A new type of medium-frequency furnace head

Abstract

This utility model discloses a novel medium-frequency furnace head, comprising a furnace head base. A shielding copper plate is fixed to the inner wall of the furnace head base by stainless steel bolts, and hook-shaped anchors are anchored on the inner side of the shielding copper plate, further reinforced by welding. A layer of ceramic fiber blanket ring is laid on the outer wall of the shielding copper plate. An upper shielding ring is provided inside the ceramic fiber blanket ring, and a coil copper tube is embedded within the upper shielding ring. The outer side of the coil copper tube is covered with the outer wall of the copper tube ceramic fiber blanket. The medium-frequency furnace head proposed in this utility model, through the design of the shielding copper plate and hook-shaped anchors, effectively shields the magnetic field, reduces magnetic leakage, and improves electrical efficiency. The multi-layer ceramic fiber blanket insulation layer significantly saves energy and reduces consumption. The segmented refractory material and isolation plate structure enhances thermal shock resistance. The coil is fixed by both interlocking and bonding, ensuring stable and reliable operation and significantly extending the overall lifespan.

Description

Technical Field

[0001] This utility model relates to the field of medium frequency furnace technology, and in particular to a novel medium frequency furnace burner head. Background Technology

[0002] In a medium-frequency induction furnace, a certain alternating current is passed through a spiral coil made of hollow rectangular copper tubes. According to the right-hand screw rule, the magnetic field lines pass through the metal charge in the furnace chamber, generating an induced current within a certain depth of the metal charge, causing induction heating. Under the action of induction heating, the temperature of the metal charge gradually increases until it melts into molten metal. After the metal charge in the furnace chamber is completely melted, the furnace body can be tilted, and the molten metal can be poured out through the nozzle on the furnace head to complete subsequent casting operations.

[0003] Currently, most medium-frequency furnace heads use Y-shaped anchors staggered and welded to the inner circular surface of the furnace head to fix the refractory material and the furnace body steel structure together. The upper shielding ring is also welded to the lower part of the inner circular surface of the furnace head. However, the anchors are made by cutting steel plates and bending them into Y shapes. This results in the anchors having intersecting right-angled sides, and many Y-shaped anchors are welded to the entire inner circular surface of the furnace head. These many staggered right-angled sides are in direct contact with the cast refractory material. During the furnace heating, melting, and pouring of molten metal, the temperature of the furnace head refractory material changes repeatedly. Due to the different shrinkage ratios of the refractory material and the anchors, and the many rigid right-angled contacts, many small cracks may initially form on the contact surface between the anchors and the refractory material. Then, as the melting process continues, these small cracks gradually extend, intersect, and slowly form large cracks. Cooling water is circulated inside the shielding ring. Under operating conditions, the large temperature difference between the shielding ring and the refractory material also increases the risk of refractory material cracking to some extent.

[0004] In addition, the entire furnace head refractory is integrally cast and directly contacts the inner circular surface of the furnace head steel structure. Since the temperature of each part of the medium frequency furnace will change significantly during the entire melting process, and the furnace body will also vibrate to a certain extent, this arrangement reduces the adaptability of the furnace head refractory to temperature changes and increases the degree of cracking and rupture. Utility Model Content

[0005] The purpose of this utility model is to address the shortcomings of existing technologies by proposing a novel medium-frequency furnace head.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A novel medium-frequency furnace head includes a furnace head base. A shielding copper plate is fixed to the inner wall of the furnace head base by stainless steel bolts. The inner side of the shielding copper plate is anchored with claw-shaped anchors and further reinforced by welding. A layer of ceramic fiber blanket ring is laid on the outer wall of the shielding copper plate. An upper shielding ring is provided inside the ceramic fiber blanket ring, and a coil copper tube is embedded in the upper shielding ring. The outer side of the coil copper tube is covered with a ceramic fiber blanket.

[0008] The inner side of the ceramic fiber blanket on the outer wall of the copper tube is provided with three equally spaced furnace head refractory materials, and a refractory material isolation plate is provided between two adjacent furnace head refractory materials.

[0009] Preferably, the outer wall of the hook-shaped anchor is covered with a layer of crepe paper or crepe paper-like material.

[0010] Preferably, the refractory isolation plate is made of high-temperature resistant mica plate superimposed with high-temperature resistant ceramic fiber blanket.

[0011] Preferably, the coil turns of the copper coil tube are interlocked with G10 insulating blocks in multiple layers, and the contact surfaces of the G10 insulating blocks and the copper coil tube are coated with strong heat-resistant adhesive.

[0012] Preferably, the ceramic fiber blanket ring and the outer wall ceramic fiber blanket of the copper tube are made of 5mm thick ceramic fiber blanket with a temperature resistance of 1260℃.

[0013] Preferably, the furnace head base is provided with a furnace cover on top, a furnace chamber is provided on the furnace head base, a furnace bottom assembly is installed at the bottom of the furnace chamber, and crucible refractory, induction coil and magnetic yoke are arranged in sequence on the outside of the furnace chamber.

[0014] The beneficial effects of this utility model are as follows:

[0015] 1. By fixing the shielding copper plate to the inner wall of the furnace head substrate and using a double fixing method of hook-shaped anchors combined with welding, the mechanical strength and reliability of the shielding structure are greatly enhanced. This design can effectively shield and guide stray magnetic fields, reduce magnetic leakage, improve electrical efficiency, and at the same time ensure the structural integrity of the furnace head under long-term operation and thermal expansion and contraction.

[0016] 2. A ceramic fiber blanket is laid on the outer wall of the shielding copper plate and wrapped with a ceramic fiber blanket on the outside of the coil copper tube, forming a highly efficient multi-layer heat insulation barrier. This not only significantly reduces the transfer of heat to the furnace head substrate, lowers the furnace surface temperature, and saves energy, but also effectively buffers the thermal stress caused by rapid temperature changes and extends the overall service life of the furnace head.

[0017] 3. The furnace head refractory is constructed using three equidistantly distributed sections, with a refractory isolation plate made of mica sheet and ceramic fiber blanket between them. This structural design divides the overall refractory material, effectively absorbing and offsetting thermal expansion stress, and preventing the refractory from cracking or peeling due to compression during thermal cycling. The composite structure of mica sheet and ceramic fiber blanket further provides flexible cushioning and additional thermal insulation, together significantly improving the thermal shock resistance and durability of the furnace head refractory.

[0018] 4. G10 insulating blocks are used between the coil turns and embedded in multiple interlocking layers, while a strong, high-temperature resistant adhesive is applied to the contact surfaces. This dual fixing method of "mechanical interlocking + chemical bonding" ensures that the coil will not shift or wear under electromagnetic force and vibration, greatly enhancing the overall rigidity and operational reliability of the coil system. The excellent insulation and mechanical properties of G10 material guarantee safe and stable operation under long-term high-temperature environments.

[0019] In summary, the medium-frequency furnace head proposed in this utility model effectively shields the magnetic field, reduces magnetic leakage, and improves electrical efficiency through the design of shielding copper plates and hook anchors. The multi-layer ceramic fiber blanket insulation layer significantly saves energy and reduces consumption. The segmented refractory material and isolation plate structure enhances thermal shock resistance. The coil adopts a double fixation of interlocking and bonding to ensure stable and reliable operation and significantly extend the overall service life. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the main cross-sectional structure of a novel medium-frequency furnace head proposed in this utility model;

[0021] Figure 2 This is a side sectional view of the medium-frequency induction furnace of this utility model.

[0022] Figure 3 This is a schematic diagram of the coil-turn stacked insulation block structure of a novel medium-frequency furnace head proposed in this utility model.

[0023] In the diagram: 1. Furnace head substrate; 2. Furnace head refractory material; 3. Refractory material isolation plate; 4. Ceramic fiber blanket ring; 5. Hook-shaped anchor; 6. Ceramic fiber blanket on the outer wall of copper tube; 7. Shielding copper plate; 8. Upper shielding ring; 9. Furnace cover; 10. Furnace chamber; 11. Crucible refractory material; 12. Induction coil; 13. Magnetic yoke; 14. Furnace bottom assembly; 15. G10 insulating block. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0025] Example 1, referring to Figure 1-3 A new type of medium-frequency furnace head, such as Figure 1 As shown.

[0026] A 5mm thick copper plate 7 is fixed to the inner wall of the furnace head with stainless steel bolts to prevent the magnetic field lines generated by the induction coil from passing through the furnace head steel structure. For induction heating of the furnace head, 6mm diameter copper rods are bent into hook-shaped anchors as shown in part 5 and welded to the shielding copper plate 7 in two staggered rows. All anchors are then wrapped with crepe paper or similar material to reduce the probability of cracking in the furnace head refractory material caused by the anchors. Before casting the furnace head refractory material, a 5mm thick ceramic fiber blanket with a temperature resistance of 1260℃ is laid on the inner wall of the shielding copper plate 7. Then, the copper tubes on the upper shielding ring are also tightly wrapped with ceramic fiber blankets to further prevent cracking in the furnace head refractory material. A refractory isolation plate 3 is made by layering high-temperature resistant mica plates with ceramic fiber blankets, and three plates are evenly distributed in the inner cavity of the furnace head.

[0027] like Figure 1 As shown, the entire furnace head refractory is divided into three parts, with buffer layers between each part, which can effectively solve the cracking phenomenon caused by refractory temperature changes and furnace vibration.

[0028] After prolonged use, the induction coil turns of an intermediate frequency furnace will experience torsional misalignment due to the long-term effect of electromagnetic force. The furnace head refractory 2 is secured to the coil by bolts distributed around its circumference. This torsional misalignment of the induction coil will cause displacement on the pressing surface between the induction coil and the furnace head refractory 2, potentially leading to cracks. To achieve both resistance to vertical pressure and torsional force, G10 insulating blocks 15 are used between the coil turns, embedded in multiple layers in an interlocking manner. A strong, heat-resistant adhesive is applied to the contact surface with the coil copper tube. Figure 3 As shown in the figure. Practical experience has verified that it has achieved good results.

[0029] Working principle:

[0030] Electromagnetic shielding and guidance principles:

[0031] The core component is the shielding copper plate 8 installed on the inner wall of the furnace head base 1. Its working principle is based on the principle of electromagnetic induction. When an alternating magnetic field attempts to pass through, a strong eddy current is generated in the copper plate. The reverse magnetic field generated by this eddy current can effectively cancel and guide the original stray magnetic field, preventing it from penetrating to the outer steel structure furnace head base 1, thereby preventing it from being inductively heated. This not only improves the efficiency of energy utilization but also protects the furnace structure.

[0032] Thermal stress buffering and insulation principle:

[0033] Multi-layer flexible heat insulation layer: The ceramic fiber blanket ring 4 and the ceramic fiber blanket 6 on the outer wall of the copper tube and the inner wall of the shielding copper plate 8 serve as a flexible buffer layer and a high-efficiency heat insulation layer. Its working principle is twofold: first, to use the extremely low thermal conductivity of the ceramic fiber blanket to block the heat transfer to the furnace head substrate 1, thereby achieving energy saving; second, to use its good compression resilience to absorb the stress generated by the furnace head refractory 2 during thermal expansion and contraction, thereby avoiding stress concentration.

[0034] Segmented refractory stress relief structure: The entire furnace head refractory 2 is divided into three independent parts by refractory isolation plate 3. Its working principle is to transform a large, integral brittle structure into multiple small, independently micro-moving units. The mica plate and ceramic fiber blanket composite layer between each unit act as "expansion joints" and "buffer zones", which can effectively absorb and offset the transverse and longitudinal stresses caused by temperature fluctuations and furnace vibration, thereby fundamentally preventing the refractory from developing through cracks.

[0035] The principle of coil anti-torsion and rigid fixation:

[0036] To address the problem of torsional misalignment between coil turns caused by electromagnetic force, a dual fixing scheme of "mechanical interlocking + chemical bonding" was adopted.

[0037] The G10 insulating block 15 is embedded between the coil turns in a multi-layer interlocking manner. Its working principle is to form an integral grid skeleton that runs through each layer of coil, distributing the force of a single coil to the entire grid structure, and using the high mechanical strength of G10 material to resist the torsional tendency caused by electromagnetic force.

[0038] The high-strength, heat-resistant adhesive further fills all the microscopic gaps, firmly bonding the coil copper tube to the G10 insulating block 15 into a single unit. This "rigid-flexible" fixing method ensures that the coil system has extremely high overall rigidity and stability, eliminating displacement of the furnace head refractory pressing surface caused by coil micro-movements, thereby cutting off another path that could lead to refractory cracking.

[0039] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A novel medium-frequency furnace head, comprising a furnace head base (1), characterized in that, The inner wall of the furnace head base (1) is fixed with a shielding copper plate (7) by stainless steel bolts, and the inner side of the shielding copper plate (7) is anchored with a claw-shaped anchor (5), and further reinforced by welding. A layer of ceramic fiber blanket ring (4) is laid on the outer wall of the shielding copper plate (7). An upper shielding ring (8) is provided on the inner side of the ceramic fiber blanket ring (4), and a coil copper tube is embedded in the upper shielding ring (8). The outer side of the coil copper tube is covered with a copper tube outer wall ceramic fiber blanket (6). The inner side of the ceramic fiber blanket (6) on the outer wall of the copper tube is provided with three equally spaced furnace head refractory materials (2), and a refractory material isolation plate (3) is provided between two adjacent furnace head refractory materials (2).

2. The novel medium-frequency furnace head according to claim 1, characterized in that, The outer wall of the hook-shaped anchor (5) is covered with a layer of crepe paper or crepe-like material.

3. The novel medium-frequency furnace head according to claim 1, characterized in that, The refractory isolation plate (3) is made of high-temperature resistant mica plate superimposed with high-temperature resistant ceramic fiber blanket.

4. The novel medium-frequency furnace head according to claim 1, characterized in that, The coil copper tube uses G10 insulating blocks (15) between the coil turns and embeds them in multiple layers in an interlocking manner. The contact surfaces of the G10 insulating blocks (15) and the coil copper tube are coated with strong heat-resistant adhesive.

5. A novel medium-frequency furnace head according to claim 1, characterized in that, The ceramic fiber blanket ring (4) and the ceramic fiber blanket (6) on the outer wall of the copper tube are made of 5mm thick ceramic fiber blankets with a temperature resistance of 1260℃.

6. A novel medium-frequency furnace head according to claim 1, characterized in that, The furnace head base (1) is provided with a furnace cover (9) on top, and a furnace chamber (10) is provided on the furnace head base (1). A furnace bottom assembly (14) is installed at the bottom of the furnace chamber (10). A crucible refractory material (11), an induction coil (12) and a magnetic yoke (13) are arranged in sequence on the outside of the furnace chamber (10).

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