WO2025248549A1

WO2025248549A1 - Off-load isolator system with busbar assembly for melting furnaces

Info

Publication number: WO2025248549A1
Application number: PCT/IN2025/050789
Authority: WO
Inventors: Shailesh Bhanwarlal BHANDARI; Suraj Shailesh BHANDARI
Original assignee: Individual
Current assignee: Individual
Priority date: 2024-05-25
Filing date: 2025-05-24
Publication date: 2025-12-04
Anticipated expiration: 2026-11-25

Abstract

Embodiments of the present invention disclose an Off-load Isolator System with Busbar Assembly (100) for electric melting furnaces (106), designed to replace conventional water-cooled current- carrying cables. The system includes a busbar assembly (102) having hollow, liquid-cooled coil-extended busbars (202) and outgoing busbars (208), connected respectively to the fixed assembly (400) and movable assembly (500) of an Off¬ load Isolator System (104). An actuation system (306) with a cam-operated wedge guide mechanism (308) enables linear engagement and disengagement between assemblies. The fixed assembly (400) and movable assembly (500) include high-conductivity metallic sheets (402, 508) with silver contact strips (410, 512) for high-current transfer. Spring- loaded fixture rods (602, 610, 612) and limit switches (620-626) ensure precise control and safety. The system provides reduced power loss, minimal water usage, compactness, and low maintenance, offering a reliable and efficient alternative to traditional systems.

Description

"OFF-LOAD ISOLATOR SYSTEM WITH BUSBAR ASSEMBLY FOR MELTING FURNACES"

FIELD OF INVENTION

[001] The embodiments of present disclosure are in general related to a melting furnace, preferably electric melting furnace. Particularly it relates to a system for replacing water-cooled current carrying cables (WCCs) with an Offload Isolator System with Busbar Assembly to improve efficiency, reliability, and ease of maintenance in induction furnace operations.

BACKGROUND

Interpretation Considerations

[002] The section describes the background of the technical field for understanding the problems encountered in the technical field.

Discussion

[003] Electric induction furnaces are widely used for melting various metals and alloys due to their high energy efficiency, precise control and economic significance with large-scale catering of metallurgical requirements.

[004] The traditional induction furnaces employ water-cooled current carrying cables (WCCs) to deliver high current to the furnace coil. However, WCCs have several drawbacks/limitations such as high-power (1²R) losses, large cooling water requirement, insulation issues, leakage issues, bulky setup, more space required, Hose Bending limitation, frequent hose failure, frequent generation of mechanical and thermal stresses, electrical damages in WCCs and other connected parts of furnace, frequent maintenance and cleaning and high operating cost.

[005] The present invention addresses these challenges by replacing WCCs with an Off-load Isolator System with Busbar Assembly that simplifies the electrical connections, reduces power losses, and improves operational efficiency.

SUMMARY

[006] The present invention relates to an Off-load Isolator System with Busbar Assembly for melting furnace comprising a busbar assembly, an off-load isolator system and an actuation system. Here the busbar assembly comprising a set of coil-extended busbars and a set of outgoing busbars. Further the offload isolator system comprises a fixed assembly and a movable assembly. The actuation system is configured to move the movable assembly linearly with respect to the fixed assembly through a cam-operated wedge guide mechanism. Here the actuation system is selected from pneumatic actuation system, hydraulic actuation system, electric actuation system, automatic actuation system, manual actuation system, mechanical actuation system and a combinations thereof, specifically the actuation system is pneumatic actuation system. The pneumatic actuation system is integral with off-load isolator system that connected with busbar assembly

[007] In one embodiment, the present invention relates to the Off-load Isolator System with Busbar Assembly is particularly developed for use in electric melting furnaces, and also adaptable to other metal forming operations such as hardening, heating, welding, brazing, and similar industrial applications. The invention is aimed at replacing traditional water-cooled current- carrying cables with a more efficient, modular, and safer solution.

[008] In an embodiment, the invention of the Off-load Isolator System with Busbar Assembly comprises a Busbar Assembly, an Off-load Isolator System and an actuation system. The Busbar Assembly includes a set of hollow, liquid- cooled busbars — specifically, coil-extended busbars and outgoing busbars. One end of the coil-extended busbars connects to the fixed assembly, while the other connects to the furnace coil extensions. Similarly, the outgoing busbars connect at one end to the movable assembly and at the other end to a manifold located on the cap rack. These hollow busbars are cooled using distilled water or other suitable liquid coolant to minimize resistive losses and maintain thermal efficiency.

[009] The Off-load Isolator System features a fixed assembly and a movable assembly, which are operated through an actuation system integrated with a wedge-guided cam mechanism. A pneumatic actuation system is preferred, alternatively hydraulic, electric or automatic or manual systems or combinations thereof may be employed. The fixed assembly comprises a set of high-conductive metallic sheets (Set A), preferably made of copper, spaced using non-conductive materials. The lower section of Set A includes silver- b razed contact strips to ensure efficient high-current conduction. The metallic sheets also incorporate water inlet and outlet provisions to facilitate cooling.

[010] The movable assembly consists of three non-conductive sheets arranged in sequence, with the middle sheet being thicker to match the spacing of the fixed assembly's metallic sheets. Attached to these non-conductive sheets are two sets of metallic sheets-Set B and Set C. Set B mimics the structure of Set A and is mounted on the inner surfaces of the outer non-conductive sheets. It also includes silver contact strips to establish electrical contact with Set A. On the other hand, Set C is mounted on the middle non-conductive sheet and is designed for connection to the liquid-cooled outgoing busbars, featuring appropriate ports for coolant circulation.

[Oil] The movable assembly is guided and supported by a central helical and disc spring-loaded fixture rod, along with two side helical spring fixture rods, all aligned in the same plane. These rods assist in controlling the movement of the assembly and help in maintaining correct contact positions. The actuation of the movable assembly is achieved through the wedge-guided cam mechanism driven by the pneumatic system. During operation, this mechanism enables the linear movement of Set B metallic sheets into and out of contact with Set A sheets in the fixed assembly. [012] Additionally, limit switches are mounted on the external corners of the movable assembly to indicate the connection status (ON/OFF) of the system. The invention features two configurations; Closed Configuration, where the fixed and movable assemblies are in contact, allowing high-density current to flow for melting operations; and Open Configuration, where the assemblies are disconnected, ensuring electrical isolation during operations such as metal pouring.

[013] The systems of disclosed invention designed for customization and adaptability, allowing changes in material, shape, and configuration of components like metallic sheets, non-conductive layers, and busbars to meet specific industrial requirements. This invention offers significant advantages in terms of electrical efficiency, thermal management, safety, and operational flexibility, presenting a robust alternative to traditional current supply methods in induction furnaces and other high-power applications.

[014] In another embodiment, the Off-load Isolator System with Busbar Assembly comprises coil-extended busbars being configured to be engaged at one end to the fixed assembly and at another end to coil extensions of the furnace. The outgoing busbars of the Off-load Isolator System with Busbar Assembly are connected at one end to the movable assembly and at the other end to a manifold on a cap rack.

[015] In another embodiment, the Off-load Isolator System with Busbar Assembly having fixed assembly comprises a plurality of high-conductive metallic sheets (Set A) arranged with a fixed gap using non-conductive blocks and a squared silver contact strips brazed to the bottom of the outer surface of said metallic sheets and vertical perforations on the lower portion of said metallic sheets, coil-extension busbar mounting means on the upper portion; and inlet and outlet ports for liquid cooling.

[016] The movable assembly of the Off-load Isolator System with Busbar Assembly comprises three non-conductive sheets arranged consecutively, with the middle sheet having greater thickness than the outer two; a first set of metallic sheets (Set B] mounted on the inner surfaces of the outer sheets; a second set of metallic sheets (Set C] mounted on the outer surface of the middle sheet; inlet and outlet extensions for water cooling in both sets of metallic sheets; and silver contact strips razed on Set B to ensure high current transfer. The set B is a replica of Set A of the fixed assembly and the set C is vertically rectangular and includes connection ports for outgoing busbars. Here movable assembly further comprises a spring-loaded fixture rod system. The spring-loaded fixture further comprises a central helical and disc spring- loaded rod arranged through the center of the three non-conductive sheets on two helical spring fixture rods on either side of the central rod in the same plane. The spring rods facilitate linear movement and positioning of the movable assembly. The wedge-guided cam mechanism assists in the connection of spring-loaded fixture rod system is operably connected to an actuator. The spring-loaded fixture rod system is operably connected to an actuator through a wedge-guided cam mechanism. Here the actuation system is adapted to actuate the movable assembly to achieve Open and Close configurations by engagement or disengagement with the fixed assembly. The Off-load Isolator System with Busbar Assembly further comprising limit switches mounted at the corners of the movable assembly’s outer non- conductive sheets to indicate ON/OFF or Close/Open status. The Close Configuration the fixed assembly and movable assembly are electrically and mechanically connected; and current flows through the contact strips and busbar assembly to enable operation. The open Configuration is the fixed and movable assembly are disconnected; and no current transformation occurs, enabling molten metal pouring. The Off-load Isolator System with Busbar Assembly mechanism is configured to be compact, low-maintenance, spacesaving, and more energy-efficient compared to conventional water-cooled current- carrying cable systems.

BRIEF DESCRIPTION OF DRAWINGS [017] The accompanying drawings, incorporated in the present disclosure and constituting a part of the same, illustrate the exemplary embodiments. The drawings, together with the description, serve to explain the disclosed principles. Some embodiments of the present subject matter are now described by way of example only and with reference to the accompanying figure, in that:

[018] Figure 1 illustrates a Melting Furnace with Off-load Isolator System with Busbar Assembly in accordance with some embodiments of the present disclosure; and

[019] Figure 2 illustrates an Off-load Isolator system with Busbar Assembly in accordance with some embodiments of the present disclosure; and

[020] Figure 3 illustrates an Off-load Isolator system in accordance with some embodiments of the present disclosure; and

[021] Figure 4 illustrates a Fixed Assembly of Off-load Isolator System in accordance with some embodiments of the present disclosure; and

[022] Figure 5 illustrates a Movable assembly of Off-load Isolator System in accordance with some embodiments of the present disclosure; and

[023] Figure 6 illustrates a sectional view of Off-load Isolator System in accordance with some embodiments of the present disclosure; and

[024] Figure 7 illustrates a Close Configuration and Open Configuration of Offload Isolator System in accordance with some embodiments of the present disclosure; and

DETAILED DESCRIPTION OF DRAWINGS

[025] In the present disclosure, the word "exemplary" is used herein to mean as an example, instance, or illustration. Any embodiment or implementation of the present subject matter described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. [026] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in drawings and will be described in detail below. However, it should be understood that it is not intended to limit the disclosure to the particular form disclosed; on the contrary, the disclosure is intended to cover all modifications, equivalents, and alternatives falling within the spirit and the scope of the disclosure.

[027] The terms "comprises," "comprising," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a setup, device, or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such a setup or device or method. In other words, one or more elements in a device or system or apparatus preceded by "comprises... a" does not, without more, constrain the system or apparatus.

[028] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof and that are shown by way of illustration of specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized, and changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

[029] The detailed description of the figures provides a better comprehension of the present invention.

[030] Figure 1 is an exemplary illustration of the Melting Furnace with Offload Isolator System with Busbar Assembly (100).

[031] The Melting Furnace with Off-load Isolator System with Busbar Assembly (100) comprising the Busbar Assembly (102), connects the electric melting furnace (106) to the cap rack (110), the Off-load Isolator System (104), the Actuation system (112). This system serves as a superior replacement for conventional water-cooled current- carrying cables, offering benefits such as reduced power loss due to shorter current paths, lower cooling requirements, reduced maintenance, simplified assembly, and compact installation.

[032] Figure 2 is an exemplary illustration of Off-load Isolator system with Busbar Assembly (200)

[033] The system comprises liquid-cooled hollow busbars, including a set of coil-extended busbars (202) and a set of outgoing busbars (208). One end of the coil-extended busbars is connected to the fixed assembly (206), while the other connects to the furnace coil extensions (204). Similarly, one end of the outgoing busbars (208) connects to the movable assembly (210), with the other connected to the manifold on the cap rack (212). These rectangular hollow busbars are made of copper for high conductivity and economic efficiency. Other materials and shapes known in the art may alternatively be used.

[034] Figure 3 is an exemplary illustration of an Off-load Isolator system (300).

[035] The Off-load Isolator System (300) comprising the fixed assembly (302) and the movable assembly (304), which is actuated by a pneumatic system (306) through a wedge-guided cam mechanism (308). The system operates in two configurations — open and close — controlled by the engagement or disengagement of the fixed and movable assemblies, thus enabling different operational modes of the furnace. The pneumatic actuation system (306) is preferred, alternatively hydraulic, electric or automatic or manual systems or combinations thereof may be employed.

[036] Figure 4 is an exemplary illustration of fixed assembly of Off-load

Isolator System (400) [037] The fixed assembly includes a set of high-conductivity metallic sheets (Set A, 402), preferably copper, arranged with specific spacing using non- conductive blocks (404). These sheets are square or four-edged in shape and are fixed at the top to the coil-extension busbar using metallic bolts (406). Vertical perforations (408) on the lower side of Set A facilitate flexible contact, while silver contact strips (410) brazed at the bottom enhance current transfer. Water inlet and outlet extensions (412) are provided at the top. In this embodiment, the non-conductive spacers are made of fiber-reinforced plastic (FRP), although alternative materials and geometries may be employed.

[038] Figure 5 is an exemplary illustration of Movable assembly of Off-load Isolator System (500)

[039] The movable assembly (500) comprises three consecutively arranged non-conductive sheets (502, 504, and 506), with the middle sheet (506) being thicker to match the spacing of the metallic sheets in the fixed assembly. Two sets of metallic sheets, Set B (508) and Set C (510), are arranged on these sheets. Set B (508) mirrors Set A and is affixed to the inner surfaces of the first and third non-conductive sheets, while Set C (510), vertically rectangular in shape, is fixed to the outer surface of the middle sheet using fasteners (520). Silver contact strips (512) are brazed to Set B (508) for contact with Set A. Provisions for water inlet and outlet (518) are included and Set C (510) includes connection points (522) for the outgoing busbars. Alternative arrangements and materials for these components may be utilized as required.

[040] Figure 6 is an exemplary illustration of sectional view of Off-load Isolator System (600)

[041] In an Off-load Isolator system (600), showing the internal actuation mechanism of the movable assembly. A central helical disc spring-loaded fixture rod (602) passes through the three non-conductive sheets (604, 606, and 608), enabling linear motion. Two additional helical spring rods (610 and 612) are placed on either side in the same plane to limit movement and assist in precise alignment of the contacting metallic sheets, Set B (614). The central fixture rod (602) is connected to the pneumatic system (616) via a cam- operated wedge guide mechanism (618). As the movable assembly translates, Set B moves in and out accordingly. Limit switches (620, 622, 624, and 626) are mounted on the corners of the outer surfaces of the first and third sheets to indicate the ON/OFF status of the system.

[042] Figure 7 is an exemplary illustration of Close Configuration (700A) and Open Configuration (700B) of Off-load Isolator System.

[043] The present invention discloses the two operating configurations of the Off-load Isolator System: Close Configuration (700A) and the Open Configuration (700B). In the Close Configuration, the fixed assembly (702A) and movable assembly (706A), actuated by the pneumatic system and wedge- guided cam mechanism (704A), are electrically connected, allowing high- density current to flow and enable the melting operation — thereby completing the circuit loop. In the Open Configuration, the fixed assembly (702B) and movable assembly (706B) are disengaged via the pneumatic system and cam mechanism (704B), halting current flow and facilitating safe molten metal pouring operations by opening the circuit loop.

Claims

We Claim:

1. An Off-load Isolator System with Busbar Assembly (100) for melting furnaces (106) comprising: a busbar assembly (102); an off-load isolator system (104); and an actuation system (112).

2. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said busbar assembly (102) comprising a set of coil-extended busbars (202) and a set of outgoing busbars (208).

3. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said off-load isolator system (104) comprising a fixed assembly (400) and a movable assembly (500).

4. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said actuation system (112) configured to move the movable assembly linearly with respect to the fixed assembly (400) through a cam- operated wedge guide mechanism (308, 618).

5. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said actuation system (112) is selected from pneumatic actuation system, hydraulic actuation system, electric actuation system, automatic actuation system, manual actuation system, mechanical actuation system and a combination thereof.

6. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said actuation system (112) is integral with off-load isolator system (104) that connected with busbar assembly (102).

7. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said busbars (102, 202, 208) are hollow, liquid-cooled and of high- conductive metal.

8. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said coil-extended busbars (202) are connected at one end to the fixed assembly (400) and at another end to coil extensions (204) of the furnace.

9. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said outgoing busbars (208) are connected at one end to the movable assembly (500) and at the other end to a manifold on a cap rack [212).

10. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein the fixed assembly (400) comprises: a plurality of high-conductive metallic sheets (Set A) (402) arranged with a fixed gap using non-conductive blocks (404); squared silver contact strips (410) brazed to the bottom of the outer surface of said metallic sheets; vertical perforations (408) on the lower portion of said metallic sheets; coil-extension busbar mounting means (406) on the upper portion; and inlet and outlet ports (414, 416) for liquid cooling.

11. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said movable assembly (500) comprises: three non-conductive sheets (502, 504, 506) arranged consecutively, with the middle sheet (506) having greater thickness than the outer two; a first set of metallic sheets (Set B) (508) mounted on the inner surfaces of the outer sheets; a second set of metallic sheets (Set C) (510) mounted on the outer surface of the middle sheet; inlet and outlet (516, 518) extensions for water cooling in both sets of metallic sheets; and silver contact strips (512) brazed on Set B (508) to ensure high current transfer.

12. The Off-load Isolator System with Busbar Assembly as claimed in claim

11, wherein said Set B (508) is a replica of Set A (402) of the fixed assembly.

13. The Off-load Isolator System with Busbar Assembly as claimed in claim 11, wherein said Set C (510) is vertically rectangular and includes connection ports (522) for outgoing busbars (208).

14. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein said movable assembly (500) further comprises a spring-loaded fixture rod system (600) comprising: a central helical and disc spring-loaded rod (602) arranged through the center of the three non-conductive sheets; two helical spring fixture rods (610, 612) on either side of the central rod in the same plane; wherein the spring rods facilitate linear movement and positioning of the movable assembly.

15. The Off-load Isolator System with Busbar Assembly as claimed in claim 14, wherein said spring-loaded fixture rod system (600) is operably connected to an actuator (306) through a wedge-guided cam mechanism (308, 618).

16. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein the actuation system (112) is adapted to actuate the movable assembly (500) to achieve Open (700A) and Close (700B) configurations by engagement or disengagement with the fixed assembly (400).

17. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, further comprising limit switches (620, 622, 624, 626) mounted at the corners of the movable assembly’s outer non-conductive sheets (502, 504) to indicate ON/OFF or Close/Open status.

18. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein in the Close Configuration (700A): the fixed assembly (400) and movable assembly (500) are electrically and mechanically connected; and current flows through the contact strips (410, 512) and busbar assembly (102) to enable operation.

19. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein in the Open Configuration (700B): the fixed (400) and movable assembly (500) are disconnected; and no current transformation occurs, enabling molten metal pouring.

20. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein the Off-load Isolator System with Busbar Assembly mechanism is configured to be compact, low-maintenance, space-saving, and more energyefficient compared to conventional water-cooled current- carrying cable systems.

21. The Off-load Isolator System with Busbar Assembly as claimed in claim 1, wherein the material, shape, or arrangement of the metallic and non-metallic components can be varied without departing from the scope of the invention to adapt to different furnace or operational requirements.

22. The Off-load Isolator System with Busbar Assembly as claimed in claim 1 is preferably employed for electric melting furnaces alternatively employed to electric arc furnace, metal forming operations such as hardening, heating, welding, brazing, and similar industrial applications.