Glass melting furnace

Abstract

The present invention relates to a glass melting furnace, comprising a channel-shaped melting tank, the batch material being charged at an upstream end, the molten glass being recovered at the downstream end, said furnace being heated by means of burners, in which 80% of the combustion energy is produced by oxycombustion, oxygen being supplied continuously from a production plant located nearby or via a gas pipe from remotely located plants, characterized in that the furnace is fitted with oxygen storage means such that, should continuous supply cease, the furnace can operate at least in a temperature-maintaining mode for a maximum time of eight hours.

1 . A glass melting furnace, comprising:
 a channel-shaped melting tank, wherein the introduction of batch materials is conducted at an upstream end, and molten glass is recovered at the downstream end;   at least one burner which heats said furnace, in which, with the at least one burner, at least 80% of the combustion energy is produced by oxy-combustion, wherein oxygen is supplied continuously from a production plant located nearby or via a gas pipe from a remotely located plant; and   an oxygen storage unit, which, should continuous supply cease, assures operation of the furnace at least in a temperature maintaining mode for a minimum period of eight hours.   
     
     
         2 . The melting furnace according to  claim 1 , wherein maintenance of the temperature is assured by adding at least one additional burner that operate by air combustion, and
 wherein a proportion of energy of the at least one additional burner does not represent more than a third of total energy in the temperature maintaining mode.   
     
     
         3 . The furnace according to  claim 2 , comprising
 a traditional melting zone,   a traditional refining zone, and   a traditional conditioning zone, wherein since the traditional conditioning zone does not have a significant supply of energy in ordinary operation, the at least one additional burner operating by air combustion is located in the conditioning zone.   
     
     
         4 . The furnace according to  claim 2 , wherein the air for the air combustion is preheated in heat exchangers. 
     
     
         5 . The furnace according to  claim 4 , comprising:
 a fuel supply comprising either liquid fuel oil or gas; and   at least one heat exchanger which preheats the gas,   wherein the at least one exchanger optionally serves to heat the air during the temperature maintaining mode, and a fuel is liquid fuel oil.   
     
     
         6 . The furnace according to  claim 1 , wherein power delivered by the at least one burner in the temperature maintaining mode is at most equal to a third of power in ordinary operation. 
     
     
         7 . The furnace according to  claim 6 , wherein, in the temperature maintaining mode, only some of the burners for oxy-combustion are kept in operation. 
     
     
         8 . The furnace according to  claim 7 , wherein the burners kept operative are located so that fumes sweep over practically an entire surface of a bath before being evacuated. 
     
     
         9 . The furnace according to  claim 1 , wherein in an ordinary operating mode and in the temperature maintaining mode, at least 65% of fumes are evacuated upstream of the furnace in the vicinity of a location of charging of batch materials. 
     
     
         10 . A process for maintaining a temperature of the furnace according to  claim 1 , the process comprising keeping the burners active such that crown temperatures in melting and refining zones are not less than 1100° C. and in a conditioning zone are not less than 1050° C. 
     
     
         11 . The process according to  claim 10 , wherein elements in contact with molten material that are normally cooled, are either removed from a bath (blenders) or their cooling is interrupted (dams). 
     
     
         12 . The process according to  claim 10 , wherein when the furnace comprises bubblers, operation thereof is maintained strictly at a minimum so that the bubblers are not blocked by setting of the glass. 
     
     
         13 . The furnace according to  claim 1 , wherein the oxygen storage unit assures operation of the furnace at least in the temperature maintaining mode for a minimum period of at least 20 hours. 
     
     
         14 . The furnace according to  claim 1 , wherein the oxygen storage unit assures operation of the furnace at least in the temperature maintaining mode for a minimum period of at least 30 hours. 
     
     
         15 . The furnace according to  claim 6 , wherein, in the temperature maintaining mode, at most half of the burners for oxy-combustion are kept in operation. 
     
     
         16 . The furnace according to  claim 3 , wherein the air for the air combustion is preheated in heat exchangers. 
     
     
         17 . The furnace according to  claim 16 , comprising:
 a fuel supply comprising either liquid fuel oil or gas; and   at least one heat exchanger which preheats the gas,   wherein the at least one exchanger optionally serves to heat the air during the temperature maintaining mode, and a fuel is liquid fuel oil.   
     
     
         18 . The furnace according to  claim 2 , wherein power delivered by the at least one burner in the temperature maintaining mode is at most equal to a third of power in ordinary operation. 
     
     
         19 . The furnace according to  claim 3 , wherein power delivered by the at least one burner in the temperature maintaining mode is at most equal to a third of power in ordinary operation. 
     
     
         20 . The furnace according to  claim 2 , wherein power delivered by the at least one burner in the temperature maintaining mode is at most equal to a third of power in ordinary operation.