Air bath temperature control device and method

Abstract

The invention provides an air bath temperature control device and method for solving the problems existing in an existing temperature control technology. The device comprises a backflow cavity, a static pressure cavity and an air bath cavity which are all provided with heat preservation layers. The backflow cavity is provided with an inner circulation fan, a refrigeration module, a heating module, an outer circulation scavenging port, an outer circulation scavenging air valve and related parts. The air bath cavity is provided with a second temperature sensor and an internal circulation scavenging port; the static pressure cavity is provided with a temperature sensor, an equal-air-volume air supply duct, a flow guide plate and a flow diffusion plate. The three chambers are connected in pairs through the inner circulation air inlet, the flow dispersing plate and the inner circulation air exchange port to form an air circulation channel. And the real-time temperature in the cavity is obtained by calculating the monitoring values of the plurality of temperature sensors through a data fusion strategy. According to the control method, different temperature control strategies are operated according to the difference value between the real-time temperature of the air bath cavity and the external temperature and the difference value between the real-time temperature of the air bath cavity and the target temperature. The method has the effects of high temperature control uniformity and reliability, high efficiency, energy conservation, accurate temperature control and the like.

Description

Technical Field

[0001] The present invention relates to the field of temperature control, and particularly to an air bath temperature control device and method. Background Art

[0002] In many fields such as scientific experiments, industrial production, and medical treatment, precise temperature control is a key factor to ensure the accuracy of experimental results, the stability of product quality, and the normal operation of equipment. There are many deficiencies in the existing temperature control methods. For example, the traditional water bath temperature control method is limited by the properties of water, which may have an adverse impact on some samples or equipment that react with water. Moreover, in some occasions where rapid heating or cooling and high requirements for temperature uniformity are needed, the water bath temperature control is difficult to meet the requirements. Compared with the traditional heating method, air bath constant temperature has advantages such as better temperature uniformity, avoiding sample contamination, and the ability of rapid temperature change, and is more indispensable in the field of temperature control.

[0003] However, some air bath temperature control devices have problems such as low temperature control accuracy, large temperature fluctuations, low heating or cooling efficiency, and excessive energy consumption, and cannot achieve precise and stable temperature control. The invention patent CN112327605B discloses a temperature control system and method for a constant temperature device, which controls the temperature through the cooperation of a refrigeration system, a primary heater and a secondary heater, and the circulation and mixing of air by a blower. However, the device structure and temperature control logic are complex. When using the traditional pid (proportional-integral-derivative) control algorithm for high-precision adjustment in the secondary control, the temperature control is unstable, and there will be a certain degree of interference between the primary control and the secondary control, affecting the response speed and efficiency of temperature control. The gas flow in the gas circuit is unstable due to the control of the throttle valve, and the temperature uniformity cannot be guaranteed. The invention patent CN115562388B discloses a multi-mode composite and active air bath ultra-precision temperature control device, which realizes high-precision and high-efficiency control of the temperature of the inner environment of the sealed box through the composite control of multiple heat transfer methods and reasonable isolation and decoupling measures. However, in order to achieve the purpose of isolation and decoupling among its various components, the structure is relatively complex, it is difficult for the temperature sensor to monitor its true value, and the combined operation of multiple components increases the operation cost, and the control logic is complex and difficult to be actually applied to various working conditions. The Chinese invention patent application CN114063671A discloses a constant temperature control device and method for a CT data acquisition system, which uses multiple temperature sensors to monitor the real-time temperature, and sets weights according to the distance between each temperature sensor and the acquisition point, and takes the weighted average value of all temperature sensors as the real-time temperature of the acquisition point. However, it does not judge whether the monitoring values of the temperature sensors are accurate, and directly takes the weighted average as the real-time temperature value, and cannot eliminate the influence of abnormal temperature values. Summary of the Invention

[0004] Based on this, it is necessary to provide an air bath temperature control device and method for the above problems.

[0005] The air bath temperature control device of the present invention includes: a reflux chamber, a static pressure chamber, and an air bath chamber. Heat insulation layers are provided in all three chambers. The heat insulation layer uses high-efficiency heat insulation materials, which can effectively reduce the influence of the external environmental temperature on the device, ensure the minimization of temperature fluctuations, and improve energy use efficiency.

[0006] The reflux chamber includes an internal circulation fan, a refrigeration module, a heating module, an external circulation ventilation opening, and an external circulation ventilation valve. The internal circulation fan, as the power component for gas transportation, has an adjustable rotation speed and can be intelligently adjusted according to different air volume requirements of the static pressure chamber to ensure the stable flow of gas in the system and provide sufficient power support for temperature control; the refrigeration module includes a heat conduction copper plate, a refrigeration chip, a radiator, and a cooling fan, which are used to cool and regulate the gas; the refrigeration chip is arranged on the side wall of the reflux chamber and is the main refrigeration element. It achieves the refrigeration effect by absorbing heat based on the thermoelectric effect. Its non-working surface is exposed outside the reflux chamber, which is conducive to heat dissipation; the heat conduction copper plate is closely attached to the working surface of the refrigeration chip and has a certain thickness and gaps, which can increase the contact area with air, thereby enhancing the heat transfer performance and heat exchange efficiency, making the refrigeration effect of the refrigeration chip better transferred to the regulated gas to achieve a better refrigeration effect; the radiator is used to absorb the heat on the non-working surface of the refrigeration chip, and the cooling fan speeds up the heat exchange and transfer speed to ensure that the refrigeration chip can work continuously and stably, maintaining the low temperature state of the regulated gas; the heating module includes an electric heating wire or other heating elements, which are used to heat the regulated gas; the electric heating wire or other heating elements are arranged on the side wall of the reflux chamber and heat the regulated gas by dissipating heat, providing another adjustment method for temperature control and meeting different temperature control requirements; the external circulation ventilation opening is used to realize the air exchange and heat transfer between the device of the present invention and the external environment; the external circulation ventilation valve is arranged on the external circulation ventilation opening and is used to control the degree of air exchange and heat transfer, and adjust the influence of the outside on the internal temperature of the device according to the actual temperature situation.

[0007] The air bath chamber includes a suspension support plate and a second temperature sensor; adjustable-sized holes are provided on the suspension support plate for stably placing the reactor, so that the main part of the reactor is immersed in the stable temperature environment of the air bath chamber, and at the same time, it is in close contact with the reactor to form a closed space in the air bath chamber, reducing the influence of the external environment on the temperature in the air bath chamber; there are multiple second temperature sensors, which are arranged near the internal circulation ventilation opening to monitor the temperature in the air bath chamber in real time. The real-time temperature of the air flow out of the air bath chamber is obtained through the multi-temperature sensor data fusion strategy, and the real-time temperature in the air bath chamber is obtained by weighted calculation with the real-time temperature of the air flow into the air bath chamber, making the temperature monitoring more accurate and providing a reliable basis for temperature control.

[0008] The static pressure chamber includes a first temperature sensor, an equal-air-volume supply air duct, a flow deflector, and a diffuser plate. As a buffer chamber, it converts dynamic pressure into static pressure, making the temperature of the regulated gas more uniform and the pressure more stable, thus providing a uniform and stable air bath environment for the air bath chamber. There are multiple first temperature sensors, evenly arranged near the diffuser plate, to monitor the temperature of the regulated gas near the diffuser plate in real time. The real-time temperature of the gas entering the air bath chamber is obtained through a multi-temperature sensor data fusion strategy, and the real-time temperature in the air bath chamber is obtained by weighted calculation with the real-time temperature of the air flowing out of the air bath chamber, making the temperature control more accurate and providing a reliable basis for temperature control. By setting the equal-air-volume supply air duct, the flow deflector, and the diffuser plate, the function of stably regulating the air flow is achieved.

[0009] The air inlet of the equal-air-volume supply air duct is connected to the inner circulation air inlet. There are multiple air outlets facing the air bath chamber. The shape of the air outlet is at least one of rectangle, trapezoid, circle, triangle, sector, ellipse or a regular shape composed of multiple small air outlets of the above shapes. At the same time, the corners can be rounded to reduce the turbulence of the air flow at the air outlet, reduce noise and improve the ventilation efficiency. The opening size of the air outlet gradually increases along the axial direction starting from the air inlet. The opening area S(x) of the air outlet at the axial distance x from the air inlet satisfies the linear relationship S(x)=kx + b (where k and b are constants determined according to the overall parameters of the air duct, the required air volume, etc.). As the distance from the air inlet increases, the area of the air outlet gradually increases. Through this design of gradually changing area, the pressure loss and velocity change of the air flow during the flow in the pipeline are compensated. The distance between the air outlets gradually decreases along the axial direction starting from the air inlet to ensure that the air flows blown out from adjacent air outlets can be connected to each other and cover evenly, avoiding the occurrence of ventilation blind areas. By setting the shape, size, and distance of the air outlets of the equal-air-volume supply air duct, it can be ensured that the air output volume of each air outlet per unit time is equal.

[0010] The flow deflector is arranged in the static pressure chamber and can effectively cover the air flow range of the air outlet of the equal-air-volume supply air duct to reduce the turbulence and noise generated when the air flow passes through the edge. The flow deflector is divided into multiple sections, which are louver plates or perforated plates, effectively reducing the air flow velocity and guiding the air flow direction. Each section of the flow deflector can independently adjust the deflection angle and adaptively adjust the deflection angle according to the deviation between the temperature values monitored by each temperature sensor, realizing multi-dimensional adjustment of the air flow direction, increasing the intersection and mixing of the air flow in different regions, and promoting the temperature uniformity.

[0011] The diffuser plate is a perforated plate with a certain thickness or a flow equalizing plate with flow deflectors. If it is a perforated plate, the hole shapes can be circular, regular hexagonal, triangular or any combination of these shapes. The holes and the gaps between the holes are relatively small, so that the air flow is fully subdivided and evenly dispersed when passing through the holes. The perforated plate has a certain thickness, which can fix the air flow direction and make the air flow form a uniform wind pressure after passing through the diffuser plate. If it is a flow equalizing plate with flow deflectors, the flow deflectors are designed in an arc shape or a multi-fold line shape, etc., to achieve a gentle turning and mixing effect on the air flow. The directions of the flow deflectors are arranged in a staggered pattern according to a certain rule on the surface of the diffuser plate, and the angle between the flow deflectors and the diffuser plate is between 30° and 45°, so that the air flow can be fully mixed and form a uniform wind pressure.

[0012] The inner circulation air inlet is arranged on the connection surface between the return cavity and the static pressure cavity. By means of a stepped connection with the inner circulation fan, the air flow direction is adjusted to make the gas flow into the equal air volume supply air duct stably, reducing gas turbulence. The inner circulation air exchange port is arranged on the connection surface between the air bath cavity and the return cavity and is located on the side wall of the air bath cavity, realizing the stable circulation of gas from the air bath cavity to the return cavity, the inner circulation of gas in the device, and heat exchange.

[0013] The relationship between the range of gas temperature change in the device of the present invention and the required power is as follows, , where P max is the power required for temperature change, ρ is the gas density, V is the gas volume, C P is the specific heat capacity of air, ΔT is the maximum difference between the target temperature and the real-time temperature, and t is the gas circulation time.

[0014] The present invention also provides a control method based on the above air bath temperature control device, including: (1) Complete the installation of each component and check whether the working state is normal; (2) Set the target temperature T 目标 ; (3) Divide different regions in the static pressure cavity and the air bath cavity, and respectively set one or more first temperature sensors and second temperature sensors in each of the divided regions. By cross-verifying the temperature data monitored by different temperature sensors in the same region, and then calculating the average value as the temperature data of the region by using the reliable temperature data among them, and then calculating the real-time temperature as the monitored temperature in the air bath cavity by calculating the temperature and its weight of different regions. The multi-temperature sensor data fusion strategy of the monitored temperature in the air bath cavity is as follows, ① Calculate the deviation between multiple temperature sensors in the same region: , where D mnis the deviation value between different temperature sensors, T m and T n are the monitored temperature values of the m-th and n-th temperature sensors respectively.

[0015] ② Define the allowable range of deviation between temperature sensors in the same area: , where Dev(m, n) is the temperature value deviation between two sensors, T m and T n are the monitored temperature values of the m-th and n-th temperature sensors respectively.

[0016] If D mn ≤ Dev(m, n), then D mn is within the allowable range; If D mn > Dev(m, n), then D mn is outside the allowable range; If D mn is missing, it shall be processed as being outside the allowable range.

[0017] ③ Calculate the temperature value of this area: If D mn are all within the allowable range, then take the average value of all temperature sensors in this area as the result; If D mn are not all within the allowable range, then judge the sensors with deviations outside the range one by one. If there are a deviations outside the range in the deviation set involved by this sensor, where a is a constant greater than half of the number of sensors, then exclude it from this temperature calculation and take the average value of the remaining temperature sensors as the result, which can effectively eliminate the interference of abnormal temperature points and improve the accuracy of data; ④ Calculate the temperature value of the air bath cavity through the temperature values of different areas: Determine the temperature weight of the monitored area through the natural attenuation change gradient of the temperature of the air flow along the flow direction in the device, and then perform operations based on the temperature and its weight of the monitored area in the air bath cavity to obtain the real-time temperature in the air bath cavity.

[0018] where T 气浴腔 is the real-time temperature of the air bath cavity, N is the number of temperature monitoring areas, W m is the weight of the m-th temperature monitoring area, and T m is the temperature value of the m-th temperature monitoring area.

[0019] (4)According to the obtained real-time temperature T 静压 of the static pressure cavity and the external temperature T环境 The real-time temperature T of the air bath chamber 气浴 and the target temperature T 目标 relationship, and the difference e(k) between T 目标 and T 气浴 are jointly used to select an appropriate temperature control strategy.

[0020] According to the preset temperature error E for entering the fuzzy PID control algorithm max and the preset temperature error E for entering the PID strategy library min ; ① When e(k) < -E max and T 环境 < T 静压 , or e(k) > E max and T 环境 > T 静压 , simultaneously open the external circulation ventilation valve and the internal circulation fan connected to the outside of the reflux chamber. The internal circulation fan operates at full power to exchange the air inside the chamber with the outside air until |e(k)| < E max or |T 环境 - T 静压 | < t °C (t is a constant and can be set), then immediately close the external circulation ventilation valve; ② When e(k) < -E max and T 环境 > T 静压 , both the thermoelectric cooler and the internal circulation fan operate at full power to quickly cool the temperature of the gas inside the chamber; ③ When e(k) > E max and T 环境 < T 静压 , both the heating wire and the internal circulation fan operate at full power to quickly increase the temperature of the gas inside the chamber; ④ When -E min > e(k) > -E max , the operating power P of the thermoelectric cooler 制冷片 is controlled by the fuzzy PID algorithm. The internal circulation fan blows the cold air into the static pressure box to achieve uniform gas temperature and reduced flow rate, and then slowly spreads it into the air bath chamber through the diffuser plate to reduce the chamber temperature. At the same time, the gas flows back to the reflux chamber through the internal circulation ventilation port to realize the internal circulation of the gas in the air bath temperature control device; ⑤ When E max > e(k) > E min , the operating power P of the heating wire 电热丝It is controlled by a fuzzy PID algorithm. The inner loop fan blows hot air into the static pressure box to achieve uniform gas temperature and decreased flow velocity. Then it is slowly dispersed into the air bath cavity through the diffuser plate to increase the cavity temperature. At the same time, the gas flows back to the reflux cavity through the inner loop ventilation opening to realize the regulation of the inner loop of the gas in the air bath temperature control device; ⑥When 0 > e(k) > -E min At this time, the power P of the Peltier cooler 制冷片 is finely controlled by the fuzzy PID strategy library. At this time, P 制冷片 is maintained at a low level to maintain the stability of the temperature inside the cavity and avoid temperature overshoot at the same time; ⑦When E min > e(k) > 0, the power P of the heating wire 电热丝 is finely controlled by the fuzzy PID strategy library. At this time, P 电热丝 is maintained at a low level to maintain the stability of the temperature inside the cavity and avoid temperature overshoot at the same time; The air temperature inside the device has a delay. From the moment when the temperature inside the device is detected to be less than the target value until the heater starts to heat, the temperature inside the device will continue to decrease for a period of time. When the heating stops, the temperature will not stop rising immediately but will rise for a period of time before stopping. The temperature inside the device has been fluctuating up and down. The fuzzy adaptive PID algorithm can solve such problems well. The differential control component can improve the dynamic characteristics of the system, and the integral control component can reduce the static error of the system. The model is as follows.

[0021] In the formula, K p 、K i 、K d are the proportional coefficient, integral coefficient, and differential coefficient of the fuzzy PID respectively, which are optimized in real time by fuzzy logic according to certain fuzzy rules. e(k) is the real-time error value, and e(k - 1) is the previous error value. Quantized input: The fuzzy algorithm needs to quantize the input quantity. Taking the error value and the error change rate as the input quantities, they are projected to a certain digital level through the quantization function, which will affect the calculation accuracy.

[0022] Calculate the membership degree: Establish the fuzzy subsets of the input quantities, and calculate their respective corresponding membership degrees according to the quantization results of the error value and the error change rate.

[0023] Establish the respective fuzzy rule bases of K p 、K i 、K d : The selection of the K p value determines the response speed of the system. In the initial stage of regulation, it is necessary to rapidly increase the temperature of the regulated gas in the system, and a relatively large K should be appropriately selected.p value to improve the response speed. In the middle stage of regulation, K p takes a smaller value to make the system have a smaller probability of temperature overshoot and ensure a certain response speed. Then, in the later stage of the regulation process, K p is adjusted to a larger value to reduce the temperature static error and improve the temperature control accuracy; K i is mainly used to eliminate the steady-state deviation of the system temperature. In the initial stage of regulation, the temperature of the regulated gas in the system needs to rise rapidly without overshooting. K i should be selected as a smaller value or even zero to prevent integral saturation. In the middle stage of regulation, K i should be appropriately increased to a moderate value to reduce the steady-state error and avoid affecting stability. In the later stage of the regulation process, K i should be selected as a larger value to reduce the regulation static error and ensure that the temperature is near the target value; K d mainly lies in changing the dynamic characteristics of the system. In the initial stage of regulation, the temperature of the regulated gas in the system needs to rise rapidly without overshooting. K d should be selected as a larger value to suppress or even avoid overshooting. In the middle stage of regulation, K d value should be appropriately smaller and kept constant; in the later stage of regulation, K d value should be reduced to weaken the braking effect of the controlled process, thereby compensating for the extended temperature regulation time caused by the larger K d value in the initial stage of the regulation process.

[0024] Fuzzy inference and defuzzification: For the temperature error value and the error change rate, the "center of gravity method" can be used to find the output value and its corresponding membership degree according to the fuzzy rule base of K p 、K i 、K d 。

[0025] Clear quantization result: Multiply the output value by its corresponding membership degree to obtain the solution of the K p 、K i 、K d output value. Convert and correct this solution to obtain K p 、K i 、K d for PID control.

[0026] When the device of the present invention is operating, the internal air flow circulation process is as follows. The regulated gas is affected by the refrigeration and heating modules in the reflux chamber, and the temperature is adjusted through the refrigeration module or the heating module. Under the action of the internal circulation fan, the regulated gas flows inside the device, enters the static pressure chamber through the internal circulation air inlet, converts the dynamic pressure into static pressure in the static pressure chamber, and the regulated gas uniformly and stably passes through the equal air volume air supply duct. Under the action of the deflector, the flow velocity decreases, and it is fully mixed in the static pressure chamber to achieve uniform and stable temperature. Then, it stably flows into the air bath chamber through the diffuser plate, forms a stable temperature field in the air bath chamber, and the gas flows back to the reflux chamber through the internal circulation air exchange port, forming a closed circulation system.

[0027] Specific links: Refrigeration or heating process: When it is necessary to reduce the temperature of the air bath chamber, the refrigeration module is started, the refrigeration chip works, the heat-conducting copper plate transfers the heat to the radiator, and the cooling fan accelerates the heat dissipation to cool the regulated gas. When it is necessary to increase the temperature of the air bath chamber, the heating wire of the heating module generates heat to heat the regulated gas.

[0028] Function of the static pressure chamber: Under the action of the equal air volume air supply duct, the regulated gas uniformly enters the static pressure chamber. Under the action of the deflector, the flow direction is changed, the travel is increased, and it is fully mixed to make the temperature distribution more uniform. Subsequently, the gas passes through the diffuser plate to uniformly disperse the gas, reduce the pressure fluctuation, and ensure that the gas enters the air bath chamber in a stable state.

[0029] Air bath chamber circulation: The gas in the air bath chamber flows back to the reflux chamber through the internal circulation air exchange port to participate in the next cycle. During this process, the second temperature sensor real-time monitors the temperature change of the air bath chamber and feeds the information back to the control system. The control system adjusts the working state of the refrigeration or heating module and the rotation speed of the internal circulation fan according to the temperature deviation, so as to achieve precise control of the temperature.

[0030] Advantages of the present invention: 1. Precisely monitor the temperature inside the device and achieve feedback control of the temperature control module By setting multiple temperature sensors in the air bath chamber and the static pressure chamber, it is possible to comprehensively and accurately monitor the real-time temperature changes of the incoming and outgoing gases in the air bath chamber. By judging the abnormal temperature values in the temperature monitoring area, removing them, and then taking the average, the accurate real-time temperature of this area can be obtained. Then, by taking the weighted average of the accurate real-time temperatures of each area, the real-time temperature in the air bath chamber can be obtained. Through this multi-sensor monitoring method of dividing into multiple areas, the influence of error values can be excluded, ensuring the accuracy and integrity of temperature data. It can capture the subtle changes in the local temperature in the air bath chamber, reduce the error of single-point temperature measurement, improve the reliability and accuracy of temperature monitoring during operation, and provide a more accurate basis for temperature control. The temperature sensors timely feedback the monitored temperature information to the control system, and the control system quickly adjusts parameters such as the working power of the refrigeration or heating module according to the temperature deviation. This real-time feedback adjustment mechanism can quickly respond to temperature changes, take timely measures for adjustment, enable the temperature of the air bath chamber to quickly approach and stabilize at the target temperature, and improve the accuracy and response speed of temperature control.

[0031] 2. Optimize the air flow circulation process to enhance the uniform stability of temperature control The existence of the static pressure chamber provides a uniform and stable environment for regulating the gas. By designing the shape, size, and spacing of the air outlets of the equal-air-volume air supply duct, the turbulent flow phenomenon of the air flow at the air outlets can be reduced, ensuring that the air flow passes through the air outlets evenly and stably. By segmenting the deflector plate, the air flow velocity can be effectively reduced, and the deflection angle of each segment of the deflector plate can be independently adjusted, which can guide the air flow direction in multiple dimensions, increase the intersection and mixing of the air flow in different areas, and make the air flow more uniform. By setting the diffuser plate, the air flow is evenly dispersed to form a stable wind pressure. This reduces the influence of local temperature differences and pressure fluctuations on temperature control, ensuring that the gas entering the air bath chamber has good uniformity and stability. The closed gas circulation system enables the gas to fully circulate in the system, continuously exchange heat with the refrigeration or heating module, realizes precise temperature adjustment, and the internal circulation fan promotes the circulation of the gas, ensuring the effectiveness and stability of temperature control.

[0032] 3. Reasonable control strategy to achieve efficient and energy-saving temperature control According to the difference between the real-time temperature inside and outside the device and the target temperature, as well as different temperature conditions, the system adopts a variety of temperature control strategies. In different situations, different heating or cooling methods are selected, and the power of the refrigeration or heating module is adjusted. This flexible and diverse control strategy can adapt to various temperature control requirements and improve the accuracy of temperature control. For the operating power of the thermoelectric cooler in the refrigeration module and the heating wire in the heating module, a fuzzy PID control algorithm is adopted, which can achieve precise adjustment of the refrigeration and heating effects and ensure stable control of the temperature in the air bath chamber. Each chamber is provided with a highly efficient heat-insulating thermal insulation layer, which can effectively isolate the temperature and reduce heat loss. This enables the device to better maintain temperature stability during the temperature control process and reduce the unnecessary influence of the external environmental temperature on the internal temperature of the device. Brief Description of the Drawings

[0033] Figure 1 Structural diagram of an air bath temperature control device of the present invention.

[0034] Figure 2 Structural diagram of the static pressure chamber of an air bath temperature control device according to an embodiment of the present invention.

[0035] Figure 3 Fuzzy control diagram of an air bath temperature control method of the present invention.

[0036] Figure 4 Control logic diagram of an air bath temperature control method of the present invention.

[0037] Figure 5 Membership function curve of the fuzzy control input variable according to an embodiment of the present invention.

[0038] Figure 6 Comparison diagram of the temperature curves between the temperature control of the present invention and the traditional PID temperature control according to an embodiment of the present invention.

[0039] 1 Return chamber, 2 Static pressure chamber, 3 Air bath chamber, 4 Inner circulation air inlet, 5 Inner circulation air exchange port, 11 Inner circulation fan, 12 Refrigeration module, 121 Thermoelectric cooler, 122 Radiator, 123 Cooling fan, 124 Heat-conducting copper plate, 13 Heating module, 131 Heating wire, 14 Outer circulation air exchange port, 15 Outer circulation air exchange valve, 21 First temperature sensor, 22 Equal air volume air supply duct, 23 Deflector, 24 Diffuser plate, 31 Suspension support plate, 32 Second temperature sensor. Detailed Embodiments

[0040] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0041] It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation.

[0042] As Figure 1 shown, the air bath temperature control device of the present invention includes a reflux chamber 1, a static pressure chamber 2, an air bath chamber 3, an internal circulation air inlet 4, and an internal circulation air exchange port 5. The reflux chamber 1 includes an internal circulation fan 11, a refrigeration module 12, a heating module 13, an external circulation air exchange port 14, and an external circulation air exchange valve 15. The refrigeration module 12 further includes a refrigeration chip 121, a radiator 122, a cooling fan 123, and a heat conduction copper plate 124. The heating module 13 includes a heating wire or other heating element 131. The static pressure chamber 2 includes a plurality of first temperature sensors 21, an equal air volume air supply duct 22, a guide plate 23, and a diffuser plate 24. The air bath chamber 3 includes a suspension support plate 31 and a plurality of second temperature sensors 32. Embodiment

[0043] The device of the present invention is used for the environmental temperature control of a certain experimental process, which simulates the anaerobic fermentation process of feed in the rumen to evaluate the digestion of feed nutrients.

[0044] The reflux chamber 1 includes an internal circulation fan 11, a refrigeration module 12, a heating module 13, an external circulation air exchange port 14, and an external circulation air exchange valve 15. The internal circulation fan 11 serves as the power component for gas transportation. Its rotation speed is adjustable and can be intelligently adjusted according to different air volume requirements of the static pressure chamber 2 to ensure the stable flow of gas in the system and provide sufficient power support for temperature control. The refrigeration module 12 is used to cool and regulate the gas. The refrigeration sheet 121 is arranged on the side wall of the reflux chamber 1 and is the main refrigeration element. Based on the thermoelectric effect, it achieves the refrigeration effect by absorbing heat. Its non-working surface is exposed outside the reflux chamber, which is conducive to heat dissipation. The heat-conducting copper plate 124 is closely attached to the working surface of the refrigeration sheet 121. It has a certain thickness and gaps, which can increase the contact area with air, thereby enhancing the heat transfer performance and heat exchange efficiency, and enabling the refrigeration effect of the refrigeration sheet 121 to be better transferred to the regulated gas to achieve a better refrigeration effect. The radiator 122 is used to absorb the heat on the non-working surface of the refrigeration sheet 121, and the cooling fan 123 speeds up the heat exchange and transfer speed to ensure that the refrigeration sheet 121 can work continuously and stably, maintaining the low-temperature state of the regulated gas. The heating module 13 includes an electric heating wire or other heating elements 131 for heating the regulated gas. The electric heating wire or other heating elements 131 are arranged on the side wall of the reflux chamber 1 and heat the regulated gas by dissipating heat, providing another adjustment method for temperature control and meeting different temperature control requirements. The external circulation air exchange port 14 is used to achieve the air exchange and heat transfer between the device of the present invention and the external environment. The external circulation air exchange valve 15 is arranged on the external circulation air exchange port 14 to control the degree of air exchange and heat transfer and adjust the influence of the outside on the internal temperature of the device according to the actual temperature situation.

[0045] The static pressure chamber 2 includes a first temperature sensor 21, an equal-airflow supply air duct 22, a deflector 23, and a diffuser plate 24. As a buffer chamber, it converts dynamic pressure into static pressure, making the temperature of the regulated gas more uniform and the pressure more stable, thus providing a uniform and stable air bath environment for the air bath chamber 3. There are multiple first temperature sensors 21, evenly arranged near the diffuser plate 24, to monitor the temperature of the regulated gas near the diffuser plate 24 in real time. The real-time temperature of the gas entering the air bath chamber 3 is obtained through a multi-temperature sensor data fusion strategy, and the real-time temperature inside the air bath chamber 3 is obtained by weighted calculation with the real-time temperature of the air flowing out of the air bath chamber 3, making the temperature control more accurate and providing a reliable basis for temperature control. The air inlet of the equal-airflow supply air duct 22 is connected to the internal circulation air inlet 4, and is provided with multiple air outlets, so that the regulated gas enters the static pressure chamber 2 stably and evenly. The deflector 23 is arranged above the equal-airflow supply air duct 22, effectively covering the air outlet of the equal-airflow supply air duct 22. The deflector 23 is divided into multiple sections, which is a louver structure, effectively reducing the air flow speed and guiding the air flow direction. Each section can independently adjust the deflection angle to achieve multi-dimensional adjustment of the air flow direction, increasing the intersection and mixing of the air flow in different regions and promoting the temperature uniformity. The diffuser plate 24 is arranged above the deflector 23, as the connection between the static pressure chamber 2 and the air bath chamber 3, which is a porous structure with a certain thickness, can subdivide the air flow and adjust the air flow direction, so that the gas flows into the air bath chamber 3 stably.

[0046] The air bath chamber 3 includes a hanging support plate 31 and a second temperature sensor 32. The hanging support plate 31 is provided with holes with adjustable sizes for stably placing the reactor, so that the main part of the reactor is immersed in the stable temperature environment of the air bath chamber 3, and at the same time is in close contact with the reactor to form a sealed space inside the air bath chamber 3, reducing the influence of the external environment on the temperature inside the air bath chamber 3. There are multiple second temperature sensors 32, arranged near the internal circulation air exchange port 5, to monitor the temperature near the circulation air exchange port 5 in real time. The real-time temperature of the air flowing out of the air bath chamber 3 is obtained through a multi-temperature sensor data fusion strategy, and the real-time temperature inside the air bath chamber is obtained by weighted calculation with the real-time temperature of the air flowing into the air bath chamber 3, making the temperature monitoring more accurate and providing a reliable basis for temperature control.

[0047] The internal circulation air inlet 4 is arranged on the connection surface between the reflux chamber 1 and the static pressure chamber 3. Through the variable-diameter connection with the internal circulation fan 11, the air flow direction is adjusted to make the gas flow into the equal-airflow supply air duct 22 stably, reducing gas turbulence. The internal circulation air exchange port 5 is arranged on the connection surface between the air bath chamber 3 and the reflux chamber 1, on the side wall of the air bath chamber 3, realizing the stable circulation of gas from the air bath chamber 3 to the reflux chamber 1, the internal circulation of gas in the device, and heat exchange.

[0048] When the device of the present invention is operating, the internal air flow circulation process is as follows. The regulated gas is affected by the refrigeration and heating modules in the return cavity, and the temperature is adjusted by the refrigeration module or the heating module. Under the action of the internal circulation fan, the regulated gas flows in the device, enters the static pressure cavity through the internal circulation air inlet, converts the dynamic pressure into static pressure in the static pressure cavity, and the regulated gas uniformly and stably passes through the equal-air-volume air supply duct. Under the action of the flow guide plate, the flow velocity decreases, and the gas is fully mixed in the static pressure cavity to achieve uniform and stable temperature. Then, it stably flows into the air bath cavity through the diffuser plate, forms a stable temperature field in the air bath cavity, and the gas flows back to the return cavity through the internal circulation air exchange port, forming a closed circulation system.

[0049] There are a total of 3 first temperature sensors 21 in the static pressure cavity 2, which are evenly arranged near the diffuser plate 24 to monitor the temperature of the gas flowing into the air bath cavity 3. There are a total of 3 second temperature sensors 32 in the air bath cavity 3, which are evenly arranged near the internal circulation air exchange port 5 to monitor the temperature of the gas flowing out of the air bath cavity 3. Through the setting of these two groups of temperature sensors and the temperature data fusion strategy of the multi-temperature sensor monitoring values in this application, the real-time temperature in the air bath cavity 3 can be obtained more comprehensively and accurately, the subtle changes in the local temperature in the air bath cavity 3 can be captured, the temperature monitoring deviation caused by the position limitation of a single sensor can be avoided, the measurement error can be effectively reduced, the reliability and accuracy of temperature monitoring during operation are improved, and at the same time, a more real and detailed temperature field model can be constructed.

[0050] As Figure 2 shown, by setting the equal-air-volume air supply duct 22, the flow guide plate 23 and the diffuser plate 24 in the static pressure cavity 2, the effect of stably regulating the air flow is achieved.

[0051] The air inlet of the equal-air-volume air supply duct 22 is connected to the internal circulation air inlet 4, and there are three air outlets facing the air bath cavity 3. The shape of the air outlets is set as a rectangle to reduce the turbulent flow phenomenon at the air outlets, reduce noise and improve the ventilation efficiency; the opening size of the air outlets gradually increases along the axial direction starting from the air inlet. The air outlet opening area S(x) at a distance of x along the axial direction from the air inlet satisfies the linear relationship S(x)=0.008x + 0.01. As the distance from the air inlet increases, the air outlet area gradually increases. Through this design of gradually changing the area, the pressure loss and flow velocity change during the flow of the air flow in the pipeline are compensated; the distance between the air outlets gradually decreases along the axial direction starting from the air inlet to ensure that the air flows blown out from adjacent air outlets can be connected to each other and cover evenly, avoiding the occurrence of ventilation blind spots. Through the setting of the equal-air-volume air supply duct 22, it can be ensured that the air output of each air outlet per unit time is equal.

[0052] The flow guide plate 23 is arranged in the static pressure chamber 2, which can effectively cover the airflow range at the air outlet of the equal air volume supply air duct 22, so as to reduce the turbulence and noise generated when the airflow passes through the edge; the flow guide plate 23 is divided into multiple segments and is in the form of a louver plate structure, which can effectively reduce the airflow speed and guide the airflow direction; each segment of the flow guide plate can independently adjust its deflection angle, and adaptively adjust the deflection angle according to the deviation between the temperature values monitored by each temperature sensor, so as to realize multi-dimensional adjustment of the airflow direction, increase the intersection and mixing of the airflow in different regions, and promote the temperature uniformity.

[0053] The diffuser plate 24 is a porous plate with a certain thickness, which is provided with circular holes, and the holes and the gaps between the holes are relatively small, so that the airflow is fully subdivided and evenly dispersed when passing through the holes. The porous plate has a certain thickness, which can fix the airflow direction and enable the airflow to form a uniform wind pressure after passing through the diffuser plate.

[0054] The method for providing a temperature environment for in vitro simulation of rumen fermentation in ruminants by the device of the present invention includes: (1) Complete the installation of each component and check whether the working state is normal; (2) Set the target temperature T of the air bath chamber 3 目标 to be 39 °C; (3) Temperature sensors are arranged at the main monitoring points in the static pressure chamber 2 and the air bath chamber 3. By cross-verifying the temperature data monitored by different temperature sensors in the same area, and then calculating the average value of the reliable temperature data as the temperature data of this area, and then calculating the real-time temperature through the temperature and its weight of different areas as the monitoring temperature in the air bath chamber 3. The multi-temperature sensor data fusion strategy is as follows. ① Calculate the deviation between three temperature sensors near the diffuser plate 24 in the static pressure chamber 2 and near the internal circulation ventilation opening 5 in the air bath chamber 3:

[0055]

[0056] In the formula, D 散流板 is the deviation value between the first temperature sensors 21 near the diffuser plate 24, and T 散流板1 , T 散流板2 and T 散流板3 are the monitoring temperature values of the 1st, 2nd, and 3rd first temperature sensors near the diffuser plate 24 respectively. D 内循环换气口 is the deviation value between the second temperature sensors 32 near the internal circulation ventilation opening 5, and T 内循环换气口1 , T 内循环换气口2 and T 内循环换气口3 are the monitoring temperature values of the 1st, 2nd, and 3rd second temperature sensors near the internal circulation ventilation opening 5 respectively. D 散流板12 , D散流板23 , D 散流板13 are respectively the temperature deviation values between the second temperature sensors 1 and 2, the second temperature sensors 2 and 3, and the second temperature sensors 1 and 3 near the diffuser plate, D 内循环换气口12 , D 内循环换气口23 , D 内循环换气口13 Similarly

[0057] ② Define the allowable range of the deviation between temperature sensors in the same area:

[0058] In the formula, Dev(m, n) is the temperature value deviation between two sensors, T m and T n are respectively the monitored temperature values of the m-th and n-th temperature sensors.

[0059] If D 散流板 ≤ Dev(m, n), then D 散流板 is within the allowable range; if D 散流板 > Dev(m, n), then D 散流板 is outside the allowable range; if D 散流板 is missing, it is processed as being outside the allowable range.

[0060] If D 内循环换气口 ≤ Dev(m, n), then D 内循环换气口 is within the allowable range; if D 内循环换气口 > Dev(m, n), then D 内循环换气口 is outside the allowable range; if D 内循环换气口 is missing, it is processed as being outside the allowable range.

[0061] ③ Calculate the temperature value of this area: If D 散流板 are all within the allowable range, then take the average value of the 3 temperature sensors 21 near the diffuser plate 24 as the result; If D 散流板 are not all within the allowable range, then judge the sensors with deviations outside the range in turn. If 2 of the deviation sets involved in this sensor are outside the range, then exclude it from this temperature calculation and take the average value of the remaining temperature sensors as the result; D 内循环换气口 Similarly

[0062] ④ Calculate the temperature value of the air bath chamber 3 through the temperature values of different areas: Determine the temperature weights of the monitored areas (near the diffuser plate 24 and near the internal circulation air vent 5) based on the natural attenuation change gradient of the air flow temperature along the flow direction within the device (the possible temperature attenuation brought by normal operation when there is nothing in the cavity). The weight of the temperature near the diffuser plate 24 accounts for 0.6, and the weight of the temperature near the internal circulation air vent accounts for 0.4. Then, perform calculations based on the temperature and its weight in the monitored area to obtain the real-time temperature inside the air bath chamber 3.

[0063] In the formula, T 气浴腔 is the real-time temperature of the air bath chamber 3, and W 散流板 is the weight of the temperature near the diffuser plate 24 (0.6), and T 散流板 is the temperature value of the temperature near the diffuser plate 24, and W 内循环换气口 is the weight of the temperature near the internal circulation air vent 5 (0.4), and T 内循环换气口 is the temperature value of the temperature near the internal circulation air vent 5.

[0064] (4) As Figure 4 shown, based on the relationship between the real-time temperature T 静压 of the static pressure chamber 2 obtained, the external temperature T 环境 , the real-time temperature T 气浴 of the air bath chamber 3, and the target temperature T 目标 , as well as the difference e(k) between T 目标 and T 气浴 , jointly select an appropriate temperature control strategy.

[0065] As Figure 3 shown, according to the preset temperature error E max entering the fuzzy pid control algorithm and the preset temperature error E min entering the pid strategy library; ① When e(k) < -1°C and T 环境 < T 静压 , or e(k) > 1°C and T 环境 > T 静压 , simultaneously open the external circulation air valve 15 and the internal circulation fan 11 connecting the reflux chamber 1 to the outside. The internal circulation fan 11 operates at full power to exchange the air inside the cavity with the outside air until |e(k)| < 1°C or |T 环境 - T 静压 | < 1°C, and immediately close the external circulation air valve 11; ② When e(k) < -1°C and T 环境 > T 静压 , both the thermoelectric cooler 121 and the internal circulation fan 11 operate at full power to quickly cool the temperature of the gas inside the cavity; ③ When e(k) > 1°C and T 环境<T 静压 When 静压 , both the heating wire 131 and the internal circulation fan 11 operate at full power to rapidly increase the temperature of the gas inside the cavity; ④ When -0.4°C > e(k) > -1°C, the operating power P of the thermoelectric cooler 121 制冷片 is controlled by the fuzzy PID algorithm. The internal circulation fan 11 blows cold air into the static pressure box 2 to achieve uniform gas temperature and reduced flow velocity, and then slowly spreads it into the air bath cavity 3 through the diffuser plate 24 to reduce the cavity temperature. At the same time, the gas flows back to the reflux cavity 1 through the internal circulation air vent 5 to achieve the internal circulation of the gas in the air bath temperature control device; ⑤ When 1°C > e(k) > 0.4°C, the operating power P of the heating wire 131 电热丝 is controlled by the fuzzy PID algorithm. The internal circulation fan 11 blows hot air into the static pressure box 2 to achieve uniform gas temperature and reduced flow velocity, and then slowly spreads it into the air bath cavity 3 through the diffuser plate 24 to increase the cavity temperature. At the same time, the gas flows back to the reflux cavity 1 through the internal circulation air vent 5 to achieve the internal circulation of the gas in the air bath temperature control device; ⑥ When 0 > e(k) > -0.4°C, the power P of the thermoelectric cooler 121 制冷片 is precisely controlled by the fuzzy PID strategy library. At this time, P 制冷片 is maintained at a low level to maintain the stability of the temperature inside the cavity and avoid temperature overshoot; ⑦ When 0.4°C > e(k) > 0, the power P of the heating wire 131 电热丝 is precisely controlled by the fuzzy PID strategy library. At this time, P 电热丝 is maintained at a low level to maintain the stability of the temperature inside the cavity and avoid temperature overshoot; Set the input temperature error value E and the temperature error rate ΔE. The fuzzy subsets of the linguistic values are {Negative Big, Negative Medium, Negative Small, Zero, Positive Small, Positive Medium, Positive Big}, and are briefly recorded as {NB, NM, NS, ZO, PS, PM, PB}. Quantify the error E and the error change rate ΔE into the range of (-3, 3). The membership function curves of the input variables are as Figure 3 shown.

[0066] According to the influence of the parameters K p , K i , K d on the output characteristics of the system, summarize the control rule table of K p , K i , K d based on experimental experience, as shown in Table 1-3, Table 1 Fuzzy rule table of K p

[0067] Table 2 K i 's fuzzy rule table

[0068] Table 3 K d 's fuzzy rule table

[0069] According to the rule table and combined with the control law of the air bath incubator, for the pid parameter K p The following 49 fuzzy control rules are summarized: If E = NB and ΔE = NB, then K p = PB, If E = NB and ΔE = NM, then K p = PB, ......, If E = PB and ΔE = PB, then K p = PB, E and Ec are fuzzy input variables, and K p is the fuzzy output variable. NB, PB, NM, etc. are fuzzy sets on the universe of discourse.

[0070] To improve the safety of the heating system, generally, the method of heating with a small power for a long time is adopted. As Figure 6 shown, when the ambient temperature is 36°C and the ambient humidity is 60%RH, this device controls its temperature by using the conventional pid and fuzzy pid methods respectively. In one cycle, the corresponding speed of using the fuzzy pid control is about 25s shorter than that of the traditional pid, and the control is stable at 39°C. The traditional pid control shows overshoot and fluctuates up and down for a period of time before stabilizing. The comparison result with the traditional pid control shows that the device and method of the present invention can reach the target temperature faster and more accurately and can maintain stability for a long time.

[0071] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0072] The above-described embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent should be subject to the appended claims.

Claims

1. A gas bath temperature control device, characterized in that: include: A reflux chamber, a static pressure chamber and an air bath chamber are arranged in sequence from bottom to top; The reflux chamber includes an internal circulation fan, a cooling module, a heating module, an external circulation ventilation port, and an external circulation ventilation valve; The static pressure chamber includes a first temperature sensor, an equal air volume air supply duct, a guide plate and a diffuser; there are one or more first temperature sensors; The air bath chamber includes a hanging support plate and a second temperature sensor; the second temperature sensor has one or more; The reflux chamber is connected to the static pressure chamber via an internal circulation air inlet, the static pressure chamber is connected to the air bath chamber via the diffuser plate, and the air bath chamber is connected to the reflux chamber via an internal circulation air exchange port, forming a gas circulation passage; The internal circulation fan serves as a power component for gas transportation, and its speed is adjustable, and can be intelligently adjusted according to different air volume requirements of the static pressure chamber.

2. The device according to claim 1, characterized in that The three cavities of the reflux chamber, static pressure chamber and air bath chamber are all provided with insulation layers. The insulation layers are made of high-efficiency heat-insulating materials, which can effectively reduce the impact of the external ambient temperature on the device, ensure that temperature fluctuations are minimized and improve energy efficiency.

3. The device according to claim 1, characterized in that The refrigeration module includes a heat-conducting copper plate, a refrigeration sheet, a radiator and a cooling fan, which are used to cool the regulated gas; the refrigeration sheet is arranged on the side wall of the reflux cavity, and its non-working surface is exposed outside the reflux cavity.

4. The device according to claim 1, characterized in that The plurality of second temperature sensors in the gas bath chamber monitor the temperature of the gas bath chamber in real time, and the real-time temperature in the gas bath chamber is obtained through a multi-temperature sensor data fusion strategy.

5. The device according to claim 1, characterized in that There are multiple first temperature sensors in the static pressure chamber, which are evenly arranged near the diffuser plate to monitor the temperature of the regulated gas near the diffuser plate in real time, and obtain the real-time temperature in the gas bath chamber through a multi-temperature sensor data fusion strategy.

6. The device according to claim 1, characterized in that The air inlet of the equal air volume air supply duct is connected to the internal circulation air inlet, and is provided with a plurality of air outlets facing the air bath cavity. The shape of the air outlet is at least one of a rectangle, a trapezoid, a circle, a triangle, a fan, and an ellipse, or a regular shape composed of a plurality of small air outlets of the above shapes; the guide plate is divided into multiple sections, and the deflection angle is adaptively adjusted according to the deviation between the temperature values ​​monitored by the temperature sensor.

7. A control method applied to the device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Complete the installation of each component and check whether the working status is normal; Step 2: Set the target temperature T of the gas bath chamber 目标 ; Step 3, different areas are divided in the static pressure chamber and the gas bath chamber, and one or more first temperature sensors and second temperature sensors are respectively set in each of the divided areas, and the temperature data monitored by different temperature sensors in the same area are cross-validated, and then the average value is calculated using the reliable temperature data as the temperature data of the area, and then the real-time temperature is calculated by the temperature of different areas and their weights as the monitoring temperature in the gas bath chamber; Step 4: According to the obtained real-time temperature T of the static pressure chamber 静压 , outside temperature T 环境 , the real-time temperature of the gas bath chamber T 气浴 With the target temperature T 目标 The relationship between T 目标 With T 气浴 The difference e(k) is used to jointly select the appropriate temperature control strategy.

8. The control method according to claim 7, characterized in that: The multi-temperature sensor data fusion strategy is adopted. The specific strategy is: ① Calculate the deviation between multiple temperature sensors in the same area: ， Where D mn is the deviation value between different temperature sensors, T m and T n are the monitored temperature values ​​of the mth and nth temperature sensors respectively; ② Define the allowable range of deviation between temperature sensors in the same area: ， Where Dev(m, n) is the temperature deviation between the two sensors, T m and T n are the monitored temperature values ​​of the mth and nth temperature sensors respectively; If D mn ≤Dev(m, n), then D mn within the permitted range; If D mn > Dev(m, n), then D mn outside the permitted range; If D mn If missing, it will be treated as outside the permitted range; ③Calculate the temperature value of this area: If D mn If all are within the allowable range, the average value of all temperature sensors in the area is taken as the result; If D mn If not all of them are within the allowable range, the sensors with deviations outside the range are judged one by one. If a of the deviations involved in the sensor are outside the range, where a is a constant and is greater than half of the number of sensors, it will be removed from this temperature calculation, and the average value of the remaining temperature sensors will be taken as the result, effectively eliminating the interference of abnormal temperature points and improving the accuracy of the data; ④ Calculate the temperature of the gas bath chamber by the temperature values ​​of different areas: The temperature weight of the monitored area is determined by the change gradient of the natural temperature attenuation along the flow direction of the airflow in the device, and then the temperature and weight of the monitored area in the air bath chamber are calculated to obtain the real-time temperature in the air bath chamber. ， Where, T 气浴腔 is the real-time temperature of the gas bath chamber, N is the number of temperature monitoring areas, W m is the weight of the mth temperature monitoring area, T m is the temperature value of the mth temperature monitoring area.

9. The control method according to claim 7, characterized in that: The temperature control strategy is: According to the preset temperature error E entering the fuzzy PID control algorithm max And the preset temperature error E entering the pid strategy library min ; ①When e(k) < -E max and T 环境 < T 静压 , or e(k) > E max and T 环境 > T 静压 At this time, the external circulation ventilation valve and the internal circulation fan connecting the reflux chamber to the outside are opened simultaneously. The internal circulation fan operates at full power to exchange the air inside the chamber with the outside air until |e(k)| < E max or |T 环境 - T 静压 | < t °C, where t is a constant, and immediately close the external circulation ventilation valve; ②When e(k)<-E max And T 环境 >T 静压 When the temperature of the gas in the cavity is cooled, the refrigeration plate and the internal circulation fan are both running at full power to quickly cool down the temperature of the gas in the cavity; ③When e(k)>E max And T 环境 <T 静压 When the heating wire and the internal circulation fan are running at full power, the temperature of the gas in the cavity can be quickly increased; ④When-E min >e(k)>-E max When the operating power of the cooling plate is P 制冷片 Controlled by the fuzzy PID algorithm, the internal circulation fan blows the cold air into the static pressure box to achieve uniform gas temperature and reduced flow rate, and then spreads it into the gas bath cavity through the diffuser plate to achieve the effect of reducing the cavity temperature. At the same time, the gas flows back to the reflux cavity through the internal circulation ventilation port to achieve the internal circulation of the gas in the gas bath temperature control device; ⑤When E max >e(k)>E min When the operating power of the heating wire is P 电热丝 Controlled by the fuzzy PID algorithm, the internal circulation fan blows the hot air into the static pressure box to achieve uniform gas temperature and reduced flow rate, and then spreads it into the gas bath cavity through the diffuser plate to increase the cavity temperature. At the same time, the gas flows back to the reflux cavity through the internal circulation ventilation port to achieve the internal circulation of the gas in the gas bath temperature control device; ⑥When 0>e(k)>-E min When the cooling plate power P 制冷片 The fuzzy pid strategy library performs fine control. 制冷片 Maintain at a low level to keep the temperature in the chamber stable and avoid temperature overshoot; ⑦When E min When >e(k)>0, the power of the heating wire P 电热丝 The fuzzy pid strategy library performs fine control. 电热丝 Maintain it at a low level to keep the temperature in the chamber stable and avoid temperature overshoot.

10. The control method according to claim 7, characterized in that: Using fuzzy adaptive PID algorithm, the differential control component improves the dynamic characteristics of the system, and the integral control component reduces the static error of the system. The model is as follows: ， In the formula, K p , K i , K d The proportional coefficient, integral coefficient and differential coefficient of fuzzy PID are optimized in real time by fuzzy logic and according to fuzzy rules. e(k) is the real-time error value, and e(k-1) is the error value of the previous time. Quantized input: The fuzzy algorithm needs to quantize the input, taking the error value and error change rate as input, and projecting them to the digital level through the quantization function, which will affect the accuracy of the calculation; Calculate the membership degree: establish the fuzzy subsets of the input quantity, and calculate the corresponding membership degree according to the results of quantifying the error value and the error change rate; Build K p , K i , K d Respective fuzzy rule base: K p The selection of K value depends on the response speed of the system. In the initial stage of regulation, the temperature of the regulating gas in the system needs to rise rapidly, so a larger K value should be selected. p value to increase the response speed, and in the mid-adjustment period, K p A smaller value is taken to make the system have a smaller temperature overshoot probability and ensure a certain response speed. In the later stage of the adjustment process, K p Adjust the value to a larger value to reduce the temperature static difference; K i It is mainly used to eliminate the steady-state deviation of the system temperature. In the early stage of regulation, the temperature of the regulating gas in the system needs to rise quickly without overshooting. i A smaller value or even zero should be selected to prevent integral saturation. In the middle of the adjustment, K i The appropriate value should be increased to reduce the steady-state error and avoid affecting the stability. In the later stage of the adjustment process, K i A larger value should be selected to reduce the static error of the adjustment and ensure that the temperature is close to the target value; K d The main purpose is to change the dynamic characteristics of the system. In the early stage of regulation, the temperature of the regulating gas in the system needs to rise quickly without overshooting. d A larger value should be selected to suppress or even avoid overshoot. In the middle of the adjustment, K d The value should be appropriately smaller and remain fixed, and in the later stage of adjustment, K d The value should be reduced to weaken the braking effect of the controlled process, thereby compensating for the initial adjustment process due to K d The temperature adjustment time is prolonged due to the larger value; Fuzzy reasoning and fuzzification: For the temperature error value and error change rate, the "center of gravity method" is used according to K p , K i , K d The fuzzy rule base finds the output value and its corresponding membership degree; Clear quantification result: multiply the output value by its corresponding membership to obtain K p , K i , K d The solution of the output value is converted and corrected to obtain K for pid control p , K i , K d .

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