Submerged entry nozzle electric heating baking device

Abstract

The utility model provides a kind of submerged entry nozzle electric heating baking device, including hearth shell, the wall of hearth shell includes nanometer microporous heat insulation plate layer, light clay brick layer and high-alumina refractory brick layer in turn from outside to inside, hearth shell is equipped with one or more heat-resistant partition, for the inner cavity of hearth shell is divided into multiple baking chambers, each baking chamber is used to install submerged entry nozzle, each baking chamber is evenly arranged with multiple silicon carbide heating rods around the periphery of submerged entry nozzle, the cold end of each silicon carbide heating rod is passed through hearth shell and is connected with power supply, hearth shell is equipped with insulating sealing sleeve pipe at the wall penetration position of each silicon carbide heating rod. It can meet the high-temperature preheating demand of submerged entry nozzle, and multiple submerged entry nozzles can be simultaneously and evenly electrically heated and radiantly baked, the temperature field distribution of submerged entry nozzle is uniform, local stress concentration problem is not prone to occur, and the heat insulation effect of hearth shell is good, heat loss is small, and energy utilization rate is high.

Description

Technical Field

[0001] This utility model belongs to the field of metallurgical equipment technology, specifically relating to an immersion-type electric heating baking device for water inlets. Background Technology

[0002] The submerged entry nozzle (SEN), also known as the bottom nozzle, is a key functional refractory component in continuous casting production. Installed between the bottom of the tundish and the crystallizer, its main function is to continuously and stably guide the high-temperature molten steel from the tundish into the crystallizer, while preventing secondary oxidation of the molten steel during casting. Because the SEN directly withstands the impact of the high-temperature molten steel during service, if it is not adequately preheated before contacting the molten steel, its refractory material will experience significant internal thermal stress due to the severe thermal shock, easily leading to refractory material cracking, molten steel contamination, or even steel leakage and other serious production accidents. Therefore, before using the SEN, it must be thoroughly preheated, typically to a temperature close to the operating temperature of 800-1100℃, to completely remove moisture from the refractory material and effectively eliminate thermal stress.

[0003] Currently, the industry mainly uses the following methods for preheating and baking immersion gates:

[0004] 1) Gas-fired heating method: This method uses a high-temperature flame generated by a natural gas or coal gas burner to directly heat the submerged entry nozzle. However, in practical applications, gas-fired heating has inherent technical drawbacks: First, open flame operations pose safety hazards, and the large amount of high-temperature flue gas (including CO2, NOx, and water vapor) generated during combustion directly erodes the refractory material surface of the submerged entry nozzle, easily causing chemical corrosion of the refractory material surface; second, relevant studies have shown that, limited by the directionality of the flame jet and the structure of the heating chamber, gas-fired heating is prone to causing uneven circumferential and axial temperature field distribution of the submerged entry nozzle, which in turn easily leads to local stress concentration problems; in addition, the gas-fired heating system requires complex gas pipelines, valve groups, and safety interlock control devices, which not only occupy a large area but also make daily management and maintenance complex.

[0005] 2) Traditional Simple Electric Heating Baking Method: Some steel mills use traditional simple electric heating baking devices based on resistance wires or infrared heating lamps. However, these simple electric heating baking devices generally have the following shortcomings: First, the power density of the heating elements is low, resulting in limited heating temperature, usually not exceeding 800℃, which is difficult to meet the high-temperature preheating requirements of modern continuous casting processes for submerged entry nozzles; Second, the service life of the heating elements is short, requiring frequent replacement, which seriously affects the production line's operating rate; Third, the furnace body insulation structure is relatively simple, resulting in significant heat loss and low energy utilization efficiency. Utility Model Content

[0006] In view of the above-mentioned defects of the prior art, the present invention provides an immersion-type sprue electric heating baking device, which can meet the high-temperature preheating requirements of immersion-type sprues and can simultaneously perform uniform electric heating radiation baking on multiple immersion-type sprues. The temperature field distribution of the immersion-type sprues is uniform, and it is not easy to have local stress concentration problems. In addition, the furnace shell has good heat insulation effect, low heat loss, and high energy utilization rate.

[0007] The technical solution adopted by this utility model to solve its technical problem is:

[0008] An immersion-type electric heating baking device includes a furnace shell. The wall of the furnace shell, from the outside to the inside, includes a nanoporous heat insulation plate layer, a lightweight clay brick layer, and a high-alumina refractory brick layer. One or more heat-resistant partitions are provided inside the furnace shell to divide the inner cavity of the furnace shell into multiple baking chambers. Each baking chamber is used to install the immersion nozzle to be baked. Multiple silicon carbide heating rods are evenly arranged around the immersion nozzle in each baking chamber. The cold end of each silicon carbide heating rod protrudes from the furnace shell and is connected to a power source. An insulating sealing sleeve is provided on the furnace shell at the wall penetration position of each silicon carbide heating rod to isolate the electrical connection between the furnace shell and the corresponding silicon carbide heating rod and to seal the gap between the furnace shell and the corresponding silicon carbide heating rod.

[0009] Furthermore, the furnace shell wall is provided with a furnace steel plate on the outside of the nanoporous heat insulation plate layer.

[0010] Furthermore, the heat-resistant partition wall is a single wall arranged horizontally in the middle of the furnace shell, used to divide the inner cavity of the furnace shell into two baking chambers with the same structure and size.

[0011] Furthermore, the front end of the furnace shell is provided with a furnace door mounting opening at a position corresponding to each baking chamber, and a furnace door is installed at each furnace door mounting opening. The door panel structure of each furnace door is the same as the wall structure of the furnace shell, and a high-temperature resistant sealing strip is provided between each furnace door and the corresponding door frame on the furnace shell.

[0012] Furthermore, the upper end of the immersion sprue in each of the baking chambers is detachably connected to the inner top surface of the corresponding baking chamber via a flange and is vertically suspended in the middle position of the corresponding baking chamber.

[0013] Furthermore, each of the silicon carbide heating rods is arranged vertically, and the heating part of each silicon carbide heating rod extends from top to bottom into the upper and lower baking chambers, while the cold end of each silicon carbide heating rod protrudes from the top wall of the furnace shell.

[0014] Furthermore, the furnace shell is rectangular in shape, and a cabinet with a structure and size that are compatible with the furnace shell is provided on the outside of the furnace shell. The front end of the cabinet is open and forms a furnace shell mounting port for installing the furnace shell.

[0015] Furthermore, the cabinet includes a cabinet frame, and the left, right, rear, top and bottom ends of the cabinet frame are all encapsulated with cabinet steel plates, and the cabinet steel plates on the cabinet are attached to the furnace steel plates at corresponding positions on the furnace shell.

[0016] Furthermore, the power source is a copper busbar, and the cold ends of each silicon carbide heating rod pass through the top wall of the furnace shell and the top wall of the cabinet in sequence, and are electrically connected to the copper busbar installed on the top surface of the cabinet via an aluminum braided connecting strip.

[0017] Furthermore, the insulating sealing sleeve is a ceramic insulating sealing sleeve.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] The immersion-type sprue electric heating baking device of this utility model includes a furnace shell. The wall of the furnace shell includes, from the outside to the inside, a nanoporous heat insulation plate layer, a lightweight clay brick layer, and a high-alumina refractory brick layer. One or more heat-resistant partitions are provided inside the furnace shell to divide the inner cavity of the furnace shell into multiple baking chambers. Each baking chamber is used to install the immersion sprue to be baked. Multiple silicon carbide heating rods are evenly arranged around the immersion sprue in each baking chamber. The cold end of each silicon carbide heating rod protrudes from the furnace shell and is connected to a power source. An insulating sealing sleeve is provided on the furnace shell at the wall penetration position of each silicon carbide heating rod to isolate the electrical connection between the furnace shell and the corresponding silicon carbide heating rod and to seal the gap between the furnace shell and the corresponding silicon carbide heating rod. This baking device uses silicon carbide heating rods for electric radiant baking of submerged nozzles. The silicon carbide heating rods have high power density and can operate stably for extended periods at temperatures above 1200℃ without deformation, eliminating the need for frequent replacements. This meets the high-temperature preheating requirements of submerged nozzles. Furthermore, the electric heating baking method of this device avoids the inherent technical defects of traditional gas-fired baking methods, such as the safety hazards of open flame operations and the chemical corrosion caused by direct erosion of the refractory material surface by high-temperature flue gas. It also eliminates the need for complex gas pipelines, valve assemblies, and safety interlock control devices, resulting in a small footprint and simple daily management and maintenance. The device includes multiple baking chambers, each with multiple silicon carbide heating rods evenly distributed around the submerged nozzle, allowing for simultaneous baking of multiple nozzles. Uniform electric heating radiation baking can meet the needs of continuous casting with multiple streams simultaneously changing submerged entry nozzles. The temperature field distribution of the submerged entry nozzles is uniform, and local stress concentration is less likely to occur. In addition, the furnace shell wall consists of a nanoporous heat insulation plate layer, a lightweight clay brick layer, and a high-alumina refractory brick layer from the outside to the inside. The nanoporous heat insulation plate layer and the lightweight clay brick layer both play a heat insulation role, while the high-alumina refractory brick layer serves as a working layer and has a high-temperature resistance. This three-layer composite structure makes the heat insulation effect of the furnace shell far exceed that of traditional furnaces with single or double refractory linings. When the furnace shell is operating at 1300℃, the temperature of its outer wall can be controlled below 60℃. Therefore, the overall thermal resistance of this furnace shell is extremely high, which can significantly reduce heat loss and environmental heat radiation hazards, and significantly improve energy utilization. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the main cross-sectional structure of the immersion-type electric heating baking device of this utility model;

[0021] Figure 2 A schematic diagram showing the connection between each silicon carbide heating rod and the furnace shell via an insulating and sealing sleeve.

[0022] Figure 3 for Figure 2 Enlarged structural diagram of section A in the middle frame;

[0023] Figure 4 This is a schematic diagram of a partial cross-sectional view of the furnace shell wall.

[0024] The following are the labels in the attached figures: 1. Furnace shell; 101. Nanoporous heat insulation board layer; 102. Lightweight clay brick layer; 103. High-alumina refractory brick layer; 104. Furnace steel plate; 2. Heat-resistant partition wall; 3. Baking chamber; 4. Immersion nozzle; 5. Silicon carbide heating rod; 501. Heating element; 502. Cold end; 6. Insulating sealing sleeve; 7. Flange; 8. Cabinet; 9. Cabinet base. Detailed Implementation

[0025] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings. These embodiments are only used to illustrate this utility model and are not intended to limit it.

[0026] In the description of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0028] Furthermore, in the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0029] like Figure 1 As shown, an immersion-type electric heating baking device includes a furnace shell 1. The wall of the furnace shell 1, from the outside to the inside, includes a nanoporous heat insulation plate layer 101, a lightweight clay brick layer 102, and a high-alumina refractory brick layer 103. Figure 1 and Figure 4The furnace shell 1 is provided with one or more heat-resistant partition walls 2 to divide the inner cavity of the furnace shell 1 into multiple baking chambers 3. Each baking chamber 3 is used to install the immersion nozzle 4 to be baked. Multiple silicon carbide heating rods 5 are evenly arranged around the immersion nozzle 4 in each baking chamber 3. The cold end 502 of each silicon carbide heating rod 5 protrudes from the furnace shell 1 and is connected to the power supply. An insulating sealing sleeve 6 is provided on the furnace shell 1 at the wall penetration position of each silicon carbide heating rod 5. See Figure 2 and Figure 3 It is used to isolate the electrical connection between the furnace shell 1 and the corresponding silicon carbide heating rod 5 and to seal the gap between the furnace shell 1 and the corresponding silicon carbide heating rod 5.

[0030] This baking device uses silicon carbide heating rods 5 to electrically heat and radiate heat the submerged nozzles 4. The silicon carbide heating rods 5 have high power density and can operate stably for extended periods at temperatures above 1200℃ without deformation, eliminating the need for frequent replacement. This meets the high-temperature preheating requirements of the submerged nozzles 4. Furthermore, the electric heating baking method of this device avoids the inherent technical defects of traditional gas-fired baking methods in the background technology, namely, the safety hazards of open flame operations and the chemical corrosion caused by direct erosion of the refractory material surface of the submerged nozzles 4 by high-temperature flue gas. It also eliminates the need for complex gas pipelines, valve assemblies, and safety interlock control devices, resulting in a small footprint and simple daily management and maintenance. The device includes multiple baking chambers 3, each containing multiple silicon carbide heating rods 5 evenly distributed around the submerged nozzles 4, allowing for simultaneous and uniform electric heating of multiple submerged nozzles 4. Thermal radiation baking can meet the needs of continuous casting with multiple streams simultaneously changing the submerged entry nozzle 4, and the temperature field distribution of the submerged entry nozzle 4 is uniform, making it less prone to local stress concentration problems. In addition, the wall of the furnace shell 1 consists of a nanoporous heat insulation plate layer 101, a lightweight clay brick layer 102, and a high-alumina refractory brick layer 103 from the outside to the inside. The nanoporous heat insulation plate layer 101 and the lightweight clay brick layer 102 both play a heat insulation role, while the high-alumina refractory brick layer 103 serves as a working layer and has a high-temperature resistance. In this way, the heat insulation effect of the furnace shell 1 through the three-layer composite structure is far superior to that of traditional furnaces with single or double refractory linings. When the baking chamber 3 of the furnace shell 1 is running at 1300℃, the temperature of its outer wall can be controlled below 60℃. Therefore, the overall thermal resistance of this furnace shell 1 is extremely high, which can significantly reduce heat loss and environmental heat radiation hazards, and significantly improve energy utilization.

[0031] In addition, since the cold end 502 of each silicon carbide heating rod 5 protrudes through the furnace shell 1, each silicon carbide heating rod 5 is installed in the furnace shell 1 by means of penetration. Therefore, the replacement and maintenance of each silicon carbide heating rod 5 is convenient. Furthermore, an insulating sealing sleeve 6 is provided at the penetration position of each silicon carbide heating rod 5 on the furnace shell 1. The insulating sealing sleeve 6 can isolate the electrical connection between the furnace shell 1 and the corresponding silicon carbide heating rod 5, and can also seal the gap between the furnace shell 1 and the corresponding silicon carbide heating rod 5.

[0032] The furnace shell 1 has a furnace steel plate 104 on the outside of the nanoporous heat insulation plate layer 101. Figure 1 and Figure 4 The 104 stainless steel plate in the furnace chamber serves as a structural support.

[0033] In one embodiment, the heat-resistant partition 2 is a horizontally arranged wall located in the middle of the furnace shell 1, which is used to divide the inner cavity of the furnace shell 1 into two baking chambers 3 with the same structure and size.

[0034] In one preferred embodiment, the front end of the furnace shell 1 is provided with a furnace door mounting opening at a position corresponding to each baking chamber 3, and a furnace door is installed at each furnace door mounting opening. The door panel structure of each furnace door is the same as the wall structure of the furnace shell 1, and a high-temperature resistant sealing strip is provided between each furnace door and the corresponding door frame on the furnace shell 1.

[0035] This design of the furnace door facilitates the installation of immersion nozzles 4 for baking in each baking chamber 3. When the furnace door is closed and locked, the high-temperature resistant sealing strip is pressed to achieve a seal between the furnace door and the corresponding door frame on the furnace shell 1, reducing heat loss.

[0036] In another preferred embodiment, the upper end of the immersion sprue 4 in each baking chamber 3 is detachably connected to the inner top surface of the corresponding baking chamber 3 via a flange 7 and is vertically suspended at the center position within the corresponding baking chamber 3. Figure 1 .

[0037] In this way, the immersion gate 4 can be installed in the corresponding baking chamber 3 simply by detachably connecting the flange 7 at the upper end of the immersion gate 4 to the inner top surface of the corresponding baking chamber 3. Therefore, the installation of the immersion gate 4 is convenient.

[0038] In this design, each silicon carbide heating rod 5 is arranged vertically, with its heating element 501 extending sequentially from top to bottom into the upper and lower baking chambers 3. The cold end 502 of each silicon carbide heating rod 5 protrudes from the top wall of the furnace shell 1. Through holes are provided on the heat-resistant partition wall 2 at the locations where the heating elements 501 of each silicon carbide heating rod 5 pass through. The furnace shell 1 is rectangular in shape, and a cabinet 8 with a structure and dimensions compatible with the furnace shell 1 is provided on its outer side. Figure 1 The front end of the cabinet 8 is opened and forms a furnace shell 1 mounting port for installing the furnace shell 1.

[0039] Since the heating element 501 of each silicon carbide heating rod 5 extends sequentially from top to bottom into the upper and lower baking chambers 3, each silicon carbide heating rod 5 can simultaneously perform electric heating radiation baking on the immersion gates 4 in both upper and lower baking chambers 3. The cabinet 8 serves to fix and house the furnace shell 1.

[0040] Preferably, the cabinet 8 includes a cabinet 8 frame, and the left, right, rear, top, and bottom ends of the cabinet 8 frame are all encapsulated with cabinet 8 steel plates. The cabinet 8 steel plates on the cabinet 8 are fitted with the furnace steel plates 104 at corresponding positions on the furnace shell 1. The cabinet 8 frame is welded from channel steel and angle steel. The bottom of the cabinet 8 is provided with a cabinet base 9, see [link to details]. Figure 1 .

[0041] Preferably, the power supply is a copper busbar, and the cold end 502 of each silicon carbide heating rod 5 passes through the top wall of the furnace shell 1 and the top wall of the cabinet 8 in sequence and is electrically connected to the copper busbar installed on the outer top surface of the cabinet 8 through an aluminum braided connecting strip.

[0042] In one embodiment, the insulating sealing sleeve 6 is a ceramic insulating sealing sleeve.

[0043] In one embodiment, the top wall of the furnace shell 1 is replaced with a high-strength lightweight fiberboard instead of a lightweight clay brick layer 102. Then, the top wall of the furnace shell 1 includes, from the outside to the inside, a nanoporous heat insulation board layer 101, a high-strength lightweight fiberboard, and a high-alumina refractory brick layer 103.

[0044] Specific embodiment: The nanoporous heat insulation plate layer 101 of the furnace shell 1 wall is laid tightly against the inner side of the furnace steel plate 104. The thickness of the nanoporous heat insulation plate layer 101 is 10mm, and its thermal conductivity is extremely low, ≤0.025W / (m·K) at room temperature, thus playing a role in efficient heat insulation. The lightweight clay brick layer 102 is built inside the nanoporous heat insulation plate layer 101. The bricks of the lightweight clay brick layer 102 have a size of 230mm. The standard bricks, measuring 114mm x 65mm, have a density of approximately 1.2g / cm³ and serve as insulation and structural support. The high-alumina refractory brick layer 103 is laid inside the lightweight clay brick layer 102. The high-alumina refractory brick layer 103 has a thickness of 114mm, a density of 2.6g / cm³, and an Al₂O₃ content of ≥55%. It directly faces the high-temperature environment inside the baking chamber 3 and can withstand temperatures ≥1400℃. As a working layer, it plays a role in high-temperature resistance and erosion resistance.

[0045] The silicon carbide heating rod 5 is a straight rod-shaped heating element made of high-purity α-silicon carbide material through extrusion molding and high-temperature recrystallization. The silicon carbide heating rod 5 is a GD-type straight rod with a diameter of 20-40mm. The length of the heating part 501 of the silicon carbide heating rod 5 is matched according to the height of the baking chamber 3. The power of a single silicon carbide heating rod 5 is 3-8kW, and the total heating power of the whole machine is 40-80kW.

[0046] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present utility model, and these improvements and substitutions should also be considered within the protection scope of the present utility model.

Claims

1. An immersion-type electric heating baking device, characterized in that: The furnace includes a furnace shell (1), the walls of which, from the outside to the inside, consist of a nanoporous heat insulation plate layer (101), a lightweight clay brick layer (102), and a high-alumina refractory brick layer (103). The furnace shell (1) contains one or more heat-resistant partition walls (2) to divide the inner cavity of the furnace shell (1) into multiple baking chambers (3). Each baking chamber (3) is used to install an immersion nozzle (4) to be baked. Each baking chamber (3) is surrounded by an immersion nozzle... Multiple silicon carbide heating rods (5) are evenly arranged around the circumference of the water inlet (4). The cold end (502) of each silicon carbide heating rod (5) protrudes through the furnace shell (1) and is connected to the power supply. An insulating sealing sleeve (6) is provided on the furnace shell (1) at the wall penetration position of each silicon carbide heating rod (5) to isolate the electrical connection between the furnace shell (1) and the corresponding silicon carbide heating rod (5) and seal the gap between the furnace shell (1) and the corresponding silicon carbide heating rod (5).

2. The immersion-type electric heating baking device according to claim 1, characterized in that: The furnace shell (1) has a furnace steel plate (104) on the outside of the nanoporous heat insulation plate layer (101).

3. The immersion-type electric heating baking device according to claim 2, characterized in that: The heat-resistant partition (2) is a horizontally arranged wall located in the middle of the furnace shell (1) to divide the inner cavity of the furnace shell (1) into two baking chambers (3) with the same structure and size.

4. The immersion-type electric heating baking device according to claim 3, characterized in that: The front end of the furnace shell (1) is provided with a furnace door installation port at the position corresponding to each baking chamber (3). A furnace door is installed at each furnace door installation port. The door panel structure of each furnace door is the same as the wall structure of the furnace shell (1). A high-temperature resistant sealing strip is provided between each furnace door and the corresponding door frame on the furnace shell (1).

5. The immersion-type electric heating baking device according to claim 3, characterized in that: The upper end of the immersion sprue (4) in each of the baking chambers (3) is detachably connected to the inner top surface of the corresponding baking chamber (3) via a flange (7) and is vertically suspended in the middle position of the corresponding baking chamber (3).

6. The immersion-type electric heating baking device according to claim 5, characterized in that: Each of the silicon carbide heating rods (5) is arranged vertically, and the heating part (501) of each of the silicon carbide heating rods (5) extends from top to bottom into the upper and lower baking chambers (3), and the cold end (502) of each of the silicon carbide heating rods (5) protrudes from the top wall of the furnace shell (1).

7. The immersion-type electric heating baking device according to claim 6, characterized in that: The furnace shell (1) is rectangular in shape. The outer side of the furnace shell (1) is provided with a cabinet (8) that is compatible with the structure and size of the furnace shell (1). The front end of the cabinet (8) is open and forms a furnace shell (1) mounting port for installing the furnace shell (1).

8. The immersion-type electric heating baking device according to claim 7, characterized in that: The cabinet (8) includes a cabinet (8) frame. The left, right, rear, top and bottom ends of the cabinet (8) frame are all encapsulated with cabinet (8) steel plates. The cabinet (8) steel plates on the cabinet (8) are attached to the furnace steel plates (104) at the corresponding positions on the furnace shell (1).

9. The immersion-type electric heating baking device according to claim 7, characterized in that: The power source is a copper busbar. The cold end (502) of each silicon carbide heating rod (5) passes through the top wall of the furnace shell (1) and the top wall of the cabinet (8) in sequence and is electrically connected to the copper busbar installed on the top surface of the cabinet (8) through an aluminum braided connecting strip.

10. The immersion-type electric heating baking device according to claim 2, characterized in that: The insulating sealing sleeve (6) is a ceramic insulating sealing sleeve.

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