A control system for saving electricity of a coating line water system

Abstract

The application discloses a kind of control system for coating line water system electricity saving, by waste heat reuse intercommunication pipeline structure communication cathode target material circulating cooling system and the pure water tank of cleaning ultrapure water supply system, cathode cooling high temperature cooling water is delivered to pure water tank, reduces electric heating equipment energy consumption.Waste heat reuse pipeline is equipped with security structure, and water quality is guaranteed by multistage precision filter, cooperate with pressure stabilizing pump, flow balance valve to stabilize pipeline water pressure and flow.Electricity-saving control unit uses PLC programmable main controller to collect waterway temperature, pure water tank liquid level signal, and intelligently controls pipeline on-off;Water tank high liquid level is cut off waste heat supply, cooling water backflow original cooling loop, and water temperature is insufficient to start electric heating temperature compensation.The application realizes cathode waste heat resource utilization, reduces cooling tower operating load, eliminates the water quality, water pressure hidden trouble brought by waste heat reuse, solves the double energy consumption problems of traditional coating line water system cleaning heating high energy consumption, cathode cooling waste heat waste.

Description

Technical Field

[0001] This invention belongs to the field of energy-saving control technology for vacuum coating production lines, and relates to a control system for saving electricity in the water system of a coating line. Background Technology

[0002] In the industrial continuous coating production of products such as optical glass, building curtain walls, automotive glass, and photovoltaic glass, the coating line is the core process, and its stable operation depends on the supporting utility system, among which the water system is particularly critical. This system mainly consists of two independent loops: one is an ultrapure water supply system that provides cleaning water for the pretreatment of the coating substrate, and the other is a circulating cooling system that cools the cathode target material in the vacuum chamber. These two water systems operate independently and are temperature-controlled independently, jointly undertaking the core functions of ensuring the cleanliness of the glass substrate, the working temperature of the cathode target material, and the overall process temperature stability. The stability of its operation and the level of energy consumption control not only directly affect the yield of the coated products but also constitute a significant part of the production line's operation and maintenance costs, making it a key energy-consuming unit in industrial coating production lines.

[0003] Currently, conventional coating line water systems in the industry generally adopt a traditional operating mode with two completely independent water circuits, coupled with conventional variable frequency and fixed-value temperature control passive control strategies. However, this mode has inherent technical defects, resulting in a large amount of ineffective energy consumption. Specifically, the problem is mainly reflected in two aspects: First, the energy consumption of the constant temperature process for cleaning water is extremely high. The coating cleaning process has strict process requirements for water temperature (approximately 40℃), while conventional room temperature pure water (approximately 20℃) cannot meet the standard. It is necessary to rely on high-power electric heating devices with a rated power of up to 200KW or more for continuous heating, which generates huge rigid power consumption in continuous production, significantly increasing the electricity cost of the production line.

[0004] Secondly, the waste heat generated during the cathode target cooling process is completely wasted, while also increasing cooling energy consumption. During vacuum coating, the cathode target generates a large amount of heat during continuous operation, causing the temperature of its circulating cooling water to rise to around 39°C. This temperature of hot water precisely meets the process requirements for cleaning water, but current technology directly introduces it into a cooling tower, where fans and pumps force it to cool to below 33°C before recycling. This process not only causes a large amount of clean waste heat to be lost into the environment without any recovery or utilization, but also consumes a significant amount of electricity due to the continuous full-load operation of the cooling tower's fans and pumps. This creates a double energy waste situation of waste heat and excessive power consumption due to forced cooling, indicating a huge potential for energy saving. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a control system for saving energy in the water system of a coating line, thereby solving the dual energy waste problem of high energy consumption heating of cleaning water and waste of waste heat from cathode cooling in the prior art.

[0006] This invention is achieved through the following technical solution: A control system for energy saving in a coating line water system includes: The waste heat recovery pipeline structure is connected between the outlet of the cathode target circulating cooling system and the pure water tank of the ultrapure water supply system for pretreatment and cleaning of the coating substrate, and is used to introduce the high temperature cooling water of the cathode target circulating cooling system into the pure water tank. The power saving control unit includes a PLC programmable main controller, a flow sensor, and a protection module. The PLC programmable main controller is connected to a temperature sensor installed on the cathode target circulating cooling system and the ultrapure water supply system, as well as a liquid level controller installed on the pure water tank. It is used to control the water circuit on and off in the waste heat recovery connecting pipeline structure according to the collected temperature and liquid level signals. The security structure, which is installed on the waste heat recovery connecting pipeline structure, includes a multi-stage precision filter, a pressure stabilizing pump and a flow balancing valve, used to filter the introduced high-temperature cooling water and stabilize its water pressure and flow rate.

[0007] Optionally, the waste heat recovery connecting pipeline structure is a bypass pipeline, with its inlet end connected to the outlet water pipe of the cathode target circulating cooling system and its outlet end connected to the pure water tank.

[0008] Optionally, the waste heat recovery connecting pipeline structure is equipped with a heat insulation layer throughout.

[0009] Optionally, the protection module is signal-connected to the electric heating device of the ultrapure water supply system for cleaning, and is used to activate the electric heating device when the water temperature in the pure water tank does not meet the process requirements.

[0010] Optionally, the protection module is signal-connected to the water replenishment solenoid valve and pump group on the waste heat recovery pipeline structure, and is used to close the water replenishment solenoid valve and pump group when the pure water tank is at a high liquid level.

[0011] Optionally, the protection module is also used to open the water replenishment solenoid valve and pump group when the pure water tank is at a low liquid level.

[0012] Optionally, the multi-stage precision filter is two or more filters arranged in series.

[0013] Optionally, the pressure-stabilizing pump is a variable frequency pressure-stabilizing pump.

[0014] Optionally, the flow balancing valve is a self-operated flow balancing valve.

[0015] Optionally, after the high-temperature cooling water of the cathode target circulating cooling system is introduced into the pure water tank through the waste heat recovery connecting pipeline structure, the unused cooling water flows back to the cathode target circulating cooling system through the original loop. Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a control system for energy saving in the water system of a coating line. This system establishes a media transport channel between the cathode target circulating cooling system and the pure water tank of the ultrapure water supply system for pretreatment and cleaning of the coating substrate through a waste heat recovery connecting pipeline structure. High-temperature cooling water with process-usable temperature generated by cathode cooling is directly transported to the cleaning pure water tank, recovering the waste heat originally lost through the cooling tower and supplying it to the cleaning process. This significantly reduces the temperature rise load of the electric heating equipment in the cleaning water circuit, reducing the high energy consumption caused by heating the cleaning water from the source. Simultaneously, a safety structure is mounted on the waste heat recovery connecting pipeline, relying on multi-stage precision filters to ensure ultrapure water quality, and a pressure stabilizing pump and flow balancing valve to stabilize the water pressure in the circuit. To avoid interference with the original production line operation during waste heat recovery, the energy-saving control unit relies on a PLC programmable main controller to collect two water circuit temperature and pure water tank level signals, and intelligently manage the on / off of the waste heat recovery pipeline water circuit. When the water tank is at a high level, the waste heat water supply is cut off and the cathode cooling water flows back to the original cooling circuit. When the temperature of the recovered cooling water is insufficient, the electric heating is automatically started to supplement the temperature. This not only realizes the resource utilization of cathode waste heat and reduces the heat dissipation load of the cooling tower to reduce the power consumption of cooling equipment, but also avoids the water quality and water pressure safety hazards caused by waste heat recovery. At the same time, it solves the dual energy waste problems of high-power electric heating continuous energy consumption in the cleaning process of the water system of the traditional coating line and direct release of cathode cooling waste heat and additional power consumption of the cooling tower.

[0016] Furthermore, the waste heat recovery connecting pipeline structure is a bypass pipeline, with its inlet end connected to the outlet water pipe of the cathode target circulating cooling system and its outlet end connected to the pure water tank. Here, the waste heat recovery connecting pipeline structure adopts the form of a bypass pipeline, with the inlet end connected to the outlet water pipe of the cathode target circulating cooling system and the outlet end connected to the pure water tank. Waste heat is transported only by adding a bypass, without the need to cut or modify the original main pipelines of the cathode cooling system and the cleaning water supply system. The construction and modification difficulty is low, and it will not destroy the original complete process loop of the two water systems. It can be installed in the coating line with no or minimal downtime, making the modification more adaptable. At the same time, it can flexibly control the diversion ratio of waste heat cooling water, without affecting the basic cooling function of the cathode cooling main loop, ensuring the continuous and stable operation of coating production.

[0017] Furthermore, the waste heat recovery connecting pipeline structure is equipped with an insulation layer throughout. This insulation layer significantly reduces the heat exchange loss between the high-temperature cooling water and the external environment during pipeline transportation, prevents the effective waste heat carried by the cathode cooling water from being lost during transportation, maximizes the recovery and utilization of the target material cooling waste heat, further reduces the start-up time and operating power of the electric heating device in the cleaning process, improves the waste heat recovery and utilization rate and the overall power saving effect of the system, and at the same time prevents condensation and dripping on the outer wall of the pipeline, protecting the surrounding electrical control, pump and valve equipment from water vapor corrosion.

[0018] Furthermore, the protection module is signal-connected to the electric heating device of the ultrapure water supply system for cleaning, and is used to activate the electric heating device when the water temperature in the pure water tank does not meet the process requirements. Here, the protection module establishes a signal connection with the electric heating device of the ultrapure water supply system for cleaning. When the temperature of the cooling water supplied to the pure water tank by waste heat recovery does not reach the temperature set by the cleaning process, the protection module can automatically trigger the electric heating device to compensate for the temperature difference. On the basis of making full use of the cathode waste heat, it accurately compensates for the temperature difference, ensuring that the cleaning water always stably meets the process constant temperature standard. It will not affect the glass cleaning quality and coating yield due to the low temperature of the waste heat supply water, thus taking into account both energy saving and consumption reduction and production process stability.

[0019] Furthermore, the protection module is signal-connected to the water replenishment solenoid valve and pump group on the waste heat recovery connecting pipeline structure. It is used to close the water replenishment solenoid valve and pump group when the pure water tank is at a high liquid level. Here, the protection module is linked with the water replenishment solenoid valve and pump group of the waste heat recovery connecting pipeline. When the liquid level in the pure water tank reaches the high threshold, the protection module promptly shuts off the water replenishment solenoid valve and pump group, stopping the supply of high-temperature cooling water to the pure water tank. This can prevent the pure water tank from overflowing, avoid waste of ultrapure water, and prevent pipeline overflow from soaking the equipment. At the same time, after the waste heat water supply is cut off in time, the cathode cooling water can flow back to the original cooling circuit, avoiding pressure buildup in the cooling water circuit and ensuring the stability of the cathode cooling system water pressure and the safe operation of the equipment.

[0020] Furthermore, the protection module is also used to open the water replenishment solenoid valve and pump group when the pure water tank is at a low liquid level. The protection module can open the water replenishment solenoid valve and pump group when the pure water tank is at a low liquid level, realize bidirectional automatic control of the liquid level of the waste heat recovery water supply, automatically replenish waste heat warm water when the water tank is short of water, continuously use cathode waste heat to replace electric heating, eliminate the need for manual start and stop of water supply pump valve, reduce manual operation intervention, maintain stable water level in cleaning water tank, ensure uninterrupted water supply for cleaning process, continuously exert the energy-saving effect of waste heat, and improve the automation level of system operation.

[0021] Furthermore, the multi-stage precision filter is a two-stage or higher filter arranged in series. Here, the multi-stage precision filter adopts a two-stage or higher series arrangement. The multi-layer filtration structure can intercept solid impurities of different particle sizes in high-temperature cooling water in stages. Compared with a single-stage filter, it has higher filtration accuracy and better interception effect. It can completely block impurities from entering the ultrapure water path of the cleaning, avoid impurities adhering to the glass substrate and causing pinholes and defects in the coating, protect the cleaning spray pipes and nozzles from clogging, stabilize the ultrapure water quality, and reduce the frequency of equipment cleaning and maintenance.

[0022] Furthermore, the pressure stabilizing pump is a variable frequency pressure stabilizing pump. Here, the pressure stabilizing pump selected is a variable frequency pressure stabilizing pump, which can automatically adjust the pump output power according to the real-time water pressure of the waste heat recovery pipeline, and dynamically balance the water pressure of the bypass pipeline. It can not only stably supply the cooling water required for the cleaning water tank, but also avoid the impact of excessive water pressure on the cleaning water circuit and insufficient water pressure leading to insufficient waste heat water supply flow. At the same time, the variable frequency regulation can reduce the power consumption of the pressure stabilizing pump itself during continuous operation under no-load and full-load conditions, further improving the energy-saving performance of the entire system.

[0023] Furthermore, the flow balancing valve is a self-regulating flow balancing valve. This valve can maintain a constant medium flow rate in the waste heat recovery pipeline without the need for external electrical control signals. It is unaffected by fluctuations in the main circuit water pressure of the cathode cooling system, and can stably supply a fixed flow rate of high-temperature cooling water to the cleaning water tank. This ensures that the waste heat recovery is stable and controllable, prevents drastic fluctuations in water tank temperature caused by sudden changes in flow rate, reduces frequent start-stop of the electric heating device, extends the service life of the heating equipment, and optimizes energy-saving effects.

[0024] Furthermore, after the high-temperature cooling water of the cathode target circulating cooling system is introduced into the pure water tank through the waste heat recovery connecting pipeline structure, the unused cooling water flows back to the cathode target circulating cooling system through the original loop. It is clear here that the high-temperature cooling water not taken by the pure water tank can flow back to the cathode target circulating cooling system through the original loop, forming a complete closed-loop water circuit. This realizes that the waste heat diversion and reuse and the independent circulation of the main cooling circuit do not conflict with each other. Even if the waste heat water supply branch is shut down, the cathode cooling water can still circulate and dissipate heat normally, without causing the cathode target cooling to be interrupted or damaged by overheating. This ensures that the vacuum coating cathode continues to operate at a constant temperature, and the fault tolerance and safety reliability of the entire system are greatly improved. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1This is a schematic diagram of the overall process flow of a control system for saving electricity in a coating line water system, as described in an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0029] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0030] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0032] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0033] The present invention will now be described in further detail with reference to the accompanying drawings: This invention discloses a control system for saving energy in the water system of a coating line, comprising: The waste heat recovery connecting pipeline structure is connected between the outlet of the cathode target circulating cooling system and the pure water tank of the ultrapure water supply system for pretreatment and cleaning of the coating substrate, and is used to introduce the high temperature cooling water of the cathode target circulating cooling system into the pure water tank. The power saving control unit includes a PLC programmable main controller, a flow sensor, and a protection module. The PLC programmable main controller is connected to a temperature sensor installed on the cathode target circulating cooling system and the ultrapure water supply system, as well as a liquid level controller installed on the pure water tank, and is used to control the water circuit on and off in the waste heat recovery connecting pipeline structure according to the collected temperature and liquid level signals. The security structure, which is installed on the waste heat recovery connecting pipeline structure, includes a multi-stage precision filter, a pressure stabilizing pump, and a flow balancing valve, for filtering the introduced high-temperature cooling water and stabilizing its water pressure and flow rate.

[0034] The waste heat recovery connection pipeline structure is a bypass pipeline, with its inlet end connected to the outlet water pipe of the cathode target circulating cooling system and its outlet end connected to the pure water tank.

[0035] Furthermore, the entire waste heat recovery pipeline structure is equipped with an insulation layer, which covers the outer wall of the pipeline. This reduces heat exchange between the high-temperature cooling water transported inside the pipeline and the external environment, minimizes heat loss of the high-temperature cooling water during the medium transport process, maximizes the retention of waste heat carried in the cathode cooling water, and improves the efficiency of waste heat recovery and utilization. This further reduces the workload of the electric heating device in the ultrapure water supply system. At the same time, the insulation layer can prevent condensation and dripping of water on the outer wall of the pipeline due to temperature differences, prevent water vapor corrosion of surrounding pumps, valves, and electrical control components, and improve the safety and stability of the entire system in long-term operation.

[0036] In a more preferred embodiment, the protection module is in signal connection with the electric heating device of the cleaning ultrapure water supply system, and is configured to activate the electric heating device when the water temperature in the pure water tank does not meet the process requirements. The protection module establishes a signal connection with the electric heating device of the cleaning ultrapure water supply system, and the protection module can receive the collected water temperature detection signal in the pure water tank for the cleaning machine, and compare the actual water temperature with the preset process temperature threshold; when the heat brought by the high-temperature cooling water reused into the pure water tank is insufficient to raise the water temperature to the process requirement standard, that is, when the water temperature in the pure water tank does not reach the process set temperature, the protection module outputs a control signal to activate the electric heating device, and the temperature difference is compensated by the electric heating device, so that the temperature of the cleaning water stably meets the cleaning process conditions of the coated substrate; on the basis of fully utilizing the cathode cooling waste heat to reduce heating energy consumption, the water temperature of the cleaning process is guaranteed to continuously meet the standard, the fluctuation of cleaning quality caused by insufficient temperature of waste heat supply water is avoided, and both the energy-saving effect of the system and the normal production stability of the production line are considered.

[0037] Further, the protection module is in signal connection with the water replenishing solenoid valve and the pump set on the waste heat reuse communication pipeline structure, and is configured to close the water replenishing solenoid valve and the pump set when the pure water tank is at a high liquid level. The protection module is in signal connection with the water replenishing solenoid valve and the pump set on the waste heat reuse communication pipeline structure, the protection module receives the liquid level signal collected by the liquid level detection device matched with the pure water tank for the cleaning machine in real time, and compares the real-time liquid level with the preset high liquid level threshold; when it is detected that the pure water tank is in a high liquid level state, the protection module outputs a control signal to synchronously close the water replenishing solenoid valve and the pump set, and cut off the passage for the waste heat reuse communication pipeline structure to deliver high-temperature cooling water to the pure water tank. On the one hand, it prevents the pure water tank from overflowing caused by continuous water inflow, avoids ultrapure water waste and accumulated water soaking surrounding equipment; on the other hand, after the waste heat water supply is stopped, the cooling water output by the coating cathode heat source can normally flow back to the cathode target circulating cooling system, prevent the pipeline from being pressured due to continuous water inflow in the waste heat reuse branch, ensure the water pressure stability of the main cathode cooling loop, and improve the operation safety performance of the whole system.

[0038] In a more preferred embodiment, the protection module is further configured to activate the water replenishment solenoid valve and pump group when the pure water tank is at a low liquid level. The protection module continuously receives liquid level data from the liquid level detection device of the pure water tank for the cleaning machine and compares the real-time liquid level with the low liquid level threshold preset by the system. When the liquid level of the pure water tank is detected to drop to the low liquid level threshold, the protection module outputs a control signal to simultaneously activate the water replenishment solenoid valve and pump group, opening the water supply passage of the waste heat recovery pipeline structure, and continuously supplying the high-temperature cooling water generated by the cathode heating source to the pure water tank for the cleaning machine. The waste heat from the cathode cooling is continuously used to replenish the water used in the cleaning process, and the water level in the tank is maintained by the waste heat warm water, reducing the frequency of activation of the electric heating device, realizing automated linkage control of the liquid level, eliminating the need for manual on-site operation to start and stop the water supply equipment, continuously exerting the energy-saving effect of waste heat recovery, and ensuring continuous and stable water supply for the cleaning process.

[0039] In addition, the multi-stage precision filter consists of two or more stages arranged in series. Each stage of the filter is arranged sequentially along the medium flow direction of the cooling water in the waste heat recovery connecting pipeline structure. Different stages of the filter can be set with different filtration precision, which can intercept solid impurities of different particle sizes in the high-temperature cooling water in stages. Compared with the single-stage filtration structure, it has a stronger impurity interception capability. It effectively prevents impurities from entering the ultrapure water supply system with the cooling water, prevents impurities from clogging the cleaning spray pipeline and nozzles, and ensures that the quality of the cleaning water meets the cleaning requirements of the coating substrate. It avoids quality defects such as pinholes and surface defects in the coating products caused by water impurities. Moreover, the staged filtration can distribute the filtration load, slow down the clogging speed of single-stage filter elements, extend the filter element replacement cycle, and reduce the daily maintenance cost of the system.

[0040] More specifically, the pressure-stabilizing pump is a variable frequency pressure-stabilizing pump, and the flow balancing valve is a self-regulating flow balancing valve. The variable frequency pressure-stabilizing pump can dynamically adjust its output power according to the real-time water pressure in the waste heat recovery pipeline structure, maintaining stable water supply pressure and avoiding large fluctuations in water pressure. The self-regulating flow balancing valve does not require external electrical control signals and can autonomously maintain a constant cooling water flow rate in the pipeline, unaffected by changes in the main circuit water pressure of the cathode target circulating cooling system. The two work together to ensure that the pressure and flow rate of the bypass waste heat supply water are stable and controllable in the long term, preventing drastic fluctuations in the water temperature of the pure water tank used in the cleaning machine caused by sudden changes in water supply flow, reducing frequent start-stop of the electric heating device, stabilizing the waste heat recovery supply, optimizing the system's energy-saving effect, and avoiding pressure shocks that could affect the operation of the original two water circuit systems, thus improving the overall system's operational stability.

[0041] More specifically, the high-temperature cooling water of the cathode target circulating cooling system is introduced into the pure water tank through the waste heat recovery connecting pipeline structure. The unused cooling water flows back to the cathode target circulating cooling system through the original loop. A portion of the high-temperature cooling water output by the cathode target circulating cooling system is sent to the pure water tank of the cleaning machine to realize waste heat recovery and utilization. When the waste heat recovery channel is shut down or the pure water tank no longer accepts cooling water, the high-temperature cooling water can smoothly flow into the original cathode cooling circulation loop to continue to participate in circulating heat exchange without the need to add an independent return water pipeline. This return method ensures that the cathode target cooling water flow will not be interrupted or stagnant. The waste heat recovery bypass branch and the cathode cooling main loop are compatible and non-restrictive. Even if the waste heat recovery water supply operation status is switched, the cathode target can still obtain continuous and stable cooling guarantee, effectively preventing the coating cathode heat source from overheating due to insufficient cooling, ensuring the continuous and stable operation of vacuum coating production, and improving the fault tolerance and safety reliability of the entire control system.

[0042] This invention relates to a dual-water-path waste heat recovery structure adapted to coating lines. It breaks away from the traditional design concept of two completely independent water paths, and completely transfers the waste heat generated in the cathode cooling process to the constant temperature cleaning water process through a closed pipeline. This transforms the waste heat that was originally lost directly through the cooling tower into a usable heat source for the cleaning process, realizing the recycling of waste heat resources. The entire waste heat recovery pipeline adopts a closed insulation and pressure stabilization integrated design, and is equipped with multi-stage filtration and purification components in the pipeline, which can effectively isolate impurities in the water path and prevent cathode cooling water from mixing into the cleaning water path and causing water pollution problems. The waste heat recovery process does not change the original main process pipeline and will not interfere with the normal production conditions of vacuum coating and glass substrate cleaning. This system is easy to retrofit and construct, requiring no large-scale dismantling of existing water system equipment. The project has low investment costs, stable energy savings, a short payback period, and safe and stable operation. It is highly adaptable to coating production lines of different specifications and capacities, specifically addressing the core technical shortcomings of existing coating line water systems, such as high overall energy consumption and significant waste of cathode waste heat. By recovering waste heat, it significantly reduces the overall power consumption of the water system, directly cutting daily production electricity costs for enterprises. This structure can be widely applied to various industrial coating production lines, including architectural glass, photovoltaic glass, and building material coating. Compared to existing traditional independent water circuit temperature control solutions, it has significant advantages in versatility, practicality in on-site use, and long-term energy-saving operational stability. It has a low threshold for industrial implementation, substantial energy savings, and strong industrial promotion value, fully meeting the core operational and environmental needs of manufacturing enterprises to save energy, reduce production and operating expenses, and achieve low-carbon compliant production.

[0043] Example 2 To further explain the technical solution of the present invention, this embodiment is used as an example: like Figure 1As shown, this invention establishes a waste heat recovery synergistic heat exchange + closed-loop intelligent energy-saving control system for coating lines. The overall structure is a modification and addition to the existing water system, without damaging the original process water circuit or affecting normal coating production. Specifically: First, the cathode cooling main circulation loop.

[0044] The core cooling function of the system is undertaken by a closed-loop circuit consisting of the coated cathode heat source, the heat exchange system, and the external circulation cooling tower. The high-temperature cooling water generated by the coated cathode heat source during operation is first transported to the heat exchange system for cooling. In the heat exchange system, the high-temperature cooling water exchanges heat with the cooling medium from the external circulation cooling tower, transforming into low-temperature cooling pure water. Subsequently, the low-temperature cooling pure water is pumped back to the coated cathode heat source to maintain the target material at a constant temperature, while the external circulation cooling tower is responsible for removing the exchanged heat, ensuring the thermal balance of the entire cooling cycle.

[0045] Second, the waste heat recovery and water purification branch.

[0046] To achieve cascaded energy utilization, the system draws a waste heat recovery branch from the high-temperature outlet of the coating cathode heat source. This high-temperature cooling water, carrying a large amount of heat energy, first enters the water filtration system before entering the main heat exchange system. After precision filtration, the high-temperature pure water, free of impurities, is sent to the constant flow water supply system. This step not only recovers the heat energy that would otherwise be wasted by the cooling tower, but also ensures the stability of the subsequent cleaning water flow through the constant flow water supply system, providing a basic water source that meets the temperature requirements for the cleaning process.

[0047] Third, a constant temperature and replenishment system for the cleaning water.

[0048] The final temperature control of the cleaning water is ensured by a series system consisting of a pure water tank in the water room, an electrically heated water tank, and a pure water tank for the cleaning machine. After preheated pure water from the constant flow water supply system enters the pure water tank for the cleaning machine, if the temperature does not reach the process standard, the system can compensate with auxiliary heating from the electrically heated water tank. Simultaneously, the pure water tank in the water room serves as a basic water source reserve, replenishing the system with ambient temperature pure water according to liquid level requirements. This dual guarantee mechanism of waste heat preheating + electric heating fine-tuning ensures that the pure water ultimately supplied to the cleaning machine can be stably maintained at a process temperature of approximately 40℃, with a constant flow rate.

[0049] Fourth, the overall coupled operation mechanism of the system.

[0050] In summary, this new system breaks away from the traditional model where cooling and cleaning water circuits are completely independent. By converting the high-temperature wastewater generated from cathode cooling into hot water for the cleaning process, the system achieves deep coupling of the two water circuits at the thermal energy level. The external circulation cooling tower only bears the basic heat dissipation load, while high-grade waste heat is preferentially extracted for cleaning water supply. Combined with water filtration and constant flow control, this forms a comprehensive energy-saving water system integrating high-efficiency cooling, waste heat recovery, precision filtration, and constant-temperature water supply, fundamentally solving the problem of high heating energy consumption and wasteful cooling heat in the traditional model.

[0051] The hardware structure of the power-saving control system for the water system of the coating line in this invention consists of three main parts: a pipeline heat exchange structure, a control unit, and a voltage and flow stabilization guarantee unit. The specific structure is as follows: (1) Waste heat recovery connecting pipeline structure The existing cathode cooling circulating water circuit and ultrapure water cleaning circuit are retained. High-temperature cooling water is drawn from the coating cathode heat source and introduced into the cleaning machine's pure water tank via a newly added bypass waste heat recovery pipeline. This high-temperature cooling water is then filtered through a water quality filtration system and a constant flow water supply system. The above-mentioned equipment system ensures that the water quality meets standards and that the water pressure and flow rate are stable. The entire recovery pipeline is fully sealed and insulated to eliminate heat loss.

[0052] (2) Energy-saving control unit Equipped with a PLC programmable main controller, flow sensor, and protection module; the controller synchronously collects the cathode cooling water temperature and the cleaning water tank temperature, and controls the entire set of equipment in a coordinated manner, stopping or starting the water supply when the pure water tank of the cleaning machine is at a high or low liquid level.

[0053] (3) Voltage and current stabilization and safety protection structure Multi-stage precision filters are installed in the reuse pipeline to prevent impurities from entering the cleaning water circuit and ensure that the ultrapure water quality meets the standards. A pressure stabilizing pump and flow balancing valve are provided to ensure that the water pressure in the cooling water circuit and the cleaning water circuit remains stable within the process safety range during the waste heat recovery process, without interfering with the normal operation of vacuum coating and substrate cleaning.

[0054] Example 3 In the existing process system, the process water for the cleaning machine and the cooling water for the cathode target in the coating production line both use ultrapure water, and the two water circuits operate independently. The initial temperature of the pure water entering the cleaning process is about 20.3℃, which needs to be continuously heated to 39℃ by electric heating equipment with a rated power of over 200KW to meet the glass cleaning process standards. The cooling water after heat exchange in the cathode target is stably maintained at 39℃. Under traditional operating conditions, this high-temperature cooling water is directly transported to the cooling tower, where it is forced to cool down to 33℃ by fans and circulating water pumps before being returned for circulation. The original operating mode has dual energy losses. On the one hand, the cleaning process relies on high-power electric heating equipment to continuously raise the temperature, resulting in high electricity consumption during production. On the other hand, the waste heat of 39℃ carried by the cathode cooling water is not recovered and utilized, and the heat is directly dissipated to the outside. At the same time, the cooling tower equipment operates at full load, generating additional cooling energy consumption. There is potential for heat exchange between the two water circuits, making it possible to optimize and upgrade for energy conservation.

[0055] This invention adds a waste heat recovery bypass channel, which sequentially filters and purifies the cathode cooling water (39°C) and regulates its constant pressure and flow before delivering it to the pure water tank for the cleaning machine. The water supply flow rate of the recovery pipeline can be adjusted according to the actual operating conditions of the production line, and is set to 3m³ under normal operating conditions. 3 / h; The cleaning machine uses a pure water tank equipped with a liquid level acquisition device to achieve linkage control. When the water level in the tank reaches the high-level threshold, the water replenishment solenoid valve on the reuse pipeline and the delivery pump group are simultaneously shut down, and the cathode cooling water is no longer delivered to the cleaning water circuit, but flows back to the original cathode cooling circulation loop. The system synchronously collects the cathode cooling water temperature and compares it with the water temperature in the cleaning water tank. When the cathode reuse cooling water temperature is lower than the 39℃ standard required by the cleaning process, the heating unit of the electric heating water tank is automatically started to compensate for the water temperature difference. After the water temperature in the tank reaches the process set value, the heating unit automatically stops.

[0056] This system recovers waste heat from cathode cooling to power the cleaning process, significantly reducing the operating load of electric heating equipment. Under continuous production conditions, the energy saving rate for electric heating in the cleaning process can reach over 87%, reducing daily heating power consumption by over 4,000 kWh, substantially lowering fixed heating power consumption in the cleaning process. With the waste heat from the cathode recovered, the heat dissipation load on the cooling tower is significantly reduced, allowing the cooling tower fan and cooling circulating water pump to switch to variable frequency load reduction mode. The overall energy saving rate of the cooling system exceeds 6%, eliminating energy loss caused by ineffective heat dissipation. After the entire coating line's water system is upgraded, overall energy consumption is significantly reduced, effectively lowering the monthly and annual electricity costs of the production line, reducing carbon emissions in the production process, and meeting relevant requirements for low-carbon industrial production.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control system for energy saving in a water system of a coating line, characterized in that, include: The waste heat recovery pipeline structure is connected between the outlet of the cathode target circulating cooling system and the pure water tank of the ultrapure water supply system for pretreatment and cleaning of the coating substrate, and is used to introduce the high temperature cooling water of the cathode target circulating cooling system into the pure water tank. The power saving control unit includes a PLC programmable main controller, a flow sensor, and a protection module. The PLC programmable main controller is connected to a temperature sensor installed on the cathode target circulating cooling system and the ultrapure water supply system, as well as a liquid level controller installed on the pure water tank. It is used to control the water circuit on and off in the waste heat recovery connecting pipeline structure according to the collected temperature and liquid level signals. The security structure, which is installed on the waste heat recovery connecting pipeline structure, includes a multi-stage precision filter, a pressure stabilizing pump and a flow balancing valve, used to filter the introduced high-temperature cooling water and stabilize its water pressure and flow rate.

2. The control system for energy saving in the water system of a coating line according to claim 1, characterized in that, The waste heat recovery connection pipeline structure is a bypass pipeline, with its inlet end connected to the outlet water pipe of the cathode target circulating cooling system and its outlet end connected to the pure water tank.

3. The control system for energy saving in the water system of a coating line according to claim 1, characterized in that, The waste heat recovery pipeline structure is equipped with a thermal insulation layer throughout.

4. The control system for energy saving in the water system of a coating line according to claim 1, characterized in that, The protection module is connected to the electric heating device of the ultrapure water supply system for cleaning, and is used to activate the electric heating device when the water temperature in the pure water tank does not meet the process requirements.

5. The control system for energy saving in the water system of a coating line according to claim 1, characterized in that, The protection module is signal-connected to the water replenishment solenoid valve and pump group on the waste heat recovery pipeline structure, and is used to close the water replenishment solenoid valve and pump group when the pure water tank is at a high liquid level.

6. The control system for energy saving in the water system of a coating line according to claim 5, characterized in that, The protection module is also used to open the water replenishment solenoid valve and pump group when the pure water tank is at a low liquid level.

7. The control system for energy saving in the water system of a coating line according to claim 1, characterized in that, The multi-stage precision filter is a filter consisting of two or more stages arranged in series.

8. The control system for energy saving in the water system of a coating line according to claim 1, characterized in that, The pressure-stabilizing pump is a variable frequency pressure-stabilizing pump.

9. The control system for energy saving in the water system of a coating line according to claim 1, characterized in that, The flow balancing valve is a self-operated flow balancing valve.

10. The control system for energy saving in the water system of a coating line according to claim 1, characterized in that, The high-temperature cooling water of the cathode target circulating cooling system is introduced into the pure water tank through the waste heat recovery connecting pipeline structure, and the unused cooling water flows back to the cathode target circulating cooling system through the original loop.

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