Cooling device for bottom electrode of direct-current submerged arc furnace and direct-current submerged arc furnace

Abstract

The utility model relates to the technical field of submerged arc furnaces, in particular to a bottom electrode cooling device of a direct-current submerged arc furnace and the direct-current submerged arc furnace, and the bottom electrode cooling device of the direct-current submerged arc furnace comprises a first pipeline and a second pipeline, the first opening is used for installing a first pipeline, the inner side wall of the first opening is in sealed connection with the outer side wall of the first pipeline, the second opening is used for installing a second pipeline, the inner side wall of the second opening is in sealed connection with the outer side wall of the second pipeline, and the first pipeline and the second pipeline both communicate with the heat exchange cavity; the first end of the first pipeline and the first end of the second pipeline are located on the two opposite sides of the heat exchange cavity correspondingly, the first end of the first pipeline is close to the end face of the end of the electrode, and a cooling medium enters the heat exchange cavity from the first end of the first pipeline to flow circularly and then flows out of the heat exchange cavity through the first end of the second pipeline. According to the utility model, the safety and the efficiency of cooling the end part of the electrode are improved.

Description

Technical Field

[0001] This utility model relates to the field of electric arc furnace technology, specifically to a cooling device for the bottom electrode of a DC electric arc furnace and the DC electric arc furnace itself. Background Technology

[0002] In modern industrial processes, DC submerged arc furnaces have become crucial equipment in metallurgy, chemical engineering, and other fields due to their unique advantages. Using a DC electric arc as its core heat source, it surpasses traditional AC submerged arc furnaces in both energy efficiency and operational stability. The bottom electrodes of DC submerged arc furnaces are typically made of graphite. Because current needs to be conducted out of the furnace body, the graphite electrodes must extend to the outside of the furnace. However, the high thermal conductivity of graphite electrodes poses a risk of oxidation; therefore, effective cooling is a critical factor in ensuring the normal operation of the equipment.

[0003] Currently, there are two common methods for cooling graphite electrodes: air cooling and water cooling. However, neither can meet the ideal cooling requirements. Air cooling suffers from insufficient thermal conductivity due to the inherent limitations of air, making it difficult to quickly dissipate the large amount of heat generated by the graphite electrode during operation, resulting in unsatisfactory cooling performance. While water cooling theoretically offers stronger heat dissipation capabilities, some solutions employ multiple layers of water-cooling pipes nested around the graphite electrode. This not only increases the manufacturing difficulty and production cost but also introduces safety hazards. If molten iron flowing downwards through a DC submerged arc furnace comes into contact with the water-cooling pipes, a vaporization reaction can occur, easily triggering an explosion. This seriously threatens equipment and personnel safety and compromises the reliability of the cooling process. Utility Model Content

[0004] To address the technical problems of low cooling efficiency and safety of graphite electrodes in DC submerged arc furnaces, the present invention aims to provide a bottom electrode cooling device and a DC submerged arc furnace. The specific technical solution adopted is as follows:

[0005] In a first aspect, this utility model provides a bottom electrode cooling device for a DC submerged arc furnace. The DC submerged arc furnace includes a bottom electrode with a heat exchange cavity inside. The portion of the bottom electrode with the heat exchange cavity serves as the electrode end and is not located within the DC submerged arc furnace. The electrode end has a first opening and a second opening. The cooling device for the bottom electrode includes a first pipe and a second pipe. The first opening is used to install the first pipe, and the inner wall of the first opening is sealed to the outer wall of the first pipe. The second opening is used to install the second pipe, and the inner wall of the second opening is sealed to the outer wall of the second pipe. Both the first pipe and the second pipe are connected to the heat exchange cavity. The first end of the first pipe and the first end of the second pipe are located on opposite sides of the heat exchange cavity. The first end of the first pipe is close to the end face of the electrode end. The cooling medium enters the heat exchange cavity from the first end of the first pipe, circulates, and then flows out of the heat exchange cavity through the first end of the second pipe. The distance from the first end of the first pipe to the center of the DC submerged arc furnace is less than the distance from the first end of the second pipe to the center of the DC submerged arc furnace.

[0006] Optionally, the electrode end includes an end face and a seal. The heat exchange chamber, the first opening, and the second opening are located near the bottom electrode of the DC submerged arc furnace, exposed on the end face of the electrode end outside the DC submerged arc furnace. The end face has an opening with the same diameter as the heat exchange chamber. The seal is sealed to the opening. The heat exchange chamber extends axially from the opening toward the interior of the electrode end. The first opening and the second opening are both provided through the seal. The first pipe communicates with the heat exchange chamber through the first opening, and the second pipe communicates with the heat exchange chamber through the second opening.

[0007] Optionally, the cooling device further includes a first tensioning member and a first sealing member; the first tensioning member is disposed inside the heat exchange chamber and fixed to the side wall of the electrode end, and the sealing member is provided with a third opening along the axial direction. The sealing member is fixed to the end face by the first sealing member and the first tensioning member cooperating with each other. The first sealing member passes through the third opening and cooperates with the first tensioning member. The first sealing member is fixed after passing through the third opening so that the sealing member is relatively fixed.

[0008] Optionally, the cooling device further includes: a first support frame, a first heat-conducting element, and a first heat-insulating element. The first support frame is disposed inside the heat exchange cavity and is fixedly connected to the inner wall of the electrode end. The portion of the second pipe located inside the heat exchange cavity passes through the first support frame to support the portion of the second pipe located inside the heat exchange cavity, thereby preventing the portion of the second pipe located inside the heat exchange cavity from bending or shaking. The first support frame is disposed on one side of the second end of the second pipe for supporting the second pipe. The first heat-conducting element is disposed between the contact surface of the first support frame and the inner wall of the electrode end and is tightly connected to the first support frame and the inner wall of the electrode end to conduct heat from the electrode end to the first support frame and exchange heat with the cooling medium. The first heat-insulating element is disposed between the contact surface of the first support frame and the outer wall of the second pipe and is tightly connected to the outer walls of the first support frame and the second pipe to prevent heat from the cooling medium in the second pipe from being conducted into the interior of the heat exchange cavity.

[0009] Optionally, the electrode end includes an end face and a seal. The end face has an opening with the same diameter as the heat exchange cavity. The seal is sealed to the opening. The heat exchange cavity extends axially from the opening toward the interior of the electrode end. The first opening and the second opening are both located on the sidewall of the electrode end. The first pipe communicates with the heat exchange cavity through the first opening, and the second pipe communicates with the heat exchange cavity through the second opening. The portion of the first pipe located in the heat exchange cavity and the portion of the second pipe located in the heat exchange cavity are perpendicular to each other.

[0010] Optionally, the cooling device further includes a second tensioning member and a second sealing member; one end of the second tensioning member is fixedly connected to the portion of the first pipe located in the heat exchange chamber, and the sealing member is also provided with a fourth opening along the axial direction. The sealing member is fixed to the end face by the cooperation of the second sealing member and the second tensioning member. The second sealing member passes through the fourth opening and cooperates with the second tensioning member. The other end of the second sealing member passes through the fourth opening and is fixed, so that the sealing member and the portion of the first pipe located in the heat exchange chamber are relatively fixed.

[0011] Optionally, the pipe wall of the portion of the first pipe extending into the heat exchange chamber is also provided with multiple water outlet holes, and the inner wall of the heat exchange chamber is coated with an insulating and thermally conductive coating.

[0012] Optionally, the cooling device further includes a second support frame disposed inside the heat exchange chamber; the second pipe includes a first sub-pipe and a second sub-pipe, the first sub-pipe being sealed to a second opening, the second sub-pipe being sealed to the first sub-pipe via a connector, and the first sub-pipe extending radially along the heat exchange chamber, and the second sub-pipe extending axially along the heat exchange chamber; the first sub-pipe is arranged to extend radially along the heat exchange chamber, and the second end of the second sub-pipe is close to the bottom of the electrode end; the second support frame is disposed on one side of the second end of the second sub-pipe, and the second sub-pipe passes through the second support frame to support the second sub-pipe, so as to prevent the second sub-pipe from bending and shaking; the portion of the second sub-pipe located inside the heat exchange chamber points towards the center of the furnace, and a buffer hole is provided on the inner wall of the bottom electrode corresponding to the outlet of the first end of the portion of the first pipe located inside the heat exchange chamber, the diameter of the buffer hole being larger than the outer diameter of the first pipe, and the first end of the portion of the first pipe located inside the heat exchange chamber being located in the buffer hole, so as to utilize the impact force of the cooling medium in the buffer hole to make the cooling medium entering the heat exchange chamber flow stably and directionally towards the drain outlet corresponding to the second end of the second sub-pipe.

[0013] Optionally, the cooling device further includes: a second heat-conducting element and a second heat-insulating element; the second heat-conducting element is disposed on the bottom surface of the electrode end to conduct the heat at the bottom of the electrode end to the interior of the heat exchange cavity for heat exchange with the cooling medium; the second heat-insulating element is disposed on the outer wall of the second pipe to prevent the cooling medium in the second pipe from exchanging heat with the cooling medium inside the heat exchange cavity.

[0014] Secondly, this utility model provides a DC submerged arc furnace, including a bottom electrode and a cooling device for the bottom electrode of the DC submerged arc furnace as mentioned in the first aspect. The bottom electrode has a heat exchange cavity inside, and the part of the bottom electrode with the heat exchange cavity serves as the electrode end and is not inside the DC submerged arc furnace. The electrode end is provided with a first opening and a second opening. The cooling device for the bottom electrode includes a first pipe and a second pipe. The first opening is used to install the first pipe, and the inner sidewall of the first opening is sealed to the outer sidewall of the first pipe. The second opening is used to install the second pipe, and the inner sidewall of the second opening is sealed to the outer sidewall of the second pipe. Both the first pipe and the second pipe are in communication with the heat exchange cavity, and the first end of the first pipe and the first end of the second pipe are respectively located on opposite sides of the heat exchange cavity. The first end of the first pipe is close to the end face of the electrode end. The cooling medium enters the heat exchange cavity from the first end of the first pipe, circulates, and then flows out of the heat exchange cavity through the first end of the second pipe. The distance from the first end of the first pipe to the center of the DC submerged arc furnace is less than the distance from the first end of the second pipe to the center of the DC submerged arc furnace.

[0015] In a cooling device for a DC submerged arc furnace disclosed in this utility model embodiment, the DC submerged arc furnace includes a bottom electrode with a heat exchange cavity inside. The portion of the bottom electrode with the heat exchange cavity serves as the electrode end and is not inside the DC submerged arc furnace. The electrode end is provided with a first opening and a second opening. The cooling device for the bottom electrode includes a first pipe and a second pipe. The first opening is used to install the first pipe, and the inner sidewall of the first opening is sealed to the outer sidewall of the first pipe. The second opening is used to install the second pipe, and the inner sidewall of the second opening is sealed to the outer sidewall of the second pipe. Both the first pipe and the second pipe are in communication with the heat exchange cavity. The first end of the first pipe and the first end of the second pipe are located on opposite sides of the heat exchange cavity. The first end of the first pipe is close to the end face of the electrode end. The cooling medium enters the heat exchange cavity from the first end of the first pipe, circulates, and then flows out of the heat exchange cavity through the first end of the second pipe. The distance from the first end of the first pipe to the center of the DC submerged arc furnace is less than the distance from the first end of the second pipe to the center of the DC submerged arc furnace.

[0016] Thus, in this embodiment of the invention, a heat exchange cavity is formed inside the electrode end of the bottom electrode, which is not located within the heat exchange cavity. The cooling medium provided by the cooling device is then introduced into the heat exchange cavity through the first pipe to cool the electrode end. The cooling medium can directly contact the interior of the electrode end, thereby quickly removing the heat generated at the electrode end, resulting in a better cooling effect and effectively improving cooling efficiency. This ensures stable operation of the bottom electrode in high-temperature environments and extends the electrode's service life. Furthermore, because the heat exchange cavity is located inside the electrode end and not within the DC submerged arc furnace, the problem of molten iron penetrating downwards in the DC submerged arc furnace is avoided, improving the safety of cooling the electrode end. In addition, the distance from the first end of the first pipe to the center of the DC submerged arc furnace is less than the distance from the first end of the second pipe to the center of the DC submerged arc furnace. The cooling medium can gradually flow from the end face of the electrode end to the bottom of the electrode end, progressively exchanging heat from the end face to the bottom of the electrode end. This avoids direct contact and vaporization between the cooling medium and the bottom of the electrode end, further improving cooling safety. Attached Figure Description

[0017] To more clearly illustrate the technical solutions and advantages in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a partial structural schematic diagram of the first DC submerged arc furnace disclosed in the embodiments of this utility model.

[0019] Figure 2This is a schematic cross-sectional view of a partial structure of the first DC submerged arc furnace disclosed in this utility model embodiment.

[0020] Figure 3 This is a schematic diagram of the external structure of a partial structure of the first DC submerged arc furnace disclosed in this utility model embodiment.

[0021] Figure 4 This is a partial structural schematic diagram of the second type of DC submerged arc furnace disclosed in this utility model embodiment.

[0022] Figure 5 This is a cross-sectional schematic diagram of a partial structure of the second type of DC submerged arc furnace disclosed in this utility model embodiment.

[0023] Figure 6 This is a schematic diagram of the external structure of a second type of DC submerged arc furnace disclosed in this utility model embodiment. Detailed Implementation

[0024] To further illustrate the technical means and effects adopted by this utility model to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a bottom electrode cooling device and a DC submerged arc furnace according to this utility model. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0026] The following description, in conjunction with the accompanying drawings, details the bottom electrode cooling device and specific scheme of the DC submerged arc furnace provided by this utility model.

[0027] like Figures 1 to 3As shown in the present invention, the bottom electrode cooling device of the DC submerged arc furnace disclosed in this embodiment includes: the DC submerged arc furnace includes a bottom electrode 101, the bottom electrode 101 has a heat exchange chamber 102 inside, the part of the bottom electrode 101 with the heat exchange chamber 102 serves as the electrode end and is not inside the DC submerged arc furnace, the electrode end is provided with a first opening 103 and a second opening 104, the bottom electrode cooling device includes: a first pipe 105 and a second pipe 106; the first opening 103 is used to install the first pipe 105 and the inner sidewall of the first opening 103 is sealed to the outer sidewall of the first pipe 105, the second opening 104 is used to install the second pipe 106 and the second opening 105 is sealed to the outer sidewall of the first pipe 105, and the second opening 104 is used to install the second pipe 106. The inner wall of the hole 104 is sealed to the outer wall of the second pipe 106. Both the first pipe 105 and the second pipe 106 are in communication with the heat exchange chamber 102. The first end of the first pipe 105 and the first end of the second pipe 106 are located on opposite sides of the heat exchange chamber 102. The first end of the first pipe 105 is close to the end face of the electrode end. The cooling medium enters the heat exchange chamber 102 from the first end of the first pipe 105 and flows out of the heat exchange chamber 102 through the first end of the second pipe 106. The distance from the first end of the first pipe 105 to the center of the DC electric arc furnace is less than the distance from the first end of the second pipe 106 to the center of the DC electric arc furnace.

[0028] Specifically, in this embodiment of the invention, the heat exchange cavity 102 can be configured as a spiral tube, honeycomb, or parallel flow channel structure. In this embodiment, the heat exchange cavity 102 is formed from the end face of the electrode end along the axial direction of the bottom electrode 101. To prevent corrosion of the electrode end by the cooling medium, the inner wall of the heat exchange cavity 102 is coated with a high thermal conductivity and insulating coating, such as a coating made of graphene / boron nitride composite material or an inorganic insulating and thermally conductive material. This insulating and thermally conductive coating prevents the cooling medium from directly contacting the bottom electrode through which DC current is applied, avoiding the risk of short circuits, leakage, or electrical breakdown caused by corrosion of the bottom electrode by the cooling medium. This further improves the cooling safety and reliability of the bottom electrode, ensuring the safe operation of the DC submerged arc furnace. Furthermore, this insulating and thermally conductive coating can quickly transfer heat from the surface of the bottom electrode to the cooling medium, reducing thermal resistance and improving heat dissipation efficiency, thereby further improving the cooling efficiency of the bottom electrode.

[0029] Furthermore, the first pipe 105 can be an inlet pipe, and the second pipe 106 can be an outlet pipe.

[0030] Furthermore, the portion of the bottom electrode 101 with the heat exchange chamber 102 serves as the electrode end and is not inside the DC submerged arc furnace; that is, the electrode end is the portion exposed outside the DC submerged arc furnace.

[0031] Furthermore, the temperature is highest at the bottom of the electrode tip, gradually decreasing towards the end face. If the cooling medium comes into contact with the bottom of the electrode tip immediately, it may vaporize, making it difficult to cool the bottom electrode and resulting in low cooling efficiency. In addition, water vapor occupies the heat exchange cavity space, preventing the cooling medium from completely filling the cavity and reducing the actual volume of liquid participating in heat exchange, further weakening the overall cooling capacity. This could lead to electrode temperature runaway and overheating failure, resulting in low cooling reliability and safety of the bottom electrode. Moreover, the volume of the cooling medium expands rapidly when it vaporizes. If the heat exchange cavity is a closed or semi-closed space, the vaporized gas cannot be discharged in time, causing a sudden increase in pressure inside the cavity. When the pressure exceeds the design limits of the heat exchange cavity, seals, or cavity, it may cause seal failure, pipe rupture, or joint leakage, resulting in cooling medium leakage, or even electric shock or equipment shutdown accidents, further reducing the cooling reliability and safety of the bottom electrode. Therefore, to avoid the problem of the cooling medium vaporizing upon initial contact with the bottom of the electrode tip, this embodiment of the invention employs a structure where the distance from the first end of the first pipe to the center of the DC submerged arc furnace is less than the distance from the first end of the second pipe to the center of the DC submerged arc furnace. This allows the cooling medium to flow gradually from the end of the electrode tip towards the bottom of the electrode tip after entering the heat exchange chamber from the first end of the first pipe. During this flow, the cooling medium sequentially exchanges heat with the inner wall of the heat exchange chamber, gradually cooling the electrode tip until it flows to the bottom of the electrode tip and is then discharged from the second pipe. Thus, by employing a structure where the distance from the first end of the first pipe to the center of the DC submerged arc furnace is less than the distance from the first end of the second pipe to the center of the DC submerged arc furnace, the incoming cooling medium can be prevented from vaporizing upon initial contact with the bottom of the electrode tip, improving cooling efficiency, cooling safety, and reliability.

[0032] Furthermore, as an optional embodiment of this utility model, the electrode end includes an end face 107 and a sealing member 108. The end face 107 is provided with an opening, and the diameter of the opening is the same as the diameter of the heat exchange chamber 102. The sealing member 108 is sealed to the opening. The heat exchange chamber 102 extends axially from the opening toward the interior of the electrode end. The first opening 103 and the second opening 104 are both opened on the side wall of the electrode end. The first pipe 105 communicates with the heat exchange chamber 102 through the first opening 103, and the second pipe 106 communicates with the heat exchange chamber 102 through the second opening 104. The portion of the first pipe 105 located in the heat exchange chamber 102 and the portion of the second pipe 106 located in the heat exchange chamber 102 are perpendicular to each other.

[0033] Specifically, in this embodiment of the invention, the first pipe 105 is inserted into the heat exchange chamber 102 through the first opening 103, and the second pipe 106 is inserted into the heat exchange chamber 102 through the second opening 104. The openings are sealed by a sealing element 108. In this embodiment of the invention, an opening is formed on the end face of the electrode end, and this opening can be sealed by a sealing element, including but not limited to silicone rubber sealing elements, ceramic-based sealing elements, metal-based sealing elements, and graphite-based sealing elements.

[0034] Furthermore, as an optional embodiment of this utility model, the cooling device further includes a second tensioning member 109 and a second sealing fixing member 1010; one end of the second tensioning member 109 is fixedly connected to the portion of the first pipe 105 located in the heat exchange chamber 102, and the sealing member 108 is also provided with a fourth opening along the axial direction. The sealing member 108 is fixed to the end face 107 by the second sealing fixing member 1010 and the second tensioning member 109 cooperating with each other. The second sealing fixing member 1010 passes through the fourth opening and cooperates with the second tensioning member 109. The other end of the second sealing fixing member 1010 passes through the fourth opening and is fixed, so that the sealing member 108 and the portion of the first pipe 105 located in the heat exchange chamber 102 are relatively fixed.

[0035] Specifically, the second tensioning member 109 can be integrated with the first pipe 105, or it can be a tensioning piece fixedly connected to the first pipe 105. The second tensioning member 109 has a tensioning hole that mates with the second sealing fastener 1010. The second sealing fastener 1010 passes through the fourth opening and is fixedly engaged with the tensioning hole on the second tensioning member 109. The second sealing fastener 1010 can be a bolt or a rubber ring. The bolt shank passes through the fourth opening, and the bolt head is located on the side of the fourth opening of the sealing member 108 outside the heat exchange chamber 102 and is sealed against the rubber ring. A fourth opening can be provided on the sealing member for installing the second sealing fastener 1010. One end of the second sealing fastener 1010 can pass through the fourth opening and be fixedly connected to the second tensioning member 109 on the first pipe. The other end of the second sealing fastener 1010 can be fixed to the other side of the fourth opening of the sealing member 108, thereby fixing the sealing member 108 to the first pipe and improving the reliability of the seal.

[0036] Furthermore, as an optional embodiment of this utility model, a plurality of water outlet holes are provided on the pipe wall of the portion of the first pipe 105 extending into the heat exchange chamber. Thus, in this embodiment of the utility model, multiple water outlet holes are provided on the pipe wall of the portion of the first pipe 105 extending into the heat exchange chamber, thereby accelerating the flow rate and speed of the heat exchange fluid entering the heat exchange chamber, further improving the cooling efficiency of the bottom electrode.

[0037] Furthermore, in this embodiment of the invention, the inner wall of the heat exchange cavity is coated with an insulating and thermally conductive coating. This insulating and thermally conductive coating can be a coating with high thermal conductivity and insulation, such as a ceramic matrix composite material, a polymer coating, a graphene / boron nitride composite material coating, or an inorganic insulating and thermally conductive material coating. The specific process for coating the heat exchange cavity with this insulating and thermally conductive coating is as follows: Before spraying, the inner wall of the heat exchange cavity needs to undergo strict surface treatment, including removing impurities such as oil, rust, and dust. Methods such as sandblasting and acid pickling are typically used to improve the adhesion between the coating and the substrate. A suitable insulating and thermally conductive coating material is selected based on the working environment and performance requirements of the heat exchange cavity. This embodiment of the invention does not limit the coating material. Common materials include ceramic matrix composite materials and polymer coatings, and different materials differ in terms of thermal conductivity, insulation performance, and high-temperature resistance. During the spraying process, parameters such as spraying temperature, pressure, and spray gun movement speed need to be precisely controlled to ensure that the uniformity and thickness of the coating meet the requirements. For example, plasma spraying technology typically requires controlling the plasma temperature to several thousand degrees Celsius and the spray gun movement speed to be between several centimeters and tens of centimeters per second. After spraying, post-processing techniques, such as heat treatment and grinding, are performed to further improve the performance and quality of the insulating and thermally conductive coating. For instance, heat treatment can eliminate internal stress in the coating, improving its density and stability.

[0038] Furthermore, the cooling device also includes a second support frame 1011, which is disposed inside the heat exchange chamber 102; the second pipe 106 includes a first sub-pipe and a second sub-pipe, the first sub-pipe being sealed to the second opening 104, and the second sub-pipe being sealed to the first sub-pipe via a connector, wherein the first sub-pipe extends radially along the heat exchange chamber 102, and the second sub-pipe extends axially along the heat exchange chamber 102; the first sub-pipe extends radially along the heat exchange chamber 102, and the second end of the second sub-pipe is close to the bottom of the electrode end; the second support frame 1011 is disposed on one side of the second end of the second sub-pipe, and the second sub-pipe... The channel passes through the second support frame 1011 to support the second sub-pipe and prevent it from bending and shaking. The portion of the second sub-pipe located inside the heat exchange chamber 102 points towards the center of the furnace. A buffer hole is provided on the inner wall of the bottom electrode corresponding to the outlet of the first end of the portion of the first pipe 105 located inside the heat exchange chamber 102. The diameter of the buffer hole is larger than the outer diameter of the first pipe 105, and the first end of the portion of the first pipe 105 located inside the heat exchange chamber 102 is located in the buffer hole. The impact force of the cooling medium in the buffer hole is used to make the cooling medium entering the heat exchange chamber 102 flow stably and directionally towards the drain outlet corresponding to the second end of the second sub-pipe.

[0039] Specifically, the second support frame 1011 is made of high-strength titanium alloy. This material not only possesses excellent strength and corrosion resistance but also has a low density, enabling it to provide reliable support for the second sub-pipe without adding excessive weight. Its structural design is a cross-shaped frame, with intersecting horizontal and vertical support beams forming a stable support network, further enhancing the overall rigidity of the support frame. The second support frame 1011 is precisely positioned and installed inside the heat exchange chamber 102. Its installation position has been verified through mechanical calculations and simulations to ensure optimal support for the second sub-pipe.

[0040] The second conduit 106 consists of a first sub-conduit and a second sub-conduit. This segmented design balances ease of installation and heat exchange efficiency. The first sub-conduit uses seamless stainless steel tubing, with its diameter precisely selected based on the flow and pressure requirements of the cooling medium. The wall thickness has been calculated for strength to ensure stable operation under high pressure. The first sub-conduit is sealed to the second opening 104. The second sub-conduit also uses high-quality stainless steel tubing and is sealed to the first sub-conduit via a specially designed flange. The flange is precision-machined and secured with gaskets and bolts to form a reliable sealing structure, ensuring stable delivery of the cooling medium within the conduit. The first sub-conduit extends radially along the heat exchange chamber 102, while the second sub-conduit extends axially along the heat exchange chamber 102. This perpendicular arrangement allows the cooling medium to form an efficient flow path within the chamber. The second end of the second sub-conduit is precisely positioned close to the bottom of the electrode tip, a design that effectively removes heat generated at the electrode tip, improving cooling efficiency.

[0041] The second support frame 1011 is located on one side of the second end of the second sub-pipe. A circular support hole, matching the outer diameter of the pipe, is provided where the second sub-pipe passes through the second support frame 1011. The inner wall of the support hole is polished and fitted with a wear-resistant PTFE bushing. This reduces friction between the pipe and the support frame, enhances the support effect, and effectively prevents the second sub-pipe from bending and shaking due to vibration, fluid impact, or other factors during long-term operation, ensuring stable delivery of the cooling medium. The portion of the second sub-pipe located within the heat exchange chamber 102 points towards the center of the furnace. This layout guides the cooling medium to concentrate on cooling key parts of the furnace, optimizing the heat exchange process.

[0042] The design of the portion of the first pipe 105 located within the heat exchange chamber 102, along with the buffer hole, further enhances the stability of the cooling medium flow. The first pipe 105 is made of copper tubing with excellent thermal conductivity, and its diameter is determined based on the flow rate requirements of the cooling system. A buffer hole is formed on the inner wall of the bottom electrode corresponding to the first end of the portion of the first pipe 105 located within the heat exchange chamber 102. The diameter of the buffer hole, calculated using fluid dynamics, is 2-3 times larger than the outer diameter of the first pipe 105. This size design ensures that the first end of the first pipe 105 can be smoothly placed in the buffer hole while providing sufficient buffer space for the cooling medium. The inner wall of the buffer hole is designed with a rounded transition. When the cooling medium flows out of the first pipe 105, the rounded inner wall effectively disperses the impact force of the fluid, adjusting the flow rate and direction of the cooling medium. This ensures a stable and directional flow towards the drain outlet corresponding to the second end of the second sub-pipe, avoiding turbulence caused by fluid impact and improving the overall efficiency and stability of the cooling system.

[0043] For further details, please see Figures 4 to 6 As an optional embodiment of this utility model, the electrode end includes an end face 107 and a sealing member 108. The heat exchange chamber 102, the first opening 103 and the second opening 104 are close to the bottom electrode of the DC submerged arc furnace. The end face 107 of the electrode end exposed outside the DC submerged arc furnace has an opening with the same diameter as the heat exchange chamber. The sealing member 108 is sealed to the opening. The heat exchange chamber 102 extends axially from the opening to the inside of the electrode end. The first opening 103 and the second opening 104 are both disposed through the sealing member 108. The first pipe 105 communicates with the heat exchange chamber through the first opening 103, and the second pipe 106 communicates with the heat exchange chamber 102 through the second opening 104.

[0044] Furthermore, as an optional embodiment of this utility model, the cooling device further includes a first tensioning member 1012 and a first sealing fixing member 1013; the first tensioning member 1012 is disposed inside the heat exchange chamber 102 and fixed on the side wall of the electrode end; the sealing member 108 is also provided with a third opening along the axial direction; the sealing member 108 is fixed to the end face by the first sealing fixing member 1013 cooperating with the first tensioning member; the first sealing fixing member 1013 passes through the third opening and cooperates with the first tensioning member 1012; the first sealing fixing member 1013 is fixed after passing through the third opening, so that the sealing member 108 is relatively fixed.

[0045] Specifically, the first sealing fastener 1013 can be a bolt and a rubber ring. The bolt shank passes through the third opening, and the bolt head is located on the side of the fourth opening of the sealing element 108 outside the heat exchange chamber 102 and is in contact with the rubber ring for sealing. A third opening can be made on the sealing element 108 for installing the first sealing fastener 1013. One end of the first sealing fastener 1013 can pass through the third opening and be fixedly connected to the first tensioning member 1012 on the first pipe. The other end of the first sealing fastener 1013 can be fixed on the other side of the third opening of the sealing element 108, thereby fixing the sealing element 108 to the electrode end and improving the reliability of the seal.

[0046] Furthermore, as an optional embodiment of this utility model, the cooling device further includes: a first support frame 1014, a first heat-conducting element (not shown in the figure), and a first heat-insulating element (not shown in the figure). The first support frame 1014 is disposed inside the heat exchange chamber 102 and is fixedly connected to the inner sidewall of the electrode end. The portion of the second pipe 106 located inside the heat exchange chamber 102 passes through the first support frame 1014, so as to use the first support frame 1014 to support the portion of the second pipe 106 located inside the heat exchange chamber 102, so as to prevent the portion of the second pipe 106 located inside the heat exchange chamber 102 from bending or shaking. The first support frame 1014 is disposed on the second pipe. One side of the second end of 106 is used to support the second pipe 106; the first heat-conducting element is disposed between the contact surface of the first support frame 1014 and the inner sidewall of the electrode end and is tightly connected to the first support frame 1014 and the inner sidewall of the electrode end to conduct the heat of the electrode end to the first support frame 1014 and exchange heat with the cooling medium; the first heat-insulating element is disposed between the contact surface of the first support frame 1014 and the outer sidewall of the second pipe 106 and is tightly connected to the outer sidewall of the first support frame 1014 and the second pipe 106 to prevent the heat of the cooling medium in the second pipe 106 from being conducted into the interior of the heat exchange chamber 102.

[0047] Specifically, in this embodiment, the first support frame 1014, the first heat-conducting element, and the first heat-insulating element play a crucial role in the heat management and structural stability of the heat exchange cavity 102. The first support frame 1014 is made of high-strength stainless steel, and its unique truss structure design ensures sufficient support strength while minimizing its own weight to reduce the load on the overall equipment. The dimensions of the first support frame 1014 are precisely calculated based on the diameter of the opening on the end face and the diameter of the heat exchange cavity. Its lateral span matches the internal width of the heat exchange cavity 102, and its longitudinal height is determined based on the installation position of the second pipe 106 within the heat exchange cavity 102, ensuring stable and reliable support for the second pipe 106.

[0048] Furthermore, the first support frame 1014 is precisely positioned inside the heat exchange cavity 102 and firmly fixed to the inner wall of the electrode end, forming a stable support structure. The portion of the second pipe 106 located inside the heat exchange cavity 102 passes through a pre-drilled circular through-hole in the first support frame 1014. The diameter of this through-hole is slightly larger than the outer diameter of the second pipe 106, ensuring smooth passage while also effectively preventing bending or shaking of the second pipe 106 within the heat exchange cavity 102 due to fluid pressure, vibration, or other factors, thanks to the limiting effect of the first support frame 1014. This ensures stable delivery of the cooling medium within the pipe. The first support frame 1014 is positioned on one side of the second end of the second pipe 106. In cases where the pipe is long, it acts as a stable anchor point, providing reliable lateral support to the second pipe 106 and maintaining its spatial accuracy.

[0049] The first heat-conducting component is made of graphite-based composite material with high thermal conductivity. Its surface undergoes special treatment, resulting in excellent flatness and fit. The first heat-conducting component is positioned between the contact surface of the first support frame 1014 and the inner wall of the electrode end. During installation, thermally conductive silicone grease is used to fill the tiny gaps, ensuring a tight connection between the component and the first support frame 1014 and the inner wall of the electrode end, forming a highly efficient heat conduction channel. During equipment operation, the electrode end generates a large amount of heat due to electrical energy conversion. This heat is rapidly conducted to the first support frame 1014 through the first heat-conducting component, and then heat is exchanged with the cooling medium flowing through the second pipe 106, carrying away the heat and effectively cooling the electrode end to ensure normal electrode operation.

[0050] The first thermal insulation component is made of a low thermal conductivity aerogel material. This material has a porous structure filled with numerous tiny air chambers, which greatly hinder heat transfer. The first thermal insulation component is positioned between the contact surfaces of the first support frame 1014 and the outer wall of the second pipe 106. Its shape is customized according to the contour of the contact area. During installation, it is firmly adhered using high-temperature resistant thermal insulation adhesive, ensuring a tight fit with the outer walls of the first support frame 1014 and the second pipe 106, forming a tight thermal barrier. In this way, the low-temperature heat carried by the cooling medium in the second pipe 106 is effectively blocked during flow, preventing it from being conducted into the heat exchange chamber 102, thus avoiding heat loss. It also prevents the high-temperature environment inside the heat exchange chamber from affecting the temperature of the cooling medium, ensuring the efficient operation of the cooling system.

[0051] Furthermore, the external cooling medium can be pressurized and extracted by a water pump and then enter the heat exchange chamber 102 through the first pipe 105.

[0052] Furthermore, the cooling device also includes: a second heat-conducting element and a second heat-insulating element; the second heat-conducting element is disposed on the bottom surface of the electrode end to conduct the heat at the bottom of the electrode end to the interior of the heat exchange cavity for heat exchange with the cooling medium; the second heat-insulating element is disposed on the outer wall of the second pipe to prevent the cooling medium in the second pipe from exchanging heat with the cooling medium inside the heat exchange cavity.

[0053] Specifically, a second heat-conducting element is installed on the bottom surface of the heat exchange cavity opposite to the end face of the electrode end. This measure significantly improves the heat transfer efficiency. The second heat-conducting element can be made of metal matrix composite material. This material uses metals such as aluminum and copper as the matrix, with uniformly dispersed reinforcing particles such as silicon carbide and alumina, and is formed by powder metallurgy or extrusion casting processes. It combines the good toughness and high thermal conductivity of metals with the high strength and wear resistance of reinforcing particles. Graphite heat-conducting elements utilize the layered crystal structure of natural flake graphite or artificial graphite, which has ultra-high thermal conductivity along the interlayer direction and strong chemical stability. Silicon carbide heat-conducting elements, with their covalently bonded crystal structure, have high hardness, high temperature resistance, and excellent thermal conductivity. When installing the second heat-conducting component, the bottom surface of the heat exchange chamber and the bottom surface of the electrode end are first precision ground to ensure that the surface roughness reaches Ra0.8 or less. Then, silver paste with high thermal conductivity is applied and hot-pressed and cured at a pressure of 0.2MPa to make the second heat-conducting component fit tightly with the two, forming an efficient heat conduction channel that can quickly conduct the heat generated on the bottom surface of the electrode end to the heat exchange fluid, greatly improving the cooling efficiency.

[0054] To further enhance the reliability and safety of the cooling system, a second heat insulation component is installed on the outer wall of the second pipe 106 located within the heat exchange chamber 102. This second heat insulation component can be a heat insulation coating, employing a nano-composite heat insulation coating. It uses silicone resin as a base material and adds nano-scale heat insulation fillers such as silica aerogel and hollow ceramic microspheres. A uniform and dense coating is formed on the outer wall of the second pipe using a spraying process, with the coating thickness controlled between 0.3 and 0.5 mm. The heat insulation coating is applied using high-pressure airless spraying equipment to ensure uniform coating thickness and prevent drips or missed areas. In this way, the second heat insulation component effectively prevents heat exchange between the heat exchange fluid in the second pipe 106 and the heat exchange fluid inside the heat exchange chamber 102 near the electrode end face, preventing heat from the heat exchange fluid in the second pipe 106 from diffusing into the heat exchange chamber, preventing the heat exchange fluid temperature from rising, ensuring stable operation of the cooling system, and significantly improving the reliability and safety of the cooling process.

[0055] Based on the same inventive concept, this utility model embodiment also provides a DC submerged arc furnace, characterized in that it includes a bottom electrode and a cooling device for the bottom electrode of the DC submerged arc furnace mentioned in the above embodiment. A heat exchange cavity is opened inside the bottom electrode. The part of the bottom electrode with the heat exchange cavity serves as the electrode end and is not inside the DC submerged arc furnace. The electrode end is provided with a first opening and a second opening. The cooling device for the bottom electrode includes: a first pipe and a second pipe; the first opening is used to install the first pipe and the inner sidewall of the first opening is sealed to the outer sidewall of the first pipe; the second opening is used to install the second pipe and the inner sidewall of the second opening is sealed to the outer sidewall of the second pipe; both the first pipe and the second pipe are in communication with the heat exchange cavity, and the first end of the first pipe and the first end of the second pipe are respectively located on opposite sides of the heat exchange cavity. The first end of the first pipe is close to the end face of the electrode end. The cooling medium enters the heat exchange cavity from the first end of the first pipe, circulates, and then flows out of the heat exchange cavity through the first end of the second pipe. The distance from the first end of the first pipe to the center of the DC submerged arc furnace is less than the distance from the first end of the second pipe to the center of the DC submerged arc furnace.

[0056] It is worth noting that the DC electric arc furnace provided in this embodiment and the cooling device of the DC electric arc furnace described above belong to the same inventive concept. For the same or similar technical solutions and beneficial effects, they can be referred to each other. This embodiment will not be described again here.

[0057] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0058] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A cooling device for the bottom electrode of a DC submerged arc furnace, characterized in that, The DC submerged arc furnace includes a bottom electrode, and a heat exchange cavity is provided inside the bottom electrode. The portion of the bottom electrode with the heat exchange cavity serves as the electrode end and is not inside the DC submerged arc furnace. The electrode end is provided with a first opening and a second opening. The cooling device for the bottom electrode includes a first pipe and a second pipe. The first opening is used to install the first pipe, and the inner wall of the first opening is sealed to the outer wall of the first pipe. The second opening is used to install the second pipe, and the inner wall of the second opening is sealed to the outer wall of the second pipe. Both the first pipe and the second pipe are in communication with the heat exchange cavity. The first end of the first pipe and the first end of the second pipe are located on opposite sides of the heat exchange cavity. The first end of the first pipe is close to the end face of the electrode end. The cooling medium enters the heat exchange cavity from the first end of the first pipe, circulates, and then flows out of the heat exchange cavity through the first end of the second pipe. The distance from the first end of the first pipe to the center of the DC submerged arc furnace is less than the distance from the first end of the second pipe to the center of the DC submerged arc furnace.

2. The cooling device for the bottom electrode of a DC submerged arc furnace according to claim 1, characterized in that, The electrode end includes an end face and a sealing element. The heat exchange cavity, the first opening and the second opening are near the bottom electrode of the DC submerged arc furnace, which is exposed on the end face of the electrode end outside the DC submerged arc furnace. The end face is provided with an opening and the diameter of the opening is the same as the diameter of the heat exchange cavity. The sealing element is sealed to the opening. The heat exchange cavity extends axially from the opening toward the interior of the electrode end. Both the first opening and the second opening are provided through the sealing element. The first pipe communicates with the heat exchange cavity through the first opening, and the second pipe communicates with the heat exchange cavity through the second opening.

3. The cooling device for the bottom electrode of a DC submerged arc furnace according to claim 2, characterized in that, The cooling device further includes a first tensioning member and a first sealing and fixing member; The first tensioning member is disposed inside the heat exchange cavity and fixed to the side wall of the electrode end. The sealing member is also provided with a third opening along the axial direction. The sealing member is fixed to the end face by the cooperation of the first sealing fixing member and the first tensioning member. The first sealing fixing member passes through the third opening and cooperates with the first tensioning member. The first sealing fixing member is fixed after passing through the third opening so that the sealing member is relatively fixed.

4. The cooling device for the bottom electrode of a DC submerged arc furnace according to claim 3, characterized in that, The cooling device further includes: a first support frame, a first heat-conducting element, and a first heat-insulating element. The first support frame is disposed inside the heat exchange cavity and is fixedly connected to the inner side wall of the electrode end. The portion of the second pipe located inside the heat exchange cavity passes through the first support frame, so as to support the portion of the second pipe located inside the heat exchange cavity by the first support frame, so as to prevent the portion of the second pipe located inside the heat exchange cavity from bending or shaking. The first support frame is disposed on one side of the second end of the second pipe for supporting the second pipe. The first heat-conducting element is disposed between the contact surface of the first support frame and the inner sidewall of the electrode end and is tightly connected to the first support frame and the inner sidewall of the electrode end, so as to conduct the heat of the electrode end to the first support frame and exchange heat with the cooling medium. The first heat insulation element is disposed between the contact surfaces of the first support frame and the outer side wall of the second pipe, and is tightly connected to the outer side wall of the first support frame and the second pipe to prevent the heat of the cooling medium in the second pipe from being conducted into the interior of the heat exchange chamber.

5. The cooling device for the bottom electrode of a DC submerged arc furnace according to claim 1, characterized in that, The electrode end includes an end face and a sealing element. The end face has an opening with the same diameter as the heat exchange cavity. The sealing element is sealed to the opening. The heat exchange cavity extends axially from the opening toward the interior of the electrode end. Both the first opening and the second opening are formed on the sidewall of the electrode end. The first pipe communicates with the heat exchange cavity through the first opening, and the second pipe communicates with the heat exchange cavity through the second opening. The portion of the first pipe located in the heat exchange cavity and the portion of the second pipe located in the heat exchange cavity are perpendicular to each other.

6. The cooling device for the bottom electrode of a DC submerged arc furnace according to claim 5, characterized in that, The cooling device further includes a second tensioning member and a second sealing and fixing member; One end of the second tensioning member is fixedly connected to the portion of the first pipe located in the heat exchange chamber. The sealing member is also provided with a fourth opening along the axial direction. The sealing member is fixed to the end face by the cooperation of the second sealing fixing member and the second tensioning member. The second sealing fixing member passes through the fourth opening and cooperates with the second tensioning member. The other end of the second sealing fixing member passes through the fourth opening and is fixed, so that the sealing member and the portion of the first pipe located in the heat exchange chamber are relatively fixed.

7. The cooling device for the bottom electrode of a DC submerged arc furnace according to claim 6, characterized in that, The first pipe extending into the heat exchange chamber has multiple water outlet holes on its pipe wall, and the inner wall of the heat exchange chamber is coated with an insulating and thermally conductive coating.

8. The cooling device for the bottom electrode of a DC submerged arc furnace according to claim 6, characterized in that, The cooling device further includes a second support frame, which is disposed inside the heat exchange chamber; The second pipe includes a first sub-pipe and a second sub-pipe. The first sub-pipe is sealed to the second opening, and the second sub-pipe is sealed to the first sub-pipe through a connector. The first sub-pipe extends radially along the heat exchange cavity, and the second sub-pipe extends axially along the heat exchange cavity. The first sub-pipe extends radially along the heat exchange chamber, and the second end of the second sub-pipe is close to the bottom of the electrode end. The second support frame is disposed on one side of the second end of the second sub-pipe, and the second sub-pipe passes through the second support frame to support the second sub-pipe and prevent the second sub-pipe from bending and shaking. The portion of the second sub-pipe located within the heat exchange chamber points towards the center of the furnace. A buffer hole is provided on the inner wall of the bottom electrode corresponding to the outlet of the first end of the portion of the first pipe located within the heat exchange chamber. The diameter of the buffer hole is larger than the outer diameter of the first pipe, and the first end of the portion of the first pipe located within the heat exchange chamber is located in the buffer hole. This allows the impact force of the cooling medium to be exchanged through the buffer hole, ensuring that the cooling medium entering the heat exchange chamber flows stably and directionally towards the drain outlet corresponding to the second end of the second sub-pipe.

9. The cooling device for the bottom electrode of a DC submerged arc furnace according to claim 1, characterized in that, The cooling device further includes: a second heat-conducting element and a second heat-insulating element; The second heat-conducting element is disposed on the bottom surface of the electrode end to conduct the heat at the bottom of the electrode end to the interior of the heat exchange cavity for heat exchange with the cooling medium; The second heat insulation element is disposed on the outer wall of the second pipe to prevent the cooling medium in the second pipe from exchanging heat with the cooling medium inside the heat exchange chamber.

10. A DC submerged arc furnace, characterized in that, The device includes a bottom electrode and a cooling device for the bottom electrode of a DC submerged arc furnace as described in any one of claims 1-9. The bottom electrode has a heat exchange cavity inside, and the portion of the bottom electrode with the heat exchange cavity serves as the electrode end and is not inside the DC submerged arc furnace. The electrode end is provided with a first opening and a second opening. The cooling device for the bottom electrode includes a first pipe and a second pipe. The first opening is used to install the first pipe, and the inner wall of the first opening is sealed to the outer wall of the first pipe. The second opening is used to install the second pipe, and the inner wall of the second opening is sealed to the outer wall of the second pipe. Both the first pipe and the second pipe are in communication with the heat exchange cavity. The first end of the first pipe and the first end of the second pipe are located on opposite sides of the heat exchange cavity. The first end of the first pipe is close to the end face of the electrode end. The cooling medium enters the heat exchange cavity from the first end of the first pipe, circulates, and then flows out of the heat exchange cavity through the first end of the second pipe. The distance from the first end of the first pipe to the center of the DC submerged arc furnace is less than the distance from the first end of the second pipe to the center of the DC submerged arc furnace.

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