Cooling exhaust gases from smelting furnace

Abstract

In combination with a furnace having a top from which very hot gases are exhausted, a cooling system has an outwardly open collar fixed to the top of the furnace and open inward into the furnace, a tubular exhaust stack adjacent the furnace, a connecting duct extending from the stack and fitted concentrically to the collar, a network of heat-exchange tubes lining the top of the furnace. The collar, and the connecting duct, and means for circulating through all of the tubes a coolant at generally the same temperature.

1 . In combination with a furnace having a top from which very hot gases are exhausted, a cooling system comprising: 
 an outwardly open collar fixed to the top of the furnace and open inward into the furnace;    a tubular exhaust stack adjacent the furnace;    a connecting duct extending from the stack and fitted concentrically to the collar;    a network of heat-exchange tubes lining the top of the furnace, the collar, and the connecting duct; and    means for circulating through all of the tubes a coolant at generally the same temperature.    
   
   
       2 . The exhaust-gas cooling system defined in  claim 1  wherein coolant is at a temperature above 150° C.  
   
   
       3 . The exhaust-gas cooling system defined in  claim 2  wherein the coolant is above 200° C.  
   
   
       4 . The exhaust-gas cooling system defined in  claim 1  wherein the coolant is boiling water.  
   
   
       5 . The exhaust-gas cooling system defined in  claim 1  wherein the network of tubes comprises a multiplicity of tube sections that are individually controllable.  
   
   
       6 . The exhaust-gas cooling system defined in  claim 1  wherein the furnace top has two of the collars extending at an angle of at most 100° to each other.  
   
   
       7 . The exhaust-gas cooling system defined in  claim 6  wherein the two collars extend at an angle of at most 85° to each other.  
   
   
       8 . The exhaust-gas cooling system defined in  claim 6  wherein the tubes lining one of the collars extend continuously into the furnace top and line the furnace top between the collars and then extend into the other of the collars.  
   
   
       9 . The exhaust-gas cooling system defined in  claim 1  wherein the tubes lining the connecting duct project into the collar and overlap the tubes lining the collar.