A gas bath temperature control device and method

Abstract

The present application aims at the problems existing in the prior art of temperature control, and provides a kind of air bath temperature control device and method.The device comprises a reflux cavity, a static pressure cavity and an air bath cavity, and each cavity is provided with a heat preservation layer.The reflux cavity has an internal circulation fan, a refrigeration module, a heating module, an external circulation air exchange port, an external circulation air exchange valve and related components;The air bath cavity has a second temperature sensor and an internal circulation air exchange port;The static pressure cavity is provided with a temperature sensor, an equal air volume air supply air duct, a guide vane and a diffuser plate.The three chambers are connected to each other through internal circulation air inlets, diffuser plates and internal circulation air exchange ports, forming a gas circulation path.The real-time temperature in the cavity is calculated by the monitoring values of multiple temperature sensors through data fusion strategy.The control method operates different temperature control strategies according to the difference between the real-time temperature of the air bath cavity and the external temperature and the difference between the real-time temperature of the air bath cavity and the target temperature.The present application has the effects of high uniformity and reliability of temperature control, high efficiency and energy saving, accurate temperature control, etc.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of temperature control, in particular to a gas bath temperature control device and method. BACKGROUND

[0002] In many scientific experiments, industrial production and medical fields, accurate temperature control is a key factor to ensure the accuracy of experimental results, product quality stability and normal operation of equipment. The existing temperature control method has many shortcomings, for example, the traditional water bath temperature control method is limited by the properties of water, which may cause adverse effects on some samples or equipment that react with water, and in some cases that require rapid heating or cooling and have high requirements for temperature uniformity, water bath temperature control is difficult to meet the demand. Compared with traditional heating methods, gas bath constant temperature has the advantages of better temperature uniformity, avoiding sample contamination and rapid temperature change capacity, and is more indispensable in the field of temperature control.

[0003] However, some gas bath temperature control devices have problems such as low temperature control precision, large temperature fluctuation, low heating or refrigeration efficiency, and excessive energy consumption, which cannot achieve precise and stable temperature control. Invention patent CN112327605B discloses a constant temperature device temperature control system and method, which controls the temperature by the cooperation of the refrigeration system, the primary heater and the secondary heater, and the circulation and mixing of the fan to the gas, but the device structure and temperature control logic are complex, the use of traditional pid (proportional-integral-derivative) control algorithm in secondary control high precision adjustment leads to unstable temperature control, and there is a certain degree of interference between primary control and secondary control, which affects the response speed and efficiency of temperature control. The gas flow is unstable due to the control of the throttle valve in the gas circuit, which cannot guarantee the uniformity of the temperature. Invention patent CN115562388B discloses a multi-mode composite and active gas bath ultra-precision temperature control device, which realizes high-precision and high-efficiency control of the temperature of the inside environment of the sealed box through multi-mode composite control and reasonable isolation and decoupling measures, but the structure is relatively complex between each component in order to achieve isolation and decoupling, the temperature sensor is difficult to monitor the true value, and the combination of multiple components increases the operation cost, and the control logic is complex and difficult to be practically applied to various working conditions. Chinese invention patent application CN114063671A discloses a CT data acquisition system constant temperature control device and method, which uses multiple temperature sensors to monitor the real-time temperature, and sets the weight 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, but it does not judge whether the monitoring value of the temperature sensor is accurate, and the weighted average is taken as the real-time temperature value, which cannot eliminate the influence of temperature abnormal value. SUMMARY

[0004] Therefore, it is necessary to provide a gas bath temperature control device and method to solve the above problems.

[0005] The gas bath temperature control device comprises a reflux cavity, a static pressure cavity and a gas bath cavity, all of which are provided with a heat preservation layer made of high-efficiency heat insulation material, which can effectively reduce the influence of external environment temperature on the device, minimize temperature fluctuation and improve energy use efficiency.

[0006] The reflux cavity comprises an inner circulating fan, a refrigeration module, a heating module, an outer circulating air inlet and an outer circulating air valve. The inner circulating fan serves as a power component for gas delivery, and its rotating speed can be adjusted to intelligently adjust the different air volume requirements of the static pressure cavity, ensuring stable flow of gas in the system and providing sufficient power support for temperature control. The refrigeration module comprises a heat-conducting copper plate, a refrigeration fin, a radiator and a cooling fan, which are used to cool and regulate the gas. The refrigeration fin is arranged on the side wall of the reflux cavity and is the main refrigeration element. It realizes refrigeration effect by absorbing heat based on thermoelectric effect. Its non-working surface is exposed outside the reflux cavity, which is conducive to heat dissipation. The heat-conducting copper plate is tightly attached to the working surface of the refrigeration fin and has a certain thickness and gap, which can increase the contact area with air, thereby enhancing the heat transfer performance and heat exchange efficiency, so that the refrigeration effect of the refrigeration fin is better transmitted to the regulated gas to achieve better refrigeration effect. The radiator is used to absorb heat on the non-working surface of the refrigeration fin, and the cooling fan accelerates the exchange and transmission speed of heat, ensuring that the refrigeration fin can work continuously and stably to maintain the low-temperature state of the regulated gas. The heating module comprises an electric heating wire or other heating element, which is used to heat the regulated gas. The electric heating wire or other heating element is arranged on the side wall of the reflux cavity, and heats the regulated gas by emitting heat, providing another adjustment method for temperature control and meeting different temperature control requirements. The outer circulating air inlet is used to realize air exchange and heat transfer between the device and the external environment. The outer circulating air valve is arranged on the outer circulating air inlet and is used to control the degree of air exchange and heat transfer, and adjust the influence of the external environment on the internal temperature of the device according to the actual temperature.

[0007] The gas bath cavity comprises a hanging support plate and a second temperature sensor. The hanging support plate is provided with holes of adjustable size for stably placing the reactor, so that the main body of the reactor is immersed in the stable temperature environment of the gas bath cavity, and the reactor is in close contact with the gas bath cavity to form a sealed space, thereby reducing the influence of the external environment on the temperature in the gas bath cavity. The second temperature sensor has multiple sensors arranged near the inner circulating air inlet to monitor the temperature in the gas bath cavity in real time. The real-time temperature of the outflow gas in the gas bath cavity is obtained through a multi-temperature sensor data fusion strategy, and the real-time temperature of the inflow gas in the gas bath cavity is obtained through weighted calculation, so that the temperature monitoring is more accurate and provides a reliable basis for temperature control.

[0008] The static pressure cavity includes a first temperature sensor, an equal air volume air supply air duct, a flow guide plate, and a diffuser plate, acts as a buffer cavity, converts dynamic pressure to static pressure, makes the temperature of the regulated gas more uniform and the pressure more stable, thereby providing a uniform and stable air bath environment for the air bath cavity; the first temperature sensor is multiple and uniformly arranged near the diffuser plate, monitors the temperature of the regulated gas near the diffuser plate in real time, obtains the real-time temperature entering the air bath cavity through a multi-temperature sensor data fusion strategy, and obtains the real-time temperature in the air bath cavity through weighted calculation of the real-time temperature of the air flow flowing out of the air bath cavity, so that the temperature control is more accurate and a reliable basis is provided for temperature control.

[0009] The equal air volume air supply air duct, the flow guide plate, and the diffuser plate are arranged to stabilize the regulated air flow.

[0010] The air inlet of the equal air volume air supply air duct is connected with the internal circulation air inlet, is provided with multiple 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 sector, and an ellipse, or a regular shape composed of multiple small air outlets with the above shapes, and the edges and corners can be transitioned with rounded corners to reduce turbulence of the air flow at the air outlet, reduce noise, and improve ventilation efficiency; the opening size of the air outlet gradually increases along the axial direction from the air inlet, the opening area S(x) of the air outlet at a distance x from the air inlet along the axial direction satisfies a 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.), and the opening area of the air outlet gradually increases with the increase of the distance from the air inlet, so that the pressure loss and flow rate change of the air flow in the pipeline are compensated by the gradual change of the area; the distance between the air outlets gradually decreases along the axial direction from the air inlet to ensure that the air flows blown out of adjacent air outlets can be connected to each other and uniformly covered, and blind areas are avoided. The shape, size, and distance of the air outlet of the equal air volume air supply air duct are arranged to ensure that the output air volume of each air outlet per unit time is equal.

[0011] The flow guide plate is arranged in the static pressure cavity and can effectively cover the air flow range of the air outlet of the equal air volume air supply air duct to reduce turbulence and noise generated when the air flow passes through the edge; the flow guide plate is divided into multiple sections and has a louver plate or a perforated plate structure, effectively reduces the air flow speed, and guides the flow direction of the air flow; each section of the flow guide plate can be independently adjusted in deflection angle, adaptively adjusts the deflection angle according to the deviation between the temperature values monitored by each temperature sensor, realizes multi-dimensional adjustment of the air flow direction, increases the intersection and mixing of the air flow in different areas, and promotes the uniformity of the temperature.

[0012] The flow diffuser plate is a porous plate with a certain thickness or a flow uniformizing plate with spoiler; if it is a porous plate, the hole shape can be circular, regular hexagonal, triangular or any shape or combination of multiple shapes, and the hole and the gap between the holes are relatively small, so that the airflow is fully subdivided and uniformly dispersed when passing through the hole, and the porous plate has a certain thickness, which can fix the airflow direction, so that the airflow can form uniform wind pressure after passing through the flow diffuser plate; if it is a flow uniformizing plate with spoiler, the spoiler is designed in arc shape or multi-fold line shape, so that the airflow is gently diverted and mixed; the direction of the spoiler is staggered on the surface of the flow diffuser plate according to a certain rule, and the included angle between the spoiler and the flow diffuser plate is between 30° and 45°, so that the airflow can be fully mixed and uniform wind pressure is formed.

[0013] The inner circulation air inlet is arranged on the connecting surface of the backflow cavity and the static pressure cavity, and adjusts the airflow direction through the variable-diameter connection with the inner circulation fan, so that the gas flows into the air supply duct with uniform air volume and reduces the gas turbulence; the inner circulation air outlet is arranged on the connecting surface of the air bath cavity and the backflow cavity and is located on the side wall of the air bath cavity, so that the stable circulation of the gas from the air bath cavity to the backflow cavity, the inner circulation of the gas in the device and the heat exchange are realized.

[0014] The relationship between the temperature change range of the gas in the device and the required power is as follows,

[0015] ,

[0016] In the formula, P max is the power required for temperature change, p is the gas density, V is the gas volume, C P is the specific heat capacity of air, Delta T is the maximum difference between the target temperature and the real-time temperature, and t is the gas circulation time.

[0017] The application also provides a control method based on the air bath temperature control device, which comprises the following steps:

[0018] (1) completing the installation of each component and checking whether the working state is normal;

[0019] (2) setting the target temperature T 目标 of the air bath cavity;

[0020] (3) dividing different regions in the static pressure cavity and the air bath cavity, setting one or more first temperature sensors and second temperature sensors in each region, cross-verifying the temperature data monitored by different temperature sensors in the same region, calculating the average value of the reliable temperature data in the region as the temperature data of the region, and calculating the real-time temperature as the monitoring temperature in the air bath cavity through the temperature and weight of different regions, wherein the multi-temperature sensor data fusion strategy of the monitoring temperature in the air bath cavity is as follows,

[0021] ① The mutual calculation of the deviation between multiple temperature sensors in the same region:

[0022] ,

[0023] In the formula, D mn is the deviation value between different temperature sensors, T m and T n are the monitoring temperature values of the mth and nth temperature sensors, respectively.

[0024] ② Definition of the allowable range of the deviation between temperature sensors in the same region:

[0025] ,

[0026] In the formula, Dev(m, n) is the temperature value deviation between two sensors, T m and T n are the monitoring temperature values of the mth and nth temperature sensors, respectively.

[0027] If D mn ≤ Dev(m, n), then D mn is within the allowable range;

[0028] If D mn > Dev(m, n), then D mn is outside the allowable range;

[0029] If D mn is missing, it is treated as being outside the allowable range.

[0030] ③ Calculation of the temperature value in the region:

[0031] If all D mn are within the allowable range, the average value of all temperature sensors in the region is taken as the result;

[0032] If not all D mn are within the allowable range, the sensors whose deviations are outside the range are sequentially judged. If there are a number of deviations outside the range in the set of deviations related to the sensor, where a is a constant greater than half the number of sensors, the sensor is excluded from the current temperature calculation, and the average value of the remaining temperature sensors is taken as the result, which can effectively eliminate the interference of abnormal temperature points and improve the accuracy of the data.

[0033] ④ Calculation of the temperature value of the gas bath cavity through the temperature values of different regions:

[0034] The temperature weight of the monitored region is determined by the natural attenuation gradient of the temperature of the airflow along the flow direction in the device, and the real-time temperature in the gas bath cavity is obtained by operating the temperature of the monitored region and its weight in the gas bath cavity,

[0035]

[0036] In the formula, 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.

[0037] (4) According to the obtained static pressure chamber real-time temperature T 静压 , the ambient temperature T 环境 , the real-time temperature T 气浴 of the gas bath chamber, and the target temperature T 目标 , and the difference e(k) between T 目标 and T 气浴 , a suitable temperature control strategy is jointly selected.

[0038] 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;

[0039] 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 , the outer circulation air valve connected to the backflow chamber and the ambient environment and the inner circulation fan are simultaneously opened, the inner circulation fan is operated at full power, the air in the chamber and the ambient air are exchanged, until |e(k)|<E max or |T 环境 -T 静压 |<t℃ (t is a constant, which can be set), the outer circulation air valve is immediately closed;

[0040] ② When e(k)<-E max and T 环境 >T 静压 , the refrigeration piece and the inner circulation fan are operated at full power to quickly cool the temperature of the gas in the chamber;

[0041] ③ When e(k)>E max and T 环境 <T 静压 , the electric heating wire and the inner circulation fan are operated at full power to quickly increase the temperature of the gas in the chamber;

[0042] ④ When -E min >e(k)>-E max , the operating power P 制冷片Controlled by fuzzy PID algorithm, the inner circulating fan blows cold air into the static pressure box to realize uniform gas temperature and flow rate reduction, and then slowly spreads to the air bath cavity through the diffuser plate to realize the function of reducing the cavity temperature, while the gas flows back to the reflux cavity through the inner circulating air port to realize the inner circulation of the gas in the air bath temperature control device.

[0043] ⑤When E max >e(k)>E min , the operating power P 电热丝 of the heating wire is controlled by the fuzzy PID algorithm, the inner circulating fan blows hot air into the static pressure box to realize uniform gas temperature and flow rate reduction, and then slowly spreads to the air bath cavity through the diffuser plate to realize the function of improving the cavity temperature, while the gas flows back to the reflux cavity through the inner circulating air port to realize the inner circulation of the gas in the air bath temperature control device.

[0044] ⑥When 0>e(k)>-E min , the power P 制冷片 of the refrigeration sheet is controlled by the fuzzy PID strategy library, P 制冷片 is maintained at a low level to maintain the stability of the temperature in the cavity and avoid temperature overshoot.

[0045] ⑦When E min >e(k)>0, the power P 电热丝 of the heating wire is controlled by the fuzzy PID strategy library, P 电热丝 is maintained at a low level to maintain the stability of the temperature in the cavity and avoid temperature overshoot.

[0046] The air temperature in the device has a delay, from the detection that the temperature in the device is less than the target value to the start of heating, the temperature in 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 in the device is always fluctuating up and down, the fuzzy adaptive PID algorithm can better solve such problems, 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,

[0047]

[0048] In the formula, K p , K i , and K d are the proportional coefficient, integral coefficient, and differential coefficient of the fuzzy PID, which are optimized in real time by fuzzy logic and according to certain fuzzy rules, e(k) is the real-time error value, and e(k-1) is the error value of the last time,

[0049] Quantization of input: the input quantity needs to be quantized, and the error value and error change rate are taken as the input quantity, which is projected to a certain digital level by the quantization function, which will affect the accuracy of the calculation.

[0050] Calculate membership: establish fuzzy subsets of input quantity, and calculate their respective membership degrees according to the quantization results of error value and error change rate.

[0051] Establish K p , K i , K d Each fuzzy rule base: K p The selection of K p value depends on the response speed of the system. In the early stage of adjustment, the temperature of the control gas in the system needs to be raised quickly without overshoot, so a larger K p value should be selected to improve the response speed. In the middle stage of adjustment, K p value should be smaller 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 i value is adjusted to a larger value to reduce the temperature static error and improve the control accuracy of the temperature; K i is mainly used to eliminate the steady-state deviation of the system temperature. In the early stage of adjustment, the temperature of the control gas in the system needs to be raised quickly without overshoot, so a smaller K i value should be selected or even zero to prevent integral saturation. In the middle stage of adjustment, K i value should be appropriately increased to select a moderate value to reduce the steady-state error and avoid affecting stability. In the later stage of the adjustment process, K d value should be selected to a larger value to reduce the static error of adjustment and ensure that the temperature is near the target value; K d is mainly to change the dynamic characteristics of the system. In the early stage of adjustment, the temperature of the control gas in the system needs to be raised quickly without overshoot, so a larger K d value should be selected to suppress or even avoid overshoot. In the middle stage of adjustment, K d value should be appropriately small and remain unchanged. In the later stage of adjustment, K d value should be reduced to weaken the braking effect of the controlled process, thereby compensating for the temperature regulation time extension caused by the larger K p value in the early stage of the adjustment process.

[0052] Fuzzy inference demists: for the error value and error change rate of temperature, the "barycenter method" can be used to find the output value and its corresponding membership degree according to the fuzzy rule base of K i , K d .

[0053] Clear quantization results: multiply the output value and its corresponding membership degree to obtain K p , K i, K d The solution of the output value is converted and corrected to obtain K for the PID control p , K i , K d .

[0054] When the device of the application is running, the internal air circulation process is as follows: the control gas in the reflux cavity is affected by the refrigeration and heating modules, the temperature is adjusted by the refrigeration module or the heating module, and the control gas flows in the device under the action of the internal circulation fan, 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 control gas uniformly and stably passes through the equal air volume air supply air duct, and the flow rate is reduced under the action of the guide plate, and is fully mixed in the static pressure cavity to achieve uniform and stable temperature, and then stably flows into the air bath cavity through the diffuser plate, and a stable temperature field is formed in the air bath cavity, and the gas flows back to the reflux cavity through the internal circulation air inlet, forming a closed circulation system.

[0055] Specific links:

[0056] Refrigeration or heating process: when the temperature of the air bath cavity needs to be reduced, the refrigeration module starts to work, the refrigeration fin works, the heat is transferred to the radiator through the heat-conducting copper plate, and the cooling fan accelerates the heat dissipation, so that the control gas is cooled. When the temperature of the air bath cavity needs to be increased, the heating wire of the heating module generates heat to heat the control gas.

[0057] Static pressure cavity effect: the control gas uniformly enters the static pressure cavity under the action of the equal air volume air supply air duct, changes the flow direction under the action of the guide plate, increases the travel, fully mixes, and makes the temperature distribution more uniform. Subsequently, the gas is uniformly distributed through the diffuser plate, the pressure fluctuation is reduced, and the gas enters the air bath cavity in a stable state.

[0058] Air bath cavity circulation: the gas in the air bath cavity flows back to the reflux cavity through the internal circulation air inlet to participate in the next cycle. In this process, the second temperature sensor monitors the temperature change of the air bath cavity in real time, and feeds back the information to the control system. The control system adjusts the working state of the refrigeration or heating module and the rotating speed of the internal circulation fan according to the temperature deviation, so as to realize accurate control of the temperature.

[0059] Advantages of the application:

[0060] 1. Accurate monitoring of the temperature in the device and feedback control of the temperature control module

[0061] By setting multiple temperature sensors in the gas bath cavity and the static pressure cavity, the real-time temperature changes of the gas entering and exiting the gas bath cavity can be comprehensively and accurately monitored. By judging the abnormal temperature values in the temperature monitoring area and excluding them, the accurate real-time temperature of the area can be obtained. Then, the real-time temperatures of each area are weighted and averaged to obtain the real-time temperature in the gas bath cavity. This multi-region multi-sensor monitoring can eliminate the influence of error values, ensure the accuracy and integrity of the temperature data, capture the subtle changes in the local temperature of the gas bath cavity, reduce the error of single-point temperature measurement, and improve the reliability and accuracy of temperature monitoring during operation. This provides a more accurate basis for temperature control. The temperature sensor feeds back the monitored temperature information to the control system in real time. The control system adjusts the working power and other parameters of the refrigeration or heating module according to the temperature deviation. This real-time feedback adjustment mechanism can quickly respond to temperature changes and take timely measures to adjust the temperature of the gas bath cavity to quickly approach and stabilize at the target temperature, improving the precision and response speed of temperature control.

[0062] 2. Optimizing air circulation process to enhance uniformity and stability of temperature control

[0063] The presence of the static pressure cavity provides a uniform and stable environment for gas regulation. By designing the shape, size, and spacing of the air outlet of the equal air volume air supply duct, the turbulence of the airflow at the air outlet can be reduced, ensuring uniform and stable airflow through the air outlet. By segmenting the guide plate, the airflow speed can be effectively reduced, and the deflection angle of each segment of the guide plate can be independently adjusted to guide the airflow in multiple dimensions, increasing the intersection and mixing of airflow in different areas, making the airflow more uniform. The setting of the diffuser plate makes the airflow evenly dispersed, forming a stable air pressure. This reduces the impact of local temperature differences and pressure fluctuations on temperature control, ensuring that the gas entering the gas bath cavity has good uniformity and stability. The closed gas circulation system allows the gas to circulate fully within the system, constantly exchanging heat with the refrigeration or heating module, achieving accurate temperature regulation. The internal circulation fan promotes the circulation of the gas, ensuring the effectiveness and stability of temperature control.

[0064] 3. Reasonable control strategy to achieve efficient and energy-saving temperature control

[0065] According to the difference between the real-time temperature inside and outside the device and the target temperature and different temperature conditions, the system adopts multiple temperature control strategies, selects different heating or cooling modes and adjusts the power of the refrigeration or heating module in different situations, and the flexible and diverse control strategy can adapt to various temperature control requirements and improve the accuracy of temperature control. The fuzzy PID control algorithm is adopted for the operation power of the refrigeration sheet in the refrigeration module and the heating wire in the heating module, so that the refrigeration and heating effects can be accurately adjusted, and the stable control of the air bath cavity temperature is ensured. The heat preservation layer with high efficiency is arranged in each cavity, which can effectively isolate the temperature and reduce the heat loss, so that the device can better maintain the temperature stability during the temperature control process and reduce the unnecessary influence of the external environment temperature on the internal temperature of the device. BRIEF DESCRIPTION OF DRAWINGS

[0066] Figure 1 The structure diagram of the air bath temperature control device.

[0067] Figure 2 The static pressure cavity structure of the air bath temperature control device.

[0068] Figure 3 The fuzzy control diagram of the air bath temperature control method.

[0069] Figure 4 The control logic diagram of the air bath temperature control method.

[0070] Figure 5 The membership function curve of the fuzzy control input variable of the embodiment.

[0071] Figure 6 The temperature curve comparison diagram of the temperature control and the traditional PID temperature control.

[0072] 1 reflux cavity, 2 static pressure cavity, 3 air bath cavity, 4 inner circulation air inlet, 5 inner circulation air outlet, 11 inner circulation fan, 12 refrigeration module, 121 refrigeration sheet, 122 radiator, 123 heat dissipation fan, 124 heat conduction copper plate, 13 heating module, 131 heating wire, 14 outer circulation air outlet, 15 outer circulation air valve, 21 first temperature sensor, 22 air supply air duct with equal air volume, 23 guide plate, 24 diffusion plate, 31 suspension support plate, 32 second temperature sensor. DETAILED DESCRIPTION

[0073] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0074] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0075] like Figure 1 As 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 cooling module 12, a heating module 13, an external circulation air exchange port 14, and an external circulation air exchange valve 15. The cooling module 12 further includes a cooling element 121, a radiator 122, a cooling fan 123, and a thermally conductive copper plate 124. The heating module 13 includes a heating wire or other heating element 131. The static pressure chamber 2 includes multiple first temperature sensors 21, an equal airflow air duct 22, a guide plate 23, and a diffuser 24. The air bath chamber 3 includes a suspension plate 31 and multiple second temperature sensors 32. Example

[0076] The device of the present invention was used for environmental temperature control in an experimental process that simulated the anaerobic fermentation process of feed in the rumen to evaluate the digestibility of the feed's nutrients.

[0077] The backflow cavity 1 comprises 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 is a power component for gas delivery, and its rotating speed can be adjusted intelligently according to the different air volume requirements of the static pressure cavity 2, so as to ensure the stable flow of gas in the system and provide sufficient power support for temperature control. The refrigeration module 12 is used for cooling the regulated gas. The refrigeration fin 121 is arranged on the side wall of the backflow cavity 1 and is the main refrigeration element. The refrigeration fin 121 achieves refrigeration effect by absorbing heat based on the thermoelectric effect. The non-working surface of the refrigeration fin 121 is exposed outside the backflow cavity, which is conducive to heat dissipation. The heat-conducting copper plate 124 is tightly attached to the working surface of the refrigeration fin 121 and has a certain thickness and gap, which can increase the contact area with air, thereby enhancing the heat transfer performance and heat exchange efficiency, so that the refrigeration effect of the refrigeration fin 121 is better transmitted 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 fin 121, and the cooling fan 123 accelerates the heat exchange and transmission speed, so that the refrigeration fin 121 can work continuously and stably, and the low-temperature state of the regulated gas is maintained. The heating module 13 comprises an electric heating wire or other heating element 131, which is used to heat the regulated gas. The electric heating wire or other heating element 131 is arranged on the side wall of the backflow cavity 1, and heats the regulated gas by emitting heat, thereby providing another adjustment method for temperature control and meeting different temperature control requirements. The external circulation air exchange port 14 is used to realize air exchange and heat transfer between the device and the external environment. The external circulation air exchange valve 15 is arranged on the external circulation air exchange port 14 and is used to control the degree of air exchange and heat transfer, so as to adjust the influence of the external environment on the internal temperature of the device according to the actual temperature.

[0078] The static pressure cavity 2 includes a first temperature sensor 21, an equal air volume air supply air duct 22, a flow guide plate 23 and a diffusion plate 24, serves as a buffer cavity, converts dynamic pressure to static pressure, makes the temperature of the regulated gas more uniform and the pressure more stable, thereby providing a uniform and stable air bath environment for the air bath cavity 3; the first temperature sensor 21 is multiple and uniformly arranged near the diffusion plate 24, monitors the temperature of the regulated gas near the diffusion plate 24 in real time, obtains the real-time temperature of the regulated gas entering the air bath cavity 3 through a multi-temperature sensor data fusion strategy, and obtains the real-time temperature in the air bath cavity 3 through weighted calculation of the real-time temperature of the air flow out of the air bath cavity 3 and the real-time temperature of the air flow into the air bath cavity 3, so that the temperature control is more accurate and a reliable basis is provided for temperature control; the air inlet of the equal air volume air supply air duct 22 is connected with the inner circulation air inlet 4 and is provided with multiple air outlets, so that the regulated gas stably and uniformly enters the static pressure cavity 2; the flow guide plate 23 is arranged above the equal air volume air supply air duct 22 and effectively covers the air outlets of the equal air volume air supply air duct 22, the flow guide plate 23 is divided into multiple sections and is in a louver structure, effectively reduces the air flow speed, guides the flow direction of the air flow, each section can independently adjust the deflection angle, realizes multi-dimensional adjustment of the air flow direction, increases the intersection and mixing of the air flow in different areas, and promotes the uniformity of the temperature; the diffusion plate 24 is arranged above the flow guide plate 23, serves as the connection between the static pressure cavity 2 and the air bath cavity 3, is a porous structure with a certain thickness, can subdivide the air flow and adjust the air flow direction, and makes the gas stably flow into the air bath cavity 3.

[0079] The air bath cavity 3 includes a suspension support plate 31 and a second temperature sensor 32; the suspension support plate 31 is provided with holes with adjustable sizes, is used for stably placing the reactor, makes the main body part of the reactor immersed in the stable temperature environment of the air bath cavity 3, and simultaneously closely contacts with the reactor to form a sealed space in the air bath cavity 3, thereby reducing the influence of the external environment on the temperature in the air bath cavity 3; the second temperature sensor 32 is multiple and arranged near the inner circulation air outlet 5, monitors the temperature near the circulation air outlet 5 in real time, obtains the real-time temperature of the air flow out of the air bath cavity 3 through a multi-temperature sensor data fusion strategy, and obtains the real-time temperature in the air bath cavity through weighted calculation of the real-time temperature of the air flow into the air bath cavity 3 and the real-time temperature of the air flow out of the air bath cavity 3, so that the temperature monitoring is more accurate and a reliable basis is provided for temperature control.

[0080] The inner circulation air inlet 4 is arranged on the connecting surface between the backflow cavity 1 and the static pressure cavity 3, adjusts the air flow direction through the variable-diameter connection with the inner circulation fan 11, makes the gas stably flow into the equal air volume air supply air duct 22, and reduces the turbulent flow of the gas; the inner circulation air outlet 5 is arranged on the connecting surface between the air bath cavity 3 and the backflow cavity 1 and is located on the side wall of the air bath cavity 3, realizes the stable flow of the gas from the air bath cavity 3 to the backflow cavity 1, the inner circulation of the gas in the device and heat exchange.

[0081] When the device of the present application is in operation, the internal air circulation process is as follows: the control gas is subjected to the action of the refrigeration and heating modules in the reflux cavity, the temperature is adjusted by the refrigeration module or the heating module, the control gas is subjected to the action of the internal circulation fan, the control gas flows in the device, enters the static pressure cavity through the internal circulation air inlet, the dynamic pressure is converted into static pressure in the static pressure cavity, the control gas uniformly and stably passes through the equal air volume air supply air duct, the flow rate is reduced by the action of the guide plate, the temperature is uniformly and stably mixed in the static pressure cavity, and then the control gas stably flows into the air bath cavity through the diffuser plate, a stable temperature field is formed in the air bath cavity, and the gas flows back to the reflux cavity through the internal circulation air outlet, forming a closed circulation system.

[0082] The first temperature sensor 21 in the static pressure cavity 2 has a total of three, which are uniformly arranged near the diffuser plate 24, and monitor the temperature of the gas flowing into the air bath cavity 3. The second temperature sensor 32 in the air bath cavity 3 has a total of three, which are uniformly arranged near the internal circulation air outlet 5, and monitor the temperature of the gas flowing out of the air bath cavity 3. Through the arrangement of the two groups of temperature sensors and the temperature data fusion strategy of the multiple temperature sensors in the present application, the real-time temperature in the air bath cavity 3 can be more comprehensively and accurately obtained, the subtle changes of 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 in the operation process are improved, and a more real and detailed temperature field model can be constructed.

[0083] As shown in Figure 2 The equal air volume air supply air duct 22, the guide plate 23 and the diffuser plate 24 are arranged in the static pressure cavity 2 to realize the stable control of the air flow.

[0084] The air inlet of the equal air volume air supply air duct 22 is connected with the internal circulation air inlet 4, and is provided with three air outlets facing the air bath cavity 3. The shape of the air outlet is rectangular to reduce the turbulence phenomenon of the air flow at the air outlet, reduce the noise and improve the ventilation efficiency; the opening size of the air outlet gradually increases along the axial direction from the air inlet, and the opening area S(x) of the air outlet at a distance x from the air inlet along the axial direction satisfies the linear relationship S(x)=0.008x+0.01. With the increase of the distance from the air inlet, the area of the air outlet gradually increases. Through the design of the gradually changing area, the pressure loss and flow rate change of the air flow in the pipeline during the flow process are compensated; the distance between the air outlets gradually decreases along the axial direction from the air inlet to ensure that the air flows blown out of adjacent air outlets can be connected and uniformly covered, and blind areas are avoided. Through the arrangement of the equal air volume air supply air duct 22, the output air volume of each air outlet per unit time can be ensured to be equal.

[0085] The guide vane 23 is installed inside the static pressure chamber 2, which can effectively cover the airflow range of the outlet of the equal airflow duct 22 to reduce turbulence and noise generated when the airflow passes through the edge. The guide vane 23 is divided into multiple sections and has a louvered structure, which effectively reduces the airflow speed and guides the airflow direction. Each section of the guide vane can independently adjust its deflection angle. According to the deviation between the temperature values ​​monitored by each temperature sensor, the deflection angle is adjusted adaptively to achieve multi-dimensional adjustment of the airflow direction, increase the convergence and mixing of airflow in different areas, and promote temperature uniformity.

[0086] The diffuser plate 24 is a perforated plate with a certain thickness and circular holes. The holes and the gaps between them are relatively small, so that the airflow is fully subdivided and evenly dispersed when passing through the holes. The perforated plate has a certain thickness, which can fix the airflow direction and make the airflow form a uniform wind pressure after passing through the diffuser plate.

[0087] The method for providing a temperature environment that simulates rumen fermentation in ruminants using the apparatus of the present invention includes:

[0088] (1) Complete the installation of each component and check whether the working status is normal;

[0089] (2) Set the target temperature T of the air bath chamber 3 目标 It is 39℃;

[0090] (3) Temperature sensors are installed at the main monitoring points in the static pressure chamber 2 and the air bath chamber 3. The temperature data monitored by different temperature sensors in the same area are cross-validated, and the average value of the reliable temperature data is calculated as the temperature data of the area. The real-time temperature is calculated as the monitoring temperature in the air bath chamber 3 by calculating the temperature of different areas and their weights. The multi-temperature sensor data fusion strategy is as follows.

[0091] ① Calculate the deviations between three temperature sensors near the diffuser plate 24 in static pressure chamber 2 and near the recirculation air inlet 5 in air bath chamber 3:

[0092]

[0093]

[0094] In the formula, D 散流板 T represents the deviation value between the first temperature sensors 21 near the diffuser 24. 散流板1 T 散流板2 and T 散流板3 These are the monitored temperature values ​​of the first, second, and third first temperature sensors near the diffuser 24, respectively. 内循环换气口 T represents the deviation value between the second temperature sensor 32 near the internal circulation air exchange port 5. 内循环换气口1 T 内循环换气口2 and T内循环换气口3 D 散流板12 , D 散流板23 , D 散流板13 , D 内循环换气口12 , D 内循环换气口23 , D 内循环换气口13 , D

[0095] ② Define the allowed range of temperature deviation between temperature sensors in the same area:

[0096]

[0097] In the formula, Dev(m, n) is the temperature value deviation between two sensors, T m and T n are the monitored temperature values of the mth and nth temperature sensors, respectively.

[0098] If D 散流板 ≤ Dev(m, n), then D 散流板 is within the allowed range; if D 散流板 > Dev(m, n), then D 散流板 is outside the allowed range; if D 散流板 is missing, it is treated as outside the allowed range.

[0099] If D 内循环换气口 ≤ Dev(m, n), then D 内循环换气口 is within the allowed range; if D 内循环换气口 > Dev(m, n), then D 内循环换气口 is outside the allowed range; if D 内循环换气口 is missing, it is treated as outside the allowed range.

[0100] ③ Calculate the temperature value of the area:

[0101] If D 散流板 are all within the allowed range, take the average of the three temperature sensors 21 near the diffuser plate 24 as the result;

[0102] If D 散流板 are not all within the allowed range, then the sensors with deviations outside the range are sequentially judged, if there are two sensors with deviations outside the range in the involved deviation set, then they are excluded from this temperature calculation, and the average value of the remaining temperature sensors is taken as the result; D 内循环换气口 Similarly.

[0103] ④ Calculate the temperature value of the gas bath cavity 3 through the temperature values of different areas:

[0104] The temperature weight of the monitored area (near the diffuser plate 24, near the inner circulating air inlet 5) is determined by the natural attenuation gradient of the temperature of the airflow in the device along the flow direction (the possible temperature attenuation caused by normal operation when there is nothing in the cavity), the temperature weight near the diffuser plate 24 is 0.6, and the temperature weight near the inner circulating air inlet is 0.4. The real-time temperature in the air bath cavity 3 is obtained by calculating the temperature of the monitored area and its weight,

[0105]

[0106] In the formula, T 气浴腔 is the real-time temperature of the air bath cavity 3, W 散流板 is the temperature weight near the diffuser plate 24 (0.6), T 散流板 is the temperature value near the diffuser plate 24, W 内循环换气口 is the temperature weight near the inner circulating air inlet 5 (0.4), and T 内循环换气口 is the temperature value near the inner circulating air inlet 5.

[0107] (4) As shown in Figure 4 , according to the obtained real-time temperature T 静压 of the static pressure cavity 2, the ambient temperature T 环境 , the real-time temperature T 气浴 of the air bath cavity 3, and the target temperature T 目标 , and the difference e(k) between T 目标 and T 气浴 , the appropriate temperature control strategy is selected.

[0108] As shown in Figure 3 , 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;

[0109] ① When e(k)<-1℃ and T 环境 <T 静压 , or e(k)>1℃ and T 环境 >T 静压 , the outer circulating air valve 15 connected to the backflow cavity 1 and the outside and the inner circulating fan 11 are simultaneously opened, the inner circulating fan 11 is operated at full power, the air in the cavity is exchanged with the outside air until |e(k)|<1℃ or |T 环境 -T 静压 |<1℃, and the outer circulating air valve 11 is immediately closed;

[0110] ② When e(k)<-1℃ and T 环境 >T 静压When e(k) > 1℃, both the refrigeration sheet 121 and the inner circulating fan 11 are in full power operation to rapidly cool the temperature of the gas in the cavity;

[0111] When e(k) > 1℃, both the refrigeration sheet 121 and the inner circulating fan 11 are in full power operation to rapidly cool the temperature of the gas in the cavity; 环境 <T 静压 When e(k) > 1℃, both the refrigeration sheet 121 and the inner circulating fan 11 are in full power operation to rapidly cool the temperature of the gas in the cavity;

[0112] When -0.4℃ > e(k) > -1℃, the operation power P 制冷片 The inner circulating fan 11 blows cold air into the static pressure tank 2 to achieve uniformity of the gas temperature and reduction of the flow rate, and then slowly spreads into the air bath cavity 3 through the diffuser plate 24 to achieve the effect of reducing the temperature of the cavity, while the gas flows back to the backflow cavity 1 through the inner circulating air port 5 to achieve the inner circulation of the gas in the air bath temperature control device;

[0113] When 1℃ > e(k) > 0.4℃, the operation power P 电热丝 The inner circulating fan 11 blows hot air into the static pressure tank 2 to achieve uniformity of the gas temperature and reduction of the flow rate, and then slowly spreads into the air bath cavity 3 through the diffuser plate 24 to achieve the effect of increasing the temperature of the cavity, while the gas flows back to the backflow cavity 1 through the inner circulating air port 5 to achieve the inner circulation of the gas in the air bath temperature control device;

[0114] When 0 > e(k) > -0.4℃, the power P 制冷片 The power P 制冷片 is maintained at a low level to maintain the stability of the temperature in the cavity and avoid temperature overshoot.

[0115] When 0.4℃ > e(k) > 0, the power P 电热丝 The power P 电热丝 is maintained at a low level to maintain the stability of the temperature in the cavity and avoid temperature overshoot.

[0116] The input temperature error value E and the temperature error rate ΔE are set. The fuzzy subsets of the language values are {negative large, negative medium, negative small, zero, positive small, positive medium, positive large}, and are simply denoted as {NB, NM, NS, ZO, PS, PM, PB). The error E and the error change rate ΔE are quantified into the region of (-3, 3), and the membership function curve of the input variable is as shown in Figure 3 .

[0117] According to the parameters K p , K i , Kd The impact on the system output characteristics is summarized based on experimental experience, and K is obtained. p K i K d The control rule table is shown in Table 1-3.

[0118] Table 1 K p Fuzzy rule table

[0119]

[0120] Table 2 K i Fuzzy rule table

[0121]

[0122] Table 3 K d Fuzzy rule table

[0123]

[0124] Based on the rule table and the control rules of the air bath incubator, the PID parameter K is... p The following 49 fuzzy control rules are summarized:

[0125] If E=NB and ΔE=NB, then K p =PB,

[0126] If E=NB and ΔE=NM, then K p =PB, ......

[0127] If E = PB and ΔE = PB, then K p =PB,

[0128] E and Ec are fuzzy input variables, K p For fuzzy output variables, NB, PB, NM, etc. are fuzzy sets on the universe of discourse.

[0129] To improve the safety of heating systems, a method of heating with lower power for longer periods is generally adopted. For example... Figure 6 As shown, under ambient temperatures of 36℃ and 60% RH, this device controls the temperature using both conventional PID and fuzzy PID methods. Within one cycle, the response time using fuzzy PID control is approximately 25 seconds shorter than that of conventional PID, and the temperature remains stable at 39℃. Conventional PID control, on the other hand, exhibits overshoot and fluctuates for a period before stabilizing. The results, compared to conventional PID control, demonstrate that the device and method of this invention can reach the target temperature faster and more accurately and maintain long-term stability.

[0130] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as the combination of the technical features does not exist in contradiction, it shall be considered within the scope of the present disclosure.

[0131] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it shall not be understood as a limitation on the patent scope of the present application. It shall be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these shall be within the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. An anaerobic fermentation gas bath temperature control method, characterized by, The application relates to a device for providing a temperature environment for simulating rumen fermentation of ruminants in vitro, simulating anaerobic fermentation of feed in the rumen, and evaluating the digestion of nutritional components of the feed. The backflow cavity, the static pressure cavity and the air bath cavity are sequentially arranged from bottom to top. The backflow cavity comprises an inner circulation fan, a refrigeration module, a heating module, an outer circulation air exchange port and an outer circulation air exchange valve. The static pressure cavity comprises a first temperature sensor, an equal air volume air supply air duct, a flow guide plate and a flow diffuser plate; the first temperature sensor is provided with a plurality of first temperature sensors. The air bath cavity comprises a hanging support plate and a second temperature sensor; the second temperature sensor is provided with a plurality of second temperature sensors; the hanging support plate is provided with adjustable holes for stably placing a reactor, so that the reactor body part is immersed in a stable temperature environment of the air bath cavity and is in close contact with the reactor to form a closed space in the air bath cavity. The second temperature sensor is arranged near the inner circulation air exchange port, and the temperature in the air bath cavity is monitored in real time; the real-time temperature of the outflow gas in the air bath cavity is obtained through a multi-temperature sensor data fusion strategy; and the real-time temperature of the inflow gas in the air bath cavity is obtained through weighted calculation to obtain the real-time temperature in the air bath cavity. The first temperature sensor is provided with a plurality of first temperature sensors which are uniformly arranged near the flow diffuser plate and monitor the temperature of the regulated gas near the flow diffuser plate in real time; the real-time temperature of the air entering the air bath cavity is obtained through a multi-temperature sensor data fusion strategy; and the real-time temperature of the outflow gas in the air bath cavity is obtained through weighted calculation to obtain the real-time temperature in the air bath cavity. The backflow cavity is connected with the static pressure cavity through an inner circulation air inlet, the static pressure cavity is connected with the air bath cavity through the flow diffuser plate, and the air bath cavity is connected with the backflow cavity through an inner circulation air exchange port, so as to form a gas circulation channel, and the left and right sides of the air bath cavity are communicated with the backflow cavity. The inner circulation fan serves as a power component for gas conveying, and the rotating speed of the inner circulation fan can be adjusted intelligently according to different air volume requirements of the static pressure cavity. The flow guide plate is divided into multiple sections, and the deflection angle of each section can be independently adjusted according to the deviation between the temperature values monitored by the temperature sensors. The method comprises the following steps: Step 1: installing each component and checking whether the working state is normal; Step 2, set the target temperature T of the air bath chamber 目标 ; Step 3: dividing different regions in the static pressure cavity and the air bath cavity, arranging a plurality of first temperature sensors and second temperature sensors in each region, cross- verifying the temperature data monitored by different temperature sensors in the same region, calculating the average value of the reliable temperature data in the region as the temperature data of the region, and calculating the real-time temperature as the monitoring temperature in the air bath cavity through the temperature and weight of different regions; Step 4, based on the obtained real-time temperature T of the static pressure chamber 静压 Ambient temperature T 环境 Real-time temperature T of the air bath chamber 气浴 With target temperature T 目标 The relationship, and T 目标 With T 气浴 The difference e(k) is used to jointly select a suitable temperature control strategy; The multi-temperature sensor data fusion strategy comprises the following steps: ①calculating the deviation between multiple temperature sensors in the same region; ， In the formula, D mn is a bias value between different temperature sensors, T m and T n are the monitoring temperature values of the mth and nth temperature sensors, respectively. ②defining the allowable range of the deviation between the temperature sensors in the same region; ， where Dev(m, n) is the temperature value deviation between two sensors, T m and T n are the monitoring temperature values of the mth and nth temperature sensors, respectively. If D mn ≤ Dev(m, n), then D mn Within allowed range; If D mn > Dev(m, n), then D mn is outside the allowed range; If D mn is missing, it is treated as outside the allowed range. ③calculating the temperature value of the region; If D mn The average of all temperature sensors in the area is taken as the result if both are within the allowed range. If D mn If the deviation is not within the allowable range, the sensors whose deviations are outside the range are sequentially judged. If there are a deviations outside the range in the deviation set related to the sensor, where a is a constant greater than half the number of sensors, the sensor is excluded from the current temperature calculation, and the average of the remaining temperature sensors is taken as the result, effectively eliminating the interference of abnormal temperature points and improving the accuracy of the data. ④calculating the temperature value of the air bath cavity through the temperature values of different regions; The temperature weight of the monitored region is determined according to the natural attenuation gradient of the temperature of the gas flow along the flow direction, and the real-time temperature in the air bath cavity is obtained through the temperature and weight of the monitored region in the air bath cavity, ， In the formula, T 气浴腔 is the real-time temperature of the gas bath cavity, 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; 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 ; 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 , the outer circulation ventilation valve and the inner circulation fan are opened simultaneously, the inner circulation fan runs at full power, and the air in the cavity is exchanged with the outside air until |e(k)|<E max or |T 环境 -T 静压 |<t℃, where t is a constant, the outer circulation ventilation valve is closed immediately. ii. When e(k) <-E max and T 环境 > T 静压 , both the cooling fins and the inner circulation fan run at full power to rapidly cool the temperature of the gas in the chamber. ③ When e(k) > E max and T 环境 < T 静压 , both the heating wire and the inner circulating fan run at full power to rapidly increase the temperature of the gas in the cavity. (iv) when -E min e(k) > -E max the operating power P 制冷片 The inner circulating fan blows cold air into the static pressure tank to achieve uniform gas temperature and lower flow rate, and then the air is distributed into the air bath cavity through the diffuser plate to reduce the temperature of the cavity. At the same time, the gas flows back to the return cavity through the inner circulating air port to achieve the inner circulation of the gas in the air bath temperature control device. • when E max > E min the operating power P 电热丝 The inner circulating fan blows the hot air into the static pressure box to realize the uniformity of the gas temperature and the decrease of the flow rate, and then the air is distributed into the air bath cavity through the air distribution plate to realize the function of increasing the cavity temperature, while the gas flows back to the backflow cavity through the inner circulating air port to realize the inner circulation of the gas in the air bath temperature control device. When 0 > e(k) > -E min , the power P 制冷片 of the refrigeration sheet is controlled by the fuzzy pid strategy library, and the P 制冷片 at this time is maintained at a lower level to keep the temperature in the cavity stable and avoid temperature overshoot. When E min >0, the power P 电热丝 of the heating wire is controlled by the fuzzy pid strategy library, and P 电热丝 is maintained at a lower level to keep the temperature in the cavity stable and avoid temperature overshoot.

2. The method of claim 1, wherein, The backflow cavity, the static pressure cavity and the air bath cavity are all provided with a heat preservation layer, which is made of high-efficiency heat insulation material.

3. The method of claim 1, wherein, The refrigeration module comprises a heat-conducting copper plate, a refrigeration sheet, a radiator and a cooling fan, which are used for cooling the regulation gas; the refrigeration sheet is arranged on the side wall of the backflow cavity, and its non-working surface is exposed outside the backflow cavity.

4. The method of claim 1, wherein, The air inlet of the equal air volume air supply air duct is connected with the inner 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 sector and an ellipse, or a regular shape composed of a plurality of small air outlets with the above shapes; the deflection angle is adjusted adaptively according to the deviation between the temperature values monitored by the temperature sensor.

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