Sample heating control method and device for detecting sulfur dioxide in medicinal materials

Abstract

The application relates to the technical field of food safety detection, and discloses a sample heating control method and device for detecting sulfur dioxide in food and medicinal materials. The method is based on a heating module and a distillation flask, and a heat-resistant medium is arranged between the heating module and the distillation flask, and the method comprises the following steps: based on a sample detection instruction, the heating power of the heating module is controlled; a part of the distillation flask containing the sample is a first part, and a part of the distillation flask not containing the sample is a second part; the heating module provides first heat energy for the first part, and the first heat energy is used for keeping the temperature of the sample within a preset target temperature range; the heating module provides second heat energy for the second part through the heat-resistant medium, and the second heat energy is used for keeping the temperature of the second part lower than the volatilization temperature value of dilute hydrochloric acid in the sample. Since the volatilization of dilute hydrochloric acid cannot be eliminated by the current technology, the application can eliminate the volatilization of dilute hydrochloric acid, and improve the accuracy of the result of detecting sulfur dioxide in food and medicinal materials.

Description

Technical Field

[0001] This application relates to the technical field of food safety testing, and in particular to a sample heating control method and apparatus for detecting sulfur dioxide in food and medicinal materials. Background Technology

[0002] The detection of sulfur dioxide in food and medicinal materials is crucial for ensuring food safety. During the processing of these materials, some producers use sulfur dioxide or its derivatives for fumigation and bleaching to achieve preservation and color protection. However, if the residue exceeds the standard, it can damage the human respiratory and digestive systems, and long-term ingestion may even lead to chronic poisoning. Therefore, accurately detecting sulfur dioxide residue in food and medicinal materials is a key link in controlling their quality and preventing health risks. It is also an important aspect of food safety supervision and is of great significance for regulating market order and protecting public health.

[0003] Currently, the distillation-titration method is commonly used for the detection of sulfur dioxide in food and medicinal materials. The core step involves heating the sample during distillation to release sulfur dioxide. The national testing standard now recommends a heating method using an electric heating mantle to cover the distillation flask containing the sample. The specific procedure is as follows: the sample to be tested is placed in the distillation flask, diluted hydrochloric acid is added, and the flask is heated by an electric heating device to distill the sulfur dioxide gas to the surface. Nitrogen gas then pushes the sulfur dioxide gas into a condenser, where it condenses the water vapor produced during distillation back into the test tube. The sulfur dioxide is then pushed by the nitrogen gas to a collection container, such as a reaction cup, where it is absorbed by an absorbent solution containing a colorimetric reagent (hydrogen peroxide) and oxidized to sulfuric acid, thus collecting the sulfur dioxide. Finally, the sulfur dioxide content is calculated using a standard alkali titration method. This method has become the mainstream detection method in the industry due to its relatively simple operation and low cost.

[0004] However, in the electric heating mantle method, the heating temperature is difficult to control. The inner wall of the distillation flask in contact with the sample is kept at a temperature of 100°C (at atmospheric pressure) due to the sample's moisture content, operating at a "mild boiling" state. However, the inner wall of the distillation flask not in contact with the sample, directly heated by the electric heating element without sample cooling buffer, will exceed 100°C. Since the sample is distilled with hydrochloric acid, which has a boiling point of 110°C, excessively high temperatures cause hydrochloric acid evaporation, interfering with subsequent acid-base titrations, resulting in inflated detection values, unstable data, and a high risk of misinterpretation. Summary of the Invention

[0005] To improve the accuracy of sulfur dioxide detection results in food and medicinal materials, this application provides a sample heating control method and apparatus for detecting sulfur dioxide in food and medicinal materials.

[0006] In a first aspect, this application provides a sample heating control method for detecting sulfur dioxide in food and medicinal materials, employing the following technical solution: A sample heating control method for detecting sulfur dioxide in food and medicinal materials, based on a heating module and a distillation flask, wherein a heat-insulating medium is provided between the heating module and the distillation flask, comprising the following steps: The heating power of the heating module is controlled based on the sample detection command. The portion of the distillation flask containing the sample is the first portion, and the portion of the distillation flask not containing the sample is the second portion. The heating module provides first thermal energy to the first part, and the first thermal energy is used to keep the temperature of the sample within a preset target temperature range. The heating module provides a second heat energy to the second part through the heat-insulating medium. The second heat energy is used to keep the temperature of the second part below the volatilization temperature of the dilute hydrochloric acid in the sample.

[0007] By employing the above technical solution, the distillation flask is heated in sections using a heat-insulating medium. The heating module provides initial heat energy to the first part containing the sample, precisely controlling the sample temperature within the target range. This ensures that sulfur dioxide in the sample can fully volatilize and escape, effectively improving the extraction efficiency of sulfur dioxide and providing sufficient detection material for subsequent analysis, thus enhancing detection sensitivity. The heating module provides a second layer of heat energy to the second part of the distillation flask, which does not contain the sample, keeping its temperature below the volatilization temperature of dilute hydrochloric acid in the sample, thereby preventing the volatilization of dilute hydrochloric acid. If dilute hydrochloric acid volatilizes, it will mix into the detection system, interfering with the detection results of sulfur dioxide and causing deviations in the detection data. Given that current technology struggles to eliminate the volatilization of dilute hydrochloric acid, this application eliminates the volatilization of dilute hydrochloric acid, thereby significantly improving the accuracy and reliability of sulfur dioxide detection results.

[0008] Optionally, the heat-insulating medium covers a local area in the second part that is in contact with the first part; Alternatively, the heat-resistant medium may cover the entire area of ​​the second portion; Alternatively, the heat-resistant medium may cover the entire area of ​​the second part and the local area of ​​the first part that is in contact with the second part; Alternatively, the heat-resistant medium may cover the entire area of ​​the second part and the entire area of ​​the first part.

[0009] By adopting the above technical solutions, partial coating of the second part in contact with the first part provides precise heat insulation, reduces costs and saves energy, and stabilizes the sample heating temperature. Full coating of the second part ensures comprehensive temperature control and prevents volatilization, guaranteeing accurate detection and stabilizing the temperature field. Coating the area where the second and first parts contact optimizes heat conduction, provides precise temperature control, and improves detection consistency. Full coating of both the first and second parts maintains an overall uniform temperature in a "slight boiling" state, promoting sulfur dioxide release, eliminating hydrochloric acid mist caused by the high temperature of the second part, resisting environmental interference, and enhancing detection reliability.

[0010] Optionally, the method further includes the following steps: The sum of the preset heating offset value and the maximum temperature value within the target temperature range is calculated to be the maximum reference value for boiling point; The boiling point temperature of the heat-insulating medium is less than or equal to the maximum reference boiling point value.

[0011] By adopting the above technical solution, considering the different heat transfer losses caused by varying distillation flask thicknesses, the maximum reference value of the boiling point is calculated based on the heating offset value and the target maximum temperature. This allows for precise selection of the heat-insulating medium, compensation for temperature drop, stable heat transfer, promotion of stable sulfur dioxide release, and improved detection reliability. Limiting the boiling point temperature of the heat-insulating medium prevents boiling-induced heat transfer disturbances, maintains temperature uniformity, avoids the volatilization of hydrochloric acid impurities, and improves detection accuracy.

[0012] Optionally, the method further includes the following steps: Acquire the temperature loss data of the heat-insulating medium transferring heat to the distillation flask, and adjust the heating offset value according to the positive correlation of the temperature loss data; Alternatively, the heating offset value can be set inversely related to the sidewall thickness value of the second part.

[0013] By adopting the above technical solution, the heating power is dynamically increased according to the actual temperature loss, ensuring that the sample temperature in the distillation flask accurately reaches the target range and avoiding detection errors caused by differences in heat transfer efficiency. When changing to heat-resistant media of different materials or states (such as water baths or oil baths), the system can automatically match the corresponding temperature loss characteristics, improving the versatility and stability of the method. Thicker sidewalls naturally hinder heat transfer; adjusting the heating offset value inversely can balance the temperature distribution in areas of different thicknesses, ensuring that the temperature in the second part is strictly lower than the impurity volatilization temperature while maintaining the target temperature in the first part.

[0014] Optionally, the heat-insulating medium includes water, oil, and / or sand.

[0015] By adopting the above technical solutions, water, oil, and / or sand are selected as heat-insulating media, each with its own advantages and can be flexibly combined: water is low in cost, has a large specific heat capacity, can transfer heat uniformly, and is environmentally friendly and safe; oil has a high boiling point and stable heat transfer, making it suitable for high-temperature testing scenarios; sand has good thermal conductivity, high temperature resistance, stable morphology, and can be reused. The three materials, used individually or in combination, can adapt to different testing needs, reduce costs, and ensure testing accuracy and safety.

[0016] Optionally, the heat-insulating medium is further coated with another layer of heat-insulating medium, wherein the boiling point of the outer layer of heat-insulating medium is greater than that of the inner layer of heat-insulating medium, wherein: The outer layer of heat-insulating medium covers part or all of the inner layer of heat-insulating medium; Meanwhile, the outer layer of heat-resistant medium covers the second part, or the outer layer of heat-resistant medium covers both the first part and the second part.

[0017] By adopting the above technical solution, combining two layers of heat-insulating media with different boiling points, and setting up various coating structures, the temperature stability of the first and second parts is further improved.

[0018] Optionally, the method further includes the following steps: One or more temperature sensors are provided in the heat-insulating medium; Temperature data is acquired based on the temperature sensor; The temperature value of the thermal resistance medium is calculated based on the temperature data as the thermal resistance temperature value. Calculate the first difference between the thermal resistance temperature value and the maximum reference value of the boiling point; The heating power of the heating module is adjusted according to the inverse correlation of the first difference.

[0019] By employing the above technical solution and deploying temperature sensors within the heat-resistant medium, real-time temperature data for each region of the medium can be acquired, improving the accuracy of the thermal resistance temperature value. When the thermal resistance temperature approaches the maximum reference value of the boiling point, the system automatically reduces the heating power to prevent the heat-resistant medium from boiling and affecting heat transfer efficiency; if the temperature is too low, the power is appropriately increased to compensate for heat loss.

[0020] Optionally, the method further includes the following steps: Based on the fact that the heat-insulating medium covers a portion, rather than the entire portion, of the second part, the liquid level height data of the sample in the distillation flask is obtained; The highest value is calculated from the liquid level height data; The coating area of ​​the heat-insulating medium on the second part is adjusted according to the highest value.

[0021] By adopting the above technical solution, the coating area of ​​the heat-insulating medium in the second part of the distillation flask can be dynamically adjusted according to the highest value of the sample liquid level, thus dynamically adapting to the actual distribution of the sample.

[0022] Secondly, this application provides a sample heating control device for detecting sulfur dioxide in food and medicinal materials, which adopts the following technical solution: A sample heating control device for detecting sulfur dioxide in food and medicinal materials includes a processor, wherein the processor executes the steps of the sample heating control method for detecting sulfur dioxide in food and medicinal materials as described in any one of the above claims.

[0023] In summary, this application includes at least one of the following beneficial technical effects: By using a heat-resistant medium for zoned heating, the temperature of the sample area is precisely controlled to fully release sulfur dioxide, while simultaneously suppressing the volatilization of impurities in the non-sample area, thereby improving detection sensitivity and accuracy; strategies such as employing multiple heat-resistant medium coating methods, dynamically adjusting heating offset values, and using a double-layer heat-resistant medium structure optimize heat conduction, enhance the system's adaptability to different equipment and samples, and reduce errors caused by heat transfer loss or medium boiling; deploying a temperature sensor in the heat-resistant medium establishes a real-time feedback adjustment mechanism for stable temperature control; and further improving temperature control flexibility and detection stability through dynamic adjustment methods such as sample liquid level height and weighted boiling point of the mixed medium. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the steps of a sample heating control method for detecting sulfur dioxide in food and medicinal materials.

[0025] Figure 2 This is a schematic diagram of the heat-insulating medium coating structure used for heating via a water bath.

[0026] Figure 3 This is a schematic cross-sectional view of the first type of coating structure for heat-insulating media.

[0027] Figure 4 This is a schematic cross-sectional view of the second type of coating structure for heat-insulating media.

[0028] Figure 5 This is a schematic cross-sectional view of the third type of coating structure for heat-insulating media.

[0029] Figure 6 This is a schematic cross-sectional view of the fourth type of coating structure for heat-insulating media.

[0030] Figure 7 This is a schematic cross-sectional view of the first type of structure with an outer layer of heat-insulating medium.

[0031] Figure 8 This is a schematic cross-sectional view of the second type of structure with an outer layer of heat-insulating medium.

[0032] Reference numerals: 1. Distillation flask; 2. Heat-insulating medium; 3. Part 1; 4. Part 2. Detailed Implementation

[0033] The embodiments of this application are described in detail below, and examples of the embodiments are shown in the accompanying drawings.

[0034] In the description of this specification, the references to "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" refer to specific features, structures, materials, or characteristics described in connection with the described embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0035] This application discloses a sample heating control method for detecting sulfur dioxide in food and medicinal materials, referring to... Figure 1 and Figure 2 Based on the heating module and the distillation flask 1, a heat-insulating medium 2 (water, oil, and / or sand) is provided between the heating module and the distillation flask 1, including the following steps: Upon receiving a sample testing command, the heating module is activated, and its heating power is precisely controlled according to preset parameters. The distillation flask 1 is divided into two key areas: the portion containing the sample is defined as part 3, the bottom of distillation flask 1; the sample liquid contains sulfur dioxide, which is released upon heating; the portion not containing the sample is part 4, the upper part of distillation flask 1 not in contact with the sample liquid, and its temperature is controlled to prevent impurities from volatilizing and interfering with the detection. The sample liquid mainly consists of water, dilute hydrochloric acid, and sulfur dioxide; the impurity here refers to dilute hydrochloric acid, with an evaporation temperature of 110℃.

[0036] The heating module provides initial heat energy to the first part 3, and through continuous monitoring and feedback adjustment, ensures that the sample temperature remains stable within the preset target temperature range, which is 99.5-109℃. Within this temperature range, sulfur dioxide in the food and medicinal materials can volatilize and escape with optimal efficiency.

[0037] The heating module transfers the second heat energy to the second part 4 through the heat-insulating medium 2. The heat-insulating medium 2 plays a dual role in this process: firstly, it acts as a heat transfer medium; secondly, through its own thermal buffering properties, it controls the temperature of the second part 4 below the volatilization temperature of the dilute hydrochloric acid in the sample. This temperature is higher than the target temperature range but lower than the volatilization temperature of the dilute hydrochloric acid in the sample, effectively preventing the dilute hydrochloric acid from volatilizing and mixing into the detection system, thus preventing it from interfering with the sulfur dioxide detection results and greatly improving the accuracy and reliability of the detection data.

[0038] The heating module provides a second heat energy to the second part 4 through the heat-insulating medium 2. The second heat energy is used to keep the temperature of the second part 4 below the volatilization temperature of the dilute hydrochloric acid in the sample. The volatilization temperature of the dilute hydrochloric acid in the sample is greater than any temperature value within the target temperature range.

[0039] The heating module delivers differentiated heat energy to different areas of the distillation flask 1 using the heat-insulating medium 2: For the first part 3 containing the sample, the first heat energy is precisely supplied, and the temperature is strictly controlled within the preset target range, which promotes the full volatilization of sulfur dioxide from the sample and significantly improves the extraction efficiency; For the second part 4 not containing the sample, the second heat energy is transferred through the heat-insulating medium 2. Under its thermal buffering effect, the temperature in this area is limited to below the volatilization temperature of dilute hydrochloric acid in the sample, effectively avoiding the volatilization of dilute hydrochloric acid in the sample and preventing it from entering the detection system and interfering with the determination of sulfur dioxide, thereby strongly ensuring the accuracy and reliability of the detection results and ensuring that the detection data truly reflects the sulfur dioxide content of food and medicinal materials.

[0040] Regarding the selection of the heat-insulating medium 2, this solution offers a multi-combination scheme of water, oil, and / or sand. Each medium possesses unique physicochemical properties and can be flexibly combined to adapt to different testing requirements. Water-based media: Due to its low cost, high specific heat capacity, and environmental safety, water has become the preferred choice for basic testing scenarios. Water can evenly absorb and transfer heat during the heating process, ensuring that all parts of the distillation flask are heated evenly. It is especially suitable for temperature-sensitive food and medicinal samples, avoiding local overheating that could damage the components.

[0041] Oil-based media: With a high boiling point and stable heat transfer properties, they are particularly suitable for special scenarios requiring high-temperature detection. For example, when detecting certain food and medicinal materials containing high-boiling-point impurities, oil-based media can maintain liquid stability within a higher temperature range, continuously providing the required heat energy to the sample, while not boiling or decomposing itself, ensuring the stability and safety of the detection process.

[0042] Sand-based media stand out due to their excellent thermal conductivity, high-temperature resistance, and stable physical state. Sand particles can rapidly transfer heat and are not prone to chemical changes or loss during repeated use, reducing the cost of experimental consumables. At the same time, the solid nature of sand-based media allows it to fit tightly against the outer wall of the distillation flask, forming an efficient heat conduction channel, which is especially suitable for precision detection with extremely high requirements for temperature uniformity.

[0043] In this embodiment, the coating structure of the heat-insulating medium 2 has the following multiple forms: The first type: Reference Figure 3 The heat-insulating medium 2 covers the local area in the second part 4 that is in contact with the first part 3; it can be precisely applied to key parts that are prone to heat conduction, effectively blocking the high temperature of the first part 3 from spreading to the second part 4, while reducing the amount of heat-insulating medium 2 used, reducing energy consumption and cost; at the same time, it avoids too much additional impact on the heating of the sample in the first part 3, ensuring that the temperature of the sample area is stable within the target range, and maintaining the efficient release of sulfur dioxide.

[0044] The second method: Reference Figure 4 The heat-insulating medium 2 covers the entire area of ​​the second part 4; it can protect the second part 4 in all directions and more stably control its temperature below the preset volatilization temperature of dilute hydrochloric acid in the sample, preventing the volatilization of dilute hydrochloric acid in the sample and ensuring that the detection results are not interfered with by impurities to the greatest extent; moreover, the uniform coating helps to maintain the uniform temperature field of the second part 4 and prevent local overheating from damaging the distillation flask 1 or causing safety hazards.

[0045] The third type: Reference Figure 5 The heat-insulating medium 2 covers the entire area of ​​the second part 4 and the local area of ​​the first part 3 that is in contact with the second part 4; it can take into account the key areas of both parts, ensuring that the temperature of the second part 4 is controlled, and further optimizing the heat transfer management at the junction of the two parts, reducing abnormal heat conduction from the first part 3 to the second part 4; at the same time, it can fine-tune the temperature of the edge area of ​​the first part 3, avoid temperature unevenness caused by edge heat dissipation, improve the accuracy and stability of the temperature control of the entire distillation flask 1, and ensure the accuracy and consistency of sulfur dioxide detection.

[0046] The fourth type: reference Figure 6 The heat-insulating medium 2 covers the entire area of ​​the second part 4 and the entire area of ​​the first part 3. This enables comprehensive temperature control of the distillation flask 1. Through the buffering effect of the heat-insulating medium 2, the temperature distribution throughout the distillation flask 1 becomes more uniform, effectively avoiding the impact of excessive local temperature differences on the sample and the detection process. It not only ensures the temperature safety of the second part 4, but also, through the homogenizing effect of the medium, allows the sample in the first part 3 to be heated more evenly, promoting a more complete and stable release of sulfur dioxide. Simultaneously, it significantly reduces the interference of the external environment on the temperature of the distillation flask 1, significantly improving the reliability of the detection process and the accuracy of the detection results.

[0047] Taking into account the heat transfer loss caused by the thickness of distillation flask 1, the method also includes the following steps: Based on the preset heating offset value of 1℃ and the maximum temperature value within the target temperature range (e.g., 109℃), the sum is calculated to be the maximum reference value for boiling point (109℃ + 1℃ = 110℃). This ensures that the heat-insulating medium 2 can effectively compensate for the temperature drop during heat conduction while maintaining stable liquid heat transfer, avoiding the blockage of heat transfer due to boiling and vaporization of the medium. This ensures that the sample temperature in the distillation flask 1 is stably maintained within the target range, guaranteeing the full and continuous release of sulfur dioxide.

[0048] The boiling point of heat-insulating medium 2 is less than or equal to the maximum reference boiling point value of 110℃. Limiting the boiling point of heat-insulating medium 2 to within the maximum reference boiling point value can effectively avoid heat transfer disturbances caused by the boiling of the medium.

[0049] Based on the heat transfer loss caused by the thickness of distillation flask 1, the maximum reference value of boiling point is calculated by pre-setting the heating offset value and the maximum value of the target temperature, providing a precise standard for the selection of heat-insulating medium 2. This can compensate for the temperature drop, maintain stable liquid heat transfer, ensure that the sample temperature is within the target range to promote the full release of sulfur dioxide, and improve detection sensitivity and reliability.

[0050] Considering the heat loss issue in practical applications, the method for dynamically adjusting the heating offset value also includes the following steps: Method 1: Temperature loss data of the heat transfer from the heat-insulating medium 2 to the distillation flask 1 is obtained through a temperature sensor. The heating offset value is adjusted according to the positive correlation of the temperature loss data. When the monitored medium temperature is 110℃, the outer wall temperature of the distillation flask 1 is only 108℃, resulting in a 2℃ loss. According to the positive correlation adjustment rule, the heating offset value is synchronously increased from the preset 1℃ to 3℃ (the offset value increases by 1℃ for every 1℃ increase in loss). This dynamic calibration of the offset value adjusts the maximum reference value of the boiling point from 110℃ (109+1) to 118℃ (108+3), thereby driving the heating module power to achieve precise adjustment.

[0051] Method 2: The heating offset value is set inversely to the sidewall thickness value in Part 2, Section 4. In actual testing scenarios, the difference in the thickness of the distillation flask 1 will significantly change the heat conduction path and efficiency. Taking a common glass distillation flask 1 as an example, the heat conduction loss of a container with a wall thickness of 1 mm can differ by 15%-20% compared to a container with a wall thickness of 3 mm.

[0052] When the wall thickness is 2mm, the offset value is set to 4℃, and heat is added to make the temperature reach the standard. Taking a sidewall thickness of 3mm as an example, the offset value is set to 3℃, so that the temperature in this area is stably maintained at 107℃ (110-3), which is lower than the critical temperature of 110℃ for impurity volatilization. When the wall thickness increases to 4mm, the offset value automatically drops to 2℃ to prevent the temperature from exceeding the standard due to overcompensation in the thick-walled area.

[0053] By dynamically adjusting the heating power based on real-time collected temperature loss data, the temperature deviation caused by differences in heat transfer efficiency can be accurately compensated, ensuring that the sample temperature in distillation flask 1 is strictly maintained within the target range, thus avoiding detection errors at the source.

[0054] In other embodiments, the heat-insulating medium 2 is further covered by another layer of heat-insulating medium 2, and the boiling point of the outer layer of heat-insulating medium 2 is greater than that of the inner layer of heat-insulating medium 2.

[0055] The combination of an outer high-boiling-point medium (such as silicone oil, boiling point 150-300℃) and an inner low-boiling-point medium (such as water, boiling point 100℃) forms a temperature buffer structure. When the outer medium covers the first part 3, the high boiling point characteristic allows it to transfer higher heat (such as 110-120℃), while the inner medium absorbs excess heat through the latent heat of vaporization (2260J of heat is absorbed by each gram of water evaporation), preventing the temperature of the sample area from exceeding 109℃. If the outer medium covers the second part 4, its high thermal stability can block the intrusion of external heat (thermal conductivity is only 0.13W / m・K), and in conjunction with the heat dissipation effect of the inner medium, the temperature of the second part 4 can be more strictly kept below 110℃.

[0056] The vapor layer (with high thermal resistance) generated when the inner medium boils complements the continuous heat transfer of the outer liquid medium. For example, in a water-silicone oil bilayer system, the water vaporizes and absorbs heat when the temperature reaches 100°C, while the silicone oil maintains a heat transfer temperature of 110°C, thus improving the temperature control accuracy compared to a single-layer oil bath.

[0057] In addition, the following structures are available for the outer heat-insulating medium 2: The first type: Reference Figure 7 The outer layer of heat-insulating medium 2 covers the second part 4, focusing on strengthening the temperature protection of the second part 4, which does not contain the sample, in the distillation flask 1. The outer high-boiling-point heat-insulating medium 2 forms a robust heat insulation barrier, greatly reducing the conduction of external heat into the interior. Combined with the heat dissipation function of the inner low-boiling-point heat-insulating medium 2, the temperature of the second part 4 can be firmly controlled below the impurity volatilization temperature threshold, avoiding interference from the volatilization of dilute hydrochloric acid with the detection results.

[0058] The second method: Reference Figure 8 The outer heat-insulating medium 2 simultaneously covers both the first part 3 and the second part 4. The outer heat-insulating medium 2 covers the first part 3; this all-round covering method enables in-depth control of the overall temperature of the distillation flask 1. The outer heat-insulating medium 2 constructs an overall insulation framework to reduce heat loss, while the inner heat-insulating medium 2 is precisely adjusted according to the temperature requirements of different areas, making the temperature distribution inside the distillation flask 1 more uniform and stable.

[0059] To improve the accuracy of temperature data detection, the method also includes the following steps: One or more temperature sensors are installed in the heat-insulating medium 2; for example, 3-5 temperature sensors are deployed in the heat-insulating medium 2.

[0060] Temperature data is acquired based on temperature sensors; the temperature value of the thermal resistance medium is calculated using a weighted average algorithm based on the temperature data, which is the thermal resistance temperature value.

[0061] Calculate the first difference between the thermal resistance temperature value and the maximum reference value of the boiling point; adjust the heating power of the heating module according to the inverse correlation of the first difference.

[0062] Adjusted heating power = initial heating power + K0 × first difference; where K0 is a negative adjustment coefficient, in W / ℃.

[0063] Temperature sensors are installed within the heat-insulating medium 2 to collect real-time temperature data for each area, effectively improving the accuracy of thermal resistance temperature measurement. When the thermal resistance temperature approaches the maximum reference boiling point, the system automatically reduces the heating power to prevent the heat-insulating medium 2 from boiling and affecting heat transfer efficiency; conversely, when the temperature is too low, the system appropriately increases the power to compensate for heat loss.

[0064] In the detection of sulfur dioxide in food and medicinal materials, the liquid level in distillation flask 1 significantly affects heat conduction and temperature distribution during heating, thus interfering with the accuracy of the detection results. To reduce the degree of interference, a dynamic liquid level response method is adopted, which includes the following steps: Based on the fact that the heat-insulating medium 2 covers a portion, rather than the entire, area of ​​the second part 4, the liquid level height data of the sample in the distillation flask 1 is obtained. The liquid level height data is obtained using a laser rangefinder sensor or other non-contact liquid level monitoring device.

[0065] The maximum value is calculated from the liquid level height data; the coating area of ​​the heat-insulating medium 2 on the second part 4 is adjusted according to the maximum value.

[0066] When the liquid level is high, expanding the coverage area can more effectively block heat conduction to the area above the distillation flask 1 that does not contain the sample, ensuring that the temperature of the second part 4 remains stable below 110℃. This prevents the volatilization of dilute hydrochloric acid in the sample and avoids its interference with the sulfur dioxide detection results, thereby improving the accuracy and reliability of the detection. Conversely, when the liquid level is low, appropriately reducing the coverage area ensures effective temperature control while avoiding energy waste caused by overheating.

[0067] The specific dynamic adjustment strategy is as follows: In low liquid level scenarios (liquid level height < 1 / 3 of the height of distillation flask 1): the system determines this as a low-risk area and automatically reduces the coverage area of ​​the heat-insulating medium 2 to the lower 1 / 3 of the second part 4. At this time, the heat-insulating medium 2 only protects critical parts that may be affected by heat conduction. While maintaining the temperature of the second part 4 below 110°C, the amount of medium used is reduced, energy consumption is lowered, and energy waste caused by overheating is avoided.

[0068] In the mid-liquid-level scenario (distillation flask 1 height 1 / 3 ≤ liquid level < 2 / 3): The system activates the standard coating mode, covering the middle area of ​​the second part 4 with the heat-insulating medium 2. This area corresponds precisely to the height range that the sample may reach when boiling. Through precise temperature control, heat is prevented from diffusing upwards, ensuring that the temperature fluctuation of the second part 4 is controlled within ±1℃, significantly reducing the risk of impurity volatilization.

[0069] In high liquid level scenarios (liquid level height ≥ 2 / 3 of the height of distillation flask 1): The system triggers a full-area coverage strategy, covering the entire area of ​​the second part 4 with the heat-insulating medium 2, extending upwards to the bottleneck. On the one hand, this significantly enhances temperature control in the upper space, reducing the intensity of liquid boiling through uniform heat dissipation and decreasing the probability of liquid splashing; on the other hand, by strengthening thermal barrier, it ensures that the temperature of the second part 4 is stably maintained below 108℃, blocking the escape path of volatile impurities in the sample and improving the accuracy of the detection results.

[0070] This application also discloses a sample heating control device for detecting sulfur dioxide in food and medicinal materials, including a processor, wherein the processor executes the steps of the sample heating control method for detecting sulfur dioxide in food and medicinal materials as described in any of the above embodiments.

[0071] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for controlling sample heating in the detection of sulfur dioxide in food and medicinal materials, characterized in that, Based on the heating module and the distillation flask (1), a heat-insulating medium (2) is provided between the heating module and the distillation flask (1), including the following steps: The heating power of the heating module is controlled based on the sample detection command. The portion of the distillation flask (1) containing the sample is the first part (3), and the portion of the distillation flask (1) not containing the sample is the second part (4). The heating module provides first thermal energy to the first part (3), and the first thermal energy is used to keep the temperature of the sample within a preset target temperature range; The heating module provides a second heat energy to the second part (4) through the heat-insulating medium (2), and the second heat energy is used to keep the temperature of the second part (4) lower than the volatilization temperature of the dilute hydrochloric acid in the sample; The heat-insulating medium (2) covers the local area in the second part (4) that is in contact with the first part (3); Alternatively, the heat-insulating medium (2) may cover the entire area of ​​the second part (4); Alternatively, the heat-insulating medium (2) covers the entire area of ​​the second part (4) and the local area of ​​the first part (3) that is in contact with the second part (4); Alternatively, the heat-resistant medium (2) may cover the entire area of ​​the second part (4) and the entire area of ​​the first part (3).

2. The sample heating control method for detecting sulfur dioxide in food and medicinal materials according to claim 1, characterized in that, The method also includes the following steps: The sum of the preset heating offset value and the maximum temperature value within the target temperature range is calculated to be the maximum reference value for boiling point; The boiling point temperature of the heat-resistant medium (2) is less than or equal to the maximum reference value of the boiling point.

3. The sample heating control method for detecting sulfur dioxide in food and medicinal materials according to claim 2, characterized in that, The method also includes the following steps: Obtain the temperature loss data of the heat-insulating medium (2) transferring heat to the distillation flask (1), and adjust the heating offset value according to the positive correlation of the temperature loss data; Alternatively, the heating offset value can be set inversely related to the sidewall thickness value of the second part (4).

4. The sample heating control method for detecting sulfur dioxide in food and medicinal materials according to claim 1, characterized in that, The heat-insulating medium (2) includes water, oil and / or sand.

5. The sample heating control method for detecting sulfur dioxide in food and medicinal materials according to claim 1, characterized in that, The heat-insulating medium (2) is further coated with another layer of the heat-insulating medium (2), wherein the boiling point of the outer layer of the heat-insulating medium (2) is greater than that of the inner layer of the heat-insulating medium (2), wherein: The outer layer of heat-insulating medium (2) covers part or all of the inner layer of heat-insulating medium (2); Meanwhile, the outer heat-insulating medium (2) covers the second part (4), or the outer heat-insulating medium (2) covers both the first part (3) and the second part (4).

6. The sample heating control method for detecting sulfur dioxide in food and medicinal materials according to claim 2, characterized in that, The method also includes the following steps: One or more temperature sensors are provided in the heat-insulating medium (2); Temperature data is acquired based on the temperature sensor; The temperature value of the heat-resistant medium (2) is calculated based on the temperature data as the thermal resistance temperature value; Calculate the first difference between the thermal resistance temperature value and the maximum reference value of the boiling point; The heating power of the heating module is adjusted according to the inverse correlation of the first difference.

7. The sample heating control method for detecting sulfur dioxide in food and medicinal materials according to claim 1, characterized in that, The method also includes the following steps: Based on the fact that the heat-insulating medium (2) covers part of the second part (4) but not all of it, the liquid level height data of the sample in the distillation flask (1) is obtained; The highest value is calculated from the liquid level height data; The coating area of ​​the heat-insulating medium (2) on the second part (4) is adjusted according to the highest value.

8. A sample heating control device for detecting sulfur dioxide in food and medicinal materials, characterized in that, The device includes a processor that performs the steps of the sample heating control method for detecting sulfur dioxide in food and medicinal materials as described in any one of claims 1-7.

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