Abstract: Metallurgical reactor for the production of cast iron, consisting of a metal casing internally lined, at least partially, with refractory material and provided, in the region of the top closure, with a duct through which high-temperature ferrous material is introduced, said reactor being equipped with a first series of lances for injecting the comburent gas, which are suitably directed and arranged on at least a first bottom level situated in the vicinity of the crucible for collecting the cast iron and through which, in association with a comburent gas, coal of suitable grain size is blown by means of a suitable carrier gas. Said duct has suitable cooling means and is provided, in the bottom terminal part, with nozzles for blowing in compressed gas.

Abstract: An injection lance for injecting a homogeneous mixture of steam/ammonia gas into a furnace having a flue gas (combustion) stream moving therethrough to reduce nitrogen oxides therein. The lance includes an outer and an inner tube. The outer end of the inner tube is in communication with the outer tube while the outer end of the outer tube is in communication with a source of homogeneous steam/ammonia. The outer end of the inner tube sealably embraces the exterior surface of the lance feed tube so that the homogeneous steam/ammonia mixture being introduced into the outer tube passes towards the inner end of the lance between the annulus formed by the concentric outer and inner tubes. The homogeneous steam/ammonia mixture is passed into the annular space in the inner tube and then is discharged from the lance through discharge flow control nozzles or ports which extend from the interior of the inner tube to the exterior of the outer tube.

Abstract: A method is for feeding a gas into a metallurgical vessel having a condensable and/or evaporable component entrained by the gas. The gas is fed to the metallurgical vessel via one or more gas supply means. According to the method, if there are a number of the gas supply means, in a first section, the gas velocity is continuously increased, in a turbulence zone, the gas is intimately mixed with the condensable and/or evaporable component, in an exit section, the gas velocity is kept substantially constant, and the gas which has been intimately mixed with the entrained component is blown into the metallurgical vessel. A gas supply device for carrying out the method is also disclosed. The method and apparatus according t the invention make it possible to prevent or reduce nozzle damage.

Abstract: A method for blowing oxygen in a converter uses a top-blown lance having a Laval nozzle installed on its tip. The Laval nozzle has a back pressure of the nozzle Po(kPa) satisfying a formula, Po=FhS/(0.00465·Dt2), with respect to a oxygen-flow-rate FhS(Nm3/hr) per hole of the Laval nozzle determined from the oxygen-flow-rate FS(Nm3/hr) in a high carbon region in a peak of decarburization and a throat diameter Dt(mm). An exit diameter De of the Laval nozzle satisfies the following formula with respect to the back pressure of the nozzle Po(kPa), an ambient pressure Pe(kPa), and the throat diameter Dt(mm): De2≦0.23×Dt2/{(Pe/Po)5/7×[1−(Pe/Po)2/7]1/2}.

Abstract: A gas injection lance and an apparatus employing the lance for producing ferrous metal are provided. The lance has an elongated flow duct made of inner and outer concentric carbon steel tubes, a cooling water supply and return, and exterior surface which is designed to hold a frozen layer of slag on the duct, a gas inlet at a rear end of the duct, a tip joining the concentric tubes at the forward end of the duct, a non-metallic or refractory lining for the duct, and swirl-imparting member or members located in the duct for imparting swirl in the gas flow through the forward end of the duct.

Abstract: A coherent jet lance and operating method wherein the need for a lance extension is eliminated using two rings of ports to deliver respectively fuel and oxidant flame envelope gases around the primary gas jets to maintain the gas jets coherent wherein the ports of the two rings are aligned on the lance face.

Abstract: A coherent jet lance and operating method employing two sets of ports for delivering fuel and oxidant respectively for formation of a flame envelope around one or more gas jets wherein the ports of at least one set and preferably of each set are angled outwardly on the lance face with respect to the lance axis.

Abstract: An assembly wherein inexpensive and essentially maintenance-free disposable sensors may be used in conjunction with a metal making lance. The assembly contemplates the use of disposable sensors that are accommodated by a sensor feed tube disposed interiorly or exteriorly of a conventional metal making lance. The sensors may be selected to detect one or more characteristics of the metal being treated and/or operating conditions of a metal treatment vessel.

Abstract: A modular metalmaking lance having a pre-fabricated “plug-in” lower sections. The plug-in section is preferably of sufficient length to ensure that the joint between a plug-in section and an upper lance section is not in the area of the lance that typically is damaged in refining service. At the same time, the plug-in section is preferably short enough to be transported from an off-site assembly/repair shop to the refining shop via standard-length cargo trucks or truck-trailer rigs used throughout the world.

Abstract: A metallurgical lance for introducing gas from above into a volume of metal in a vessel includes a head having at least one ejector formed therein. The ejector includes a Laval nozzle surrounded by a shrouding gas passage. Both the Laval nozzle and the shrouding gas passage communicate at their proximal ends with a common gas supply chamber. The shrouding gas passage communicates with the chamber via a first annular orifice member which determines the percentage split of the gas flow through the chamber between the Laval nozzle and the shrouding gas passage.

Abstract: A continuous hot rod (10, 30) for removing portions of a target material (20, 40), comprises: an elongated lance formed of a fuel material (15, 35); a reel for providing a continuous source of fuel material (13, 33); a source of oxidizer (11, 31); a conduit (16, 36) for establishing a controllable flow of oxidizer from the source through the lance; and a sleeve (14, 34) with a layer formed of a material containing chlorine and/or fluorine, and/or a second layer formed of carbon and/or Grafoil® which contribute to focus a flame; whereby, when the hot rod is ignited and used to remove portions of a target material, the chlorine and/or fluorine in the sleeve material will react chemically with the target material to form gaseous reaction products, and the reel will provide a continuous source of fuel material.

Abstract: A tool or fluxing head for fluxing molten metal that comprises a fluxing gas supply line that communicates with the interior of an inverted plunger cup providing a hollow interior into which refining agents and other additives that are to be introduced into a molten metal can be incorporated. In use, the fluxing head is introduced into a molten metal body with the plunger cup in the inverted position. The inverted plunger cup has a closed top at the point where the gas supply line enters and an open bottom that allows molten metal to enter the inverted cup to make contact with the refining agent or other additive. Apertures are provided in the wall of the inverted plunger cup to allow gas introduced therein to escape therefrom. According to a preferred embodiment, a porous layer is provided at the top of the inverted plunger cup to allow for the escape of gas into the molten metal through the porous layer.

Abstract: An injection lance (26) for injecting hot gas into a vessel includes an elongate gas flow duct (31) which receives hot gas from a gas inlet structure (32) and an elongate central tubular structure (33) which extends within gas flow duct (31) from its rear end to its forward end. Adjacent the forward end of duct (31), central structure (33) carries a series of flow directing vanes (34) for imparting swirl to the hot gas flow exiting the duct. The wall of duct (31) downstream from gas inlet (32) is internally water cooled by flow of water through annular passages (43,44). The cooling water also flows through the interior of a duct tip (36) at the forward end of duct (31). The front end of central structure (33) which carries the swirl vanes (34) is internally water cooled by cooling water supplied forwardly through a central water flow passage (52) from a water inlet (53) at the rear of the lance through to a nose (35) of the central structure.

Abstract: A coherent jet lance and operating method wherein the need for a lance extension is eliminated using two rings of ports to deliver respectively fuel and oxidant flame envelope gases around the primary gas jets to maintain the gas jets coherent wherein the ports of the two rings are aligned on the lance face.

Abstract: A method of producing products of carbon steel or stainless steel in an electrical arc furnace-converter (8) with two metallurgical vessels (9; 10), wherein during melting, an electrode system (11) pivots above each vessel (9; 10), and during oxidation with oxygen, in each vessel, a top lance (12) and one or more side lances (13) are introduced, and wherein an immediate quality change from carbon melt to stainless melt or vice versa is effected by oxidation with oxygen with top lance (12) and/or by oxidation with oxygen with at least one side lance (13) or in reverse order during tapping periods which depend on operation of an immediately adjoining continuous casting machine (18), makes a time-independent change of the melting sequence possible.

Abstract: An assembly wherein inexpensive and essentially maintenance-free sensor means may be used in conjunction with conventional a metal making lance with minimal adaptation of the lance's structure. The assembly contemplates the use of consumable sensors that may be dispensed through a sensor feed tube disposed interiorly or exteriorly of a conventional metal making lance. The sensors may be selected to detect one or more characteristics of the metal being treated and/or operating conditions of the furnace vessel.

Abstract: In a device for atomizing liquid melts, in particular oxidic slags or glasses, including a slag tundish and an outlet opening into which a lance is immersed to inject gases or vapor while forming an annular gap, the lance (3) is comprised of two coaxial tubes (4, 5) which are separately displaceable in the axial direction and fixable in their respective axially displaced positions.

Abstract: A coherent jet lance and operating method wherein the need for a lance extension is eliminated using a single ring of ports to deliver flame envelope gases around the primary gas jets to maintain the gas jets coherent.

Abstract: This invention concerns a blowing lance and a procedure for the metallurgical treatment of molten steel in a converter with oxygen top blown over the molten steel. In order to monitor the treatment process the intention is for a temperature probe (21) to be integrated into the water-cooled lance head (2) behind the front end (11a) of the lance head and between the cooling chambers (5-10) formed in the lance head (2). The signal lines (26) of the temperature probe run through the lance body (1), more specifically, in a central protective pipe which has no fluid communication with the cooling medium or to the oxygen conducted by the lance.

Abstract: A direct smelting process for producing iron and/or ferroalloys is provided, which involves forming a molten bath in a metallurgical vessel, supplying feed materials, injecting oxygen containing gas, generating upward movement of the molten material from the molten bath, wherein the oxygen-containing gas is injected by three or more lances, and entraining into the jets of oxygen containing gas a volume of top space gas that is 2-6 times the volume of the injected gas.

Abstract: A metallurgical lance for introducing gas from above into a volume of metal in a vessel includes a head having at least one ejector formed therein. The ejector includes a Laval nozzle surrounded by a shrouding gas passage. Both the Laval nozzle and the shrouding gas passage communicate at their proximal ends with a common gas supply chamber. The shrouding gas passage communicates with the chamber via a first annular orifice member which determines the percentage split of the gas flow through the chamber between the Laval nozzle and the shrouding gas passage.

Abstract: An elongate metallurgical lance (27) for injecting solid particulate material into molten material held within a vessel (11) is disclosed. The lance includes a central core tube (31) through which to pass solid particulate material, an annular cooling jacket (32) surrounding the central core tube throughout a substantial part of its length, a coolant inlet means (52), and a coolant outlet means (53). An outer wall of a forward end section of the jacket is formed from a first material which has high heat transfer properties and can withstand external temperatures above 1100° C. for prolonged periods when the jacket is cooled by coolant flow. An outer wall of a body section of the jacket is formed from a second material that maintains its structural properties when exposed to external temperatures above 1100° C. for prolonged periods when the jacket is cooled by coolant flow, whereby the outer wall acts as a structural member that contributes to supporting the lance at these temperatures.

Abstract: A system wherein oxygen is provided to a shaft furnace in addition to the blast air, and a flame shroud is formed around the oxygen stream enabling deep penetration of the oxygen into the furnace for not only combusting carbonaceous material for generating heat but also for cutting and oxidizing metal within the furnace.

Abstract: The invention relates to a method for cooling a lance provided for converting a medium into a molten mass and/or for measuring the properties of the molten mass. A gas/liquid mixture is fed as a cooling medium into a cooling circuit which is closed up to the lance end (2) situated on the melting side. The invention provides that the gas/liquid mixture or the components thereof is/are fed and permitted to expand under pressure up to the area of the lance end (2) situated on the melting side. The invention also relates to a lance which has a mixing chamber (5, 6) connected to the cooling circuit The mixing chamber has the connections (3, 7) for a gas and liquid supply which is designed to produce the gas/liquid mixture, whereby the mixing chamber (5, 6) is connected via a pressure line (10) to at least one two-component nozzle (11) arranged in the area of the lance end (2) which is situated on the melting side.

Abstract: The invention relates to a method for producing a metal melt in a metallurgical vessel, in particular an iron or steel melt, feed substances which contain metals and/or metal oxides, being charged in solid and, if appropriate, molten form into the metallurgical vessel, the main part of the energy necessary for the melting and, if appropriate, finish-reduction of the feed substances being applied electrically and/or by the combustion and/or gasification of carbon-containing materials. The invention relates, further, to multi-functional lances for use in a method according to the invention.

Abstract: A multi-purpose, multi-oxy-fuel High Temperature Power Burner/Injector/Oxygen Lance, Mechanical System Apparatus Device, for steelmaking from recycled scrap and/or virgin ferrous charge, which can be employed in multi-oxy-fuel (natural gas; pulverized carbonaceous matter; heavy oil), especially by Oxygen Combusted mixture of Natural Gas/Pulverized Carbonaceous Matter in High Temperature Power Burner Mode, for efficient and rapid melting of solid ferrous charge (cold or preheated) in a special steelmaking Metallurgical Furnace or Open Hearth Furnace, Tandem Furnace, BOF, EAF, as its augmenting or only source of thermal energy; more than one Device in Oxygen-Natural Gas/Pulverized Carbonaceous Matter Power Burner Mode, can be employed as the only source of thermal energy in a modified, originally Electric Arc Furnace, as total replacement of Graphite Electrodes and Electric Arc System, the replacement being noticeably more primary energy efficient than the thermal energy provided by Graphite Electrode/Arc Syste

Abstract: A gas injection lance and an apparatus employing the lance for producing ferrous metal are provided. The lance has an elongated flow duct made of inner and outer concentric carbon steel tubes, a cooling water supply and return, and exterior surface which is designed to hold a frozen layer of slag on the duct, a gas inlet at a rear end of the duct, a tip joining the concentric tubes at the forward end of the duct, a non-metallic or refractory lining for the duct, and swirl-imparting member or members located in the duct for imparting swirl in the gas flow through the forward end of the duct.

Abstract: A method for blowing oxygen in a converter uses a top-blown lance having a Laval nozzle installed on its tip. The Laval nozzle has a back pressure of the nozzle Po(kPa) satisfying a formula, Po=FhS/(0.00465·Dt2), with respect to a oxygen-flow-rate FhS(Nm3/hr) per hole of the Laval nozzle determined from the oxygen-flow-rate FS(Nm3/hr) in a high carbon region in a peak of decarburization and a throat diameter Dt(mm). An exit diameter De of the Laval nozzle satisfies the following formula with respect to the back pressure of the nozzle Po(kPa), an ambient pressure Pe(kPa), and the throat diameter Dt(mm).

Abstract: A direct smelting process for producing metal from a metalliferous feed material is disclosed. The direct smelting process is a molten bath-based process in which smelting occurs predominantly in the metal layer, carrier gas/metalliferous feed material/solid carbonaceous material are injected into the metal layer via lances/tuyeres, and oxygen-containing gas is injected into the top space above the molten bath and post-combusts reaction gases released from the bath. The injection of metalliferous feed material and solid carbonaceous material causes molten material to be projected from the molten bath as splashes, droplets and streams and to form a transition zone. The process is characterized by forming a pipe of a solid material on an outlet end of at least one lance/tuyere while injecting the metalliferous feed material and the carbonaceous material through the lances/tuyeres and thereby extending the effective length of the lance/tuyere or the lances/tuyeres.

Abstract: A method and apparatus for establishing one or more coherent jets from a lance wherein liquid fuel is provided into a recession on the lance face along with motive gas, and is used to generate a flame shroud to maintain jet coherency.

Abstract: Apparatus for injecting gas into a vessel comprises a lance 26 having a gas flow duct 31 extending longitudinally from a rear end to a forward end (36) from which to discharge gas from the duct. An elongate body 38 disposed within the forward end of the duct is fitted with flow directing vanes 39 to impart swirl to the discharging gas. The tip 44 is internally cooled by water supplied and returned through supply and return passages 52, 56. Cooling water is also passed through internal cooling passages 66, 75, 76, 87 within vanes 39 and central body 38 via water supply and return passage 60 within the duct.

Abstract: A system for establishing and maintaining a supersonic coherent gas jet, effective with either an oxidizing or an inert gas, employing a converging/diverging nozzle for establishment of a non-disruptive initial supersonic velocity, and a slower moving defined triple layered flame envelope coaxial with the jet for effective maintenance of the supersonic velocity. The invention is particularly useful for providing gas into a pool of liquid.

Abstract: The invention relates to a method for feeding solids into metal or steel melts whereby granular solids required during the analysis adjustment are fed in a predetermined quantity into the turbulent regions of the metal melt in a dense flow process by means of a pneumatic conveying device in order to achieve a high output while avoiding expensive and complex measures associated with lances and capital-intensive investments for injection devices and lance-moving devices.

Abstract: Method and device to feed tuyeres in an electric furnace, the tuyeres comprising a central conduit to deliver a comburent gaseous substance and a peripheral conduit to deliver a cooling gaseous substance, the method providing to send to the central conduit a comburent mixture consisting of oxygen and neutral gas (N2, Ar, etc.) in defined percentages, the oxygen and the neutral gas being fed, for each of the tuyeres, to a mixing device with a high mixing capacity, at least the pressure of the neutral gas being able to be adjusted on the relative feed line so as to modulate the pressure of the mixture according to the characteristics of the melting process.

Abstract: A lance is provided for processing molten metal baths located in metallurgical tanks, and for heating the tanks. A first lance body is displaceable in a second lance body. A mechanism is provided for displacing the first lance body relative to the second lance body such that in a raised burner position of the first lance body, burner nozzles disposed in the second lance body are uncovered by the first lance body and are axially spaced from the lance mouth of the first lance body to receive gas discharge from the lance mouth and to allow burner operation. In a lowered blower position of the first lance body, the burner nozzles are covered thereby. The mechanism for displacing the lance bodies relative to one another permits infinitely variable spacing of the burner nozzles from the lance mouth that is provided for the discharge of gas.

Abstract: A multi-function lance for insertion into a vacuum degassing chamber, includes a top-blown oxygen lance provided as a path for gaseous oxygen. A nozzle is provided at a downstream end of the oxygen path used for blowing oxygen onto a molten metal. A water-cooled jacket surrounds the outer periphery of the top-blown oxygen lance. At least a set of paths for a fluid fuel and a gas for burning the fuel is positioned in a multi-function lance, namely in the water-cooled jacket, and a combustion burner is provided at a downstream end of the path. By using the multi-function lance according to the present invention, not only a safer and shorter preheating operation is enabled, but also oxygen lancing, temperature elevation of molten steel, and heating of the vacuum degassing apparatus itself are smoothly realized.

Abstract: An elongate metallurgical lance (27) for injecting solid particulate material into molten material held within a vessel (11) is disclosed. The lance includes a central core tube (31) through which to pass solid particulate material, an annular cooling jacket (32) surrounding the central core tube throughout a substantial part of its length, a coolant inlet means (52), and a coolant outlet means (53). An outer wall of a forward end section of the jacket is formed from a first material which has high heat transfer properties and can withstand external temperatures above 1100° C. for prolonged periods when the jacket is cooled by coolant flow. An outer wall of a body section of the jacket is formed from a second material that maintains its structural properties when exposed to external temperatures above 1100° C. for prolonged periods when the jacket is cooled by coolant flow, whereby the outer wall acts as a structural member that contributes to supporting the lance at these temperatures.

Abstract: A lance which may be used to generate a longer coherent gas jet having inflowing and outflowing coolant fluid passages which are in flow communication and which straddle the flame envelope fluid passages, all of which are coaxial with the main passageway.

Abstract: Device and relative method to inject technological gases and solid material in powder form, in a furnace used in steel and metallurgical melting processes, comprising an emission element including an outlet mouth arranged at a certain distance from the liquid bath, said emission element being innerly shaped as a double nozzle, respectively first and second, the first nozzle having a convergent/divergent conformation defined by a neck and being predisposed for the emission of a jet of gas at supersonic speed, said second nozzle having at the end a conformation convergent towards the axis of the emission element and being pre-disposed, according to the step of the melting process in progress, for the emission of a jet at subsonic speed either of technological gases alone, such as for example oxygen, or of solid material in powder form on a gassy vehicle, or of liquid in atomized form.

Abstract: The present invention provides a simplified ladle refining process capable of efficiently heating a molten steel in a short period of time while scattering and adhesion of splashes and erosion of refractories are suppressed. A simplified ladle refining process for refining a molten steel in a ladle comprising inserting an immersion snorkel into a ladle and blowing an oxidizing gas onto the surface of a molten steel within the immersion snorkel through a lance while the molten steel is being stirred by blowing an inert gas through the bottom of the ladle, wherein the lance has a ratio (d0/dt) of a nozzle outlet diameter d0 (mm) to a nozzle throat diameter dt (mm) of from 1.2&agr; to 2.5&agr; wherein &agr; is defined as a function of a back pressure.

Abstract: An arrangement wherein a coherent jet is established proximate to a powder injection system and the coherent jet not only provides for gas delivery but also serves to improve the efficiency of the delivery of powder from the powder injection system.

Abstract: There is disclosed a quick change plug and socket blow lance for use in steel conversion. To expedite exchange of an exhausted lance body (2) the lance body (2) has a plug (4) formed at an upper end adapted for reception in a socket (3) formed in a head (1). The socket and head are provided with various sealing surfaces whereby coolant water and oxygen for the conversion process can reliably be delivered to passages in the lance body (2). A locking mechanism is provided whereby the plug (4) can quickly be secured into the head socket (3) and separated after use. The locking mechanism consists of a plurality of circumferentially spaced projections (7) formed on a rotatable head ring (5) mounted at the mount of the socket (3). A lance body ring is secured to the lance body immediately below the plug (4) and provides a plurality of circumferentially spaced flange segments (8a) separated by gaps (8) through which the projections can pass as the plug (4) is inserted axially into the socket (3).

Abstract: A lance tip assembly for a water-cooled lance as well as a method for constructing same. The lance tip assembly includes a first component of solid cast metal which is secured to a second or lower component of forged metal. Each active material discharge nozzle of the combined forged and cast lance tip assembly is constructed in part of the first cast component and in part of the second forged component. Only a single bond is required to join the first and second component at each nozzle site. The first and second components are fabricated to include structural features which individually and collectively promote high coolant water flow velocity through the lance tip and substantially uniform cooling of face of the lance tip.

Abstract: The use of oxygen lance tubes 12 for refining in connection with steel production is simplified and configured more safely in that the sealing casing 14 is allocated a slidable pressure piston 15 in which pressure media act on the pressure casing 14 to a limited extent, thus improving the mounting of the lance tube 12; the latter is fixed from the other side over the pressure casing 4 pushed on to the collet 3. Upon activation of the adjusting facility 11, regardless of whether it is a pneumatic or manually operated adjusting facility 11, the pressure casing 4 slides down from the collet 3 and the interior space 16 is simultaneously connected with the atmosphere through a bypass 17 with a shut-off valve 18. Any excessive oxygen pressure possibly developing here, for example as a consequence of a lance tube 12 blocked by slag, may be rapidly reduced without endangering the operating crew.

Abstract: A system for establishing a plurality of coherent gas jets proximate one another using a single lance wherein plurality of gas jets are ejected from a corresponding plurality of nozzles in a lance and a flame envelope is established around the plurality of gas jets, and the jets remain distinct and do not coalesce for their length.

Abstract: A method and device for positioning the mouth of a consumable lance that conveys gaseous and/or solid media into a metallurgical vessel containing liquid metal. The lance is guided tangentially to the furnace vessel in a plane which lies above the liquid level of the metal situated inside the vessel. In the mouth area of the lance outside the vessel, the lance is bent toward the vessel interior through a predetermined radius in order to position the lance mouth in the shape of a fan. The lance is then pushed through the side wall of the vessel into the interior of the same to reach or maintain a desired position of the lance mouth.

Abstract: A method of and an apparatus for the production of steel utilizing a single vessel for the electric arc smelting of scrap, directly reduced iron or pig iron in solid form, and for the oxygen blowing of the resulting melt through an oxygen lance introduced via a tower-shaped part of the roof. Another part of the roof can pivot to allow charging of the furnace with solids and the tower can be provided with a funnel enabling a molten iron charge to be fed to the furnace.

Abstract: An oxygen lance assembly includes a lance body which can be coupled and decoupled from a head through the use of a plug and socket junction. The plug part of the junction can be located on the lance body and provided with a plurality of axially spaced cylindrical male sealing surfaces. These are adapted to mate with corresponding female sealing surfaces provided in the head. The sealing surfaces mate with a clearance and the required seal is achieved by mounting O-rings exclusively on each male sealing surface. This provides for convenient inspection of the O-rings. Damage to the O-rings caused by vibration is prevented by cylindrical guide surfaces having a close sliding fit which serve to keep the plug part coaxial in the socket. Alignment of the plug in the socket is achieved by increasing the radius of each cylindrical sealing surface the further it is from the top of the socket via frusto-conical guide surfaces.

Abstract: A lance which may be used to establish a long coherent gas jet which includes a primary passageway having a converging/diverging nozzle, and two radially spaced secondary passageways for establishing a flame barrier, each of the passageways communicating with an injection space defined by a protective jacket.

Abstract: A device for coupling a blow lance with a header is disclosed, in which the force required for producing a sealing joint between the header (2) and the lance (4) is exerted by a cooling fluid and/or a blowing fluid. In a preferred embodiment, said cooling fluid and/or blowing fluid acts via a pressure surface (32) on the joint between the header (2) and the lance (4), the pressure surface being integral with a piston (22) which transmits the pressure to said joint. The lance has preferably a first coupling surface (12), while the header (2) has a second coupling surface (14), and one of said coupling surfaces (12 or 14) is integral with said piston (22).