Burner control method involving the injection of an additional gas and associated combustion system

Abstract

Methods and apparatus for controlling the operation of a burner used for heating liquid glass feeders of a glass furnace. A burner is supplied with a fuel and oxygen. An additional gas is injected so that the sum of the oxygen flow, the fuel flow and the additional gas flow is greater than a minimum cooling flow for the burner.

1 - 16 . (canceled)  
     
     
         17 . A method which may be used for controlling a burner for heating liquid glass feeders of a glass furnace, said method comprising: 
 a) feeding at least one burner with a combustible gas and oxygen; and    b) injecting an additional gas as a complement to said oxygen such that the sum of the flow rates for said combustible gas, said oxygen, and said additional gas is greater than or equal to a minimum flow rate for cooling the burner.    
     
     
         18 . The method of  claim 17 , wherein said additional gas comprises at least one member selected from the group consisting of: 
 a) air;    b) carbon dioxide;    c) argon;    d) helium; and    e) nitrogen.    
     
     
         19 . The method of  claim 17 , further comprising mixing said additional gas and said oxygen prior to introducing said combustible gas.  
     
     
         20 . The method of  claim 17 , wherein said minimum flow rate is set according to the flow rate of said combustible gas.  
     
     
         21 . The method of  claim 17 , wherein the sum of the flow rates for said additional gas and said oxygen is greater than or equal to said minimum flow rate.  
     
     
         22 . The method of  claim 17 , wherein said flow rate for said additional gas is controlled by a pressure regulator located on a line which delivers oxygen to said burner.  
     
     
         23 . The method of  claim 17 , wherein said burner comprises: 
 a) a first duct for the passage of said oxygen;    b) a second duct for the passage of said combustible gas, wherein: 
 1) said second duct is coaxially located substantially inside of said first duct; and  
 2) said second duct's end portion is located back from said first duct's end portion.  
   
     
     
         24 . The method of  claim 17 , wherein said burner comprises: 
 a) a first duct for the passage of said oxygen;    b) a second duct for the passage of said combustible gas, wherein said second duct is coaxially located substantially inside of said first duct;    c) an end-fitting located at said first duct's end portion;    d) a nozzle located at said second duct's end portion; and    e) a combustible gas swirling means, located at said second duct's end portion, to cause said combustible gas to move in a swirling manner.    
     
     
         25 . The method of  claim 24 , wherein: 
 a) said swirling means comprises an object of elongated shape which is centered aerodynamically within said nozzle; and    b) said nozzle has an inside diameter which is greater than the diameter of said object of elongated shape.    
     
     
         26 . The method of  claim 25 , wherein: 
 a) said object of elongated shape comprises at least one helical rod; and    b) said helical rod is located over a portion of said object's length.    
     
     
         27 . The method of  claim 24 , wherein said burner comprises an oxidizer swirling means located on said end-fitting.  
     
     
         28 . An apparatus which may be used as a combustion system, said apparatus comprising: 
 a) an oxyfuel burner;    b) a means for feeding said burner with fuel;    c) a means for feeding said burner with an oxidizer;    d) an oxygen feed means;    e) an additional gas feed means, wherein said oxidizer feed means cooperates with said oxygen feed means and said additional gas feed means;    f) a means for measuring a flow rate, wherein said flow rate comprises at least one member selected form the group consisting of: 
 1) said oxygen's flow rate; and  
 2) said fuel's flow rate; and  
   g) a means for controlling said additional gas's flow rate.    
     
     
         29 . The apparatus of  claim 28 , wherein said means for controlling said additional gas's flow rate is slaved to said means for measuring a flow rate.  
     
     
         30 . The apparatus of  claim 28 , wherein said means for controlling said additional gas's flow rate is a pressure regulator.  
     
     
         31 . The apparatus of  claim 28 , wherein said means for controlling said additional gas's flow rate is a servovalve.  
     
     
         32 . A method which may be used for heating a liquid glass feeder of a glass furnace, said method comprising, heating at least one liquid glass feeder with a combustion system, wherein: 
 a) said liquid gas feeder is connected to a glass furnace; and    b) said combustion system comprises: 
 1) an oxyfuel burner;  
 2) a means for feeding said burner with fuel;  
 3) a means for feeding said burner with an oxidizer;  
 4) an oxygen feed means;  
 5) an additional gas feed means, wherein said oxidizer feed means cooperates with said oxygen feed means and said additional gas feed means;  
 6) a means for measuring a flow rate, wherein said flow rate comprises at least one member selected form the group consisting of: 
 i) said oxygen's flow rate; and  
 ii) said fuel's flow rate; and  
 
 7) a means for controlling said additional gas's flow rate.  
   
     
     
         33 . A method which may be used for controlling a burner for heating liquid glass feeders of a glass furnace, said method comprising: 
 a) feeding at least one burner with a combustible gas and oxygen, wherein said burner comprises: 
 1) a first duct for the passage of said oxygen;  
 2) a second duct for the passage of said combustible gas, wherein said second duct is coaxially located substantially inside of said first duct;  
 3) an end-fitting located at said first duct's end portion;  
 4) a nozzle located at said second duct's end portion; and  
 5) a combustible gas swirling means, located at said second duct's end portion, to cause said combustible gas to move in a swirling manner;  
   b) injecting an additional gas as a complement to said oxygen such that the sum of the flow rates for said combustible gas, said oxygen, and said additional gas is greater than or equal to a minimum flow rate for cooling the burner, wherein said additional gas is mixed with said oxygen prior to introducing said combustible gas; and    c) controlling said flow rate for said additional gas by a pressure regulator located on a line which delivers oxygen to said burner.