A high gradient vertical ring magnetic separator exciting coil

Abstract

The application relates to the technical field of magnetic separators, in particular to a high-gradient vertical-ring magnetic separator excitation coil, which comprises a coil body and a terminal box, the coil body is composed of a plurality of independent pie-shaped coils which are stacked and combined along the axial direction, the first end and the last end of each pie-shaped coil are provided with a terminal head, the terminal box is provided with terminal posts which are matched with the terminal heads one by one, each terminal head is electrically connected with a terminal post through an external wire one by one, and each terminal post is electrically connected with the switchable connecting member, so that the adjustable control of the number of loop access and the series-parallel combination mode of the pie-shaped coils is realized. The independent pie-shaped coils are axially stacked to form the coil body, the partition type terminal structure in the terminal box and the switchable connecting member are matched, the number of loop access and the series-parallel combination mode of the pie-shaped coils can be flexibly adjusted, the voltage regulation and current limiting of external power supply equipment are not needed, and the working current and the magnetic field intensity can be accurately controlled from the structure level of the coil body.

Description

Technical Field

[0001] This invention relates to the field of magnetic separator technology, specifically to an excitation coil for a high-gradient vertical ring magnetic separator. Background Technology

[0002] The vertical ring high gradient magnetic separator is one of the core devices for wet separation of weakly magnetic minerals and purification of non-metallic minerals. Its working principle is to use the background magnetic field generated by the magnetic field loop space formed by the excitation coil in the gap between the upper and lower iron yokes, and then use the magnetic medium on the rotating ring passing through this position to be magnetized in the background magnetic field, generating a higher induced magnetic field. A high gradient magnetic field is formed on the surface of the magnetic medium. The weakly magnetic minerals in the slurry are adsorbed on the magnetic medium and are carried into the upper non-magnetic field zone of the vertical ring high gradient magnetic separator as the rotating ring rotates. The magnetic medium is quickly demagnetized and washed by the flushing water into the magnetic product receiving hopper and discharged. The non-magnetic minerals flow into the tailings hopper along the gap of the lower iron yoke and are discharged, thereby achieving the separation of weakly magnetic minerals and non-magnetic minerals.

[0003] Currently, existing excitation coils have the following technical defects: (1) The excitation coils on magnetic separators mostly adopt a single electromagnetic wire structure. When operating under high voltage (such as 450V DC) and high current (up to 400A) conditions for a long time, problems such as coil heating, insulation aging and wire deformation are likely to occur. This not only affects the service life of the coil, but may also cause the magnetic separator to stop due to coil failure, affecting the continuity of production. (2) The existing magnetic separators rely on the voltage regulation or current limiting of external power supply equipment for the adjustment of excitation current. They do not start from the design of the coil structure itself to achieve stable current control. When the equipment load fluctuates or the grid voltage changes, the coil current is prone to fluctuation, which leads to unstable magnetic field strength and affects the sorting accuracy. Summary of the Invention

[0004] The purpose of this invention is to provide a high-gradient vertical ring magnetic separator excitation coil to solve the problems of short service life and poor magnetic field stability of existing excitation coils mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention includes a coil body and a junction box. The coil body is composed of several independent disc coils stacked sequentially along the axial direction. Each disc coil has two sets of terminals. The junction box is provided with terminals that correspond one-to-one with each terminal. Each terminal is electrically connected to the terminals one-to-one through external wiring. The terminals are electrically connected to each other through switchable connecting components, so as to realize adjustable control of the number of disc coils connected to the circuit and the series-parallel combination mode. The disc coil is wound with aluminum flat wire. The outer side of the aluminum flat wire is provided with an insulating coating, a glass fiber covering layer and an auxiliary stabilizing layer from the inside to the outside.

[0006] Preferably, by weight percentage, the proportions of the components of the auxiliary stabilizing layer are: 60%–70% impregnating resin, 15%–20% nano-silicon carbide, 10%–15% aluminum hydroxide, 2%–4% coupling agent, and 1%–3% anti-aging agent, with the total proportion of each component being 100%.

[0007] Preferably, the inner cavity of the junction box is divided into a lead wire working area, at least one wiring working area, and a spare wiring area according to functional partitions. The lead wire working area is provided with a positive terminal and a negative terminal. One end of the negative terminal is connected to the negative busbar, and one end of the positive terminal is connected to the positive busbar. The spare wiring area is provided with multiple auxiliary terminals. Each wiring working area is provided with several main terminals. The main terminals and auxiliary terminals are electrically connected to the terminals of each pancake coil one by one through external wiring. The main terminals in each wiring working area are connected by connecting components to realize circuit switching and loop switching.

[0008] Preferably, the connecting component includes a switch disposed in each wiring work area. One end of the switch is provided with two sets of input pins, which are electrically connected to the negative bus and the positive bus, respectively. The other end of the switch is provided with multiple sets of output pins, and each output pin is connected to the main terminal block in the corresponding wiring work area through a wire.

[0009] Preferably, the connecting component includes two sets of main terminals located in each wiring work area. The disc coils connected in the same wiring work area are connected in series by wires to form an independent coil unit. The two ends of the coil unit are electrically connected to the two sets of main terminals respectively. The two sets of main terminals are electrically connected to the negative bus and the positive bus respectively.

[0010] Preferably, the thickness of the auxiliary stabilizing layer is 0.3 to 0.5 mm.

[0011] Preferably, a plurality of insulating spacers are provided between adjacent disc coils.

[0012] After adopting the above technical solution, the beneficial effects of the present invention are: 1. This invention uses multiple independent disc coils stacked axially to form the coil body. Combined with the partitioned wiring structure and connecting components in the junction box, the number of circuits connected to the disc coil and the series-parallel combination method can be flexibly adjusted. It does not rely on external power supply equipment for voltage regulation and current limiting. The working current and magnetic field strength can be precisely controlled from the coil body structure level. 2. The aluminum flat wire is layered with an insulating coating, a glass fiber covering layer and a composite auxiliary stabilizing layer, which greatly improves the insulation performance, high temperature resistance and structural stability of the coil. It can effectively avoid problems such as insulation aging, wire deformation, leakage and short circuit that occur under long-term high voltage and high current conditions, significantly extend the service life of the excitation coil and reduce the probability of equipment failure. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0014] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a wiring diagram of Embodiment 1 of the connecting component; Figure 3 This is a wiring diagram of Embodiment 2 for the connecting component; Figure 4 This is a schematic diagram of the adjustment of the switch.

[0015] In the diagram: 1-Coil body, 2-Disc coil, 3-Insulating strip, 4-Terminal, 5-Junction box, 6-External wiring, 7-Leading work area, 8-Wiring work area, 9-Spare wiring area, 10-Secondary terminal, 11-Main terminal, 12-Negative busbar, 13-Positive busbar, 14-Positive terminal, 15-Negative terminal, 16-Main terminal, 17-Changeover switch, 18-Output pin, 19-Input pin. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0017] Currently, in conventional vertical ring magnetic separators on the market, the terminals between the excitation coils are usually encapsulated inside the coil. Once one set of coils is damaged, the machine must be disassembled for repair, and the fault point must be checked one by one. This involves a large amount of maintenance work, long downtime, and seriously affects production efficiency. This invention adopts an external wiring design, which centrally arranges the terminals of each set of coils 2 in the cavity of the junction box 5 outside the equipment. Without disassembling the entire coil structure, the faulty circuit can be quickly located in the external junction box 5.

[0018] like Figure 1As shown, in this embodiment, the coil body 1 is composed of nineteen independent disc coils 2 stacked sequentially along the axial direction. Eighteen disc coils 2 serve as working coils, while the remaining disc coil 2 is a spare coil, used to switch and replace the faulty coil 2, ensuring the normal operation of the magnetic separator. The eighteen disc coils 2 are connected in a six-series, three-parallel configuration: first, the eighteen disc coils 2 are divided into three groups, each containing six disc coils 2; the six disc coils 2 within each group are connected in series to form a coil unit; then, these three coil units are connected in parallel to the circuit. This connection method ensures a moderate total resistance of the coil body 1, allowing for a larger excitation current and a stable background magnetic field under conventional power supply voltage.

[0019] Between each pair of adjacent disc coils 2, several insulating strips 3 are arranged along the coil winding direction. The insulating strips 3 provide support and isolation for adjacent disc coils 2, maintaining a stable interlayer spacing, effectively preventing electrical short circuits caused by coil contact, and significantly improving the overall insulation performance of the coils. At the same time, the uniform gaps formed by the insulating strips 3 can serve as heat dissipation channels, effectively improving the heat dissipation conditions after coil stacking, accelerating the dissipation of working heat, avoiding problems such as coil heat accumulation aging and high-temperature deformation, and ensuring the long-term stable operation of the excitation coil.

[0020] The disc coil 2 is wound from aluminum flat wire with a cross-sectional area of ​​4.5mm × 10mm. The raw material for this aluminum flat wire is industrial pure aluminum of grade 1070 with a conductivity ≥61% IACS. To improve the insulation reliability, temperature resistance, and operational stability of the coil body 1, an insulating coating, a glass fiber covering layer, and an auxiliary stabilizing layer are arranged sequentially from the inside out on the outer side of the aluminum flat wire. The insulating coating is formed by applying and curing epoxy resin insulating varnish, and the glass fiber covering layer adopts a double-layer glass fiber cross-wrapping structure with different diameters to improve insulation performance and mechanical strength.

[0021] The components in the auxiliary stabilizing layer, by weight percentage, are as follows: impregnation resin (Erenatas, EPOXYLITE 006-0841, H-grade solvent-free epoxy impregnation resin) 60%–70%, nano-silicon carbide (particle size 20–80 nm) 15%–20%, aluminum hydroxide (particle size 1–10 μm) 10%–15%, coupling agent (Nanjing Silicon Innovation, Siwin-G20, γ-glycidyl etheroxypropyltrimethoxysilane) 2%–4%, and anti-aging agent (BASF, Irganox 3114, high-temperature hindered phenolic antioxidant) 1%–3%, with the total percentage of each component being 100%.

[0022] The preparation process of the auxiliary stabilizing layer is as follows: after the components are mixed evenly, they are coated on the outside of the glass fiber coating layer with a coating thickness of 0.3 to 0.5 mm. Then, a high-temperature curing treatment is carried out, with the curing temperature controlled at 180 to 200°C and the curing time at 2 to 3 hours, to ensure that the auxiliary stabilizing layer and the glass fiber coating layer are tightly bonded and free from defects such as bubbles and cracks.

[0023] The epoxy impregnation resin exhibits excellent adhesion to the glass fiber coating layer, bonding the glass fiber and aluminum flat wire into a unified structure, thus enhancing the overall structural integrity of the disc coil 2. Nano-silicon carbide possesses superior thermal conductivity and wear resistance, accelerating heat dissipation during operation, reducing temperature rise, and simultaneously increasing mechanical strength. Aluminum hydroxide provides flame retardancy, preventing combustion due to overheating and improving safety. The coupling agent strengthens the bond between the auxiliary stabilizing layer and the glass fiber coating layer, preventing delamination. The anti-aging agent slows down the aging of the auxiliary stabilizing layer, adapting to long-term high-voltage, high-current operation and extending the service life of the disc coil 2.

[0024] like Figure 1 and Figure 2 As shown, the interior of junction box 5 is functionally divided into one lead-in working area 7, three wiring working areas 8, and one spare wiring area 9. The lead-in working area 7 contains positive terminals 14 and negative terminals 15, which are installed using insert injection molding. Each wiring working area 8 contains six pairs of main terminals 16, and the spare wiring area 9 contains one pair of auxiliary terminals 10. All of these terminals penetrate the junction box 5, with one end remaining inside the box and the other end protruding from the bottom of the box.

[0025] The negative terminal 15, located inside the box, is electrically connected to the negative busbar 12, while the inner end of the positive terminal 14 is electrically connected to the positive busbar 13, forming a basic power supply circuit. Each disc coil 2 has a lead-out terminal 4 at both ends. Each main terminal 16 and auxiliary terminal 10 is electrically connected to the corresponding disc coil 2's lead-out terminal 4 via an external lead-out terminal 6. Nameplates identifying the corresponding numbers of the disc coils 2 are fixedly installed on both the inner and outer bottom surfaces of the junction box 5. These nameplates are arranged between pairs of terminals for easy identification of the disc coil 2 groups.

[0026] Each main terminal 16 and auxiliary terminal 10 is connected to the power supply circuit composed of the negative busbar 12 and the positive busbar 13 through a connecting component, realizing the circuit switching and circuit switching of the pancake coil 2. The connecting component is divided into manual and automatic types, which are used to realize series and parallel combination control under different modes.

[0027] like Figure 2As shown, the manual connection component includes a pair of main terminals 11 arranged in each wiring work area 8. The main terminals 11 are fixedly installed by a nut seat pre-embedded in the bottom of the junction box 5. Within the same wiring work area 8, each pair of main terminals 16 is electrically connected in sequence by wires, so that each connected disc coil 2 is connected in series to form an independent coil unit. The main terminals 16 at both ends of the coil unit are electrically connected to the two main terminals 11 in the corresponding wiring work area 8 one by one by wires. The two main terminals 11 are then connected to the negative busbar 12 and the positive busbar 13 by wires, respectively, thus forming a complete power supply circuit.

[0028] When in use, the staff can open the junction box 5 and adjust the connection point by removing and installing the wires. They can select to connect or disconnect the disc coil 2 as needed, and change the number of coils in series to adjust the excitation magnetic field strength to meet the sorting requirements of different materials.

[0029] like Figure 3 As shown, the automatic connection component includes a switch 17 installed in each wiring work area 8. The switch 17 is fixed to the inner bottom of the junction box 5 by bolts, realizing automatic control of the number of circuits connected to the disc coil 2 and the series-parallel combination method. The top of the switch 17 is provided with a pair of input pins 19, which are electrically connected to the negative bus 12 and the positive bus 13 respectively, thereby connecting to the power supply circuit. The bottom of the switch 17 is provided with six pairs of output pins 18, and each output pin 18 is connected to the corresponding main terminal 16 in the wiring work area 8 through wires.

[0030] The changeover switch 17 adopts a mature and existing electronic control switch structure. Its specific structure and working principle are well-known technologies in this field and will not be described in detail in this article.

[0031] Reference Figure 4 The diagram showing the adjustment of switch 17 illustrates the following: When switch S0 connected to the input pin 19 circuit is open, switch 17 loses power supply, and all pancake coils 2 in the current wiring working area 8 are not connected to the circuit, resulting in no excitation current in this area. When switch S0 is closed, switch 17 receives power from the positive and negative busbars, and its internal S1 to S6 switches control the on / off state of each group of pancake coils 2. When switch S1 is closed, the first pancake coil 2 can be connected to the power supply circuit alone to generate an excitation magnetic field. When switches S1 and S2 are closed, the two pancake coils 2 are connected to the power supply circuit in series. Similarly, when switches S1 to S6 are all closed, all six pancake coils 2 in the wiring working area 8 are connected to the power supply circuit in series, forming a complete coil series chain. At this time, the total ampere-turns generated are the sum of the ampere-turns of each coil, and the excitation magnetic field reaches the maximum value of this working area in the current connection mode.

[0032] The disc coil 2 connected to the auxiliary terminal 10 is a spare part and does not participate in the operation. When a disc coil 2 fails, it can be manually switched to the spare disc coil 2 by external wiring. Before the coil parts arrive, it can be quickly repaired and the machine can be started normally, avoiding long-term machine downtime and production stoppage, and greatly reducing the production losses caused by on-site failures.

[0033] Example 1 This embodiment provides an excitation coil structure adapted to a 2000 model high gradient vertical ring magnetic separator. The components of the auxiliary stabilizing layer, by weight percentage, include: 70% impregnating resin, 15% nano silicon carbide, 10% aluminum hydroxide, 2% coupling agent, and 3% anti-aging agent. After the components are mixed evenly, they are coated on the outside of the glass fiber coating layer with a thickness of 0.3 mm, and then cured at 180°C for 2.5 hours to form a tightly bonded auxiliary stabilizing layer.

[0034] The system uses a six-series, three-parallel connection to ensure a stable current of 200A±2A under 450V DC voltage.

[0035] Example 2 This embodiment provides an excitation coil structure adapted to a 4000 model high gradient vertical ring magnetic separator. The components of the auxiliary stabilizing layer, by weight percentage, include: 65% impregnating resin, 17% nano silicon carbide, 13% aluminum hydroxide, 3% coupling agent, and 2% anti-aging agent. After the components are mixed evenly, they are coated on the outside of the glass fiber coating layer with a thickness of 0.4 mm, and then cured at 180°C for 2.5 hours to form a tightly bonded auxiliary stabilizing layer.

[0036] The six-series, five-parallel connection method is adopted. By increasing the number of parallel groups, the total impedance of the coil is reduced, ensuring that the current is stable at 400A±2A under 450V DC voltage.

[0037] Example 3 This embodiment provides an excitation coil structure adapted to a 4500 model high gradient vertical ring magnetic separator. The components of the auxiliary stabilizing layer, by weight percentage, include: 60% impregnating resin, 20% nano silicon carbide, 15% aluminum hydroxide, 4% coupling agent, and 1% anti-aging agent. After the components are mixed evenly, they are coated on the outside of the glass fiber coating layer with a thickness of 0.5 mm, and then cured at 180°C for 3 hours to form a tightly bonded auxiliary stabilizing layer.

[0038] A six-series, six-parallel connection is adopted. By increasing the number of parallel groups, the total impedance of the coil is reduced, ensuring that the current is stable at 450A±2A under 450V DC voltage.

[0039] In each embodiment, the auxiliary stabilizing layer and the glass fiber covering layer are tightly bonded, without defects such as delamination or bubbles, and the insulation life of the coil is not less than 20,000 hours under continuous operation at 180°C.

Claims

1. A high-gradient magnetic separator ring magnet, characterized in that: The device includes a coil body (1) and a junction box (5). The coil body (1) is composed of several independent disc coils (2) stacked sequentially along the axial direction. Each disc coil (2) has two sets of terminals (4) leading out. The junction box (5) is provided with terminals that correspond one-to-one with each terminal (4). Each terminal (4) is electrically connected to the terminal through an external wire (6). The terminals are electrically connected to each other through connecting components, so as to realize the adjustable control of the number of disc coils (2) connected to the circuit and the series and parallel combination method. The disc coil (2) is made of aluminum flat wire. The outer side of the aluminum flat wire is provided with an insulating coating, a glass fiber covering layer and an auxiliary stabilizing layer from the inside to the outside. The inner cavity of the junction box (5) is divided into a lead wire section according to the functional area. The circuit includes a working area (7), at least one wiring working area (8), and a spare wiring area (9). The wiring working area (7) is provided with a positive terminal (14) and a negative terminal (15). One end of the negative terminal (15) is connected to the negative bus (12), and one end of the positive terminal (14) is connected to the positive bus (13). The spare wiring area (9) is provided with multiple auxiliary terminals (10). Each wiring working area (8) is provided with several main terminals (16). The main terminals (16) and auxiliary terminals (10) are electrically connected to the terminals (4) of each pancake coil (2) through external wiring (6). The main terminals (16) in each wiring working area (8) are connected to each other to achieve circuit switching and loop switching through connecting components.

2. The high gradient vertical ring magnetic separator field coil of claim 1, wherein, The auxiliary stabilizing layer comprises, by weight percentage: 60%–70% impregnating resin, 15%–20% nano-silicon carbide, 10%–15% aluminum hydroxide, 2%–4% coupling agent, and 1%–3% anti-aging agent, with the total percentage of each component being 100%.

3. The excitation coil of the high-gradient vertical ring magnetic separator according to claim 1, characterized in that: The connecting component includes a switch (17) disposed in each wiring work area (8). One end of the switch (17) is provided with two sets of input pins (19), which are electrically connected to the negative bus (12) and the positive bus (13) respectively. The other end of the switch (17) is provided with multiple sets of output pins (18), and each output pin (18) is connected to the main terminal (16) in the corresponding wiring work area (8) through a wire.

4. The excitation coil of the high-gradient vertical ring magnetic separator according to claim 1, characterized in that: The connecting component includes two sets of main terminals (11) located in each wiring work area (8). The pancake coils (2) connected in the same wiring work area (8) are connected in series by wires to form independent coil units. The two ends of the coil units are electrically connected to the two sets of main terminals (11) one by one. The two sets of main terminals (11) are electrically connected to the negative bus (12) and the positive bus (13) respectively.

5. The excitation coil of the high-gradient vertical ring magnetic separator according to claim 1, characterized in that: The thickness of the auxiliary stabilizing layer is 0.3–0.5 mm.

6. The excitation coil of the high-gradient vertical ring magnetic separator according to claim 1, characterized in that: Several insulating spacers (3) are provided between adjacent disc coils (2).

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