Coil assembly with coil section and method of manufacturing thereof

Abstract

The present invention provides coil assembly (200). The coil assembly (200) comprises a first ring assembly (102) at a top portion of the coil assembly (100). The coil assembly (200) further comprises a coil member (112, 200) extending between the first ring assembly (102) and the second ring assembly (116). The coil member (116, 200) comprises a trapezoidal cross-sectioned trench (202). for safer and operationally stable high power density coil assembly. The trapezoidal or triangular cross-sectioned coil (202) causes the enhancement of electrical efficiency with reduction in I2R losses, thermal efficiency with lower conduction heat losses, avoids electrical sparking, and reduces risk of electrical sparking.

Description

[0001] “COILASSEMBLY WITH COIL SECTION AND METHOD OF MANUFACTURING THEREOF”

[0002] FIELD OF THE INVENTION

[0003]

[0002] The present invention relates coil assembly and more particularly, the present disclosure relates to the coil assembly that enhances the efficiency.

[0004] BACKGROUND

[0005]

[0003] Induction furnaces, particularly the coreless type, have gained widespread popularity for melting various metals, their alloys, and derivatives across thousands of foundries and steel plants worldwide. These furnaces are favored for their economic efficiency and adaptability to a broad range of metallurgical requirements. Their melting capacities vary widely, from just a few kilograms up to 100 metric tons, making them suitable for both small-scale and large-scale industrial applications.

[0006]

[0004] A coreless induction furnace operates without a magnetic core, meaning there is no physical component to link the magnetic flux between the primary and secondary elements. The induction coil, typically made from heavy-duty, high- conductivity hollow tubing, is wound into a helical form and acts as the primary energy-transfer element. This coil is enclosed within a steel shell, which is often protected by magnetic shielding to prevent unwanted heating. To manage the significant heat generated during operation, the coil is water-cooled using a recirculation system connected to a cooling tower.

[0007]

[0005] In conventional aftermarket coil assemblies, the energy transfer to the metal charge occurs through the electromagnetic field produced by the current flowing in the coil. These coils may have a square, round, or rectangular crosssection. However, square-sectioned coils are known to present several operational challenges, especially at higher furnace capacities. Increasing the induction voltage typically requires adding more coil windings, which is often constrained by the limited space between windings.

[0008]

[0006] The reduced spacing between successive coil turns in square-shaped designs leads to a higher risk of electrical sparking, increased induction losses, and diminished mechanical performance such as lower compressive strength and damping capacity. These limitations can significantly affect the stability and efficiency of high-capacity furnaces, making design optimization of coil assemblies critical to ensure reliable and effective furnace operation.

[0009]

[0007] Therefore, there exists a need for a coil assembly and an efficient high power capacity furnace with enhanced safety features and higher operational stability which address the aforementioned challenges.

[0010] OBJECT OF THE INVENTION:

[0011]

[0008] A principal objective of the present invention is to improve upon the conventional problems as described above, and to enhance electromagnetic efficiency of coreless induction furnaces by utilizing a trapezoidal cross-section coil trench, which improves magnetic coupling and reduces eddy current losses.

[0012]

[0009] Another objective of the invention is to reduce electrical sparking and improve safety by increasing the spacing between coil windings, enabled by the trapezoidal profile, and using high-voltage, high-temperature insulation materials between turns.

[0013]

[0010] Another objective of the invention is to improve thermal management and cooling efficiency by introducing stainless-steel cooling coils and leveraging water turbulence created by the trapezoidal coil cross-section, thereby enhancing heat dissipation and prolonging operational life.

[0014]

[0011] Another objective of the invention is to increase mechanical strength and structural integrity of the coil assembly through the use of FRP non-conductive support plates, monolithic refractory lining, and lamination packets, ensuring the coil remains stable under electromagnetic and thermal stresses.

[0015]

[0012] Another objective of the invention is to achieve higher energy efficiency by minimizing l2R losses with high-conductivity copper and optimized coil geometry, leading to reduced electricity consumption and faster melting cycles.

[0016]

[0013] Another objective of the invention is to provide scalability and adaptability of the coil assembly design for a wide range of furnace capacities, from 100 kg to 150 MT, addressing the needs of both current and future high-capacity melting operations. SUMMARY OF THE INVENTION

[0017]

[0014] The present invention provides a coil assembly. The coil assembly comprises a first ring assembly at a top portion of the coil assembly and a second ring assembly at a bottom portion of the coil assembly. The coil assembly comprises a coil member extending between the first ring assembly and the second ring assembly. The coil member comprises a trapezoidal cross-sectioned trench.

[0018]

[0015] The coil member is made up of high conductivity material. The coil member is supported by non-conducting plate arranged in between a monolithic refractory lining and a lamination assembly.

[0019]

[0016] In an embodiment, the lining former is sintered layer coated for providing a fine finish on the inner wall of the refractory lining.

[0020]

[0017] In an embodiment, the first ring assembly comprises a castable cement refractory on a top portion of an inner sider surrounded by a metallic shield. The second ring assembly comprises a castable cement refractory on a bottom portion of an inner sider surrounded by the metallic shield.

[0021]

[0018] In an embodiment, the trapezoidal cross-sectioned trench is wound helically such that the larger face of trapezoidal cross-sectioned trench arranged towards a refractory lining.

[0022]

[0019] In an embodiment, the blocks of non-conducting material are arranged in between a spacing / gap of successive trapezoidal cross-sectioned trench.

[0023]

[0020] In an embodiment, the coil assembly comprises non-conductive material sheets / plates that are fixed over the trapezoidal cross-section coil turns through fixtures.

[0024]

[0021] In an embodiment, the coil assembly comprises a plurality of lamination packets to provide the path to magnetic flux.

[0025]

[0022] In an embodiment, the coil assembly comprises a lining former on an inner wall of a refractory lining, a vertical channel assembly, and a lamination assembly. The lamination assembly is enclosed in the vertical channel assembly.

[0026] BRIEF DESCRIPTION OF THE DRAWINGS

[0027]

[0023] The present invention will hereinafter be described in conjunction with the accompanying drawings, wherein like numerals denote like elements. Additional embodiments of the invention will become evident upon reviewing the non-limiting embodiments described in the specification in conjunction with the accompanying drawings, wherein:

[0028]

[0024] Figure 1 illustrates a sectional view of a coil assembly, in accordance with an embodiment of the present invention.

[0029]

[0025] Figure 2 and Figure 3A illustrate an exploded view of the coil assembly with trapezoidal cross-sectioned coil assembly, in accordance with an embodiment of the present invention.

[0030]

[0026] Figure 3B illustrates an exploded view of the coil assembly with a staggering of trapezoidal cross-sectioned coil assembly, in accordance with an embodiment of the present invention.

[0031] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032]

[0027] Before presenting configuration of a vehicle, it is to be understood that this disclosure is not limited to particular assembly or configuration or arrangement for achieving as described, since it may vary within the specification indicated. It is further to be understood that the terminology used in the description is only for the purpose of describing the particular versions or embodiments and is not intended to limit the scope of the present invention.

[0033]

[0028] The words, “comprising”, “having”, “including” & “containing” and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items.

[0034]

[0029] The present invention discloses a design for a coil assembly with a trapezoidal or triangular cross-sectioned coil, preferably for electric furnaces and alternatively for metal forming processes such as heating, hardening, welding, brazing, etc. The coil assembly for an electric furnace comprises a helical trapezoidal or triangular coil assembly, a lining former, a monolithic refractory lining, a lamination assembly, a vertical channel assembly, a top ring assembly, and a bottom ring assembly.

[0035]

[0030] In an embodiment, the coil assembly comprises a trench with a trapezoidal or triangular cross-section made of high-conducting material, which is helically wound around a drum of the required diameter. This drum can rotate through the winding machine. Alternatively, a truncated-cone cross-section, triangular cross- section, or another similar cross-section may be employed. Furthermore, in this invention, copper is preferably utilized as the conducting material for the coil due to its very low resistivity, making it operationally cost-effective for the execution of the invention. However, other conducting materials can be alternatively used to achieve the same purpose.

[0036]

[0031] In an embodiment, during the helical winding of the trapezoidal or triangular cross-sectioned trench, the larger surface of the trapezoidal or triangular crosssectioned trench is preferably oriented towards the monolithic refractory lining. This orientation aims to decrease mutual induction loss. The arrangement of the trapezoidal or triangular cross-sectioned coil results in greater edge spacing or gaps between successive turns of the trapezoidal or triangular copper trench compared to the turns of a conventional rectangular copper trench, thereby reducing the risk of sparking. Each consecutive turn of the trapezoidal or triangular cross-sectioned coil is electrically insulated from one another using multiple layers of high-voltage and high-temperature abrasive-resistant polymer coating.

[0037]

[0032] The staggering of the trapezoidal or triangular cross-sectioned trench is executed to minimize dead space, thereby increasing the overall length. This configuration facilitates a more efficient and faster processing of the trapezoidal or triangular cross-sectioned trench, as the individual layers of the trench / strip can be more readily separated and accessed. Subsequently, the entire trapezoidal or triangular cross-sectioned assembly undergoes an annealing process to eliminate the spring effect present in the coil.

[0038]

[0033] In an embodiment, rectangular blocks of non-conducting material are strategically placed between the gaps of successive turns of the trapezoidal or triangular cross-sectioned trench. This arrangement serves to uphold the spacing between the coils, effectively mitigating the risk of sparking. The remaining space is then filled with monolithic refractory material during the preparation of the monolithic refractory lining. The complete filling of the space between the successive trench windings, using both non-conducting material blocks and monolithic refractory materials / linings, enhances the damping property and compressive strength of the Coil Assembly. Consequently, this results in a more robust and rigid coil assembly.

[0039]

[0034] In an alternative embodiment, the gaps between successive windings of the trapezoidal or triangular cross-sectioned trench can be entirely filled with non- conductive material blocks of a matching shape but positioned in reverse. This arrangement is further enveloped by the monolithic refractory lining.

[0040]

[0035] Moreover, to secure the entire trapezoidal or triangular cross-section coil turns / windings in place and prevent distortion, non-conductive material sheets / plates are affixed over the trapezoidal or triangular cross-section coil turns / windings using fixtures. In one embodiment, compressed mica is utilized as the non-conducting material for blocks or sheets; alternatively, other suitable materials can be employed to achieve the same purpose. Additionally, to prevent the flashover effect between the water-cooled trapezoidal or triangular crosssectioned copper coils / turns, these coils / turns are wrapped with polyester tap followed by varnishing / flexo coat insulation. Subsequently, the entire trapezoidal or triangular cross-sectioned coil assembly is coated with the required thickness. In the preferred embodiment, a flexo coat insulation of 5KV / 0.4 mm thickness is applied; however, the thickness range can be varied based on the selected coating material.

[0041]

[0036] The entire coil assembly is enveloped by multiple lamination packets to facilitate the path for magnetic flux, arranged within the lamination assembly. Ideally, these lamination packets are constructed from Cold Rolled Grain Oriented (CRGO) steel sheets. Alternatively, other suitable materials can be utilized to achieve the same objective. The quantity of lamination packets / sheets can be determined based on the furnace's capacity.

[0042]

[0037] The trapezoidal cross-section of the coil assembly induces water turbulence, leading to improved heat transfer compared to a rectangular crosssectioned coil assembly. These all above consideration results in the enhancement of efficiency of melting furnace, that reduces the batch cycle time leads to the increase in rate of production. These increase in productivity reduces the unit consumption result in monitory profit. The novel design of the coil assembly with a trapezoidal or triangular cross-sectioned coil, as presented in this invention, yields an improvement in electrical efficiency by reducing I2R losses and enhances thermal efficiency by minimizing conduction heat losses. Additionally, it mitigates electrical sparking, boosts compressive strength, and augments damping properties, rendering the coil assembly more rigid. These enhanced characteristics prove valuable in the design and development of higher batch capacity furnaces, ranging from 100 kgs to 150 MT and potentially exceeding these capacities in the near future.

[0043]

[0038] Figure 1 illustrates a sectional view of a coil assembly, in accordance with an embodiment of the present invention. The coil assembly described in herein is a crucial component of a coreless induction furnace, and it has been designed to address some of the inherent challenges in conventional coil configurations, especially for high-capacity melting operations. The coil assembly described herein comprises several integrated components working together to improve energy transfer, mechanical stability, and thermal management during furnace operation.

[0039] Referring to Figure 1 , the coil assembly (100) comprises a first ring assembly (102) at a top portion of the coil assembly (100). The coil assembly (100) further comprises a second ring assembly (1 16) at a bottom portion of the coil assembly (100). These ring assemblies (102, 116) serve both structural and functional purposes. They help in securing the coil assembly in a fixed position vertically and also house critical elements such as cooling systems and insulation components. These assemblies are clamped securely to provide rigidity and stability to the entire structure.

[0044]

[0040] The coil assembly (100) further comprises a coil member (1 12) extending between the first ring assembly (102) and the second ring assembly (1 16). The coil member (112, (200 in Figure 2) extends vertically between the two ring assemblies and acts as the principal inductor. The coil member (112) is responsible for generating the electromagnetic field required to induce currents in the metal charge placed within the furnace. Unlike traditional designs that often employ square or round cross-sections, this embodiment uses a trapezoidal-shaped coil (explained in Figure 2), which helps optimize spacing between windings, reduce the risk of sparking, and enhance electromagnetic coupling efficiency. The coil member (112) is fabricated from a high-conductivity material, typically copper, to minimize resistive losses and maximize current-carrying capacity. Between the coil and other furnace components, non-conducting support plates are inserted. These insulating plates ensure electrical isolation while offering mechanical support, thus preventing short circuits and enhancing the durability of the structure under thermal stress.

[0045]

[0041] The coil assembly (100) further includes a lining former (104), a lining refractory (106), lamination assembly (108), and a vertical channel assembly (120). Encasing the inner side of the coil is the lining former (104), which is an inner mold or surface designed to support the formation of the monolithic refractory lining (106). The lining former (104) is coated with a sintered layer, which provides a smooth and thermally resistant finish to the inner wall of the refractory lining. This refractory lining serves to contain the molten metal while protecting the induction coil from the intense heat generated during melting.

[0046]

[0042] In the sequential radial arrangement of components of coil assembly (100). The coil member (1 12) is made up of high conductivity material that is supported by non-conducting plate arranged in between the monolithic refractory lining (106) and the lamination assembly (108). The lamination assembly (108) likely consists of stacked ferromagnetic laminations that help to direct and contain the magnetic flux generated by the coil. This reduces eddy current losses in surrounding metallic structures and enhances the overall efficiency of magnetic coupling between the coil and the charge. The lining former (104) is sintered layer coated for providing fine finish on inner wall of the refractory lining (106). The lamination assembly (108) is enclosed in the vertical channel assembly (120). The vertical channel assembly (120) is made up of mild steel.

[0047]

[0043] Further, the coil assembly (100) vertically clamp with the first ring assembly (102) and the second ring assembly (1 16). The first ring assembly (102) comprises a castable cement refractory (1 14) on a top portion of an inner sider surrounded by a metallic shield. Similarly, the second ring assembly (102) comprises a castable cement refractory (1 18) on a bottom portion of an inner sider surrounded by the metallic shield.

[0048]

[0044] In an embodiment, the coil assembly (100) comprises a ground leak detector (110) is arranged at the center of coil assembly (100). ground leak detector (110) is essential for safety and monitoring, as it detects any unintended electrical contact or leakage between the live coil and grounded furnace parts. If such leakage occurs, the detector can trigger safety protocols to prevent damage or hazard.

[0049]

[0045] In an embodiment, the stainless-steel cooling coil of circular cross section (not shown in figure) are attached at the top and bottom of the trapezoidal coil member (1 12) within the first ring Assembly (102) and the second ring assembly (116). However, alternatively cooling coil of other material and cross section can be used to serve the purpose of cooling.

[0046] Figure 2 and Figure 3A illustrate an exploded view of a trapezoidal crosssectioned coil assembly, in accordance with an embodiment of the present invention. In an embodiment, the coil member (200) (referred as 1 12 which is shown in Figure 1 ) comprises trapezoidal cross-sectioned trench (202). The trapezoidal cross-sectioned trench (202) is made up of high conducting material and is helically wound on the drum (not shown in figure) of required diameter, that can rotate through the winding machine.

[0050]

[0047] In another embodiment, truncated-cone cross-sectioned or triangular cross-section or other similar cross section can be used as coil trench (202). Further, preferably copper is used as conducting material for coil trench (202) due to very low resistivity for operational at competitive cost for execution of the invention. However alternatively other conducting material can be used to serve the same purpose.

[0051]

[0048] In an embodiment, the trapezoidal cross-sectioned trench (202) is wound helically such that the larger face of trapezoidal cross-sectioned trench is arranged towards the monolithic refractory lining (204) to reduce the mutual induction loss. This arrangement of trapezoidal cross-sectioned coil (202) provides more edge spacing or gap (206) between the successive turns of trapezoidal copper trench (202) compared with the successive turns of conventional rectangular copper trench that reduces the risk of sparking. Each successive trapezoidal crosssectioned coil (202) turns are electrically insulated from each other using several layers of high voltage and high temperature abrasive resistant polymer coating.

[0052]

[0049] Figure 3B illustrates an exploded view of the coil assembly with a staggering of trapezoidal cross-sectioned coil member, in accordance with an embodiment of the present invention Further, staggering of trapezoidal crosssectioned trench (202) is implemented to reduce dead space, which provides greater length, allows easier and faster processing of the trapezoidal crosssectioned trench (202), as the individual layers of the trench / strip can be more easily separated and accessed. Then, complete of trapezoidal cross-sectioned assembly [Refer Figure 3A] is subjected to annealing process to remove the spring effect in the coil (202).

[0053]

[0050] In an embodiment, blocks of non-conducting material (206) preferably rectangular shape are arranged in between the spacing / gap of successive trapezoidal cross-sectioned trench (202) turn to maintain the spacing between the coils which further nullifies the sparking risk. The remaining space filled with the monolithic refractory material (not shown in figure) during the preparation of monolithic refractory lining (204). The space between the successive trench winding (202), complete filling up of using the non-conducting material blocks (206) and monolithic refractory materials (not shown in figure) provide the enhance the damping property and compressive strength of coil assembly (100, 200), this results into the rigid coil assembly (200).

[0054]

[0051] In another embodiment, the spacing / gap of successive trapezoidal crosssectioned trench winding can be completely filled up with the non-conductive material block of replicate shape in reverse position, that can further surround by the monolithic refractory lining. These insulation layers must withstand the dual stresses of thermal cycling and electromagnetic forces over long periods. The use of such advanced polymers ensures that the insulation remains intact, even in the harsh operational conditions typical of induction furnaces.

[0055]

[0052] Further, to hold the complete trapezoidal cross-section coil (202) turns / windings in position and prevent the distortion, the non-conductive material sheets / plates (208) are fixed over the trapezoidal cross-section coil turns / windings (202) through fixtures. In an embodiment, the non-conducting material for block or sheet (208) used is Fiber Reinforced Plastic (FRP), alternatively other suitable material can be used the serve the same purpose. The trapezoidal shape of the trench offers another significant advantage wider edge spacing or gap between successive turns of the coil compared to conventional rectangular trenches. This larger spacing helps reduce the risk of electrical sparking, which is a common issue in high-frequency, high-current induction furnaces. Sparks can not only damage the coil but also pose serious safety risks. The trapezoidal profile, by virtue of its shape, naturally tapers away from the adjacent coil turn, allowing more air or insulating space.

[0056]

[0053] In addition to this, to avoid the flash over effect between the water-cooled trapezoidal cross-sectioned copper coils / turns (202), those coils / turns wounded with mica sheet followed by varnishing. Finally, complete trapezoidal crosssectioned coil assembly [refer Figure 3A] is coated with required thickness. In preferred embodiment, the flex coat insulation 5KV / 0.4 mm thickness is done, alternatively thickness range can be varied based the other selected coating material.

[0054] The coil member (1 12, 200) is further surrounded by a number of lamination packets (210) to provide the path to the magnetic flux. The number of lamination packets (210) are arranged with a lamination assembly (212). Preferably, the lamination packets (210) made up of Cold Rolled Grain Oriented (CRGO) steel sheet. Alternatively, other suitable material can be used to serve the same purpose. Further, number of lamination packets / sheets (210) can be considered depends on the capacity of the furnace.

[0057]

[0055] The trapezoidal cross-sectioned of coil turns (202) results in the water turbulence which provides the better heat transfer compared to the rectangular cross-sectioned coil assembly. These all above consideration results in the enhancement of efficiency of melting furnace, that reduces the batch cycle time leads to the increase in rate of production. These increase in productivity reduces the unit consumption result in monitory profit.

[0058]

[0056] The present invention of novel design of coil assembly with the trapezoidal cross-sectioned coil results in enhancement of electrical efficiency with reduction in I2R losses, thermal efficiency with lower conduction heat losses, avoids electrical sparking, enhance compressive strength and damping property that makes the coil assembly more rigid. It is applicable for 100 kgs to 40 MT in existing design as well as for the design and development of higher batch capacity furnace ranging from 40 MT to 150 MT and more in near future.

[0059]

[0057] This trapezoidal trench-based design not only improves electromagnetic efficiency and electrical safety, but also enhances mechanical stability. The wider base of the trapezoid facing the charge creates a more stable and structurally sound winding pattern. The coil remains securely in place under the influence of electromagnetic forces, vibrations, and thermal expansion.

[0060]

[0058] The invention provides a structurally optimized and electromagnetically efficient coil design for induction furnaces using a trapezoidal trench made of high- conductivity material, preferably copper. Its helical winding pattern, increased interturn spacing, strategic orientation toward the refractory lining, and robust insulation system work together to enhance furnace performance, safety, and durability. This design represents a significant improvement over traditional square or rectangular coil designs, especially in applications demanding higher thermal loads, greater electromagnetic efficiency, and longer operational life cycles.

[0059] The fact that the coil can be wound helically on a rotating drum offers customizability in coil geometry, enabling manufacturers to tailor the coil dimensions, winding pitch, and spacing for different furnace capacities and applications. This modular and scalable manufacturing process supports both small and large-scale furnace installations.

[0061]

[0060] Technical advantages of the invention:

[0062] • Improved Electromagnetic Efficiency & Reduced l2R Losses: The trapezoidal shape, when oriented with the larger face toward the refractory lining, enhances magnetic coupling with the molten metal charge, resulting in more effective energy transfer. This orientation, combined with high-conductivity materials (e.g., copper), leads to reduced electrical resistance and l2R losses, thereby increasing electrical efficiency.

[0063] • Enhanced Thermal Performance via Water Turbulence: The trapezoidal coil geometry promotes turbulent water flow inside the coil, which significantly improves heat transfer efficiency. Better cooling helps maintain coil temperature within safe operational limits, leading to lower thermal conduction losses and extending the lifespan of the coil assembly.

[0064] • Reduced Sparking Risk Due to Larger Inter-Turn Gaps: The naturally wider spacing between successive trapezoidal turns, compared to conventional rectangular coils, minimizes the risk of arcing or electrical sparking, which is critical for safety, especially in high-frequency, high- current induction furnaces.

[0065] • Improved Mechanical Stability and Structural Rigidity: The trapezoidal shape, in conjunction with non-conducting support plates (e.g., FRP) and filling with refractory material, enhances compressive strength and damping properties. This makes the coil assembly highly rigid and vibration-resistant, ensuring dimensional stability under mechanical and thermal stresses.

[0066] • Enhanced Insulation and Electrical Safety: Each coil turn is insulated using high-voltage, high-temperature, and abrasion-resistant polymer coatings, along with mica wrapping and varnishing. This robust multi- layer insulation system improves dielectric strength and prevents electrical breakdown, even under prolonged high-load operations.

[0067] • Modular and Scalable Design: The helical winding of the trapezoidal trench on a rotating drum allows for customization in coil pitch, diameter, and configuration, making the design easily scalable from 100 kg up to 150 MT furnace capacities. This modularity enables manufacturers to adapt the coil design across a broad range of furnace sizes.

[0068] • Reduced Dead Space and Faster Coil Processing: The staggering of coil windings and potential use of reverse-shaped filler blocks help reduce dead space and allow faster, more accessible coil fabrication and inspection. This also contributes to a denser, more efficient coil structure.

[0069]

[0061] Although the subject matter has been described in language specific to structural features and / or methods in considerable detail with reference to certain preferred embodiments thereof, it is to be understood that the implementations and / or embodiments are not necessarily limited to the specific features or methods described. The examples described in detail here are only some possible embodiments of the invention among others and it could be subjected to many alterations and variants within the grasp of those skilled in the art. As such, the spirit and scope of the appended

[0070] Dated this 25 May 2024

Claims

WE CLAIM:1 . A coil assembly (100, 200), comprising: a first ring assembly (102) at a top portion of the coil assembly (100); a second ring assembly (116) at a bottom portion of the coil assembly (100); a coil member (112, 200) extending between the first ring assembly (102) and the second ring assembly (116), wherein the coil member (116, 200) comprises a trapezoidal cross-sectioned trench (202).

2. The coil assembly (100, 200) as claimed in claim 1 , wherein the coil member (112) is made up of high conductivity material, wherein the coil member (1 12) is supported by non-conducting plate arranged in between a monolithic refractory lining (106, 204) and a lamination assembly (108).

3. The coil assembly (100, 200) as claimed in claim 1 , wherein the lining former (104) is sintered layer coated for providing a fine finish on the inner wall of the refractory lining (106).

4. The coil assembly (100, 200) as claimed in claim 1 , wherein the first ring assembly (102) comprises a castable cement refractory (1 14) on a top portion of an inner sider surrounded by a metallic shield, wherein the second ring assembly (102) comprises a castable cement refractory (1 18) on a bottom portion of an inner sider surrounded by the metallic shield.

5. The coil assembly as claimed in claim 1 , wherein the trapezoidal cross-sectioned trench (202) is wound helically such that the larger face of trapezoidal crosssectioned trench arranged towards a refractory lining (106, 204).

6. The coil assembly as claimed in claim 1 , wherein the blocks of non-conducting material (206) are arranged in between a spacing / gap of successive trapezoidal cross-sectioned trench (202).

7. The coil assembly as claimed in claim 1 , comprising non-conductive material sheets / plates (208) that are fixed over the trapezoidal cross-section coil turns (202) through fixtures.

8. The coil assembly as claimed in claim 1 , comprising a plurality of lamination packets (210) to provide the path to magnetic flux.

9. The coil assembly as claimed in claim 1 , comprising: a lining former (104) on an inner wall of a refractory lining (106); a vertical channel assembly (120); a lamination assembly (108), wherein the lamination assembly (108) is enclosed in the vertical channel assembly (120).

10. The coil assembly as claimed in claim 1 , wherein the coil member (112, 200) is surrounded by a plurality of lamination packets (210) to provide a path to the magnetic flux, wherein the plurality of lamination packets (210) are arranged with a lamination assembly (212).Dated this 25 May 2024

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