Spraying system capable of intelligently adjusting wind balance of whole line

Abstract

The invention discloses a spraying system capable of intelligently adjusting air balance of a whole line. The spraying system comprises an air supply and exhaust control unit, a multi-dimensional sensor unit and a control unit. The air supply and exhaust control unit comprises a plurality of air supply and exhaust systems which are applied to a feeding and discharging area, a heating chamber, a manual and automatic dust removal area, a slitting area, a UV curing area and a spraying room respectively and structurally comprises a high-pressure fan, an air supplement fan, an environment air supply box, a proportional valve, a circulating fan and a waste discharge fan, and it is ensured that the air volume and the pressure difference of all the areas are controllable. The multi-dimensional sensor unit is used for collecting air volume, pressure difference and VOC concentration data of each area. The control unit comprises a PLC (Programmable Logic Controller), a frequency converter group and an industrial personal computer, and is used for executing a PID (Proportion Integration Differentiation) control strategy and adjusting the rotating speed of a fan and the opening degree of a proportional valve based on sensor data through a wind balance control algorithm and a VOC concentration control algorithm so as to realize the stable control on the wind balance of the whole line and the VOC concentration of the spraying room. According to the system, various air supply and exhaust mechanisms and intelligent control algorithms are integrated, and the environment control precision and efficiency in the spraying process can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of spraying devices, and in particular to a spraying system capable of intelligently adjusting the wind balance of an entire line. Background Art

[0002] Existing spraying production lines usually rely on a variety of air supply and exhaust systems to control the air flow in different areas, including loading and unloading areas, ovens, dust removal areas, UV curing areas, and spray booths. These air supply and exhaust systems adjust the air volume and pressure difference through devices such as fans and proportional valves to meet the requirements of spraying operations for cleanliness, temperature, and airflow stability. At the same time, in order to monitor environmental parameters, the system is usually equipped with a pressure difference sensor, air volume sensor, and volatile organic compound (VOC) concentration sensor to provide relevant data to assist in adjustment.

[0003] However, in the existing technology, due to the lack of intelligent unified control mechanism, the operation of air supply and exhaust systems in various areas is often independent of each other, and it is impossible to coordinate the dynamic changes of air volume and pressure difference in real time. In addition, the VOC concentration in the spray room fluctuates greatly, and the existing manual or single control method is difficult to achieve efficient and stable control, which affects the spraying quality and the safety of the working environment.

[0004] Therefore, it is necessary to develop a spraying system that can intelligently adjust the wind balance of the entire line. Summary of the invention

[0005] The present application provides a spraying system that can intelligently adjust the wind balance of the entire line to improve the environmental control accuracy and efficiency of the spraying process.

[0006] The present application provides a spraying system capable of intelligently adjusting the wind balance of the entire line, comprising: The air supply and exhaust control unit comprises a plurality of independent air supply and exhaust systems, wherein the air supply and exhaust systems comprise an environmental air supply and exhaust system, an oven circulating air system, a manual dust removal air supply and exhaust system, an automatic dust removal air supply and exhaust system, a UV curing air supply and exhaust system, and a spray booth wind balance system; wherein the environmental air supply and exhaust system is arranged in the loading and unloading area, and comprises a high-pressure fan, an environmental air supply box, and a first proportional valve arranged on the environmental air supply box; the oven circulating air system is arranged in the heating chamber, and comprises a built-in fan and a second proportional valve arranged on the heating chamber; the manual dust removal air supply and exhaust system comprises a first air supply fan and a first exhaust fan; the automatic dust removal air supply and exhaust system comprises a second air supply fan and a second exhaust fan; the UV curing air supply and exhaust system comprises a third air supply fan and a third exhaust fan; the spray booth wind balance system comprises a fresh air system, a circulating air system, and an exhaust fan, wherein the fresh air system comprises a fresh air fan, the circulating air system comprises a circulating fan, and the circulating air system and the exhaust fan share an air outlet pipe; The multi-dimensional sensor unit includes a first differential pressure sensor disposed in the loading and unloading area, used to detect the pressure difference between the loading and unloading area and the external environment; a first air volume sensor and a second differential pressure sensor disposed in the heating chamber, used to detect the air volume in the heating chamber and the pressure difference between the loading and unloading area and the heating chamber, respectively; a second air volume sensor and a third differential pressure sensor disposed in the manual dust removal air supply and exhaust system; a third air volume sensor and a fourth differential pressure sensor disposed in the automatic dust removal air supply and exhaust system; a fourth air volume sensor and a fifth differential pressure sensor disposed in the UV curing air supply and exhaust system; a VOC concentration sensor, a sixth differential pressure sensor, a fifth air volume sensor disposed in the spray room, and a pressure sensor disposed on the air outlet pipe; A control unit includes a PLC controller, a frequency converter group and an industrial computer, wherein the PLC controller is electrically connected to the multidimensional sensor unit for collecting sensor signals and executing preset control logic; the frequency converter group is electrically connected to each fan for adjusting the fan speed; the industrial computer is used to execute a wind balance control algorithm and a VOC concentration control algorithm, wherein the wind balance control algorithm is based on real-time data of each pressure difference sensor and air volume sensor, adopts a PID control strategy, and adjusts the output frequency and proportional valve opening of the corresponding frequency converter through the PLC controller to achieve pressure balance and set air volume between each area; the VOC concentration control algorithm is based on the real-time data of the VOC concentration sensor, combined with the pressure sensor data, and coordinately adjusts the speed of the exhaust fan, the fresh air fan and the circulation fan through the PLC controller to achieve stable control of the VOC concentration in the spray room.

[0007] Furthermore, the first proportional valve of the environmental air supply and exhaust system is provided with a minimum opening value for maintaining a positive pressure state of the loading and unloading area relative to the external environment, and the pressure difference between the loading and unloading area and the external environment is detected by the first pressure difference sensor.

[0008] Furthermore, the second proportional valve of the oven circulating air system is set as an air supply port for adjusting the pressure difference between the line oven and the environment of the loading and unloading area, and the pressure difference is detected by the second pressure difference sensor.

[0009] Furthermore, the pressure sensor on the air outlet duct is used to detect the pressure of the common duct of the circulating air system and the exhaust fan, and the detection value of the pressure sensor is used as the basis for adjusting the speed of the circulating fan.

[0010] Furthermore, the air supply and exhaust of the environmental supply and exhaust system are controlled by the high-pressure fan to form a system that approximates circulating air. The first proportional valve on the environmental air supply box is set with a minimum opening value, and the high-pressure fan is set with an initial frequency value to maintain a positive pressure state in the environment of the loading and unloading area relative to the external environment during normal operation, while ensuring that the environmental ventilation frequency of the loading and unloading area is not less than 20 times / hour, and the wind speed is between 0.2-0.5 m / s.

[0011] Furthermore, the third pressure difference sensor of the manual dust removal and exhaust system is used to monitor the pressure difference between the manual dust removal station and the loading and unloading area, and adjust the frequency of the first exhaust fan through the frequency converter of the first exhaust fan to maintain a slightly negative pressure state at the manual dust removal station.

[0012] Furthermore, the fifth differential pressure sensor of the UV curing air supply and exhaust system is used to monitor the pressure difference between the UV light curing station and the channels on both sides, and the frequency of the third exhaust fan is adjusted by the frequency converter of the third exhaust fan to maintain a slightly negative pressure state at the UV light curing station, thereby reducing the escape of cold air into the line oven.

[0013] Furthermore, the control unit is specifically used for: The first differential pressure sensor measures the pressure difference between the loading and unloading area and the external environment The second differential pressure sensor measures the pressure difference between the heating chamber and the loading and unloading area. The sixth differential pressure sensor measures the pressure difference between the spray room and the external environment ; The first air volume sensor measures the air volume in the heating chamber The fifth air volume sensor measures the real-time air volume of the spray room ; The pressure difference deviation is calculated according to the following formula 1: in, Indicates at time Area The pressure difference deviation; Indicates loading and unloading area; Indicates a heating chamber; It means spray room; Indicates area The pressure difference weight factor of Indicates area Set pressure difference; For in time The differential pressure data measured by the differential pressure sensor; According to the following formula 2, calculate the air volume deviation: in, Indicates at time Area Air volume deviation; Indicates a heating chamber; It means spray room; Indicates area The air volume weight factor; Indicates area Set air volume; For in time Air volume data measured by air volume sensor; According to the following formula 3, the first proportional valve opening is calculated : in, is the proportional control gain; is the integral control gain; is the differential control gain; It is the parameter for adjusting the amplitude of proportional valve; Adjust the parameters for the proportional valve frequency; Indicates time; According to the following formula 4, calculate the frequency of the built-in fan of the oven circulation system : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the pressure difference deviation suppression factor for fan frequency regulation; Indicates time; According to the calculated opening of the first proportional valve and frequency , the output frequency of the corresponding inverter and the opening of the proportional valve are adjusted through the PLC controller.

[0014] Furthermore, the control unit is also used for: According to the following formula 5, calculate the second proportional valve opening : in, is the proportional control gain; is the integral control gain; is the differential control gain; It is the parameter for adjusting the amplitude of proportional valve; Adjust the parameters for the proportional valve frequency; Indicates time; According to the following formula 6, calculate the frequency of the fresh air fan : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the pressure difference deviation suppression factor for fan frequency regulation; Indicates time; According to the calculated opening of the second proportional valve and frequency , the output frequency of the corresponding inverter and the opening of the proportional valve are adjusted through the PLC controller.

[0015] Furthermore, the control unit is specifically used for: Use VOC concentration sensor to obtain VOC concentration in the spray booth ; Use pressure sensor to obtain the pressure in the spray booth outlet pipe ; The collected data is filtered and the filtered VOC concentration is calculated according to the following formulas 7 and 8. and the filtered outlet pressure : in, is the filter window size; According to the following formula 9, calculate the VOC concentration deviation : in, It is the pre-set target VOC concentration of the spray booth; is the weight factor for VOC concentration control; According to the following formula 10, calculate the pressure deviation : in, is the target air outlet pressure; is the pressure control weight factor; According to the following formula 11, calculate the exhaust fan frequency : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the current time; 0 in the definite integral represents the time when the fan starts working; According to the following formula 12, calculate the fresh air fan frequency : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the current time; 0 in the definite integral represents the time when the fan starts working; According to the following formula 13, calculate the circulation fan frequency : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the current time; 0 in the definite integral represents the time when the fan starts working; is the dynamic adjustment factor; is the magnification factor; is the index inhibition factor; Based on the calculated exhaust fan frequency , Fresh air fan frequency And the circulation fan frequency The speed of the exhaust fan, fresh air fan and circulating fan is adjusted through the PLC controller to achieve stable control of the VOC concentration in the spray room.

[0016] This application has the following beneficial technical effects: (1) By integrating multi-dimensional sensor units and wind balance control algorithms, the pressure difference and air volume data of each area are collected in real time, and the fan speed and proportional valve opening are adjusted in combination with the PID control strategy, so that the pressure balance and precise control of the set air volume in the loading and unloading area, heating chamber, spray room and other areas can be achieved, thereby improving the stability and uniformity of the spraying process. (2) Through the real-time data input of the VOC concentration sensor and pressure sensor, combined with the PLC controller and VOC concentration control algorithm, the speed of the exhaust fan, fresh air fan and circulation fan can be dynamically adjusted to ensure that the VOC concentration in the spray room is maintained within a safe and stable range, effectively improving the safety and environmental protection of the working environment. (3) The intelligent control system is used to dynamically adjust the operating status of each air supply and exhaust system. By reasonably allocating air volume and adjusting fan speed, energy waste caused by excessive air supply and exhaust can be avoided, thereby improving the overall energy efficiency of the spraying system. (4) Through the modular design of the air supply and exhaust control unit, each independent system (such as the environmental air supply and exhaust system, UV curing air supply and exhaust system, etc.) can work in coordination. Combined with the intelligent control of PLC and industrial computer, unified management of the wind balance of the entire line can be achieved, thereby improving the operating efficiency and reliability of the entire spraying system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a spraying system that can intelligently adjust the wind balance of the entire line provided in the first embodiment of the present application. DETAILED DESCRIPTION

[0018] Many specific details are described in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present application, so the present application is not limited by the specific implementation disclosed below.

[0019] The first embodiment of the present application provides a spraying system that can intelligently adjust the wind balance of the entire line. Figure 1 , which is a schematic diagram of the first embodiment of the present application. Figure 1 The first embodiment of the present application provides a spraying system that can intelligently adjust the wind balance of the entire line and is described in detail.

[0020] The spraying system capable of intelligently adjusting the wind balance of the entire line includes a supply and exhaust air control unit 101 , a multi-dimensional sensor unit 102 and a control unit 103 .

[0021] The air supply and exhaust control unit 101 includes a plurality of independent air supply and exhaust systems, wherein the air supply and exhaust systems include an environmental air supply and exhaust system, an oven circulating air system, a manual dust removal air supply and exhaust system, an automatic dust removal air supply and exhaust system, a UV curing air supply and exhaust system, and a spray booth wind balance system; wherein the environmental air supply and exhaust system is arranged in the loading and unloading area, and includes a high-pressure fan, an environmental air supply box, and a first proportional valve arranged on the environmental air supply box; the oven circulating air system is arranged in the heating chamber, and includes a built-in fan and a second proportional valve arranged on the heating chamber; the manual dust removal air supply and exhaust system includes a first air supply fan and a first exhaust fan; the automatic dust removal air supply and exhaust system includes a second air supply fan and a second exhaust fan; the UV curing air supply and exhaust system includes a third air supply fan and a third exhaust fan; the spray booth wind balance system includes a fresh air system, a circulating air system, and an exhaust fan, wherein the fresh air system includes a fresh air fan, the circulating air system includes a circulating fan, and the circulating air system and the exhaust fan share an air outlet pipe.

[0022] As an important process of the spraying production line, the slitting area adopts an independent design scheme for its air supply and exhaust system. This area is equipped with a dedicated air supply and exhaust device, which can effectively collect the debris and dust generated during the slitting process by accurately controlling the direction and speed of the airflow. The system sets up a local air supply device at the slitting station to ensure that the cutting area has a stable airflow field, and at the same time, a dust collection device is arranged around the station to prevent dust from spreading.

[0023] The air supply fan plays an important role in air flow balance in the whole system. They are mainly installed in areas where pressure balance needs to be precisely controlled, such as the transition section between the spray booth and the adjacent area, the inlet and outlet of the oven, etc. The air supply fan operates through frequency conversion control, and can accurately adjust the air supply volume according to the real-time feedback of the pressure difference sensor to help maintain the pressure gradient between the functional areas.

[0024] The air supply and exhaust control unit 101 in the spraying system that intelligently adjusts the wind balance of the entire line is designed to achieve wind balance control of the entire spraying production line. The unit ensures that the environmental parameters of each workstation of the production line are always maintained in the best state by rationally arranging multiple independent air supply and exhaust systems, thereby improving the spraying quality and reducing energy consumption.

[0025] The air supply and exhaust control unit 101 includes six air supply and exhaust systems that work in coordination with each other. The environmental air supply and exhaust system is arranged in the loading and unloading area, and is mainly driven by a high-pressure fan to circulate the air flow, and the treated clean air is delivered to the working area through the environmental air supply box. The first proportional valve arranged on the environmental air supply box can automatically adjust the air supply volume according to the environmental pressure requirement. The system controls the balance between the supply and exhaust air, and ensures that the ventilation frequency is not less than 20 times / hour, so that the loading and unloading area always maintains a positive pressure state relative to the external environment, thereby effectively preventing the intrusion of external pollutants. The supply air is delivered by the air outlet located at the top, and the wind speed can be precisely adjusted within the range of 0.2-0.5 m / s, and the exhaust air is collected by the return air column arranged at the bottom.

[0026] The oven circulation air system is installed in the heating chamber, and uses a built-in fan to realize hot air circulation. The second proportional valve set on the top of the heating chamber is used as an air supply port to adjust the amount of fresh air introduced according to actual needs. The system ensures that a constant micro-positive pressure state is maintained between the line oven and the loading and unloading area environment through precise control, which not only ensures the stability of the oven temperature, but also prevents excessive heat loss.

[0027] The manual dust removal air supply and exhaust system is equipped with a first air supply fan and a first exhaust fan, which work together to maintain the cleanliness of the workstation. The system controls the balance of air supply and exhaust to form a stable micro-negative pressure state between the manual dust removal workstation and the loading and unloading area environment, effectively preventing the dust generated by the dust removal operation from spreading to other areas. The system keeps the air exchange rate of the workstation at more than 20 times / hour to ensure that the working environment is continuously clean.

[0028] The structure of the automatic dust removal air supply and exhaust system is similar to that of the manual dust removal system, but it is optimized for the characteristics of automated operations. The system consists of a second air supply fan and a second exhaust fan. By precisely controlling the coordination of the two, while ensuring the dust removal effect, the automatic dust removal station and the channels on both sides always maintain an appropriate negative pressure difference to avoid dust pollution.

[0029] The UV curing air supply and exhaust system adopts a combination of the third air supply fan and the third exhaust fan, focusing on the temperature control requirements during the UV curing process. The system effectively reduces the infiltration of cold air into the line oven by maintaining a slight negative pressure state between the workstation and the channels on both sides, thereby reducing the fluctuation range of the oven temperature and ensuring the stability of the curing effect.

[0030] The spray booth wind balance system adopts an innovative design that uses a fresh air system, a circulating air system and an exhaust fan to work together. The fresh air system is driven by a fresh air fan to provide fresh air to the spray booth; the circulating air system uses the circulating fan to circulate the air inside the spray booth. It is particularly noteworthy that the circulating air system and the exhaust fan share an outlet pipe. This design not only saves pipeline space, but also facilitates unified management of exhaust. The exhaust fan is set with a minimum operating frequency limit, and can automatically adjust the exhaust volume according to changes in VOC concentration, ensuring the air quality inside the spray booth while achieving efficient use of energy.

[0031] Each air supply and exhaust system forms an organic whole through the pipeline system and operates in coordination under the unified dispatch of the control system. This multi-system coordinated design not only ensures that the independent environmental needs of each workstation are met, but also achieves airflow balance for the entire production line, effectively improving the spraying quality and reducing energy consumption. The operating parameters of each system can be independently adjusted according to production needs, with extremely high flexibility and adaptability.

[0032] Furthermore, the first proportional valve of the environmental air supply and exhaust system is provided with a minimum opening value for maintaining a positive pressure state of the loading and unloading area relative to the external environment, and the pressure difference between the loading and unloading area and the external environment is detected by the first pressure difference sensor.

[0033] This embodiment adopts a proportional valve control scheme in the environmental air supply and exhaust system, and realizes precise adjustment of the environmental pressure in the loading and unloading area by a first proportional valve arranged on the environmental air supply box. The proportional valve adopts the structure of an electric regulating valve, has the characteristics of rapid response and precise positioning, and can realize continuous adjustable opening.

[0034] The minimum opening value of the first proportional valve is a key parameter to ensure the positive pressure state of the loading and unloading area. The setting of this minimum opening value is based on the system's engineering experience and actual operation requirements, and is usually set within 10% to 15% of the full stroke of the valve. This minimum opening ensures that even when the system load is low, sufficient air supply can be maintained to maintain the positive pressure state of the loading and unloading area relative to the external environment. The drive device of the first proportional valve adopts a high-precision stepper motor and is equipped with a self-locking mechanism, which can accurately position the valve at any opening position.

[0035] In order to accurately monitor the pressure difference between the loading and unloading area and the external environment, a high-precision first differential pressure sensor is installed in the loading and unloading area. The sensor adopts the principle of capacitive differential pressure detection. One pressure sampling port is arranged in the central area of ​​the loading and unloading area, and the other sampling port extends to the external environment. The pressure state of the area is monitored by measuring the pressure difference between the two points. The differential pressure sensor has a range of -50Pa to +50Pa, and the measurement accuracy is better than ±1%, which can keenly capture tiny pressure changes.

[0036] The pressure difference signal detected by the first pressure difference sensor is transmitted to the PLC controller through a shielded cable. When the detected pressure difference value is lower than the set positive pressure value, the control system will first increase the air supply by adjusting the frequency of the high-pressure fan. If the high-pressure fan frequency has reached the maximum value and the pressure difference is still insufficient, the system will appropriately increase the opening of the first proportional valve to increase the air supply. Conversely, when the detected pressure difference is too large, the system will reduce the opening of the proportional valve accordingly, but always ensure that the opening is not lower than the preset minimum value.

[0037] This control strategy based on the minimum opening value, combined with an accurate pressure difference detection mechanism, can effectively prevent external pollutants from penetrating into the loading and unloading area through the gaps, while avoiding energy waste caused by excessive positive pressure. In practical applications, this control scheme has shown good stability and reliability, and can always maintain an ideal pressure balance state even when the external environmental pressure fluctuates greatly.

[0038] Furthermore, the second proportional valve of the oven circulating air system is set as an air supply port for adjusting the pressure difference between the line oven and the environment of the loading and unloading area, and the pressure difference is detected by the second pressure difference sensor.

[0039] The oven circulating air system of this embodiment is provided with a second proportional valve as an air supply port at the top of the heating chamber. This design fully considers the temperature field distribution and pressure balance requirements during the operation of the oven. The second proportional valve is made of high temperature resistant alloy material, has good heat resistance and structural stability, and can operate reliably for a long time in the high temperature environment of the oven.

[0040] The air supply function of the second proportional valve is mainly used to control the pressure balance between the linear oven and the loading and unloading area. Since the oven will produce a rising effect of hot air flow during operation, it is easy to cause the formation of local negative pressure. If fresh air is not replenished in time, untreated air may be inhaled from the loading and unloading area, affecting the uniformity of the temperature field in the oven. The second proportional valve can effectively suppress this adverse effect by accurately controlling the air supply volume.

[0041] To achieve precise pressure control, a second differential pressure sensor is installed between the heating chamber and the loading and unloading area. The sensor adopts a double diaphragm differential pressure structure and has high temperature resistance. One pressure port is located inside the heating chamber, and the other pressure port extends to the loading and unloading area. The signal acquisition circuit of the sensor adopts a temperature compensation design to ensure stable measurement accuracy under different temperature conditions.

[0042] The pressure balance control of the oven circulation air system adopts a closed-loop feedback mechanism. When the second pressure difference sensor detects that the pressure difference between the linear oven and the loading and unloading area deviates from the set value, the control system will automatically adjust the opening of the second proportional valve. If the pressure inside the oven is detected to be lower than the target value, the system will appropriately increase the opening of the second proportional valve to increase the air supply; conversely, if the pressure is too high, the valve opening will be reduced to reduce the air supply. This dynamic adjustment ensures that a stable micro-positive pressure state is always maintained inside the oven.

[0043] The control accuracy of the second proportional valve directly affects the working performance of the oven. To this end, the proportional valve is driven by a high-precision stepper motor and cooperates with a dedicated valve positioner to achieve an opening adjustment accuracy of 0.1 degrees. The valve body adopts a V-shaped adjustment structure, which has good flow characteristics within a small opening range, making it easy to achieve accurate air supply volume adjustment.

[0044] In actual application, the second proportional valve works in conjunction with the built-in fan. The built-in fan is responsible for maintaining the hot air circulation inside the oven, while the second proportional valve balances the pressure by adjusting the air supply volume. This coordination not only ensures the uniformity of the temperature inside the oven, but also effectively prevents excessive heat loss. When the production line is started, the system first makes the built-in fan reach the preset speed, and then gradually adjusts the opening of the second proportional valve until the ideal pressure balance state is established. During the production process, even if the oven load changes, the system can respond quickly and adjust the air supply volume in time to maintain a stable pressure balance.

[0045] Furthermore, the air supply and exhaust of the environmental supply and exhaust system are controlled by the high-pressure fan to form a system that approximates circulating air. The first proportional valve on the environmental air supply box is set with a minimum opening value, and the high-pressure fan is set with an initial frequency value to maintain a positive pressure state in the environment of the loading and unloading area relative to the external environment during normal operation, while ensuring that the environmental ventilation frequency of the loading and unloading area is not less than 20 times / hour, and the wind speed is between 0.2-0.5 m / s.

[0046] The environmental air supply and exhaust system adopts an approximate circulating air design scheme, and controls the air supply and exhaust simultaneously through a single high-pressure fan, thus simplifying the system structure and unifying the control. The high-pressure fan adopts a backward centrifugal structure, which has the characteristics of high efficiency and low noise. Its working characteristic curve is stable and easy to adjust accurately.

[0047] The air supply part of the system delivers the processed air to the top of the loading and unloading area through the environmental air supply box. The air supply box adopts a baffle structure design, and a guide device is set inside to make the air flow evenly diffuse and ensure the uniform distribution of air flow in the air supply area. The air supply port adopts a grille layout, and each grille can be adjusted independently to facilitate the fine-tuning of the wind speed on site. The first proportional valve set on the environmental air supply box adopts an electric butterfly valve structure, and its minimum opening value is usually set at about 12% of the full stroke of the valve. This value is the best setting point verified by a large number of practices, which can ensure the necessary air supply volume while avoiding energy waste.

[0048] The initial frequency value of the high-pressure fan is an important parameter for the stable operation of the system. The determination of this frequency value requires comprehensive consideration of factors such as the spatial volume of the loading and unloading area, the target ventilation times and the required wind speed. Through precise calculation, the system sets the initial operating frequency of the high-pressure fan at 35Hz, which can generate sufficient air volume while leaving room for upward adjustment to cope with changes in working conditions. The variable frequency control of the fan adopts vector control, which can achieve smooth adjustment of the speed and avoid the impact of frequent start and stop on the equipment.

[0049] To ensure the cleanliness of the loading and unloading area, the system strictly controls the ventilation frequency to no less than 20 times / hour. This indicator is determined by the ratio of the actual air supply volume and the volume of the loading and unloading area obtained by real-time monitoring of the air volume sensor. The system will continue to calculate the current ventilation frequency during operation. Once it is found to be lower than the set value, the controller will automatically increase the fan frequency or adjust the proportional valve opening to increase the air volume.

[0050] Wind speed control is another key parameter. The system monitors the wind speed in the working area in real time through wind speed sensors placed at key locations. The control system adjusts the operating frequency of the high-pressure fan to ensure that the wind speed in the working area is always maintained within the range of 0.2-0.5 m / s. This wind speed range can effectively prevent dust deposition without interfering with the workpiece. The wind speed sensor adopts a thermal sensitive design with fast response characteristics, which can capture changes in wind speed in a timely manner.

[0051] The exhaust part of the near-circulating air system collects air through the return air column located at the bottom. The return air column adopts a multi-point suction design and a filter device is set at the bottom to effectively block larger particles. The cross-sectional area of ​​the return air duct is carefully designed to ensure that the exhaust resistance is minimized while maintaining an appropriate wind speed to prevent particle deposition. Since the supply and exhaust air are controlled by the same high-pressure fan, the system has good self-balancing characteristics, which can effectively reduce the impact of external interference.

[0052] Through this design, the system not only achieves precise control of the loading and unloading area environment, but also significantly reduces energy consumption. In actual operation, the system shows excellent stability and reliability. Even when the working conditions change, the operating parameters can be quickly adjusted to maintain various indicators within the ideal range. At the same time, compared with the traditional independent supply and exhaust air system, this nearly circulating air solution has the advantages of low investment cost and simple maintenance, and is an economical and efficient solution.

[0053] The multidimensional sensor unit 102 includes a first differential pressure sensor arranged in the loading and unloading area, which is used to detect the pressure difference between the loading and unloading area and the external environment; a first air volume sensor and a second differential pressure sensor arranged in the heating chamber, which are respectively used to detect the air volume in the heating chamber and the pressure difference between it and the loading and unloading area; a second air volume sensor and a third differential pressure sensor arranged in the manual dust removal air supply and exhaust system; a third air volume sensor and a fourth differential pressure sensor arranged in the automatic dust removal air supply and exhaust system; a fourth air volume sensor and a fifth differential pressure sensor arranged in the UV curing air supply and exhaust system; a VOC concentration sensor, a sixth differential pressure sensor, a fifth air volume sensor arranged in the spray room, and a pressure sensor arranged on the air outlet pipe.

[0054] The spraying system uses a multi-dimensional sensor unit 102 to achieve real-time monitoring of key areas of the entire production line. The sensor unit builds a comprehensive data acquisition network through reasonable layout, providing a reliable data basis for the intelligent control of the system.

[0055] In the loading and unloading area, a high-precision first differential pressure sensor is set up to monitor the pressure difference between the area and the external environment in real time. The sensor adopts a differential pressure design, with one end connected to the pressure port of the loading and unloading area and the other end connected to the pressure port of the external environment, continuously monitoring the pressure difference between the two environments. Through the real-time feedback of the differential pressure data, the system can timely adjust the operating frequency of the high-pressure fan and the opening of the first proportional valve to ensure that the loading and unloading area is always maintained in an ideal positive pressure state, effectively blocking the invasion of external pollutants.

[0056] The heating chamber area is equipped with two sensors with different functions, namely the first air volume sensor and the second differential pressure sensor. The first air volume sensor uses thermal flow detection technology and is installed on the main air duct of the heating chamber to accurately measure the air volume flowing through the area. The second differential pressure sensor is responsible for monitoring the pressure difference between the heating chamber and the loading and unloading area, providing data support for the pressure balance control of the oven's circulating air system. The coordinated use of these two sensors ensures that the heating chamber obtains sufficient ventilation times and maintains an appropriate pressure gradient with adjacent areas.

[0057] In the manual dust removal air supply and exhaust system, the second air volume sensor and the third pressure difference sensor work together. The second air volume sensor is installed on the air supply duct to monitor the air volume entering the dust removal station in real time to ensure that the station maintains sufficient ventilation times. The third pressure difference sensor monitors the pressure difference between the manual dust removal station and the loading and unloading area. Its data is directly used to adjust the operating parameters of the first exhaust fan to maintain the station in a stable micro-negative pressure state to prevent dust diffusion.

[0058] The automatic dust removal air supply and exhaust system uses a combination of a third air volume sensor and a fourth pressure difference sensor. The third air volume sensor also uses the principle of thermal flow detection, and the installation position is optimized to avoid the influence of dust on the sensor. The fourth pressure difference sensor monitors the pressure difference between the automatic dust removal station and the channels on both sides. Its signal is used to control the operation of the second exhaust fan to ensure that the dust generated during the automatic dust removal process is effectively collected.

[0059] The fourth air volume sensor and the fifth differential pressure sensor equipped in the UV curing air supply and exhaust system are resistant to high temperatures. The fourth air volume sensor monitors the ventilation volume of the UV curing station in real time, and the fifth differential pressure sensor monitors the pressure difference between the station and the channels on both sides. The data of these two sensors provide a basis for the coordinated control of the third air supply fan and the third exhaust fan, which not only ensures sufficient ventilation and cooling effects, but also prevents cold air from interfering with the oven temperature field.

[0060] Several different types of sensors are installed in the spray booth area to form a comprehensive monitoring network. The VOC concentration sensor uses photoionization detection technology to accurately measure the concentration of volatile organic compounds in the spray booth. The sixth differential pressure sensor monitors the pressure difference between the spray booth and adjacent areas, and the fifth air volume sensor monitors the ventilation volume of the spray booth. These sensors are linked with the pressure sensor installed on the air outlet pipe to provide data support for VOC control and pressure balance in the spray booth. The pressure sensor on the air outlet pipe pays special attention to the pressure changes in the shared pipe section of the circulating air system and the exhaust fan, and its data directly affects the speed adjustment of the circulating fan.

[0061] All sensors are designed in industrial grade, with good dust and corrosion resistance, ensuring long-term stable operation in harsh industrial environments. The installation position of the sensor is carefully designed to ensure measurement accuracy and facilitate maintenance and repair. Each sensor is equipped with an independent signal conditioning circuit to convert the analog signal into a standard 4-20mA current signal, which is transmitted to the PLC controller through a shielded cable, effectively avoiding electromagnetic interference in the industrial field.

[0062] Furthermore, the pressure sensor on the air outlet duct is used to detect the pressure of the common duct of the circulating air system and the exhaust fan, and the detection value of the pressure sensor is used as the basis for adjusting the speed of the circulating fan.

[0063] In this embodiment, a special pressure sensor is provided on the common air outlet duct of the circulating air system and the exhaust fan to realize accurate monitoring of the pressure in the air duct and intelligent adjustment of the fan speed. The pressure sensor adopts diffused silicon pressure sensitive element, which has the characteristics of fast response and high-precision measurement, and can accurately capture the slight changes of the pressure in the air duct.

[0064] The air outlet duct adopts a circular cross-section, and its diameter is optimized through fluid mechanics calculations, which ensures sufficient ventilation and avoids excessive pressure loss. At the installation position of the pressure sensor, a special pressure measuring hole is opened on the duct wall and equipped with a dust-proof filter to ensure the accuracy of the measurement. The location of the pressure measuring hole is selected in the straight pipe section where the airflow is relatively stable, avoiding areas that are prone to turbulence such as elbows and diameter changes.

[0065] The pressure sensor is installed on the pressure measuring hole using a standard flange connection method, which is reliable in sealing and easy to maintain. The sensor has a measuring range of -1000Pa to 1000Pa, and the measurement accuracy is better than 0.5%, which meets the system's requirements for pressure monitoring. In order to avoid the influence of ambient temperature on the measurement accuracy, a heat insulation layer is set on the outside of the sensor, and a temperature compensation mechanism is added to the signal processing circuit.

[0066] The data obtained from the pressure sensor is an important basis for adjusting the speed of the circulating fan. When the pressure in the shared air duct is detected to be lower than the set value, it indicates that the exhaust volume of the system may be insufficient, and the control system will appropriately increase the speed of the circulating fan. On the contrary, if the pressure exceeds the set value, the speed of the circulating fan will be reduced to avoid excessive pipe resistance. This speed adjustment method based on pressure feedback can achieve the best collaborative working state between the circulating air system and the exhaust fan.

[0067] The system uses a progressive PID control algorithm to determine the speed adjustment strategy of the circulating fan. The controller first compares the measured pressure value with the set pressure value, and then calculates the appropriate speed adjustment amount based on the pressure difference and change trend. In order to avoid damage to the fan caused by frequent speed adjustment, appropriate hysteresis intervals and change rate limits are set in the control algorithm to make the speed adjustment more stable.

[0068] In actual operation, this pressure feedback control method shows excellent adaptability. Even when the exhaust fan workload changes, the circulation fan can adjust the speed in time to maintain the stability of the pressure in the air duct. This not only improves the operating efficiency of the system, but also extends the service life of the equipment. At the same time, by avoiding unnecessary high-speed operation, it also achieves significant energy-saving effects.

[0069] Furthermore, the third pressure difference sensor of the manual dust removal and exhaust system is used to monitor the pressure difference between the manual dust removal station and the loading and unloading area, and adjust the frequency of the first exhaust fan through the frequency converter of the first exhaust fan to maintain a slightly negative pressure state at the manual dust removal station.

[0070] In this embodiment, a high-precision third differential pressure sensor is provided in the manual dust removal air supply and exhaust system to realize real-time monitoring and precise control of the pressure difference between the manual dust removal station and the loading and unloading area. The differential pressure sensor adopts a capacitive pressure sensing element with extremely high sensitivity, which can accurately detect small pressure changes and provide reliable data support for the pressure balance control of the system.

[0071] The installation position of the third differential pressure sensor has been carefully designed, with pressure points set at the manual dust removal station and the loading and unloading area. The pressure point on the manual dust removal station side is installed at the center height of the working area, avoiding areas with large airflow disturbances; the pressure point on the loading and unloading area side is selected at a representative position to ensure that the measured differential pressure data can truly reflect the pressure relationship between the two areas. The pressure-taking pipeline is made of corrosion-resistant stainless steel, and a dust removal and filtering device is installed on the pipeline to prevent dust from affecting the measurement accuracy.

[0072] The system adjusts the fan speed through the inverter of the first exhaust fan, thereby achieving precise control of the pressure state of the manual dust removal station. The inverter adopts high-performance vector control technology to achieve smooth adjustment of the fan speed. When the third differential pressure sensor detects that the pressure difference deviates from the set value, the inverter will automatically adjust the operating frequency of the first exhaust fan according to the direction and size of the deviation. To ensure the stability of control, the system sets a slow start and soft stop function in the control program of the inverter to avoid sudden changes causing impact on the system.

[0073] The micro-negative pressure state of the manual dust removal station is achieved by accurately controlling the exhaust volume of the first exhaust fan. The system sets the target negative pressure value within a reasonable range according to the space size and operation requirements of the dust removal station. When insufficient negative pressure is detected, the control system will appropriately increase the frequency of the first exhaust fan; when the negative pressure is too large, the fan frequency will be reduced. This dynamic adjustment ensures that the manual dust removal station always maintains an ideal micro-negative pressure state, which can effectively prevent dust from spreading outward without affecting the normal work of the operator.

[0074] In actual application, the system adopts an intelligent strategy to control the first exhaust fan. First, according to the characteristics of manual dust removal operation, the system will gradually increase the frequency according to the preset speed increase curve when the fan is started until the basic working frequency is reached. During normal operation, the control system will dynamically adjust the fan frequency according to the real-time feedback of the third pressure difference sensor to stabilize the pressure difference value within the set range. When there is a large pressure fluctuation, the system can respond quickly and adjust the fan speed in time to ensure that the pressure state of the dust removal station is always within the controllable range.

[0075] In order to adapt to different working conditions, the system also sets up multiple operating modes. In the standard operating mode, the system will strictly implement the preset pressure difference control strategy; in the enhanced dust removal mode, the system will appropriately increase the negative pressure value to improve the dust removal effect; in the energy-saving mode, the system will optimize the fan operating parameters and reduce energy consumption while ensuring the basic dust removal effect. This flexible control method enables the system to better meet actual production needs.

[0076] Furthermore, the fifth differential pressure sensor of the UV curing air supply and exhaust system is used to monitor the pressure difference between the UV light curing station and the channels on both sides, and the frequency of the third exhaust fan is adjusted by the frequency converter of the third exhaust fan to maintain a slightly negative pressure state at the UV light curing station, thereby reducing the escape of cold air into the line oven.

[0077] The fifth differential pressure sensor provided in the UV curing air supply and exhaust system of this embodiment adopts a high temperature resistant design and is specifically used for accurate monitoring of the differential pressure between the UV light curing station and the channels on both sides. The sensor uses a high-precision pressure sensing element with a double diaphragm structure and has excellent temperature compensation performance, and can maintain stable measurement accuracy even in the high temperature environment generated by UV curing.

[0078] The installation layout of the fifth differential pressure sensor has been specially designed. Multiple pressure points are set inside the UV light curing station. The pressure signals of these points are integrated through the current collecting device to obtain the average pressure value in the station; pressure points are also set on the two side channels to measure the reference pressure of the channel. The pressure-taking pipeline is made of high-temperature resistant Teflon material and a protective structure is set to prevent UV radiation from damaging the pipeline. The pressure measurement system is also equipped with a special gas cooling device to ensure that the temperature of the gas entering the sensor is within its working range.

[0079] The core control strategy of this system is to dynamically adjust the pressure difference through the inverter of the third exhaust fan. The inverter adopts advanced vector control technology to achieve precise adjustment of the fan speed. The system dynamically calculates the required fan speed based on the real-time feedback signal of the fifth differential pressure sensor and adjusts it through the inverter. This control method has a fast response speed and can respond to pressure fluctuations in the process in a timely manner.

[0080] In order to maintain the micro-negative pressure state of the UV light curing station, the system has designed a special pressure control algorithm. When the pressure difference between the station and the channel is detected to deviate from the target value, the control system will automatically adjust the frequency of the third exhaust fan. Increasing the frequency can enhance the exhaust effect and produce a greater negative pressure; reducing the frequency will weaken the exhaust intensity and reduce the negative pressure value. Through this continuous dynamic adjustment, it is ensured that the UV light curing station is always maintained in a suitable micro-negative pressure state.

[0081] The system pays special attention to preventing cold air from escaping to the line oven. Since the UV curing station needs continuous ventilation to exhaust the ozone generated by ultraviolet light, this process easily causes the invasion of surrounding cold air. By maintaining an appropriate micro-negative pressure state, the system can effectively control the direction of airflow to prevent cold air from entering the oven area through the workpiece inlet and outlet channels. This design not only protects the temperature field stability of the oven, but also reduces energy loss.

[0082] In actual operation, the system will automatically adjust the control parameters according to the different stages of the UV curing process. During the UV lamp startup phase, the system will appropriately increase the exhaust volume to quickly exhaust the initially generated ozone; during the stable operation phase, the system will maintain the ideal ventilation state through precise pressure difference control; when the process is switched, the system will smoothly adjust the parameters to avoid drastic pressure fluctuations. This intelligent control method not only ensures the stability of the UV curing process, but also achieves efficient use of energy.

[0083] Through this precise pressure difference control and reasonable air flow organization, the UV curing air supply and exhaust system successfully solves the temperature field protection problem in the curing process, significantly improves the curing quality of the product, and also optimizes the energy efficiency of the entire production line.

[0084] The control unit 103 includes a PLC controller, a frequency converter group and an industrial computer, wherein the PLC controller is electrically connected to the multi-dimensional sensor unit for collecting sensor signals and executing preset control logic; the frequency converter group is electrically connected to each fan for adjusting the fan speed; the industrial computer is used to execute a wind balance control algorithm and a VOC concentration control algorithm, wherein the wind balance control algorithm is based on real-time data of each pressure difference sensor and air volume sensor, adopts a PID control strategy, and adjusts the output frequency and proportional valve opening of the corresponding frequency converter through the PLC controller to achieve pressure balance and set air volume between each area; the VOC concentration control algorithm is based on the real-time data of the VOC concentration sensor, combined with the pressure sensor data, and coordinately adjusts the speed of the exhaust fan, the fresh air fan and the circulation fan through the PLC controller to achieve stable control of the VOC concentration in the spray room.

[0085] The control unit 103 adopts a three-layer architecture design of industrial computer, PLC controller and inverter group, realizing complete closed-loop control from data acquisition, algorithm processing to execution control. The control unit ensures that the wind balance of the entire spraying system is always in the optimal state through reasonable hardware configuration and advanced software algorithms.

[0086] As the host computer of the system, the industrial computer adopts industrial-grade computers, equipped with high-performance CPU and large-capacity memory, with high reliability and strong anti-interference ability. The industrial computer is installed in an independent control cabinet, equipped with dust-proof and moisture-proof sealing structure and industrial-grade cooling system to ensure stable operation in harsh industrial environments. The wind balance control algorithm and VOC concentration control algorithm are run on the industrial computer, and these two algorithms interact with the PLC controller in real time through industrial Ethernet.

[0087] The PLC controller adopts a modular design, including a main control module, a multi-channel analog input module, a digital input and output module, and a communication module. The analog input module is responsible for collecting 4-20mA standard current signals from the multi-dimensional sensor unit, including differential pressure signals, air volume signals, VOC concentration signals, etc. These signals are converted into engineering quantities after anti-interference processing and digital filtering for use by the control algorithm. The PLC controller processes these data through preset control logic and generates corresponding control instructions.

[0088] The inverter group consists of multiple industrial inverters, which are electrically connected to each fan. Each inverter is equipped with complete protection functions, including overcurrent protection, overvoltage protection, phase loss protection, etc. The inverter can accurately adjust the speed of the fan according to the control instructions issued by the PLC controller to achieve stepless adjustment of the air volume. The speed regulation range of the inverter is 20Hz to 50Hz, which meets the system's demand for air volume regulation.

[0089] The wind balance control algorithm in the industrial computer receives data from each pressure difference sensor and air volume sensor in real time, and uses the PID control strategy for calculation. The algorithm first compares the measured value with the set value, calculates the deviation value, and then obtains the control amount through PID calculation based on the size, change trend and accumulation of the deviation value. These control amounts are converted into specific execution instructions through the PLC controller to adjust the output frequency of the corresponding inverter and the opening of the proportional valve, thereby achieving pressure balance and air volume control between various areas.

[0090] The VOC concentration control algorithm is mainly aimed at environmental control in the spray room area. The algorithm is based on the real-time data of the VOC concentration sensor, combined with the pressure sensor data of the air outlet duct, and determines the optimal speed combination of the exhaust fan, fresh air fan and circulation fan through a complex calculation process. When it is detected that the VOC concentration exceeds the set threshold, the algorithm will give priority to increasing the speed of the exhaust fan to strengthen the exhaust; at the same time, in order to maintain the negative pressure state of the spray room, the algorithm will adjust the speed of the fresh air fan accordingly; and the speed of the circulation fan is adjusted according to the pressure condition of the air outlet duct to ensure the airflow balance of the entire system.

[0091] The control unit adopts a hierarchical control strategy to realize the intelligent operation of the system. The industrial computer is responsible for complex algorithm calculations and decision-making, the PLC controller is responsible for executing specific control logic and data acquisition, and the inverter group is responsible for executing the final control action. This hierarchical design not only ensures the real-time and reliability of the system, but also realizes the intelligent and precise control.

[0092] When the system starts, the control unit first performs a self-check to confirm that all hardware modules are working properly. Then, the data from each sensor begins to be collected and processed by digital filtering, and the control algorithm starts to run. During the operation of the system, the control unit continuously monitors the changes in various parameters and adjusts the control strategy in time to ensure that the entire spraying system is always maintained in the best state. When an abnormal situation occurs, the control unit will immediately take corresponding protective measures to ensure system safety.

[0093] Furthermore, the control unit is specifically used for: The first differential pressure sensor measures the pressure difference between the loading and unloading area and the external environment The second differential pressure sensor measures the pressure difference between the heating chamber and the loading and unloading area. The sixth differential pressure sensor measures the pressure difference between the spray room and the external environment ; The first air volume sensor measures the air volume in the heating chamber The fifth air volume sensor measures the real-time air volume of the spray room ; The pressure difference deviation is calculated according to the following formula 1: in, Indicates at time Area The pressure difference deviation; Indicates loading and unloading area; Indicates a heating chamber; Indicates spray booth; area It can be a loading and unloading area, a heating room or a spray booth; Indicates area The pressure difference weight factor is calculated based on experimental data or directly set based on expert knowledge, and the recommended value is 0.5.

[0094] Indicates area The set pressure difference is a target pressure difference value predefined according to the process requirements and system design objectives of each area, and is usually obtained through empirical data and actual process tests. For example, for the loading / unloading area, it is necessary to maintain a positive pressure relative to the outside world to prevent pollutants from entering, and the set pressure difference may be between 20 and 50Pa. For the heating room (oven), it is usually necessary to maintain a slightly positive pressure with the loading / unloading area to ensure a stable flow of hot air, and the set pressure difference is generally 10 to 30 Pa. The spray booth usually maintains a negative pressure relative to the outside world to prevent the leakage of volatile organic compounds (VOCs), and the set pressure difference is generally -3 to 0 Pa.

[0095] These set pressure differential values ​​can be confirmed by simulating the relevant process environment or debugging in actual operation. Changes in external air pressure and limitations of equipment capacity may also have a certain impact on the adjustment of the set value. The set value can be fine-tuned according to the actual usage scenario and environmental conditions to ensure that the operation of the system can meet the comprehensive requirements of safety, process stability and energy saving.

[0096] For in time Differential pressure sensor in the area Measured differential pressure data; According to the following formula 2, calculate the air volume deviation: in, Indicates at time Area Air volume deviation; Indicates a heating chamber; It means spray room; Indicates area The air volume weight factor is obtained based on experimental data or directly set based on expert knowledge, and the recommended value is 0.8.

[0097] Indicates area The set air volume is the target air volume value determined based on the actual needs of each area and the system design goals. It is usually determined comprehensively through the following aspects: First, according to the use and process requirements of the area, the air volume needs to be set to meet the ventilation and air exchange needs of each area. For example, the loading and unloading area needs sufficient air volume to maintain positive pressure to prevent external pollutants from entering; the heating room needs a constant air volume to ensure the uniform distribution of hot air; the spray room needs sufficient air volume to exhaust volatile organic compounds (VOC) to ensure the safety of the working environment.

[0098] Secondly, the air volume setting also depends on the size of the area. Generally speaking, the larger the area, the higher the air volume required. At the same time, the requirements for air renewal speed in different areas will also affect the set air volume. For example, the spray room usually requires a higher ventilation speed to quickly remove harmful gases, while the loading and unloading area may only require a lower ventilation speed to maintain pressure balance.

[0099] In addition, the air volume is set based on industry standards and the actual capacity of the equipment. For example, the air volume of the spray booth needs to meet the VOC emission standards in environmental regulations and cannot exceed the maximum output capacity of the fan to ensure stable operation of the equipment.

[0100] By combining the above factors, the set air volume is generally determined by experimental data, experience and actual test results. 4500 m can be used 3 / h, spray room set air volume 24000 m can be used 3 / h.

[0101] For in time Air flow sensor in area Measured air volume data, According to the following formula 3, the first proportional valve opening is calculated : in, is the proportional control gain, the recommended value is 1.0; is the integral control gain, the recommended value is 0.1; is the differential control gain, the recommended value is 0.01; It is the proportional valve amplitude adjustment parameter, the recommended value is 0.05; It is the frequency adjustment parameter of the proportional valve, and the recommended value is 0.1; Indicates time; According to the following formula 4, calculate the frequency of the built-in fan of the oven circulation system : in, is the proportional control gain, the recommended value is 1.1; is the integral control gain, the recommended value is 0.2; is the differential control gain, the recommended value is 0.05; is the pressure difference deviation suppression factor for fan frequency regulation, with a recommended value of 0.01; Indicates time; According to the calculated opening of the first proportional valve and frequency , the output frequency of the corresponding inverter and the opening of the proportional valve are adjusted through the PLC controller.

[0102] Furthermore, the control unit is also used for: According to the following formula 5, calculate the second proportional valve opening : in, is the proportional control gain, the recommended value is 2.1; is the integral control gain, the recommended value is 0.6; is the differential control gain, the recommended value is 0.01; It is the proportional valve amplitude adjustment parameter, the recommended value is 0.05; It is the frequency adjustment parameter of the proportional valve, and the recommended value is 0.1; Indicates time; According to the following formula 6, calculate the frequency of the fresh air fan : in, is the proportional control gain, the recommended value is 1.5; is the integral control gain, the recommended value is 0.3; is the differential control gain, the recommended value is 0.02; is the pressure difference deviation suppression factor for fan frequency regulation, with a recommended value of 0.01; Indicates time; According to the calculated opening of the second proportional valve and frequency , the output frequency of the corresponding inverter and the opening of the proportional valve are adjusted through the PLC controller.

[0103] Furthermore, the control unit is specifically used for: Use VOC concentration sensor to obtain VOC concentration in the spray booth ; Use pressure sensor to obtain the pressure in the spray booth outlet pipe ; The collected data is filtered and the filtered VOC concentration is calculated according to the following formulas 7 and 8. and the filtered outlet pressure : in, is the filter window size; According to the following formula 9, calculate the VOC concentration deviation : in, It is the pre-set target VOC concentration of the spray booth; is the weight factor for VOC concentration control; According to the following formula 10, calculate the pressure deviation : in, is the target air outlet pressure; is the pressure control weight factor; According to the following formula 11, calculate the exhaust fan frequency : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the current time; 0 in the definite integral represents the time when the fan starts working; According to the following formula 12, calculate the fresh air fan frequency : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the current time; 0 in the definite integral represents the time when the fan starts working; According to the following formula 13, calculate the circulation fan frequency : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the current time; 0 in the definite integral represents the time when the fan starts working; is the dynamic adjustment factor; is the magnification factor; is the index inhibition factor; Based on the calculated exhaust fan frequency , Fresh air fan frequency And the circulation fan frequency The speed of the exhaust fan, fresh air fan and circulating fan is adjusted through the PLC controller to achieve stable control of the VOC concentration in the spray room.

[0104] First, the control unit uses the VOC concentration sensor to obtain the real-time VOC concentration in the spray booth. , and obtain the real-time pressure in the air outlet duct through the pressure sensor ,in Indicates the current time. In order to improve the stability and reliability of the data, the collected data is filtered and the VOC concentration value calculation method after filtering is used. The window size It is usually determined based on the system's real-time performance and anti-interference capabilities. The recommended value is 50, which depends on the frequency and amplitude of environmental fluctuations.

[0105] Next, the VOC concentration deviation is calculated based on the filtered data. and pressure deviation The VOC concentration deviation is calculated by formula 9, where the target VOC concentration is It is a pre-set value based on process requirements and safety requirements, usually between 0.1 and 1 ppm; weighting factor for VOC concentration control Used to adjust the priority of VOC concentration in control, the recommended value is 0.8.

[0106] The pressure deviation is calculated by formula 10, where the target outlet pressure is Set according to the negative pressure demand of the spray room, generally ranging from -50 to 0 Pa; pressure control weight factor The recommended value is 1.5 to ensure that pressure deviations have a moderate impact on the control process.

[0107] Based on the calculated deviation, the control unit calculates the frequency of the exhaust fan, fresh air fan and circulation fan according to formulas 11, 12 and 13 respectively. Frequency of the exhaust fan Directly based on VOC concentration deviation , calculated using the PID control strategy, where the proportional gain The recommended value is 1.0, integral gain The recommended value is 0.2, differential gain The recommended value is 0.01.

[0108] Frequency of fresh air fan Based on the pressure deviation , using the same PID control strategy, where the proportional gain The recommended value is 1.5, integral gain The recommended value is 0.3, differential gain The recommended value is 0.02.

[0109] Frequency of circulating fan The calculation method is not only based on the pressure deviation PID control, also combined with VOC concentration deviation Nonlinear dynamic adjustment and suppression terms.

[0110] Dynamic Adjustment Factor The recommended value is 0.05, the magnification factor The recommended value is 0.1, which is used to enhance the responsiveness of VOC concentration deviation to dynamic regulation. The recommended value is 0.01, which is used to limit the excessive impact of excessive VOC concentration deviation on the frequency and ensure the stability of the adjustment process.

[0111] Finally, the control unit adjusts the speed of the exhaust fan, fresh air fan and circulation fan through the PLC controller according to the calculated fan frequency. This dynamic adjustment mechanism ensures that the VOC concentration in the spray booth is maintained within a safe range while keeping the pressure of the air outlet duct stable, thereby optimizing the working environment in the spray booth and the system operation efficiency.

[0112] Although the present application is disclosed as above in the form of a preferred embodiment, it is not intended to limit the present application. Any technical personnel in this field may make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application shall be based on the scope defined by the claims of the present application.

Claims

1. A spraying system that can intelligently adjust the wind balance of the entire line, characterized in that: include: The air supply and exhaust control unit comprises a plurality of independent air supply and exhaust systems, wherein the air supply and exhaust systems comprise an environmental air supply and exhaust system, an oven circulating air system, a manual dust removal air supply and exhaust system, an automatic dust removal air supply and exhaust system, a UV curing air supply and exhaust system, and a spray booth wind balance system; wherein the environmental air supply and exhaust system is arranged in the loading and unloading area, and comprises a high-pressure fan, an environmental air supply box, and a first proportional valve arranged on the environmental air supply box; the oven circulating air system is arranged in the heating chamber, and comprises a built-in fan and a second proportional valve arranged on the heating chamber; the manual dust removal air supply and exhaust system comprises a first air supply fan and a first exhaust fan; the automatic dust removal air supply and exhaust system comprises a second air supply fan and a second exhaust fan; the UV curing air supply and exhaust system comprises a third air supply fan and a third exhaust fan; the spray booth wind balance system comprises a fresh air system, a circulating air system, and an exhaust fan, wherein the fresh air system comprises a fresh air fan, the circulating air system comprises a circulating fan, and the circulating air system and the exhaust fan share an air outlet pipe; The multi-dimensional sensor unit includes a first differential pressure sensor disposed in the loading and unloading area, used to detect the pressure difference between the loading and unloading area and the external environment; a first air volume sensor and a second differential pressure sensor disposed in the heating chamber, used to detect the air volume in the heating chamber and the pressure difference between the loading and unloading area and the heating chamber, respectively; a second air volume sensor and a third differential pressure sensor disposed in the manual dust removal air supply and exhaust system; a third air volume sensor and a fourth differential pressure sensor disposed in the automatic dust removal air supply and exhaust system; a fourth air volume sensor and a fifth differential pressure sensor disposed in the UV curing air supply and exhaust system; a VOC concentration sensor, a sixth differential pressure sensor, a fifth air volume sensor disposed in the spray room, and a pressure sensor disposed on the air outlet pipe; A control unit includes a PLC controller, a frequency converter group and an industrial computer, wherein the PLC controller is electrically connected to the multidimensional sensor unit for collecting sensor signals and executing preset control logic; the frequency converter group is electrically connected to each fan for adjusting the fan speed; the industrial computer is used to execute a wind balance control algorithm and a VOC concentration control algorithm, wherein the wind balance control algorithm is based on real-time data of each pressure difference sensor and air volume sensor, adopts a PID control strategy, and adjusts the output frequency and proportional valve opening of the corresponding frequency converter through the PLC controller to achieve pressure balance and set air volume between each area; the VOC concentration control algorithm is based on the real-time data of the VOC concentration sensor, combined with the pressure sensor data, and coordinately adjusts the speed of the exhaust fan, the fresh air fan and the circulation fan through the PLC controller to achieve stable control of the VOC concentration in the spray room.

2. The spraying system according to claim 1, characterized in that: The first proportional valve of the environmental air supply and exhaust system is provided with a minimum opening value for maintaining a positive pressure state of the loading and unloading area relative to the external environment. The pressure difference between the loading and unloading area and the external environment is detected by the first pressure difference sensor.

3. The spraying system according to claim 1, characterized in that: The second proportional valve of the oven circulating air system is set as an air supply port, which is used to adjust the pressure difference between the line oven and the environment of the loading and unloading area, and the pressure difference is detected by the second pressure difference sensor.

4. The spraying system according to claim 1, characterized in that: The pressure sensor on the air outlet pipe is used to detect the pressure of the common air duct of the circulating air system and the exhaust fan, and the detection value of the pressure sensor is used as the basis for adjusting the speed of the circulating fan.

5. The spraying system according to claim 1, characterized in that: The air supply and exhaust of the environmental supply and exhaust system are controlled by the high-pressure fan to form a system that approximates circulating air. The first proportional valve on the environmental air supply box is set with a minimum opening value, and the high-pressure fan is set with an initial frequency value to maintain a positive pressure state in the environment of the loading and unloading area relative to the external environment during normal operation, while ensuring that the environmental ventilation frequency of the loading and unloading area is not less than 20 times / hour, and the wind speed is between 0.2-0.5 m / s.

6. The spraying system according to claim 1, characterized in that: The third pressure difference sensor of the manual dust removal and exhaust air supply system is used to monitor the pressure difference between the manual dust removal station and the loading and unloading area, and adjust the frequency of the first exhaust fan through the frequency converter of the first exhaust fan to maintain a slightly negative pressure state at the manual dust removal station.

7. The spraying system according to claim 1, characterized in that: The fifth differential pressure sensor of the UV curing air supply and exhaust system is used to monitor the pressure difference between the UV light curing station and the channels on both sides. The frequency of the third exhaust fan is adjusted by the frequency converter of the third exhaust fan to maintain a slightly negative pressure state at the UV light curing station and reduce the escape of cold air into the line oven.

8. The spraying system according to claim 1, characterized in that: The control unit is specifically used for: The first differential pressure sensor measures the pressure difference between the loading and unloading area and the external environment The second differential pressure sensor measures the pressure difference between the heating chamber and the loading and unloading area. The sixth differential pressure sensor measures the pressure difference between the spray room and the external environment ; The first air volume sensor measures the air volume in the heating chamber The fifth air volume sensor measures the real-time air volume of the spray room ; The pressure difference deviation is calculated according to the following formula 1: in, Indicates at time Area The pressure difference deviation; Indicates loading and unloading area; Indicates a heating chamber; It means spray room; Indicates area The pressure difference weight factor of Indicates area Set pressure difference; For in time The differential pressure data measured by the differential pressure sensor; According to the following formula 2, calculate the air volume deviation: in, Indicates at time Area Air volume deviation; Indicates a heating chamber; It means spray room; Indicates area The air volume weight factor; Indicates area Set air volume; For in time Air volume data measured by air volume sensor; According to the following formula 3, the first proportional valve opening is calculated : in, is the proportional control gain; is the integral control gain; is the differential control gain; It is the parameter for adjusting the amplitude of proportional valve; Adjust the parameters for the proportional valve frequency; Indicates time; According to the following formula 4, calculate the frequency of the built-in fan of the oven circulation system : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the pressure difference deviation suppression factor for fan frequency regulation; Indicates time; According to the calculated opening of the first proportional valve and frequency , the output frequency of the corresponding inverter and the opening of the proportional valve are adjusted through the PLC controller.

9. The spraying system according to claim 8, characterized in that: The control unit is also used for: According to the following formula 5, calculate the second proportional valve opening : in, is the proportional control gain; is the integral control gain; is the differential control gain; It is the parameter for adjusting the amplitude of proportional valve; Adjust the parameters for the proportional valve frequency; Indicates time; According to the following formula 6, calculate the frequency of the fresh air fan : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the pressure difference deviation suppression factor for fan frequency regulation; Indicates time; According to the calculated opening of the second proportional valve and frequency , the output frequency of the corresponding inverter and the opening of the proportional valve are adjusted through the PLC controller.

10. The spraying system according to claim 1, characterized in that: The control unit is specifically used for: Use VOC concentration sensor to obtain VOC concentration in the spray booth ; Use pressure sensor to obtain the pressure in the spray booth outlet duct ; The collected data is filtered and the filtered VOC concentration is calculated according to the following formulas 7 and 8. and the filtered outlet pressure : in, is the filter window size; According to the following formula 9, calculate the VOC concentration deviation : in, It is the pre-set target VOC concentration of the spray booth; is the weight factor for VOC concentration control; According to the following formula 10, calculate the pressure deviation : in, is the target air outlet pressure; is the pressure control weight factor; According to the following formula 11, calculate the exhaust fan frequency : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the current time; 0 in the definite integral represents the time when the fan starts working; According to the following formula 12, calculate the fresh air fan frequency : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the current time; 0 in the definite integral represents the time when the fan starts working; According to the following formula 13, calculate the circulation fan frequency : in, is the proportional control gain; is the integral control gain; is the differential control gain; is the current time; 0 in the definite integral represents the time when the fan starts working; is the dynamic adjustment factor; is the magnification factor; is the index inhibition factor; Based on the calculated exhaust fan frequency , Fresh air fan frequency And the circulation fan frequency The speed of the exhaust fan, fresh air fan and circulating fan is adjusted through the PLC controller to achieve stable control of the VOC concentration in the spray room.

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