Accurate temperature control method and system of high-temperature argon atmosphere heating furnace

Abstract

The present application belongs to the technical field of industrial heating, and particularly relates to a precise temperature control method and system for a high-temperature argon atmosphere heating furnace. The precise temperature control method for the high-temperature argon atmosphere heating furnace comprises: setting a left and right wall main heating loop, a rear wall main and auxiliary heating loop, and a bottom auxiliary heating loop in the heating furnace; setting a temperature control and measurement unit on the upper part of the rear wall of the heating furnace; initializing and preheating the heating furnace; establishing a power utilization rate dynamic adjustment system; switching to a constant temperature firing stage in the heating stage, and adjusting the overall power utilization rate to 32% to 42%. The temperature data of the temperature control and measurement unit located on the upper part of the rear wall is taken as the main control temperature reference, and the power utilization rate is controlled. Compared with the existing scheme which relies on single-point temperature measurement and fixed power output, the method of the present application has substantial improvements in temperature field uniformity, energy consumption control, and continuous operation reliability.

Description

Technical Field

[0001] This invention belongs to the field of industrial heating technology, specifically relating to a precise temperature control method and system for a high-temperature argon atmosphere heating furnace. Background Technology

[0002] While existing high-temperature argon atmosphere heating furnaces can utilize the inert protection of argon gas to achieve oxidation-resistant firing, the core technical challenges remain: precise control of the target temperature of 550℃, uniformity of the furnace temperature field, and a balance between energy consumption and stability, which have long remained unresolved. Most existing equipment relies on single-point or limited thermocouple temperature measurement, failing to cover critical areas such as the left and right walls, rear wall, and bottom of the furnace. In particular, the rear wall jacket gap is ≥180mm, resulting in significant heat loss and often leading to lower temperatures in this area, with an overall temperature field deviation exceeding ±5℃, severely impacting the consistency of material firing.

[0003] Furthermore, the fixed power distribution of the main and auxiliary heating circuits prevents dynamic adjustment based on different operating conditions such as heating and temperature control, as well as variations in regional heat loss. This results in a heating rate deviating from the preset value of 250℃ / h, while power redundancy and waste occur during the temperature control phase. The heating, atmosphere, and fan controls are independent and lack coordination; fluctuations in argon flow and unreasonable fan speeds exacerbate temperature unevenness. The fault protection mechanism is inadequate, lacking tiered protection against overheating, thermocouple failures, or heating element power attenuation, making it difficult to meet the mass production requirement of 150 hours of continuous trouble-free operation. Overall energy consumption is also high due to the lack of power optimization based on operating conditions and coordinated control with the fan and insulation structure. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies, such as incomplete coverage of temperature measurement points, inability to dynamically adapt power, lack of linkage between multiple systems, and insufficient protection against abnormalities. It provides a precise temperature control method and system for a high-temperature argon atmosphere heating furnace that can achieve uniform temperature field across the entire area, self-adjustment of heating and constant temperature power, and coordinated control of heating atmosphere fans.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] As a first aspect, the present invention provides a precise temperature control method for a high-temperature argon atmosphere heating furnace, comprising the following:

[0007] Step 1: Set up the main heating circuits on the left and right walls, the main and auxiliary heating circuits on the rear wall, and the auxiliary heating circuit at the bottom inside the heating furnace; and set up a temperature control and measurement unit on the upper part of the rear wall of the heating furnace, and a monitoring and measurement unit on the lower part of the rear wall of the heating furnace.

[0008] Step 2: Initialize and preheat the heating furnace, and set the basic and control parameters of the heating furnace;

[0009] Step 3: Establish a dynamic power utilization rate adjustment system; use the temperature obtained by the temperature control and measurement unit as the main control temperature reference, and the temperature obtained by the monitoring and measurement unit as the monitoring temperature; control the power utilization rate of the left and right wall main heating circuits, the rear wall main and auxiliary heating circuits, and the bottom auxiliary heating circuit;

[0010] Step 4: During the heating phase, control the main heating circuits of the left and right walls, the main and auxiliary heating circuits of the rear wall, and the auxiliary heating circuit at the bottom to operate at a power utilization rate of 75% to 85%.

[0011] Step 5: When the main control temperature reaches the set heating threshold, switch to the constant temperature firing stage, that is, adjust the overall power utilization rate to 32%~42%;

[0012] Step 6: Complete the firing control through graded abnormality protection control.

[0013] Specifically, the basic parameters of the heating furnace include at least one of the following: set heating temperature, low temperature threshold, over-temperature threshold, and over-temperature recovery threshold; the control parameters include at least one of the following: set heating rate, heating time, and initial argon flow rate.

[0014] Specifically, during the heating phase, the monitored temperature data is acquired in real time and compared with the main control temperature; if the monitored temperature deviates from the main control temperature by 4℃ to 5℃, the power of the bottom auxiliary heating circuit is increased or decreased by 8% to 12%; during the heating phase, the argon gas flow rate is 15m³ / h to 25m³ / h.

[0015] Specifically, the isothermal firing stage includes the following operations:

[0016] If the main control temperature is lower than the low temperature threshold, increase the power of the main and auxiliary heating circuits of the rear wall by 8% to 12%, and simultaneously fine-tune the power of the main heating circuits of the left and right walls by 5% to 8%.

[0017] If the main control temperature is higher than the over-temperature threshold, reduce the power of the rear wall main and auxiliary heating circuits by 8% to 12%, and then reduce the power of the left and right wall main heating circuits by 5% to 8%.

[0018] If the monitored temperature deviates from the temperature data value in the main and auxiliary heating circuits of the rear wall by ≥2.5℃, the power of the bottom auxiliary heating circuit is finely adjusted, and the adjustment range is 50% to 100% of the current power of the bottom auxiliary heating circuit.

[0019] Specifically, the power distribution ratio of the left and right wall main heating circuits, the rear wall main and auxiliary heating circuits, and the bottom auxiliary heating circuit is as follows: the left and right wall main heating circuits account for 55.6% to 76.9% of the total power, the rear wall main and auxiliary heating circuits account for 0% to 27.8%, and the bottom auxiliary heating circuits account for 16.7% to 23.1%.

[0020] Specifically, in step three, the power utilization rate during the heating stage is dynamically adjusted according to the actual heating rate. If the actual heating rate is less than the set heating rate, the power utilization rate is increased to 80% to 85%; if the actual heating rate is greater than the set heating rate, the power utilization rate is decreased to 75% to 80%.

[0021] Specifically, step two also includes establishing an argon gas circulation system and an argon gas flow control system; the argon gas circulation system and the argon gas flow control system dynamically adjust the argon gas circulation and argon gas flow based on the current power utilization rate, the temperature data of the temperature control and temperature measurement unit, and the temperature data of the monitoring and temperature measurement unit.

[0022] During the constant temperature firing stage, when the deviation between the main control temperature and the monitoring temperature is ≥2℃, the speed of the high temperature circulating fan is increased by 10% to 20%.

[0023] Specifically, the hierarchical anomaly protection control includes:

[0024] When any temperature obtained by the temperature control and measurement unit, the monitoring and measurement unit, or the auxiliary temperature measurement unit exceeds the over-temperature threshold, the entire heating circuit will stop heating and an alarm will be triggered.

[0025] If the temperature control and measurement unit has no temperature feedback or the data is abnormal, the monitoring temperature obtained by the monitoring and measurement unit shall be used as the main control temperature; and the total heating power shall be limited to no more than 70% of the rated power.

[0026] If the monitoring temperature measurement unit malfunctions, it will not affect the main control temperature, but will only trigger the bottom auxiliary heating circuit to stop heating.

[0027] As a second aspect, the present invention also provides a precise temperature control system for a high-temperature argon atmosphere heating furnace, comprising: a main control module; a temperature measuring module, a heating control module, a fan control module, a gas path control module, and an abnormal protection module electrically connected to the main control module; and main heating circuits on the left and right walls, main and auxiliary heating circuits on the rear wall, and auxiliary heating circuits at the bottom, all distributed within the heating furnace.

[0028] Temperature measuring modules are distributed inside the heating furnace to obtain the temperature inside the heating furnace in real time;

[0029] The heating control module adjusts the power of the main heating circuits of the left and right walls, the main and auxiliary heating circuits of the rear wall, and the auxiliary heating circuit at the bottom through solid-state relays, thereby dynamically adjusting the power utilization and power distribution.

[0030] The gas path control module is used to regulate the flow rate of argon gas entering the heating furnace; the abnormal protection module is used for abnormal protection of the heating furnace.

[0031] Specifically, the temperature measuring module includes a temperature control and measuring unit disposed on the upper part of the rear wall of the heating furnace and a temperature monitoring and measuring unit disposed on the lower part of the rear wall of the heating furnace;

[0032] Both the temperature control and temperature measurement unit and the monitoring and temperature measurement unit use K-type thermocouples.

[0033] Specifically, the anomaly protection module includes:

[0034] An audible and visual alarm is electrically connected to the main control module.

[0035] The power-off relay receives the control signal from the main control module and is connected in series with the main heating circuits of the left and right walls, the main and auxiliary heating circuits of the rear wall, and the auxiliary heating circuit at the bottom.

[0036] A backup temperature control unit is electrically connected to the monitoring and measurement unit; it automatically starts when the temperature control and measurement unit fails, and uses the temperature obtained by the monitoring and measurement unit as the main control temperature reference.

[0037] Specifically, the gas path control module includes:

[0038] Flow control unit;

[0039] A pressure sensor and a zirconium oxide oxygen content detector are installed in the argon gas communication circuit.

[0040] And an electrically controlled butterfly valve installed on the argon gas connection line for controlling the argon gas connection line;

[0041] The flow control unit, pressure sensor, zirconium oxide oxygen content detector, and electrically controlled butterfly valve are all connected to the main control module via signal transmission.

[0042] Specifically, the main heating circuits of the left and right walls include a main heating circuit of the left arm and a main heating circuit of the right arm; both the main heating circuit of the left arm and the main heating circuit of the right arm include six heating tubes; the main and auxiliary heating circuits of the rear wall include six heating tubes, and the auxiliary heating circuit of the bottom includes three heating tubes.

[0043] The beneficial effects of the precise temperature control method and system for a high-temperature argon atmosphere heating furnace of the present invention are as follows:

[0044] This invention achieves temperature distribution detection within the furnace by arranging a temperature control and measurement unit on the upper part of the rear wall and a monitoring and measurement unit on the lower part of the rear wall, combined with four independent circuits: the main heating circuits on the left and right walls, the main and auxiliary heating circuits on the rear wall, and the auxiliary heating circuit at the bottom. It also establishes a dynamic power utilization adjustment system. The temperature data from the temperature control and measurement unit located on the upper part of the rear wall serves as the main control temperature reference, while the temperature data acquired by the monitoring and measurement unit serves as the monitoring temperature. This system controls the power utilization of the main heating circuits on the left and right walls, the main and auxiliary heating circuits on the rear wall, and the auxiliary heating circuit at the bottom. Compared with existing schemes that rely on single-point temperature measurement and fixed power output, this invention provides substantial improvements in temperature field uniformity, energy consumption control, and continuous operation reliability.

[0045] Specifically, through dynamic adjustment of power utilization, the heating and constant-temperature stages are controlled within the ranges of 75%–85% and 32%–42%, respectively, allowing for further fine-tuning based on the actual heating rate. During heating, the power utilization automatically increases or decreases with deviations from the rate, avoiding the large fluctuations in heating rate or power redundancy waste during the constant-temperature stage caused by fixed power in traditional equipment. Simultaneously, in the power distribution ratio of the three circuits (left and right walls, rear wall, and bottom), the main heating circuits of the left and right walls account for 55.6%–76.9% of the total power, the main and auxiliary heating circuits of the rear wall account for 0–27.8%, and the auxiliary heating circuit of the bottom accounts for 16.7%–23.1%. The main heating circuits of the left and right walls are prioritized, with the bottom and rear walls as auxiliary circuits. During the constant-temperature stage, the rear wall and left and right wall circuits are adjusted sequentially based on the deviation of the main control temperature from the low-temperature or over-temperature threshold, ensuring both response speed and preventing over-adjustment oscillations. Furthermore, it integrates a high-temperature circulating fan and an argon gas path system, and sets up a graded abnormal protection mechanism, which solves the problems of poor temperature field uniformity, high energy consumption, and weak abnormal response capability of existing heating furnaces. It effectively improves the consistency of material calcination, reduces energy consumption, and ensures continuous and stable operation of the equipment, thereby adapting to mass production needs. Attached Figure Description

[0046] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0047] Figure 1 This is a flowchart of the precise temperature control method for the heating furnace of the present invention.

[0048] Figure 2 This is a block diagram of the precise temperature control system for the heating furnace of the present invention.

[0049] Figure 3 This is a schematic diagram showing the location of the temperature control and monitoring units on the heating furnace.

[0050] In the diagram: 1. Main control module; 2. Temperature measurement module; 21. Temperature control and measurement unit; 22. Monitoring and measurement unit; 3. Heating control module; 4. Fan control module; 5. Gas path control module; 6. Abnormal protection module; 61. Audible and visual alarm; 62. Power failure relay; 63. Backup temperature control unit; 7. Heating furnace; 8. Main heating circuits for left and right walls; 81. Main heating circuit for left wall; 82. Main heating circuit for right wall; 9. Main and auxiliary heating circuits for rear wall; 10. Auxiliary heating circuit for bottom; 11. Solid-state relay. Detailed Implementation

[0051] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0052] like Figures 1-3 The specific embodiment of the precise temperature control method for a high-temperature argon atmosphere heating furnace of the present invention shown includes the following:

[0053] Step 1: Set up the main heating circuits 8 on the left and right walls, the main and auxiliary heating circuits 9 on the rear wall, and the auxiliary heating circuit 10 at the bottom inside the heating furnace 7; and set up the temperature control and measurement unit 21 on the upper part of the rear wall of the heating furnace 7, and set up the monitoring and measurement unit 22 on the lower part of the rear wall of the heating furnace 7.

[0054] Step 2: Initialize and preheat the heating furnace 7, and set the basic parameters and control parameters of the heating furnace 7;

[0055] Step 3: Establish a dynamic power utilization rate adjustment system; take the temperature obtained by the temperature control and measurement unit 21 as the main control temperature reference, and the temperature data obtained by the monitoring and measurement unit 22 as the monitoring temperature to control the power utilization rate of the main heating circuit 8 of the left and right walls, the main and auxiliary heating circuit 9 of the rear wall, and the auxiliary heating circuit 10 at the bottom.

[0056] Step 4: During the heating phase, control the main heating circuit 8 of the left and right walls, the main and auxiliary heating circuit 9 of the rear wall, and the auxiliary heating circuit 10 of the bottom to operate at a power utilization rate of 75% to 85%.

[0057] Step 5: When the main control temperature reaches the set heating threshold, switch to the constant temperature firing stage, that is, adjust the overall power utilization rate to 32%~42%;

[0058] Step 6: Complete the firing control through graded abnormality protection control.

[0059] In this embodiment, the main heating circuits 8 for the left and right walls include a main heating circuit 81 for the left wall and a main heating circuit 82 for the right wall. This embodiment achieves temperature distribution detection within the furnace by arranging a temperature control and measurement unit 21 on the upper part of the rear wall of the furnace 7 and a monitoring and measurement unit 22 on the lower part of the rear wall of the furnace 7. Combined with four independent circuits—the main heating circuits 8 for the left and right walls, the main and auxiliary heating circuits 9 for the rear wall, and the auxiliary heating circuit 10 for the bottom—it establishes a dynamic power utilization adjustment system. The temperature data from the temperature control and measurement unit 21 located on the upper part of the rear wall serves as the main control temperature reference, guiding the entire temperature control logic. The temperature data acquired by the monitoring and measurement unit 22 is the monitoring temperature and does not participate in the main temperature control; it serves as temperature field monitoring and anomaly feedback, assisting in judging the uniformity of the temperature field above and below the furnace and providing a reference for power fine-tuning. Compared with existing schemes that rely on single-point temperature measurement and fixed power output, this method substantially improves the uniformity of the temperature field, energy consumption control, and continuous operation reliability by controlling the power utilization of the main heating circuits 8 for the left and right walls, the main and auxiliary heating circuits 9 for the rear wall, and the auxiliary heating circuit 10 for the bottom.

[0060] This embodiment takes a heating condition of 550℃ as an example. The main heating circuits 8 for the left and right walls include a left arm main heating circuit and a right arm main heating circuit. Both the left and right arm main heating circuits include six heating tubes. The rear wall main and auxiliary heating circuits 9 include six heating tubes, and the bottom auxiliary heating circuit 10 includes three heating tubes. A total of 21 heating tubes are used. In a preferred embodiment, the 21 heating tubes are SUS310SU type heating tubes with a total power of 108kW. There are 12 heating tubes on the left and right walls, each with a power of 5kW; 6 on the rear wall, each with a power of 5kW; and 3 on the bottom, each with a power of 6kW.

[0061] In this embodiment, the basic parameters of the heating furnace 7 in step two include at least one of the following: set heating temperature, low temperature threshold, over-temperature threshold, and over-temperature recovery threshold. The control parameters include at least one of the following: set heating rate, heating time, and initial argon flow rate. Specifically, the basic parameters of the heating furnace 7 are: set heating temperature 550℃, room temperature reference 25℃, temperature difference ΔT = 525℃, low temperature threshold 548℃, over-temperature threshold 558℃, over-temperature recovery threshold 552℃, and oxygen content in the furnace ≤ 8ppm; the control parameters include a heating rate of 250℃ / h and a heating time of 2.1h.

[0062] In this embodiment, both the temperature control and temperature measurement unit 21 and the monitoring and temperature measurement unit 22 use K-type thermocouples. The temperature measurement range of the K-type thermocouple is 0 to 800℃, with an accuracy of ±0.5℃.

[0063] In step four, during the heating stage, the temperature data of the monitoring temperature measurement unit 22 is acquired in real time, i.e., the monitoring temperature, and compared with the main control temperature. If the temperature data of the monitoring temperature measurement unit 22 deviates from the main control temperature by 4℃~5℃, the power of the rear wall main and auxiliary heating circuit 9 is increased or decreased by 8%~12%. During the heating stage, the argon flow rate is 15m³ / h~25m³ / h.

[0064] In this embodiment, the temperature control and measurement unit 21 is used as the main temperature control reference, and the monitoring and measurement unit 22 is linked to link the four heating circuits, control the heating tubes in each area to operate at a power utilization rate of 75% to 85%, and ensure that the heating rate is stable at 250℃ / h.

[0065] In detail, the power utilization rate during the heating stage is dynamically adjusted according to the actual heating rate. If the actual heating rate is less than the set heating rate, the power utilization rate is increased to 80% to 85%; if the actual heating rate is greater than the set heating rate, the power utilization rate is decreased to 75% to 80%.

[0066] Step five, the isothermal firing stage, includes the following operations:

[0067] If the main control temperature is lower than the low temperature threshold, increase the power of the rear wall main and auxiliary heating circuit 9 by 8% to 12%, and simultaneously fine-tune the power of the left and right wall main heating circuits 8 by 5% to 8%.

[0068] If the main control temperature is higher than the over-temperature threshold, reduce the power of the rear wall main and auxiliary heating circuit 9 by 8% to 12%, and then reduce the power of the left and right wall main heating circuits 8 by 5% to 8%.

[0069] If the monitored temperature deviates from the temperature data value in the main and auxiliary heating circuit 9 of the rear wall by ≥2.5℃, the power of the bottom auxiliary heating circuit 10 is finely adjusted, and the adjustment range is 50% to 100% of the current power of the bottom auxiliary heating circuit 10.

[0070] During the constant temperature phase, when the main control temperature reaches 550℃, the system switches to the constant temperature phase and adjusts the power utilization rate of the left and right wall main heating circuits 8, the rear wall main and auxiliary heating circuits 9, and the bottom auxiliary heating circuit 10 to 32%–42%. If the average temperature is lower than the low temperature threshold of 548℃, the power of the rear wall main and auxiliary heating circuits 9 is increased by 8%–12%, and the power of the left and right wall main heating circuits 8 is adjusted by 5%–8%. If the average temperature is higher than the over-temperature threshold of 552℃, the power of the rear wall main and auxiliary heating circuits 9 is reduced by 8%–12%, and the power of the left and right wall main heating circuits 8 is reduced by 5%–8%. If the monitored temperature deviates from the temperature data value in the rear wall main and auxiliary heating circuits 9 by ≥2.5℃, the power of the bottom auxiliary heating circuit 10 is adjusted. In this practical example, the power utilization rate during the constant temperature stage is dynamically adjusted according to the furnace door opening frequency and ambient temperature to ensure matching with the steady-state thermal balance power of 29.32kW.

[0071] In this embodiment, the power distribution ratio of the left and right wall main heating circuits 8, the rear wall main and auxiliary heating circuits 9, and the bottom auxiliary heating circuit 10 is as follows: the left and right wall main heating circuits 8 account for 55.6% to 76.9% of the total power, the rear wall main and auxiliary heating circuits 9 account for 0% to 27.8%, and the bottom auxiliary heating circuit 10 accounts for 16.7% to 23.1%. In a preferred embodiment, the right wall main heating circuit 8 accounts for 64% of the total power, the rear wall main and auxiliary heating circuits 9 account for 26%, and the bottom auxiliary heating circuit 10 accounts for 18.7%. That is, based on the coordinated control of main and auxiliary heating, the basic ratio of the left and right wall main heating circuits 8 accounting for 64% of the total power, the rear wall main and auxiliary heating circuits 9 accounting for 26%, and the bottom auxiliary heating circuit 10 accounting for 18.7% of the total power is maintained.

[0072] By dynamically adjusting the power utilization rate, the heating and constant-temperature stages are controlled within the ranges of 75%–85% and 32%–42%, respectively, allowing for further fine-tuning based on the actual heating rate. During heating, the power utilization rate automatically increases or decreases as the rate deviates, avoiding the large fluctuations in the heating rate or the power redundancy waste during the constant-temperature stage caused by fixed power in traditional equipment. Simultaneously, in the power distribution ratio of the three circuits (left and right walls, rear wall, and bottom), the main heating circuit 8 of the left and right walls accounts for 55.6%–76.9% of the total power, the main and auxiliary heating circuit 9 of the rear wall accounts for 0–27.8%, and the auxiliary heating circuit 10 of the bottom accounts for 16.7%–23.1%. The main heating circuit 8 of the left and right walls is the primary source, with the bottom and rear walls as secondary sources. During the constant-temperature stage, the rear wall heating circuit and the main heating circuits of the left and right walls are adjusted sequentially based on the deviation of the main control temperature from the low-temperature threshold or the over-temperature threshold, ensuring both response speed and preventing over-adjustment oscillation. Furthermore, it is linked with the high-temperature circulating fan and argon gas path system, and is equipped with a graded abnormal protection mechanism, which solves the problems of poor temperature field uniformity, high energy consumption and weak abnormal response capability of the existing heating furnace 7, improves the consistency of material burning, reduces energy consumption, ensures continuous and stable operation of equipment, and adapts to mass production needs.

[0073] It should be further explained that, in step two of this embodiment, an argon gas circulation system and an argon gas flow control system are also established. These systems dynamically adjust the argon gas circulation and flow rate based on the current power utilization rate, temperature data from the temperature control and measurement unit 21, and temperature data from the monitoring and measurement unit 22. During the isothermal firing stage, when the deviation between the main control temperature and the monitoring temperature is ≥2℃, the speed of the high-temperature circulating fan is increased by 10%–20%. In this embodiment, based on the 550℃ firing requirement, the argon gas flow rate is stabilized at 15–25 m³ / h to ensure a stable atmosphere inside the furnace, with an oxygen content ≤8 ppm, thus guaranteeing the firing quality of the solid electrolyte.

[0074] During the constant temperature firing stage, when the deviation between the main control temperature and the temperature obtained by the monitoring and measurement unit 22 is ≥2℃, the speed of the high temperature circulating fan is increased by 10% to 20% to enhance argon circulation and assist in uniform temperature field. During the heating stage, the speed of the high temperature circulating fan is dynamically adjusted according to the temperature rise rate to balance heating efficiency and temperature field uniformity.

[0075] The high-temperature circulating fan in this embodiment is frequency-controlled, with an adjustable speed of 0 to 2900 r / min, a standard air volume of 3100 m³ / h, and a standard air pressure of 220 Pa.

[0076] The graded abnormal protection control in this embodiment includes: when any temperature obtained by the temperature control and temperature measurement unit 21 or the monitoring and temperature measurement unit 22 exceeds the over-temperature threshold, all heating circuits are triggered to stop heating and an alarm is triggered; if the temperature control and temperature measurement unit 21 has no temperature feedback or the data is abnormal, the data of the monitoring and temperature measurement unit 22 is used as the main control temperature; and the total heating power is limited to no more than 70% of the rated power; if the monitoring and temperature measurement unit 22 fails, it does not affect the main control temperature, and only the bottom auxiliary heating circuit 10 is triggered to stop heating.

[0077] To ensure the safety of equipment and materials, multiple abnormal protection logics are set up. Based on the temperature data obtained by the temperature control and measurement unit 21 and the monitoring and measurement unit 22, when the temperature collected by the temperature control and measurement unit 21 exceeds 558℃, which is the over-temperature threshold, the heating tubes in all areas are immediately powered off, and an audible and visual alarm is issued. The high-temperature circulating fan keeps running at high speed until the temperature drops below 552℃, at which point heating is automatically restored and the power is adjusted.

[0078] If the temperature control and measurement unit 21 malfunctions, such as no temperature feedback or abnormal data, the backup monitoring mode is activated. Based on the data from the monitoring and measurement unit 22 below the rear wall, the total heating power is limited to no more than 70% of the rated power to ensure that the temperature does not exceed the limit and the firing progress is not affected. If the monitoring and measurement unit 22 below the rear wall malfunctions, it will not affect the main control temperature. Only the power of the bottom auxiliary heating circuit 10 will be suspended, and the temperature will continue to be controlled by the temperature control and measurement unit 21 to ensure the safety of firing at 550℃.

[0079] The present invention also provides a precise temperature control system for a high-temperature argon atmosphere heating furnace 7, comprising: a main control module 1; a temperature measuring module 2, a heating control module 3, a fan control module 4, a gas path control module 5, and an abnormal protection module 6 electrically connected to the main control module 1; and a main heating circuit 8 on the left and right walls, a main and auxiliary heating circuit 9 on the rear wall, and a bottom auxiliary heating circuit 10 distributed within the heating furnace 7.

[0080] Temperature measurement module 2 is distributed inside heating furnace 7 and is used to acquire the temperature inside heating furnace 7 in real time; heating control module 3 adjusts the power of the main heating circuit 8 on the left and right walls, the main and auxiliary heating circuit 9 on the rear wall, and the auxiliary heating circuit 10 at the bottom through solid-state relay 11 to dynamically adjust the power utilization rate and power distribution; gas path control module 5 is used to adjust the flow rate of argon gas entering heating furnace 7; abnormal protection module 6 is used for abnormal protection of heating furnace 7.

[0081] In this embodiment, the main control module 1 adopts a Siemens S7-1200 PLC with a built-in preset control logic program. It is connected to the temperature measurement module 2, heating control module 3, fan control module 4, gas path control module 5, and abnormal protection module 6 via Ethernet or RS485 bus. The main control module 1 receives feedback signals from each module, executes control commands such as heating, constant temperature, linkage, and abnormal protection, and coordinates the collaborative work of each module to achieve fully automated and precise temperature control.

[0082] like Figure 3 As shown, the temperature measurement module 2 in this embodiment includes a temperature control and measurement unit 21 installed on the upper part of the rear wall of the heating furnace 7 and a monitoring and measurement unit 22 installed on the lower part of the rear wall of the heating furnace 7. The temperature data acquired by the monitoring and measurement unit 22 is used as reference data for power adjustment. The temperature control and measurement unit 21 is installed on the upper part of the rear wall at a distance of 300mm from the top, and the monitoring and measurement unit 22 is installed on the lower part of the rear wall at a distance of 300mm from the bottom. They are connected to the main control module 1 through a compensation wire and output a temperature signal.

[0083] The heating control module 3 is electrically connected to 21 heating tubes and is divided into four independent heating circuits: left wall, right wall, bottom wall, and rear wall. It receives control signals from the main control module 1 and dynamically adjusts the power distribution and utilization rate of each circuit. The heating control module 3 includes a heating control unit and analog input modules. The heating control unit uses a Siemens S7-1200 PLC, and the analog input modules are EM231 and EM232 analog input modules. The heating control unit receives control signals from the main control module 1 and adjusts the power of each circuit through solid-state relays 11 to achieve dynamic adjustment of power utilization and power distribution. The solid-state relays 11 are model SSR-40DA.

[0084] The fan control module 4 in this embodiment includes a fan drive unit and a frequency converter. The frequency converter is a Delta VFD015B43A frequency converter with an input voltage of AC380V and an output frequency of 0-50Hz. It can adjust the fan speed from 0 to 2900 r / min. The frequency converter is electrically connected to the high-temperature circulating fan, receives the speed control signal from the main control module 1, and feeds back the fan operating status to the main control module 1 to achieve closed-loop control.

[0085] The gas path control module 5 includes a flow control unit, a pressure sensor and a zirconia oxygen content detector installed in the argon gas connection path, and an electrically controlled butterfly valve installed in the argon gas connection path for controlling the argon gas connection path. The flow control unit, pressure sensor, zirconia oxygen content detector, and electrically controlled butterfly valve are all connected to the main control module 1 via signal connections. In a specific implementation, the flow control unit in this embodiment uses an MF5712 flow controller with a range of 0–30 m³ / h and an accuracy of ±1%. The pressure sensor uses a PT100 pressure sensor with a range of 0–0.1 MPa, and the zirconia oxygen content detector has a range of 0–100 ppm and an accuracy of ±1 ppm. Based on feedback signals, the main control module 1 controls the flow control unit to adjust the argon gas flow rate and controls the opening and closing of the electrically controlled butterfly valve to maintain a stable atmosphere inside the furnace.

[0086] The abnormal protection module 6 in this embodiment includes an audible and visual alarm 61, a power-off relay 62, and a backup temperature control unit 63. The audible and visual alarm 61 is electrically connected to the main control module 1. The power-off relay 62 receives the control signal from the main control module 1 and is connected in series with the main heating circuits 8 of the left and right walls, the main and auxiliary heating circuits 9 of the rear wall, and the auxiliary heating circuit 10 of the bottom. The backup temperature control unit 63 is electrically connected to the monitoring and measuring unit 22. When the temperature control and measuring unit 21 fails, it is automatically activated, and the temperature obtained by the monitoring and measuring unit 22 is used as the main control temperature reference.

[0087] The audible and visual alarm 61 is an LTE-1101 type audible and visual alarm 61, and the power-off relay 62 is a CJX2-1210 type power-off relay 62. The audible and visual alarm 61 is connected to the main control module 1 and emits an audible and visual alarm under abnormal operating conditions. The power-off relay 62 is connected in series with each heating circuit, receives the control signal from the main control module 1, and cuts off the power supply of the corresponding circuit when the temperature exceeds the limit. The backup temperature control unit 63 has a built-in preset program and is connected to the auxiliary temperature measuring thermocouple. It automatically starts when the temperature control and temperature measuring unit 21 fails, and uses the average value of the auxiliary temperature measurement on the back wall as the main control temperature reference.

[0088] When the control system of this embodiment is running, the main control module 1 obtains the temperature data of each area in the heating furnace 7 through the temperature measurement module 2, calculates the power adjustment value of each heating circuit according to the preset logic, and sends the control signal to the heating control module 3; at the same time, it links the fan control module 4 and the gas path control module 5 to adjust the fan speed and argon flow rate; the abnormal protection module 6 monitors the equipment operating status in real time, and triggers protection measures in a timely manner when an abnormality occurs to ensure the stable and accurate operation of the heating furnace 7.

[0089] It should be understood that the specific embodiments described above are for illustrative purposes only and are not intended to limit the scope of the invention. Obvious variations or modifications derived from the spirit of the invention are still within the protection scope of the invention.

Claims

1. A precise temperature control method for a high-temperature argon atmosphere heating furnace, characterized in that, Includes the following: Step 1: Set up the main heating circuit (8) on the left and right walls, the main and auxiliary heating circuit (9) on the rear wall and the auxiliary heating circuit (10) at the bottom in the heating furnace (7); and set up a temperature control and measurement unit (21) on the upper part of the rear wall of the heating furnace (7) and a monitoring and measurement unit (22) on the lower part of the rear wall of the heating furnace (7). Step 2: Initialize and preheat the heating furnace (7), and set the basic parameters and control parameters of the heating furnace (7); Step 3: Establish a dynamic power utilization rate adjustment system; take the temperature obtained by the temperature control and measurement unit (21) as the main control temperature reference, and the temperature obtained by the monitoring and measurement unit (22) as the monitoring temperature; control the power utilization rate of the left and right wall main heating circuit (8), the rear wall main and auxiliary heating circuit (9) and the bottom auxiliary heating circuit (10); Step 4: During the heating stage, control the main heating circuit (8) of the left and right walls, the main and auxiliary heating circuit (9) of the rear wall, and the auxiliary heating circuit (10) of the bottom to operate at a power utilization rate of 75% to 85%. Step 5: When the main control temperature reaches the set heating threshold, switch to the constant temperature firing stage, that is, adjust the overall power utilization rate to 32%~42%; Step 6: Complete the firing control through graded abnormality protection control.

2. The precise temperature control method for a high-temperature argon atmosphere heating furnace according to claim 1, characterized in that: The basic parameters of the heating furnace (7) include at least one of the following: set heating temperature, low temperature threshold, over-temperature threshold, and over-temperature recovery threshold; the control parameters include at least one of the following: set heating rate, heating time, and initial argon flow rate.

3. The precise temperature control method for a high-temperature argon atmosphere heating furnace according to claim 1, characterized in that: During the heating phase, the monitoring temperature data is acquired in real time and compared with the main control temperature; if the monitoring temperature deviates from the main control temperature by 4℃~5℃, the power of the bottom auxiliary heating circuit (10) is increased or decreased by 8%~12%; during the heating phase, the argon flow rate is 15m³ / h~25m³ / h.

4. The precise temperature control method for a high-temperature argon atmosphere heating furnace according to claim 2, characterized in that, The isothermal firing stage includes the following operations: If the main control temperature is lower than the low temperature threshold, increase the power of the rear wall main and auxiliary heating circuit (9) by 8% to 12%, and simultaneously fine-tune the power of the left and right wall main heating circuits (8) by 5% to 8%. If the main control temperature is higher than the over-temperature threshold, reduce the power of the rear wall main and auxiliary heating circuit (9) by 8% to 12%, and then reduce the power of the left and right wall main heating circuits (8) by 5% to 8%. If the monitored temperature deviates from the temperature data value in the rear wall main and auxiliary heating circuit (9) by ≥2.5℃, the power of the bottom auxiliary heating circuit (10) is finely adjusted, and the adjustment range is 50% to 100% of the current power of the bottom auxiliary heating circuit (10).

5. The precise temperature control method for a high-temperature argon atmosphere heating furnace according to claim 2, characterized in that, The power distribution ratio of the left and right wall main heating circuits (8), the rear wall main and auxiliary heating circuits (9) and the bottom auxiliary heating circuit (10) is as follows: the left and right wall main heating circuits (8) account for 55.6% to 76.9% of the total power, the rear wall main and auxiliary heating circuits (9) account for 0% to 27.8%, and the bottom auxiliary heating circuits (10) account for 16.7% to 23.1%.

6. The precise temperature control method for a high-temperature argon atmosphere heating furnace according to claim 1, characterized in that: In step three, the power utilization rate during the heating stage is dynamically adjusted according to the actual heating rate. If the actual heating rate is less than the set heating rate, the power utilization rate is increased to 80% to 85%; if the actual heating rate is greater than the set heating rate, the power utilization rate is decreased to 75% to 80%.

7. The precise temperature control method for a high-temperature argon atmosphere heating furnace according to claim 1, characterized in that: Step two also includes establishing an argon circulation system and an argon flow control system; the argon circulation system and the argon flow control system dynamically adjust the argon circulation and argon flow based on the current power utilization rate, the temperature data of the temperature control and temperature measurement unit (21) and the temperature data of the monitoring and temperature measurement unit (22); During the constant temperature firing stage, when the deviation between the main control temperature and the monitoring temperature is ≥2℃, the speed of the high temperature circulating fan is increased by 10% to 20%.

8. The precise temperature control method for a high-temperature argon atmosphere heating furnace according to claim 7, characterized in that, The hierarchical anomaly protection control includes: When either the temperature measured by the temperature control unit (21) or the temperature monitoring unit (22) exceeds the over-temperature threshold, all heating circuits are triggered to stop heating and an alarm is triggered. If the temperature control and measurement unit (21) has no temperature feedback or the data is abnormal, the monitoring temperature data obtained by the monitoring and measurement unit (22) shall be used as the main control temperature; and the total heating power shall be limited to no more than 70% of the rated power. If the monitoring temperature measurement unit (22) fails, it will not affect the main control temperature, but will only trigger the bottom auxiliary heating circuit (10) to stop heating.

9. A precise temperature control system for a high-temperature argon atmosphere heating furnace (7), characterized in that, include: Main control module (1); temperature measurement module (2), heating control module (3), fan control module (4), gas path control module (5), abnormal protection module (6) electrically connected to the main control module (1); and left and right wall main heating circuits (8), rear wall main and auxiliary heating circuits (9) and bottom auxiliary heating circuits (10) distributed in the heating furnace (7); Temperature measurement modules (2) are distributed inside the heating furnace (7) to obtain the temperature inside the heating furnace (7) in real time; The heating control module (3) adjusts the power of the left and right wall main heating circuits (8), the rear wall main and auxiliary heating circuits (9) and the bottom auxiliary heating circuits (10) through solid-state relays (11) to dynamically adjust the power utilization and power distribution. The gas path control module (5) is used to adjust the flow rate of argon gas entering the heating furnace (7); the abnormal protection module (6) is used for abnormal protection of the heating furnace (7).

10. The precise temperature control system for a high-temperature argon atmosphere heating furnace (7) according to claim 9, characterized in that, The temperature measurement module (2) includes a temperature control and measurement unit (21) located on the upper part of the rear wall of the heating furnace (7) and a monitoring and measurement unit (22) located on the lower part of the rear wall of the heating furnace (7). Both the temperature control and temperature measurement unit (21) and the monitoring and temperature measurement unit (22) adopt K-type thermocouples.

11. The precise temperature control system for a high-temperature argon atmosphere heating furnace (7) according to claim 9, characterized in that, The anomaly protection module (6) includes: An audible and visual alarm (61) is electrically connected to the main control module (1); The power-off relay (62) receives the control signal from the main control module (1) and is connected in series with the main heating circuit (8) of the left and right walls, the main and auxiliary heating circuit (9) of the rear wall and the auxiliary heating circuit (10) of the bottom. The backup temperature control unit (63) is electrically connected to the monitoring and measuring unit (22); it is automatically started when the temperature control and measuring unit (21) fails, and the temperature obtained by the monitoring and measuring unit (22) is used as the main control temperature reference.

12. The precise temperature control system for a high-temperature argon atmosphere heating furnace according to claim 9, characterized in that, The gas path control module (5) includes: Flow control unit; A pressure sensor and a zirconium oxide oxygen content detector are installed in the argon gas communication circuit. And an electrically controlled butterfly valve installed on the argon gas connection line for controlling the argon gas connection line; The flow control unit, pressure sensor, zirconium oxide oxygen content detector, and electric control butterfly valve are all connected to the main control module (1) via signal.

Images