Overheat protection method for multi-turn coil and cooling device thereof

Abstract

The invention belongs to the technical field of metal heat treatment, and provides an overheat protection method for a multi-turn coil and a cooling device of the multi-turn coil, before induction heating is started, the quality and the allowance of cooling liquid are automatically judged, supplementing or replacing operation is executed according to requirements, the flow and an inlet and outlet channel of the cooling liquid can be dynamically adjusted according to coil temperature changes, and the cooling efficiency is improved. The cooling device comprises a cooling supply assembly, a sliding table assembly, an infrared thermometer, a power source and a controller, a plurality of cooling liquid channels are formed in the coil and connected with a liquid supply pipeline and a liquid return pipeline through electromagnetic valves, the infrared thermometer is arranged on the sliding table assembly, and a zigzag liquid path, a turbidity sensor and a liquid level meter are arranged in the cooling supply assembly. The controller is connected with the cooling supply assembly, the sliding table assembly and the infrared thermometer through electric signals, closed-loop control between induction heating and the cooling liquid circulation state can be achieved according to the temperature change of the coil, and the heat dissipation efficiency of the coil is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of metal heat treatment, and in particular relates to an overheat protection method for a multi-turn coil and a cooling device thereof. Background Art

[0002] The coil is an inductive element made of a material with excellent conductive properties. It includes one or more conductive coil groups and has specific electromagnetic properties. By winding the wire into a spiral or other shape, when an alternating current passes through, a magnetic field of the same frequency is generated around the coil. This magnetic field can be used to achieve electromagnetic heating, induced voltage and energy storage, etc., and is widely used in various electrical and electronic equipment. However, during the working process, due to the heat conduction of resistance heat and other components, the temperature of the coil will rise, which not only reduces the efficiency and performance of the equipment, but also may cause the degradation of the insulation material, and then cause the risk of short circuit or insulation failure, seriously affecting the safety and service life of the equipment. For this reason, the coil is usually equipped with corresponding cooling measures to prevent overheating and ensure the efficient operation of the equipment. In electromagnetic heating applications, when the workpiece is placed in the magnetic field of the coil, induced eddy currents will be generated inside it, and the eddy currents will generate Joule heat in the workpiece and cause the workpiece to heat up rapidly. In this process, the electromagnetic coupling between the coil and the workpiece determines the number and density of the magnetic field lines entering the workpiece, which is a key factor affecting the heating efficiency and accuracy. However, as the temperature of the workpiece rises, the coil will also increase in temperature due to its own resistance heating and absorption of the workpiece radiation heat. The increase in temperature has many effects on the coil: First, when the temperature of the coil increases, the resistance of the conductive material increases, resulting in a weakening of the magnetic field strength generated by the coil, thereby reducing the heating efficiency and electromagnetic coupling of the workpiece. Secondly, the increase in temperature will cause thermal expansion of the material, trigger changes in the mechanical stress of the coil, and cause deformation of the coil geometry. This deformation will change the physical distance between the coil and the workpiece, and the change in distance will significantly affect the electromagnetic coupling efficiency. Especially in high-frequency electromagnetic heating, a slight change in distance will cause fluctuations in power density, which will in turn affect the heating uniformity and accuracy. In addition, if the coil is made of ferromagnetic material, the increase in temperature will also lead to a decrease in the magnetic permeability of the coil, and even lose magnetism after the temperature exceeds the Curie point, resulting in a serious imbalance in the magnetic field distribution, which will directly affect the effect of induction heating. Therefore, using effective heat dissipation and cooling technology to control the coil temperature is not only one of the key factors to ensure the normal operation of the entire induction heating system, but also an important guarantee to ensure heating accuracy and quality and promote high-end precision manufacturing.

[0003] Patent CN101162636B discloses a coil protective layer for a medium frequency furnace, which is composed of high-temperature resistant hollow balls, powder materials and binders, and plays a heat-insulating role after being coated on the surface of the coil. However, the protective layer cannot completely block the heat transfer. When the cooling effect of the coolant decreases or the heating is carried out for a long time, the temperature of the coil will continue to rise or even overheat. Patent CN214039528U discloses a coil protection device for a medium frequency induction heating furnace, which can realize automatic replenishment of the coolant. However, after the heating starts, the coil temperature is also directly affected by the heating time, heating temperature, etc. The closed-loop control between the induction heating and the coolant circulation state is realized according to the change of the coil temperature. It can not only control the temperature change of the coil, but also match the appropriate cooling hydraulic pressure and reduce the waste of resources. An effective way, and the device is essentially unable to effectively prevent the coil from overheating. Therefore, it is necessary to design an overheating protection method and a cooling device for multi-turn coils. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides an overheating protection method for a multi-turn coil and a cooling device thereof. Through an effective heat dissipation and cooling structure, combined with a system for dynamically monitoring the status of the coolant, a coil temperature control and management mechanism is established to prevent the coil from overheating due to prolonged heating, mismatch between the coil and the workpiece, and insufficient cooling hydraulic pressure, and effectively prevent the deterioration of the coolant quality due to industrial dust and metal corrosion, ensuring that the coil continues to operate stably within a safe temperature range, thereby extending the life of the equipment and improving the reliability of the cooling device.

[0005] The present invention provides an overheat protection method for a multi-turn coil, which comprises the following steps:

[0006] S1. Determine the upper limit turbidity N of the coolant according to process requirements max , determine the length L of the heated workpiece and set the first warning temperature T max1 , Second warning temperature T max2 and the third warning temperature T max3 , determine the upper limit of the liquid level H max , real-time measurement of turbidity N;

[0007] S2. Determine N≥N max Is it true? If so, go to step S3; otherwise, go to step S4;

[0008] S3, open the first solenoid valve, when the liquid level measured by the level gauge is H w =0, close the first solenoid valve and open the second solenoid valve until H w =H max When N<N max When the first solenoid valve and the second solenoid valve are closed, step S5 is executed;

[0009] S4, turn off the turbidity sensor and judge H w <H max Is it true? If H w <H max Then open the second solenoid valve until H w =H max When the second solenoid valve is closed, step S5 is executed; if H w >H max Then directly execute step S5;

[0010] S5. Select the coolant interface Y according to the axial length L of the heated workpiece m , start the motor to move the infrared thermometer to the coolant interface Y m Department;

[0011] S6, open the coolant interface Y1 and the coolant interface Y m , the coolant is delivered to the coolant interface Y1 through the liquid pump and the coolant is m outflow;

[0012] S7, determine the real-time coolant flow rate Q ≥ coolant flow rate lower limit Q min If yes, start the power supply and execute step S8. Otherwise, check whether the cooling device works normally and then re-determine whether the real-time flow rate of the coolant Q is greater than the lower limit of the flow rate of the coolant Q. min Is it established, until it is established and execute step S8;

[0013] S8, real-time monitoring of coolant interface Y m The temperature T Ym , according to T Ym Select the coolant inlet and outlet ports and determine T Ym ≥T max3 If it is established, turn off the power supply, check whether the cooling device is working properly, and then return to step S7. Otherwise, determine whether T max2 <T Ym <T max3 Is it true? If so, execute step S81 according to the coolant interface number m. Otherwise, determine T max1 <T Ym <T max2 Is it true? If so, the solenoid valve R m Switch to liquid inlet state, coolant interface Y m Switch to the liquid inlet, and execute step S82 according to the coolant interface number m. If not, directly execute step S9;

[0014] S9, turn on the power supply, determine whether the heated workpiece meets the heat treatment requirements, if yes, execute step S10, otherwise return to execute step S7;

[0015] S10, turn off the power, remove the heated workpiece, and determine T Ym <T max1 Is it true? If so, close the liquid pump and all solenoid valves. Otherwise, keep the current solenoid valve open and closed and continue cooling until T Ym <T max1 , the induction heating ends.

[0016] Preferably, step S81 is: if m=2, increase the real-time coolant flow Q and execute step S9; if m>2, the odd-numbered solenoid valves are all switched to the liquid inlet state, and the corresponding coolant interfaces are switched to the liquid inlet, and the even-numbered solenoid valves are all switched to the liquid outlet state, and the corresponding cooling interfaces are switched to the liquid outlet, and execute step S9.

[0017] Preferably, step S82 is: if m=2, solenoid valves R3~R n All are switched to the liquid outlet state, coolant interface Y3~Y n Switch to the liquid outlet, execute step S9, if m>2, solenoid valves R2~R m-1 All are switched to the liquid outlet state, coolant interface Y2~Y m-1 Switch to the liquid outlet and execute step S9.

[0018] In the second aspect, the present invention also provides a cooling device for a multi-turn coil, which includes a slide assembly, an infrared thermometer, a controller, a liquid pump, a cooling supply assembly, a solenoid valve and a power supply. The cooling supply assembly includes a liquid tank, a meandering partition, a turbidity sensor, a liquid level meter, a flow meter, a first solenoid valve and a second solenoid valve. The meandering partition is arranged in the liquid tank to form a meandering liquid path. The first end of the meandering liquid path is provided with a coil liquid inlet and a liquid tank discharge port, and the second end of the meandering liquid path is provided with a coil liquid return port and a liquid tank liquid inlet. The liquid level meter and the turbidity sensor are arranged at the coil liquid inlet, the flow meter is connected to the coil liquid inlet channel, the first solenoid valve is connected to the liquid tank discharge port, and the second solenoid valve is connected to the liquid tank liquid inlet.

[0019] Preferably, the coil is provided with a plurality of coolant interfaces, each of which is provided with the solenoid valve, and the distance D between adjacent coolant interfaces is less than D max The coolant interface is connected to the coil liquid inlet channel and the coil liquid return channel through the solenoid valve respectively.

[0020] Preferably, the slide assembly includes a temperature measuring bracket, a motor, a screw, a distance measuring bracket and a distance measuring sensor, the infrared thermometer is arranged on the temperature measuring bracket, the distance measuring sensor is arranged on the distance measuring bracket, and the controller is connected to the motor, the distance measuring sensor, the infrared thermometer, the liquid pump, the first solenoid valve, the second solenoid valve, the turbidity sensor, the liquid level meter, the flow meter, the solenoid valve, and the power supply through electrical signals respectively.

[0021] Preferably, the first solenoid valve and the second solenoid valve in the cooling supply assembly are both two-position two-way valves, the liquid circuit is closed when the valve core is in the middle position, and the liquid circuit is opened when the valve core is in motion.

[0022] Preferably, the solenoid valve is a three-position three-way valve, and the liquid circuit is closed when the valve core is in the middle position.

[0023] Preferably, the distance D between adjacent coolant interfaces is smaller than the maximum distance D max , and the maximum spacing D max The determination method is: establish the influence equation of the length L of the heated workpiece on the temperature T2 at the coil outlet, set the maximum value of the temperature T2 at the coil outlet to obtain D max , the influence equation of T2 and L is:

[0024]

[0025] Where T1 is the maximum heating temperature of the heated workpiece, T0 is the temperature at the coil entrance, σ is the Stefan-Boltzmann constant, ε is the surface emissivity, and A is s is the coil surface area, ρ is the density of the coolant, c p is the specific heat capacity of the coolant, Q min This is the lower limit of coolant flow.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The overheat protection method for a multi-turn coil of the present invention effectively prevents the accumulation of impurities caused by long-term use of the coolant by monitoring the coolant, thereby avoiding reduced cooling efficiency. The built-in liquid level gauge accurately monitors the liquid level to prevent overheating or excessive overflow of the coil caused by insufficient coolant, thereby ensuring safe operation of the equipment. A circular partition is arranged in the liquid tank, and the liquid inlet and liquid return port of the coil are placed at both ends of the partition, so that the coolant flowing back from the coil can fully dissipate heat in the partition and then re-circulate into the coil, thereby effectively improving the cooling efficiency of the coolant.

[0028] 2. The present invention is used for a cooling device for a multi-turn coil. A plurality of coolant channels are arranged on the coil and equipped with real-time temperature monitoring. When the channel temperature reaches a preset alarm threshold, the corresponding solenoid valve will automatically switch, and the flow and opening and closing states of different coolant channels will be adjusted according to the degree of temperature increase. The coolant flow and circulation mode can be automatically adjusted according to the temperature change of the coil, effectively enhancing heat dissipation.

[0029] 3. The present invention is used for a cooling device for multi-turn coils, which realizes fully integrated control of signals such as liquid level, liquid quality, temperature, etc. with solenoid valves, motors, power supplies and liquid pumps through a controller, effectively reducing manual operating errors and labor costs, and improving the automation level and reliability of the coil cooling device. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flow chart of the overheat protection method for a multi-turn coil of the present invention;

[0031] Figure 2 It is an overall schematic diagram of a cooling device for a multi-turn coil of the present invention;

[0032] Figure 3 A top view of a cooling device for a multi-turn coil according to the present invention;

[0033] Figure 4 It is a side view of a cooling device for a multi-turn coil according to the present invention.

[0034] Main reference numerals:

[0035] 1-slide assembly, 11-temperature measuring bracket, 12-motor, 13-screw, 14-distance measuring bracket, 15-distance measuring sensor, 2-infrared thermometer, 3-controller, 4-liquid pump, 5-cooling supply assembly, 51-liquid tank, 52-liquid tank inlet, 53-first solenoid valve, 54-liquid tank discharge port, 55-coil liquid inlet, 56-second solenoid valve, 57-reciprocating partition, 58-turbidity sensor, 59-liquid level meter, 510-coil return liquid port, 511-coil liquid inlet channel, 512-coil return liquid channel, 513-flow meter, 6-solenoid valve, 7-coil, 71-cooling liquid interface, 9-power supply. DETAILED DESCRIPTION

[0036] In order to fully describe the technical content, structural features, objectives and effects of the present invention, the following will be described in detail with reference to the accompanying drawings.

[0037] like Figure 1 As shown, the overheat protection method for a multi-turn coil provided by the present invention comprises the following steps:

[0038] S1. Determine the upper limit turbidity N of the coolant according to process requirements max, determine the length L of the heated workpiece and set the first warning temperature T max1 , Second warning temperature T max2 and the third warning temperature T max3 , determine the upper limit of the liquid level H max , real-time measurement of turbidity N.

[0039] S2. Determine N≥N max Is it true? If so, go to step S3; otherwise, go to step S4.

[0040] S3, open the first solenoid valve 53, when the liquid level measured by the liquid level meter 59 is H w =0, close the first solenoid valve 53 and open the second solenoid valve 56 until H w =H max When N<N max When the first solenoid valve 53 and the second solenoid valve 56 are closed, step S5 is executed.

[0041] S4, turn off the turbidity sensor 58, and determine H w <H max Is it true? If H w <H max Then the second solenoid valve 56 is opened until H w =H max When H is reached, the second solenoid valve 56 is closed and step S5 is performed; if H w >H max Then directly execute step S5.

[0042] S5. Select the coolant interface Y according to the axial length L of the heated workpiece m , start the motor 12 to move the infrared thermometer 2 to the coolant interface Y m Place.

[0043] S6, open the coolant interface Y1 and the coolant interface Y m , the coolant is delivered to the coolant interface Y1 through the liquid pump 4 and the coolant is m outflow.

[0044] S7, determine the real-time coolant flow rate Q ≥ coolant flow rate lower limit Q min Is it established? If it is established, start the power supply 9 and execute step S8. Otherwise, check whether the cooling device works normally and then re-determine whether the real-time flow rate of the coolant Q is greater than the lower limit of the flow rate of the coolant Q. min Whether it is established, until it is established and execute step S8.

[0045] S8, real-time monitoring of coolant interface Y m The temperature T Ym , according to T YmSelect the coolant inlet and outlet ports and determine T Ym ≥T max3 If it is established, turn off the power supply, check whether the cooling device is working properly, and then return to step S7. Otherwise, determine whether T max2 <T Ym <T max3 Is it true? If so, execute step S81 according to the coolant interface number m. Otherwise, determine T max1 <T Ym <T max2 Is it true? If so, the solenoid valve R m Switch to liquid inlet state, coolant interface Y m Switch to the liquid inlet and execute step S82 according to the coolant interface number m; if not established, directly execute step S9.

[0046] Step S81 is: if m=2, increase the real-time coolant flow Q and execute step S9; if m>2, the odd-numbered solenoid valves are all switched to the liquid inlet state, and the corresponding coolant interfaces are switched to the liquid inlet, and the even-numbered solenoid valves are all switched to the liquid outlet state, and the corresponding cooling interfaces are switched to the liquid outlet, and execute step S9.

[0047] Step S82 is: if m=2, solenoid valves R3~R n All are switched to the liquid outlet state, coolant interface Y3~Y n Switch to the liquid outlet, execute step S9, if m>2, solenoid valves R2~R m-1 All are switched to the liquid outlet state, coolant interface Y2~Y m-1 Switch to the liquid outlet and execute step S9.

[0048] S9, turn on the power supply 9, and determine whether the heated workpiece meets the heat treatment requirements. If yes, execute step S10, otherwise return to execute step S7.

[0049] S10, turn off power 9, remove the heated workpiece, and determine T Ym <T max1 Is it true? If so, close the liquid pump 4 and all electromagnetic valves 6. Otherwise, keep the current open and closed state of the electromagnetic valve 6 and continue cooling until T Ym <T max1 , the induction heating ends.

[0050] like Figure 2 to Figure 4As shown, a cooling device for a multi-turn coil includes a slide assembly 1, an infrared thermometer 2, a controller 3, a liquid pump 4, a cooling supply assembly 5, a solenoid valve 6, a coil 7 and a power supply 9. The cooling supply assembly 5 includes a liquid tank 51, a round-shaped partition 57, a turbidity sensor 58, a liquid level meter 59, a flow meter 513, a first solenoid valve 53 and a second solenoid valve 56. The temperature of the coolant rises after flowing through the coil 7. A round-shaped partition 57 is arranged in the liquid tank 51 to form a round-shaped liquid path. A wire is provided at the first end of the round-shaped liquid path. The coil liquid inlet 55 and the liquid tank discharge port 54 are provided, and the second end of the circular liquid path is provided with a coil liquid return port 510 and a liquid tank liquid inlet 52; a liquid level meter 59 and a turbidity sensor 58 are arranged at the coil liquid inlet 55, the liquid level meter 59 controls the amount of coolant, the turbidity sensor 58 detects the turbidity of the coolant, the flow meter 513 is connected to the coil liquid inlet channel 511, the first solenoid valve 53 is connected to the liquid tank discharge port 54, the first solenoid valve 53 controls the discharge of coolant, and the second solenoid valve 56 is connected to the liquid tank liquid inlet 52. The slide assembly 1 includes a temperature measuring bracket 11, a motor 12, a lead screw 13, a distance measuring bracket 14 and a distance measuring sensor 15. The infrared thermometer 2 is arranged on the temperature measuring bracket 11, and the distance measuring sensor 15 is arranged on the distance measuring bracket 14. The controller 3 is connected to the motor 12, the distance measuring sensor 15, the infrared thermometer 2, the liquid pump 4, the first solenoid valve 53, the second solenoid valve 56, the turbidity sensor 58, the liquid level meter 59, the flow meter 513, the solenoid valve 6, and the power supply 9 through electrical signals. The first solenoid valve 53 and the second solenoid valve 56 in the cooling supply assembly 5 are both two-position two-way valves. When the valve core is in the middle position, the liquid circuit is closed, and when the valve core is actuated, the liquid circuit is opened. The solenoid valve 6 is a three-position three-way valve. When the valve core is in the middle position, the liquid circuit is closed. A plurality of coolant interfaces 71 are provided on the coil 7, and the coolant interfaces 71 are numbered in sequence as [Y1, Y2,…, Y m , …, Y n ], the cooling liquid interface 71 is provided with a solenoid valve 6, and the solenoid valves 6 are numbered in sequence as [R1, R2, ..., R m , …, R n ], the distance D between adjacent coolant interfaces 71 is less than D max The coolant interface 71 is connected to the coil liquid inlet channel 511 and the coil liquid return channel 512 through the solenoid valve 6, respectively, to realize automatic monitoring and judgment of the coolant remaining amount and liquid quality, and automatically replace the coolant. During induction heating, the circulation state of the coolant is adjusted in real time according to the change of the temperature of the coil 7 to ensure the cooling effect of the coil 7.

[0051] The overheat protection method and cooling device for a multi-turn coil of the present invention are further described below in conjunction with the embodiments:

[0052] To ensure the cooling rate, limit T2 ≤ the first warning temperature T max1 In this embodiment, T max1=60℃, T1=1500℃, T0=25℃, A s =1m 2 ,σ=5.67×10-8W / (m 2 ·K 4 ), surface emissivity ε = 0.1, coolant density ρ = 1000 kg / m 3 , the specific heat capacity of the coolant c p =4184J / (kg·K), coolant flow rate Q=0.01m 3 / s is substituted into the formula to obtain the maximum value D of the distance D between two adjacent coolant interfaces 71 along the winding direction of the coil 7 max ≤3.29m.

[0053] After the coolant interface 71 is determined, a solenoid valve 6 is provided at each coolant interface 71, and the solenoid valves 6 are numbered in sequence as [R1, R2, ..., R m , …, R n ];like Figure 3 As shown, each solenoid valve 6 is connected to the first end of the coil inlet channel 511 and the first end of the coil return channel 512, the second end of the coil inlet channel 511 is connected to the liquid pump, and the second end of the coil return channel 512 is connected to the coil return port 510. During induction heating, the circulation state of the coolant will be dynamically adjusted according to the temperature change of the coil 7. Therefore, the solenoid valves 6 set at the coolant interface 71 are all three-position three-way valves. When the valve core is in the middle position, the liquid circuit is closed. When the valve core is in motion, the corresponding coolant interface 71 is switched to the liquid inlet or the liquid outlet.

[0054] The overheat protection method and cooling device for a multi-turn coil of the present invention adopt an effective heat dissipation and cooling structure, combined with a system for dynamically monitoring the state of the coolant, to establish a coil temperature control and management mechanism to prevent the coil from overheating due to long-term heating, mismatch between the coil and the workpiece, and insufficient cooling hydraulic pressure, and effectively prevent the coolant quality from deteriorating due to industrial dust and metal corrosion, ensuring that the coil 7 continues to operate stably within a safe temperature range, thereby extending the life of the equipment and improving the reliability of the cooling system.

[0055] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for overheat protection of a multi-turn coil, characterized in that: It includes the following steps: S1. Determine the upper limit turbidity N of the coolant according to process requirements max , determine the length L of the heated workpiece and set the first warning temperature T max1 , Second warning temperature T max2 and the third warning temperature T max3 , determine the upper limit of the liquid level H max , real-time measurement of turbidity N; S2. Determine N≥N max Is it true? If so, go to step S3; otherwise, go to step S4; S3, open the first solenoid valve, when the liquid level measured by the level gauge is H w =0, close the first solenoid valve and open the second solenoid valve until H w =H max When N<N max When the first solenoid valve and the second solenoid valve are closed, step S5 is executed; S4, turn off the turbidity sensor and judge H w <H max Is it true? If H w <H max Then open the second solenoid valve until H w =H max When the second solenoid valve is closed, step S5 is executed; if H w >H max Then directly execute step S5; S5. Select the coolant interface Y according to the axial length L of the heated workpiece m , start the motor to move the infrared thermometer to the coolant interface Y m Department; S6, open the coolant interface Y1 and the coolant interface Y m , the coolant is delivered to the coolant interface Y1 through the liquid pump and the coolant is m outflow; S7, determine the real-time coolant flow rate Q ≥ coolant flow rate lower limit Q min If yes, start the power supply and execute step S8. Otherwise, check whether the cooling device works normally and then re-determine whether the real-time flow rate of the coolant Q is greater than the lower limit of the flow rate of the coolant Q. min Is it established, until it is established and execute step S8; S8, real-time monitoring of coolant interface Y m The temperature T Ym , according to T Ym Select the coolant inlet and outlet ports and determine T Ym ≥T max3 If it is established, turn off the power supply, check whether the cooling device is working properly, and then return to step S7. Otherwise, determine whether T max2 <T Ym <T max3 Is it true? If so, execute step S81 according to the coolant interface number m. Otherwise, determine T max1 <T Ym <T max2 Is it true? If so, the solenoid valve R m Switch to liquid inlet state, coolant interface Y m Switch to the liquid inlet, and execute step S82 according to the coolant interface number m. If not, directly execute step S9; S9, turn on the power supply, determine whether the heated workpiece meets the heat treatment requirements, if yes, execute step S10, otherwise return to execute step S7; S10, turn off the power, remove the heated workpiece, and determine T Ym <T max1 Is it true? If so, close the liquid pump and all solenoid valves. Otherwise, keep the current solenoid valve open and closed and continue cooling until T Ym <T max1 , the induction heating ends.

2. The overheat protection method for a multi-turn coil according to claim 1, characterized in that: Step S81 is: if m=2, increase the real-time coolant flow Q and execute step S9; if m>2, the odd-numbered solenoid valves are all switched to the liquid inlet state, and the corresponding coolant interfaces are switched to the liquid inlet, and the even-numbered solenoid valves are all switched to the liquid outlet state, and the corresponding cooling interfaces are switched to the liquid outlet, and execute step S9.

3. The overheat protection method for a multi-turn coil according to claim 1, characterized in that: Step S82 is: if m=2, solenoid valves R3~R n All are switched to the liquid outlet state, coolant interface Y3~Y n Switch to the liquid outlet, execute step S9, if m>2, solenoid valves R2~R m-1 All are switched to the liquid outlet state, coolant interface Y2~Y m-1 Switch to the liquid outlet and execute step S9.

4. A cooling device for overheat protection of a multi-turn coil according to claim 1, characterized in that: It includes a slide assembly, an infrared thermometer, a controller, a liquid pump, a cooling supply assembly, a solenoid valve and a power supply. The cooling supply assembly includes a liquid tank, a round-shaped partition, a turbidity sensor, a liquid level meter, a flow meter, a first solenoid valve and a second solenoid valve. The liquid tank is provided with the round-shaped partition to form a round-shaped liquid path. The first end of the round-shaped liquid path is provided with a coil liquid inlet and a liquid tank discharge port. The second end of the round-shaped liquid path is provided with a coil liquid return port and a liquid tank liquid inlet. The liquid level meter and the turbidity sensor are arranged at the coil liquid inlet. The flow meter is connected to the coil liquid inlet channel. The first solenoid valve is connected to the liquid tank discharge port. The second solenoid valve is connected to the liquid tank liquid inlet.

5. The cooling device for a multi-turn coil according to claim 4, characterized in that: The slide assembly includes a temperature measuring bracket, a motor, a lead screw, a distance measuring bracket and a distance measuring sensor. The infrared thermometer is arranged on the temperature measuring bracket, and the distance measuring sensor is placed on the distance measuring bracket. The controller is connected to the motor, the distance measuring sensor, the infrared thermometer, the liquid pump, the first solenoid valve, the second solenoid valve, the turbidity sensor, the liquid level meter, the flow meter, the solenoid valve, and the power supply through electrical signals.

6. The cooling device for a multi-turn coil according to claim 4, characterized in that: The coil is provided with a plurality of coolant interfaces, each of which is provided with the solenoid valve, and the coolant interfaces are respectively connected with the coil liquid inlet channel and the coil liquid return channel through the solenoid valve.

7. The cooling device for a multi-turn coil according to claim 4, characterized in that: The first solenoid valve and the second solenoid valve in the cooling supply assembly are both two-position two-way valves. When the valve core is in the middle position, the liquid circuit is closed, and when the valve core is in motion, the liquid circuit is opened.

8. The cooling device for a multi-turn coil according to claim 4, characterized in that: The solenoid valve is a three-position three-way valve, and the liquid circuit is closed when the valve core is in the middle position.

9. The cooling device for a multi-turn coil according to claim 6, characterized in that: The distance D between adjacent coolant interfaces is less than the maximum distance D max , and the maximum spacing D max The determination method is: establish the influence equation of the length L of the heated workpiece on the temperature T2 at the coil outlet, set the maximum value of the temperature T2 at the coil outlet to obtain D max , the influence equation of T2 and L is: Where T1 is the maximum heating temperature of the heated workpiece, T0 is the temperature at the coil entrance, σ is the Stefan-Boltzmann constant, ε is the surface emissivity, and A is s is the coil surface area, ρ is the density of the coolant, c p is the specific heat capacity of the coolant, Q min This is the lower limit of coolant flow.

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