Induction heating device and application thereof

Abstract

The present invention provides an induction heating device and its application, belonging to the field of mechanical sheet metal technology. The induction heating device includes a bracket and an induction heating coil; the bracket can support the induction heating coil; the induction heating coil includes two layers of coils, namely an upper coil and a lower coil; the lower coil is located below the upper coil; and the upper coil is connected to the lower coil. The present invention can be used to heat the strip, so that the machining thickness of ordinary spiral ducts can be increased from less than 1.2mm to 5mm, and the thick-walled spiral ducts after forming have good bite quality, good sealing, and greatly improved ring stiffness and compressive strength.

Description

Technical Field

[0001] The present invention belongs to the technical field of mechanical sheet metal, and in particular relates to an induction heating device and application thereof. Background Art

[0002] At present, the spiral ducts produced by the bite molding method generally have a wall thickness limited to less than 1.2mm and a diameter of less than 1500mm. They were first used in the field of ventilation and cooling, and then gradually expanded to the fields of purification system return air ducts, central air conditioning ventilation ducts, industrial supply and exhaust ventilation ducts, mine gas extraction pipes, and mine rubberized cloth air ducts.

[0003] Due to the advantages of spiral duct forming technology, good sealing, high ring stiffness and so on, the spiral duct has begun to be promoted and tried in special occasions such as aerospace ventilation, liquid delivery systems, and nuclear submarine ventilation systems.

[0004] However, due to the limitation of the spiral duct rolling mill capacity, the thickness of the currently formed strip is generally between 0.4mm and 1.2mm, and its material is mainly galvanized sheet, pure aluminum sheet, stainless steel, etc. with good plasticity, which greatly limits the widespread application of spiral ducts.

[0005] When the thickness of the formed strip material expands to 2-5mm, it is difficult for the spiral duct machines currently on the market to form a bite mouth. In addition, there are certain requirements for the material of the formed plate. The plate must have good plasticity, that is, the elongation is above 20%; low strength, that is, the yield strength is below 250Mpa; and it is not easy to spirally bite the plate and strip with poor room temperature plasticity (elongation is 6%-20%) and high strength (yield strength is above 250Mpa). Summary of the Invention

[0006] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and provide an induction heating device and its application, which can heat the strip and is used to heat the strip so that thicker strips can also be processed by the spiral duct machine, and improve the bite quality, sealing, ring stiffness and compressive strength of the thick-walled spiral duct after forming.

[0007] The present invention is achieved through the following technical solutions:

[0008] An induction heating device, comprising a bracket and an induction heating coil;

[0009] The bracket is capable of supporting the induction heating coil;

[0010] The induction heating coil includes two layers of coils, an upper coil and a lower coil;

[0011] The lower coil is located below the upper coil;

[0012] The upper coil is communicated with the lower coil.

[0013] A structure of the induction heating coil is:

[0014] The induction heating coil adopts a C-type induction coil;

[0015] The upper coil in the C-shaped induction coil includes a plurality of U-shaped coils connected in sequence;

[0016] The lower coil in the C-shaped induction coil also includes a plurality of U-shaped coils connected in sequence;

[0017] The upper coil and the lower coil are arranged in parallel.

[0018] Preferably, the inlet of the upper coil is a water inlet, and the outlet of the upper coil is connected to the inlet of the lower coil through a straight tube coil;

[0019] The outlet of the lower coil is a water outlet.

[0020] Preferably, the straight tube coil is perpendicular to the plane where the upper coil is located and the plane where the lower coil is located.

[0021] Another structure of the induction heating coil is:

[0022] The induction coil is a linear induction coil;

[0023] The upper coil and the lower coil in the linear induction coil are both straight tube coils;

[0024] Two straight tube coils are arranged in parallel above and below.

[0025] Preferably, the inlet of the upper coil is a water inlet, the outlet of the upper coil is connected to the inlet of the lower coil through a U-shaped coil, and the outlet of the lower coil is a water outlet.

[0026] Preferably, the plane where the U-shaped coil is located is perpendicular to the plane where the upper coil and the lower coil are located.

[0027] The application method of the above-mentioned induction heating device is as follows:

[0028] (1) Select the induction heating device according to the heating area of the strip;

[0029] (2) Two sets of the above-mentioned induction heating devices are symmetrically installed on both sides of the strip;

[0030] (3) Turn on the induction heating device to heat both sides of the strip.

[0031] The operation of step (1) includes:

[0032] If the heating area of the strip is the edges on both sides of the strip, choose an induction heating device equipped with a C-shaped induction coil;

[0033] If the heating area of the strip is the bite bending area on both sides of the strip, an induction heating device equipped with a linear induction coil is selected.

[0034] The operation of step (2) includes:

[0035] The support of the first set of induction heating devices is fixedly installed on one side of the outside of the strip material, so that the side of the strip material is located between the upper coil and the lower coil of the set of induction heating devices;

[0036] The bracket of the second set of induction heating devices is fixedly installed on the other side of the strip, so that the side of the strip is located between the upper coil and the lower coil of the set of induction heating devices.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The present invention can be used to heat the strip, so that the machining thickness of the ordinary spiral duct is increased from less than 1.2mm to 5mm, and the thick-walled spiral duct after forming has good bite quality, good sealing, and greatly improved ring stiffness and compressive strength.

[0039] 2. By adding the induction heating device of the present invention to the spiral duct forming device, the material selection range of the spiral duct is greatly expanded. The spiral duct forming material is no longer limited to galvanized sheet, pure aluminum sheet, stainless steel, etc. with good plasticity and low strength. Some materials with poor room temperature plasticity, high strength, but good high-temperature plasticity can be selected, such as 7075 high-strength aluminum alloy, 2A02 aluminum alloy, TC4, TB2 titanium alloy, Mg-Nd-Y-Zr and other rare earth magnesium alloys, TiAl-based alloys, etc., thereby expanding the use of spiral ducts to the high-temperature resistant field of aerospace, or special military occasions such as ventilation systems for ships and nuclear submarines. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a structural schematic diagram of the induction heating device of the present invention.

[0041] Figure 2 Schematic diagram of a C-shaped induction heating coil in the induction heating device of the present invention.

[0042] Figure 3 Schematic diagram of a linear induction heating coil in the induction heating device of the present invention.

[0043] Figure 4 It is a structural schematic diagram of the induction heating device of the present invention.

[0044] Figure 5 Schematic diagram of a strip formed by using a bite forming unit in the spiral duct forming device of the present invention in an embodiment.

[0045] Figure 6 Schematic diagram of the cross-sectional structure of a spiral duct manufactured using the spiral duct forming device of the present invention in an embodiment.

[0046] In the figure: 1. Unwinding device, 2. Induction heating device, 3. Infrared temperature sensor, 4. Temperature controller, 5. Induction heating control system, 6. Bite forming unit, 7. First bite roller group, 8. Second bite roller group, 9. Third bite roller group, 10. Bite pressing unit, 11. Bite pressing forming unit, 12. Upper pressing wheel, 13. Lower pressing wheel, 14. Coil mold, 15. Thick-walled spiral duct, 16. Automatic duct cutting device, 17. First support frame, 18. Second support frame, 19. Infrared sensing device, 20. Lower bite, 21. Upper bite, 22. Water inlet, 23. Water outlet. DETAILED DESCRIPTION

[0047] The present invention is further described in detail below with reference to the accompanying drawings:

[0048] The present invention can heat galvanized sheets, pure aluminum sheets, stainless steel strips with a thickness of 1.2mm-5mm or metal strips with a thickness of 0.8-5mm that have poor room temperature plasticity, high strength, high temperature resistance, and are difficult to deform, and use the existing spiral duct forming device to spirally bite the heated strips.

[0049] like Figures 1 to 3 As shown, the induction heating device 2 of the present invention includes a bracket and an induction heating coil. The bracket can adopt a variety of structures to support the induction heating coil, and the bracket can be installed on both sides of the strip. The specific structure can be designed as needed, such as a clamping bracket that can be clamped on the production line, a threaded bracket that can be fixed on the production line by bolts, etc. The frequency of the induction heating coil is medium frequency. The induction heating coil adopts the existing electromagnetic induction heating coil, which is hollow. It is energized and cooling water is passed into its inner cavity. Its structure and other structures connected to it (such as cooling water pump, control system, AC power supply, etc., the AC power supply energizes the induction coil, and the cooling pump is used to circulate cooling water in the induction coil) and working principle are not described in detail here.

[0050] The induction heating coil can be a C-shaped induction coil or a linear induction coil, and the cross-sectional shape of the coil can be a rectangular, square, regular hexagonal, circular or other shapes.

[0051] Figure 1 It is a structural diagram. Figure 1Two U-shaped plates are used to represent the induction heating device 2. Figure 2 、 Figure 3 It is a specific form of induction heating device.

[0052] The C-type induction coil is as follows Figure 2 As shown, it includes two layers of coils, namely an upper coil and a lower coil. The upper coil is located above, and the lower coil is located below the upper coil. The upper coil includes multiple U-shaped coils connected in sequence, and the lower coil also includes multiple U-shaped coils connected in sequence. The upper coil and the lower coil are arranged in parallel. The inlet of the upper coil is the water inlet 22, and the outlet of the upper coil is connected to the inlet of the lower coil through a straight tube coil. The straight tube coil is perpendicular to the plane where the upper coil and the plane where the lower coil are located. The outlet of the lower coil is the water outlet 23. Cooling water enters from the water inlet 22, passes through the upper coil, the straight tube, and the lower coil in sequence, and then flows out from the water outlet 23.

[0053] The linear induction coil is as follows Figure 3 As shown, it includes two layers of coils, namely the upper coil and the lower coil. The upper coil is located above, and the lower coil is located below the upper coil. Both the upper coil and the lower coil are straight tube coils. The two straight tube coils are arranged in parallel, upper and lower. The inlet of the upper coil is the water inlet, and the outlet of the upper coil is connected to the inlet of the lower coil through a U-shaped coil. The outlet of the lower coil is the water outlet. Cooling water enters from the water inlet, passes through the upper coil, the U-shaped coil, and the lower coil in sequence, and flows out from the water outlet. The plane where the U-shaped coil is located is perpendicular to the plane where the upper coil and the lower coil are located.

[0054] The heating area is related to the width of the induction heating coil used. Specifically, C-type induction coils are used for localized heating, while linear induction coils are used for line heating. For spiral ducts with a diameter of 100-150mm, the strip width used is 90-120mm. If heating is required on both sides of the strip where the seam is to be formed, the heating area is within 20mm of the edges on both sides. In this case, a C-type induction coil is used for heating. If heating is only required for the bend area (approximately 10mm) of the strip where the seam is to be formed, a linear induction coil is used for heating.

[0055] The application method of the induction heating device of the present invention is as follows:

[0056] Select an induction heating device based on the heating area of the strip. Specifically, if you want to heat both sides of the strip, choose an induction heating device equipped with a C-shaped induction coil; if you want to heat only the bend area of the strip, choose an induction heating device equipped with a linear induction coil.

[0057] Two sets of the above-mentioned induction heating devices are symmetrically installed on both sides of the strip: the bracket of the first set of induction heating devices is fixedly installed on one side of the outside of the strip, and the strip is located between the upper coil and the lower coil of the induction heating device;

[0058] The support of the second induction heating device is fixedly installed on the other side of the strip, and the strip is positioned between the upper coil and the lower coil of the induction heating device;

[0059] Turn on the induction heating device for heating.

[0060] The induction heating device of the present invention can be used in a variety of systems that require heating. In this embodiment, the induction heating device is installed in a spiral duct forming device. Specifically, Figure 4 As shown, the existing spiral duct forming device includes, arranged in sequence from front to back: an unwinding device 1, a bite forming unit 6, a bite pressing unit 10, an automatic duct cutting device 16 and a support frame. In this embodiment, the induction heating device of the present invention is installed between the unwinding device 1 and the bite forming unit 6. Figure 4 In the figure, the infrared temperature sensor 3, the induction heating device 2, and the temperature controller 4 are collectively referred to as the induction heating control system 5. The front and back are described here based on the order in which the strip passes. For example, the unwinding device 1 is set in front of the induction heating device 2, and the bite forming unit 6 is set in the back of the induction heating device 2, and so on. Figure 4 Except for the induction heating device, the other devices in the spiral duct forming device shown are existing devices in the existing spiral duct forming device.

[0061] A set of induction heating devices 2 are symmetrically positioned on either side of the strip. The induction heating device 2 on one side heats the upper bite portion, which requires upward bending, while the induction heating device 2 on the other side heats the lower bite portion, which requires downward bending. One side of the strip is positioned between the upper and lower coils of one set of induction heating devices 2, while the other side of the strip is positioned between the upper and lower coils of the other set of induction heating devices 2.

[0062] In order to measure the temperature and control the heating time, an infrared temperature sensor 3 is provided directly above the induction heating device 2 to detect the real-time temperature of the induction heating strip. Furthermore, a temperature controller 4 is also provided. Specifically, the infrared temperature sensor 3 and the temperature controller 4 are both existing devices, and their structures and working principles are not described in detail here. The infrared temperature sensor 3 is respectively connected to the induction heating device 2 and the temperature controller 4 on both sides of the strip. The two sensing ends of the infrared temperature sensor 3 are respectively located on both sides of the strip to sense the temperature on both sides of the strip. At the same time, the temperature controller is connected to the control system of the induction heating device. When the temperature controller signal is sent, it is transmitted to the control system of the induction heating device. The induction heating control system cuts off the power supply, thereby stopping the heating of the induction coil. Figure 1 and Figure 3 The two straight lines extending from the mid-infrared temperature sensor 3 and pointing to the strip represent the two sensing ends of the infrared temperature sensor, which respectively sense the temperatures on both sides of the strip.

[0063] Depending on the material of the spiral duct selected, the material is heated to a temperature range that is easy to form. Taking 7075 aluminum alloy strip as an example, the thickness of the formed strip is 2.5mm, the induction heating temperature is between 370-420℃, and the induction heating time is about 10s-15s. When the temperature of the heated area of the strip reaches the predetermined value, the temperature is fed back to the temperature controller in real time through the infrared temperature sensor.

[0064] After the unwinding device 1 unwinds the strip, the strip is heated by the induction heating device. During the induction heating process, the strip passes through the induction heating device at a rate of 1-30m / min, and then undergoes a series of subsequent forming processes such as bite folding and bite pressing. Once an abnormal situation occurs, such as when the temperature exceeds a predetermined value, the infrared temperature sensor will transmit the temperature data to the temperature controller in real time, and the temperature controller will automatically cut off the power supply of the induction heating device to stop heating.

[0065] After the strip passes through the induction heating control system 5, it enters the bite forming unit 6, which includes three groups of bite roller groups (three groups of bite roller groups are used in this embodiment, and the number of bite roller groups can be set according to needs), namely the first bite roller group 7, the second bite roller group 8, and the third bite roller group 9. Each group of bite roller groups includes two forming rollers arranged upper and lower. After the strip passes through the bite forming unit 6, a lower bite 20 is formed on one side of the strip, and an upper bite 22 is formed on the other side; Figure 5 shown.

[0066] After the strip comes out of the bite forming unit 6, it enters the bite pressing unit 10, which includes: a bite pressing forming machine 11 and a strip coil mold 14. The bite pressing forming unit 11 includes an upper pressing wheel 12 and a lower pressing wheel 13 arranged above and below. The upper and lower bite wheels press and compact the bite to complete the bite edge pressing work;

[0067] The support frame includes a first support frame 17 and a second support frame 18. An automatic air duct cutting device 16, a first support frame 17 and a second support frame 18 are sequentially arranged behind the bite pressing unit 10. The formed spiral air duct advances in a spiral under the support of the first support frame 16, and an infrared sensing device 19 is installed on the side wall of the second support frame 18; the infrared sensing device 19 is connected to the automatic air duct cutting device 16 through a wire. When sensing that the spiral air duct passes through, the infrared sensing device 19 transmits data to the automatic air duct cutting device; the automatic air duct cutting device is installed with cutting teeth to cut the spiral air duct into pipes of a certain length, such as Figure 6 shown.

[0068] By using a spiral duct forming device equipped with the induction heating device of the present invention, it is possible to produce spiral ducts made of conventional materials with a thick wall of up to 5 mm or spiral ducts made of difficult-to-deform metals (7075 high-strength aluminum alloy, TC4 titanium alloy, etc.) with a thickness of 0.8-5 mm. These ducts can be used in high-temperature resistant environments, thereby expanding the application field of spiral ducts, especially in special occasions such as aerospace, nuclear submarines, etc.

[0069] The embodiments of the present invention are as follows:

[0070] Example 1:

[0071] The strip with a thickness of 1.2-5mm is unwound from the unwinding device 1, and then the two sides of the strip are locally heated by the induction heating control system 5. The induction heating device 2 heats the two sides of the strip, and the infrared temperature sensor 3 monitors the temperature of the formed strip. Once there is an abnormality, the signal is transmitted to the temperature controller 4 to stop heating; under normal circumstances, after the edge of the strip is heated, it enters the bite forming unit 6 at a certain speed (1-30m / min) to perform flanging and bite forming on the edge. After the two sides of the strip pass through the first bite roller group 7, the second bite roller group 8, and the third bite roller group 9 in turn, the strip is One side bends downward to form a lower bite, and the other side bends upward to form an upper bite. Then the plate strip enters the bite pressing unit 10. Under the operation of the bite pressing machine 11, the strip passes through the strip roll mold 14 to form a spiral bend, so that the lower bite of the plate strip enters the upper bite. Under the bite pressing action of the upper pressing wheel 12 and the lower pressing wheel 13, a sealed bite rib is formed, which spirally surrounds the outside (or inside) of the air duct. When the production of the spiral air duct reaches a certain length, the sensor 19 on the second support frame 18 will transmit the signal to the air duct automatic cutting device 16, and the air duct automatic cutting device 16 starts to work and cuts off the spiral air duct.

[0072] Example 2:

[0073] The induction heating control system 5 described in Example 1 has a controllable heating temperature, and the induction heating coil is medium frequency. Different heating temperatures can be set according to the material of the strip. Taking 7075 aluminum alloy strip as an example, the thickness of the formed strip is 2.5 mm, and its induction heating temperature is between 370-420°C, and the induction heating time is about 10s-15s; taking TC4 titanium alloy strip as an example, the thickness of the formed strip is 3 mm, and its induction heating temperature is between 800-950°C, and the induction heating time is about 15-20s; when the temperature of the heated area of the strip reaches the predetermined value, the temperature is fed back to the temperature controller in real time through the infrared temperature sensor. Once a temperature abnormality occurs, the temperature controller will quickly cut off the operation of the induction heating device.

[0074] By using the induction heating device of the present invention to perform localized induction heating on a strip, spiral interlocking forming can be achieved for conventional galvanized sheet, pure aluminum sheet, stainless steel strip, or difficult-to-deform metal strip with a thickness of 1.2mm-5mm. These difficult-to-deform metal strips include 7075 high-strength aluminum alloy, 2A02 aluminum alloy, TC4 and TB2 titanium alloys, rare earth magnesium alloys such as Mg-Nd-Y-Zr, and TiAl-based alloys. This significantly expands the application of spiral ducting to high-temperature resistant aerospace applications and specialized military applications such as ventilation systems for ships and nuclear submarines. Overall, the device boasts a simple structure, easy operation, and strong practicality, making it suitable for widespread adoption.

[0075] The above technical solution is only one embodiment of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the structure described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. An induction heating device, characterized in that: The induction heating device includes a bracket and an induction heating coil; The bracket is capable of supporting the induction heating coil; The induction heating coil includes two layers of coils, an upper coil and a lower coil; The lower coil is located below the upper coil; The upper coil is connected to the lower coil; Two sets of induction heating devices are symmetrically installed on both sides of the strip: the bracket of the first set of induction heating devices is fixedly installed on one side of the outside of the strip, so that the strip is located between the upper coil and the lower coil; the bracket of the second set of induction heating devices is fixedly installed on the other side of the outside of the strip, so that the strip is located between the upper coil and the lower coil; the induction heating device on one side heats the upper bite portion that needs to be bent upward, and the induction heating device on the other side heats the lower bite portion that needs to be bent downward; The induction heating coil adopts a C-shaped induction coil; the upper coil of the C-shaped induction coil includes a plurality of U-shaped coils connected in sequence; the lower coil of the C-shaped induction coil also includes a plurality of U-shaped coils connected in sequence; the upper coil and the lower coil are arranged in parallel; the inlet of the upper coil is a water inlet, and the outlet of the upper coil is connected to the inlet of the lower coil through a straight tube coil; the outlet of the lower coil is a water outlet; the straight tube coil is perpendicular to the plane where the upper coil is located and the plane where the lower coil is located; Alternatively, the induction coil adopts a linear induction coil; the upper coil and the lower coil in the linear induction coil are both straight tube coils; the two straight tube coils are arranged in parallel above and below; the inlet of the upper coil is the water inlet, the outlet of the upper coil is connected to the inlet of the lower coil through a U-shaped coil, and the outlet of the lower coil is the water outlet; the plane where the U-shaped coil is located is perpendicular to the plane where the upper coil and the lower coil are located.

2. A method for heating a strip, characterized in that: The method comprises: (1) Select the induction heating device according to the heating area of the strip; (2) Two sets of induction heating devices as described in claim 1 are symmetrically installed on both sides of the strip; (3) Turn on the induction heating device to heat both sides of the strip; The operation of step (1) includes: If the heating area of the strip is the edges on both sides of the strip, choose an induction heating device equipped with a C-shaped induction coil; If the heating area of the strip is the bite bending area on both sides of the strip, an induction heating device equipped with a linear induction coil is selected.

3. The method according to claim 2, wherein: The operation of step (2) includes: The support of the first set of induction heating devices is fixedly installed on one side of the outside of the strip material, so that the side of the strip material is located between the upper coil and the lower coil of the set of induction heating devices; The bracket of the second set of induction heating devices is fixedly installed on the other side of the strip, so that the side of the strip is located between the upper coil and the lower coil of the set of induction heating devices.

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