Electric furnace and method for manufacturing cast iron using said electric furnace.

Description

1 / 31 “ELECTRIC FURNACE AND METHOD FOR MANUFACTURING CAST IRON USING SAID ELECTRIC FURNACE” Separated from BR112023015975-0, filed on 01 / 27 / 2022 FIELD OF THE INVENTION

[001] The present disclosure relates to a burner with an imaging device and, in particular, a burner with an imaging device that allows an operator to operate the burner while observing the smelting of a cold iron source to produce cast iron. The present disclosure also relates to an electric furnace provided with a burner with an imaging device and operable to efficiently produce cast iron by smelting from a cold iron source. Furthermore, the present disclosure relates to a method of using an electric furnace to efficiently produce cast iron. The burner with the imaging device may be installed as appropriate in an electric furnace operable to produce cast iron from a cold iron source. BACKGROUND OF THE INVENTION

[002] When an electric furnace is used to melt cold iron sources, such as ferrous scrap, to produce pig iron, a cold iron source near an electrode melts rapidly in the melting chamber, but a cold iron source far from the electrode, a so-called cold spot, melts more slowly, resulting in unequal melting rates of cold iron sources in the melting chamber. A resulting problem is that the total operating time of the electric furnace is determined by the melting rate of the cold iron source at the cold spot.

[003] To eliminate uneven melting rates of cold iron sources and to melt cold iron sources in the melting chamber in a well-balanced manner, a burner (auxiliary combustion burner) is installed in a position where a cold spot is likely to occur. The burner accelerates the Petition 870260059225, dated 06 / 17 / 2026, page 11 / 84 2 / 31 Cold iron source casting at the cold point.

[004] For example, document JP H10-9524 A (PTL 1) describes an electric furnace auxiliary combustion burner with a triple-tube structure according to which oxygen gas for splashing unburned materials and cutting scrap is injected from a central location, fuel is injected from the periphery of the oxygen gas, and combustion oxygen gas is injected from the periphery of the fuel. According to the PTL 1 auxiliary combustion burner, a restriction portion is provided at one end of a central oxygen gas injection tube to increase the speed of the central oxygen gas injection, and a swirling vane is provided in an annular space formed by a fuel injection tube and a combustion oxygen gas injection tube to impart a swirling motion to the combustion oxygen gas injected from an outermost circumference.

[005] With the use of the auxiliary burner described in PTL 1, cold iron sources in a casting chamber can be melted more uniformly. However, since it is not possible to visually check the state of a cold iron source in the casting chamber when operating the auxiliary burner, determining whether the cold iron source has been sufficiently melted depends on the operator's experience. For example, if a cold iron source present at a cold spot is still not melted when using the auxiliary burner, the casting efficiency cannot be sufficiently increased. Furthermore, overheating a cold iron source at a cold spot will not only eliminate the cold spot but also promote a hot spot, resulting in uneven molten iron temperature in the casting chamber.

[006] The interior of the smelting chamber could, of course, be checked by opening a slag door, furnace lid, or something similar. No Petition 870260059225, dated 06 / 17 / 2026, page 12 / 84 3 / 31 However, when open, excess air enters the furnace from outside the furnace, resulting in significant heat loss. Furthermore, an operator must get close to the furnace body, which can be disastrous in the event of an explosive boil-up of molten iron or slag. Therefore, optimizing the ignition and quenching time of a burner is difficult in practice, and efficient molten iron production has been a challenge.

[007] As a method for observing the interior of a furnace, JP H07103670 A (PTL 2) proposes a monitoring device inside the furnace that uses a television camera to capture images of the furnace interior and monitor internal conditions through television images. LIST OF QUOTES Patent Literature PTL 1: JP H10-9524 A PTL 2: JP H07-103670 A BRIEF DESCRIPTION OF THE INVENTION (TECHNICAL PROBLEM)

[008] However, when the inventors attempted to observe a cold iron source at a cold point being melted by a burner by actually inserting the monitoring device disclosed in PTL 2 into an electric furnace, a lens tip of the monitoring device burned in the high-temperature environment of the electric furnace. Furthermore, a situation was observed where the lens tip was covered with molten slag that boiled away, making further monitoring impossible.

[010] In view of the problems described above, it would therefore be useful to provide a burner with an operable imaging device to clearly observe the interior of a furnace in which an object is heated while the object is being heated by the burner. In addition, it would also be useful to provide an electric furnace supplied with the burner with the Petition 870260059225, dated 06 / 17 / 2026, page 13 / 84 4 / 31 image device, the electric furnace being operable to efficiently produce cast iron from a cold iron source and a method for efficient production of cast iron using the electric furnace. (SOLUTION TO THE PROBLEM)

[011] As a result of studying the above problems, the inventors discovered that when a burner comprises a lens and an imaging device, and has a defined multi-tube structure, the burner can be used efficiently while providing a good visual check of the interior of a furnace in which an object is heated by the burner. The inventors also discovered that when the burner is used to efficiently produce cast iron from a cold iron source, the production efficiency can be increased and the rate of electrical energy consumption required for production can be reduced.

[012] The main features of the present disclosure are as follows.

[013] [1] A burner with an imaging device, the burner burning gaseous fuel to form a flame, the burner comprising: a lens; the imaging device disposed behind the lens, wherein one side of the lens towards an object to be pictured is defined as front and one side opposite the lens to the object to be pictured along an optical axis of the lens is defined as rear; and a multi-tube structure comprising: an inner tube enclosing the lens; an outer tube encircling the inner tube, larger in diameter than the inner tube and separated from the inner tube by a lens coolant passage; a gaseous fuel tube radially disposed outward from the outer tube and operable to inject gaseous fuel in a front direction of the lens; a combustion support gas tube radially disposed outward from the outer tube and operable to inject combustion support gas in the direction Petition 870260059225, dated 06 / 17 / 2026, p. 14 / 84 5 / 31 front of the lens; and a cooling tube located on the outermost part of the multi-tube structure that surrounds the gaseous fuel tube and the combustion support gas tube.

[014] According to the above revelation, a front of the lens is on the side of the object to be pictured, in other words, the side where the object to be heated by the burner is positioned, and also the direction of the flame formed from the burner. For example, when the burner is installed through a furnace wall of an electric furnace, the direction is inward toward the electric furnace. A back of the lens is the opposite side along the optical axis of the lens from the object to be pictured. For example, when the burner is installed through a furnace wall of an electric furnace, the direction is outward toward the electric furnace.

[015] [2] The burner with an image device according to [1] wherein the gaseous fuel tube is larger in diameter than the outer tube, surrounds the outer tube and is separated from the outer tube by a gaseous fuel passage, the combustion support gas tube is larger in diameter than the gaseous fuel tube, surrounds the gaseous fuel tube and is separated from the gaseous fuel tube by a combustion support gas passage, the cooling tube is larger in diameter than the combustion support gas tube, surrounds the combustion support gas tube and is separated from the combustion support gas tube by a burner body coolant passage, and the inner tube, the outer tube, the gaseous fuel tube, the combustion support gas tube and the cooling tube are arranged coaxially.

[016] [3] The burner with an image device according to [2], in which tube openings in an axial direction of the tube are arranged in the order of inner tube, outer tube and gaseous fuel tube along the forward direction of the lens. Petition 870260059225, dated 06 / 17 / 2026, page 15 / 84 6 / 31

[017] [4] An electric furnace provided with the burner as described in any one of [1] to [3], the electric furnace being operable for melting a cold iron source to produce pig iron.

[018] [5] A method for producing cast iron by casting from a cold iron source using an electric furnace provided with the burner as described in any one of [1] to [3], wherein the operating conditions of the burner are controlled based on visual information obtained from the burner.

[019] [6] The method for producing cast iron according to [5], wherein when visual information obtained from the burner confirms the presence of an adherent material on a front surface of the lens, combustion support gas is injected from the combustion support gas tube or combustion support gas is injected from the combustion support gas tube and gaseous fuel is injected from the gaseous fuel tube, in order to remove the adherent material from the lens. (ADVANTAGEOUS EFFECT)

[020] According to the present disclosure, when heating an object with the burner, the interior of the furnace where the object (object to be depicted) is heated can be clearly observed.

[021] When the burner is operated while observing the interior of the furnace where the object is heated, for example, when melting a cold iron source in an electric furnace to produce cast iron, a cold iron source at a cold point can be melted efficiently and the temperature of the cast iron can be controlled uniformly, which is effective in reducing production costs and has an exceptional effect on the industry. BRIEF DESCRIPTION OF THE DRAWINGS

[022] In the attached drawings:

[023] Figure 1 is a longitudinal cross-sectional view illustrating a Petition 870260059225, dated 06 / 17 / 2026, p. 16 / 84 7 / 31 burner with an imaging device according to an embodiment of the present disclosure, side view;

[024] Figure 2A and Figure 2B are longitudinal sectional views illustrating a burner with an imaging device according to at least one embodiment of the present disclosure, viewed from the front; Figure 2A illustrates an example in which each tube is arranged coaxially, and Figure 2B illustrates an example in which gaseous fuel tubes and combustion support gas tubes are arranged non-coaxially;

[025] Figure 3 is a longitudinal cross-sectional view illustrating a burner with an imaging device according to an embodiment of the present disclosure, installed in an electric furnace; and

[026] Figure 4 is a cross-sectional view illustrating a burner with an imaging device according to an embodiment of the present disclosure, installed in an electric furnace. DETAILED DESCRIPTION OF THE INVENTION

[027] The following describes modalities of the present disclosure.

[028] The following description merely indicates examples of preferred embodiments and the present disclosure is in no way limited to the examples described. (BURNER)

[029] According to the present disclosure, a burner including a lens and an imaging device has a defined multi-tube structure, including an inner tube enclosing the lens, an outer tube enclosing the inner tube, an operable gaseous fuel tube for injecting gaseous fuel, an operable combustion support gas tube for injecting combustion support gas, and an outermost cooling tube. The defined structure of the burner with the imaging device allows for clear observation of the heating of an object by the burner, even in Petition 870260059225, dated 06 / 17 / 2026, page 17 / 84 8 / 31 very high temperatures, above 1000 °C. Therefore, when using the burner, operating conditions can be controlled while visually checking the heating conditions due to the burner at very high temperatures, such as in an electric furnace, for example. As a result, for example, when producing cast iron from a cold iron source in an electric furnace, the melting efficiency of the cold iron source by the burner can be improved and production costs can be reduced. The burner is particularly suitable for use as an auxiliary burner to accelerate the melting of an unmelted cold iron source at a so-called cold spot during the production of cast iron from cold iron sources in an electric furnace.

[030] What follows is a description of a preferred embodiment of the burner, with reference to the drawings. (LENS)

[031] A burner (1) includes a lens (7) and an image device (8) behind the lens (7). The lens (7) is preferably a relay lens comprising multiple lenses. A relay lens allows for axial length separation of a front surface of the lens (7) from the image device (8). For example, when installing the burner (1) in an electric furnace (90), this allows the front of the lens (7) to be disposed inside the furnace to clearly capture the object to be pictured, while at the same time allowing the image device (8) to be disposed outside the furnace to protect the image device (8) from high heat and to simplify maintenance. (IMAGE DEVICE)

[032] The imaging device (8) is provided behind the lens (7) and captures and, as needed, records an image of the object formed by the lens (7). For example, when the burner (1) is installed in the furnace Petition 870260059225, dated 06 / 17 / 2026, page 18 / 84 9 / 31 electric (90), the imaging device (8) is preferably installed outside the furnace of the electric furnace (90), as described above. The imaging device (8) is typically a camera and is preferably protected by an enclosure (83). To further protect the imaging device (8) from the heat of the electric furnace (90), an imaging device coolant (80) preferably flows through a coolant supply port (81) and a coolant outlet (82) provided anywhere in the enclosure (83). The imaging device coolant (80) may be a liquid, such as water, or any gas, but for ease of handling, it is preferably a gas and, more preferably, air or an inert gas, such as nitrogen.

[033] The video captured by the imaging device (8) is usually transmitted via a cable connection (not shown) to a monitor or recording device (not shown) in an operating room where an operator operates. (INNER TUBE)

[034] The inner tube (6) encloses the lens (7). The inner tube (6) encloses the lens (7), thus securing the lens (7) and physically protecting the lens (7) from the surrounding environment, such as heat, adhesive materials and the like. The inner tube (6) may be connected to the housing (83) to further protect the imaging device (8). An outer diameter of the inner tube (6) is not limited to any specific value, but from a perspective of ensuring a lens coolant flow rate (70) described below, while keeping costs low, the outer diameter is preferably 100 mm or less and generally 20 mm or more.

[035] The inner tube (6) may have a tubular shape and the material properties must be selected appropriately in relation to the ambient temperature and the resistance of the installation site. From a Petition 870260059225, dated 06 / 17 / 2026, page 19 / 84 10 / 31 from a cost perspective, carbon steel, stainless steel or similar are preferable.

[036] When the lens (7) is a relay lens, the inner tube (6) and the lens (7) are preferably arranged coaxially. (OUTER TUBE)

[037] The outer tube (5) is larger in diameter than the inner tube (6), encircles the inner tube (6) and is separated from the inner tube (6) by a lens coolant passage. By using a multi-tube structure with the outer tube (5) encircling the inner tube (6), the lens (7) can be better protected from the intense heat of the surrounding environment. In addition, the outer tube (5) encircles the inner tube (6) separated by the lens coolant passage, allowing the lens coolant (70) to flow through the passage into a space between the inner tube (6) and the outer tube (5), further protecting the lens (7) from the intense heat of the surrounding environment.For example, when the lens coolant (70) is discharged in a forward direction from the lens (7) through a coolant supply port (71) and a coolant outlet (72) arranged as illustrated by the outer tube (5) in Figure 1, the lens coolant (70) can be effectively used to blow away molten iron (96) and molten slag splashes from the electric furnace (90) and thus prevent the adhesion and deposition of the same on the front surface of the lens.

[038] For example, in order to discharge the lens coolant (70) into the electric furnace (90) without affecting the composition of the cast iron (96) in the furnace (90), the lens coolant (70) is preferably a gas and, more preferably, air or an inert gas such as nitrogen. The flow rate of the lens coolant (70) is preferably 50 NL / min or more. The unit “NL / min” is a flow rate unit commonly used in the current technical field and can generally be treated as “L / min”. Petition 870260059225, dated 06 / 17 / 2026, page 20 / 84 11 / 31

[039] The outer tube (5) can be connected to the housing (83) to further protect the imaging device (8). An inner and outer diameter of the outer tube (5) are not limited to any specific value, but from the perspective of ensuring the flow of the lens coolant (70) while keeping costs low, the inner diameter is preferably 120 mm or less and can be 30 mm or more. From the point of view of keeping costs low while ensuring a flow of a gaseous fuel (40), described later, the outer diameter is preferably 40 mm or more.

[040] The outer tube (5) may have a tubular shape and the material properties must be appropriately selected in relation to the ambient temperature and the resistance of the installation site. From a cost perspective, carbon steel, stainless steel or similar materials are preferable.

[041] When the lens (7) is a relay lens, the outer tube (5), the inner tube (6) and the lens (7) are preferably arranged coaxially. An opening in an axial direction of the outer tube (5) (on paper, in Figure 1, a tip on the left side of the outer tube (5)) is preferably located further forward of the lens (7) than an opening in an axial direction of the inner tube (6) (on paper, in Figure 1, a tip on the left side of the inner tube (6)). By repositioning the front surface of the lens (7) in this way, adhesion and deposition on the front surface of the lens by molten iron (96) and splashes of molten slag from inside the furnace of the electric furnace (90) can be better avoided. (GASEOUS FUEL PIPE)

[042] The gaseous fuel tube (4) is radially arranged outward from the outer tube (5) and is operable to inject the gaseous fuel (40) in the forward direction of the lens (7). The injected gaseous fuel (40) is Petition 870260059225, dated 06 / 17 / 2026, page 21 / 84 12 / 31 burned in the electric furnace (90), for example, forming a flame from the burner (1) to reach and melt a cold iron source (94) that is not molten.

[043] The gaseous fuel tube (4) may be larger in diameter than the outer tube (5), enclosing the outer tube (5) and separated from the outer tube (5) by a gaseous fuel passage, as illustrated in Figure 1 and Figure 2A, and may be arranged individually or in plurality near the outer circumference of the outer tube (5), as illustrated in Figure 2B. Arrangements illustrated in Figure 1 and Figure 2A are preferred. By using a multiple tube structure with the gaseous fuel tube (4) further enclosing the outer tube (5), the lens (7) may be additionally protected from the intense heat of the surrounding environment.Furthermore, because the gaseous fuel tube (4) surrounds the outer tube (5) separated by a gaseous fuel passage, the gaseous fuel (40) can be injected through the passage into a space between the outer tube (5) and the gaseous fuel tube (4) that surrounds the outer tube (5), and therefore, for example, the molten iron (96) and molten slag splashing from the furnace of the electric furnace (90) can also be blown away by the gaseous fuel (40), and this can be effectively used to prevent adhesion and deposition of the same on the front surface of the lens. For example, the gaseous fuel (40) can be injected in front of the lens (7) through a gaseous fuel supply port (41) and a gaseous fuel injection port (42) arranged as illustrated by the gaseous fuel tube (4) in Figure 1.

[044] As gaseous fuel (40), examples include liquefied petroleum gas (LPG), liquefied natural gas (LNG), hydrogen, steelmaking byproduct gas (C gas, B gas, etc.) and mixed gas comprising two or more of these gases, each of which may be used alone or in Petition 870260059225, dated 06 / 17 / 2026, page 22 / 84 13 / 31 combination with another gas.

[045] The gaseous fuel flow rate (40) is preferably 150 NL / min or more. The gaseous fuel pipe (4) can be fixed in connection with the outer pipe (5). An inner and outer diameter of the gaseous fuel pipe (4) are not limited to any specific value, but from the perspective of ensuring the gaseous fuel flow rate (40) and reducing costs, when the gaseous fuel pipe (4) surrounds the outer pipe (5), the inner diameter is preferably 140 mm or less and may be greater than 40 mm. From the point of view of keeping costs low while ensuring a combustion support gas flow rate (30) described below, the outer diameter is preferably 50 mm or more.

[046] The gaseous fuel pipe (4) may have a tubular shape and the material properties must be selected appropriately in relation to the ambient temperature and the resistance of the installation site. From a cost perspective, carbon steel, stainless steel or similar materials are preferable.

[047] When the lens (7) is a relay lens, the gaseous fuel tube (4), the outer tube (5), the inner tube (6) and the lens (7) are preferably arranged coaxially. An opening in an axial direction of the gaseous fuel tube (4) (on paper, in Figure 1, a tip on the left side of the gaseous fuel tube (4)) is preferably located further forward of the lens (7) than the opening in the axial direction of the outer tube (5) (on paper, in Figure 1, the tip on the left side of the outer tube (5)). By further receding the front surface of the lens (7) in this way, adhesion and deposition on the front surface of the lens by molten iron (96) and splashes of molten slag from inside the furnace of the electric furnace (90) can be further avoided. (COMBUSTION SUPPORT GAS PIPE) Petition 870260059225, dated 06 / 17 / 2026, page 23 / 84 14 / 31

[048] The combustion support gas tube (3) is radially arranged outward from the outer tube (5) and is operable to inject the combustion support gas (30) ahead of the lens (7). The injected combustion support gas (30) promotes the combustion of the gaseous fuel (40) described above, and the gaseous fuel (40) is burned in the electric furnace (90), for example, forming a flame from the burner (1) to reach and melt the cold iron source (94) that is not molten.

[049] The combustion support gas tube (3) may be larger in diameter than the gaseous fuel tube (4), enclosing the gaseous fuel tube (4) and separated from the gaseous fuel tube (4) by a combustion support gas passage, as illustrated in Figure 1 and Figure 2A, and may be arranged individually or in plurality near the outer circumference of the outer tube (5), as illustrated in Figure 2B. Arrangements illustrated in Figure 1 and Figure 2A are preferred. By using a quadruple tube structure with the combustion support gas tube (3) additionally enclosing the gaseous fuel tube (4), the lens (7) may be further protected from the intense heat of the surrounding environment.Furthermore, because the combustion support gas tube (3) surrounds the gaseous fuel tube (4) separated by the combustion support gas passage, the combustion support gas (30) can be injected through the passage into a space between the gaseous fuel tube (4) and the combustion support gas tube (3) around the gaseous fuel tube (4) and therefore, for example, molten iron (96) and molten slag splashes from the electric furnace furnace (90) can be blown away by the combustion support gas (30) to better prevent adhesion and deposition of the same on the front surface of the lens. For example, the combustion support gas (30) can be injected in front of the lens (7) through a supply port. Petition 870260059225, dated 06 / 17 / 2026, page 24 / 84 15 / 31 of combustion support gas (31) and a combustion support gas injection port (32) arranged as illustrated by the combustion support gas tube (3) in Figure 1.

[050] As the combustion support gas (30), pure oxygen (industrial oxygen), oxygen-enriched air or air may be used, but pure oxygen is preferable when melting the cold iron source (94) in the electric furnace (90).

[051] The flow rate of the combustion support gas (30) is preferably 300 NL / min or more. The combustion support gas pipe (3) can be fixed in connection with the gaseous fuel pipe (4). An internal and external diameter of the combustion support gas pipe (3) are not limited to any specific value, but from the perspective of ensuring the flow rate of the combustion support gas (30) and reducing costs, when the combustion support gas pipe (3) surrounds the gaseous fuel pipe (4), the internal diameter is preferably 150 mm or less and may be greater than 50 mm.

[052] The combustion support gas pipe (3) may have a tubular shape and the material properties must be appropriately selected in relation to the ambient temperature and the resistance of the installation site. From a cost perspective, carbon steel, stainless steel or similar materials are preferable.

[053] When the lens (7) is a relay lens, the combustion support gas tube (3), the gaseous fuel tube (4), the outer tube (5), the inner tube (6) and the lens (7) are preferably arranged coaxially. (COOLING PIPE)

[054] The cooling tube (2) surrounds the gaseous fuel tube (4) and the combustion support gas tube (3) and is disposed in the most Petition 870260059225, dated 06 / 17 / 2026, page 25 / 84 16 / 31 external to the burner body. For example, when the burner body coolant (20) flows through a coolant supply port (21) and a coolant outlet (22) arranged as illustrated by the cooling tube (2) in Figure 1, the burner body can be used in high temperature environments, such as the electric furnace (90), while cooling the burner body. For example, even when producing cast iron (96) from the cold iron source (94) in the electric furnace (90), the burner body coolant (20) can be discharged outside the furnace through the coolant outlet (22) and therefore, from the point of view of cooling efficiency, the burner body coolant (20) is preferably a liquid, and water is preferably used.

[055] When the burner (1) is used at high temperatures, icicle-like masses may form from a leading end of the cooling tube (2). Even in these cases, the flame of the burner (1) is able to melt icicle-like masses, maintaining a clean image field.

[056] The properties of the refrigeration tube material (2) must be selected appropriately in relation to the ambient temperature and the resistance of the installation site. From a cost perspective, carbon steel, stainless steel or similar are preferable. (ELECTRIC FURNACE)

[057] An electric furnace according to the present disclosure is an electric furnace for melting a cold iron source to produce cast iron and is provided with the burner with the imaging device as described above. When the electric furnace is provided with the burner with the imaging device set, the burner can be operated while visually checking the cold iron source at the cold point being melted by the burner. Consequently, the casting Petition 870260059225, dated 06 / 17 / 2026, page 26 / 84 Inadequate 17 / 31 pressure and excessive melting by the burner can be avoided, melting efficiency can be increased, and production costs can be reduced.

[058] Besides comprising the burner (1), the electric furnace (90) is not limited in any particular way, and a common electric furnace can be used. Figure 3 schematically illustrates the cold iron source (94) being melted in the melting chamber of the electric furnace (90) by the heat generated by an electrode (92) and the flame of the burner (1) to become molten iron (96). At a cold spot in the melting chamber that is relatively far from the electrode (92), the cold iron source (94) may not receive sufficient heat from the electrode (92) and may remain unmelted. The electric furnace is supplied with the burner set and therefore the burner can only be used when necessary, with good confirmation of the presence or absence of the unmelted cold iron source (94).

[059] The arrangement of the burner (1) is not limited to any particular position, provided that the cold iron source (94) at the cold point is in view, and the burner (1) is preferably installed through a furnace wall of the casting chamber, as illustrated in Figure 3. Such installation allows the front of the lens (7) to be positioned inside the furnace to clearly capture the cold iron source (94) in the furnace, while the imaging system (8) is positioned outside the furnace to protect the imaging system (8) from the intense heat and simplify maintenance. The angle and height at which the burner (1) is installed are appropriately adjusted so that the cold iron source (94) can be clearly captured.

[060] Furthermore, the burner (1) is preferably installed so that at least one oxygen blow lance (97) and one carbon material blow lance (98) are within a field of vision, both Petition 870260059225, dated 06 / 17 / 2026, p. 27 / 84 18 / 31 are described below, or more preferably, so that both are within the field of vision. When the burner (1) can also be used to visually check the oxygen blow lance (97) and / or the carbon material blow lance (98), the operating conditions of the oxygen blow lance (97) and / or the carbon material blow lance (98) can be controlled even more efficiently. For example, by confirming that the cold iron source (94) is sufficiently melted, a blowing amount from the oxygen blow lance (97) and / or the carbon material blow lance (98) can be reduced or stopped.In order for the burner (1) to also be used in capturing the oxygen blow lance (97) and / or the carbon material blow lance (98), the field of view of the burner (1) can be enlarged or a new burner with an imaging device can be installed to monitor the oxygen blow lance (97) and the carbon material blow lance (98). (METHOD FOR PRODUCING CAST IRON)

[061] The production method is a method for producing cast iron by casting from a cold iron source comprising controlling the operating conditions of the burner based on visual information obtained from the burner with the imaging device described above. The production method then produces the same effects as the electric furnace described above.

[062] The production method is not particularly limited in any way, normal processing can be followed, except that an electric furnace provided with the burner with the defined imaging device is used and the visual information from the burner with the imaging device is used. Figure 4 schematically illustrates cast iron (96) being produced using the electric furnace (90) provided with a plurality of burners (1). The cold iron source (94) is supplied to the casting chamber of Petition 870260059225, dated 06 / 17 / 2026, p. 28 / 84 19 / 31 electric furnace (90), and the heat generated by the electrode (92) melts the cold iron source (94) into molten iron (96). Preheating the cold iron source (94) before feeding the casting chamber can increase casting efficiency. During casting, carbon material as an auxiliary heat source can be further supplied from the carbon material blow lance (98), and oxygen for decarburization can be supplied from the oxygen blow lance (97). In addition, the cold iron source (94) that is present at the cold point and not melted is intensely melted using the burner (1) to efficiently produce molten iron (96). The molten iron (96) accumulated in the casting chamber can be poured from the furnace through any pouring port on a molten iron pouring side. The molten slag produced with the cast iron (96) can be discharged from the furnace from any tailings outlet on a slag tailings side.

[063] According to the present disclosure, the burner (1) can be operated based on visual information obtained from the burner (1), for example, during verification of the molten state of the cold iron source (94), and this can optimize the operating conditions of the burner (1) without hazardous operations. This is useful in cast iron production processes to increase production efficiency and reduce production costs.

[064] Specifically, for example, when visual information obtained from the burner (1) confirms that the cold iron source (94) is not melted, the burning rate of the burner (1) is preferably increased to accelerate melting. On the other hand, when visual information obtained from the burner (1) confirms that the cold iron source (94) at a cold point has already melted, the burning rate of the burner (1) is preferably reduced, or the burner (1) is extinguished, to control unnecessary energy consumption due to overheating and to inhibit oxidation. Petition 870260059225, dated 06 / 17 / 2026, p. 29 / 84 20 / 31 of iron.

[065] Conventional burners do not have the imaging device (8) and it was not possible in practice to verify the melting state of the cold iron source (94) during burner operation. Therefore, according to conventional technology, the burners were operated according to the operator's experience and there was a tendency to overuse the burners to avoid leaving an unmelted cold iron source. However, according to the present disclosure, the burner operating conditions can be controlled in a timely manner during visual verification of the melting state of a cold iron source, making it possible to optimize the burner operating conditions and handle the unmelted cold iron source (94) in a highly efficient manner.

[066] During cast iron production, molten iron (96) and molten slag can boil in the furnace and adhere to and deposit on the front surface of the burner lens (1), narrowing the field of view of an image obtained. When visual information obtained from the burner (1) confirms the presence of an adherent material on the front surface of the lens, the adherent material is preferably removed from the lens by injecting combustion support gas (30) from the combustion support gas tube (3) or, in addition, by injecting more gaseous fuel (40) from the gaseous fuel tube (4). For example, upon confirming that slag has adhered to or deposited on the front surface of the lens, initially only combustion support gas (30) is injected to oxidize the iron in the slag and generate heat of oxidation reaction, which can again melt and remove the adhered or deposited slag.When this does not remove the adhered or deposited slag, gaseous fuel (40) can be injected in addition to the combustion support gas (30), and the heat of combustion from the flame formed melts the slag even further to remove the adhered or deposited slag. In this way, the efficiency of. Petition 870260059225, dated 06 / 17 / 2026, page 30 / 84 21 / 31 casting according to the burner can be optimized while constantly monitoring the cold iron source (94).

[067] Furthermore, the burner (1) is more preferably used to check at least one, and more preferably both, the oxygen blow lance (97) and the carbon material blow lance (98), and when the cold iron source (94) that is not melted is identified, to increase the amount of blow from the oxygen blow lance (97) and / or the carbon material blow lance (98) to further promote melting. On the other hand, upon confirmation that the cold iron source (94) is already melted using the burner (1), the amount of blow from the oxygen blow lance (97) and / or the carbon material blow lance (98) is more preferably reduced or stopped. EXAMPLES

[068] The following describes specific examples of the present revelation. The following examples indicate only preferred examples, and the present revelation is in no way limited to the examples described. Furthermore, the following examples may be modified without departing from the scope and spirit of the present revelation, and such modifications are also included within the technical scope of the present revelation. EXAMPLE 1

[069] The electric furnace (90) with the burner (1) as illustrated in Figure 1 and installed as schematically illustrated in Figure 3 and Figure 4 was used to melt the cold iron source (94) to produce cast iron (96). The electric furnace (90) was a direct current type with a furnace diameter of about 6.3 m, a furnace height of 4.1 m and a steel production of about 120 tons, with the oxygen blow lance (97) and the carbon material blow lance (98) being water-cooled and installed in the furnace from above and the electrode (92) installed Petition 870260059225, dated 06 / 17 / 2026, page 31 / 84 22 / 31 individually in a horizontal center of the furnace. A plurality of burners (1) (#1, #2, #3) was installed through the furnace wall in a total of three locations, divided approximately evenly around the perimeter of the furnace body (see Figure 3).

[070] The basic operating conditions of the electric furnace were indicated below.

[071] Weight of cold iron source supply per load: approx. 130 tons.

[072] Weight of cold iron source supply each time: approx. 65 tons.

[073] Number of times the cold iron source was supplied per load: 2 times.

[074] Type of cold iron source: Heavy H2 (from “Uniform Standards of Ferrous Scraps” by The Japan Ferrous Raw Materials Association).

[075] Steel output per load: approx. 120 tons.

[076] Target leakage temperature: 1580 °C.

[077] Target carbon leakage concentration: 0.060%.

[078] Supply weight of coke lumps (secondary raw material): 1000 kg.

[079] Weight of lime supply (secondary raw material): 500 kg.

[080] Oxygen blast flow rate (pure oxygen): 0 Nm3 / ha 5000 Nm3 / h.

[081] Carbon material blowing rate (coke breeze): 0 kg / min to 100 kg / min, carbon material carrier gas flow rate (air): approx. 350 Nm3 / h.

[082] Gaseous fuel (LNG) flow rate per burner (1): 0 Nm3 / ha 350 Nm3 / h.

[083] Flow rate of combustion support gas (pure oxygen) per Petition 870260059225, dated 06 / 17 / 2026, page 32 / 84 23 / 31 burner (1): 0 Nm3 / ha 770 Nm3 / h.

[084] Lens coolant flow rate (air) per burner (1): 8 Nm3 / h.

[085] The cold iron source (94) was supplied from the bucket to the electric furnace (90) on two separate occasions, before and during operation. Before operation, as auxiliary fuel, coke lumps and lime rejects were supplied to the electric furnace (90) from an auxiliary fuel supply chute (not shown).

[086] The cold iron source (94) was melted while pure oxygen and coke breeze were supplied from the oxygen blow lance (97) and the carbon material blow lance (98), respectively.

[087] Here, during the casting process, the burner (1) was used to observe the cold iron source (94) at three distant cold points from the electrode (92), and the operating conditions of the burner (1) were altered accordingly based on the visual information obtained. Specifically, when the unmelted cold iron source (94) was identified, the gaseous fuel flow rate (40) and / or the combustion support gas flow rate (30) of the burner (1) that was used to generate images of the cold iron source (94) were increased within the above ranges until it was confirmed that the entire cold iron source (94) was melted. On the other hand, when it was confirmed that all the cold iron source (94) had melted to become the cast iron (96), the flow rate of the gaseous fuel (40) and / or the flow rate of the combustion support gas (30) of the burner (1) that was used to rework the cast iron (96) were reduced within the above ranges, or the burner (1) was extinguished.

[088] Furthermore, when visual information from the burner (1) confirmed that material had adhered to the lens (7), the flow rate of the combustion support gas (30) and, if necessary, the flow rate of the gaseous fuel (40) from the burner (1) that was used to depict the adhering material was increased. Petition 870260059225, dated 06 / 17 / 2026, page 33 / 84 24 / 31 within the above lanes until confirmation was obtained that the adhering material had been removed. This ensured a clear field of vision throughout the operation.

[089] The casting process for a charge was completed when 120 tons of molten iron (96) were produced and the molten iron (96) was removed from a pouring outlet to a ladle outside the furnace. This was repeated for 20 charges. The target temperature of the molten iron (96) when poured was approximately 1580 °C and the target carbon concentration of the molten iron (96) when poured was 0.060% by mass and, according to Example 1, the average temperature of the molten iron when poured was 1600 °C and the average carbon concentration was 0.056% by mass.

[090] Average values ​​for production time, electrical energy consumption rate, oxygen consumption rate, coke consumption rate, and gaseous fuel consumption rate and combustion support gas consumption rate per burner (1) were calculated. The results are listed in Table 1. Here, each consumption rate can be calculated as an amount used per ton of cast pig iron. EXAMPLE 2

[091] According to Example 2, the cast iron (96) was produced for 20 charges under the same conditions as Example 1, except for the following points. According to Example 2, the cold iron source (94) near the oxygen blow lance (97) and the carbon material blow lance (98) was also observed through the burner (1) during the casting process, and the operating conditions of the oxygen blow lance (97) and the carbon material blow lance (98) were also altered accordingly based on the visual information obtained. Specifically, when the unmelted cold iron source (94) was identified, the oxygen blow lance flow rate (97) and the flow rate Petition 870260059225, dated 06 / 17 / 2026, page 34 / 84 25 / 31 of the carbon material blow lance (98) were increased within the above ranges. Conversely, when it was confirmed that all the cold iron source (94) had been melted into cast iron (96), the oxygen blow lance (97) blow flow rate and the carbon material blow lance (98) blow rate were reduced within the above ranges, or stopped.

[092] The target temperature of the cast iron (96) when poured was approximately 1580 °C and the target carbon concentration of the cast iron (96) when poured was 0.060% by mass and, according to Example 2, the average temperature of the cast iron when poured was 1590 °C and the average carbon concentration was 0.058% by mass.

[093] Average values ​​for production time, electrical energy consumption rate, oxygen consumption rate, coke consumption rate, gaseous fuel consumption rate and combustion support gas consumption rate per burner (1) were calculated. The results are listed in Table 1. COMPARATIVE EXAMPLE

[094] The operating conditions of the burner (1) were controlled based on the operator's experience without using the burner (1) imaging device (8) and without visual confirmation of the casting state of the cold iron source (94). Otherwise, the cast iron (96) was produced for 20 loads under the same conditions as those of Example 1 and Example 2.

[095] The target temperature of the cast iron (96) when poured was approximately 1,580 °C and the target carbon concentration of the cast iron (96) when poured was 0.060% by mass and, according to the comparative example, the average temperature of the cast iron when poured was 1640 °C and the average carbon concentration was 0.054% by mass. Petition 870260059225, dated 06 / 17 / 2026, p. 35 / 84 26 / 31

[096] Average values ​​for production time, electrical energy consumption rate, oxygen consumption rate, coke consumption rate, gaseous fuel consumption rate and combustion support gas consumption rate per burner (1) were calculated. The results are listed in Table 1. Petition 870260059225, dated 06 / 17 / 2026, p. 36 / 84 27 / 31 [Table 1] Burner Average consumption of combustion support gas (Nm3 / t) CM O) o O) 00 oo Average consumption of gaseous fuel (Nm3 / t) CM o Electric furnace Average consumption of carbon material (kg / t) CM o oo (D Average oxygen consumption (Nm3 / t) 28.4 27.5 27.0 Average electrical energy consumption (kWh / t) 385.3 CO CO 366.0 Average production time (min / load) 62.5 60.6 59.4 Casting process Burner operating conditions controlled based on empirical judgment without the use of an imaging device Burner operating conditions controlled based on visual information from the imaging device Burner, oxygen blow lance and carbon material blow lance operating conditions controlled based on visual information from the imaging device Comparative example o E ω X LU Example 2 In the units in the table, “ / t” means per ton of cast iron. Petition 870260059225, dated 06 / 17 / 2026, page 37 / 84 28 / 31

[097] As can be seen from Table 1, compared with the comparison example, Examples 1 and 2 reduced production time and electrical energy consumption rate. Oxygen consumption rate, coke consumption rate, burner gaseous fuel consumption rate, and burner combustion support gas consumption rate were also reduced according to Examples 1 and 2. This is because the furnaces of Examples 1 and 2 were operable during visual verification of the internal furnace conditions, in particular allowing for quick verification and determination of the smelting state of cold iron sources at cold spots to immediately control burner operating conditions to effectively suppress unnecessary burner blowdown.

[098] Furthermore, the rapid confirmation of the smelting of cold iron sources also made it possible to supply additional cold iron sources at the appropriate time for continuous operation. The additional supply of cold iron sources affects production time and the rate of electricity consumption. When the time for supplying additional cold iron source is too early, new cold iron sources may be supplied over semi-melted or unmelted cold iron sources in the furnace, causing them to melt and form large clumps. This inhibits the smelting progress, resulting in worse production time and electricity consumption. When the time for supplying additional cold iron source is too late, energy is wasted and the molten iron is overheated. This again results in worse production time and electricity consumption rate.

[099] In the case of Examples 1 and 2, the burner, the lens and the imaging device are integrated into a single unit and the heat from the burner successfully prevented the adhesion or deposition of a material, such as slag, Petition 870260059225, dated 06 / 17 / 2026, page 38 / 84 29 / 31 to cover the front of the lenses. Furthermore, even when material such as slag adhered to or was deposited on the front of the lens, the condition of the burner lens front could always be checked by means of the imaging device, and therefore the burner could be operated while clearing blockages in the field of view caused by the adhesion or deposition of material such as slag, by the immediate injection of combustion support gas or gaseous fuel as needed. In this way, the state of the cold iron source could be constantly monitored in the furnace during operation.

[100] Furthermore, according to Example 2, the operating conditions of the oxygen blow lance (97) and the carbon material blow lance (98) were also adjusted based on visual information through the burner, which further improved casting efficiency. Specifically, when oxygen and carbon material are blown in, the combustion of the carbon material generates carbon monoxide gas, which promotes the so-called “slag formation”, in which molten slag bubbles. Where slag formation has an effect of reducing the radiant heat of an arc and improving the casting efficiency of the cold iron source, the state of the molten iron and molten slag, depicted through the burner, allows for the prevention of excessive oxygen and carbon material blowing, and slag formation can be successfully generated and maintained.This resulted in further improvements in foundry efficiency and a further reduction in electricity consumption and production time. INDUSTRIAL APPLICABILITY

[101] According to the present disclosure, when heating an object with the burner, the interior of the furnace where the object is heated can be clearly observed, reducing production costs in the furnace. LIST OF REFERENCE SIGNS Petition 870260059225, dated 06 / 17 / 2026, page 39 / 84 30 / 31 1 Burner (with imaging device) 2 Cooling tube 20 Burner body coolant 21 Coolant supply port 22 Coolant outlet 3 Combustion support gas tube 30 Combustion support gas 31 Combustion support gas supply port 32 Combustion support gas injection port 4 Gaseous fuel tube 40 Gaseous fuel 41 Gaseous fuel supply port 42 Gas fuel injection port 5 Outer tube 6 Inner tube 7 Lens 70 Lens coolant 71 Coolant supply port 72 Coolant outlet 8 Imaging device 80 Imaging device coolant 81 Coolant supply port 82 Coolant outlet 83 Casing 90 Electric furnace 92 Electrode 94 Cold iron source 96 Cast iron Petition 870260059225, dated 06 / 17 / 2026, page 40 / 84 31 / 31 Oxygen breath lance Blow lance made of carbon fiber Petition 870260059225, dated 06 / 17 / 2026, p. 41 / 84

Claims

1 / 3 CLAIMS 1. An operable electric furnace (90) for melting a cold iron source (94) to produce cast iron (96), wherein the electric furnace (90) is provided with a burner (1) with an imaging device (8), the burner (1) burning gaseous fuel to form a flame, and wherein the burner (1) comprises: a lens; the imaging device (8) disposed behind the lens, wherein one side of the lens towards an object to be pictured is defined as front and an opposite side of the lens from the object to be pictured along an optical axis of the lens is defined as rear; and a multi-tube structure comprising: an inner tube (6) encircling the lens; an outer tube (5) encircling the inner tube (6),is larger in diameter than the inner tube (6) and is separated from the inner tube (6) by a lens coolant passage; the electric furnace (90) CHARACTERIZED in that the multi-tube structure further comprises: a gaseous fuel tube (4) radially disposed outward from the outer tube (5) and operable to inject gaseous fuel in a forward direction from the lens; a combustion support gas tube (3) radially disposed outward from the outer tube (5) and operable to inject combustion support gas (30) in a forward direction from the lens; and a cooling tube (2) disposed more externally in the multi-tube structure surrounding the gaseous fuel tube (4) and the combustion support gas tube (3), wherein Petition 870260059225, dated 17 / 06 / 2026, page. 42 / 84 2 / 3 the gaseous fuel tube (4) is larger in diameter than the outer tube (5), surrounds the outer tube (5) and is separated from the outer tube (5) by a gaseous fuel passage,The combustion support gas tube (3) is larger in diameter than the gaseous fuel tube (4), surrounds the gaseous fuel tube (4) and is separated from the gaseous fuel tube (4) by a combustion support gas passage; the cooling tube (2) is larger in diameter than the combustion support gas tube (3), surrounds the combustion support gas tube (3) and is separated from the combustion support gas tube (3) by a burner body coolant passage; and the inner tube (6), the outer tube (5), the gaseous fuel tube (4), the combustion support gas tube (3) and the cooling tube (2) are arranged coaxially.

2. Electric furnace (90), according to claim 1, CHARACTERIZED in that tube openings in an axial direction of the tube are arranged in order of inner tube (6), outer tube (5) and gaseous fuel tube (4) along the frontal direction of the lens.

3. Method for producing cast iron (96) by casting from a cold iron source (94) using the electric furnace (90), as defined in claim 1 or 2, CHARACTERIZED in that the operating conditions of the burner (1) are controlled based on visual information obtained from the burner (1).

4. Method for producing cast iron (96), according to claim 3, CHARACTERIZED in that when visual information obtained from the burner (1) confirms the presence of an adhering material on a front surface of the lens, the combustion support gas (30) is injected from the combustion support gas tube (3) or the combustion support gas (30) is injected from the combustion support gas tube (3) and the gaseous fuel is injected from the gaseous fuel tube (4), in order to remove the adhering material from the lens.

Images