A tuyere comprising an inner tube including a lower section having a first diameter, an upper section having a second diameter smaller than the first diameter, and a converging transition section having a converging angle from 15 to 35 connecting the lower section to the upper section, the inner tube terminating in an inner nozzle at a downstream end of the upper section; and an outer tube surrounding the inner tube so as to create an annulus there between, the outer tube including a lower section having a third diameter larger than the first diameter, an upper section having a fourth diameter smaller than the third diameter but larger than the second diameter, and a converging transition section having connecting the lower section to the upper section, the outer tube terminating in an outer nozzle at a downstream end of the upper section.

The invention relates to a gas purging device for installation in a metallurgical vessel, said device having the following features in a position installed in the bottom of the metallurgical vessel: a lower, largely gas-tight base part, a gas line runs in the base part from a first end in the region of a first outer face of the base part to a second end in the region of a second outer face of the base part, the second end of the gas line is formed as a first portion of a coupling, a second portion of a coupling is located in the region of an outer connection face of a functional part, by means of which the functional part rests against the base part, a gas distribution device runs in the functional part from the second portion of the coupling, through the functional part, to at least one free surface of the functional part formed as a gas outlet face, the base part and functional part are each made of a refractory ceramic material.

A method of operating a BOF bottom stir tuyere having an inner nozzle surrounded by an annular nozzle, including during a hot metal pour phase and a blow phase, flowing an inert gas through both nozzles; during a tap phase, initiating a flow of a first reactant through the inner nozzle and a flow of a second reactant through the annular nozzle, and ceasing the flow of inert gas through the nozzles, wherein the first and second reactants includes fuel and oxidant, respectively, or vice-versa, such that a flame forms as the fuel and oxidant exit the tuyere; during a slag splash phase, continuing the flows of fuel and oxidant to maintain the flame; and after ending the slag splash phase and commencement of another hot metal pour phase, initiating a flow of inert gas through both nozzles and ceasing the flows of the first and second reactants.

A method of operating a BOF bottom stir tuyere having an inner nozzle surrounded by an annular nozzle, including during a hot metal pour phase and a blow phase, flowing an inert gas through both nozzles; during a tap phase, initiating a flow of a first reactant through the inner nozzle and a flow of a second reactant through the annular nozzle, and ceasing the flow of inert gas through the nozzles, wherein the first and second reactants includes fuel and oxidant, respectively, or vice-versa, such that a flame forms as the fuel and oxidant exit the tuyere; during a slag splash phase, continuing the flows of fuel and oxidant to maintain the flame; and after ending the slag splash phase and commencement of another hot metal pour phase, initiating a flow of inert gas through both nozzles and ceasing the flows of the first and second reactants.

A lance comprising a lance body including a lance head connected to said lance body and comprising a nozzle body having a central strut having bore hole; a camera assembly, such as an optical or infrared camera assembly, received in said bore hole for monitoring the temperature of said lance head or molten heat in which the lance is inserted; and a protective pipe pressurized with a gas disposed in the bore and surrounding said camera assembly.

A lance comprising a lance body including a lance head connected to said lance body and comprising a nozzle body having a central strut having bore hole; a camera assembly, such as an optical or infrared camera assembly, received in said bore hole for monitoring the temperature of said lance head or molten heat in which the lance is inserted; and a protective pipe pressurized with a gas disposed in the bore and surrounding said camera assembly.

A method of operating a BOF bottom stir tuyere having an inner nozzle surrounded by an annular nozzle, including during a hot metal pour phase and a blow phase, flowing an inert gas through both nozzles; during a tap phase, initiating a flow of a first reactant through the inner nozzle and a flow of a second reactant through the annular nozzle, and ceasing the flow of inert gas through the nozzles, wherein the first and second reactants includes fuel and oxidant, respectively, or vice-versa, such that a flame forms as the fuel and oxidant exit the tuyere; during a slag splash phase, continuing the flows of fuel and oxidant to maintain the flame; and after ending the slag splash phase and commencement of another hot metal pour phase, initiating a flow of inert gas through both nozzles and ceasing the flows of the first and second reactants.

A method of operating a BOF bottom stir tuyere having an inner nozzle surrounded by an annular nozzle, including during a hot metal pour phase and a blow phase, flowing an inert gas through both nozzles; during a tap phase, initiating a flow of a first reactant through the inner nozzle and a flow of a second reactant through the annular nozzle, and ceasing the flow of inert gas through the nozzles, wherein the first and second reactants includes fuel and oxidant, respectively, or vice-versa, such that a flame forms as the fuel and oxidant exit the tuyere; during a slag splash phase, continuing the flows of fuel and oxidant to maintain the flame; and after ending the slag splash phase and commencement of another hot metal pour phase, initiating a flow of inert gas through both nozzles and ceasing the flows of the first and second reactants.

To improve the position of a cylindrical ceramic hollow body the invention relates to a securing device for use with a gas purging brick, where the securing device has the following characteristics in its operational position: A base body which, with its bottom and a circumferential wall, defines a cylindrical space with a corresponding central longitudinal axis, the bottom features an opening whose longitudinal axis aligns with the central longitudinal axis the bottom features a ring-shaped channel which extends concentrically around the opening. at least an inner wall of the channel which is adjacent to the opening consists of a material which is plastically ductile under the application of pressure, a ring-shaped compact whose radial wall cross-section increases in size upwards from a lower free end, so that the inner wall of the channel deforms plastically, thereby reducing the cross section of the opening, after the compact is pressed into the channel.

To improve the position of a cylindrical ceramic hollow body the invention relates to a securing device for use with a gas purging brick, where the securing device has the following characteristics in its operational position: A base body which, with its bottom and a circumferential wall, defines a cylindrical space with a corresponding central longitudinal axis, the bottom features an opening whose longitudinal axis aligns with the central longitudinal axis the bottom features a ring-shaped channel which extends concentrically around the opening. at least an inner wall of the channel which is adjacent to the opening consists of a material which is plastically ductile under the application of pressure, a ring-shaped compact whose radial wall cross-section increases in size upwards from a lower free end, so that the inner wall of the channel deforms plastically, thereby reducing the cross section of the opening, after the compact is pressed into the channel.