Air relative humidity measurement and calibration device

Abstract

The invention discloses an air relative humidity measurement and calibration device, and belongs to the field of humidity measurement. The device is realized by adopting a Dalton partial pressure law, a humid air enthalpy and humidity calculation theory and an improved dry and wet bulb temperature measurement principle, and water vapor is prevented from freely diffusing out of an effective air film through a closed container, so that humid air in the effective air film of the wet bulb sensor is converted into a saturated air state; unsaturated state errors of an effective air film of a traditional dry and wet bulb method are eliminated, meanwhile, a cooling device is added to avoid inaccurate wet bulb measurement caused by the heat transfer limit temperature difference between the dry bulb temperature and the wet bulb temperature, and unification of air humidity measurement, the Dalton partial pressure law, the wet air enthalpy and humidity calculation theory and the related thermodynamic theory is achieved. And a reference point is found for air relative humidity measurement. The method can successfully construct the saturation state of the effective air film around the wet bulb temperature sensor, unifies the theoretical and actual measurement, is excellent in precision, is efficient in calibration, is high in adaptability, and finds a reference point for the measurement of the relative humidity of air.

Description

Technical Field

[0001] This invention belongs to the field of humidity measurement technology, specifically relating to a novel air relative humidity measurement and calibration device that conforms to Dalton's law of partial pressures and the theory of enthalpy and humidity calculation of moist air. Background Technology

[0002] Accurate measurement of humidity parameters is crucial in many fields, including industrial process control, meteorological observation, healthcare, warehousing and logistics, and scientific research. The performance stability and measurement accuracy of the core component—the humidity sensor—highly depend on regular and reliable calibration. Currently, the field of humidity sensor calibration mainly relies on three types of traceable basic methods: dew point method, thermogravimetric method, and saline method.

[0003] However, all three existing humidity sensor calibration techniques have significant limitations and drawbacks in practice.

[0004] Dew point method: Complex and expensive equipment: The high-precision cold mirror dew point meter or precision dew point probe, the highly stable temperature control system, the high-purity gas source, and the complex gas path control result in extremely high purchase and maintenance costs for the entire calibration system. Dependence on condensation judgment and risk of contamination: Cold mirror dew point meters rely on an optical system to detect dew formation, which introduces subjectivity or technical difficulties (especially at ultra-low dew points). Furthermore, the mirror surface is easily contaminated by pollutants in the sample gas, leading to measurement errors or even failure, requiring frequent cleaning and maintenance. Dew point hysteresis: Overcooling may occur during cooling, and there may be a lag in decondensation during heating, affecting measurement accuracy and speed.

[0005] Thermogravimetric analysis: Extremely long measurement cycle: The drying process takes several hours or even longer to achieve stable quality, resulting in low calibration efficiency. Fundamental flaw: Thermogravimetric absorbents cannot completely absorb water vapor from the air. Strict environmental requirements: Extremely high precision is required for the balance, and a highly stable environment is necessary, making it difficult to implement in ordinary laboratories or on-site.

[0006] Saltwater method: Long equilibration time: Achieving stable gas-liquid equilibrium in a closed container can take hours or even days, resulting in slow calibration. Salt solution stability and contamination risk: The saturation of the salt solution must be strictly maintained (no undissolved salt or precipitated salt). The solution is volatile, prone to crystallization, or can contaminate the sensor probe. Long-term use may lead to concentration changes or contamination, requiring frequent replacement and verification.

[0007] Furthermore, existing wet-bulb and dry-bulb humidity measurement methods suffer from a deep-seated contradiction between theory and practice. Dalton's theorem requires that the wet-bulb surface achieve a dynamic equilibrium between evaporation and condensation when the ambient air is saturated, i.e., net mass transfer is zero. However, in actual measurements, the wet bulb is always in an unsaturated quasi-steady state, and its continuous evaporation fundamentally conflicts with the theoretically presupposed local saturation condition. Microscopic mechanism studies show that this contradiction stems from the complex dynamics of the wet-bulb gauze-air interface: water molecules adsorbed on the fiber surface must simultaneously overcome: the binding barrier formed by hydrogen bond networks (inhibiting molecular thermal motion), the high-frequency collision barrier of gas phase molecules (impeding desorption paths), and the energy barrier formed by surface tension (increasing the phase transition activation energy through cohesion). These microscopic effects make it difficult for the gas-liquid interface to reach the theoretical saturation state, causing the classical mass transfer model to fail in describing the dynamic process of an unsaturated effective gas film, ultimately resulting in a systematic deviation of the relative humidity (RH) calculated by traditional formulas from the true atmospheric humidity.

[0008] Forced convection (wind speed 2-10 m / s), widely adopted to suppress measurement errors, while bringing the wet-bulb temperature closer to the theoretical value by disrupting the saturated vapor layer on the wet-bulb surface and enhancing the evaporation rate, introduces new, non-negligible sources of error: First, the forced airflow significantly increases the evaporation flux, directly violating the core premise of the classical isenthalpic humidification model (the idealized assumption that air asymptotically saturates under isenthalpic conditions); second, the continuously disturbed airflow hinders the high-humidity microenvironment around the wet-bulb from reaching thermodynamic equilibrium. This artificial interference with the effective air film's dynamic equilibrium not only causes a systematic deviation between experimental results and theoretical predictions but also results in the measured "relative humidity" essentially representing an unnatural state after wind field disturbance, failing to truly reflect the intrinsic humidity value in the static atmosphere. It is necessary to resolve the contradiction between practice and theory to improve the accuracy and reliability of the wet-bulb and dry-bulb methods. Summary of the Invention

[0009] The present invention aims to at least partially solve one of the technical problems in the aforementioned related technologies.

[0010] Therefore, the purpose of this invention is to provide a novel air relative humidity measurement and calibration device that can successfully construct an effective air film saturation state, and make the air humidity measurement conform to Dalton's partial pressure law, the enthalpy-humidity calculation theory of moist air and a series of related thermodynamic theories, so as to find a benchmark point for air relative humidity measurement, with high accuracy, efficient calibration and strong adaptability.

[0011] To solve the above-mentioned technical problems, the present invention is implemented as follows: This invention provides a novel air relative humidity measurement and calibration device. The device employs Dalton's law of partial pressures, the theory of enthalpy and humidity calculation of moist air, and an improved dry-bulb and wet-bulb temperature measurement principle. By using a sealed container, it prevents water vapor from freely diffusing beyond the effective air film in the traditional dry-bulb and wet-bulb method, enabling the moist air within the effective air film of the wet-bulb sensor to transition to a saturated air state. This eliminates the unsaturated state error of the effective air film in the traditional dry-bulb and wet-bulb method. Simultaneously, the addition of a cooling device avoids the inaccuracy in wet-bulb measurement caused by the thermal limit temperature difference between the dry and wet-bulb temperatures in the traditional method. This achieves a unification of air humidity measurement with Dalton's law of partial pressures, the theory of enthalpy and humidity calculation of moist air, and a series of related thermodynamic theories, providing a benchmark for air relative humidity measurement.

[0012] In addition, the novel air relative humidity measurement and calibration device according to the present invention may also have the following additional technical features: In some embodiments, the apparatus includes: The sealed container 4 is configured to prevent water vapor from freely diffusing outside the effective gas film in the conventional wet-bulb method, so that the humid air in the effective gas film of the wet-bulb sensor will change to a saturated air state. A wet-bulb temperature sensor 1 is installed inside the sealed container 4 to measure the temperature after the water evaporates and absorbs heat, causing the temperature to drop. Dry-bulb temperature sensor 2 is arranged side by side and at the same height as wet-bulb temperature sensor 1 inside the sealed container 4, and is used to reflect the thermodynamic intrinsic temperature of air. The temperature control system is configured to ensure that the humid air inside the effective air film forms a saturated state that conforms to Dalton's law of partial pressure and the enthalpy-humidity calculation theory of humid air. It is a real-time control system that regulates the conditions for the humid air to reach a saturated state.

[0013] In some of these embodiments, the temperature control system includes a humid air temperature control system inside a sealed container (a sealed container microenvironment temperature control system) and a wet-bulb water supply temperature control system; The sealed container microenvironment temperature control system is configured to accurately control the internal temperature of the sealed container 4; the wet-bulb water supply temperature control system is configured to control the water supply temperature of the wet-bulb temperature sensor 1, that is, the water temperature of the water inlet tank.

[0014] In some embodiments, the closed container microenvironment temperature control system includes insulation cotton 5, a closed container microenvironment cooling coil 8, a data acquisition controller 12, and a buffer water tank 7; the insulation cotton 5 surrounds the outer periphery of the closed container 4, the closed container microenvironment cooling coil 8 is wound around the inner wall of the closed container 4 and connected to the buffer water tank 7, and can control the temperature of the environment inside the closed container 4 by controlling the flow of cooling water in the buffer water tank 7 within the closed container microenvironment cooling coil 8 under the action of the data acquisition controller 12.

[0015] The insulation cotton 5 and the microenvironment cooling coil 8 of the sealed container are used to maintain a constant air temperature inside the sealed container and play a role in heat insulation and constant temperature. They can also be replaced by immersion cooling, vacuum chamber, sleeve foaming and other methods.

[0016] In some embodiments, the inner surface of the insulation cotton 5 is provided with an ambient temperature sensor 3, which, together with the ambient air temperature sensor 19 and the dry bulb temperature sensor 2 inside the sealed container, determines in real time the degree of influence of the external ambient temperature on the sealed container.

[0017] In some embodiments, the wet-bulb water supply temperature control system includes a water inlet trough 6, a weather wet-bulb gauze 11, a water inlet cooling coil 9, a data acquisition controller 12, and a buffer water tank 7. The water inlet trough 6 is connected to the wet-bulb temperature sensor 1 via the weather wet-bulb gauze 11. The water inlet trough 6 is connected to the water inlet cooling coil 9, and the water inlet cooling coil 9 is connected to the buffer water tank 7. Under the action of the data acquisition controller 12, the system can control the temperature of the wet-bulb water supplied in the water inlet trough 6 by controlling the flow of cooling water in the buffer water tank within the water inlet cooling coil 9.

[0018] In some embodiments, the wet-bulb temperature sensor 1, the dry-bulb temperature sensor 2, the ambient temperature sensor 3, the buffer water tank temperature sensor 17, the water inlet tank temperature sensor 18, and the ambient air temperature sensor 19 are all connected to the data acquisition controller 12, and then transmit the data to the host computer. The host computer uses the measurement data from the wet-bulb temperature sensor 1, the dry-bulb temperature sensor 2, the ambient temperature sensor 3, the buffer water tank temperature sensor 17, the water inlet tank temperature sensor 18, and the ambient air temperature sensor 19 to stabilize and regulate the air inside the sealed container 4, and finally calculates the initial relative humidity of the air based on the data from the wet-bulb temperature sensor 1 and the dry-bulb temperature sensor 2.

[0019] In some embodiments, the diameter of the sealed container 4 is determined as follows: Based on the kinetic theory of molecules and the theories of diffusion and energy conservation, the volumes of sensors of different shapes and sizes, as well as the wet-bulb gauze 11, were calculated to obtain the volume of the sealed container. Then, according to the isotropic theory, the installation positions of the wet-bulb temperature sensor 1 and the dry-bulb temperature sensor 2 were determined. Based on the calculated diffusion characteristics of water molecules after evaporation, the farthest limiting diffusion distance was obtained, and this distance was taken as the diameter of the sealed container.

[0020] In some embodiments, the wet-bulb temperature sensor 1 includes a temperature sensor and a wet-bulb gauze 11. The wet-bulb gauze 11 covers the temperature sensor head in a single layer. A hollow sleeve 16 is arranged between the lower part of the wet-bulb sensor and the center hole at the bottom of the sealed container to wrap the wet-bulb gauze and extend downward into the water inlet tank to contact and connect with water, so as to continuously supply water to the wet-bulb. This ensures that only the moisture content of the wet-bulb gauze wrapping the wet-bulb temperature sensor 1 evaporates into the sealed container, preventing excessive evaporation from causing the wet-bulb temperature to be too high.

[0021] In some embodiments, the wet-bulb temperature sensor 1, the dry-bulb temperature sensor 2, the ambient temperature sensor 3, the buffer tank temperature sensor 17, the water inlet tank temperature sensor 18, and the ambient air temperature sensor 19 are resistance / voltage / current type temperature sensors or mercury thermometers; the data acquisition controller 12 (PLC controller / industrial control board / microcontroller); the closed container microenvironment circulation pump 14; and the water inlet tank circulation pump 15 are also included. The wet-bulb temperature T is measured. w The temperature of buffer tank 7 (T1), water inlet tank 6 (T2), and sealed container 4 (T3) are recorded. The data acquisition controller 12 (PLC controller / industrial control board / microcontroller) collects the real-time temperature T2 of the water inlet tank through electronic sensors with a sampling period of 1 second and calculates the temperature difference ΔT=T2. T w The system is set to open when ΔT > 0.1℃ and T2 ≤ T. w +0.05℃ and T3≤T w The 0.05℃ hysteresis dual-threshold mechanism, which stops at +0.05℃, determines the opening threshold based on the effective water volume V of the sealed container 4 and the water inlet 6, and the circulation pump flow rate q. v and the system time constant τ=V / q v The adaptive start-up time calculation formula t is derived from the first-order exponential cooling model. on =τ ln(ΔT / 0.05) is used to calculate the theoretical start-up time t of the circulating pump. on After the circulating pump is turned on, a decrementing timer is started, with T2 ≤ T. w +0.05℃ and T3≤T wA +0.05℃ early shutdown and a normal shutdown upon timer reset serve as dual interruption conditions. τ is the core dynamic parameter determining the system's temperature response speed. Ultimately, this achieves heat exchange equilibrium between the water inlet tank T2, the microenvironment temperature, and the sealed container T3, bringing their temperatures close to the wet-bulb temperature T. w .

[0022] Compared with the prior art, the present invention has at least the following beneficial effects: In this embodiment of the invention, a novel air relative humidity measurement and calibration device that fully conforms to Dalton's law of partial pressures and the theory of enthalpy and humidity calculation of moist air is provided. The measurement accuracy is supported by thermodynamic theory and can be used as a calibration device for air relative humidity measurement technology. By using a rigid sealed container to constrain water vapor to diffuse towards the outer boundary of the effective air film (ambient air), the humid air inside the effective air film is forced to approach the saturation state (φ=100%). This solves the core contradiction between the theoretical assumptions of the traditional wet-bulb method and the actual measurement, completely eliminates the systematic errors caused by the unsaturated state of the effective air film and forced convection. The measured value is supported by Dalton's law of partial pressures, the theory of enthalpy and humidity calculation of moist air and a series of related thermodynamic theories that have been used for more than 200 years, and is highly consistent with the true humidity eigenvalue. In this embodiment of the invention, the novel air relative humidity measurement and calibration device provides a balance between economy and efficiency: it eliminates the need for expensive and precision equipment for the dew point method and high-precision balances for the thermogravimetric method. The structure consists of a sealed container, conventional sensors, a cooling circuit, and a temperature control system, resulting in low purchase and maintenance costs. It avoids the long balancing / drying process of the thermogravimetric method and the brine method, significantly improving calibration efficiency and eliminating the need for complex environmental control. In this embodiment of the invention, the novel air relative humidity measurement and calibration device is highly reliable and adaptable: the sealed design reduces the risk of sensor probe contamination, and problems such as salt solution evaporation and crystallization are eliminated; the independent cooling circuit and insulation design ensure stable operation in ordinary laboratories or measurement sites, without the need for harsh environmental conditions, making it applicable to a wider range of scenarios.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the air relative humidity measurement and calibration device disclosed in one embodiment of the present invention; Figure 2 This is a top view schematic diagram of an air relative humidity measurement and calibration device disclosed in an embodiment of the present invention; Figure 3 This invention discloses conventional wet-bulb and dry-bulb temperature measurement data; Figure 4This is relative humidity measurement data disclosed in one embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures: 1-Wet-bulb temperature sensor; 2-Dry-bulb temperature sensor; 3-Ambient temperature sensor; 4-Sealed container; 5-Insulation cotton; 6-Water inlet tank; 7-Buffer water tank; 8-Sealed container microenvironment cooling coil; 9-Water inlet tank cooling coil; 10-Flow meter; 11-Wet-bulb weathering gauze; 12-Data acquisition controller; 13-Thermostatic unit; 14-Sealed container microenvironment circulation pump; 15-Water inlet tank circulation pump; 16-Hollow sleeve; 17-Buffer water tank temperature sensor; 18-Water inlet tank temperature sensor; 19-Ambient air temperature sensor. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and specific examples and application scenarios.

[0028] This invention addresses the theoretical and practical discrepancies caused by the unsaturated state of the effective gas film in traditional wet-bulb and dry-bulb measurements by innovatively proposing a rigid container-constrained effective gas film boundary control device. By designing a specially rigid, sealed container, a closed system is constructed at the effective gas film interface of the wet-bulb sensor, forcibly restricting water vapor diffusion only into the moist air inside the sealed container. This spatial constraint significantly inhibits gas diffusion flux, forcing the water molecule concentration in the moist air within the effective gas film surrounding the wet bulb to continuously accumulate until thermodynamic saturation (φ=100%) is reached. Experimental verification revealed fogging on the inner surface of the sealed container; this phase transition directly confirms that the sealed container can construct a saturated effective gas film—a phenomenon that contrasts sharply with the evaporation-absorption-escape process of unsaturated effective gas films in traditional open environments. The wet-bulb temperature value measured under this saturated state is in high agreement with the predicted value of the isenthalpic humidification theory. For the first time in a real measurement scenario, it is possible to achieve the result without thermodynamic theory assumptions. That is, it can be consistent with Dalton's law of partial pressures, the theory of enthalpy and humidity calculation of moist air and a series of related thermodynamic theories that have been used for more than 200 years, and is in high agreement with the eigenvalue of real humidity. This fundamentally solves the principle and systematic error problem caused by the unsaturation of the open effective air film.

[0029] The structural principle of the device of the present invention is as follows: Figure 1 and Figure 2As shown, its core components include a wet-bulb temperature sensor 1, a dry-bulb temperature sensor 2, an ambient temperature sensor 3, a sealed container 4, insulation cotton 5, a water inlet trough 6, a buffer water trough 7, a sealed container microenvironment cooling coil 8, a water inlet trough cooling coil 9, a flow meter 10, a weather wet-bulb gauze 11, a data acquisition controller 12, a constant temperature unit 13, a sealed container microenvironment circulation pump 14, a water inlet trough circulation pump 15, a hollow sleeve 16, a buffer water trough temperature sensor 17, a water inlet trough temperature sensor 18, and an ambient air temperature sensor 19.

[0030] 1. Sealed container design A sensor-sealed container 4 is provided to achieve sealed protection and stable assembly of a wet-bulb temperature sensor 1 and a dry-bulb temperature sensor 2. The housing components of this structure are made of materials such as acrylic, polyvinyl chloride (PVC), or metal, which are impermeable to air molecules and possess dense barrier properties. They are processed into cylindrical, spherical, or other shapes that facilitate sealing and sensor installation according to preset structural dimensions. The sealed housing simultaneously serves as the sensor's mounting base and protective component, providing stable installation positioning and assembly support for the sensor. Furthermore, its material and sealing shape ensure the sensor's airtight protection, guaranteeing sensor assembly reliability and a sealed working environment.

[0031] 2. Sensor sealing and supporting structure setup To address the temperature control and protection requirements of the sealed container 4 and the cooling requirements of this calibration device, this technology specifically configures a composite structure for cooling and thermal insulation. The cooling system includes various optional cooling implementation methods, including independently deployed sealed container microenvironment cooling coils 8, and immersion cooling structures. Immersion cooling can utilize heat exchange media including water, fluorinated liquids, and other liquid heat exchange media with high specific heat capacity, achieving continuous heat exchange and cooling through the cooperation of the media and cooling components.

[0032] The matching sealed container microenvironment cooling coil 8 is made of metal materials with excellent thermal conductivity. Optional materials include copper, aluminum, and aluminum alloys. By selecting high thermal conductivity materials, heat transfer efficiency is ensured, meeting the rapid response requirements of temperature control and adapting to the working requirements of the overall temperature control system.

[0033] The placement of the aforementioned closed-environment cooling coil 8 can be adjusted according to the material properties of the closed container: Under normal operating conditions, the closed-environment cooling coil 8 is installed internally, directly contacting the internal environment of the closed container 4 or the target heat exchange surface for heat exchange; for closed containers 4 with high thermal conductivity and excellent thermal conductivity, the closed-environment cooling coil 8 can be placed outside the container. The closed-environment cooling coil 8 must be tightly attached to the outer wall of the closed container 4, and thermal grease should be evenly applied between the closed-environment cooling coil 8 and the wall of the closed container 4 to minimize the heat transfer gap, improve heat exchange efficiency, ensure the uniformity of temperature control of the internal environment of the closed container, provide a stable temperature working environment for the dry and wet bulb temperature sensors, and simplify the internal structure layout.

[0034] Cooling can also be achieved through an immersion-type temperature control method, which involves immersing the entire intermediate layer closed system in water, fluorinated liquid, or other heat exchange medium with a large specific heat capacity. By adjusting the temperature of the heat exchange medium, the temperature of the intermediate layer closed space can be controlled. This method can improve the stability of temperature control by relying on the specific heat capacity advantage of the heat exchange medium.

[0035] Cooling can also be achieved using an air-cooled temperature control method. This is accomplished by placing heat dissipation fins (made of high thermal conductivity materials such as aluminum or aluminum alloy) on the outside of the enclosed middle layer structure, along with a miniature cooling fan. The fan accelerates heat exchange between the fins and the air, removing heat from the enclosed system. This method is suitable for scenarios with limited space and where liquid media is not required. It can be linked with existing controllers to automatically start and stop the fan and adjust its speed based on temperature thresholds. The structure is simple and easy to maintain.

[0036] Based on the cooling structure, this technology designs four types of differentiated thermal insulation structures to block the ingress of external heat and maintain internal temperature stability: The first type is the sleeve-filled insulation structure, which adopts a combination of inner and outer double sleeves. A filling cavity is reserved between the two sleeves, and the cavity is filled with conventional insulation materials such as rock wool, glass wool, and polyurethane foam. Thermal barrier is achieved by relying on the porous insulation properties of the filling material. The second type is an external adhesive insulation structure, in which flexible insulation cotton material is directly adhered to the outer wall of the sealed container 4. The cotton material is tightly bonded to the outer wall of the container to form a continuous insulation layer. It is easy to construct and adaptable to sealed containers of various shapes. The third type is a vacuum cavity insulation structure, which constructs a vacuum cavity layer around the sealed container 4 through sealing processing. It utilizes the vacuum environment to significantly reduce the efficiency of gas heat conduction and heat convection, and its insulation performance is superior to that of conventional filling materials. The fourth type is the thermal insulation coating structure, which uniformly coats a polymer thermal insulation coating on the outer surface of the sealed container 4. After curing, a thin thermal insulation film is formed. This structure does not require a significant increase in the outer diameter of the structure and can effectively reduce the overall structural volume while achieving the thermal insulation function.

[0037] 3. Water intake channel design This water-guiding trough 6 is used to facilitate the water-guiding function of the wet-bulb gauze 11. Its main structural design, processing technology, and compatible materials are consistent with the aforementioned closed environment design method. The key difference is that this water-guiding trough 6 does not employ a closed design; its upper end is designed as an open structure, or a small hole is pre-drilled at the top. This structural design adapts to the water-guiding process of the wet-bulb gauze 11, providing a stable water-guiding channel and ensuring smooth water guiding. Simultaneously, relying on the main structural design consistent with the closed environment, it achieves stable installation and structural reliability. The water-guiding trough and the closed environment are installed vertically, with the distance between the lower end face of the sealed container 4 and the upper end face of the water-guiding trough 6 not exceeding 1 cm.

[0038] The cooling coil 9 is installed inside the water inlet trough 6, and the design method is the same as that of the cooling coil 8 for the microenvironment inside the sealed container 4.

[0039] A water inlet temperature sensor 18 is installed inside the water inlet tank 6.

[0040] The thermal insulation component is selected from one or more of the following: a sleeve-type filled thermal insulation material structure, a container outer wall insulation cotton pasted structure, a vacuum cavity thermal insulation structure, and a thin-layer thermal insulation structure with thermal insulation coating on the container outer wall. The thermal insulation coating structure can reduce the overall structural volume while achieving thermal insulation. The specific method is as described in the closed container thermal insulation structure.

[0041] 4. Sensor Installation Method After the wet-bulb temperature sensor 1 and the dry-bulb temperature sensor 2 are assembled into the aforementioned cylindrical enclosed housing, the connection between the sensor and the enclosed housing is sealed with air sealant to ensure the overall sealing performance of the enclosed structure and provide a reliable sealed protective environment for the sensors. For the wet-bulb temperature sensor 1, a single layer of special meteorological wet-bulb gauze 11 is wrapped around its outer periphery, and a hollow sleeve 16 with a length of 2cm (materials with a thermal conductivity lower than copper can be used) is fitted onto the lower end of the meteorological wet-bulb gauze 11. This assembly structure can, on the one hand, facilitate water diversion in subsequent deployment, and on the other hand, effectively prevent the evaporation of moisture within the 2cm section of meteorological wet-bulb gauze 11 covered by the hollow sleeve 16, ensuring the stability of the detection environment for the wet-bulb temperature sensor 1 and the dry-bulb temperature sensor 2, and ensuring the accuracy of the detection data.

[0042] A 3mm diameter through hole is made at the bottom of the cylindrical closed shell. The diameter of the through hole is set to fit the size through which the wet-bulb gauze 11 passes. This ensures that the wet-bulb gauze 11 can be smoothly inserted and laid out, and also prevents the sealing performance of the closed shell from being damaged due to the through hole being too large, thus taking into account both the ease of installation and the reliability of sealing.

[0043] All five temperature sensors are PT100 temperature sensors.

[0044] The signal collected by the temperature sensor is transmitted in real time to the data acquisition controller 12 and the host computer via the data acquisition device, so as to accurately control the temperature of the constant temperature water bath and the water inlet tank. When the wet-bulb temperature and the dry-bulb temperature are equal, it can be determined that the sealed container 4 is in a saturated state, and the wet-bulb temperature obtained at this time is the result.

[0045] Wet-bulb temperature sensor 1 and dry-bulb temperature sensor 2, as key measuring elements of the device, continuously monitor the temperature parameters in the sealed microenvironment (i.e., the sealed container 4). This real-time data is used to determine the system's thermal equilibrium state and also provides the foundation for the novel relative humidity tracing algorithm proposed in this invention. The internal environment of the sealed container 4 is cooled as a whole by cooling fluid, while the water inlet tank 6 is specifically designed for temperature control along the wet-bulb water supply path. Two independent cooling coils (the sealed container microenvironment cooling coil and the water inlet tank cooling coil) are connected to the data acquisition controller 12, and the two tanks are precisely temperature-controlled through a preset temperature adjustment program. The buffer tank 7 serves as an auxiliary cold source to supply cooling fluid to the two cooling coils, ensuring stable system operation under high-temperature conditions. This integrated structure, through coordinated temperature management, creates the necessary conditions for establishing a saturated state of the effective gas film around the wet bulb that conforms to thermodynamic theory. The buffer tank 7 is equipped with a buffer tank temperature sensor 17.

[0046] 5. Temperature control device design To achieve temperature control, the temperature of the sealed container 4 and the water tank 6 is controlled by a coolant circulation structure. Specifically, the sealed container microenvironment circulation pump 14 and the water tank circulation pump 15 are set as the power source for coolant circulation. After the sealed container microenvironment circulation pump 14 and the water tank circulation pump 15 are started, they deliver the coolant from the buffer water tank 7 to the sealed container microenvironment cooling coil 8 and the water tank cooling coil 9, respectively. The coolant flows continuously along the coil pipes and exchanges heat with the air in the sealed container 4. The temperature of the air in the sealed container 4 is regulated through heat transfer, which meets the temperature adaptation requirements of the wet bulb temperature sensor 1 and the dry bulb temperature sensor 2. The temperature of the buffer water tank 7 is controlled by the constant temperature unit 13. The selected coolant has good compatibility with the coil material and air, and is suitable for the temperature control range, avoiding problems such as corrosion and heat exchange failure.

[0047] To achieve automatic and precise temperature control and reduce manual intervention, an automatic control module is added to construct a complete closed-loop temperature control system: a temperature sensor is fixedly installed at a corresponding position in the water inlet tank. This temperature sensor continuously collects the actual temperature signal of the purified water, converts it into an electrical signal, and transmits it to the data acquisition controller 12. The data acquisition controller 12 has a preset temperature threshold and a dedicated control algorithm adapted to the sensor's operation. It accurately compares and analyzes the received actual temperature data with the preset temperature threshold to determine whether the current temperature deviates from the preset range. If there is a deviation, it determines the adjustment direction and adjustment range, thereby triggering the corresponding control action to ensure that the temperature of the purified water in the sealed container and the water inlet tank is maintained within the preset range, ensuring the temperature stability of the environment detected by the wet and dry bulb temperature sensors.

[0048] This temperature control device is compatible with the data acquisition of the aforementioned wet-bulb temperature sensor 1, dry-bulb temperature sensor 2, ambient temperature sensor 3, buffer water tank temperature sensor 17, water inlet tank temperature sensor 18, ambient air temperature sensor 19, and flow meter 10; it is also compatible with the temperature regulation of the sealed container 4, insulation cotton 5, and water inlet tank 6, ensuring the stability of the detection environment of wet-bulb temperature sensor 1 and dry-bulb temperature sensor 2. It adopts a variety of cooling methods that can be selected as needed, and with the cooling medium circulation structure and automatic closed-loop control module, it can realize temperature adaptation and regulation under different working conditions.

[0049] 1. Compression refrigeration unit The refrigeration device is constructed using a compression refrigeration circuit, including a compressor, condenser, throttling element, and evaporator. The compressor drives the refrigerant to circulate and undergo phase change within the circuit, and the evaporation of the refrigerant absorbs heat to achieve the refrigeration function. The evaporator is adapted to the cooling medium circulation system to transfer the cooling capacity to the cooling medium, and then completes heat exchange with pure water in the water tank through the coil to achieve temperature control, adapting to scenarios with a wide range of temperature regulation and high refrigeration power requirements.

[0050] 2. Semiconductor-based cooling A thermoelectric cooling chip (based on the principle of thermoelectric cooling) is used as the core cooling component. The thermoelectric cooling chip is tightly attached to the wall of the aforementioned cylindrical enclosed shell, and directional cooling is achieved by relying on the Peltier effect. The cold end of the thermoelectric cooling chip is attached to the wall of the enclosed shell to absorb heat from the enclosed system and the water tank. The hot end is equipped with a heat dissipation structure (such as a combination of fins and a fan) to quickly dissipate the heat generated during the cooling process and avoid heat accumulation at the hot end affecting the cooling efficiency. By linking with the data acquisition controller 12, the cooling power of the thermoelectric cooling chip can be precisely adjusted to achieve fine temperature control, adapt to low temperature control requirements and miniaturized enclosed structure, and eliminate the need for refrigerant, thus avoiding the risk of refrigerant pollution and improving the environmental friendliness of the device.

[0051] 3. Evaporative cooling Cooling is achieved using the principle of evaporative cooling. A highly absorbent heat-dissipating cotton is completely wrapped around the outside of a cylindrical, enclosed shell, and a controllable water supply device is installed to continuously and quantitatively replenish the cotton. The evaporation of moisture within the cotton absorbs heat from the enclosed system and the water inlet, thus lowering the temperature. To prevent excessive humidification from causing abnormal humidity within the enclosed structure and affecting the normal operation of the sensors, a humidity detection element is added, which works in conjunction with the data acquisition controller 12 to monitor ambient humidity in real time and adjust the water supply to precisely control the moisture content of the heat-dissipating cotton. This cooling method is suitable for high-temperature and low-humidity conditions, offering advantages such as low cost and low energy consumption, making it suitable for low-cost applications.

[0052] 6. Temperature control method Temperature control in this technology is achieved through a cooling medium circulation method. A circulation pump is used as the power source to deliver the cooling medium to the aforementioned cooling coil. During the continuous flow of the cooling medium in the coil, it exchanges heat with the air in the sealed container microenvironment and the pure water in the water tank. The temperature of the air in the sealed container microenvironment and the pure water in the water tank is adjusted through heat transfer to meet the temperature environment requirements for sensor operation.

[0053] To achieve automatic and precise temperature control, an automatic control module is added to form a closed-loop temperature control system: an ambient temperature sensor 3, a water inlet temperature sensor 18, and an ambient air temperature sensor 19 are respectively installed on the inner wall of the insulation cotton 5, inside the water inlet 6, and on the ambient air side. These sensors are used to collect real-time temperature data of the inner wall of the insulation cotton, the ambient air temperature, and the purified water temperature, and the collected temperature data is synchronously transmitted to the data acquisition controller 12. The data acquisition controller 12 has a built-in preset temperature threshold and a matching control algorithm. After receiving the actual temperature data, it compares and analyzes it with the preset temperature threshold to determine whether a temperature adjustment action needs to be initiated, and determines the adjustment direction and adjustment range to ensure the accuracy and stability of temperature control.

[0054] In this embodiment, a PT100 temperature sensor is used for temperature monitoring, with the temperature T1 of the buffer water tank 7 serving as the constant-temperature cold source (the set temperature is the wet-bulb temperature T). w The closed-loop control system is constructed by actively controlling the water inlet tank temperature T2 and the closed-loop container microenvironment temperature T3 through the closed container microenvironment circulation pump 14 and the water inlet tank circulation pump 15, respectively. This ultimately achieves heat exchange balance between the water inlet tank temperature T2, the closed-loop container microenvironment temperature T3, and the closed container 4, making the internal ambient temperature of the closed container 4 approach the wet-bulb temperature T. w Its core control logic and operation process are as follows: The data acquisition controller 12 uses a fixed sampling period to perform periodic temperature control. The sampling period is set to 1 second. After each control cycle starts, the PLC controller (industrial control board / microcontroller) collects the temperature T2 of the water inlet 6 in real time through the water inlet temperature sensor 18, and calculates the real-time temperature difference ΔT. The temperature difference calculation formula is ΔT=T2-T w Simultaneously, the data acquisition controller 12 acquires the microenvironment temperature T3 of the sealed container in real time and calculates the real-time temperature difference ΔT. The formula for calculating the temperature difference is ΔT = T3 - T. w T w This refers to the wet-bulb temperature. To prevent the water inlet circulation pump 15 and the closed container microenvironment circulation pump 14 from frequently starting and stopping near the threshold, a hysteresis control dual-threshold triggering mechanism is set, wherein the cooling start threshold is T2>T. w +0.1℃ and T3>T w +0.1℃ (i.e., ΔT>0.1℃), the cooling stop threshold is T2≤T w +ε and T3≤T w +ε, where ε is 0.05℃, forms a hysteresis width of 0.05℃, ensuring the stability of system operation.

[0055] When ΔT > 0.1℃ is detected, the data acquisition controller 12 triggers the entry into active cooling mode. At this time, the volume of the water inlet tank 6 or the sealed container 4 is V (unit: m³), ​​and the fixed volume flow rate q of the water inlet tank circulation pump 15 or the sealed container microenvironment circulation pump 14 is used. v (Unit: m³ / s), calculate the system characteristic time constant τ = V / q v (Unit: s), and using a first-order exponential cooling model, the theoretical opening time t required to cool the temperature T2 of the water inlet tank 6 and the microenvironment temperature T3 of the sealed container from the current temperature to the target equilibrium zone is calculated. on The physical basis of this first-order exponential cooling model is the energy conservation equation under isothermal cold source conditions, specifically expressed as:

[0056] After simplification, we get:

[0057] The analytical solution to this differential equation is:

[0058] The formula for calculating the adaptive on-time is obtained from the inverse solution of the analytical solution:

[0059] The above-mentioned start-up time calculation has adaptive characteristics, that is, t onThe system dynamically adjusts based on the real-time temperature difference ΔT: when the initial temperature difference is large, the start-up time is automatically extended to ensure rapid cooling; if the temperature difference increases due to external thermal disturbances, the start-up time will automatically adapt and be extended during the next control cycle recalculation; if the temperature difference is close to ε, only a short pulse is needed to maintain temperature balance. After the water tank circulation pump 15 or the closed container microenvironment circulation pump 14 is turned on, the data acquisition controller 12 (PLC controller / industrial control board / microcontroller) starts a decrementing timer, and simultaneously monitors the water tank 6 temperature T2 and the closed container microenvironment temperature T3 in each subsequent 1-second sampling cycle, setting dual interruption shutdown conditions to achieve both energy saving and precise temperature control: firstly, if T2≤T w +ε or T3≤T w +ε immediately interrupts the decrementing timer and shuts down the circulation pump in the corresponding water tank, achieving early shutdown and energy-saving operation; secondly, if the decrementing timer counts to zero, the corresponding circulation pump shuts down normally, completing this cooling cycle.

[0060] After the corresponding circulation pump shuts down, the system returns to temperature monitoring mode, waiting for the next sampling cycle to start. The entire control cycle is continuously repeated at 1-second intervals. Key parameters of this closed-loop control system include: the effective water volume V of the water inlet tank 6, the microenvironment temperature T3 of the sealed container, and the rated flow rate q of the water inlet tank circulation pump 15 and the sealed container microenvironment circulation pump 14. v Cold source set temperature T w Stopping threshold ε (0.05℃), system characteristic time constant τ=V / q v The sampling period Δt = 1s, where the system characteristic time constant τ is the core dynamic parameter, directly determining the response speed of the system temperature control. Through a closed-loop cycle of "monitoring-triggering-calculation-execution-interruption", dynamic adaptive adjustment of the temperature T2 of the water inlet tank 6 and the microenvironment temperature T3 of the sealed container is achieved. Furthermore, through continuous heat exchange between T2, T3 and the air inside the sealed container, the overall system temperature is driven to approach and slightly exceed the wet-bulb temperature T. w This ensures the temperature stability of the environment detected by wet-bulb temperature sensor 1 and dry-bulb temperature sensor 2.

[0061] The theoretical calculations for the closed structure of this invention are explained below.

[0062] The water in the wet-bulb gauze evaporates, causing the water molecules around the gauze to cool down. The latent heat of evaporation equals the sensible heat of the water molecules cooling down. According to the law of conservation of energy: , in ; ; .

[0063] The calculation is performed under the condition of t=25°C and RH=50%, where the initial temperature is: Initial moisture content Final wet-bulb temperature: At this point, the air in the sealed container is saturated, RH=100%, and the final moisture content is... .

[0064] The diameter of the spherical temperature sensing bulb is 1.1 cm, and a 0.3 mm thick wet-bulb gauze is wrapped around its outside. According to the spherical ring calculation formula, the volume of the wet-bulb gauze is 0.1203 cm³, which is approximately all water, i.e., the total mass is 0.1203 g.

[0065] The experiment measured the mass of a roll of dry wet-bulb weathering gauze to be 6.0g; after absorbing water, its mass was 21.0g. Therefore, the mass of water accounts for: ; At this moment, the mass of water in the wet-bulb gauze is: ; Substituting the calculation result into the above formula, we get: .

[0066] Based on the diffusion properties of water molecules, in a sealed container, the wet-bulb sensor's temperature-sensing bulb is positioned 2cm above the ground, and equidistant from the top and surrounding walls of the container, to ensure better diffusion of water molecules. , in, We can solve for: ;

[0067] The calculations show that a cylinder with a base radius of 3.9 cm and a height of 5.9 cm can be used as a sealed container, or a container with a volume of 283 cm³ can be selected. 3 Spheres, etc. This calculation method lays the foundation for the design of the rigid container dimensions in this invention.

[0068] The derivation of the formula for calculating relative humidity is explained below: Physical principle: Wet-bulb cooling is caused by the latent heat of vaporization of liquid water. According to the law of conservation of energy, the heat released during wet-bulb cooling is equal to the heat absorbed by the evaporation of water.

[0069] Basic heat balance equation: , in: The specific heat capacity of mercury, For the mass of mercury, The change in temperature For the mass of evaporated water, It is the latent heat of vaporization of water.

[0070] Parameter expansion: Mercury mass: The mass of evaporated water (caused by the increase in air humidity): Air quality: .

[0071] Simultaneous expressions: .

[0072] Due to the above coefficients Since all of them are known constants, we can conclude that:

[0073] That is, the change in wet-bulb temperature is directly proportional to the change in air humidity.

[0074] As known from the above formula, through the change of wet-bulb temperature This allows us to infer the changes in air humidity during the process. .

[0075] Each air change results in the following microenvironmental change process: Initial state 0: Dry bulb temperature wet-bulb temperature Given, moisture content unknown.

[0076] State 1: Wet-bulb temperature Dry bulb temperature Given, moisture content unknown.

[0077] Relationship: Note: In this equation and All of these are unknowns and cannot be solved at the moment.

[0078] Continuous state derivation: Similarly, from state 1 to state 2, and then to state... :

[0079]

[0080]

[0081] Conclusion: Each additional state... This will introduce a new unknown variable. .

[0082] When the microenvironment reaches its final equilibrium state (i.e., the air becomes saturated): .

[0083] At this point, the new variable introduced in the final state Since the air is known to be saturated at this point, that is... At the same time, it is known The temperature, then , , The saturated vapor pressure is then calculated using the Antoine Equation. :

[0084] (in Calculate the final moisture content using Dalton's law of partial pressures (assuming the values ​​are constants). :

[0085] Due to the final state Given that the aforementioned series of proportional relationships can be used to deduce the initial moisture content, we can ultimately obtain it. .

[0086] Given the initial dry-bulb temperature and the obtained moisture content The relative humidity in that environment can then be calculated. Thus, the relationship between each air change was obtained.

[0087]

[0088] The experimental design is explained below.

[0089] The experiment uses a sealed container 4 as the main body, and external insulation cotton 5 and a buffer water tank 7 are used to cool the dry bulb temperature inside the sealed container to reduce the temperature difference between the dry and wet bulbs, ensuring that the wet bulb temperature continues to decrease until the air inside the sealed container 4 is saturated. Table 1 lists the main equipment of the experimental system.

[0090] Table 1 Main Material and Device Parameters

[0091] A wet bulb is placed in a sealed container, and the initial humidity and temperature are controlled. By adjusting these parameters, the changes in the system's behavior are observed.

[0092] This experiment used pre-calibrated PT100 temperature sensors to measure the wet-bulb temperature, dry-bulb temperature, water temperature in the water inlet tank, water temperature in the buffer tank, the inner wall temperature of the insulation cotton, and the ambient air temperature within a sealed container. The wet-bulb temperature sensor's sensing head was wrapped in a single layer of clean, breathable wet-bulb gauze and allowed to hang naturally to ensure the evaporation process was not affected by the gauze's thickness. A water bottle meeting the calculated volume and diameter requirements was used as the sealed device. Its bottom was sealed to a hollow sleeve 16 with PP glue. Holes were made at corresponding positions on the upper surface of the sealed container to vertically insert two temperature sensors. The sensor measuring the dry-bulb temperature was positioned between the breathable wet-bulb gauze and the sealed container wall. The sensing parts of both sensors were kept at the same height, with the dry-bulb temperature sensor suspended in the middle of the container to avoid contact with the bottle wall or bottom, thus accurately reflecting the internal air temperature. A 0.5mm diameter hole is drilled in the center of a sealed container, and a 2cm high hollow sleeve 16 is installed. Wet-bulb gauze passes through the hollow sleeve 16 and the hole in the sealed container. The size of the sleeve and the hole is precisely controlled to allow a single layer of wet-bulb gauze to pass through naturally, avoiding gaps and preventing the gauze from piling up and being compressed inside the hole, thus maintaining a uniform evaporation surface. During installation, the wet-bulb temperature sensor is placed as close as possible to the top of the hollow sleeve 16 to ensure the sealing of the sealed container 4 and that no excess gauze is exposed for evaporation except for the wet-bulb gauze covering the temperature sensor surface, thus limiting the effective evaporation area of ​​the wet-bulb gauze. In addition, a 4mm thick insulating cotton is wrapped around the bottle opening to reduce heat exchange between the exposed part of the bottle opening and the environment during the experiment.

[0093] Subsequently, copper tubes were placed inside the sealed container, spiraling along the inner wall of the water tank. The inlets of the copper tubes were connected to a circulation pump in the buffer tank, which introduced water from the buffer tank into the copper tubes. As the water flowed within the tubes, it exchanged heat with the air inside the sealed container before returning to the buffer tank through the outlet. Additionally, a water inlet trough was installed at the bottom of the sealed container, with a 1cm gap between the trough and the sealed container to ensure that the wet-bulb gauze could properly guide water to the temperature sensor. Copper tubes were also placed inside the water inlet trough in the same manner, with cooling water pumped into the inlets by the circulation pump in the buffer tank, exchanging heat with the water in the water inlet trough. After this, calibrated PT100 temperature sensors were installed in the sealed container, the water inlet trough, and the experimental environment to measure the temperature of the microenvironment, the water tank, and the environment. The signals from these sensors were synchronously acquired using an Agilent 34980A multifunction data acquisition system, and these values ​​were used as the real-time basis for the circulation pump start / stop control logic. Data was also recorded via a personal computer.

[0094] During the experimental preparation phase, the ambient temperature was used as a baseline. Pure water at the same temperature as the ambient was added to the water inlet tank, while the water temperature in the buffer tank was maintained at approximately 5°C. Simultaneously, an axial flow fan continuously drew ambient air into the sealed device. At this point, the device was in an open state to ensure complete replacement of the internal gas with ambient air. The bottle opening was then immediately sealed to prevent further exchange between the gas inside the container and the outside environment.

[0095] Figure 3 and Figure 4 Experimental data shows that in the traditional wet-bulb method, there is a heat balance transfer between the latent heat of vaporization and the sensible heat of the effective air film between the dry-bulb and wet-bulb temperatures, resulting in a relatively small decrease in wet-bulb temperature, which does not conform to Dalton's law of partial pressures and the theory of enthalpy-humidity calculation for moist air. However, in the relative humidity measurement of a closed container, the dry-bulb and wet-bulb temperatures eventually tend to be equal, which fully conforms to Dalton's law of partial pressures and the theory of enthalpy-humidity calculation for moist air. That is, when the dry-bulb and wet-bulb temperatures are equal, the air inside the closed container reaches a saturated state, and this temperature is the accurate wet-bulb temperature. Using this wet-bulb temperature, the initial relative humidity of the air can be calculated using the calculation formula in this invention.

[0096] For the parts of this invention not described in detail, please refer to the prior art or the art known to those skilled in the art. This embodiment does not limit these aspects and will not describe them in detail here.

[0097] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. An air relative humidity measurement and calibration device, characterized in that, The device employs Dalton's law of partial pressures, the theory of enthalpy and humidity calculation of moist air, and an improved principle for measuring wet and dry bulb temperatures. By using a sealed container to prevent water vapor from freely diffusing outside the effective air film, the device causes the moist air within the effective air film of the wet-bulb sensor to transition to a saturated air state, eliminating the unsaturated state error of the effective air film in the traditional wet-bulb method. Simultaneously, a cooling device is added to avoid the inaccuracy of wet-bulb measurement caused by the thermal transfer limit temperature difference between the dry and wet bulb temperatures in the traditional wet-bulb method. This achieves the unification of air humidity measurement with Dalton's law of partial pressures, the theory of enthalpy and humidity calculation of moist air, and related thermodynamic theories, providing a benchmark for measuring relative humidity.

2. The air relative humidity measurement and calibration device according to claim 1, characterized in that, The device includes: The sealed container (4) is configured as a sealed space to restrict the free diffusion of water vapor, so that the humid air in the effective gas film of the wet bulb sensor accumulates to a thermodynamic saturation state. A wet-bulb temperature sensor (1) is installed inside the sealed container (4) to measure the temperature after the water evaporates and absorbs heat, causing the temperature to drop. The dry-bulb temperature sensor (2) is placed side by side and at the same height as the wet-bulb temperature sensor (1) inside the sealed container (4) to reflect the thermodynamic intrinsic temperature of the air. The temperature control system ensures that the humid air inside the effective air film forms a saturated state that conforms to Dalton's law of partial pressure and the enthalpy-humidity calculation theory of humid air.

3. The air relative humidity measurement and calibration device according to claim 2, characterized in that, The temperature control system includes a closed container microenvironment temperature control system and a wet bulb water supply temperature control system. The closed container microenvironment temperature control system is configured to control the temperature of the internal environment of the closed container (4); the wet bulb water supply temperature control system is configured to control the water supply temperature of the wet bulb temperature sensor (1).

4. The air relative humidity measurement and calibration device according to claim 3, characterized in that, The closed container microenvironment temperature control system includes insulation cotton (5), closed container microenvironment cooling coil (8), data acquisition controller (12), and buffer water tank (7); the insulation cotton (5) surrounds the outer periphery of the closed container (4), the closed container microenvironment cooling coil (8) is wrapped inside the closed container (4) and connected to the buffer water tank (7), and can control the temperature of the closed container (4) by controlling the flow of cooling water in the buffer water tank (7) in the closed container microenvironment cooling coil (8) under the action of the data acquisition controller (12).

5. The air relative humidity measurement and calibration device according to claim 4, characterized in that, The insulation cotton (5) and the microenvironment cooling coil (8) of the sealed container are used to maintain a constant air temperature inside the sealed container and play a role in heat insulation.

6. The air relative humidity measurement and calibration device according to claim 4, characterized in that, The inner surface of the insulation cotton (5) is provided with an ambient temperature sensor (3), which, together with the ambient air temperature sensor (19) and the dry bulb temperature sensor (2) inside the sealed container, determines in real time the degree of influence of the external ambient temperature on the sealed container.

7. The air relative humidity measurement and calibration device according to claim 3, characterized in that, The wet bulb water supply temperature control system includes a water inlet tank (6), a water inlet tank cooling coil (9), a data acquisition controller (12), and a buffer tank (7). The water inlet tank (6) and the water inlet tank cooling coil (9) are connected, and the water inlet tank cooling coil (9) is connected to the buffer tank (7). Under the action of the data acquisition controller (12), the system can control the temperature of the wet bulb water supply in the water inlet tank (6) by controlling the flow of cooling water in the buffer tank (7) within the water inlet tank cooling coil (9).

8. The air relative humidity measurement and calibration device according to claim 6, characterized in that, The wet-bulb temperature sensor (1), the dry-bulb temperature sensor (2), the ambient temperature sensor (3), the buffer water tank temperature sensor (17), the water inlet tank temperature sensor (18), and the ambient air sensor (19) are all connected to the data acquisition controller (12), and then transmit the data to the host computer. The host computer uses the measurement data of the wet-bulb temperature sensor (1), the dry-bulb temperature sensor (2), the ambient temperature sensor (3), the buffer water tank temperature sensor (17), the water inlet tank temperature sensor (18), and the ambient air sensor (19) to stabilize and regulate the air inside the sealed container. Finally, the host computer calculates the initial relative humidity of the air based on the data of the wet-bulb temperature sensor (1) and the dry-bulb temperature sensor (2).

9. The air relative humidity measurement and calibration device according to claim 2, characterized in that, The diameter of the sealed container (4) is determined as follows: Based on the theory of molecular motion diffusion and energy conservation, the volume of sensors of different shapes and sizes and the volume of wet-bulb gauze were calculated to obtain the volume of the sealed container. Then, according to the theory of isotropy, the installation positions of the wet-bulb temperature sensor (1) and the dry-bulb temperature sensor (2) were determined.

10. The air relative humidity measurement and calibration device according to claim 2, characterized in that, The wet-bulb temperature sensor (1) includes a wet-bulb temperature sensor (1) and a weather wet-bulb gauze (11). The weather wet-bulb gauze (11) covers the temperature sensor head in a single layer and extends downward into the water inlet to contact and connect with water, so as to continuously supply water to the wet bulb. A hollow sleeve (16) is arranged between the lower part of the wet-bulb sensor (1) and the center hole at the bottom of the sealed container to wrap the weather wet-bulb gauze (11), ensuring that only the water content of the weather wet-bulb gauze (11) wrapping the wet-bulb temperature sensor (1) evaporates into the sealed container, preventing excessive evaporation from causing the wet-bulb temperature to be too high.

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