Small phase change thermostatic heating control device, method and gas detection apparatus based on pressure control

Abstract

The application relates to a small-sized phase-change constant-temperature heating control device, a method and a gas detection equipment based on pressure control, which comprise an optoacoustic cell, a temperature sensor, a heater and a central control module; the central control module is connected with the temperature sensor and the heater respectively; the optoacoustic cell comprises a hollow cavity structure and an internal space; the hollow cavity structure is arranged around the internal space of the optoacoustic cell and is in contact with the outer wall of the internal space of the optoacoustic cell; the hollow cavity structure is filled with liquid phase-change material; the temperature sensor is arranged on the outer wall of the optoacoustic cell; and the central control module is used for constant-temperature control of the optoacoustic cell. The device suppresses temperature fluctuation in the optoacoustic cell through the phase-change material in the hollow cavity structure, meanwhile, temperature data is transmitted to the central control module, the central control module realizes temperature control in combination with the heater, and the precision and stability of temperature control are improved.

Description

Technical Field

[0001] This application relates to the field of temperature control technology, and in particular to a small-scale phase change constant temperature heating control device, method and gas detection equipment based on pressure control. Background Technology

[0002] With the increasing demands for transformer safety and reliability in power systems, accurate and efficient detection of dissolved gases in transformer oil has become a crucial aspect of ensuring the healthy operation of power equipment. Photoacoustic spectroscopy gas detection technology, with its high sensitivity and rapid response, demonstrates significant advantages in transformer condition monitoring, effectively identifying potential faults and assessing the aging trends of insulation systems. However, the detection performance of photoacoustic spectroscopy gas detection technology is highly susceptible to environmental factors. Temperature changes can alter the viscosity coefficient, thermal conductivity, and resonant frequency within the photoacoustic cell, causing broadening of gas absorption lines and signal amplitude drift, significantly increasing the measurement error of gas concentration.

[0003] Therefore, how to accurately control the temperature inside the photoacoustic cell and maintain a stable environment has become an urgent problem to be solved. Summary of the Invention

[0004] Therefore, it is necessary to provide a small-scale phase change constant temperature heating control device, method, and gas detection equipment based on pressure control to address the above-mentioned technical problems.

[0005] In a first aspect, this application provides a small-scale phase change isothermal heating control device based on pressure control, comprising:

[0006] The photoacoustic cell comprises a temperature sensor, a heater, and a central control module. The central control module is connected to both the temperature sensor and the heater. The photoacoustic cell includes a hollow cavity structure and an internal space. The hollow cavity structure is arranged around the internal space of the photoacoustic cell and is in contact with the outer wall of the internal space of the photoacoustic cell. The hollow cavity structure is filled with a liquid phase change material. The temperature sensor is located on the outer wall of the photoacoustic cell.

[0007] The central control module is used for constant temperature control of the photoacoustic cell.

[0008] In one embodiment, the pressure-controlled miniature phase change isothermal heating control device further includes:

[0009] Pressure sensor and pressure control module; central control module is connected to both pressure sensor and pressure control module; pressure sensor is connected to pressure control module.

[0010] The central control module is used for constant pressure control of the hollow cavity.

[0011] In one embodiment, the pressure control module includes an air compressor, a controllable valve, a piston, and a pipeline structure; the air compressor is disposed at a first end of the pipeline structure, a second end of the pipeline structure is connected to one end of the controllable valve, and the other end of the controllable valve is connected to an external air pipeline; a third end of the pipeline structure is connected to a hollow cavity structure via a piston; and a pressure sensor is disposed on the inner wall of the pipeline structure.

[0012] The central control module is used to start the air compressor and close the controllable valve when it is determined that pressurization control of the hollow cavity is needed, so that the piston moves to one side of the hollow cavity structure to increase the pressure of the gas in the hollow cavity structure.

[0013] The central control module is also used to shut down the air compressor and open the controllable valve when it is determined that pressure reduction control of the hollow cavity is required, so that the piston moves to the side of the pipe structure to reduce the pressure of the gas in the hollow cavity structure.

[0014] In one embodiment, the hollow cavity structure includes a first cavity structure, a second cavity structure, and a third cavity structure; the first cavity structure, the second cavity structure, and the third cavity structure are connected in sequence; the first cavity structure is arranged around the photoacoustic cell and is in contact with the outer wall of the photoacoustic cell; the first cavity structure is filled with a liquid phase change material; the second cavity structure is filled with a gaseous phase change material; and the third cavity structure is filled with helium.

[0015] In one embodiment, the second cavity structure includes interconnected cavity tubes and multiple heat dissipation holes, with the multiple heat dissipation holes distributed at different locations on the cavity tubes.

[0016] In one embodiment, the liquid phase change material and the gaseous phase change material are electronic fluorinated liquids.

[0017] Secondly, this application also provides a small-scale phase change isothermal control method based on pressure control, comprising:

[0018] Acquire the temperature signal collected by the temperature sensor;

[0019] Based on the temperature signal and the preset target temperature, determine whether it is necessary to control the temperature of the hollow cavity. If it is determined that the hollow cavity needs to be heated, control the heater to heat the photoacoustic cell.

[0020] In one embodiment, the small-scale phase change isothermal control method further includes:

[0021] The pressure signal collected by the pressure sensor is acquired, and the target pressure is determined based on the vapor pressure curve of the phase change material and the target temperature.

[0022] Based on the pressure signal and the preset target pressure, determine whether it is necessary to perform pressurization or depressurization control on the hollow cavity. If it is determined that pressurization or depressurization control is necessary, control the pressure control module to perform constant pressure control on the hollow cavity.

[0023] In one embodiment, when it is determined that pressurization or depressurization control of the hollow cavity is required, the pressure control module is controlled to maintain constant pressure in the hollow cavity, including:

[0024] When it is determined that pressurization control of the hollow cavity is required, the air compressor is started and the controllable valve is closed, causing the piston to move towards one side of the hollow cavity structure, thereby increasing the pressure of the gas in the hollow cavity structure.

[0025] When it is determined that pressure reduction control of the hollow cavity is required, the air compressor is turned off and the controllable valve is opened, causing the piston to move towards the side of the pipe structure, thereby reducing the pressure of the gas in the hollow cavity structure.

[0026] Thirdly, this application also provides a gas detection device, including the aforementioned pressure-controlled small phase change constant temperature heating control device.

[0027] The aforementioned pressure-controlled small-scale phase change isothermal heating control device, method, and gas detection equipment includes a photoacoustic cell, a temperature sensor, a heater, and a central control module. The central control module is connected to both the temperature sensor and the heater. The photoacoustic cell includes a hollow cavity structure and an internal space. The hollow cavity structure is arranged around the internal space of the photoacoustic cell and contacts the outer wall of the internal space of the photoacoustic cell. The hollow cavity structure is filled with a liquid phase change material. The temperature sensor is located on the outer wall of the photoacoustic cell. The central control module is used for isothermal control of the hollow cavity. The aforementioned device suppresses temperature fluctuations within the photoacoustic cell using phase change material (PCM) within a hollow cavity structure. Simultaneously, temperature sensors collect real-time temperature data, transmitting it to a central control module. This central control module, in conjunction with a heater, achieves temperature control, improving its accuracy and stability. Furthermore, the PCM undergoes a phase transition based on its temperature relationship with the environment, generating a thermal effect. Specifically, the liquid PCM transforms into a gaseous state under the heater's influence. Due to its lower density, it rises. When it reaches a point below the PCM temperature (the preset temperature), it transforms from a gaseous state back into a liquid state, releasing heat. This process uniformly transfers the heat generated by the heater to the hollow cavity under constant temperature (PCM temperature). If the temperature throughout the hollow cavity reaches the PCM temperature, the gaseous PCM will exchange heat with the external environment at the heat exchange fins, transforming into a liquid state and flowing back into the hollow cavity due to its higher density. This characteristic reduces the heater's start-up and shutdown frequency and power consumption. Additionally, the hollow cavity structure filled with PCM has a small volume, thus meeting the integration requirements of the photoacoustic cell. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is an application environment diagram of the small phase change constant temperature heating control device in the embodiments of this application;

[0030] Figure 2 This is one of the structural block diagrams of the small phase change constant temperature heating control device in the embodiments of this application;

[0031] Figure 3 This is the second structural block diagram of the small phase change constant temperature heating control device in the embodiments of this application;

[0032] Figure 4 This is the third structural block diagram of the small phase change constant temperature heating control device in the embodiments of this application;

[0033] Figure 5 This is a structural diagram of the small phase change constant temperature heating control device in the embodiments of this application;

[0034] Figure 6 This is one of the flowcharts of a small-scale phase change isothermal heating control method in the embodiments of this application;

[0035] Figure 7 This is the second schematic flowchart of the small phase change isothermal heating control method in the embodiments of this application;

[0036] Figure 8 This is the third flowchart illustrating the small-scale phase change isothermal heating control method in the embodiments of this application;

[0037] Figure 9 This is the fourth flowchart illustrating the small-scale phase change isothermal heating control method in the embodiments of this application. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0039] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0040] With the increasing demands for transformer safety and reliability in power systems, accurate and efficient detection of dissolved gases in transformer oil has become a crucial aspect of ensuring the healthy operation of power equipment. Photoacoustic spectroscopy gas detection technology, with its high sensitivity and rapid response, demonstrates significant advantages in transformer condition monitoring, effectively identifying potential faults and assessing the aging trends of insulation systems. However, the detection performance of photoacoustic spectroscopy gas detection technology is highly susceptible to environmental factors. Temperature changes can alter the viscosity coefficient, thermal conductivity, and resonant frequency within the photoacoustic cell, causing broadening of gas absorption lines and signal amplitude drift, significantly increasing the measurement error of gas concentration.

[0041] Therefore, how to accurately control the temperature inside the photoacoustic cell and maintain a stable environment has become an urgent problem to be solved.

[0042] In view of the above-mentioned technical problems, this application provides a small phase change constant temperature heating control device, method and gas detection device. The following embodiments will specifically describe the small phase change constant temperature heating control device, method and gas detection device.

[0043] In one exemplary embodiment, such as Figure 1 As shown, a small-scale phase change isothermal heating control device based on pressure control is provided. This device includes a photoacoustic cell, a temperature sensor, a heater, and a central control module. The central control module is connected to both the temperature sensor and the heater. The photoacoustic cell includes a hollow cavity structure and an internal space. The hollow cavity structure surrounds the internal space of the photoacoustic cell and contacts the outer wall of the internal space. The hollow cavity structure is filled with a liquid phase change material. The temperature sensor is located on the outer wall of the photoacoustic cell.

[0044] The central control module is used to maintain the constant temperature of the photoacoustic cell.

[0045] The working principle of the pressure-controlled small phase change thermostatic heating control device described in this application embodiment includes: during transformer fault detection, the gas to be tested is first separated from the insulating oil in the transformer by an oil-gas separation device, and then injected into the internal space of the photoacoustic cell. The internal space of the photoacoustic cell is surrounded by an H-shaped hollow cavity structure, and the hollow cavity structure is filled with liquid phase change material, such as electronic fluorinated liquid, hydrocarbons, or hydrofluorocarbons. Simultaneously, multiple temperature sensors are installed on the outer wall of the photoacoustic cell (left outer wall, upper left side of the H-shape, and middle of the H-shape) to collect the temperature data of the photoacoustic cell in real time and transmit the temperature to the central control module. After receiving the real-time temperature, the central control module (such as an electronic control unit) compares the real-time temperature with the target temperature. If the real-time temperature is lower than the target temperature, the central control device generates a heating command and sends the heating command to the heater, which is located directly below the photoacoustic cell and separated from it by a hollow cavity. During the heating process, the heater uses a constant temperature control method (T+X) based on the target temperature T. The temperature difference X allows the heater to transfer heat to the phase change material (PCT), and X can be adjusted according to the ambient temperature t and the target temperature T. Heat is transferred to the hollow cavity, where the liquid PCT absorbs heat and transforms into a gaseous state. At a temperature lower than the target temperature T, the gaseous PCT transforms back into a liquid state, releasing heat. This phase change cycle—from liquid to gas, absorbing heat, and then back to liquid, releasing heat—maintains the temperature inside the hollow cavity at the target temperature T. Since the gas detection core area of ​​the photoacoustic cell, i.e., the internal space, belongs to the same metal structure as the hollow cavity, the high thermal conductivity of the metal structure allows the temperature inside the hollow cavity to rapidly diffuse throughout the entire photoacoustic cell structure, including the internal space, via heat conduction. The central control module's target for constant temperature control is the entire photoacoustic cell. The hollow cavity, as the core carrier of phase change temperature control, directly represents the temperature state of the photoacoustic cell. Therefore, the central control module can maintain the temperature of the hollow cavity at the target temperature T, thereby achieving constant temperature control of the photoacoustic cell.

[0046] In one exemplary embodiment, such as Figure 2 As shown, Figure 1 The small phase change constant temperature heating control device based on pressure control shown also includes: a pressure sensor and a pressure control module; a central control module is connected to both the pressure sensor and the pressure control module; the pressure sensor is connected to the pressure control module.

[0047] The central control module is used to maintain constant pressure in the hollow cavity.

[0048] The working principle of the small phase change constant temperature heating control device based on pressure control described in this application embodiment includes: a pressure control module and a pressure sensor. The pressure control module includes an air compressor, a controllable valve, a piston, and a pipeline structure. The pressure sensor is installed in the pipeline structure of the pressure control module to collect the pressure in the pipeline in real time and transmit the collected pressure data to the central control module. After receiving the pressure data, the central processing module sends a pressurization command or a depressurization command to the pressure control module according to the pressure data so as to perform constant pressure control on the hollow cavity.

[0049] In one exemplary embodiment, such as Figure 3 As shown, Figure 2 The pressure control module includes an air compressor, a controllable valve, a piston, and a piping structure. The air compressor is located at the first end of the piping structure, the second end of the piping structure is connected to one end of the controllable valve, and the other end of the controllable valve is connected to an external air duct. The third end of the piping structure is connected to a hollow cavity structure via a piston. A pressure sensor is located on the inner wall of the piping structure. The piping structure is filled with air.

[0050] The central control module is used to start the air compressor and close the controllable valve when it is determined that pressurization control of the hollow cavity is needed, so that the piston moves to one side of the hollow cavity structure to increase the pressure of the gas in the hollow cavity structure.

[0051] The central control module is also used to shut down the air compressor and open the controllable valve when it is determined that pressure reduction control of the hollow cavity is required, so that the piston moves to the side of the pipe structure to reduce the pressure of the gas in the hollow cavity structure.

[0052] The working principle of the pressure-controlled small phase change constant temperature heating control device described in this application embodiment includes: a pressure sensor collects pressure data p in the pipeline structure in real time and transmits the pressure data p to the central processing module. After receiving the pressure data p, the central processing module starts to calculate the target pressure data P, that is, the central processing module calculates the target pressure data P based on the saturated pressure-temperature relationship and the preset temperature data T. After obtaining the target pressure data P, the central processing module compares the target pressure data P with the pressure data p. If the pressure data p collected by the pressure sensor is less than the target pressure data P, the central controller sends a pressurization control command to the pressure control module to pressurize the gas in the hollow cavity structure. First, the air compressor is started (if the air compressor was previously shut down), and the controllable valve connecting the hollow cavity structure to the outside is closed, making the hollow cavity a closed space. Then, the control motor drives the piston to move at a constant speed to one side of the hollow cavity, increasing the internal pressure by compressing the gas volume in the cavity until the real-time pressure stabilizes and approaches the target pressure P. If the pressure data p collected by the pressure sensor is greater than the target pressure data P, the central controller sends a depressurization control command to the pressure control module to depressurize the gas in the hollow cavity structure. First, the air compressor is shut down (if the air compressor was previously running), and the controllable valve connecting the hollow cavity structure to the outside is opened. Then, the control motor drives the piston to move at a constant speed to one side of the pipe structure, reducing the pressure of the gas in the hollow cavity structure until the real-time pressure stabilizes and approaches the target pressure P.

[0053] In one exemplary embodiment, such as Figure 4 As shown, Figure 1 The hollow cavity structure includes a first cavity structure, a second cavity structure, and a third cavity structure; the first cavity structure, the second cavity structure, and the third cavity structure are connected in sequence; the first cavity structure is arranged around the photoacoustic cell and is in contact with the outer wall of the photoacoustic cell; the first cavity structure is filled with liquid phase change material; the second cavity structure is filled with gaseous phase change material; and the third cavity structure is filled with helium.

[0054] The working principle of the pressure-controlled small phase change isothermal heating control device described in this application embodiment includes: In the pressure-controlled small phase change isothermal heating control device, the hollow structure is composed of a first cavity structure, a second cavity structure, and a third cavity structure connected in sequence. The first cavity structure surrounds the internal space of the photoacoustic cell in an H-shape and is filled with a liquid phase change material (such as electronic fluorinated liquid, hydrocarbons, or hydrofluorocarbons). The second hollow cavity structure is located above the first cavity structure and is filled with a gaseous phase change material (belonging to the same type of phase change material as the liquid phase change material, such as electronic fluorinated liquid, hydrocarbons, or hydrofluorocarbons). The second cavity structure also includes interconnected cavity tubes and multiple heat dissipation holes (such as heat dissipation fins), with the multiple heat dissipation holes distributed at different positions on the cavity tubes. The gaseous phase change material uses the multiple heat dissipation holes (such as heat dissipation fins) to exchange heat with the outside air to achieve condensation. The third cavity structure is located above the second cavity structure and is filled with a stable gas used to isolate the phase change material from the outside air, such as helium, argon, or neon, or other stable gases. Figure 5 As shown, the third cavity structure is connected to the second cavity structure at one end and to a movable piston at the other end. The pressure inside the hollow cavity is adjusted by the movement of the piston. Since the gas inside the pipe is interconnected, the pressure in the three parts of the hollow cavity structure can be considered to be the same. Therefore, the pressure sensor installed in the pipe can also be directly used to detect the pressure inside the hollow cavity.

[0055] The aforementioned device suppresses temperature fluctuations within the photoacoustic cell using phase change material (PCM) within a hollow cavity structure. Simultaneously, temperature sensors collect real-time temperature data, transmitting it to a central control module. This central control module, in conjunction with a heater, achieves temperature control, improving its accuracy and stability. Furthermore, the PCM undergoes a phase transition based on its temperature relationship with the environment, generating a thermal effect. Specifically, the liquid PCM transforms into a gaseous state under the heater's influence. Due to its lower density, it rises. When it reaches a point below the PCM temperature (the preset temperature), it transforms from a gaseous state back into a liquid state, releasing heat. This process uniformly transfers the heat generated by the heater to the hollow cavity under constant temperature (PCM temperature). If the temperature throughout the hollow cavity reaches the PCM temperature, the gaseous PCM will exchange heat with the external environment at the heat exchange fins, transforming into a liquid state and flowing back into the hollow cavity due to its higher density. This characteristic reduces the heater's start-up and shutdown frequency and power consumption. Additionally, the hollow cavity structure filled with PCM has a small volume, thus meeting the integration requirements of the photoacoustic cell.

[0056] In one exemplary embodiment, based on the pressure-controlled small phase change isothermal heating control device described in any of the foregoing embodiments, a pressure-controlled small phase change isothermal control method is also provided, such as... Figure 6 As shown, it includes:

[0057] S101, acquire the temperature signal collected by the temperature sensor.

[0058] In this embodiment, the central control module uses multiple temperature sensors located on the outer wall of the photoacoustic pool (left outer wall, upper left side of the H-shape, and middle of the H-shape) to collect the temperature of the hollow cavity, and determines whether the hollow cavity is in a constant temperature state based on the collected temperature signals.

[0059] S102 determines whether the hollow cavity needs to be heated based on the temperature signal and the preset target temperature, and controls the heater to heat the hollow cavity if it is determined that the hollow cavity needs to be heated.

[0060] In this embodiment, after receiving the temperature signal t from the temperature sensor, the central control module compares the temperature signal t with the preset target temperature signal T to determine whether the hollow cavity needs to be heated. If the real-time temperature t is lower than the target temperature T, the central control device generates a heating command and sends it to the heater. The heater uses a constant temperature T+X control method based on the target temperature T (the existence of temperature difference X allows the heater to transfer heat to the phase change material; X can be adjusted according to the ambient temperature t1 and the target temperature T; for example, if the real-time temperature is too low, X can be appropriately increased to accelerate heat transfer efficiency). Heat is transferred to the hollow cavity, where the liquid phase change material absorbs heat and changes phase to gas. The gaseous phase change material changes phase to liquid at a temperature lower than the target temperature T (such as the inner wall of the hollow cavity or other low-temperature areas), releasing heat, thereby maintaining the overall temperature of the hollow cavity stable near the target value. For example, if the target temperature T is set to 50°C and the ambient temperature is 25°C, X can be set to 5°C, and the heater operates at a constant temperature of 55°C. When the real-time temperature of the hollow cavity is t=40℃, which is lower than 50℃, the central control module sends a heating command. The heater starts and transfers heat to the cavity. The liquid phase change material absorbs heat and turns into a gaseous state at a constant temperature of 50℃. The gaseous phase change material turns back into a liquid state when it encounters cold at a lower temperature in the cavity (such as the inner wall near the sensor), releasing heat and causing the cavity temperature to gradually rise to 50℃.

[0061] In an exemplary embodiment, the above-described pressure-controlled small-scale phase change isothermal control method, such as... Figure 7 As shown, it also includes:

[0062] S201, acquire the pressure signal collected by the pressure sensor, and determine the target pressure based on the vapor pressure curve of the phase change material and the target temperature.

[0063] In this embodiment of the application, the central controller uses a pressure sensor to acquire a pressure signal, and at the same time calculates the target pressure data P based on the vapor pressure curve of the phase change material and the preset temperature data T to determine the value of the target pressure.

[0064] S202 determines whether pressure boosting or pressure reduction control is needed for the hollow cavity based on the pressure signal and the preset target pressure, and controls the pressure control module to perform constant pressure control on the hollow cavity if pressure boosting or pressure reduction control is needed.

[0065] In this embodiment, after receiving the pressure data, the central processing module sends a pressurization command or a depressurization command to the pressure control module to control the hollow cavity under constant pressure.

[0066] In an exemplary embodiment, the phrase "when it is determined that pressurization or depressurization control of the hollow cavity is required, the pressure control module is controlled to perform constant pressure control on the hollow cavity" in S202 above, such as... Figure 8 As shown, it includes:

[0067] S301, when it is determined that pressurization control of the hollow cavity is required, the air compressor is started and the controllable valve is closed, so that the piston moves to one side of the hollow cavity structure, increasing the pressure of the gas in the hollow cavity structure.

[0068] In this embodiment, after obtaining the target pressure and the real-time pressure signal, the central processing unit compares the target pressure with the real-time pressure signal. If the pressure data p collected by the pressure sensor is less than the target pressure data P, the central controller sends a pressurization control command to the pressure control module to pressurize the gas in the hollow cavity structure. First, the air compressor is started (if the air compressor was previously stopped), and at the same time, the controllable valve connecting the hollow cavity structure to the outside is closed, so that the hollow cavity forms a closed space. Then, the control motor drives the piston to move at a constant speed to one side of the hollow cavity, thereby increasing the internal pressure by compressing the gas volume in the cavity until the real-time pressure stabilizes and approaches the target pressure P.

[0069] S302, when it is determined that pressure reduction control of the hollow cavity is required, the air compressor is turned off and the controllable valve is opened, so that the piston moves to the side of the pipe structure to reduce the pressure of the gas in the hollow cavity structure.

[0070] In this embodiment, after obtaining the target pressure and the real-time pressure signal, the central processing unit compares the target pressure and the real-time pressure signal. If the pressure data p collected by the pressure sensor is greater than the target pressure data P, the central controller sends a pressure reduction control command to the pressure control module to reduce the pressure of the gas in the hollow cavity structure. First, the air compressor is turned off (if the air compressor was working before), and at the same time, the controllable valve connecting the hollow cavity structure to the outside is opened. Then, the control motor drives the piston to move at a constant speed to one side of the pipe structure to reduce the pressure of the gas in the hollow cavity structure until the real-time pressure stabilizes and approaches the target pressure P.

[0071] In summary, based on all the above embodiments, a small-scale phase change isothermal heating control method based on pressure control is also provided, such as... Figure 9 As shown, the method includes:

[0072] S401 executes S402-S403 to perform constant temperature control on the photoacoustic cell; S404-S407 executes S404-S407 to perform constant pressure control on the hollow cavity.

[0073] S402, acquire the temperature signal collected by the temperature sensor;

[0074] S403 determines whether the hollow cavity needs to be heated based on the temperature signal and the preset target temperature, and controls the heater to heat the photoacoustic cell if it is determined that the photoacoustic cell needs to be heated.

[0075] S404: Acquire the pressure signal collected by the pressure sensor, and determine the target pressure based on the vapor pressure curve of the phase change material and the target temperature;

[0076] S405: Determine whether to perform pressurization or depressurization control on the hollow cavity based on the pressure signal and the preset target pressure; execute S406 to perform pressurization control; execute S407 to perform depressurization control.

[0077] S406, when it is determined that pressurization control of the hollow cavity is required, the air compressor is started and the controllable valve is closed, so that the piston moves to one side of the hollow cavity structure, increasing the pressure of the gas in the hollow cavity structure;

[0078] S407 When it is determined that pressure reduction control of the hollow cavity is required, the air compressor is turned off and the controllable valve is opened, causing the piston to move towards the side of the pipe structure, thereby reducing the pressure of the gas in the hollow cavity structure.

[0079] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.

[0080] Based on the same inventive concept, this application also provides a gas detection device for implementing the aforementioned pressure-controlled small phase change isothermal heating control device. This gas detection device includes the aforementioned pressure-controlled small phase change isothermal heating control device; therefore, specific limitations on the gas detection device can be found in the above-described limitations on the pressure-controlled small phase change isothermal heating control device, and will not be repeated here.

[0081] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0082] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0083] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A small-scale phase change isothermal control device based on pressure control, characterized in that, The device includes: a photoacoustic cell, a temperature sensor, a heater, and a central control module; the central control module is connected to the temperature sensor and the heater respectively; the photoacoustic cell includes a hollow cavity structure and an internal space; the hollow cavity structure is arranged around the internal space of the photoacoustic cell, and the hollow cavity structure is in contact with the outer wall of the internal space of the photoacoustic cell; the hollow cavity structure is filled with a liquid phase change material; the temperature sensor is disposed on the outer wall of the photoacoustic cell; The central control module is used to maintain a constant temperature for the photoacoustic cell.

2. The apparatus according to claim 1, characterized in that, The device further includes: a pressure sensor and a pressure control module; the central control module is connected to both the pressure sensor and the pressure control module; the pressure sensor is connected to the pressure control module. The central control module is used to maintain constant pressure in the hollow cavity.

3. The apparatus according to claim 2, characterized in that, The pressure control module includes an air compressor, a controllable valve, a piston, and a pipeline structure; the air compressor is located at the first end of the pipeline structure, the second end of the pipeline structure is connected to one end of the controllable valve, and the other end of the controllable valve is connected to an external air pipeline; the third end of the pipeline structure is connected to the hollow cavity structure via the piston; and the pressure sensor is located on the inner wall of the pipeline structure. The central control module is used to start the air compressor and close the controllable valve when it is determined that pressurization control of the hollow cavity is required, so that the piston moves towards the hollow cavity structure to increase the pressure of the gas in the hollow cavity structure. The central control module is also used to shut down the air compressor and open the controllable valve when it is determined that pressure reduction control of the hollow cavity is required, so that the piston moves toward the side of the pipeline structure to reduce the pressure of the gas in the hollow cavity structure.

4. The apparatus according to any one of claims 1 to 3, characterized in that, The hollow cavity structure includes a first cavity structure, a second cavity structure, and a third cavity structure; the first cavity structure, the second cavity structure, and the third cavity structure are connected in sequence; the first cavity structure is arranged around the photoacoustic cell and is in contact with the outer wall of the photoacoustic cell; the first cavity structure is filled with liquid phase change material; the second cavity structure is filled with gaseous phase change material; and the third cavity structure is filled with helium.

5. The apparatus according to claim 4, characterized in that, The second cavity structure includes interconnected cavity tubes and multiple heat dissipation holes, and the multiple heat dissipation holes are distributed at different positions of the cavity tubes.

6. The apparatus according to claim 4, characterized in that, The liquid phase change material and the gaseous phase change material are electronic fluorinated liquids.

7. A small-scale phase change isothermal control method based on pressure control, characterized in that, The method, applied to the central control module in the pressure-controlled small phase change isothermal control device as described in any one of claims 1-6, comprises: Acquire the temperature signal collected by the temperature sensor; Based on the temperature signal and the preset target temperature, it is determined whether the hollow cavity needs to be heated. If it is determined that the hollow cavity needs to be heated, the heater is controlled to heat the photoacoustic cell.

8. The method according to claim 7, characterized in that, The method further includes: The pressure signal collected by the pressure sensor is acquired, and the target pressure is determined based on the vapor pressure curve of the phase change material and the target temperature. Based on the pressure signal and the target pressure, determine whether it is necessary to perform pressurization or depressurization control on the hollow cavity, and if it is determined that pressurization or depressurization control is necessary, control the pressure control module to perform constant pressure control on the hollow cavity.

9. The method according to claim 8, characterized in that, When it is determined that pressurization or depressurization control of the hollow cavity is required, the pressure control module is controlled to maintain constant pressure in the hollow cavity, including: When it is determined that pressurization control of the hollow cavity is required, the air compressor is started and the controllable valve is closed, causing the piston to move towards one side of the hollow cavity structure, thereby increasing the pressure of the gas in the hollow cavity structure; When it is determined that pressure reduction control of the hollow cavity is required, the air compressor is turned off and the controllable valve is opened, causing the piston to move towards the side of the pipe structure, thereby reducing the pressure of the gas in the hollow cavity structure.

10. A gas detection device, characterized in that, Includes the small phase change thermostatic control device based on pressure control as described in any one of claims 1-6.

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