Research on the Application of AI Intelligent Temperature Control Instruments in Multi purpose Electric Furnaces

Wei Wanjun

(Xiamen Yudian Automation Technology Co., Ltd. Beijing Branch, Beijing 100000)

Abstract: Through the study of the use of new artificial intelligence temperature control instruments in multi-purpose resistance furnaces, the basic control principles and factors affecting temperature uniformity of multi-purpose resistance furnaces have been clarified. Based on the adjustment of control parameters of intelligent temperature control instruments during the process and the verification of furnace temperature uniformity measurement, the feasibility of applying and promoting AI intelligent temperature control instruments in multi-purpose resistance furnace equipment has been determined. This has laid the foundation for the intelligent upgrade of multi-purpose resistance furnaces, providing strong guarantees for precise temperature control and furnace temperature uniformity adjustment of multi-purpose resistance furnaces.

Keywords: New AI intelligent temperature control instrument, resistance furnace, furnace temperature accuracy, furnace temperature uniformity, intelligent control

Classification number: TH811. Literature identifier code: A Article number:

Application of AI intelligent temperature control instrument in multipurpose electric furnace

Wei wan jun

（Xiamen Yudian Automation Technology Co., Ltd. Beijing Branch，Beijing100000, China)

Abstract:Through the research on the application process of the new artificial intelligence temperature control instrument in the multi-purpose resistance furnace, the basic control principle and the influencing factors of temperature uniformity of the multi-purpose resistance furnace are clarified. Combined with the adjustment of control parameters of intelligent temperature control instrument in the process and the verification of furnace temperature uniformity measurement, the feasibility of application and popularization of AI intelligent temperature control instrument in multi-purpose resistance furnace equipment is determined. It lays a foundation for the intelligent upgrading of multi-purpose resistance furnace and provides a strong guarantee for the accurate temperature control and furnace temperature uniformity adjustment of multi-purpose resistance furnace.

Key words: New AI intelligent temperature control instrumentResistance furnaceFurnace temperature accuracyFurnace temperature uniformityIntelligent control

Introduction

With the development of industrial computers, it has driven innovation in the instrumentation industry. In recent years, temperature controllers have achieved vigorous development and are widely used in various fields. In the field of professional temperature control, intelligent temperature control instruments have brought a qualitative leap to temperature control. The application of artificial intelligence instruments in the field of temperature control has strong advantages, effectively solving problems that traditional instruments cannot solve. And the new intelligent temperature control instrument brings a qualitative change to various large-scale heating equipment. Not only does it simplify the control process, but it also improves the reliability of the instrument, enabling more accurate control of temperature signals, enhancing temperature feedback efficiency, and ultimately improving temperature control accuracy. In addition, the application of AI intelligent temperature control instruments provides intelligent "brains" for various large-scale heating equipment. Make intelligent operation of devices possible. The application and promotion of multi-purpose resistance furnaces have epoch-making significance for industry development, enabling intelligent transformation of multi-purpose resistance furnaces and deepening the concept of Industry 4.0 into the heating equipment industry.

1. Characteristics of the new AI intelligent temperature control instrument

The new AI intelligent temperature control instrument adopts modular design, with independent control chips for each module, humanized button layout, simple and easy adjustment, and conforms to conventional thinking regulation. The specific technical features are as follows:

(1) The new AI intelligent temperature control instrument can freely select thermocouples, thermistors, voltage, and current inputs, and can expand inputs and customize non-linear correction tables, with a measurement accuracy of 0.1 level.

(2) The new AI intelligent temperature control instrument adopts advanced AI artificial intelligence PID regulation algorithm, without overshoot, with self-tuning (AT) function and a new fine control mode.

(3) The instrument adopts advanced modular structure, provides rich output specifications, can widely meet the needs of various application scenarios, and is easy to maintain.

(4) The design concept of instruments emphasizes energy conservation and environmental protection, using high-quality components to achieve low power consumption and low temperature drift, effectively saving customers' energy. The sampling rate is 12.5 times per second, with a minimum control period of 0.24 seconds, which can adapt to the control accuracy of rapidly changing objects.

(5) The table adopts a user-friendly design operation method, which is easy to learn and use. Allow self editing operation permissions and interfaces, and can set passwords to create "customized" instruments.

(6) The instrument can be powered by a globally recognized 100-240VAC input range switch power supply or 24VDC power supply, and has multiple panel and external dimensions to choose from.

(7) The anti-interference performance of AI intelligent temperature control instruments meets the requirements of electromagnetic compatibility (EMC) under harsh industrial conditions.

(8) The AI intelligent temperature control instrument is a multi-purpose temperature control instrument that is adaptable to multiple environments and can be used on various heating devices. AI intelligent temperature control instruments should correctly set their input and output specifications and functional requirements before use. Only instruments with configured parameters can be put into use.

Research on Temperature Control of Multi purpose Resistance Furnace

2.1 Specification parameters of multi-purpose resistance furnace

The multi-purpose resistance furnace is designed and produced by a domestic manufacturer. The electric furnace has a large size and excellent sealing performance. The exterior of the furnace is made of medium and low carbon steel panels, and the interior is insulated with refractory materials and industrial asbestos. The furnace bottom plate is composed of refractory bricks and high-grade refractory metals. Design 12 sets of heating elements inside the furnace. The heating furnace is powered and controlled by four high-performance thyristor electric furnace temperature control cabinets, with detailed design parameters as follows:

table1. Technical parameters of multi-purpose resistance furnace

This multi-purpose resistance heating furnace was put into use in 2017, mainly used for annealing and tempering large alloy forgings. After years of high load use, the overall operation is normal, but the production product qualification rate has decreased. Users have raised questions about the performance of multi-purpose resistance furnaces and have requested modifications to their control performance.

Experimental Study on the Application of AI Intelligent Temperature Control Instrument in Multi purpose Resistance Furnace

According to on-site research, the temperature control instrument currently used in the multi-purpose resistance heating furnace is a conventional manual control instrument. There are four heating zones in the furnace, and the control cabinet is used to control the start and stop of the equipment outside the furnace. The temperature regulation during the operation of the heating furnace is achieved by manually inputting and controlling the temperature by the user. The instrument operates normally in the on-site usage environment. Through inspection of the internal control system of the heating furnace, the thyristor and electrical system inside the control box are normal, and the heating furnace thermocouple and compensation wire are normal.

The experiment first conducted multi-point temperature measurement on the heating furnace to explore the uniformity of furnace temperature. The temperature measurement points were arranged according to the national standard, and the temperature measurement plan was to measure the temperature in an empty furnace with 10 temperature measurement points set according to the national standard (as shown in the figure below). The temperature setting is as follows: 400 ℃× 3h → 620 ℃× 7h → power off for cooling (close the furnace door), and start air cooling when the furnace cools down to 300 ℃. The schematic diagram of temperature measurement points is as follows:

image1Arrangement of furnace temperature measurement points

After nearly 16 hours of temperature operation, temperature data of individual points inside the heating furnace were collected. Through processing, the temperature measurement curve shown in Figure 2 was generated. From the temperature measurement curve, it can be seen that the overall consistency of furnace temperature operation is good. However, in the initial stage of insulation, there will be uneven temperature at various points. The furnace temperature tends to become uniform with the extension of temperature measurement time. By recording the temperature at individual time points during the insulation period, it was found that the maximum temperature difference at each point reached about 27 ° C.

table2 Multi purpose Resistance Furnace Insulation Stage Temperature Collection Individual Time Data

image2Temperature variation curve of furnace temperature measurement point

Based on the above experimental results, the four control cabinet instruments were replaced with new AI intelligent temperature control instruments. The front panel control diagram and back wiring diagram of the instruments are as follows:

image3 AIFront and back schematic diagram of intelligent temperature control instrument

After replacing the AI intelligent temperature control meter in the multi-purpose resistance furnace, its process parameter design can be loaded at once without the need for manual temperature adjustment during the process. The parameters of the AI intelligent temperature control instrument are as follows:

table3 AI intelligent temperature control instrument technical parameters

The example of process temperature control is as follows:

The process curve in Figure 4 can be set according to the following steps:

The first paragraph SP 1=100.0 t 1=30.0; Starting from 100 ℃, linearly heat up to SP 2, with a heating time of 30 minutes and a heating slope of 10 ℃/min.

The second paragraph SP 2=400.0 t 2=60.0In400℃ insulation operation, with a duration of60Divide.

The third paragraph SP 3=400.0 t 3=120.0; Cool down to SP 4, with a cooling time of 120 minutes and a cooling slope of 2 ℃/min.

The fourth paragraph SP 4=160.0 t 4=0.0; After cooling down to 160 ℃, it enters a pause state and needs to run to continue running the next section.

The fifth paragraph SP 5=160.0 t 5=-1.0; Jump to the next step1Segment execution, starting from the beginning of the loop.

After replacing the AI intelligent temperature control instrument, the furnace temperature was measured again using the same temperature measurement process as before. The results show10The maximum temperature difference at each temperature measurement point shall not exceed10℃, as shown in the table below3The overall operating curve is shown in the following figure4：

Table 4 Individual time data collected during the insulation stage of the multi-purpose resistance furnace after replacing the intelligent instrument

image4Multi purpose resistance furnace adoptsAITemperature measurement curve after intelligent temperature control instrument

By applying AI intelligent temperature control instruments, the temperature uniformity of multi-purpose heating furnaces has been significantly improved. Temperature control is more precise, making it more convenient and reassuring for users to use. After nearly half a year of use, we conducted follow-up visits on the customer's performance and received feedback that the instrument was running well, effectively improving the qualification rate of heat-treated workpieces. The effect has been recognized and acknowledged by the customer.

3 Conclusion

1. The new AI intelligent temperature control instrument can be widely applied in multi-purpose resistance heating furnaces.

2. Through temperature measurement experiments, it has been found that the uneven temperature control of multi-purpose resistance furnaces is closely related to the need for instruments. AI intelligent temperature control instruments can achieve intelligent process setting and operation, greatly improving the temperature control accuracy and furnace temperature uniformity of multi-purpose resistance furnaces.

3. The AI intelligent temperature control instrument is installed and debugged through wiring, with a simple process, convenient parameter adjustment, and comprehensive functions, which can meet the control needs of industrial resistance furnaces.

4. References

5. [1] JJF 1376-2012 Calibration Specification for Box type Resistance Furnace [S].

6. [2] Song Huixin Yudian: Innovate the temperature control instrument market [J]. Automation Expo. Issue 1, 2015.

   [3] He Ying Optimization analysis of temperature uniformity in heating furnace [J]. Economic and Technological Cooperation Information, Issue 25, 2021