
     
         15 . The system according to  claim 14 , wherein, at least for one of the individual nozzles, the amount of gas injected from them per unit of time is changed, at least for a time, in dependence on measured values correlating with the vibrations of the metallurgical vessel occurring. 
     
     
         16 . The system according to  claim 15 , wherein the changing of the intensity of at least one measured value correlating with the vibrations of the metallurgical vessel occurring that is brought about by changing the amount of gas injected from an individual nozzle per unit of time is traced, and the changing of the amount of gas injected from an individual nozzle per unit of time is carried out until the at least one measured value correlating with the vibrations of the metallurgical vessel occurring reaches a prescribed value or until the gas flow from the nozzle reaches a prescribed maximum or minimum. 
     
     
         17 . The system according to  claim 14 , wherein the measured values correlating with the vibrations of the metallurgical vessel occurring are filtered and digitally processed before they are used for changing the amount of gas injected from the individual nozzles per unit of time. 
     
     
         18 . The system according to  claim 14 , wherein, when measuring the measured values correlating with the vibrations of the metallurgical vessel occurring, at least one of frequencies and intensities of vibrations are determined. 
     
     
         19 . The system according to  claim 14 , wherein the measured values correlating with the vibrations of the metallurgical vessel occurring correlate with vibrations of the metallurgical vessel that have frequencies between 0.1 Hertz and 100 Hertz. 
     
     
         20 . The system according to  claim 14 , wherein the measured values, correlating with the vibrations of the metallurgical vessel occurring, in dependence on which the amount of gas introduced from individual nozzles per unit of time is changed correlate with vibrations of the metallurgical vessel of frequencies that lie between 0.2 Hertz and 20 Hertz.