Apparatus for injecting gas into a vessel

Abstract

A lance for injecting gas into a furnace vessel. The lance imparts a spiral or swirling flow to gas discharged by the lance. The lance includes a plurality of internally water-cooled flow vanes in fluid communication with a fluid-cooled structure that is discrete from the fluid-cooled outer wall of the lance. The result is a lance that effectively discharges gas with a desired swirling motion, that is comparatively simple in design and construction, and whose flow vanes are capable of withstanding the extreme thermal stresses encountered in a metallurgical or other high temperature furnace vessel.

1 . A gas flow guide assembly for use in a lance for injecting gas into a vessel, the lance having a water-cooled enclosed duct in fluid communication with a first water supply, a water-cooled central structure disposed within the duct and in fluid communication with a second water supply separate from the first water supply, and a gas flow passageway between the duct and central structure in communication with a supply of gas for injecting the gas into a vessel, said gas flow guide assembly comprising:
 an enclosed end;   pipe sections adapted for connection to the central structure and connected to said enclosed end, said pipe sections defining a water supply passage and a water return passage for circulating water from an inlet of the second water supply to an outlet of the second water supply;   helical gas flow guide vane means for imparting a swirling motion to gas discharged by the gas flow passageway; and   at least one coolant passageway in communication with said water supply passage for internally cooling said gas flow guide vane means with water supplied by the second coolant supply.   
   
   
       2 . The gas flow guide assembly of  claim 1  wherein said at least one coolant passageway comprises a plurality of coolant passageways. 
   
   
       3 . The gas flow guide assembly of  claim 2  wherein said plurality of coolant passageways are arranged in an axially and radially nested array. 
   
   
       4 . The gas flow guide assembly of  claim 1  wherein said at least one coolant passageway includes an inlet and an outlet in communication with said water supply passage. 
   
   
       5 . The gas flow guide assembly of  claim 4  further comprising water restriction means disposed in said water supply passage between said inlet and said outlet of said at least one coolant passageway for creating back pressure in said water supply passage for forcing water into said at least said inlet of said at least one coolant passageway. 
   
   
       6 . The gas flow guide assembly of  claim 5  wherein said water restriction means includes at least one aperture for permitting water not directed into said at least said inlet of said at least one coolant passageway to pass through said water restriction means. 
   
   
       7 . A lance for injecting gas into a vessel, said lance comprising:
 a water-cooled enclosed duct in fluid communication with a first water supply;   a water-cooled central structure disposed within said duct and in fluid communication with a second water supply separate from said first water supply;   a gas flow passageway between the duct and central structure in communication with a supply of gas for injecting the gas into a vessel; and   a gas flow guide assembly comprising:
 an enclosed end; 
 pipe sections connected to said central structure and said enclosed end, said pipe sections defining a water supply passage and a water return passage for circulating water from an inlet of said second water supply to an outlet of said second water supply; 
 helical gas flow guide vane means for imparting a swirling motion to gas discharged by the gas flow passageway; and 
 at least one coolant passageway in communication with said water supply passage for internally cooling said gas flow guide vane means with water supplied by the second coolant supply. 
   
   
   
       8 . The lance of  claim 7  wherein said at least one coolant passageway comprises a plurality of coolant passageways. 
   
   
       9 . The lance of  claim 8  wherein said plurality of coolant passageways are arranged in an axially and radially nested array. 
   
   
       10 . The lance of  claim 7  wherein said at least one coolant passageway includes an inlet and an outlet in communication with said water supply passage. 
   
   
       11 . The lance of  claim 10  further comprising water restriction means disposed in said water supply passage between said inlet and said outlet of said at least one coolant passageway for creating back pressure in said water supply passage for forcing water into said at least said inlet of said at least one coolant passageway. 
   
   
       12 . The lance of  claim 11  wherein said water restriction means includes at least one aperture for permitting water not directed into said at least said inlet of said at least one coolant passageway to pass through said water restriction means. 
   
   
       13 . A lance for injecting gas into a vessel, the lance including gas flow guide vane means for imparting a swirling motion to gas discharged by the lance, said gas flow guide means comprising at least one helically-shaped metal conduit embedded in cast copper and operable to convey coolant through said gas flow guide means.