Dcs intelligent temperature control system and method for float glass annealing furnace

Abstract

The present application relates to the technical field of float glass production, in particular to a DCS intelligent temperature control system and method for a float glass annealing furnace. The DCS intelligent temperature control system comprises: an input unit for setting process parameters; a processing unit for determining temperature thresholds of each zone according to the process parameters, adjusting the air supply frequency of the air fan in the annealing furnace through a fan drive module, and adjusting the valve position size of the air duct in the annealing furnace through a valve position adjustment module. A monitoring unit is used to monitor the temperature of each zone. The processing unit also adjusts the working conditions of the fan drive module and the valve position adjustment module according to the monitoring data of the monitoring unit. By obtaining the process parameters and combining the process characteristics of different zones of the annealing furnace, the temperature thresholds of each zone are determined, and then the temperature of each zone of the annealing furnace is adjusted by adjusting the air supply frequency of the air fan and the valve position size of the air duct, so that the temperature of each zone is accurately adjusted, the use frequency of the annealing furnace is reduced, and energy saving is achieved.

Description

Technical Field

[0001] This invention relates to the field of float glass production technology, and in particular to a DCS intelligent temperature control system and method for float glass annealing furnaces. Background Technology

[0002] The float glass annealing furnace is the core equipment on the float glass production line. Its function is to precisely control temperature changes. Specifically, the float glass annealing furnace is usually divided into several zones according to process functions. Common zones include Zone A, Zone B, Zone C, Zone D, RET (R zone), Zone E, and Zone F. Among them, Zones A, B, and C are the front zones, Zones R and F are the rear zones, and Zones D and E are the transition zones. These zones undertake different thermal control tasks during the annealing process, with the aim of eliminating or reducing the thermal stress inside the glass sheet and preventing the glass from cracking during subsequent processing or use.

[0003] In traditional float glass production, annealing furnace temperature control largely relies on manual experience or semi-automatic control systems. PID parameter settings use a uniform mode. For example, Chinese patent CN222434336U discloses an annealing furnace cooling air control system based on DCS centralized control. This system includes an annealing furnace cooling air control system where the outlet duct of the RET zone fan M1 and the natural cooling air duct are both connected to a mixing air duct. The mixing air duct mixes the natural cooling air from the natural cooling air duct with the extracted hot air from the annealing furnace to obtain mixed air, which is then supplied to the air ducts in the upper and lower sections of the RET zone glass strip. Each air duct in the upper and lower sections of the RET zone glass strip is equipped with a regulating valve at the RET zone air duct. The output of the temperature sensing element is connected to the input of the DCS control module. The output of the DCS control module is connected to the RET zone fan M1 via a RET zone frequency converter. The DCS control module is also connected to the control terminals of the natural cooling air control valve and the regulating valves at the RET zone air ducts. The core of this system lies in the centralized control using a DCS module. The system controls the temperature and total air volume of the mixed air by mixing the extracted hot air from the kiln with naturally cooled air in the ducts and automatically adjusting the fan speed and the opening of the naturally cooled air valve based on the real-time temperature signal fed back by the temperature sensing element. Subsequently, the DCS further controls the regulating valves at the air ducts of each zone above and below the glass strip in the RET area.

[0004] Existing technologies do not differentiate configurations based on the process characteristics of different temperature zones in annealing kilns. Furthermore, to maintain the stability of the annealing process, the industry generally adopts a "temperature preservation priority" operation strategy, which involves fixing the air inlet opening and maintaining a high fan frequency to ensure uniform temperature inside the kiln.

[0005] The existing technology has uniform temperature control parameters, and does not distinguish the priority between the front zone (zones A, B, and C) and the rear zone (zones R and F), which makes it impossible to achieve precise energy saving while ensuring process stability. In order to maintain the temperature inside the kiln, the fan operates at a high frequency for a long time, and the air inlet opening is fixed, resulting in significant energy waste. Summary of the Invention

[0006] The purpose of this invention is to overcome the energy waste caused by the lack of zoned optimization of temperature control parameters and the long-term maintenance of high fan frequency in the existing technology, and to provide a DCS intelligent temperature control system and method for float glass annealing furnaces.

[0007] In a first aspect, the present invention provides a DCS intelligent temperature control system for a float glass annealing furnace, comprising: an input unit, a processing unit, a fan drive module, a valve position adjustment module, and a monitoring unit. The input unit is used to set process parameters. The processing unit determines a temperature control scheme based on the process parameters and controls the operating conditions of the fan drive module and the valve position adjustment module according to the temperature control scheme. Preferably, the temperature control scheme includes temperature thresholds for each zone. The fan drive module, in response to the control of the processing unit, adjusts the air supply frequency of the fan in the annealing furnace. The valve position adjustment module, in response to the control of the processing unit, adjusts the valve position of the air duct in the annealing furnace. The monitoring unit is used to acquire monitoring data. The processing unit also regulates the operating conditions of the fan drive module and the valve position adjustment module based on the monitoring data.

[0008] According to a preferred embodiment, the process parameters include: glass specifications, conveying speed of the annealing furnace, and number of ventilation openings in each zone.

[0009] According to a preferred embodiment, the processing unit is equipped with a database module. The database module pre-stores several temperature control schemes. The processing unit matches a temperature control scheme from the database module based on the specifications of the glass and the conveying speed of the annealing furnace.

[0010] According to a preferred embodiment, the monitoring data includes: ambient temperature and the temperature of each zone inside the annealing furnace.

[0011] According to a preferred embodiment, the processing unit performs PID control on the operating conditions of the fan drive module and the valve position adjustment module based on the monitoring data and the temperature control scheme.

[0012] According to a preferred embodiment, in the front zone of the annealing kiln, the processing unit adjusts the air supply frequency of the fan through the fan drive module to make the temperature reach the temperature threshold.

[0013] According to a preferred embodiment, in the front zone of the annealing kiln, when the air supply frequency of the blower reaches the upper limit of the operating condition and the temperature does not reach the temperature threshold, the processing unit adjusts the valve position of the air duct in the annealing kiln through the valve position adjustment module.

[0014] According to a preferred embodiment, in the rear zone of the annealing furnace, the valve position adjustment module adjusts the valve position of the air duct in the annealing furnace to make the temperature reach the temperature threshold.

[0015] According to a preferred embodiment, in the rear zone of the annealing kiln, when the valve position of the air duct reaches the upper limit of the operating condition and the temperature does not reach the temperature threshold, the processing unit adjusts the air supply frequency of the fan through the fan drive module.

[0016] In a second aspect, the present invention also provides a DCS intelligent temperature control method for a float glass annealing furnace, which uses a DCS intelligent temperature control system for a float glass annealing furnace provided by the present invention to control the temperature of the annealing furnace.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] This invention provides a DCS intelligent temperature control system for float glass annealing furnaces. By acquiring process parameters and combining them with the process characteristics of different zones in the annealing furnace, the system determines the temperature threshold for each zone. Then, by adjusting the air supply frequency of the blower and the valve position of the air duct, the system regulates the temperature of each zone in the annealing furnace. This makes the temperature regulation of each zone in the annealing furnace independent of each other and reduces the frequency of use in the annealing furnace, thereby achieving precise energy saving while ensuring process stability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the composition of a DCS intelligent temperature control system for a float glass annealing furnace according to the present invention.

[0020] Figure 2 This is a schematic diagram of a float glass annealing furnace using a DCS intelligent temperature control system. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0022] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0023] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0024] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0025] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0026] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0027] Example 1 This embodiment provides a DCS intelligent temperature control system for a float glass annealing furnace. See also... Figure 1 The DCS intelligent temperature control system for a float glass annealing furnace includes: an input unit, a processing unit, a fan drive module, a valve position adjustment module, and a monitoring unit. The input unit is used to set process parameters. The processing unit determines the temperature control scheme based on the process parameters and controls the operating conditions of the fan drive module and the valve position adjustment module according to the temperature control scheme. Preferably, the temperature control scheme includes temperature thresholds for each zone. The fan drive module, in response to the control of the processing unit, adjusts the air supply frequency of the fan in the annealing furnace. The valve position adjustment module, in response to the control of the processing unit, adjusts the valve position of the air duct in the annealing furnace. The monitoring unit is used to acquire monitoring data. The processing unit also regulates the operating conditions of the fan drive module and the valve position adjustment module based on the monitoring data.

[0028] The DCS intelligent temperature control system for the float glass annealing furnace provided in this embodiment obtains process parameters and combines them with the process characteristics of different zones of the annealing furnace to determine the temperature threshold of each zone. Then, by adjusting the air supply frequency of the blower and the valve position of the air duct, the temperature of each zone of the annealing furnace is regulated, so that the temperature regulation of each zone of the annealing furnace is independent of each other, and the frequency of use in the annealing furnace is reduced, thereby achieving precise energy saving while ensuring process stability.

[0029] Example 2 This embodiment is a further explanation of Embodiment 1, and repeated content will not be repeated.

[0030] See Figure 2 Each fan in each zone of the glass furnace is equipped with an independent fan drive module; each zone's duct valve is also equipped with an independent valve position adjustment module. Using the aforementioned fan drive module and valve position adjustment module, the processing unit can precisely adjust the operating conditions of each fan and each valve in the annealing furnace.

[0031] Preferably, the process parameters include: glass specifications, annealing furnace conveying speed, and the number of ventilation openings in each zone. Preferably, the glass specifications include: geometric parameters such as thickness, as well as: cutting difficulty, usage requirements, etc.

[0032] Preferably, the processing unit is equipped with a database module. The database module pre-stores several temperature control schemes. The processing unit matches the temperature control schemes from the database module according to the specifications of the glass and the conveying rate of the annealing furnace, thereby determining the temperature parameters of each functional zone of the annealing furnace.

[0033] Preferably, air vents are provided on and under the conveyor plate in zones A, B, and C of the annealing kiln, and are arranged as left side air duct L2, secondary left air duct L1, middle air duct M, secondary right air duct R1, and right side air duct R2 along the width direction of the conveyor plate.

[0034] Preferably, the temperature control scheme determines the temperature parameters of each functional area according to the glass production specifications, forming a temperature control scheme as shown in the table below.

[0035] Table 1: Examples of Temperature Control Solutions

[0036] In Table 1, B1 and B2 of the annealing zones are both zone B, and R1 and R2 are both zone R. The temperature control scheme provides the temperature thresholds for each zone and each duct.

[0037] Preferably, the monitoring data includes: ambient temperature and the temperature of each zone inside the annealing furnace. Preferably, the processing unit performs PID control on the operating conditions of the fan drive module and the valve position adjustment module based on the monitoring data and the temperature control scheme.

[0038] Preferably, the monitoring unit includes temperature sensors disposed in each functional area.

[0039] The processing unit can adjust the fan drive module and valve position adjustment module corresponding to the functional area of ​​the temperature sensor based on the temperature collected in real time by the temperature sensor, so that the temperature of the functional area of ​​the temperature sensor reaches the threshold.

[0040] Preferably, in the front zone of the annealing furnace, the processing unit adjusts the air supply frequency of the fan through the fan drive module to make the temperature reach the temperature threshold.

[0041] Preferably, for the front zone of the annealing furnace, when the blower's air supply frequency reaches the upper limit of the operating condition and the temperature does not reach the temperature threshold, the processing unit adjusts the valve position of the air duct in the annealing furnace through the valve position adjustment module.

[0042] Preferably, in the rear zone of the annealing furnace, the valve position adjustment module adjusts the valve position of the air duct in the annealing furnace to make the temperature reach the temperature threshold.

[0043] Preferably, in the rear zone of the annealing furnace, when the valve position of the air duct reaches the upper limit of the operating condition and the temperature does not reach the temperature threshold, the processing unit adjusts the air supply frequency of the fan through the fan drive module.

[0044] Natural cooling is used in the transition zones (Zones D and E) of the annealing kiln, without the installation of air duct control.

[0045] Example 3 This embodiment provides a DCS intelligent temperature control method for a float glass annealing furnace, which uses a DCS intelligent temperature control system for a float glass annealing furnace as described in Embodiment 1 or Embodiment 2 to control the temperature of the annealing furnace.

[0046] In traditional float glass production, annealing furnace temperature control relies heavily on manual experience or semi-automated control systems. PID parameters are set in a uniform pattern without differentiation based on the specific process characteristics of different temperature zones within the annealing furnace. Furthermore, to maintain annealing process stability, the industry generally adopts a "temperature preservation priority" operating strategy, typically placing annealing furnaces in factory workshops rather than in the open air. During production, windows near the annealing furnace in the workshop must be closed, and the opening of the furnace's air inlet must be fixed. A consistently high fan frequency is maintained to ensure temperature uniformity within the furnace. Additionally, in traditional float glass production, the cleaning cycle for annealing furnace air inlets and other pipes is lengthy, often only being performed after significant blockages have occurred. When producing special-specification glass such as thin sheets, annealing process parameters for conventional thickness glass are also used without dynamic adjustments based on product characteristics.

[0047] The following problems exist in traditional float glass production. 1. High energy consumption Traditional temperature control uses uniformly configured PID parameters, without prioritizing the front zone (zones A, B, C) and the rear zone (zones R, F), making it impossible to achieve precise energy savings while ensuring process stability. To maintain the kiln temperature, high fan frequencies are maintained for extended periods, and window and air inlet openings are fixed, failing to utilize natural outdoor cooling sources to lower the medium temperature. Energy conservation is particularly critical during cold weather, such as autumn and winter. Float process production generally uses conventional process control, and the fan frequency is not specifically optimized, resulting in additional energy consumption.

[0048] Glass thickness is a key factor in determining the tempering or annealing process parameters. Conventional float glass production processes do not specifically optimize the fan frequency based on glass thickness.

[0049] Compared to thick glass sheets, thin glass sheets have different heat absorption and dissipation characteristics, requiring lower heating and cooling intensities. During the heating phase, thin sheets require a "high-temperature, short-time" heating method to prevent overheating and deformation. During the cooling phase, the required air pressure is inversely proportional to the square of the glass thickness; therefore, the process requirements for airflow and pressure are significantly lower for thin sheets compared to thick sheets. When using the same process as thick sheets, the opening of dampers or valves in the entire temperature control system is larger, resulting in lower overall resistance in the piping system. Furthermore, the use of conventional processes in thin glass production, without optimized fan frequency, causes the fans to "idle" or "overwork" in a low-resistance, low-demand temperature control system, significantly deviating from their efficient operating range and resulting in substantial energy waste.

[0050] 2. Low equipment maintenance efficiency The cleaning cycle of the air inlet duct is not fixed. When the duct is blocked by debris, it will increase the ventilation resistance, forcing the fan to increase its frequency to maintain the air volume. This not only increases energy consumption, but also shortens the service life of the fan.

[0051] 3. Labor costs and process risks coexist. Relying on manual temperature control requires operators to continuously monitor changes in the kiln temperature and frequently adjust the equipment. This is labor-intensive, distracting, and prone to human error that can cause fluctuations in the annealing process, affecting the quality of glass products.

[0052] 4. Insufficient level of automation Semi-automated or manual control modes cannot dynamically adjust process parameters according to weather changes or product specification differences, which limits the improvement of production efficiency and makes it difficult to meet the needs of modern manufacturing for refined and intelligent production.

[0053] Preferably, the DCS intelligent temperature control system of the float glass annealing furnace involved in Example 1 or Example 2 is used to control the temperature of the annealing furnace. After inputting process parameters such as the thickness of the glass to be processed, the cutting difficulty, the usage requirements, the conveying speed of the annealing furnace, and the number of ventilation openings in each zone, the temperature of each functional zone can be automatically controlled during the glass production process.

[0054] DCS automatic control effectively reduces the frequency of manual adjustments, lowers the labor intensity and attention required of operators, and allows staff to devote more energy to other key production processes.

[0055] Preferably, when performing PID control on the temperature of the front zone (zones A, B, and C), the processing unit prioritizes adjusting the fan frequency and then adjusts the valve position to maintain a stable annealing temperature regime in the front zone.

[0056] After being formed, float glass has an "M"-shaped thickness, with a thickness of 6... For example, with a 3660mm specification, the thickness distribution is 5.823 / 5.868 / 5.832 / 5.854 / 5.821mm. To obtain glass sheets with good cutting properties and low stress, thicker areas require increased cooling, while thinner areas can have their cooling airflow reduced. Therefore, the valve position in the pre-annealing furnace is essentially "M"-shaped. The "M" shape can be adjusted according to different thicknesses to eliminate or reduce internal thermal stress in the glass sheet, achieving good cross-sections and longitudinal sections. The pre-annealing zone cools the glass from 600℃ to 400℃. Improper cooling in this zone can cause significant permanent stress. Therefore, the valve opening in the pre-annealing zone is a key factor in reducing the stress distribution across the thickness and width of the glass strip. Using an "M"-shaped valve position reduces the cooling difference between different layers of glass, thus reducing permanent stress.

[0057] In the temperature control of the front zone (zones A, B, and C) of the float glass annealing furnace, the strategy of prioritizing the adjustment of the fan frequency and then adjusting the valve position follows the optimization principle of "fast first, slow later; coarse first, fine later" in process control, which can more effectively balance the dynamic response speed and steady-state control accuracy of the system.

[0058] Specifically, changing the fan frequency directly affects the motor speed, rapidly altering airflow and pressure, resulting in a quick and significant temperature regulation effect within the kiln. This is analogous to the proportional (P) action in PID control, effectively suppressing the expansion of temperature deviations immediately. Valve position adjustments, on the other hand, are relatively gradual, altering the resistance characteristics of the air duct. Their impact on airflow is delayed, making them more suitable for fine-tuning, similar to the integral (I) action, used to eliminate steady-state residual error. Adjusting the valve position first results in a slow system response, potentially leading to temperature overshoot or excessively long adjustment times. Simultaneous adjustments, however, create a synergistic effect, easily causing system oscillations and disrupting temperature field stability. Therefore, a step-by-step, coordinated control approach—first using frequency converters for rapid "coarse adjustment" to bring the temperature back to the set range, then using valve positions for "fine adjustment" to stabilize the operating conditions—maximizes the performance of both actuators, achieving smoother and more precise temperature control.

[0059] Preferably, when performing PID control on the temperature of the rear zone (R and F zones), the processing unit prioritizes adjusting the valve position and then adjusts the fan frequency, thereby achieving energy-saving control while ensuring the stability of the annealing process.

[0060] After annealing, the glass temperature is reduced from 400℃ to 60-70℃. During this period, temporary stress is generated in the glass, which disappears as the glass temperature decreases. The valve positions we are referring to here are the valve positions of the mixed air in zone R and the branch pipe air valve positions in zones R and F. They are still set in an "M" shape. The "M" shape can be adjusted according to the temperature distribution of the glass plate measured on site to reduce the lateral temperature difference between each part (left side - left secondary side - middle - right secondary side - right side). The lateral temperature difference is controlled within ≤5-8℃.

[0061] In temperature control of the rear zone (R and F zones) of float glass annealing furnace, the strategy of prioritizing valve position adjustment and then fan frequency adjustment is more effective because it follows the optimization principle of "fine before coarse, slow before fast" in process control, which can more effectively balance the steady-state control accuracy and energy-saving goals of the system.

[0062] Specifically, valve position adjustments are relatively gradual, altering the local resistance of the air duct. While the impact on airflow has a certain lag, the adjustment process is precise, similar to the "integral (I)" action in PID control, making it suitable for eliminating steady-state residual error and achieving precise temperature control. Changes in fan frequency, however, directly affect motor speed, rapidly and significantly altering airflow and pressure, resulting in a dramatic and rapid impact on temperature, equivalent to the "proportional (P)" action. In the post-annealing zone, the process requires a slow and stable temperature decrease to eliminate permanent stress within the glass, making it extremely sensitive to temperature fluctuations. If the fan frequency is adjusted first or simultaneously, its rapid response can easily trigger system oscillations, leading to temperature overshoot or fluctuations and compromising annealing quality. Therefore, "fine-tuning" of the valve position is used first to maintain temperature stability. Only when valve position adjustment fails to meet the requirements is "coarse-tuning" performed via frequency conversion to change the system's base airflow. This step-by-step, coordinated control method ensures the stability of the annealing process while minimizing fan energy consumption, achieving the dual goals of precise control and energy saving.

[0063] Preferably, the processing unit adopts a differentiated temperature control strategy: based on the process characteristics of different temperature zones in the annealing furnace, a temperature control logic of "prioritizing stable temperature in the front zone and prioritizing energy saving in the rear zone" is proposed to achieve a balance between process stability and energy saving goals.

[0064] The processing unit employs a differentiated temperature control strategy adapted to the characteristics of current float glass processes: the front zone is mainly responsible for controlling the internal stress within the glass body, while the back zone mainly reduces the temperature of the glass sheet to a suitable temperature range for cutting.

[0065] Preferably, a control strategy prioritizing stable temperature in the front zone and energy conservation in the rear zone is adopted because the front zone (zones A, B, and C) and the rear zone (zones F) of the annealing furnace have distinctly different process missions. The front zone, especially zone B, is a critical area where permanent stress is generated in the glass. Its temperature regime directly determines the annealing quality of the glass. Precise and stable temperature control is essential to eliminate internal stress and prevent glass cracking or deformation; therefore, process stability must be prioritized. In contrast, by the time the glass enters the rear zone, the main annealing process has been completed. The core task at this stage is to rapidly and uniformly cool the glass to room temperature for subsequent cutting and handling. The process has a relatively high tolerance for temperature fluctuations. Therefore, the focus of the control logic can shift to energy conservation. By optimizing fan frequency and valve opening, energy consumption can be minimized while ensuring basic cooling effects, thereby achieving the optimal balance between process stability and energy efficiency.

[0066] Preferably, when using the DCS intelligent temperature control system for a float glass annealing furnace according to Embodiment 1 or Embodiment 2 to control the temperature of the annealing furnace, ventilation openings such as windows near the annealing furnace can be opened, the height of the workshop roller shutter door can be adjusted to 2-3 meters per side, and ventilation openings can be opened near the air inlets of zones A, B, and C to introduce outdoor air (for example, by opening 100-150 mm holes in the corrugated steel below the windows corresponding to the air inlets of zones A, B, and C). (Introducing outdoor air at a depth of 100 cm) reduces the temperature of the medium, thereby reducing the frequency of the fan and saving energy.

[0067] Inside the workshop, hot air is lighter and rises, causing air pressure to decrease; cold air is heavier and sinks, causing air pressure to increase. Air flows from high pressure to low pressure, creating wind. When doors and windows are opened, the hot air in the workshop is carried away by the wind, lowering the indoor temperature. A 20°C breeze carries away more heat than a 30°C breeze through the fan, thus reducing the frequency of fan operation.

[0068] Preferably, by actively introducing low-temperature outdoor air through methods such as opening vents for ventilation, controlling the height of the roller shutter door, and opening windows in each area, and combining this with the DCS intelligent temperature control system to control the temperature of the annealing kiln, an energy-saving mode of "passive cooling + active frequency control" can be constructed, achieving deep utilization of natural cold sources, especially in autumn and winter when the ambient temperature is low, resulting in significant energy savings.

[0069] When using the DCS intelligent temperature control system of a float glass annealing furnace according to Embodiment 1 or Embodiment 2 to control the temperature of the annealing furnace, the natural cold source is utilized to establish a "weather-product-process" linkage mechanism. The parameters can be dynamically adjusted according to seasonal changes and differences in glass specifications, covering both routine production and special working conditions.

[0070] Preferably, when the DCS intelligent temperature control system controls the temperature of the annealing furnace, it increases the opening of the ambient temperature mixing air in zone R, decreases the air temperature setpoint in zone Ret2, and lowers the glass plate temperature in zone E. This reduces the operating frequency of the fans in zones Ret and F, achieving energy savings through a dual mechanism of "moving the heat load forward" and "reducing cooling difficulty." First, increasing the opening of the ambient temperature mixing air in zone R utilizes low-cost ambient cold air to replace some of the low-temperature circulating air that requires electrical energy, directly reducing the cold air preparation load in zone Ret2. Second, lowering the air temperature setpoint in zone Ret2 significantly increases the heat exchange temperature difference (heat transfer driving force) between the air and the glass. According to the principles of heat transfer, under the same cooling requirements, a larger temperature difference means a smaller required air volume. These two measures work together to effectively lower the temperature of the glass plate in zone E before it enters zones Ret and F, thus significantly reducing the total amount of heat that needs to be removed by the subsequent forced convection cooling zones (zones Ret and F). Therefore, the fans can operate at a lower frequency to meet the process cooling requirements, ultimately achieving significant energy savings. For example, a high-temperature object has a surface temperature of 400°C. It is cooled to 80°C by using a distance of 10 meters. Two cooling nozzles are set up within the 10-meter distance. The front end uses two different air temperatures, A and B, with A at 150°C and B at 250°C. The rear end uses the same air temperature of 60°C. The former uses the larger cooling gradient (A), which consumes less electricity than the latter, and is therefore more energy-efficient.

[0071] Preferably, when using a DCS intelligent temperature control system to control the temperature of the annealing furnace, the air inlets on the upper and lower plates of zones A, B, and C should be cleaned regularly every 3-4 months to reduce blockage of the pipe openings, reduce airflow resistance in the ducts, and decrease the frequency of fan use. Preferably, regular cleaning of the air inlets reduces pipe blockage, lowers the fan operating load, and extends the service life of the equipment.

[0072] Preferably, during the production of thin plates, the DCS intelligent temperature control system can select an appropriate temperature threshold based on the input process parameters, so that the temperature threshold of zones A and B is higher than that when producing thick plates, thereby reducing the frequency of fan use and achieving energy saving.

[0073] When using the DCS intelligent temperature control system of the float glass annealing furnace described in Example 1 or Example 2 to control the temperature of the annealing furnace, the DCS intelligent temperature control system can significantly reduce the power consumption of the annealing furnace by optimizing the fan operating frequency and utilizing natural cold sources. The energy-saving effect is particularly prominent in autumn and winter, achieving significant energy saving and cost reduction.

[0074] The use of a DCS intelligent temperature control system for a float glass annealing furnace, as described in Example 1 or Example 2, to control the temperature of the annealing furnace promotes the leap from semi-automation to full automation of float glass annealing furnaces, which is in line with the industry's trend of intelligent development.

[0075] When the DCS intelligent temperature control system of a float glass annealing furnace described in Example 1 or Example 2 is used to stabilize the temperature of the annealing furnace, the electricity cost of the glass production process can be reduced, and the profitability of the enterprise can be improved. The temperature control system and differentiated parameter configuration reduce process fluctuations caused by human intervention and ensure the consistency of glass product quality.

[0076] This embodiment demonstrates that the DCS intelligent temperature control system for float glass annealing furnaces provided by this invention offers a replicable technical solution for energy-saving retrofitting of annealing furnaces in the float glass industry, and has high application value.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A DCS intelligent temperature control system for a float glass annealing furnace, characterized in that, include: Input unit, used to set process parameters; The processing unit determines a temperature control scheme based on the process parameters, and controls the operating conditions of the fan drive module and the valve position adjustment module according to the temperature control scheme; wherein, the temperature control scheme includes temperature thresholds for each zone; The fan drive module responds to the control of the processing unit and adjusts the air supply frequency of the fan in the annealing furnace. The valve position adjustment module responds to the control of the processing unit and adjusts the valve position of the air duct in the annealing furnace. The monitoring unit is used to acquire monitoring data; The processing unit also regulates the operating conditions of the fan drive module and the valve position adjustment module based on the monitoring data.

2. The DCS intelligent temperature control system for a float glass annealing furnace according to claim 1, characterized in that, The process parameters include: glass specifications, conveying speed of the annealing furnace, and number of ventilation openings in each zone.

3. The DCS intelligent temperature control system for a float glass annealing furnace according to claim 2, characterized in that, The processing unit is equipped with a database module; the database module pre-stores several temperature control schemes; the processing unit matches a temperature control scheme from the database module according to the specifications of the glass and the conveying speed of the annealing furnace.

4. The DCS intelligent temperature control system for a float glass annealing furnace according to claim 3, characterized in that, The monitoring data includes: ambient temperature and the temperature of each zone inside the annealing furnace.

5. The DCS intelligent temperature control system for a float glass annealing furnace according to claim 4, characterized in that, The processing unit performs PID control on the operating conditions of the fan drive module and the valve position adjustment module based on the monitoring data and the temperature control scheme.

6. The DCS intelligent temperature control system for a float glass annealing furnace according to claim 5, characterized in that, For the front zone of the annealing furnace, the processing unit adjusts the air supply frequency of the fan through the fan drive module to make the temperature reach the temperature threshold.

7. The DCS intelligent temperature control system for a float glass annealing furnace according to claim 6, characterized in that, For the front zone of the annealing furnace, when the air supply frequency of the blower reaches the upper limit of the operating condition and the temperature does not reach the temperature threshold, the processing unit adjusts the valve position of the air duct in the annealing furnace through the valve position adjustment module.

8. The DCS intelligent temperature control system for a float glass annealing furnace according to claim 5, characterized in that, For the rear zone of the annealing furnace, the valve position adjustment module adjusts the valve position of the air duct in the annealing furnace to make the temperature reach the temperature threshold.

9. The DCS intelligent temperature control system for a float glass annealing furnace according to claim 8, characterized in that, In the rear zone of the annealing furnace, when the valve position of the air duct reaches the upper limit of the operating conditions and the temperature does not reach the temperature threshold, the processing unit adjusts the air supply frequency of the fan through the fan drive module.

10. A DCS intelligent temperature control method for a float glass annealing furnace, characterized in that, The temperature of the annealing furnace is controlled by a DCS intelligent temperature control system for a float glass annealing furnace as described in any one of claims 1-9.

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