Rotary valve electric heating device and control method

Abstract

The invention relates to a rotary valve electric heating device and a control method. The control method of the rotary valve electric heating device comprises the steps that a first temperature signal of an electric heating plate and a second temperature signal of a rotary valve are obtained; filtering the first temperature signal and the second temperature signal to obtain a first filtering temperature and a second filtering temperature, and calculating a corresponding temperature difference value according to the first filtering temperature and the second filtering temperature; judging that the second filtering temperature is lower than a lower limit threshold of a preset target temperature interval, and judging that the second filtering temperature is higher than an upper limit threshold of the preset target temperature interval; judging whether the temperature difference value exceeds a temperature difference threshold, and judging whether the first filtering temperature exceeds a safety upper limit temperature; and switching on the power supply of the electric heating plate and switching off the power supply of the electric heating plate. The precision of temperature regulation and control is guaranteed, the temperature of the rotary valve shell is close to the process requirement range, and the stability and safety of the operation process are improved.

Description

Technical Field

[0001] This invention relates to the technical field of rotary valve heating, and in particular to an electric heating device and control method for a rotary valve. Background Technology

[0002] Currently, rotary valves are key equipment in pneumatic conveying systems, widely used in the powder conveying process of large-scale polyolefin plants. In the polymerization and conveying processes of polypropylene and polyethylene powders, the materials are typically in a high-temperature environment of approximately 100°C, accompanied by a large amount of olefin gas. To prevent olefin gas condensation on the valve body surface and maintain the precision of the gap between the rotor and the housing, rotary valves usually require an electric heating system. However, existing electric heating methods generally suffer from insufficient temperature control performance. Firstly, local overheating and uneven temperature distribution are prone to occur during the heating process, leading to excessively high local temperatures in the valve body or rotor, causing material melting, agglomeration, or even jamming, resulting in equipment malfunction. Secondly, when the electric heating rod is in an overheated state for a long time, it may burn out, affecting the stable operation of the system. In addition, the gap control between the rotary valve rotor and the housing is also highly dependent on temperature conditions. When the gap is too large, material backflow is likely to occur, affecting conveying efficiency; when the gap is too small, under uneven heating conditions, the rotor and housing may collide due to differences in thermal expansion and contraction, causing scratches on the inner wall or rotor surface, which can seriously affect the valve body's lifespan. Therefore, how to achieve more precise and stable temperature control in rotary valve electric heating systems to avoid safety hazards and efficiency losses caused by local overheating and temperature fluctuations remains a problem that needs to be solved by existing technologies. Summary of the Invention

[0003] To address the problems of uneven temperature distribution, localized overheating, and thermal deformation of gaps during the electric heating process of existing rotary valves, which lead to decreased conveying efficiency and equipment reliability, this application provides an electric heating device and control method for rotary valves.

[0004] A control method for a rotary valve electric heating device is provided, applied to a rotary valve electric heating device comprising a rotary valve and an electric heating plate, wherein the electric heating plate is connected to the rotary valve for heating the rotary valve, and the control method includes: Acquire a first temperature signal by means of a temperature probe arranged on an electric heating plate, and a second temperature signal by means of a temperature sensor arranged in a blind hole in the rotary valve housing; The first temperature signal and the second temperature signal are filtered respectively to obtain the first filtered temperature and the second filtered temperature, and the corresponding temperature difference value is calculated based on the first filtered temperature and the second filtered temperature. When the second filtered temperature is lower than the lower threshold of the preset target temperature range, a first control command is generated; when the second filtered temperature is higher than the upper threshold of the preset target temperature range, a second control command is generated. Determine whether the temperature difference value exceeds the temperature difference threshold. If it exceeds the temperature difference threshold, generate a third control command. If the temperature difference threshold is not exceeded, then it is determined whether the first filtered temperature exceeds the safe upper limit temperature. If it exceeds the safe upper limit temperature, then a fourth control command is generated. When the first control command is detected and the second, third and fourth control commands are not detected, the operation of turning on the power supply of the electric heating plate is executed; when any one of the second, third or fourth control commands is detected, the operation of turning off the power supply of the electric heating plate is executed.

[0005] By adopting the above technical solution, filtering the real-time temperature signal, and generating corresponding control commands when different filtered temperatures exceed the upper and lower limits of the set target temperature range, automatic start-stop control of the electric heating system is achieved. This effectively avoids overheating or overcooling caused by temperature fluctuations, ensuring the rotary valve operates in a stable temperature environment. It guarantees the accuracy of temperature control, keeping the rotary valve shell temperature close to the process requirements, and improves the stability and safety of the operation, avoiding frequent fluctuations and extreme failures. This results in more precise and stable control of the rotary valve's electric heating process.

[0006] Preferably, the step of generating a first control command when the second filtered temperature is lower than the lower threshold of the preset target temperature range, and generating a second control command when the second filtered temperature is higher than the upper threshold of the preset target temperature range, includes: A safe connection threshold is set below the lower threshold, and a safe disconnection threshold is set above the upper threshold. When the second filtered temperature is within the first numerical range between the safe turn-on threshold and the lower limit threshold, the first delay determination stage is entered. If the second filtered temperature remains within the first numerical range during the determination period of the first delay determination stage, a first control command is generated. When the second filter temperature is lower than the safe turn-on threshold, a first control command is immediately generated; When the second filtered temperature is within the second numerical range between the safety disconnection threshold and the upper limit threshold, the second delay determination stage is entered. If the second filtered temperature remains within the second numerical range during the determination period of the second delay determination stage, a second control command is generated. When the second filter temperature is higher than the safety disconnection threshold, a second control command is immediately generated.

[0007] By adopting the above technical solution, setting a hysteresis range based on the target temperature value, and introducing on and off thresholds, the frequent triggering of control commands when the temperature signal fluctuates repeatedly near the upper and lower limits is avoided, thereby improving the stability and reliability of system control and reducing the number of invalid switching of electric heaters.

[0008] Preferably, the step of generating the determination period in the first delay determination stage includes: Calculate the first deviation between the second filtered temperature and the lower limit threshold, and determine the first initial determination period of the first delay determination stage based on the first deviation and the preset deviation mapping relationship. Based on the comparison relationship between the temperature difference value and the temperature difference threshold, the first initial determination period is corrected to generate a corresponding first corrected determination period; The first correction determination period is modified a second time by using the first historical period recorded in the previous control period to generate the determination period of the first delay determination stage. The steps for generating the determination period in the second delay determination stage include: Calculate the second deviation between the second filtered temperature and the lower limit threshold, and determine the second initial determination period of the second delay determination stage based on the second deviation and the preset deviation mapping relationship. Based on the comparison relationship between the temperature difference value and the temperature difference threshold, the second initial determination period is corrected to generate a corresponding second corrected determination period. The second correction determination period is modified a second time by using the second historical period recorded in the previous control period to generate the determination period for the second delay determination stage.

[0009] By adopting the above technical solution, introducing a first delay determination stage and a second delay determination stage, and calculating and correcting the determination cycle based on the deviation, the influence of instantaneous temperature fluctuations on the generation of control commands is effectively filtered out, making the control logic smoother and more stable, and significantly reducing malfunctions caused by short-term temperature difference interference.

[0010] Preferably, the step of performing a second correction on the first correction determination period using the first historical period recorded in the previous control period to generate the determination period for the first delay determination stage includes: Determine the first cycle ratio parameter between the first historical cycle and the first correction determination cycle; When the first cycle ratio parameter is less than 1, the first correction determination period is extended based on the first cycle ratio parameter to generate the determination period of the first delay determination stage. When the first cycle ratio parameter is greater than 1, the first correction determination cycle is shortened based on the first cycle ratio parameter to generate the determination cycle of the first delay determination stage. The step of performing a second correction on the second correction determination period using the second historical period recorded in the previous control period to generate the determination period for the second delay determination stage includes: Determine the second cycle ratio parameter between the second historical cycle and the second correction determination cycle; When the second cycle ratio parameter is less than 1, the second correction determination period is extended based on the second cycle ratio parameter to generate the determination period of the second delay determination stage. When the second period ratio parameter is greater than 1, the second correction determination period is shortened based on the second period ratio parameter to generate the determination period of the second delay determination stage.

[0011] By adopting the above technical solution, the determination period is modified twice by combining historical cycles, and the determination period is dynamically extended or shortened according to the cycle ratio parameter. This forms a self-learning determination mechanism based on historical operating data, which enables the delay control to adapt to the temperature fluctuation characteristics under different operating conditions and further improves the control's adaptive capability.

[0012] Preferably, in the step of determining whether the temperature difference value exceeds a temperature difference threshold, and generating a third control command if it exceeds the temperature difference threshold, the electric heating plate is provided with electric heating rods arranged in sequence, wherein each electric heating rod is defined as an independent electric heating area, and the step further includes: Determine whether the temperature difference value exceeds a preset feedback value range, wherein the upper limit of the value range in the feedback value range is a temperature difference threshold. If so, then generate a third control command; If not and it is within the preset feedback value range, then the heating power in the independent electric heating area is pre-adjusted in sequence, and the temperature difference value after adjusting the heating power is recalculated. The previously obtained temperature difference value is compared with the temperature difference value after adjusting the heating power to generate a corresponding comparison result. Based on the comparison result, the electric heating independent area with a significant reduction in temperature difference value is determined as the target area. Adjust the heating power parameters of the target area until the temperature difference value drops below the lower limit of the feedback value range.

[0013] By adopting the above technical solution, and by calculating the temperature difference between zones within the judgment period and determining whether it falls within the feedback value range, dynamic adjustment of the independent power of each heating zone is achieved. This enables precise compensation for the local temperature difference of the rotary valve, ensuring a more uniform overall heat distribution and effectively solving the problems of local overheating or insufficient heating.

[0014] Preferably, the step of generating the safe upper limit temperature includes: Determine a temperature difference reference value, wherein the reference temperature difference value is less than the temperature difference threshold, and calculate the difference offset between the temperature difference reference value and the temperature difference value; The difference offset is multiplied by a preset convergence coefficient to correct the preset baseline upper limit temperature and generate the corresponding first initial upper limit temperature. The slope of the temperature difference value within a preset time window is obtained, and the slope is multiplied by a preset slope coefficient to generate a corresponding slope correction amount. The first initial upper limit temperature is corrected based on the slope correction amount to generate a corresponding second initial upper limit temperature. Determine the upper limit of the material temperature resistance of the electric heating plate, compare the upper limit of the material temperature resistance with the preset minimum allowable upper limit, generate a corresponding comparison result, and clamp the second initial upper limit temperature according to the comparison result to generate a corresponding safe upper limit temperature.

[0015] By adopting the above technical solution, and by introducing dynamic correction parameters based on the upper limit of safety temperature, and adjusting them in real time in conjunction with the actual temperature difference, the upper limit of safety can change with the thermal state of the system. This effectively avoids over-protection or under-protection that may be caused by a fixed threshold, and improves the balance between safety and flexibility of the system.

[0016] A rotary valve electric heating device, comprising: Rotary valve; There are two electric heating plates, and the heating end faces of the two electric heating plates are respectively embedded on opposite sides of the rotary valve. The heating end faces are arc-shaped and keep the same axis as the rotor of the rotary valve. A temperature control system is installed on one side of the electric heating plate and electrically connected to a temperature probe disposed on the electric heating plate to acquire a first temperature signal of the electric heating plate. The insulation shell is fitted and mates with the mounting body, which is a structural component after the rotary valve and the electric heating plate are fitted and installed together. A temperature sensor is provided, with its detection end passing through the insulation shell and the valve body of the rotary valve in sequence, to connect with a pre-reserved temperature measurement blind hole on the inner side of the rotary valve. The temperature sensor is electrically connected to the temperature control system.

[0017] By adopting the above technical solution and setting up a first filter sensor and a second filter sensor, temperature signals from different locations can be collected respectively. In conjunction with the coordinated work of the electric heating plate and the central controller, accurate real-time monitoring and control are achieved, ensuring that the heating process is more intelligent and controllable.

[0018] Preferably, the electric heating plate includes: plate body; Multiple electric heating rods are provided and arranged sequentially at intervals on the inner side of the plate. A reserved temperature monitoring hole is provided between each two adjacent electric heating rods, and each reserved temperature monitoring hole is electrically connected to the temperature control system.

[0019] By adopting the above technical solution, the locking structure between the electric heating plate and the rotary valve body enables the electric heating plate to be quickly disassembled and stably fixed, which facilitates maintenance and replacement, and ensures efficient heat transfer to the rotary valve, thereby improving the adaptability of the structure and heating efficiency.

[0020] Preferably, the plate body is provided with a plurality of spaced-apart inserts, the side of the inserts near the rotary valve is combined to form the heating end face, and the rotary valve is provided with a groove that fits into the inserts.

[0021] By adopting the above technical solution, by embedding electric heating rods in the electric heating plate and combining the shell and insulation layer, not only is the local heating capacity improved, but the loss of external heat is also reduced, forming an efficient and stable thermal management structure, thereby reducing energy consumption and improving heating uniformity.

[0022] Preferably, the inserts are arranged in a matrix, and each row of inserts on the side is provided with a snap-fit ​​groove, and the groove is provided with a protrusion that engages with the snap-fit ​​groove.

[0023] By adopting the above technical solution, and by setting grooves and temperature monitoring holes on the contact surface between the electric heating plate and the rotary valve, it is not only convenient to embed electric heating rods and sensors, but also to realize local heat concentration conduction and real-time temperature monitoring, thereby enhancing the controllability of zoned heating and the accuracy of temperature management.

[0024] In summary, this application includes at least one of the following beneficial technical effects: This application employs temperature acquisition units on both the electric heating plate and the rotary valve housing to acquire a first temperature signal and a second temperature signal, respectively. These signals are then filtered, eliminating the bias and transient noise interference inherent in single-point temperature measurement and resulting in more stable and reliable temperature data. By calculating the temperature difference between the filtered electric heating plate temperature and the housing temperature, the deviation between the heating response and the actual heating is reflected. This allows for timely triggering of protection in case of abnormal temperature differences, preventing temperature control failure due to localized overheating or heat transfer lag. Based primarily on the second filtered temperature of the rotary valve housing, a first control command to activate heating is generated when the temperature falls below the lower threshold of the target range, and a second control command to deactivate heating is generated when the temperature exceeds the upper threshold. This ensures the housing temperature is consistently maintained within the preset target range, guaranteeing a suitable temperature environment for materials during transport and preventing condensation and adhesion. Simultaneously, the temperature difference threshold judgment and the safe upper limit judgment of the electric heating plate temperature serve as multi-level protection mechanisms. When the temperature difference is too large or the heating plate temperature is too high, a third or fourth control command is immediately generated, prioritizing the deactivation operation to ensure no localized overheating or runaway occurs. This not only ensures the accuracy of temperature control, keeping the rotary valve housing temperature close to the process requirements, but also improves the stability and safety of the operation process, avoiding frequent fluctuations and extreme failures, thereby achieving more precise and stable control of the rotary valve's electric heating process. Attached Figure Description

[0025] Figure 1 This is a flowchart of a control method for a rotary valve electric heating device according to an embodiment of this application.

[0026] Figure 2 This is a schematic diagram of the specific structure of a rotary valve electric heating device according to one embodiment of this application; Figure 3 This is an exploded disassembly diagram of a rotary valve electric heating device according to one embodiment of this application; Figure 4 This is a schematic diagram of the specific connection structure of the temperature sensor in a rotary valve electric heating device according to one embodiment of this application; Figure 5 This is a schematic diagram of the specific structure of the electric heating rod and the reserved temperature monitoring hole in an embodiment of the rotary valve electric heating device of this application. Figure 1 ; Figure 6 This is a schematic diagram of the specific structure of the electric heating rod and the reserved temperature monitoring hole in an embodiment of the rotary valve electric heating device of this application. Figure 2 .

[0027] Explanation of reference numerals in the attached figures: 1. Rotary valve; 11. Temperature measurement blind hole; 12. Groove; 13. Protrusion; 2. Electric heating plate; 21. Plate body; 211. Insert; 212. Snap-fit ​​groove; 22. Electric heating rod; 23. Reserved temperature monitoring hole; 3. Temperature control system; 4. Insulation shell; 5. Temperature sensor; 6. Explosion-proof junction box; 7. Main junction box. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the accompanying drawings.

[0029] In one embodiment, such as Figure 1 As shown, this application discloses a control method for a rotary valve electric heating device, applied to a rotary valve electric heating device. The rotary valve electric heating device includes a rotary valve and an electric heating plate, the electric heating plate being connected to the rotary valve for heating the rotary valve. The control method includes: S10. Acquire a first temperature signal obtained by a temperature probe arranged on an electric heating plate, and a second temperature signal obtained by a temperature sensor arranged in a blind hole in the rotary valve housing. S20. The first temperature signal and the second temperature signal are filtered respectively to obtain a first filtered temperature and a second filtered temperature, and the corresponding temperature difference value is calculated based on the first filtered temperature and the second filtered temperature. The temperature signals are processed in real time based on a preset filtering algorithm, wherein the filtering algorithm eliminates instantaneous temperature fluctuations caused by disturbances in the surrounding environment of the rotary valve by weighted averaging the temperature sample values ​​within a fixed time window. The processed first temperature signal is converted into a first filtered temperature, and the processed second temperature signal is converted into a second filtered temperature. The first filtered temperature is used to determine the dynamic change trend of the overall temperature of the rotary valve, and the second filtered temperature is used to compare with a preset target temperature range and generate corresponding control commands. By filtering them separately, it is possible to ensure that the first temperature signal stably reflects the overall heating state of the rotary valve over a large range, and to ensure the real-time accuracy of the second temperature signal in local heating control, thereby improving the temperature control accuracy and stability of the electric heating system during operation.

[0030] S30. When the second filter temperature is lower than the lower threshold of the preset target temperature range, a first control command is generated; when the second filter temperature is higher than the upper threshold of the preset target temperature range, a second control command is generated. S40. Determine if the temperature difference exceeds the temperature difference threshold. If it does, generate a third control command. When the temperature difference is significantly greater than the threshold, it usually means that there is a significant deviation between the heating efficiency of the electric heating plate and the actual heating state of the rotary valve. This deviation may cause some areas of the rotary valve to overheat while other areas remain at a low temperature, thus affecting the overall operational stability and sealing reliability of the rotary valve. By generating a third control command and promptly cutting off the power to the electric heating plate when the temperature difference exceeds the threshold, material performance degradation or structural damage caused by local overheating can be avoided. It also prevents the control system from becoming unbalanced due to lag in heat conduction, thereby achieving safe and balanced control of the rotary valve heating process.

[0031] S50. If the temperature difference threshold is not exceeded, determine whether the first filter temperature exceeds the safe upper limit temperature. If it does, generate a fourth control command. When the temperature difference value does not exceed the temperature difference threshold, the system considers the heat transfer between the electric heating plate and the rotary valve to be in an acceptable balance, meaning there is no significant deviation between the heating effect of the heating plate and the heating effect of the rotary valve body. In this case, the control logic no longer prioritizes the temperature difference but instead further judges the first filter temperature to ensure that the electric heating plate itself does not accumulate excessive heat due to heat transfer lag. Therefore, the system only enters the judgment step of the first filter temperature when the temperature difference value does not exceed the temperature difference threshold, thus enabling the control logic to achieve hierarchical decision-making based on the temperature difference reference value and avoiding redundant repeated judgments.

[0032] Specifically, even if the temperature of the rotary valve body remains within the target temperature range, if the first filter temperature of the electric heating plate continues to rise and exceeds the safe upper limit temperature, it may cause the internal components of the heating plate to fail due to overheating, or cause the risk of localized overheating on the surface of the rotary valve housing. By generating a fourth control command under this condition, an independent safety protection mechanism can be provided for the electric heating plate, avoiding the control blind spots that may occur when relying solely on temperature difference control, thereby further improving the overall safety and reliability of the rotary valve electric heating system.

[0033] S60. When the first control command is detected and the second, third and fourth control commands are not detected, the operation of turning on the power supply of the electric heating plate is executed; when any one of the second, third or fourth control commands is detected, the operation of turning off the power supply of the electric heating plate is executed.

[0034] Furthermore, the step of generating a first control command when the second filtered temperature is lower than the lower threshold of the preset target temperature range, and generating a second control command when the second filtered temperature is higher than the upper threshold of the preset target temperature range, includes: S301. A safe on threshold is set below the lower threshold and a safe off threshold is set above the upper threshold. The system sets safe on thresholds and safe off thresholds outside the upper and lower boundaries of the temperature range to form a control band with buffer characteristics.

[0035] S302. When the second filter temperature is in the first numerical range between the safe turn-on threshold and the lower limit threshold, the first delay determination stage is entered. If the second filter temperature continues to remain within the first numerical range during the determination period of the first delay determination stage, a first control command is generated. S303. When the second filter temperature is below the safe turn-on threshold, a first control command is immediately generated. When the second filter temperature gradually decreases and approaches the lower limit of the range, if it enters the temperature range between the safe turn-on threshold and the lower limit threshold, the system will not immediately start heating, but will enter the first delay judgment stage. In this stage, the system continuously monitors the change of the second filter temperature within a set judgment period. Only when it remains within the temperature range throughout the entire period will the first control command for heating be issued. This effectively avoids unnecessary frequent on / off switching caused by short-term temperature fluctuations near the boundary. If the second filter temperature continues to decrease and falls below the safe turn-on threshold, it indicates that the temperature is significantly low. At this time, the system will immediately output the first control command to quickly start heating, ensuring that the rotary valve can still operate stably in low-temperature environments.

[0036] S304. When the second filter temperature is in the second numerical range between the safety disconnection threshold and the upper limit threshold, the second delay determination stage is entered. If the second filter temperature continues to remain within the second numerical range during the determination period of the second delay determination stage, a second control command is generated. S305. When the second filter temperature exceeds the safety disconnection threshold, a second control command is immediately generated. Correspondingly, as the second filter temperature gradually rises and approaches the upper limit of the range, if it enters the temperature range between the upper limit threshold and the safety disconnection threshold, the system enters a second delayed judgment phase. Within one judgment cycle, it continuously monitors whether the temperature is stably maintained within this range. If the condition is met, a second control command to stop heating is generated. This strategy avoids frequent disconnections caused by short-term temperature spikes. If the second filter temperature continues to rise and exceeds the safety disconnection threshold, the system determines that the temperature has significantly exceeded the limit and immediately generates a second control command to cut off heating in a timely manner, thereby preventing damage to the rotary valve and heating plate due to overheating.

[0037] In summary, this layered decision-making logic allows the system to respond quickly when the temperature deviates significantly from the target range during heating start-up and shutdown control, and to improve the stability of the decision-making by using a delay mechanism when approaching the range boundary. This ensures operational safety while avoiding energy consumption and device impact caused by frequent switching.

[0038] Furthermore, the steps for generating the determination period in the first delay determination phase include: Calculate the first deviation between the second filtered temperature and the lower limit threshold, and determine the first initial determination period of the first delay determination stage based on the first deviation and the preset deviation mapping relationship. Based on the comparison relationship between the temperature difference value and the temperature difference threshold, the first initial judgment period is corrected to generate a corresponding first corrected judgment period. The first correction judgment period is modified a second time by using the first historical period recorded in the previous control period to generate the judgment period for the first delayed judgment stage. In this embodiment, the preset deviation mapping relationship is set to monotonically shorten the judgment period as the first deviation increases, thereby enabling faster heating when the temperature is lower. Subsequently, the current temperature difference value is obtained and compared with a temperature difference threshold: if the temperature difference value is larger than the temperature difference threshold, it indicates a risk of lag in heat transfer from the electric heating plate to the rotary valve; in this case, the first initial judgment period is extended to avoid excessively rapid energization. If the temperature difference value is smaller than the temperature difference threshold, it indicates good plate-valve temperature matching; in this case, the first initial judgment period is shortened to improve heating response, and the corrected result is used as the first corrected judgment period. Finally, the first historical period recorded in the previous control cycle is called to perform a second correction on the first corrected judgment period: when the first historical period is short (meaning frequent recent switching), the current period is appropriately extended to improve stability; when the first historical period is long (meaning the system remains in a certain state for a longer period), the current period is appropriately shortened to improve responsiveness. The result after the second correction is used as the judgment period for the first delay judgment stage, used to determine the persistence of the second filtered temperature within the first numerical range.

[0039] The steps for generating the determination period in the second delay determination phase include: Calculate the second deviation between the second filtered temperature and the upper limit threshold, and determine the second initial judgment period of the second delay judgment stage based on the second deviation and the preset deviation mapping relationship. Based on the comparison between the temperature difference value and the temperature difference threshold, the second initial judgment period is corrected to generate the corresponding second corrected judgment period; The second correction determination period is modified a second time by using the second historical period recorded in the previous control period to generate the determination period for the second delay determination stage.

[0040] In this embodiment, the determination cycle of the second delay determination stage is generated using the same chain-like process, but with a mirror configuration around the upper limit side: when the second filter temperature is between the upper limit threshold and the safety disconnection threshold, the second deviation between the second filter temperature and the upper limit threshold is first calculated, and the second initial determination cycle is obtained according to the preset deviation mapping relationship; this mapping relationship is set to monotonically shorten the determination cycle as the second deviation increases, so that the heating stop determination is entered faster when the temperature is closer to the safety disconnection threshold. Subsequently, the current temperature difference value is obtained and compared with the temperature difference threshold: if the temperature difference value is larger than the temperature difference threshold, it indicates that the plate temperature is significantly higher than the valve body temperature, and there is a local overheating trend, so the second initial determination cycle is shortened to accelerate the heating stop; if the temperature difference value is smaller than the temperature difference threshold, it indicates that the heat transfer is more balanced, so the second initial determination cycle is extended to avoid unnecessary disconnection, and the corrected result is used as the second corrected determination cycle. Finally, the second historical period recorded in the previous control cycle is used to perform a second correction on the second correction judgment period: when the second historical period is short, it is appropriately extended to suppress high-frequency switching; when the second historical period is long, it is appropriately shortened to improve the response speed to over-temperature trends. The result after the second correction is used as the judgment period for the second delay judgment stage to determine the persistence of the second filtered temperature within the second numerical range. Through the above continuous chain from the deviation to the initial judgment period, then to the correction based on the temperature difference value, and finally to the second correction based on the historical period, the delay judgment on both sides can respond quickly when the temperature deviates significantly, and suppress jitter near the boundary, taking into account both responsiveness and stability.

[0041] Furthermore, the step of performing a second correction on the first correction determination period based on the first historical period recorded in the previous control period to generate the determination period for the first delay determination stage includes: Determine the first cycle ratio parameter between the first historical cycle and the first correction determination cycle; When the first cycle ratio parameter is less than 1, the first correction determination period is extended based on the first cycle ratio parameter to generate the determination period of the first delayed determination stage. When the first cycle ratio parameter is greater than 1, the first correction judgment period is shortened based on the first cycle ratio parameter to generate the judgment period of the first delayed judgment stage. In this embodiment, during the first delay determination phase, the central controller first acquires the first historical cycle recorded in the previous control cycle and performs a ratio calculation with the first corrected determination cycle obtained from the deviation mapping relationship and temperature difference correction rule to determine the first cycle proportional parameter. The first cycle proportional parameter is used to measure the deviation of the "historical actual situation" from the "current planned determination cycle": when the first cycle proportional parameter is less than 1, it indicates that the state holding time in the previous control cycle is shorter than the first corrected determination cycle, and the system has a high switching frequency; to suppress this high-frequency switching, the central controller extends the first corrected determination cycle based on the first cycle proportional parameter, making the determination cycle of the new first delay determination phase longer, thereby improving the immunity to short-term fluctuations. Conversely, when the first cycle proportional parameter is greater than 1, it indicates that the state holding time in the previous control cycle is longer than the first corrected determination cycle, and the system response is conservative; to improve the response speed, the central controller shortens the first corrected determination cycle based on the first cycle proportional parameter, and the determination cycle of the obtained first delay determination phase is closer to the actual thermal inertia and operating condition changes. To avoid introducing new jitter due to excessively large correction scale, the embodiment can introduce a limiting strategy when extending or shortening the time, so that the determination period of the first delay determination stage is subject to the dual constraints of the minimum determination period and the maximum determination period, and a smoothing coefficient is used to achieve gradual convergence within the continuous control period.

[0042] The step of modifying the second correction determination period by using the second historical period recorded in the previous control period to generate the determination period for the second delay determination stage includes: Determine the second cycle ratio parameter between the second historical cycle and the second correction determination cycle; When the second cycle ratio parameter is less than 1, the second correction judgment period is extended based on the second cycle ratio parameter to generate the judgment period of the second delayed judgment stage. When the second cycle ratio parameter is greater than 1, the second correction determination cycle is shortened based on the second cycle ratio parameter to generate the determination cycle of the second delayed determination stage.

[0043] In this embodiment, during the second delay determination phase, the central controller processes the upper limit side determination cycle using the same procedure: first, it acquires the second historical cycle recorded in the previous control cycle and performs a ratio calculation with the second corrected determination cycle obtained from the deviation mapping relationship and temperature difference correction rule to determine the second cycle proportional parameter. When the second cycle proportional parameter is less than 1, it indicates that the state switch was triggered quickly after the last entry into the upper limit side determination, indicating a high-frequency switching trend on the upper limit side. To enhance stability, the central controller extends the second corrected determination cycle based on the second cycle proportional parameter, resulting in a longer determination cycle for the second delay determination phase, thereby avoiding unnecessary heating stoppages caused by short-term temperature spikes. When the second cycle proportional parameter is greater than 1, it indicates that the upper limit side historical holding time is relatively long, and the system response is slow when approaching the upper limit threshold. To accelerate the suppression of overheating trends, the central controller shortens the second corrected determination cycle based on the second cycle proportional parameter, resulting in a more timely determination cycle for the second delay determination phase. Similarly, in this embodiment, cycle limiting and smooth convergence rules are set during the extension or shortening operation to achieve a balance between stability and responsiveness in the determination cycle of the second delay determination phase.

[0044] Furthermore, in the step of determining whether the temperature difference exceeds a temperature difference threshold, and generating a third control command if it does, the electric heating plate is equipped with sequentially arranged electric heating rods, wherein each electric heating rod is defined as an independent electric heating area. The step also includes: S401. Determine whether the temperature difference value exceeds the preset feedback value range. The upper limit of the value range in the feedback value range is the temperature difference threshold. S402, If yes, then a third control command is generated. Inside the electric heating plate, a heating assembly is composed of multiple sequentially arranged electric heating rods. Each electric heating rod is defined as an independent electric heating area, thereby achieving regional heating control. During actual operation, the central controller first calculates the temperature difference value based on the first and second filtered temperatures and compares it with a preset feedback value range, where the upper limit of the feedback value range is set as the temperature difference threshold. If the temperature difference value directly exceeds the upper limit of the feedback value range, i.e., exceeds the temperature difference threshold, it indicates that the overall temperature distribution is severely uneven. At this time, a third control command is immediately generated to trigger rapid protection or power reduction actions to avoid structural stress risks or local overheating caused by excessive temperature differences.

[0045] S403. If not and within the preset feedback value range, then adjust the heating power of the independent electric heating area in sequence and recalculate the temperature difference value after adjusting the heating power. S404. Compare the previously acquired temperature difference value with the temperature difference value after adjusting the heating power to generate a corresponding comparison result. Based on the comparison result, determine the independently heated electric heating area with a significant reduction in temperature difference as the target area. When the temperature difference value does not exceed the temperature difference threshold but is still within the feedback value range, it indicates that although the current temperature difference distribution has not reached the limit state, it has entered the range requiring intervention. At this time, the system will not immediately take extreme control measures, but will conduct test intervention by sequentially pre-adjusting the heating power of each independently heated electric heating area. Specifically, the central controller changes the heating power parameter of each independently heated electric heating area one by one, and recalculates the new temperature difference value after each pre-adjustment, forming a comparison result of "temperature difference value before adjustment" and "temperature difference value after adjustment". By analyzing the comparison result, it is possible to identify which independently heated electric heating area has the most significant effect on reducing the temperature difference value after power adjustment, thereby determining that area as the target area.

[0046] S405. Adjust the heating power parameters of the target area until the temperature difference value drops below the lower limit of the feedback value range. Once the target area is identified, the central controller further adjusts its heating power parameters for that area to continuously reduce its contribution to temperature unevenness. During this process, the system continuously calculates and compares the temperature difference value until the monitoring results show that the temperature difference value has dropped below the lower limit of the feedback value range, indicating that the temperature distribution has returned to equilibrium. This not only enables precise zoned adjustment but also avoids the crude power reduction measures applied to the entire plate, improving heating efficiency and temperature field uniformity.

[0047] Furthermore, the steps for generating the safe upper limit temperature include: Determine a temperature difference reference value, where the reference temperature difference value is less than the temperature difference threshold, and calculate the difference offset between the temperature difference reference value and the temperature difference value. The system multiplies the difference offset by a preset convergence coefficient to correct the preset baseline upper limit temperature, generating the corresponding first initial upper limit temperature. First, the system sets a temperature difference reference value less than a temperature difference threshold and compares this reference value with the real-time temperature difference value to calculate the difference offset. This difference offset reflects the degree of deviation between the current temperature difference and the ideal reference temperature difference. Then, the system multiplies this difference offset by a preset convergence coefficient and applies the result to correct the preset baseline upper limit temperature, thus obtaining the first initial upper limit temperature. The principle behind this is: when the temperature difference value is close to the temperature difference reference value, the correction magnitude is small, and the upper limit temperature remains close to the baseline; while when the temperature difference value deviates significantly from the reference value, the correction magnitude increases, and the upper limit temperature is dynamically lowered to trigger protection earlier.

[0048] The system obtains the slope of the temperature difference within a preset time window, multiplies this slope by a preset slope coefficient to generate a corresponding slope correction. Based on this slope correction, the first initial upper limit temperature is adjusted to generate a corresponding second initial upper limit temperature. Next, the system further incorporates the slope of the temperature difference within the preset time window, calculates this slope, and multiplies it by a preset slope coefficient to generate another slope correction. The slope correction reflects the trend of the temperature difference change, i.e., whether the temperature difference is widening or gradually converging. If the slope is positive and large, it indicates that the temperature difference is rapidly increasing. In this case, the system uses the slope correction to further lower the first initial upper limit temperature to generate a second initial upper limit temperature, preventing temperature exceedances due to worsening temperature differences in the near future. If the slope is small or negative, it indicates that the temperature difference is stabilizing or decreasing. In this case, the slope correction is small or even close to zero, and the upper limit temperature remains relatively stable, avoiding overly conservative control.

[0049] The system determines the upper limit of the heating plate's material temperature resistance, compares this upper limit with a preset minimum allowable upper limit, generates a comparison result, and clamps the second initial upper limit temperature based on this result, thus generating a corresponding safe upper limit temperature. Finally, the system introduces a hardware safety boundary, namely the upper limit of the heating plate's material temperature resistance, combined with a preset minimum allowable upper limit as a safety redundancy baseline. By comparing the upper limit of the material temperature resistance with the minimum allowable upper limit, the system generates a comparison result and clamps the second initial upper limit temperature accordingly. The principle is to ensure that the final safe upper limit temperature does not exceed the material's physical tolerance limit, nor does it fall below the minimum allowable value, thus preventing excessive power reduction and forming a dynamically adjustable but always safe upper limit temperature.

[0050] In summary, by using the difference offset to ensure adaptability to real-time temperature differences, using the slope correction to reflect preventative control of future trends, and using material temperature resistance constraints to ensure an absolute safety boundary, a flexible and reliable safety upper limit temperature is generated.

[0051] like Figures 2-6 As shown, a rotary valve electric heating device includes: Rotary valve 1; There are two electric heating plates 2. The heating end faces of the two electric heating plates are respectively embedded on the opposite sides of the rotary valve. The heating end faces are arc-shaped and keep the same axis as the rotor of the rotary valve. Temperature control system 3 is installed on one side of electric heating plate 2 and electrically connected to temperature probe provided on electric heating plate 2 to acquire first temperature signal of electric heating plate 2; Insulation shell 4, which is fitted and fitted with the mounting body, which is a structural component after the rotary valve 1 and the electric heating plate 2 are fitted and installed together; Temperature sensor 5, the detection end of temperature sensor 5 passes through the insulation shell 4 and the valve body of rotary valve 1 in sequence, so as to connect with the temperature measurement blind hole 11 reserved in advance on the inner side of rotary valve 1. Temperature sensor 5 is electrically connected to temperature control system 3.

[0052] Furthermore, such as Figure 3 As shown, the electric heating plate 2 includes: Plate body 21; There are multiple electric heating rods 22, which are arranged in sequence at intervals on the inner side of the plate 21. Each interval between two adjacent electric heating rods 22 is provided with a reserved temperature monitoring hole 23, and each reserved temperature monitoring hole 23 is electrically connected to the temperature control system 3.

[0053] Furthermore, such as Figure 3 As shown, the plate 21 is provided with a plurality of spaced-apart inserts 211. The side of the inserts 211 near the rotary valve 1 is combined to form a heating end face. The rotary valve 1 is provided with a groove 12 that fits into the inserts 211.

[0054] Furthermore, such as Figure 3 As shown, the inserts 211 are distributed in a matrix. Each row of inserts 211 on the side is provided with a snap-fit ​​groove 212. The groove 12 is provided with a protrusion 13 that engages with the snap-fit ​​groove 212.

[0055] In one specific embodiment, the rotary valve electric heating device includes a rotary valve 1, an electric heating plate 2, a temperature control system 3, an insulation shell 4, and a temperature sensor 5. The heating end face of the electric heating plate 2 is arc-shaped and is respectively embedded on both sides of the rotary valve 1, keeping it coaxial with the rotor of the rotary valve 1. Multiple electric heating rods 22 are arranged inside the electric heating plate 2, spaced apart along the inner side of the plate body 21. Temperature monitoring holes 23 are reserved between adjacent electric heating rods 22, and each temperature monitoring hole 23 is electrically connected to the temperature control system 3 to achieve real-time monitoring of the internal temperature state of the electric heating plate 2. The electric heating plate 2 is fixed in the groove 12 formed on the outer surface of the rotary valve 1 by a casting process and cooperates with the insert 211. The combined surfaces between the inserts 211 together constitute the heating end face of the electric heating plate 2, with a gap of only 1mm, thereby ensuring efficient heat transfer between the electric heating plate 2 and the rotary valve 1, while avoiding local overheating caused by direct contact between the electric heating plate 2 and the shell of the rotary valve 1.

[0056] Meanwhile, the insulation shell 4 is wrapped around the outside of the mounting body formed by the rotary valve 1 and the electric heating plate 2 to reduce heat loss and improve overall insulation performance. The detection end of the temperature sensor 5 passes through the insulation shell 4 and the valve body of the rotary valve 1 in sequence, and finally inserts into the temperature measurement blind hole 11 pre-set inside the rotary valve 1. This allows it to directly obtain the true temperature value inside the rotary valve 1 shell, rather than just the temperature signal on the surface of the electric heating plate 2. The temperature sensor 5 is electrically connected to the temperature control system 3, which is also connected to the electric heating plate 2. When the temperature of the rotary valve 1 shell reaches the set value, the control system 3 sends a control signal to cut off the power to the electric heating plate 2 and stop heating. When the temperature drops below the set range, the power to the electric heating plate 2 is turned on again, thereby realizing dynamic closed-loop control of the temperature of the rotary valve 1 shell and maintaining it within a safe range for a long time.

[0057] During operation, the electric heating rod 22 evenly conducts heat to the plate 21 and then transfers it to the housing of the rotary valve 1 via the insert 211. To prevent damage to the electric heating rod 22 due to overheating, the temperature control system 3 controls the electric heating rod 22 in real time based on signals collected by the temperature monitoring port 23. Simultaneously, the temperature sensor 5 located inside the housing of the rotary valve 1 effectively avoids the errors of traditional attached detection methods, ensuring accurate monitoring of the temperature of the rotary valve 1 under actual operating conditions. Through this structure, the entire rotary valve electric heating device achieves efficient heat transfer and precise temperature control, ensuring a stable thermal environment for the rotary valve 1 during operation and preventing internal materials from melting or softening due to overheating, thereby improving the safety and reliability of the system.

[0058] In another embodiment, the electric heating plate 2 is cast from aluminum alloy. The electric heating rod 22 is pre-fixed inside the mold cavity before the electric heating plate 2 is cast, so that after casting is completed, the electric heating rod 22 can be stably embedded in the plate 21, and the heat generated by it can be evenly distributed and conducted to the entire electric heating plate 2, thereby improving the heat transfer efficiency and temperature uniformity of the heating end face of the rotary valve 1.

[0059] The temperature probe of the temperature sensor 5 adopts a spring-loaded connector structure. The temperature probe extends sequentially into the temperature measurement blind hole 11 through the insulation shell 4 and the valve body of the rotary valve 1, and is tightly fitted to the hole wall under the action of spring pressure without any gaps, thereby effectively ensuring the real-time and accuracy of temperature acquisition. When the temperature sensor 5 detects that the shell temperature of the rotary valve 1 reaches the preset threshold, the temperature sensor 5 transmits the detection signal to the temperature control system 3. The temperature control system 3 then outputs a control signal to cut off the power supply to the electric heating plate 2, causing the rotary valve 1 to enter the cooling stage. When the shell temperature drops to the set lower limit, the temperature sensor 5 transmits the signal to the temperature control system 3 again, driving the electric heating plate 2 to be powered on again and resume heating, so as to achieve dynamic maintenance of the shell temperature of the rotary valve 1 within a safe range.

[0060] In addition, the temperature control system 3 is connected to the reserved temperature monitoring hole 23 on the electric heating plate 2. The temperature probe configured inside the system can be directly inserted into the reserved temperature monitoring hole 23 to monitor the internal temperature of the electric heating plate 2 in real time. When the monitoring result shows that the electric heating plate 2 has reached the set temperature threshold, the temperature control system 3 will perform a power-off action to stop heating the electric heating rod 22; when the temperature drops to the lower limit, the circuit will be closed again to ensure that the electric heating plate 2 is always kept within the safe operating temperature range, thereby preventing the electric heating rod 22 from being damaged due to overheating.

[0061] In this embodiment, the insulation shell 4 adopts a square outer shell structure spliced ​​from multiple aluminum plates, which is fixed to the outside of the mounting body of the rotary valve 1 by bolts. Insulation cotton is filled between the insulation shell 4 and the valve body of the rotary valve 1 to form a highly efficient heat insulation layer. This effectively reduces heat loss during heating and isolates the insulation shell 4 from direct contact with the electric heating plate 2, thereby reducing energy consumption and improving safety. Simultaneously, the insulation cotton layer protects external operators from electric shock and burns.

[0062] Specifically, a rotary valve electric heating device also includes an explosion-proof junction box 6 and a main junction box 7. The main junction box 7 is used to connect to an external three-phase power supply. The external three-phase power is first connected to the main junction box 7, and then led out from the main junction box 7 through three three-core cables. Each three-core cable includes a grounding wire and is connected to three explosion-proof junction boxes 6 respectively. Each explosion-proof junction box 6 is electrically connected to a set of electric heating rods 22 inside the electric heating plate 2, so that the three sets of electric heating rods 22 can operate in combination according to a 380V delta connection, thereby ensuring that the electric heating plate 2 obtains a stable three-phase heating power. Each explosion-proof junction box 6 is equipped with a grounding terminal, which cooperates with the grounding wire of the corresponding three-core cable to achieve reliable grounding protection. Through the hierarchical configuration of the main junction box 7 and multiple explosion-proof junction boxes 6, the power access path not only meets the needs of three-phase balanced power supply, but also complies with the safety standards of explosion-proof areas, effectively avoiding safety hazards caused by electric sparks in high-temperature or flammable gas environments. At the same time, it achieves modular layout, which is convenient for installation and maintenance.

[0063] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A control method for a rotary valve electric heating device, characterized in that, An electric heating device for a rotary valve is provided, the rotary valve electric heating device comprising a rotary valve and an electric heating plate, the electric heating plate being connected to the rotary valve for heating the rotary valve, the control method comprising: Acquire a first temperature signal by means of a temperature probe arranged on an electric heating plate, and a second temperature signal by means of a temperature sensor arranged in a blind hole in the rotary valve housing; The first temperature signal and the second temperature signal are filtered respectively to obtain the first filtered temperature and the second filtered temperature, and the corresponding temperature difference value is calculated based on the first filtered temperature and the second filtered temperature. When the second filtered temperature is lower than the lower threshold of the preset target temperature range, a first control command is generated; when the second filtered temperature is higher than the upper threshold of the preset target temperature range, a second control command is generated. Determine whether the temperature difference value exceeds the temperature difference threshold. If it exceeds the temperature difference threshold, generate a third control command. If the temperature difference threshold is not exceeded, then determine whether the first filtered temperature exceeds the safe upper limit temperature. If it exceeds the safe upper limit temperature, then generate the fourth control command. When the first control command is detected and the second, third and fourth control commands are not detected, the operation of turning on the power supply of the electric heating plate is executed; when any one of the second, third or fourth control commands is detected, the operation of turning off the power supply of the electric heating plate is executed.

2. The control method for a rotary valve electric heating device according to claim 1, characterized in that, The step of generating a first control command when the second filtered temperature is lower than the lower threshold of the preset target temperature range, and generating a second control command when the second filtered temperature is higher than the upper threshold of the preset target temperature range, includes: A safe connection threshold is set below the lower threshold, and a safe disconnection threshold is set above the upper threshold. When the second filtered temperature is within the first numerical range between the safe turn-on threshold and the lower limit threshold, the first delay determination stage is entered. If the second filtered temperature remains within the first numerical range during the determination period of the first delay determination stage, a first control command is generated. When the second filter temperature is lower than the safe turn-on threshold, a first control command is immediately generated; When the second filtered temperature is within the second numerical range between the safety disconnection threshold and the upper limit threshold, the second delay determination stage is entered. If the second filtered temperature remains within the second numerical range during the determination period of the second delay determination stage, a second control command is generated. When the second filter temperature is higher than the safety disconnection threshold, a second control command is immediately generated.

3. The control method for a rotary valve electric heating device according to claim 2, characterized in that, The steps for generating the determination period in the first delay determination stage include: Calculate the first deviation between the second filtered temperature and the lower limit threshold, and determine the first initial determination period of the first delay determination stage based on the first deviation and the preset deviation mapping relationship. Based on the comparison relationship between the temperature difference value and the temperature difference threshold, the first initial determination period is corrected to generate a corresponding first corrected determination period; The first correction determination period is modified a second time by using the first historical period recorded in the previous control period to generate the determination period of the first delay determination stage. The steps for generating the determination period in the second delay determination stage include: Calculate the second deviation between the second filtered temperature and the upper limit threshold, and determine the second initial determination period of the second delay determination stage based on the second deviation and the preset deviation mapping relationship. Based on the comparison relationship between the temperature difference value and the temperature difference threshold, the second initial determination period is corrected to generate a corresponding second corrected determination period. The second correction determination period is modified a second time by using the second historical period recorded in the previous control period to generate the determination period for the second delay determination stage.

4. The control method for a rotary valve electric heating device according to claim 3, characterized in that, The step of performing a second correction on the first correction determination period using the first historical period recorded in the previous control period to generate the determination period for the first delay determination stage includes: Determine the first cycle ratio parameter between the first historical cycle and the first correction determination cycle; When the first cycle ratio parameter is less than 1, the first correction determination period is extended based on the first cycle ratio parameter to generate the determination period of the first delay determination stage. When the first cycle ratio parameter is greater than 1, the first correction determination cycle is shortened based on the first cycle ratio parameter to generate the determination cycle of the first delay determination stage. The step of performing a second correction on the second correction determination period using the second historical period recorded in the previous control period to generate the determination period for the second delay determination stage includes: Determine the second cycle ratio parameter between the second historical cycle and the second correction determination cycle; When the second cycle ratio parameter is less than 1, the second correction determination period is extended based on the second cycle ratio parameter to generate the determination period of the second delay determination stage. When the second period ratio parameter is greater than 1, the second correction determination period is shortened based on the second period ratio parameter to generate the determination period of the second delay determination stage.

5. The control method for a rotary valve electric heating device according to claim 1, characterized in that, In the step of determining whether the temperature difference value exceeds a temperature difference threshold, and generating a third control command if it does, the electric heating plate is provided with electric heating rods arranged in sequence, wherein each electric heating rod is defined as an independent electric heating area. The step further includes: Determine whether the temperature difference value exceeds a preset feedback value range, wherein the upper limit of the value range in the feedback value range is a temperature difference threshold. If so, then generate a third control command; If not and it is within the preset feedback value range, then the heating power in the independent electric heating area is pre-adjusted in sequence, and the temperature difference value after adjusting the heating power is recalculated. The previously obtained temperature difference value is compared with the temperature difference value after adjusting the heating power to generate a corresponding comparison result. Based on the comparison result, the electric heating independent area with a significant reduction in temperature difference value is determined as the target area. Adjust the heating power parameters of the target area until the temperature difference value drops below the lower limit of the feedback value range.

6. The control method for a rotary valve electric heating device according to claim 1, characterized in that, The steps for generating the safe upper limit temperature include: Determine a temperature difference reference value, wherein the temperature difference reference value is less than the temperature difference threshold, and calculate the difference offset between the temperature difference reference value and the temperature difference value; The difference offset is multiplied by a preset convergence coefficient to correct the preset baseline upper limit temperature and generate the corresponding first initial upper limit temperature. The slope of the temperature difference value within a preset time window is obtained, and the slope is multiplied by a preset slope coefficient to generate a corresponding slope correction amount. The first initial upper limit temperature is corrected based on the slope correction amount to generate a corresponding second initial upper limit temperature. Determine the upper limit of the material temperature resistance of the electric heating plate, compare the upper limit of the material temperature resistance with the preset minimum allowable upper limit, generate a corresponding comparison result, and clamp the second initial upper limit temperature according to the comparison result to generate a corresponding safe upper limit temperature.

7. A rotary valve electric heating device, characterized in that, include: Rotary valve (1); Two electric heating plates (2) are provided. The heating end faces of the two electric heating plates are respectively embedded on opposite sides of the rotary valve. The heating end faces are arc-shaped and keep the same axis as the rotor of the rotary valve. A temperature control system (3) is installed on one side of the electric heating plate (2) and electrically connected to a temperature probe provided on the electric heating plate (2) to obtain a first temperature signal of the electric heating plate (2); The heat insulation shell (4) is fitted with the mounting body, which is a structural component after the rotary valve (1) and the electric heating plate (2) are fitted together; Temperature sensor (5), the detection end of the temperature sensor (5) passes through the insulation shell (4) and the valve body of the rotary valve (1) in sequence, so as to connect with the temperature measurement blind hole (11) reserved in advance on the inner side of the rotary valve (1), and the temperature sensor (5) is electrically connected to the temperature control system (3).

8. The rotary valve electric heating device according to claim 7, characterized in that, The electric heating plate (2) includes: Plate(21); Multiple electric heating rods (22) are provided and arranged sequentially at intervals on the inner side of the plate (21). A reserved temperature monitoring hole (23) is provided between each two adjacent electric heating rods (22), and each reserved temperature monitoring hole (23) is electrically connected to the temperature control system (3).

9. The rotary valve electric heating device according to claim 8, characterized in that, The plate (21) is provided with a plurality of spaced inserts (211), and the side of the inserts (211) close to the rotary valve (1) is combined to form the heating end face. The rotary valve (1) is provided with a groove (12) that fits into the inserts (211).

10. The rotary valve electric heating device according to claim 9, characterized in that, The inserts (211) are distributed in a matrix. Each row of inserts (211) on the side is provided with a snap-fit ​​groove (212). The groove (12) is provided with a protrusion (13) that snaps into the snap-fit ​​groove (212).

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