Device for electrically grounding a float glass production apparatus

Abstract

A float glass apparatus typically includes a float tank for a metal bath, the metal bath, a glass melt producing unit, which includes a melting tank for making a glass melt and a refining, tank for degassing the glass melt, and conducting devices for conducting the glass melt from the glass melt producing unit to the metal bath of the float tank and auxiliary devices as needed. In order to minimize bubble defects and extend service life of Pt units by a suitable electrical device the float tank with the metal bath is connected electrically with ground and at least one auxiliary electrode is connected with ground and put in electrical contact with the glass melt in the melting tank.

1 . A device for electrical grounding of a float glass apparatus, said float glass apparatus comprising a float tank for a metal bath, the metal bath, a glass melt producing unit, said glass melt producing unit including a melting tank for making a glass melt and a refining tank for degassing the glass melt, conducting devices for conducting the glass melt from the glass melt producing unit to the metal bath of the float tank and auxiliary devices as needed; 
 wherein the float tank with the metal bath is connected electrically with ground and at least one auxiliary electrode connected with ground is put in electrical contact with the glass melt in the glass melt producing unit.    
     
     
         2 . The device as defined in  claim 1 , wherein the at least one auxiliary electrode in electrical contact with the glass melt is put in the refining tank of the glass melt producing unit.  
     
     
         3 . The device as defined in  claim 2 , wherein the melting tank has a feed apparatus, a heating burner and an overflow and at least one ground device is fixed to the feed apparatus, the heated burner or the overflow.  
     
     
         4 . The device as defined in  claim 1 , further comprising an auxiliary electro-heating unit with heating electrodes and wherein said at least one auxiliary electrode comprises one of said heating electrodes.  
     
     
         5 . The device as defined in  claim 1 , further comprising an auxiliary electro-heating unit with heating unit electrodes and a heating transformer with a secondary winding, and wherein said heating electrodes are at a voltage proportional to a voltage in the secondary winding of the heating transformer, and said at least one auxiliary electrode comprises a number of said heating electrodes.  
     
     
         6 . The device as defined in  claim 5 , wherein said at least one auxiliary electrode comprises all of said heating electrodes present in said auxiliary electro-heating unit.  
     
     
         7 . The device as defined in  claim 1 , further comprising a controllable ohmic resistor and wherein said controllable ohmic resistor is connected between ground and said at least one auxiliary electrode.  
     
     
         8 . The device as defined in  claim 7 , further comprising an impedance connected in series with the ohmic resistor and between ground and said at least one auxiliary electrode.  
     
     
         9 . The device as defined in  claim 8 , further comprising a rectifier connected in series with the impedance and the ohmic resistor and between ground and the at least one auxiliary electrode.  
     
     
         10 . The device as defined in  claim 1 , wherein said at least one auxiliary electrode, which is put in electrical contact with the glass melt and connected with ground, comprises molybdenum or an alloy of said molybdenum.  
     
     
         11 . The device as defined in  claim 1 , wherein said at least one auxiliary electrode, which is put in electrical contact with the glass melt and connected with ground, comprises tungsten or an alloy of said tungsten.  
     
     
         12 . The device as defined in  claim 1 , wherein the float tank comprises a metallic basin, said metallic basin contains said metal bath and said metallic basin is directly connected with ground.  
     
     
         13 . The device as defined in  claim 12 , wherein said metal bath is a tin bath.  
     
     
         14 . The device as defined in  claim 1 , further comprising a measurement arrangement for direct measurement of an electric current, which flows between an outlet of the glass tank and an inlet of the float tank.  
     
     
         15 . The device as defined in  claim 14 , wherein the measurement arrangement has a current regulator for minimizing the electric current flowing between the outlet of the glass melt producing unit and the inlet of the float tank.  
     
     
         16 . The device as defined in  claim 1 , further comprising a measurement arrangement for indirect measurement of an electric current, which flows between an outlet of the glass melt producing unit and an inlet of the float tank.  
     
     
         17 . The device as defined in  claim 16 , wherein the measurement arrangement has a current regulator for minimizing the electric current flowing between the outlet of the glass tank and the inlet of the float tank.