Tobacco leaf baking dry-wet linkage system operation method

Abstract

The invention discloses a tobacco leaf curing dry-wet linkage system operation method, which comprises the following steps of: after a tobacco leaf curing process curve is set, entering a curing temperature and humidity automatic control mode, and when abnormal temperature drop is caused by fuel supply interruption or heat supply equipment failure and the like in a curing barn, starting an automatic control mode; and according to the difference value between the set target dry-bulb temperature and the actually measured dry-bulb temperature, the decreasing amplitude of the target wet-bulb temperature is obtained through calculation, and therefore the dynamic target wet-bulb temperature is obtained through calculation, and dry-wet linkage in the tobacco leaf curing process is achieved. The problems that humidity control lags behind, the adjusting precision is low and tobacco leaves are prone to being damaged during abnormal temperature drop of existing tobacco leaf curing temperature are solved, dynamic and accurate adjustment of the wet bulb temperature in the abnormal temperature drop scene is achieved, the moisture removal effect and tobacco leaf protection are both considered, and the curing quality is improved.

Description

Technical Field

[0001] This invention relates to the field of tobacco curing equipment control technology, and in particular to a system operation method for tobacco curing with dry and wet linkage when abnormal curing temperature occurs. Background Technology

[0002] Tobacco curing is a crucial step in determining tobacco quality, with precise temperature and humidity control directly impacting yellowing, color fixation, and drying. Currently, tobacco curing primarily employs a three-stage curing process (GB / T 23219—2008) for local operation. By inputting parameters for each stage into the tobacco curing controller, a curing process curve can be generated. After setup, the controller automatically controls the heating and dehumidification equipment to ensure that the measured dry-bulb and wet-bulb temperatures within the curing barn remain approximately at the set target temperatures. Under normal circumstances, this application fully meets the needs of tobacco curing and conditioning.

[0003] However, during the actual curing process, abnormal temperature drops often occur due to factors such as fuel supply interruption, heating equipment failure, and extreme weather. The measured dry-bulb temperature will be significantly lower than the target dry-bulb temperature, and the measured wet-bulb temperature will not reach the set target wet-bulb humidity value. In other words, the dehumidification function is completely ineffective, which manifests as a rapid increase in relative humidity in the curing barn. If the wet-bulb temperature control strategy is not adjusted in time, it will lead to quality problems such as water droplets condensing on the surface of the tobacco leaves, mottled leaves, and ash accumulation, which will seriously reduce the proportion of high-grade tobacco.

[0004] Among the existing tobacco curing temperature and humidity control technologies, some solutions can only achieve stable control of normal temperature and humidity, lacking specific responses to abnormal temperature drop scenarios; some technologies adjust wet-bulb temperature by preset fixed process curves, which cannot adapt to dynamic scenarios with different temperature drop ranges, and no safety protection mechanism is set up, which can easily cause cold shock damage to tobacco leaves due to sudden drop in dry-bulb temperature.

[0005] On August 16, 2023, the applicant filed a patent application for a system operation method in case of abnormal temperature during tobacco curing, application publication number CN 116880631 A. This application discloses "an abnormal temperature curing backup module and a curing process threshold curve added to the automatic tobacco curing controller. During each stage of curing, if the measured dry-bulb temperature exceeds the temperature of the curing process threshold curve, the abnormal temperature curing backup module is triggered. The abnormal temperature curing backup module includes a database of relative humidity values ​​βn for each stage of tobacco curing. The module first obtains the measured dry-bulb temperature value, then calculates the wet-bulb / dry-bulb difference e using the measured dry-bulb temperature value and the actual relative humidity value βn for that stage. Finally, by subtracting the wet-bulb / dry-bulb difference e from the measured dry-bulb temperature value, the current target wet-bulb temperature is obtained. This allows the automatic tobacco curing controller to control the dehumidification motor in the curing barn to dehumidify. This invention can effectively avoid the situation where abnormal conditions during tobacco curing cause a significant drop in temperature in the curing barn, leading to tobacco leaf damage." The applicant has tested this technology in the past two years. This technology can utilize βn values ​​at different stages... While the data adapts to a certain range of temperature drops and has a threshold triggering mechanism, which can prevent abnormal temperature drops from damaging tobacco leaves to some extent, there are still significant shortcomings. The main issue is that the core parameter "calculating the wet-dry difference e by converting the measured dry-bulb temperature value with the actual relative humidity value βn at that stage" is not accurate enough. When the node temperature is not reached, the calculation of the target wet-bulb temperature relies on the preset actual relative humidity value βn at that stage, which leads to inaccurate wet-bulb temperature regulation and an inability to respond in real time to dynamic changes in the temperature drop. Moreover, the linked target wet-bulb temperature decreases as the measured dry-bulb temperature decreases, forming a cycle of cooling, dehumidification, dehumidification, and cooling, causing the dry-bulb temperature in the curing barn to drop rapidly, thus affecting the quality of the cured tobacco. If the relative humidity value βn of the real-time curve is added, a larger database will be required, making the existing tobacco curing controller incompatible and resulting in high update costs.

[0006] Therefore, there is an urgent need for a dry-wet linkage operation method that can dynamically respond to abnormal temperature drops, accurately adjust wet-bulb temperature, and ensure safety, in order to solve the above-mentioned technical pain points. Summary of the Invention

[0007] In view of this, the present invention aims to solve the problems of lagging humidity control, low adjustment accuracy, and easy damage to tobacco leaves when the existing tobacco curing temperature drops abnormally. It provides a system operation method for tobacco curing with dry and wet linkage, which realizes dynamic and precise adjustment of wet bulb temperature under abnormal temperature drop scenarios, takes into account both dehumidification effect and tobacco leaf protection, and improves curing quality.

[0008] This invention is achieved through the following technical solution: The system operation method for combined dry and wet tobacco curing includes the following steps: 1) Determine the target dry bulb temperature T, the corresponding target wet bulb temperature H, and the time for each baking stage, and set the tobacco baking process curve data in the tobacco baking controller; 2) Set the activation parameters for the dry-wet linkage algorithm in the tobacco curing controller, including the activation minimum dry-bulb temperature threshold t' and the activation minimum temperature difference et, et>0; when the stage target dry-bulb temperature T>t' and the difference between the target dry-bulb temperature T and the measured dry-bulb temperature t satisfies Tt>et, the dry-wet linkage algorithm function is triggered. 3) After the triggering condition in step 2) is met, calculate the decrease in the target wet-bulb temperature. The calculation formula is: = (Target dry-bulb temperature T - Measured dry-bulb temperature t) / 2; 4) Based on the calculation results of step 3), calculate the initial target wet-bulb temperature H0 = stage target wet-bulb temperature H - target wet-bulb temperature decrease rate. ; 5) Correct the initial target wet-bulb temperature H0: If the measured dry-bulb temperature t - the initial target wet-bulb temperature H0 ≥ 2℃, then the final target wet-bulb temperature H' = the initial target wet-bulb temperature H0; if the measured dry-bulb temperature t - the initial target wet-bulb temperature H0 < 2℃, then the final target wet-bulb temperature H' = the measured dry-bulb temperature t - 2℃.

[0009] The aforementioned system operation method for the dry and wet linkage of tobacco curing is as follows: in step 2), the minimum dry-bulb temperature threshold t' and the minimum temperature difference et are both stored in the flash storage module of the dense curing barn controller and are automatically read and loaded when the equipment is powered on.

[0010] The aforementioned system operation method for the dry-wet linkage of tobacco curing is as follows: when the measured dry-bulb temperature t in the curing barn is greater than or equal to the target dry-bulb temperature T, the dry-wet linkage algorithm function is disabled, and the humidity is still adjusted based on the preset target wet-bulb temperature H.

[0011] The aforementioned system operation method for the dry and wet linkage of tobacco curing is that the dry and wet linkage algorithm is integrated into the temperature and humidity control logic of the tobacco curing controller. The tobacco curing controller cyclically detects the dry bulb temperature and wet bulb temperature data and automatically performs calculation and control operations.

[0012] The aforementioned system operation method for the dry-wet linkage of tobacco curing involves the automatic updating of the target dry-bulb temperature T and target wet-bulb temperature H as the tobacco curing process curve switches between stages, with the dry-wet linkage algorithm synchronously adapting to calculate the parameters of the corresponding stage.

[0013] The aforementioned system operation method for the dry and wet linkage of tobacco curing is as follows: after the triggering condition in step 2) is met, the tobacco curing controller enters the specific curing chamber damper opening setting. The specific curing chamber damper opening is set to 2 / 5 of the curing chamber damper opening size. After the humidity slowly decreases by 3-5℃, the dehumidification control is then carried out according to the conventional control rules.

[0014] The beneficial effects of this invention are: 1. Strong dynamic adaptability: This invention dynamically calculates the wet-bulb temperature adjustment range by the difference between the target dry-bulb temperature and the measured dry-bulb temperature. It does not rely on a preset humidity database and can adapt to various temperature drop scenarios caused by different reasons such as fuel supply interruption and equipment failure. It has higher adjustment accuracy and more real-time response.

[0015] 2. High safety: The 2℃ safety threshold correction mechanism and specific opening of the curing barn damper effectively avoid cold shock to tobacco leaves caused by a sudden drop in wet bulb temperature, while preventing drastic temperature and humidity fluctuations caused by excessively rapid dehumidification, thus significantly reducing tobacco leaf curing losses.

[0016] 3. High degree of automation: The algorithm is integrated into the curing barn controller to realize full automation of anomaly detection, parameter calculation and execution control, reducing reliance on manual operation, and is especially suitable for scenarios with dense curing barns in remote areas and centralized management of multiple curing barns.

[0017] 4. Strong compatibility: It can be directly integrated into existing dense curing barn controllers without the need for additional hardware. Parameters can be customized to adapt to the needs of different varieties of tobacco leaves at different curing stages, and the cost of promotion and application is low.

[0018] Compared with the "System Operation Method under Abnormal Temperature in Tobacco Curing" (application publication number CN 116880631 A) (hereinafter referred to as the prior application), it has significant advantages in terms of control logic, adaptability, security, and execution accuracy. The specific comparison is as follows: (I) The core logic of the prior application is based on a preset relative humidity βn database. The wet-dry difference e is obtained through the conversion relationship between humidity and temperature, and then the target wet-bulb temperature is deduced. The process is as follows: "Step 2: The abnormal temperature baking backup module includes a baking process threshold curve. This curve is for dry-bulb temperature and is parallel to the tobacco baking process curve, with a temperature difference of 3℃. When the measured dry-bulb temperature in the curing barn exceeds the baking process threshold curve, the abnormal temperature baking backup module function is activated; Step 3: After activating the abnormal temperature baking backup module function, the abnormal temperature baking backup module first reads the measured dry-bulb temperature in the current curing barn and the target relative humidity value βn corresponding to this stage during normal baking, and calculates the corresponding wet-dry difference e. Step 4: Subtract the wet-dry difference e calculated in Step 3 from the measured dry-bulb temperature in the current curing barn to obtain the current target wet-bulb temperature." Step 5: Then, the dehumidification motor on the curing barn is controlled by the automatic tobacco controller to dehumidify to the target wet-bulb temperature. Looking at the calculation method of the key "dry-wet difference e" in step 3, it's easy to see that this process relies too heavily on the "target relative humidity value βn corresponding to this stage," leading to inaccurate temperature control at each stage of temperature change. For example, in the third step of the yellowing period in the three-stage seven-step method (dry-bulb temperature 42, wet-bulb temperature 34, relative humidity value βn 57), if a temperature drop occurs, the exhaust vent opening will be further increased to maintain the relative humidity value βn 57, further lowering the curing barn temperature. This causes premature dehydration of the tobacco leaves, affecting their quality. This is more pronounced in the higher-temperature color fixing and drying stages. Therefore, relying on fixed humidity data for calculation cannot respond in real-time to dynamic changes in the temperature drop (such as rapid temperature drops caused by fuel supply interruption and slow temperature drops caused by equipment aging, poor insulation, air leakage, etc.), resulting in poor adjustability.

[0019] This application dynamically calculates the wet-bulb temperature adjustment range based on the difference between the target dry-bulb temperature T and the measured dry-bulb temperature t. It does not rely on any preset humidity database. By setting the minimum activation dry-bulb temperature threshold t' and the minimum activation temperature difference et, it achieves precise triggering of temperature drop scenarios, avoiding false triggering of the algorithm under over-temperature or normal temperature conditions. At the same time, the stage target temperature and humidity parameters are automatically updated with the baking process curve, which can adapt to temperature drop scenarios in various stages such as yellowing, color setting, and drying stages. Moreover, it does not rely on preset environmental data and can operate stably in various complex baking oven environments, with superior targeting and reliability in scenario adaptation.

[0020] (ii) The application previously set an abnormal trigger threshold for “the measured dry bulb temperature exceeds the process threshold curve”, and it can be adapted to different temperature drop ranges through the βn database. However, it only mentioned controlling the dehumidification motor after obtaining the target wet bulb temperature through conversion, without setting any safety threshold for parameter correction or graded protection mechanism: there is no safety threshold for wet bulb temperature adjustment, which can easily lead to a sudden drop in wet bulb temperature due to the conversion error of dry-wet difference e, causing cold shock to tobacco leaves; there is also no graded control strategy for dehumidification equipment, which can easily lead to drastic fluctuations in temperature and humidity in the curing barn due to excessive dehumidification, causing damage such as tobacco leaf breakage and ash accumulation. Its threshold is only used to trigger abnormalities and cannot achieve safety protection for subsequent control.

[0021] This application constructs a dual safety protection mechanism: First, a 2℃ safety threshold correction mechanism is set up. When the difference between the measured dry-bulb temperature t and the initial target wet-bulb temperature H0 is less than 2℃, H'=t-2℃ is automatically corrected to avoid cold shock to tobacco leaves caused by excessively low wet-bulb temperature. Second, a graded opening control of the cold air damper is adopted. It is set to level 2 (out of a total of 5 levels) during the initial linkage dehumidification. After the humidity gradually decreases by 3-5℃, it switches to normal control to avoid temperature and humidity fluctuations caused by excessively rapid dehumidification, significantly improve the safety of curing, and reduce the loss rate of tobacco leaves.

[0022] (iii) Prior applications are highly dependent on hardware and data: On the one hand, a large-capacity storage module needs to be integrated into the controller to store the βn database. In the renovation of old baking rooms, the storage and computing power of the controller are limited, making it difficult to promote.

[0023] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will now be described in further detail with reference to the accompanying drawings, wherein: Figure 1 This is a process flow diagram of the present invention; Figure 2 The time-temperature curves for the three-stage, seven-step tobacco roasting method are shown. Detailed Implementation

[0025] The following will refer to the appendix Figure 1 The preferred embodiments of the present invention will be described in detail below. It should be understood that the preferred embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0026] Example 1: A system operation method for combined dry and wet tobacco curing, specifically including the following steps: Step 1: Set up the tobacco curing process curve data and determine the target dry bulb temperature T and target wet bulb temperature H for each stage of curing; Data on tobacco curing process curves, such as Figure 2 As shown, the baking operation in the local area is carried out according to the three-stage baking process (GB / T 23219—2008), specifically as follows: Yellowing stage: After ignition, maintain a low flame to raise the temperature of the curing barn to 35-36℃, keeping the wet-bulb temperature at 34.5-35.5℃. Once the leaf tips and edges turn yellow, increase the dry-bulb temperature to 38℃ at a rate of 1℃ per hour, maintaining this temperature for an extended period, controlling the wet-bulb temperature at 36-37℃. This will ensure that approximately 80% of the tobacco leaves in the curing barn, measured by the thermometer, reach 70-80% yellowing, while simultaneously softening (with a water loss of approximately 30%). Then, raise the temperature to 42℃, maintaining the wet-bulb temperature at 37℃ for an extended period, until the tobacco leaves are yellow with slightly green veins, wilting and collapsing, and the midrib softens.

[0027] Color fixation period: The dry-bulb temperature is first increased at an average rate of 1°C every 2 hours to 45°C and then maintained for a longer period to allow the tobacco leaves to curl at the tips and edges. Then, the temperature is increased at an average rate of 1°C every 2 hours to 48°C and maintained for a longer period to allow the tobacco veins to turn yellow and lose moisture to achieve small leaf curling. Afterward, the temperature is increased again at a rate of 1°C every 2 hours to 55°C and maintained for 10 hours to achieve complete leaf drying. As the dry-bulb temperature rises, the wet-bulb temperature gradually increases and stabilizes at 39°C.

[0028] Drying stage: Increase the temperature from 55℃ to 68℃ at a rate of 1℃ per hour and maintain it until the tobacco leaves are completely dry. Before the dry bulb temperature reaches 60℃, maintain the wet bulb temperature at 40℃; after reaching 60℃, maintain the wet bulb temperature at 40~42℃.

[0029] Step 2: Set the minimum dry-bulb temperature t' and the minimum temperature difference et (et must be greater than 0) for the dry-wet linkage algorithm. When the target dry-bulb temperature is greater than the set threshold t', and the target dry-bulb temperature T - measured dry-bulb temperature t > et, the dry-wet linkage algorithm function is activated. The minimum dry-bulb temperature threshold t' and the minimum temperature difference et are both stored in the flash memory module of the intensive drying oven controller. When the device is powered on, it automatically reads and loads the target dry-bulb temperature parameters for the dry-wet linkage function in the intensive drying oven controller.

[0030] After setting the threshold et for the difference between the measured dry-bulb temperature and the target dry-bulb temperature in the drying oven, the dry-bulb linkage algorithm function is activated when the measured dry-bulb temperature t in the drying oven is lower than the target dry-bulb temperature corresponding to the current stage at this threshold et.

[0031] Step 3: Once the conditions set in Step 2) are met, calculate the magnitude of the decrease in the target wet-bulb temperature. = (Target dry-bulb temperature T - Measured dry-bulb temperature t) / 2. Specifically, when the measured dry-bulb temperature in the drying oven meets the conditions set in step 2, the dense drying oven controller cyclically checks whether the current target dry-bulb temperature is greater than the target dry-bulb temperature value activated by the dry-wet linkage algorithm in step 2. If it is greater, the controller cyclically checks whether the difference between the current measured dry-bulb temperature and the target dry-bulb temperature (the current measured dry-bulb temperature must be less than the target dry-bulb temperature) is greater than or equal to the threshold et of the difference between the measured dry-bulb temperature and the target dry-bulb temperature set in step 2. If it is greater than or equal to the threshold et, the target wet-bulb temperature decrease value is calculated. = (Target dry-bulb temperature - Measured dry-bulb temperature) / 2.

[0032] Step 4: Calculate the initial target wet-bulb temperature H0 = stage target wet-bulb temperature H - the magnitude of the decrease in target wet-bulb temperature. .

[0033] Step 5: Correct the initial target wet-bulb temperature H0: If the measured dry-bulb temperature t - the initial target wet-bulb temperature H0 ≥ 2℃, then the final target wet-bulb temperature H' = the initial target wet-bulb temperature H0; if the measured dry-bulb temperature t - the initial target wet-bulb temperature H0 < 2℃, then the final target wet-bulb temperature H' = the measured dry-bulb temperature t - 2℃.

[0034] If the current measured dry-bulb temperature is greater than or equal to the set target dry-bulb temperature for the corresponding stage, the target wet-bulb temperature will remain the set target wet-bulb temperature for the corresponding stage, and no dry-wet linkage calculation is required.

[0035] Once the target wet-bulb temperature is obtained, the intensive curing barn controller controls the opening of the cold air supply damper based on the measured wet-bulb temperature and the target wet-bulb temperature h to perform dehumidification. To prevent a sudden drop in the target wet-bulb temperature below 2°C, which could cause a cold shock to the tobacco leaves, the cold air damper is initially opened at level 2. After the humidity slowly decreases by 3-5°C, dehumidification control is then performed according to the standard cold air damper control rules.

[0036] Example 2, conventional temperature drop This embodiment addresses a scenario where slow temperature drop occurs due to insufficient fuel supply during the tobacco curing and color-fixing period (target dry-bulb temperature T=45℃, target wet-bulb temperature H=38℃). The specific implementation process is as follows: 1. Preset color-changing process parameters: T=45℃, H=38℃; Configure activation parameters: minimum dry-bulb temperature t'=35℃ for dry-wet linkage algorithm activation, minimum temperature difference et=2℃ for dry-wet linkage algorithm activation; 2. The drying oven controller monitors the temperature in real time. When the measured dry-bulb temperature t=42℃, Tt=3℃>et=2℃, and T=45℃>t'=35℃, the dry-wet linkage algorithm is triggered. 3. Calculate the decrease in target wet-bulb temperature. = (Target dry-bulb temperature T - Measured dry-bulb temperature t) / 2 = (45 - 42) / 2 = 1.5℃; 4. Initial target wet-bulb temperature H0 = Stage target wet-bulb temperature H - Amount of decrease in target wet-bulb temperature =38-1.5=36.5℃; 5. Correction judgment: The measured dry-bulb temperature t - the initial target wet-bulb temperature H0 = 42 - 36.5 = 5.5℃ ≥ 2℃, therefore the final target wet-bulb temperature H' = 36.5℃; 6. The controller detects that the actual wet-bulb temperature is 39℃. Based on the difference between the final target wet-bulb temperature H' and the actual wet-bulb temperature, the controller controls the initial opening of the cold air supply damper to level 2 to continuously remove moisture. After 30 minutes, the actual wet-bulb temperature drops to 36.5℃, and the damper switches to the normal control mode to maintain stable temperature and humidity.

[0037] In this embodiment, by using dry and wet linkage control, the humidity increase caused by temperature drop was avoided, and the tobacco leaves did not show mottled leaves or ash accumulation. The proportion of high-grade tobacco after curing was increased by 4.79% compared with conventional control methods.

[0038] Example 3, Rapid Temperature Drop Scenario This embodiment addresses a scenario of rapid temperature drop due to a circulating fan malfunction during the yellowing stage of tobacco leaf curing (target dry-bulb temperature T=38℃, target wet-bulb temperature H=36℃). The specific implementation process and actual temperature data are as follows: 1. Preset yellowing period process parameters: T=38℃, H=36℃; Configure activation parameters: minimum dry bulb temperature t'=35℃ for dry-wet linkage algorithm activation, minimum temperature difference et=2℃ for dry-wet linkage algorithm activation; The controller detects temperature and humidity data at a cycle of 10 seconds. 2. Initial state (0min): The measured dry bulb temperature t=38℃ and the measured wet bulb temperature=36℃. Both temperature and humidity meet the target requirements. The dry and wet linkage algorithm is not activated. The cold air damper is operating at the normal opening level 1. 3. Abnormal Trigger (1 min): The circulating fan malfunction caused the temperature to drop rapidly. The measured dry bulb temperature t=35.5℃, Tt=38-35.5=2.5℃>et=2℃, and T=38℃>t'=35℃, triggering the dry and wet linkage algorithm; 4. Parameter Calculation and Correction (1 min 10 s): Calculate the rate of decrease in the target wet-bulb temperature. = (Target dry-bulb temperature T - Measured dry-bulb temperature t) / 2 = (38 - 35.5) / 2 = 1.25℃; Initial target wet-bulb temperature H0 = Stage target wet-bulb temperature H - Target wet-bulb temperature decrease magnitude =36-1.25=34.75℃; Corrected judgment: Measured dry-bulb temperature t - initial target wet-bulb temperature H0 = 35.5 - 34.75 = 0.75℃ < 2℃. Therefore, the final target wet-bulb temperature H' after correction is equal to the measured dry-bulb temperature t - 2℃ = 35.5 - 2 = 33.5℃; 5. Dehumidification Control (1 min 20 s - 5 min): Measured wet-bulb temperature = 36.2℃. The controller adjusts the cold air damper opening to level 2 to begin staged dehumidification. Real-time temperature data during this period is as follows: - 2 min: t = 36.3℃, measured wet-bulb temperature = 35.8℃; - 3 min: t = 36.2℃, measured wet-bulb temperature = 35.0℃; - 4 min: t = 36.1℃, measured wet-bulb temperature = 34.4℃; - 5min: t=36.0℃, measured wet-bulb temperature=33.5℃, reaching the final target wet-bulb temperature H'; 6. Mode switching (after 5 minutes): The cold air damper opening is switched to the normal control mode (dynamic adjustment from level 1 to 5), maintaining the measured wet bulb temperature stable between 34.5-35℃; at the same time, the controller triggers a heating equipment fault alarm to remind staff to perform maintenance. 7. Baking effect: Before troubleshooting (lasting about 2 hours), the temperature and humidity in the curing barn were kept stable through dry and wet linkage control, and the tobacco leaves turned yellow evenly without condensation, mottled leaves, or other problems. After troubleshooting, the system automatically restored to the normal process parameters during the yellowing period. In the end, the curing loss of the tobacco leaves in this oven was only 5.2%, which was significantly better than the control group that did not use this method (curing loss of 10.8%).

[0039] The dry-wet linkage algorithm of this invention can be integrated into the firmware of the intensive drying oven controller via C language programming. The controller uses an STM32F103 chip as the main control unit, paired with a DS18B20 temperature sensor to collect dry-bulb and wet-bulb temperature data, and controls the opening of the cold air supply damper through a relay module. In practical applications, process curve parameters and activation threshold parameters can be set via the drying oven controller's touchscreen or mobile APP, and temperature and humidity data and algorithm operation status can be viewed in real time, facilitating on-site management and remote monitoring.

[0040] This invention is not only applicable to intensive curing barns, but also adaptable to various tobacco curing equipment such as semi-intensive curing barns and intelligent curing barns. It is especially suitable for scenarios where fuel supply is unstable, extreme weather is frequent, and abnormal temperature drops are likely to occur in remote areas, and has broad application value.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A system operation method for combined dry and wet curing of tobacco leaves, characterized in that, Includes the following steps: 1) Determine the target dry bulb temperature T, the corresponding target wet bulb temperature H, and the time for each baking stage, and set the tobacco baking process curve data in the tobacco baking controller; 2) Set the activation parameters for the dry-wet linkage algorithm in the tobacco curing controller, including the activation minimum dry-bulb temperature threshold t' and the activation minimum temperature difference et, et>0; when the stage target dry-bulb temperature T>t' and the difference between the target dry-bulb temperature T and the measured dry-bulb temperature t satisfies Tt>et, the dry-wet linkage algorithm function is triggered. 3) After the triggering condition in step 2) is met, calculate the decrease in the target wet-bulb temperature. The calculation formula is: = (Target dry-bulb temperature T - Measured dry-bulb temperature t) / 2; 4) Based on the calculation results of step 3), calculate the initial target wet-bulb temperature H0 = stage target wet-bulb temperature H - target wet-bulb temperature decrease rate. ; 5) Correct the initial target wet-bulb temperature H0. If the measured dry-bulb temperature t - the initial target wet-bulb temperature H0 ≥ 2℃, then the final target wet-bulb temperature H' = the initial target wet-bulb temperature H0; if the measured dry-bulb temperature t - the initial target wet-bulb temperature H0 < 2℃, then the final target wet-bulb temperature H' = the measured dry-bulb temperature t - 2℃.

2. The system operation method for combined dry and wet tobacco curing according to claim 1, characterized in that: In step 2), the minimum dry-bulb temperature threshold t' and the minimum temperature difference et are both stored in the flash memory module of the intensive drying oven controller and are automatically read and loaded when the device is powered on.

3. The system operation method for combined dry and wet tobacco curing according to claim 1, characterized in that: When the measured dry-bulb temperature t in the drying oven is greater than or equal to the target dry-bulb temperature T for the current stage, the dry-wet linkage algorithm function is disabled, and the humidity is still adjusted based on the preset target wet-bulb temperature H for the corresponding stage.

4. The system operation method for combined dry and wet tobacco curing according to claim 1, characterized in that: The dry-wet linkage algorithm is integrated into the temperature and humidity control logic of the tobacco curing controller. The tobacco curing controller cyclically detects dry-bulb temperature and wet-bulb temperature data and automatically performs calculation and control operations.

5. The system operation method for combined dry and wet tobacco curing according to claim 1, characterized in that: The target dry-bulb temperature T and target wet-bulb temperature H are automatically updated as the tobacco curing process curve switches stages, and the dry-wet linkage algorithm synchronously adapts to calculate the parameters of the corresponding stages.

6. The system operation method for combined dry and wet tobacco curing according to claim 1, characterized in that: After the triggering condition in step 2) is met, the tobacco curing controller enters the specific curing chamber damper opening setting. The specific curing chamber damper opening is set to 2 / 5 of the curing chamber damper opening size. After the humidity slowly decreases by 3-5℃, the dehumidification control is then carried out according to the conventional control rules.

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