# US 7,611,563 B2 · Multifunction injector and relative combustion process for metallurgical treatment in an electric arc furnace > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,611,563 B2 - Document ID: US7611563B2 - Status: Granted - Kind: B2 - Application number: 11/883,662 - Filed: 2006-02-13 - Published: 2008-06-12 - Granted: 2009-11-03 - Earliest claimed: 2005-02-18 - Assignees: Techint Compagnia Tenica Internazionale S.p.A. - Inventors: Francesco Memoli; Mauro Bianchi Ferri; Marcello Pozzi; Enrico Malfa - Web page: https://patentgrep.com/patent/US7611563B2 ## CPC - F23D 14/24: at least one of the fluids being submitted to a swirling motion - C21C 5/5217: {equipped with burners or devices for injecting gas, i.e. oxygen, or pulverulent materials into the furnace} - F23D 14/32: using a mixture of gaseous fuel and pure oxygen or oxygen-enriched air (F23D14/38 takes precedence) - F23D 14/84: Flame spreading or otherwise shaping (F23D14/70 takes precedence) - Y02P 10/20: Recycling - F23D: BURNERS - C21C: PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract A multifunction injector (10, 11, 12) comprising a De Laval nozzle (20) adapted to act as a burner at subsonic or supersonic speed, combined with a plurality of nozzles (31, 32) for fuel and comburant respectively, arranged in two rings, concentric and co-axial to said De Laval nozzle (20) and externally protected by a specifically shaped protection cavity (40). ## Claims ### Claim 1 Multifunction injector (10, 11, 12) having a central axis, said injector comprising a De Laval nozzle (20) adapted to act as a burner at subsonic or supersonic speed, combined with a plurality of fuel nozzles (31) and an external ringa of comburant nozzles (32) respectively, arranged in two rings, concentric and coaxial to said De Laval nozzle (20) and externally protected by a specifically shaped protection cavity (40) wherein the external ring of comburant nozzles (32) has ducts (33) provided on a slope in relation to the central axis wherein said ducts (33) are arranged in a spiral form to cause a swirl rotation of oxidizing gases or fuels and the specifically shaped protection cavity (40) is conically shaped. ### Claim 2 (depends on 1) Multifunction injector (10, 11, 12) according to claim 1, characterised in that said De Laval nozzle (20) has a mouthpiece, said DeLaval nozzle (20) comprising the following in sequence starting from the mouthpiece: a conical converging inlet section (21), having a length L1, inlet (25) with inlet diameter Din and half-angle of incidence (β); a cylindrical throat (22) having a length (L2) and a throat diameter (Dth); a circumferential tapering between the conical inlet section (21) and the following central cylindrical throat (22), having a radius (R1); a conical diverging section (23), having a length (L3), and half-angle of incidence (OC); a circumferential tapering between the throat (22) and the conical diverging outlet section (23), having a radius (R2); a final cylindrical oxygen emission section (24), having a length (L4) and an outlet diameter (Dexit), a circumferential tapering between the conical diverging section (23) and the final cylindrical oxygen emission section (24) having a radius (R3). ### Claim 3 (depends on 2) Multifunction injector (10, 11, 12) according to claim 2 characterised in that said De Laval nozzle (20) is constructed according to the following dimensional relations: the half-angle (β) of the converging conical inlet section (21) is between 7° and 20°; the half angle (α) of the diverging conical outlet section (23) is between 2° and 7°; the tapering radius (R1) between the conical inlet section (21) and the cylindrical throat (22) is between 1 and 10 times the diameter (Dth) of the throat;—the length (L2) of the cylindrical throat (22) is between 0.5 and 5 times the diameter of the throat itself (Dth); the tapering radius (R2) between the cylindrical throat (22) and the diverging conical outlet section (23) is between 1 and 15 times the diameter of the throat (Dth); the tapering radius (R3), between the diverging conical section (23) and the final cylindrical section (24) is between 20 and 80 times the diameter of the throat (Dth)/—the length of the final cylindrical section (24) is between 0 and 3 times the diameter of the throat (Dth). ### Claim 4 (depends on 1) Multifunction injector (10, 11, 12) according to claim 1, characterised in that said fuel injection nozzles (31) are positioned in a complete ring around the De Laval oxygen nozzle (20) and inside the comburant nozzle (32) ring. ### Claim 5 (depends on 4) Multifunction injector (10, 11, 12) according to claim 4, characterised in that said fuel injection nozzles (31) are of a number between 8 and 20, and that their section can be trapezoid, circular or any other geometrical form. ### Claim 6 (depends on 1) Multifunction injector (10, 11, 12) according to claim 1, characterised in that the number of said comburant emission nozzles (32) is preferably between 5 and 20, and that their individual section can be circular, semicircular, or trapezoid, or of any other geometrical form. ### Claim 7 (depends on 1) Multifunction injector (10, 11, 12) according to claim 1, characterised in that said specifically shaped protection cavity (40) presents a first section (43) and a second section (44) in sequence with a conical form preferably between 20° and 30°. ### Claim 8 (depends on 1) Multifunction injector (10, 11, 12) according to claim 1, characterised in that said specifically shaped protection cavity (40) presents a constant conical form (42) of preferably 20°. ### Claim 9 (depends on 1) Combustion process for metallurgical treatment in an electric arc furnace using the multifunction injector according to claim 1, characterised in that it generates an added circumferential and tangential speed component for external comburant and fuel injection, operating the following steps: acting as a burner with a subsonic De Laval nozzle (20) with rapid combustion gas mixing, and aimed at obtaining a wide flame able to heat scrap agglomerates located in front of it apidly and efficiently; acting as a burner with a supersonic De Laval nozzle with a concentrated high pulse flame aimed at cutting the scrap and thus breaking up conglomerate formations in front of the multifunction injector; acting as an oxygen injector at supersonic speed with supersonic area extended as far as 70 times the outlet diameter of the De Laval nozzle, using a shrouding method to confine the flare laterally, and in this condition being able to send an oxygen injection directly into a liquid metal bath.