A cross-coating drying furnace body inside and outside differential air supply circulation system

Abstract

The application provides a horizontal coating and drying furnace body inside and outside differential air supply circulation system, relates to the technical field of horizontal coating and drying furnace, and comprises the following steps: outputting initial cooperative control instructions through a drying process reduced-order model; establishing a closed circulation air flow path of the body cavity, and outputting an internal air supply state signal; adjusting the external air supply parameters, outputting an external air supply state signal; recovering waste heat of the exhaust gas of the drying furnace, adjusting fresh air distribution, and outputting a fresh air state feedback signal. The application realizes differential and accurate control of the temperature field inside and outside the body and the solvent evaporation rate by predicting the temperature field in real time based on the drying process reduced-order model and cooperatively generating internal and external loop control instructions, adaptively compensating the external air volume and heating power according to the real-time occupancy rate of internal air flow kinetic energy to maintain the stability and temperature uniformity of the horizontal air curtain, and effectively solves the curing defect problem of the temperature rise lag area.

Description

Technical Field

[0001] This invention relates to the field of horizontal coating drying oven technology, and more particularly to a differentiated air circulation system for the interior and exterior of a horizontal coating drying oven. Background Technology

[0002] The horizontal coating drying oven is a core thermal equipment in the coating production line used for paint film curing, typically employing a horizontal tunnel structure. The oven body is enclosed by insulated walls, and its interior is often divided into heating and insulation zones along its length. Workpieces continuously pass through the oven chamber laterally via suspended conveyor chains or floor skids. Convection heating is the primary method of heating within the oven, and an air circulation system repeatedly delivers hot air generated by burners or electric heaters to the workpiece surface for heat exchange. Its main components include a steel insulated shell, heating devices, conveying channels, and airflow organization components.

[0003] The air circulation system is the medium transfer loop for forced convection heat transfer within the drying oven. It typically consists of a circulating fan, a filter, a heater, an air supply duct, a return air duct, and a set of nozzles. During system operation, the circulating fan draws air into the oven, filters it, and sends it to the heater for heating. The air is then distributed through the main duct to slotted, perforated, or nozzle-type air jets located on the top, side, or bottom walls, spraying hot air onto the workpiece surface for forced convection heat transfer. The heat-exchanged airflow converges in the return air duct and returns to the fan inlet, forming a closed loop. The system also includes separate fresh air intake and exhaust branches to maintain the solvent vapor concentration within the allowable range.

[0004] Existing coating drying oven air circulation systems often suffer from insufficient heat transfer efficiency or ineffective hot airflow, resulting in actual heating rates that are significantly lower than the process requirements. Summary of the Invention

[0005] This invention provides a differentiated air circulation system for the interior and exterior of a horizontally mounted painting drying oven, which solves the defects of existing painting drying oven air circulation systems, such as the inability of hot air to reach the oven effectively or insufficient convective heat transfer efficiency.

[0006] On one hand, this invention provides a differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven, comprising: a multi-source sensing and edge computing module, an internal air circulation processing module, an external air circulation processing module, and a fresh air supply and heat recovery module; the multi-source sensing and edge computing module is used to collect infrared thermal images of the vehicle body, oven atmosphere parameters, and oven static pressure, and outputs initial collaborative control commands through a reduced-order model of the drying process; the internal air circulation processing module is used to establish a closed-loop airflow path in the cavity inside the vehicle body, inject hot air into the interior of the vehicle body through retractable air nozzles under the vehicle, and outputs an internal air supply status signal based on the internal parameter adjustment amount in the initial collaborative control command; the external air circulation processing module is used to drive a horizontally mounted air curtain around the vehicle body and provide external heated airflow, and adjusts the external air supply parameters based on the internal air supply status signal, and outputs an external air supply status signal; the fresh air supply and heat recovery module is used to recover waste heat from the exhaust gas of the drying oven, supply preheated fresh air to the internal and external air circulation processing modules, adjust the fresh air distribution according to the external air supply status signal, and output a fresh air status feedback signal.

[0007] According to the present invention, a differentiated air circulation system for the interior and exterior of a horizontally mounted painting drying oven includes a multi-source sensing and edge computing module comprising an infrared thermal image acquisition unit, a data fusion and preprocessing unit, a model inference unit, and a collaborative instruction generation unit. The infrared thermal image acquisition unit acquires infrared thermal images of the vehicle body and outputs the thermal image data. The data fusion and preprocessing unit cleans and extracts features from the thermal image data, atmosphere parameters, and static pressure, and outputs standardized input data. The model inference unit runs a reduced-order model of the drying process using the standardized input data as input and outputs predicted temperature field data and internal and external loop control parameters. The collaborative instruction generation unit performs collaborative logic judgment on the predicted temperature field data and internal and external loop control parameters, and outputs initial collaborative control instructions.

[0008] According to the present invention, a differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven is provided. The steps for constructing a reduced-order model of the drying process include: A physical information neural network model is constructed based on complete working condition data of the historical drying process. The physical information neural network model takes the measurable variables in the complete working condition data as input and the predicted temperature and solvent residual rate of each discrete node of the vehicle body as output. Construct the total loss function; The physical information neural network model is trained offline using complete working condition data, so that the total loss function converges to below a preset threshold, and the trained model is obtained. The trained model is compressed and quantized to obtain a reduced-order model of the drying process that can run in real time in an edge computing gateway; The reduced-order model of the drying process is deployed to the model inference unit, which outputs temperature field prediction data and internal and external loop control parameters.

[0009] According to the present invention, a differentiated air circulation system for the interior and exterior of a horizontally mounted painting drying oven includes a step in which the collaborative instruction generation unit performs collaborative logic judgment on temperature field prediction data and internal and external loop control parameters, comprising: The predicted heating slope of each discrete node is compared with the preset lower limit threshold of the process-allowed heating slope to identify the hysteresis region where the heating slope is lower than the lower limit threshold. When a lag region is detected, the internal parameter adjustment amount that increases the pulse frequency and internal circulating air volume is selected from the internal loop control parameters, and the external parameter adjustment amount that decreases the external circulating air volume and allows the heater power to be increased is selected from the external loop control parameters, and the corresponding fresh air distribution adjustment amount is generated. The internal parameter adjustment amount, external parameter adjustment amount, and fresh air distribution adjustment amount are encapsulated into an initial collaborative control command and output to the command parsing unit.

[0010] According to the present invention, a differentiated air circulation system for the interior and exterior of a horizontally mounted painting drying oven includes an internal air circulation processing module comprising an instruction parsing unit, an air volume adjustment unit, a pulse frequency adjustment unit, and an internal status output unit. The instruction parsing unit is used to parse the internal air volume setpoint and pulse frequency setpoint from the initial coordinated control instruction and output an internal adjustment instruction. The air volume adjustment unit is used to adjust the speed and air volume of the variable frequency centrifugal fan according to the internal air volume setpoint and output the actual air volume value. The pulse frequency adjustment unit is used to dynamically correct the pulse frequency based on the actual air volume value and control the pulse turbulence damper, outputting the actual pulse frequency and internal airflow state parameters. The internal status output unit is used to generate an internal air supply status signal based on the actual air volume value, the actual pulse frequency, and the internal airflow state parameters.

[0011] According to the present invention, a differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven includes a step of dynamically correcting the pulse frequency using a pulse frequency adjustment unit, comprising: Using the actual air volume value as the input parameter, the pre-calibrated air volume frequency mapping table is consulted to obtain the basic pulse frequency correction value; Obtain the airflow pressure feedback signal of the current internal cavity of the vehicle body, and calculate the deviation between the basic pulse frequency correction value and the ideal pulse frequency under actual airflow pressure conditions; The deviation is adjusted using a PID closed-loop control to obtain the final pulse frequency correction value; The final pulse frequency correction value is superimposed with the basic pulse frequency correction value to generate a pulse turbulence damper control signal, which drives the pulse turbulence damper to move. The actual pulse frequency and internal airflow state parameters after the pulse turbulence damper is activated are collected and output to the internal state output unit.

[0012] According to the present invention, a differentiated air circulation system for the interior and exterior of a horizontally mounted painting drying oven includes an external air circulation processing module comprising an internal state analysis unit, an external air volume adjustment unit, a heating power adjustment unit, and an external state output unit. The internal state analysis unit is used to analyze the external air volume compensation value and the heating power compensation value based on the internal air circulation state signal and output an external adjustment command. The external air volume adjustment unit is used to adjust the external circulation fan according to the external air volume compensation value and output the actual external air volume value. The heating power adjustment unit is used to feedforward and correct the heating power setpoint based on the actual external air volume value and adjust the heater power, outputting the actual heating power and external airflow temperature parameters. The external state output unit is used to generate an external air circulation state signal based on the actual external air volume value, the actual heating power, and the external airflow temperature parameters.

[0013] According to the present invention, a differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven includes the following steps in which the internal state analysis unit analyzes the external air volume compensation value and the heating power compensation value: Extract the actual air volume value, actual pulse frequency, and internal airflow status parameters from the internal air supply status signal; Read the external parameter adjustment amounts contained in the initial cooperative control command; Using the actual air volume and actual pulse frequency as inputs, calculate the real-time occupancy rate of the internal loop on the total airflow energy; The real-time occupancy rate is compared with the preset target occupancy rate in the external parameter adjustment to obtain the occupancy rate deviation. The external air volume compensation value is calculated based on the occupancy rate deviation. The compensation direction is to reduce the external air volume in order to release the air kinetic energy for use by the internal circuit. The heating power compensation value is calculated based on the external air volume compensation value and the real-time occupancy rate to compensate for the possible drop in external airflow temperature due to the reduction in external air volume. The external air volume compensation value and the heating power compensation value are encapsulated into external adjustment commands and output to the external air volume adjustment unit and the heating power adjustment unit.

[0014] According to the present invention, a differentiated air circulation system for the interior and exterior of a horizontally mounted painting drying oven includes a fresh air supply and heat recovery module comprising an external state analysis unit, an exhaust heat recovery unit, a fresh air preheating unit, a fresh air distribution and adjustment unit, and a fresh air feedback output unit. The external state analysis unit is used to analyze the fresh air distribution ratio command based on the external air supply state signal and output a fresh air adjustment command. The exhaust heat recovery unit is used to recover the waste heat from the exhaust gas emitted by the drying oven and output a recoverable heat value. The fresh air preheating unit is used to preheat the fresh air based on the recoverable heat value and output the temperature and flow parameters of the preheated air. The fresh air distribution and adjustment unit is used to adjust the opening of the fresh air valves leading to the internal and external loops based on the temperature and flow parameters of the preheated air and the fresh air distribution ratio command, and output the actual fresh air distribution flow rate. The fresh air feedback output unit is used to generate a fresh air state feedback signal based on the actual fresh air distribution flow rate.

[0015] According to the present invention, a differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven includes a fresh air feedback output unit that generates a fresh air status feedback signal, comprising the following steps: Receive the actual fresh air distribution flow rate output by the fresh air distribution and regulation unit. The actual fresh air distribution flow rate includes the actual fresh air flow rate entering the internal loop and the actual fresh air flow rate entering the external loop. The actual fresh air flow entering the internal loop is compared with the preset fresh air demand value of the internal loop to calculate the internal fresh air satisfaction rate. The actual fresh air flow entering the external loop is compared with the preset fresh air demand value of the external loop to calculate the external fresh air satisfaction rate. The heat recovery efficiency is calculated by comparing the recoverable heat value with the preset maximum recoverable heat value. The temperature of the preheated air is compared with the preset preheating target temperature to calculate the preheating quality index. The internal fresh air satisfaction rate, external fresh air satisfaction rate, heat recovery efficiency, and preheating quality indicators are encapsulated into fresh air status feedback signals and output to the data fusion and preprocessing unit of the multi-source sensing and edge computing module.

[0016] This invention provides a differentiated air circulation system for the interior and exterior of a horizontally mounted coating drying oven. It predicts the temperature field in real time based on a reduced-order model of the drying process and collaboratively generates control commands for the internal and external loops. By establishing a closed-loop airflow path and dynamically correcting the pulse frequency to enhance convective heat transfer within the internal cavity, it adaptively compensates for external airflow and heating power based on the real-time occupancy rate of the internal airflow to maintain the stability and temperature uniformity of the horizontal air curtain. It also recovers waste heat from exhaust gases and distributes preheated fresh air to the internal and external loops as needed. This achieves differentiated and precise control of the temperature field and solvent evaporation rate inside and outside the vehicle body, effectively solving the curing defect problem in areas with lag in temperature rise. While ensuring consistent coating quality, it also reduces the overall energy consumption of the system. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven, provided in an embodiment of the present invention. Figure 2 This is a flowchart of constructing a reduced-order model of the drying process provided in an embodiment of the present invention; Figure 3 This is a flowchart of the pulse frequency adjustment unit dynamically correcting the pulse frequency provided in the embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] The following is combined Figures 1-3 This invention describes a differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven.

[0021] like Figures 1-3 As shown in the figure, the present invention provides a differentiated air circulation system for the interior and exterior of a horizontally mounted painting drying oven, comprising: a multi-source sensing and edge computing module, an internal air circulation processing module, an external air circulation processing module, and a fresh air supply and heat recovery module.

[0022] The multi-source sensing and edge computing module is used to acquire infrared thermal images of the vehicle body, furnace atmosphere parameters, and furnace static pressure, and outputs initial collaborative control commands through a reduced-order model of the drying process. Specifically, the infrared thermal images of the vehicle body are acquired by infrared thermal imagers installed at specific locations within the drying furnace, obtaining the two-dimensional temperature distribution of the vehicle surface; the furnace atmosphere parameters, including temperature, humidity, and solvent concentration, are acquired by a gas sensor array distributed within the furnace; the furnace static pressure is obtained by a static pressure sensor at measurement points in the furnace air duct; and the reduced-order model of the drying process is a simplified real-time prediction model based on a physical information neural network, trained offline and compressed and quantized at the edge, enabling rapid inference on the edge computing gateway.

[0023] The multi-source sensing and edge computing module includes an infrared thermal image acquisition unit, a data fusion and preprocessing unit, a model inference unit, and a collaborative instruction generation unit. The infrared thermal image acquisition unit acquires infrared thermal images of the vehicle body and outputs thermal image data. The thermal image data is a two-dimensional temperature matrix, with each pixel corresponding to the temperature value at a specific location on the vehicle surface. The data fusion and preprocessing unit cleans and extracts features from the thermal image data, atmosphere parameters, and static pressure, and outputs standardized input data. Data cleaning includes moving average filtering of sensor data such as thermocouples, non-uniformity correction of infrared thermal image data, and outlier removal. Feature extraction includes extracting spatial features such as the highest temperature region, average temperature, and temperature gradient from the thermal image, as well as the time change rate of atmosphere parameters. Standardized input data refers to feature vectors that have undergone normalization or standardization and have a unified scale. The model inference unit runs a reduced-order model of the drying process using the standardized input data as input and outputs predicted temperature field data and internal / external loop control parameters. The steps for constructing the order reduction model of the drying process include: A physical information neural network model is constructed based on complete operating data of the historical drying process. The physical information neural network model takes the measurable variables in the complete operating data as input and the predicted temperature values ​​and solvent residual rate values ​​of each discrete node of the vehicle body as output. The complete operating data includes the measured temperature values ​​of each discrete node of the vehicle body at various time points during the drying process, infrared thermal image sequences, furnace atmosphere parameters (temperature, humidity, solvent concentration), furnace static pressure, air supply parameters (air volume, air temperature, pulse frequency), heating power, etc., collected from the actual production line. Measurable variables include directly measurable process variables such as air supply parameters, furnace atmosphere parameters, and static pressure. Discrete nodes refer to the nodes after dividing the finite element mesh of the vehicle body, which are used to characterize the temperature distribution of key areas of the vehicle body. The physical information neural network model is a neural network with embedded physical equation constraints. Its loss function includes not only data errors but also residuals of the control equations.

[0024] Construct the total loss function; The physical information neural network model is trained offline using complete working condition data, so that the total loss function converges to below a preset threshold, and the trained model is obtained. The trained model is compressed and quantized to obtain a reduced-order drying process model that can run in real time in the edge computing gateway. The compression and quantization process includes operations such as network pruning, weight quantization, and knowledge distillation to reduce the number of model parameters and computational load, so that its inference time meets the real-time requirements of the edge computing gateway.

[0025] The reduced-order model of the drying process is deployed to the model inference unit, which outputs temperature field prediction data and internal and external loop control parameters.

[0026] The coordinated control command generation unit performs coordinated logic judgments on temperature field prediction data and internal / external loop control parameters, and outputs initial coordinated control commands. These initial coordinated control commands are a set of adjustment quantities preliminarily determined based on the predicted temperature field and lag region identification, used to coordinate internal air supply, external air supply, and fresh air distribution, serving as the benchmark for subsequent control. The steps for outputting the initial coordinated control commands include: The predicted heating slope of each discrete node is compared with the preset lower limit threshold of the process-allowed heating slope to identify the lag region where the heating slope is lower than the lower limit threshold. The predicted heating slope is calculated from the derivative of the temperature change of each discrete node with time in the temperature field prediction data. The lower limit threshold of the process-allowed heating slope is the minimum temperature rise rate preset according to the curing characteristics of the coating. If it is lower than this threshold, the coating will not cure sufficiently.

[0027] When a lag region is detected, the internal parameter adjustment amount that increases the pulse frequency and internal circulating air volume is selected from the internal loop control parameters, and the external parameter adjustment amount that decreases the external circulating air volume and allows for an increase in heater power is selected from the external loop control parameters, and the corresponding fresh air distribution adjustment amount is generated. The internal loop control parameters are the suggested control amounts for the internal air supply circulation loop output by the reduced-order model of the drying process, including the setting range of internal air volume and pulse frequency. The external loop control parameters are the suggested control amounts for the external air supply loop output by the model, including the setting range of external air volume and heating power. The fresh air distribution adjustment amount refers to the amount of fresh air supply ratio reallocated in order to balance the airflow demand of the internal and external loops.

[0028] The internal parameter adjustment amount, external parameter adjustment amount, and fresh air distribution adjustment amount are encapsulated into an initial collaborative control command and output to the command parsing unit.

[0029] The internal air circulation processing module is used to establish a closed-loop airflow path within the vehicle body's internal cavities and inject hot air into the vehicle body through retractable air nozzles at the bottom of the vehicle. Based on the internal parameter adjustments in the initial coordinated control commands, it outputs an internal airflow status signal. The closed-loop airflow path refers to the retractable air nozzles at the bottom of the vehicle extending into the vehicle body and forming a sealed fit with its internal cavities. An internal circulation fan drives the airflow to form a closed loop between the internal cavities and the circulation ducts, reducing heat loss and solvent leakage. The retractable air nozzles at the bottom of the vehicle are adjustable air supply devices that fit snugly against openings at the bottom of the vehicle body; they are equipped with an airflow regulating valve and a pulse turbulence damper.

[0030] The internal air circulation processing module includes an instruction parsing unit, an airflow regulation unit, a pulse frequency regulation unit, and an internal status output unit. The instruction parsing unit parses the internal airflow setpoint and pulse frequency setpoint from the initial coordinated control instruction and outputs the internal regulation instruction. The internal regulation instruction contains the digital signals of the internal airflow setpoint and pulse frequency setpoint, and is sent to the corresponding actuator via the fieldbus.

[0031] The airflow regulation unit adjusts the speed and airflow of the variable frequency centrifugal fan according to the internal airflow setpoint and outputs the actual airflow value. The variable frequency centrifugal fan is driven by a frequency converter, and the airflow regulation uses a PID control algorithm to ensure that the actual airflow quickly tracks the setpoint; the actual airflow value is measured in real time by an anemometer installed in the internal circulating air duct. The pulse frequency regulation unit dynamically corrects the pulse frequency based on the actual airflow value and controls the pulse turbulence damper, outputting the actual pulse frequency and internal airflow state parameters.

[0032] The steps for dynamically correcting the pulse frequency include: Using the actual airflow value as the input parameter, the base pulse frequency correction value is obtained by querying the pre-calibrated airflow frequency mapping table. The pre-calibrated airflow frequency mapping table is created through experiments to obtain the optimal pulse frequency under different airflows, so as to achieve the best airflow disturbance effect; the base pulse frequency correction value is obtained by interpolation from the table based on the current actual airflow.

[0033] The airflow pressure feedback signal of the current internal cavity of the vehicle body is acquired. This airflow pressure feedback signal is collected by a micro differential pressure sensor installed in the internal cavity of the vehicle body, reflecting the pressure changes of the internal pulsating airflow. The deviation between the base pulse frequency correction value and the ideal pulse frequency under actual airflow pressure conditions is calculated. The ideal pulse frequency is determined based on the airflow pressure-frequency model, at which the internal cavity can resonate and enhance the turbulence effect. The formula for calculating the deviation is expressed as: , in, The deviation between the base pulse frequency correction value and the ideal pulse frequency. The base pulse frequency correction value is obtained from the air volume frequency mapping table; To achieve the ideal pulse frequency, based on the airflow pressure feedback signal From the pressure-frequency model Provided.

[0034] The deviation is adjusted using a PID closed-loop control to obtain the final pulse frequency correction value. The PID control algorithm is expressed as follows: , in, This is the final pulse frequency correction value. These are the proportional, integral, and differential gain coefficients, respectively, and t is time.

[0035] The final pulse frequency correction value is superimposed on the basic pulse frequency correction value to generate a pulse turbulence damper control signal, which drives the pulse turbulence damper to operate. The frequency of the superimposed control signal is... This signal is converted into a pulse width modulation (PWM) driven pulse turbulence damper. The pulse turbulence damper is a high-speed switching valve or a swing baffle that generates pulse jets by periodically changing the area of ​​the airflow channel.

[0036] The actual pulse frequency and internal airflow state parameters after the pulse turbulence damper actuates are collected and output to the internal status output unit. The actual pulse frequency is obtained by detecting the damper actuation cycle through a position sensor, and the internal airflow state parameters, including the average temperature and pressure pulsation amplitude of the internal cavity, are collected by corresponding sensors.

[0037] The internal status output unit is used to generate an internal air supply status signal based on the actual air volume value, the actual pulse frequency, and the internal airflow status parameters.

[0038] The external air circulation processing module drives the horizontal air curtain around the vehicle body and provides external heated airflow. It also adjusts the external air supply parameters based on the internal air supply status signal and outputs the external air supply status signal. The horizontal air curtain is formed by blowing hot air laterally at a certain angle through air vents arranged on both sides of the vehicle body, creating an airflow curtain that covers the perimeter of the vehicle body. This is used to heat the outer surface of the vehicle body and insulate it from cold outside air.

[0039] The external air circulation processing module includes an internal status analysis unit, an external airflow adjustment unit, a heating power adjustment unit, and an external status output unit. The internal status analysis unit analyzes the internal airflow status signal to determine the external airflow compensation value and the heating power compensation value, and outputs an external adjustment command. The external airflow compensation value is a negative increment, indicating the amount of external airflow that needs to be reduced; the heating power compensation value is a positive increment, used to compensate for any insufficient heating that may result from the reduction in external airflow. The steps for outputting the external adjustment command include: Extract the actual air volume, actual pulse frequency, and internal airflow status parameters from the internal air supply status signal.

[0040] Read the external parameter adjustments contained in the initial coordinated control command. These adjustments include the target reduction in external airflow and the maximum allowable increase in heating power.

[0041] Using the actual air volume and actual pulse frequency as inputs, the real-time utilization rate of the internal loop on the total airflow energy is calculated, expressed by the formula: , in, This represents the actual internal airflow volume. The internal circuit pneumatic head is obtained based on the internal fan characteristic curve and measured static pressure. This represents the current external airflow volume. It is an external circuit pneumatic pressure head.

[0042] Total airflow kinetic energy refers to the sum of the kinetic energy of the circulating air in the system, which can be calculated from the total air volume and air pressure; the real-time occupancy rate of the internal loop is calculated based on the internal air volume and air pressure combined with the fan characteristic curve.

[0043] The real-time occupancy rate is compared with the preset target occupancy rate in the external parameter adjustment to obtain the occupancy rate deviation. The target occupancy rate is the proportion of internal loop airflow energy that should be allocated according to process requirements. The room method for calculating the occupancy rate deviation is as follows: , in, Due to occupancy deviation, The preset target occupancy rate.

[0044] The external airflow compensation value is calculated based on the occupancy rate deviation. The compensation direction is to reduce the external airflow to release airflow energy for use in the internal circuit. The formula for calculating the external airflow compensation value is: , in, The external air volume compensation value is α, which is the compensation coefficient (0 < α ≤ 1). The negative sign indicates a reduction in the external air volume.

[0045] The heating power compensation value is calculated based on the external airflow compensation value and the real-time occupancy rate to compensate for the potential drop in external airflow temperature due to reduced external airflow. The formula for calculating the heating power compensation value is: , in, This is the heating power compensation value. ρ is the specific heat capacity of air, and ρ is the density of air. Set the temperature for the external airflow. This refers to the inlet air temperature of the external circuit.

[0046] The external air volume compensation value and the heating power compensation value are encapsulated into external adjustment commands and output to the external air volume adjustment unit and the heating power adjustment unit.

[0047] The external airflow control unit adjusts the external circulating fan according to the external airflow compensation value and outputs the actual external airflow value. The external circulating fan is a variable frequency centrifugal fan, and the actual external airflow value is measured by an anemometer.

[0048] The heating power adjustment unit is used to feedforward correct the heating power setpoint based on the actual external airflow value, and adjust the heater power, outputting the actual heating power and external airflow temperature parameters. The feedforward correction is based on the airflow-power relationship curve to quickly compensate for the impact of airflow changes on temperature; the heater is an electric heating or gas heating module, and the power is adjusted by a thyristor or proportional valve.

[0049] The external status output unit is used to generate an external air supply status signal based on the actual external air volume, actual heating power, and external airflow temperature parameters.

[0050] The fresh air supply and heat recovery module recovers waste heat from the exhaust gas of the drying furnace and supplies preheated fresh air to both the internal and external air circulation modules. It also adjusts the fresh air distribution based on the external air circulation status signal and outputs a fresh air status feedback signal. Waste heat recovery is achieved using a gas-to-gas heat exchanger, where fresh air and exhaust gas exchange heat to increase the fresh air temperature.

[0051] The fresh air supply and heat recovery module includes an external status analysis unit, an exhaust heat recovery unit, a fresh air preheating unit, a fresh air distribution and adjustment unit, and a fresh air feedback output unit. The external status analysis unit analyzes the external air supply status signal to determine the fresh air distribution ratio and outputs a fresh air adjustment command. The analysis process is based on preset rules; for example, when the external loop airflow decreases, more fresh air is allocated to the internal loop.

[0052] The waste gas heat recovery unit is used to recover the waste heat from the exhaust gas emitted by the drying furnace and outputs a recoverable heat value. The recoverable heat value is calculated through heat balance based on the waste gas temperature and flow rate.

[0053] The fresh air preheating unit is used to preheat fresh air based on the recoverable heat value and outputs the temperature and flow rate parameters of the preheated air. Fresh air preheating uses plate or tubular heat exchangers, where fresh air is drawn in from the environment, filtered, and exchanges heat with exhaust gas.

[0054] The fresh air distribution and regulation unit is used to adjust the opening degree of the fresh air valves leading to the internal and external circuits according to the temperature and flow parameters of the preheated air and the fresh air distribution ratio command, and outputs the actual fresh air distribution flow rate. The fresh air valve is an electrically adjustable valve, which can adjust the opening degree from 0-100% and is equipped with a flow meter.

[0055] The fresh air feedback output unit is used to generate a fresh air status feedback signal based on the actual fresh air distribution flow rate. The steps include: Receive the actual fresh air distribution flow rate output from the fresh air distribution and regulation unit. The actual fresh air distribution flow rate includes the actual fresh air flow rate entering the internal loop and the actual fresh air flow rate entering the external loop.

[0056] The actual fresh air flow entering the internal loop is compared with the preset fresh air demand value of the internal loop to calculate the internal fresh air satisfaction rate, expressed by the formula: , in, To ensure the internal fresh air supply satisfaction rate, The actual fresh air flow rate entering the internal circuit. Preset fresh air demand values ​​for internal circuits.

[0057] The preset fresh air demand value for the internal loop is a set value calculated in advance based on the air volume ratio of the internal circulation and the minimum fresh air volume required to maintain the internal atmosphere.

[0058] The actual fresh air flow rate entering the external loop is compared with the preset fresh air demand value of the external loop to calculate the external fresh air satisfaction rate, expressed by the formula: , in, To ensure the external fresh air supply satisfaction rate, The actual fresh air flow rate entering the external circuit. The preset fresh air demand value for the external loop is a set value calculated in advance based on the proportion of external circulating air volume and the minimum fresh air volume required to maintain the external atmosphere.

[0059] The recoverable heat value is compared with the preset maximum recoverable heat value to calculate the heat recovery efficiency, expressed by the formula: , in, For heat recovery efficiency, The recoverable heat value output by the waste gas heat recovery unit. This is the theoretical maximum recoverable heat value calculated based on the total exhaust gas emissions and the heat exchanger design parameters.

[0060] The preheated air temperature is compared with the preset preheating target temperature to calculate the preheating quality index, expressed by the formula: , in, For preheating quality indicators, This refers to the actual temperature of the preheated air. The preset preheating target temperature is the preheated fresh air temperature value based on the process requirements.

[0061] The internal fresh air fulfillment rate, external fresh air fulfillment rate, heat recovery efficiency, and preheating quality indicators are encapsulated into a fresh air status feedback signal, which is then output to the data fusion and preprocessing unit of the multi-source sensing and edge computing module. This fresh air status feedback signal is used for closed-loop correction of subsequent control decisions, ensuring the system operates in its optimal state.

[0062] In summary, the present invention provides a differentiated air circulation system for the interior and exterior of a horizontally mounted coating drying oven. This system predicts the temperature field in real time based on a reduced-order model of the drying process and collaboratively generates control commands for the internal and external loops. It enhances convective heat transfer within the internal cavity by establishing a closed-loop airflow path and dynamically correcting the pulse frequency. It adaptively compensates for external airflow and heating power based on the real-time occupancy rate of the internal airflow to maintain the stability and temperature uniformity of the horizontal air curtain. It also recovers waste heat from exhaust gases and distributes preheated fresh air to the internal and external loops as needed. This achieves differentiated and precise control of the temperature field and solvent evaporation rate inside and outside the vehicle body, effectively solving the curing defect problem in areas with lag in temperature rise. While ensuring consistent coating quality, it also reduces the overall energy consumption of the system.

[0063] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods of various embodiments or some parts of embodiments.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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; and these 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 the present invention.

Claims

1. A differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven, characterized in that, include: The multi-source sensing and edge computing module is used to collect infrared thermal images of the vehicle body, furnace atmosphere parameters and furnace static pressure, and output initial collaborative control commands through a reduced-order model of the drying process; The internal air circulation processing module is used to establish a closed-loop airflow path in the cavity inside the vehicle body, and inject hot air into the interior of the vehicle body through the telescopic air nozzles under the vehicle body. Based on the internal parameter adjustment amount in the initial collaborative control command, it outputs an internal air circulation status signal. The external air circulation processing module is used to drive the horizontally placed air curtain around the vehicle body and provide external heated airflow, and adjust the external air supply parameters based on the internal air supply status signal, and output the external air supply status signal. The fresh air supply and heat recovery module is used to recover the waste heat from the exhaust gas of the drying oven, supply preheated fresh air to the internal air circulation processing module and the external air circulation processing module, adjust the fresh air distribution according to the external air supply status signal, and output a fresh air status feedback signal.

2. The differentiated air circulation system for the interior and exterior of a horizontally positioned painting and drying oven according to claim 1, characterized in that, The multi-source sensing and edge computing module includes an infrared thermal imaging acquisition unit, a data fusion and preprocessing unit, a model inference unit, and a collaborative instruction generation unit. The infrared thermal imaging acquisition unit acquires infrared thermal images of the vehicle body and outputs thermal image data. The data fusion and preprocessing unit cleans and extracts features from the thermal image data, atmosphere parameters, and static pressure, and outputs standardized input data. The model inference unit runs a reduced-order model of the drying process using the standardized input data as input and outputs temperature field prediction data and internal and external loop control parameters. The collaborative instruction generation unit performs collaborative logic judgment on the temperature field prediction data and internal and external loop control parameters and outputs initial collaborative control instructions.

3. The differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven according to claim 2, characterized in that, The steps for constructing a reduced-order model of the drying process include: A physical information neural network model is constructed based on complete working condition data of the historical drying process. The physical information neural network model takes the measurable variables in the complete working condition data as input and the predicted temperature and solvent residual rate of each discrete node of the vehicle body as output. Construct the total loss function; The physical information neural network model is trained offline using the complete working condition data, so that the total loss function converges to below a preset threshold, and the trained model is obtained. The trained model is compressed and quantized to obtain a reduced-order model of the drying process that can run in real time in an edge computing gateway; The reduced-order model of the drying process is deployed to the model inference unit, and the model inference unit outputs the temperature field prediction data and the internal and external loop control parameters.

4. The differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven according to claim 3, characterized in that, The steps of the collaborative instruction generation unit in performing collaborative logic judgment on the temperature field prediction data and the internal and external loop control parameters include: The predicted heating slope of each discrete node is compared with the preset lower limit threshold of the process-allowed heating slope to identify the hysteresis region where the heating slope is lower than the lower limit threshold. When a lag region is detected, the internal parameter adjustment amount that increases the pulse frequency and internal circulating air volume is selected from the internal loop control parameters, and the external parameter adjustment amount that decreases the external circulating air volume and allows the heater power to be increased is selected from the external loop control parameters, and the corresponding fresh air distribution adjustment amount is generated. The internal parameter adjustment amount, external parameter adjustment amount, and fresh air distribution adjustment amount are encapsulated into the initial collaborative control command and output to the command parsing unit.

5. The differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven according to claim 1, characterized in that, The internal air circulation processing module includes an instruction parsing unit, an air volume adjustment unit, a pulse frequency adjustment unit, and an internal status output unit. The instruction parsing unit is used to parse the internal air volume setpoint and pulse frequency setpoint from the initial coordinated control instruction and output the internal adjustment instruction. The air volume adjustment unit is used to adjust the speed and air volume of the variable frequency centrifugal fan according to the internal air volume setpoint and output the actual air volume value. The pulse frequency adjustment unit is used to dynamically correct the pulse frequency based on the actual air volume value, control the pulse turbulence damper to operate, and output the actual pulse frequency and internal airflow state parameters; the internal state output unit is used to generate an internal air supply state signal based on the actual air volume value, the actual pulse frequency, and the internal airflow state parameters.

6. The differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven according to claim 5, characterized in that, The steps for the pulse frequency adjustment unit to dynamically correct the pulse frequency include: Using the actual air volume value as the input parameter, the pre-calibrated air volume frequency mapping table is queried to obtain the basic pulse frequency correction value; Obtain the airflow pressure feedback signal of the current internal cavity of the vehicle body, and calculate the deviation between the basic pulse frequency correction value and the ideal pulse frequency under actual airflow pressure conditions; The deviation is adjusted using a PID closed-loop control to obtain the final pulse frequency correction value; The final pulse frequency correction value is superimposed with the basic pulse frequency correction value to generate a pulse turbulence damper control signal, which drives the pulse turbulence damper to operate. The actual pulse frequency and internal airflow state parameters after the pulse turbulence damper is activated are collected and output to the internal state output unit.

7. The differentiated air circulation system for the interior and exterior of a horizontally positioned painting and drying oven according to claim 1, characterized in that, The external air circulation processing module includes an internal state analysis unit, an external airflow adjustment unit, a heating power adjustment unit, and an external state output unit. The internal state analysis unit is used to analyze the external airflow compensation value and the heating power compensation value based on the internal airflow state signal and output an external adjustment command. The external airflow adjustment unit is used to adjust the external circulation fan according to the external airflow compensation value and output the actual external airflow value. The heating power adjustment unit is used to feedforward correct the heating power setpoint based on the actual external airflow value and adjust the heater power, outputting the actual heating power and external airflow temperature parameters. The external state output unit is used to generate an external airflow state signal based on the actual external airflow value, the actual heating power, and the external airflow temperature parameters.

8. The differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven according to claim 7, characterized in that, The steps for the internal state analysis unit to analyze the external air volume compensation value and heating power compensation value include: Extract the actual air volume value, actual pulse frequency, and internal airflow state parameters from the internal air supply status signal; Read the external parameter adjustment amount contained in the initial cooperative control command; Using the actual air volume value and actual pulse frequency as input, calculate the real-time occupancy rate of the internal loop on the total airflow energy; The real-time occupancy rate is compared with the preset target occupancy rate in the external parameter adjustment amount to obtain the occupancy rate deviation; The external air volume compensation value is calculated based on the occupancy rate deviation, and the compensation direction is to reduce the external air volume in order to release air kinetic energy for use by the internal circuit. The heating power compensation value is calculated based on the external air volume compensation value and the real-time occupancy rate to compensate for the possible decrease in external airflow temperature due to the reduction in external air volume. The external air volume compensation value and the heating power compensation value are encapsulated into the external adjustment command and output to the external air volume adjustment unit and the heating power adjustment unit.

9. The differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven according to claim 1, characterized in that, The fresh air supply and heat recovery module includes an external status analysis unit, a waste gas heat recovery unit, a fresh air preheating unit, a fresh air distribution and adjustment unit, and a fresh air feedback output unit. The external status analysis unit is used to analyze the fresh air distribution ratio command based on the external air supply status signal and output a fresh air adjustment command. The waste gas heat recovery unit is used to recover the waste heat from the exhaust gas emitted from the drying furnace and output a recoverable heat value. The fresh air preheating unit is used to preheat the fresh air based on the recoverable heat value and output the temperature and flow parameters of the preheated air. The fresh air distribution and adjustment unit is used to adjust the opening of the fresh air valves leading to the internal and external loops based on the temperature and flow parameters of the preheated air and the fresh air distribution ratio command, and output the actual fresh air distribution flow rate. The fresh air feedback output unit is used to generate a fresh air status feedback signal based on the actual fresh air distribution flow rate.

10. A differentiated air circulation system for the interior and exterior of a horizontally mounted painting and drying oven according to claim 9, characterized in that, The steps for the fresh air feedback output unit to generate a fresh air status feedback signal include: Receive the actual fresh air distribution flow rate output by the fresh air distribution and adjustment unit, wherein the actual fresh air distribution flow rate includes the actual fresh air flow rate entering the internal loop and the actual fresh air flow rate entering the external loop; The actual fresh air flow entering the internal loop is compared with the preset fresh air demand value of the internal loop to calculate the internal fresh air satisfaction rate. The actual fresh air flow entering the external loop is compared with the preset fresh air demand value of the external loop to calculate the external fresh air satisfaction rate. The recoverable heat value is compared with the preset maximum recoverable heat value to calculate the heat recovery efficiency; The temperature of the preheated air is compared with the preset preheating target temperature to calculate the preheating quality index. The internal fresh air satisfaction rate, external fresh air satisfaction rate, heat recovery efficiency, and preheating quality indicators are encapsulated into the fresh air status feedback signal and output to the data fusion and preprocessing unit of the multi-source sensing and edge computing module.

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