A gas supplementing device capable of detecting water content

Abstract

The utility model belongs to mechanical engineering field, aims at solving the problem that the air supplement device of large-scale hydropower station hydraulic system cannot monitor the moisture content of inlet air, water seepage causes hidden danger and is difficult to early warning, provides a kind of air supplement device of moisture content detection, including air supplement valve body, the air inlet pipeline of intercommunication, the moisture content of PVA humidity sensing membrane is equipped near the air inlet of air inlet pipeline first section, PVA humidity sensing membrane is fixed between double electrode, the resistance type humidity sensor assembly of double electrode, still contain the signal processing circuit of electric connection with double electrode, and the direct current power supply module of 24V electricity for its supply.The utility model has the beneficial effect that compact integration, easy to embed, high sensitivity, quick response, stable operation, can improve air supplement safety and stability, reduce maintenance cost and failure downtime risk.

Description

Technical Field

[0001] This utility model relates to the field of mechanical engineering technology, and more specifically, to a gas replenishment device capable of detecting moisture content. Background Technology

[0002] In the production and operation of large hydropower stations, the hydraulic system is a key power source to ensure the stable operation of core equipment. It mainly provides power support for key operations such as the opening control of turbine guide vanes and the opening and closing of cylinder valves, which directly affects the power generation efficiency and operational safety of the hydropower station. In order to ensure the stability of hydraulic system pressure, avoid cavitation, and buffer pressure fluctuations, it is necessary to periodically replenish the system with gas at a specific pressure through an air replenishment device, or release gas when the pressure is too high, in order to maintain the system pressure balance. Therefore, the air replenishment device is an indispensable auxiliary equipment for the hydraulic system.

[0003] However, hydraulic oil in hydraulic systems is highly hygroscopic. During long-term operation, moisture in the air can easily seep into the hydraulic oil through the air intake channel of the air replenishment device and system leaks, leading to an increase in the oil's water content. This can cause multiple serious hidden dangers. First, moisture accelerates the oxidative degradation process of the hydraulic oil, generating acidic substances. These acidic substances corrode metal components within the hydraulic system (such as valve cores, valve sleeves, pipe inner walls, oil tanks, and actuator cylinders). Simultaneously, corrosion byproducts such as rust and sludge contaminates the oil, exacerbating wear on moving parts and potentially clogging precision valve ports and filters, leading to system malfunctions. Second, moisture entering the hydraulic oil easily forms emulsions, significantly reducing the oil's viscosity and strength, making it unable to function properly. First, moisture can cause friction between metal components, disrupting system pressure stability and affecting the hydraulic system's precise control over turbine guide vanes and valves. Second, moisture can severely damage the lubrication performance of hydraulic oil, leading to poor lubrication of moving parts such as bearings, pistons, valve cores, and oil pumps, significantly shortening the service life of these critical components and increasing equipment maintenance costs and downtime risks. Third, in high-pressure areas such as oil pump suction ports and throttle valves, water dissolved in the oil can rapidly vaporize into bubbles when pressure drops suddenly. These bubbles collapse instantly under high pressure, generating extremely strong local shock waves and high temperatures, causing cavitation, resulting in pitting and dents on metal surfaces, damaging critical components such as oil pumps and valves, and accompanied by significant noise and vibration, further affecting system stability.

[0004] The existing air replenishment device operates solely based on changes in system air or oil pressure, and its enclosed structure lacks any moisture detection sensors, making it impossible to obtain the real-time moisture content of the gas entering the hydraulic system. Furthermore, the moisture content cannot be directly reflected through conventional parameters such as pressure and flow rate, making it difficult to provide early warnings of potential issues such as excessive oil moisture content and hindering timely intervention measures. This poses a significant risk to the long-term stable operation of the hydraulic system. Utility Model Content

[0005] The present invention aims to provide an air replenishment device that can detect moisture content, in order to solve the problem that the existing air replenishment devices of large hydropower station hydraulic systems cannot monitor the moisture content of the incoming air, which easily leads to moisture infiltration, causing multiple hidden dangers and making it difficult to provide early warning.

[0006] The embodiments of this utility model are implemented as follows: This utility model embodiment provides an air replenishment device capable of detecting moisture content, which includes an air replenishment valve body and an air inlet pipe connected to the air replenishment valve body. It also includes a resistive humidity sensor assembly, which is disposed near the first section of the air inlet of the air intake pipe. The resistive humidity sensor assembly includes a PVA humidity-sensitive film and a dual-electrode structure. The PVA humidity-sensitive film is fixed between the dual-electrode structure, and the surface of the PVA humidity-sensitive film is in full contact with the airflow in the air intake pipe. The signal processing circuit is electrically connected to the dual-electrode structure, and the signal processing circuit includes an operational amplifier module and a comparison module. DC power supply module, the DC power supply module provides 24V DC power to the signal processing circuit; After the PVA moisture-sensitive membrane absorbs moisture, its resistance decreases. The dual-electrode structure captures this change in resistance and outputs an electrical signal to the operational amplifier module. The operational amplifier module amplifies and shapes the electrical signal and outputs a stable voltage signal to the comparison module. The comparison module compares the stable voltage signal with a reference voltage signal corresponding to a preset moisture content threshold. When the stable voltage signal is greater than the reference voltage signal, the comparison module outputs a high level to trigger an alarm.

[0007] When in use, the entire device must first be connected to the power control circuit of the hydraulic system of a large hydropower station: the above-mentioned air replenishment valve body is the core actuator, and its above-mentioned air inlet pipe must be connected to an external air source to ensure that the gas is delivered according to the pressure requirements of the hydraulic system; the above-mentioned resistive humidity sensor assembly must be accurately installed near the first section of the air inlet of the above-mentioned air inlet pipe, and the above-mentioned PVA humidity-sensitive membrane in the assembly must be clamped and fixed between the above-mentioned dual electrode structure, and the surface of the above-mentioned PVA humidity-sensitive membrane must be in full contact with the airflow in the above-mentioned air inlet pipe to ensure that the original moisture content of the gas before entering the above-mentioned air replenishment valve body can be captured in real time; Then the DC power supply module is activated to provide a stable 24V DC power supply to the signal processing circuit. When an external air source delivers gas to the gas replenishment valve body through the air inlet pipe, if the gas contains moisture, the PVA humidity-sensitive membrane will absorb moisture and its resistance will decrease. The dual-electrode structure can capture this resistance change in real time and output an electrical signal, which will be transmitted to the signal processing circuit. After receiving the electrical signal, the signal processing circuit first amplifies and shapes the signal through the operational amplifier module, converting it into a stable voltage signal. Then, the comparison module compares this voltage signal with the reference voltage signal corresponding to the preset moisture content threshold. If the voltage signal does not exceed the threshold (gas moisture content is normal), the device replenishes gas to the hydraulic system normally. If the voltage signal exceeds the threshold (gas moisture content is abnormal), the signal processing circuit outputs a high level to trigger an alarm. At the same time, it can link the PLC control unit of the hydraulic system, or cut off the gas supply solenoid valve of the PLC gas replenishment valve body to stop the gas supply, or start the matching drying equipment to process the gas source, thus preventing high-humidity gas from entering the hydraulic system from the source and ensuring the stable operation of the hydraulic system.

[0008] The air replenishment device disclosed in this embodiment, capable of detecting moisture content, utilizes a resistive humidity sensor assembly comprising a PVA humidity-sensitive membrane and dual electrodes installed in the air inlet pipe of the air replenishment valve body. Combined with the signal processing circuit and the DC power supply module, it can monitor the moisture content of the incoming air in real time. This results in an air replenishment device that is compact and integrated, requires no complex external equipment, is easy to embed into existing systems, has high sensitivity, fast response, stable operation, improves the safety and stability of air replenishment, and reduces maintenance costs and the risk of downtime due to malfunctions.

[0009] Optionally: The air intake pipe is provided with a transparent observation section downstream of the resistive humidity sensor assembly. The transparent observation section contains a moisture-sensitive color-changing silicone, the color of which changes with the humidity of the gas in the air intake pipe.

[0010] With this setup, and by using the aforementioned transparent observation section and moisture-sensitive color-changing silica gel, operators can intuitively determine the moisture content of the intake air without disassembling the equipment. This provides visual assistance for moisture content monitoring, improving maintenance convenience and monitoring reliability.

[0011] Optionally: the operational amplifier module includes a voltage follower U1, and the comparator module includes a comparator U2; The above signal processing circuit also includes a first voltage divider resistor R1, a second voltage divider resistor R2, and a third voltage divider resistor R3; The input terminal of the voltage follower U1 is electrically connected to the output terminal of the dual-electrode structure and one end of the first voltage divider resistor R1, and the other end of the first voltage divider resistor R1 is grounded. The positive input terminal of the comparator U2 is electrically connected to the output terminal of the voltage follower U1. The negative input terminal of the comparator U2 is electrically connected to one end of the second voltage divider resistor R2 and one end of the third voltage divider resistor R3. The other end of the second voltage divider resistor R2 is electrically connected to the output terminal of the DC power supply module. The other end of the third voltage divider resistor R3 is grounded. The resistance values ​​of the first voltage divider resistor R1, the second voltage divider resistor R2, and the third voltage divider resistor R3 are all 5MΩ.

[0012] This setup clearly defines the specific components, resistance values, and connections of the signal processing circuit, ensuring that the circuit can accurately amplify and compare electrical signals, guaranteeing the accuracy and stability of moisture content detection. At the same time, the standardized circuit structure facilitates production assembly and subsequent maintenance.

[0013] Optionally, it also includes a PLC control system, which is equipped with a DI module, and the output of the comparator module is electrically connected to the DI module; When the comparison module outputs a high level, the PLC control system can shut off the gas supply solenoid valve of the aforementioned gas supply valve body, or start the gas drying system that is matched with the aforementioned air intake pipeline.

[0014] This setup, through interface with the PLC control system, enables automatic linkage control under high humidity conditions. It can promptly cut off the gas supply solenoid valve or start the drying system, reducing manual intervention and improving the automation level of the device and safety redundancy in unattended scenarios.

[0015] Optionally, the above dual-electrode structure consists of two vertically arranged metal electrodes, with the PVA humidity-sensitive membrane clamped and fixed between the two metal electrodes.

[0016] This configuration, with the PVA humidity-sensitive membrane clamped and fixed by vertical metal electrodes, ensures full contact between the membrane and the airflow, thereby improving the detection effect and sensitivity of the resistive humidity sensor assembly.

[0017] Optionally, the above-mentioned signal processing circuit is integrated into a modular detection box, which can be detachably installed on the outside of the housing of the above-mentioned air replenishment valve body, or embedded in the housing of the above-mentioned air replenishment valve body.

[0018] This configuration, by integrating the aforementioned signal processing circuit into the modular detection box and adopting a detachable installation method, facilitates the individual inspection, replacement, and subsequent modification of the circuit modules, reduces maintenance costs, and adapts to different installation scenarios, thereby improving the versatility of the device.

[0019] Optionally, the PVA humidity-sensitive film is a polyvinyl alcohol film that has undergone cross-linking modification, the thickness of the PVA humidity-sensitive film is 0.1 mm to 0.5 mm, and the surface of the PVA humidity-sensitive film is provided with micron-sized air pores.

[0020] With this configuration, the PVA moisture-sensitive membrane, which has been cross-linked and modified with micron-sized pores, can improve the moisture absorption response speed and detection sensitivity. The specific thickness design ensures the structural strength and stability of the membrane, further optimizing the moisture content detection effect.

[0021] Optionally: the sensor placement area of ​​the above-mentioned intake pipe is an inwardly recessed annular step structure, the above-mentioned dual electrode structure is fixed to the inner wall of the annular step by bolts, and the outer periphery of the above-mentioned PVA humidity-sensitive film is sealed and abutted against the step surface of the annular step.

[0022] This configuration provides a stable mounting base for the aforementioned resistive humidity sensor assembly, while the bolt fixing and sealing design ensure that the assembly is securely installed without airflow leakage, guaranteeing detection accuracy and the sealing of the aforementioned air intake pipe.

[0023] Optionally, the DC power supply module is integrated into the modular testing box. The side wall of the modular testing box is provided with a snap-fit ​​structure that is compatible with the housing of the air replenishment valve. The modular testing box is detachably connected to the housing of the air replenishment valve through the snap-fit ​​structure.

[0024] This design, with the DC power supply module and the modular testing box connected by a snap-fit ​​mechanism, simplifies the overall structure of the device, facilitates the synchronous installation and disassembly of the DC power supply module and the modular testing box, and improves the ease of assembly and maintenance of the device.

[0025] Optionally: The output of the comparator module is equipped with a standardized terminal block, which is a DB9 type interface. The DB9 type interface is electrically connected to the DI module of the PLC control system or an external alarm device through a shielded cable.

[0026] This setup, with its DB9 standardized terminals and shielded cables, ensures stable signal transmission and interference resistance, facilitating quick connection with PLCs or external alarm devices and improving the reliability and compatibility of the device's signal output.

[0027] In summary, the gas replenishment device for detecting moisture content disclosed in this utility model has the advantages of compact integration, no need for complex external equipment, easy embedding into existing systems, high sensitivity, fast response, stable operation, improved gas replenishment safety and stability, and reduced maintenance costs and downtime risks. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of an air-injection device capable of detecting moisture content in an embodiment of this utility model; Figure 2This is a circuit diagram of a gas replenishment device capable of detecting moisture content, as described in an embodiment of this utility model.

[0030] Icons: 1- Air supply valve body, 2- Air inlet pipe, 3- Resistive humidity sensor assembly, 4- PVA humidity-sensitive film, 5- Dual electrode structure, 6- Signal processing circuit, 7- DC power supply module, 8- Transparent observation section, 9- Voltage follower U1, 10- Comparator U2, 11- First voltage divider resistor R1, 12- Second voltage divider resistor R2, 13- Third voltage divider resistor R3, 14- Modular detection box. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0032] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0033] Example See Figure 1 and Figure 2 This embodiment proposes an air replenishment device capable of detecting moisture content, including an air replenishment valve body 1 and an air inlet pipe 2 connected to the air replenishment valve body 1. It also includes a resistive humidity sensor assembly 3, which is located near the first section of the air inlet of the air inlet pipe 2. The resistive humidity sensor assembly 3 includes a PVA humidity-sensitive film 4 and a dual-electrode structure 5. The PVA humidity-sensitive film 4 is fixed between the dual-electrode structures 5, and the surface of the PVA humidity-sensitive film 4 is in full contact with the airflow in the air inlet pipe 2. Signal processing circuit 6 is electrically connected to dual-electrode structure 5. Signal processing circuit 6 includes an operational amplifier module (not shown in the figure) and a comparison module (not shown in the figure). DC power supply module 7 provides 24V DC power to signal processing circuit 6; After the PVA humidity-sensitive membrane 4 absorbs moisture, its resistance value decreases. The dual-electrode structure 5 captures the change in resistance value and outputs an electrical signal to the operational amplifier module. The operational amplifier module amplifies and shapes the electrical signal and outputs a stable voltage signal to the comparison module. The comparison module compares the stable voltage signal with the reference voltage signal corresponding to the preset moisture content threshold. When the stable voltage signal is greater than the reference voltage signal, the comparison module outputs a high level to trigger an alarm.

[0034] When in use, the entire device must first be connected to the power control circuit of the hydraulic system of a large hydropower station: the air supply valve body 1 is the core actuator, and its air inlet pipe 2 must be connected to an external air source to ensure that the gas is delivered according to the pressure requirements of the hydraulic system; the resistive humidity sensor assembly 3 must be accurately installed near the first air inlet of the air inlet pipe 2, and the PVA humidity-sensitive membrane 4 in the assembly must be clamped and fixed between the dual electrode structure 5, and the surface of the PVA humidity-sensitive membrane 4 must be in full contact with the airflow in the air inlet pipe 2 to ensure that the original moisture content of the gas before entering the air supply valve body 1 can be captured in real time; Then the DC power supply module 7 is activated to provide a stable 24V DC power supply to the signal processing circuit 6. When the external air source delivers gas to the air supply valve body 1 through the air inlet pipe 2, if the gas contains moisture, the PVA humidity-sensitive membrane 4 will absorb moisture and its own resistance value will decrease. The dual electrode structure 5 can capture this resistance change in real time and output an electrical signal, which will be transmitted to the signal processing circuit 6. After receiving the electrical signal, the signal processing circuit 6 first amplifies and shapes the signal through the operational amplifier module, converting it into a stable voltage signal. Then, the comparison module compares this voltage signal with the reference voltage signal corresponding to the preset moisture content threshold. If the voltage signal does not exceed the threshold (gas moisture content is normal), the device replenishes gas to the hydraulic system normally. If the voltage signal exceeds the threshold (gas moisture content is abnormal), the signal processing circuit 6 outputs a high level to trigger an alarm. At the same time, it can link the PLC control unit of the hydraulic system, or cut off the gas supply solenoid valve of the PLC gas replenishment valve body 1 to stop the gas supply, or start the matching drying equipment to process the gas source, thereby preventing high-humidity gas from entering the hydraulic system from the source and ensuring the stable operation of the hydraulic system.

[0035] This embodiment discloses a moisture-content-detecting air replenishment device. By incorporating a resistive humidity sensor assembly 3 containing a PVA moisture-sensitive membrane 4 and dual electrodes in the air inlet pipe 2 of the air replenishment valve body 1, along with a signal processing circuit 6 and a DC power supply module 7, the device can monitor the moisture content of the incoming air in real time. The resistance change of the PVA moisture-sensitive membrane 4 after absorbing moisture is captured by the dual electrodes, amplified by the signal processing circuit 6, and compared with a threshold voltage to determine whether it exceeds the standard. This blocks high-humidity gas at the source, avoiding potential hazards such as metal corrosion and oil deterioration in the hydraulic system. Consequently, this moisture-content-detecting air replenishment device has the beneficial effects of compact integration, no need for complex external equipment, easy embedding into existing systems, high sensitivity, fast response, stable operation, improved air replenishment safety and stability, and reduced maintenance costs and downtime risks.

[0036] See Figure 1 and Figure 2 A transparent observation section 8 is provided downstream of the resistive humidity sensor assembly 3 in the air intake pipe 2. The transparent observation section 8 contains a moisture-sensitive color-changing silicone (not shown in the figure). The color of the moisture-sensitive color-changing silicone changes with the humidity of the gas in the air intake pipe 2. With the help of the transparent observation section 8 and the moisture-sensitive color-changing silicone, operators can intuitively judge the moisture content of the intake air without disassembling the equipment, providing visual assistance for moisture content monitoring and improving maintenance convenience and monitoring reliability.

[0037] The operational amplifier module includes a voltage follower U19, and the comparator module includes a comparator U210. The signal processing circuit 6 also includes a first voltage divider resistor R111, a second voltage divider resistor R212, and a third voltage divider resistor R313. The input terminal of the voltage follower U19 is electrically connected to the output terminal of the dual-electrode structure 5 and one end of the first voltage divider resistor R111, while the other end of the first voltage divider resistor R111 is grounded. The positive input terminal of the comparator U210 is electrically connected to the output terminal of the voltage follower U19, and the negative input terminal of the comparator U210 is electrically connected to the second voltage divider resistor R211. One end of resistor 2 and one end of the third voltage divider resistor R313 are electrically connected. The other end of the second voltage divider resistor R212 is electrically connected to the output terminal of the DC power supply module 7. The other end of the third voltage divider resistor R313 is grounded. The resistance values ​​of the first voltage divider resistor R111, the second voltage divider resistor R212, and the third voltage divider resistor R313 are all 5MΩ. This clarifies the specific component composition, resistance values, and connection relationships of the signal processing circuit 6, ensuring that the circuit can accurately amplify and compare electrical signals, guaranteeing the accuracy and stability of moisture content detection. At the same time, the standardized circuit structure facilitates production assembly and subsequent maintenance.

[0038] See Figure 1 and Figure 2It also includes a PLC control system (not shown in the figure). The PLC control system is equipped with a DI module, and the output of the comparator module is electrically connected to the DI module. When the comparator module outputs a high level, the PLC control system can shut off the gas supply solenoid valve (not shown in the figure) of the gas supply valve body 1, or start the gas drying system (not shown in the figure) matched with the air intake pipeline 2. By interfacing with the PLC control system, automatic linkage control under high humidity conditions can be realized. The gas supply solenoid valve can be shut off in time or the drying system can be started, reducing manual intervention and improving the automation level of the device and the safety redundancy in unattended scenarios.

[0039] The dual-electrode structure 5 consists of two vertically arranged metal electrodes. The PVA humidity-sensitive membrane 4 is clamped and fixed between the two metal electrodes. By clamping and fixing the PVA humidity-sensitive membrane 4 with the vertical metal electrodes, the membrane is ensured to have full contact with the airflow, thereby improving the detection effect and sensitivity of the resistive humidity sensor assembly 3.

[0040] See Figure 1 and Figure 2 The signal processing circuit 6 is integrated into the modular testing box 14. The modular testing box 14 can be detachably installed on the outside of the housing of the air supply valve body 1 or embedded in the housing of the air supply valve body 1. By integrating the signal processing circuit 6 into the modular testing box 14 and adopting a detachable installation method, it is convenient to inspect, replace and modify the circuit module separately, reduce maintenance costs, adapt to different installation scenarios and improve the versatility of the device.

[0041] The PVA humidity-sensitive membrane 4 is a cross-linked modified polyvinyl alcohol film. The thickness of the PVA humidity-sensitive membrane 4 is 0.1mm to 0.5mm, and the surface of the PVA humidity-sensitive membrane 4 is provided with micron-sized air pores. The cross-linked modified PVA humidity-sensitive membrane 4 with micron-sized air pores can improve the moisture absorption response speed and detection sensitivity. The specific thickness design ensures the structural strength and stability of the membrane, further optimizing the moisture content detection effect.

[0042] The sensor placement area of ​​the intake pipe 2 is an inwardly recessed annular step structure (not shown in the figure). The dual electrode structure 5 is fixed to the inner wall of the annular step by bolts. The outer periphery of the PVA humidity-sensitive membrane 4 is sealed and abutted against the step surface of the annular step. The annular step structure provides a stable mounting base for the resistive humidity sensor assembly 3. The bolt fixing and sealing abutment design ensure that the assembly is firmly installed and there is no airflow leakage, thus ensuring the detection accuracy and the sealing of the intake pipe 2.

[0043] See Figure 1 and Figure 2The DC power supply module 7 is integrated into the modular testing box 14. The side wall of the modular testing box 14 is provided with a snap-fit ​​structure (not shown in the figure) that is compatible with the housing of the air supply valve body 1. The modular testing box 14 is detachably connected to the housing of the air supply valve body 1 through the snap-fit ​​structure. The DC power supply module 7 and the modular testing box 14 are designed with snap-fit ​​connection, which simplifies the overall structure of the device and facilitates the synchronous installation and disassembly of the DC power supply module 7 and the modular testing box 14, thereby improving the convenience of device assembly and maintenance.

[0044] The output of the comparator module is equipped with standardized terminals, which are DB9 type interfaces. The DB9 type interfaces are electrically connected to the DI module of the PLC control system or external alarm devices through shielded cables. The DB9 type standardized terminals and shielded cables ensure stable signal transmission and anti-interference, facilitate quick docking with PLC or external alarm devices, and improve the reliability and compatibility of the device's signal output.

[0045] See Figure 1 and Figure 2 The specific steps of the air replenishment device for detecting moisture content in this embodiment are as follows: Step 1: Construct a humidity sensor based on a PVA film; Step 1.1: Set up a sensor placement area in the air inlet pipe 2 of the air replenishment device. This area includes a pre-treated PVA humidity-sensitive film 4 (polyvinyl alcohol), which is fixed between the dual electrode structures 5 to form a resistive humidity sensor assembly 3. Step 1.2: The PVA moisture-sensitive membrane 4 is sensitive to moisture. After absorbing moisture, its conductivity increases and its resistance decreases. This change is captured by the electrodes at both ends and outputs the corresponding switching signal. Step 1.3: The surface of the PVA humidity-sensitive membrane 4 is in full contact with the air. The installation position is selected near the first air inlet in the airflow path to ensure that the detected gas is in its original humid state before entering the air supply valve. Step 2: Set up the signal processing and alarm circuit; Step 2.1: Connect the electrode signals from both ends of the PVA humidity-sensitive film 4 to the operational amplifier circuit (resistive voltage divider + comparator + amplifier structure) to amplify and shape the changes and convert them into a stable voltage output; (1) When the moisture content of the gas in the pipeline is normal, the resistance of the PVA humidity sensor is 10MΩ; Voltage follower U1 output voltage = =U2 positive input voltage; U2 negative input voltage = ; When the positive input voltage of U2 is less than the negative input voltage of U2, the output of U2 is 0. (2) When the moisture content of the gas in the pipeline is abnormal, the resistance of the PVA humidity sensor is 0.1MΩ; Voltage follower U1 output voltage = =U2 positive input voltage; U2 negative input voltage = ; When the positive input voltage of U2 is greater than the negative input voltage of U2, the output of U2 is 24V. Step 2.2: The signal enters the comparator circuit and is compared with the voltage corresponding to the preset moisture content threshold. When the humidity reaches or exceeds the threshold, the comparator outputs a high level. Step 2.3: The entire circuit can be powered by 24V DC, has anti-interference capability, and can be embedded into the modular detection box 14 in a modular manner; Step 3: Introduce visual aids to help judge the materials; Step 3.1: Color-changing silicone is built into the lower section of the resistive humidity sensor assembly 3. Its color changes significantly with the ambient humidity, making it easy for operators to judge with the naked eye. Step 3.2: The material is placed inside the transparent section of the air intake pipe 2, so that on-site personnel can observe the water content without disassembly, providing auxiliary reference for maintenance; Step 4: Implement both automatic and manual monitoring functions; Step 4.1: The system can be connected to an existing PLC or automatic control system. The output signal is connected to the PLC's DI module for alarm monitoring. When the PVA membrane detects a high humidity signal, it can be linked to cut off the gas supply solenoid valve or start the drying system. Step 4.2: Simultaneously, the system can prompt operators to intervene via a touchscreen or monitoring system to ensure system redundancy and reliability.

[0046] See Figure 1 and Figure 2 In this embodiment, the device has high sensitivity and fast response speed. It uses a polyvinyl alcohol (PVA) humidity-sensitive membrane 4 as the core detection element. Compared with traditional metal oxide or humidity-sensitive ceramic materials, the PVA humidity-sensitive membrane 4 is more sensitive to low concentrations of moisture and can quickly adsorb moisture in the air, resulting in a significant change in resistance.

[0047] See Figure 1 and Figure 2 In this embodiment, the structure is simple, easy to integrate and modify. The detection system is based on a dual electrode + PVA membrane, which is compact and has no moving parts. It is easy to embed into the existing gas supply valve pipeline. At the same time, this device does not require complex sensor modules or external laser / infrared detectors, further reducing system cost and size.

[0048] See Figure 1 and Figure 2In this embodiment, dual monitoring is adopted, which has a high degree of redundancy. The addition of color-changing materials provides an intuitive means of judgment. The electrical signal output is integrated with the PLC control system to realize a "visual + automatic" dual redundancy monitoring mechanism, thereby improving safety and reliability.

[0049] See Figure 1 and Figure 2 In this embodiment, the shortcomings of existing air replenishment systems are effectively compensated. Traditional air replenishment devices cannot detect the moisture content of the air source in real time and rely solely on air source processing equipment, which poses a risk of residual moisture entering. This device performs online monitoring at the front end of the air replenishment valve, which can effectively prevent moisture contamination from entering the oil tank and hydraulic system.

[0050] See Figure 1 and Figure 2 In this embodiment, it has alarm and linkage capabilities. The output signal can be used to trigger alarms, link valves to close, dryers to start and other logic, which is conducive to realizing unattended automated operation.

[0051] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A gas replenishment device for detecting moisture content, comprising a gas replenishment valve body (1) and an air inlet pipe (2) connected to the gas replenishment valve body (1), characterized in that: It also includes a resistive humidity sensor assembly (3), which is disposed near the first section of the air inlet of the air inlet pipe (2). The resistive humidity sensor assembly (3) includes a PVA humidity-sensitive film (4) and a dual-electrode structure (5). The PVA humidity-sensitive film (4) is fixed between the dual-electrode structures (5), and the surface of the PVA humidity-sensitive film (4) is in full contact with the airflow in the air inlet pipe (2). The signal processing circuit (6) is electrically connected to the dual-electrode structure (5), and the signal processing circuit (6) includes an operational amplifier module and a comparison module; DC power supply module (7), which provides 24V DC power to the signal processing circuit (6); After the PVA moisture-sensitive membrane (4) absorbs moisture, its resistance value decreases. The dual-electrode structure (5) captures the change in resistance value and outputs an electrical signal to the operational amplifier module. The operational amplifier module amplifies and shapes the electrical signal and outputs a stable voltage signal to the comparison module. The comparison module compares the stable voltage signal with the reference voltage signal corresponding to the preset moisture content threshold. When the stable voltage signal is greater than the reference voltage signal, the comparison module outputs a high level to trigger an alarm.

2. The gas replenishment device for detecting moisture content according to claim 1, characterized in that: The air intake pipe (2) is provided with a transparent observation section (8) downstream of the resistive humidity sensor assembly (3). The transparent observation section (8) contains a moisture-sensitive color-changing silicone, and the color of the moisture-sensitive color-changing silicone changes with the humidity of the gas in the air intake pipe (2).

3. The gas replenishment device for detecting moisture content according to claim 2, characterized in that: The operational amplifier module includes a voltage follower U1(9), and the comparator module includes a comparator U2(10); The signal processing circuit (6) further includes a first voltage divider resistor R1 (11), a second voltage divider resistor R2 (12), and a third voltage divider resistor R3 (13); The input terminal of the voltage follower U1 (9) is electrically connected to the output terminal of the dual electrode structure (5) and one end of the first voltage divider resistor R1 (11), and the other end of the first voltage divider resistor R1 (11) is grounded. The positive input terminal of the comparator U2 (10) is electrically connected to the output terminal of the voltage follower U1 (9). The negative input terminal of the comparator U2 (10) is electrically connected to one end of the second voltage divider resistor R2 (12) and one end of the third voltage divider resistor R3 (13). The other end of the second voltage divider resistor R2 (12) is electrically connected to the output terminal of the DC power supply module (7). The other end of the third voltage divider resistor R3 (13) is grounded. The resistance values ​​of the first voltage divider resistor R1 (11), the second voltage divider resistor R2 (12), and the third voltage divider resistor R3 (13) are all 5MΩ.

4. The gas replenishment device for detecting moisture content according to claim 1, characterized in that: It also includes a PLC control system, which is equipped with a DI module, and the output of the comparator module is electrically connected to the DI module; When the comparison module outputs a high level, the PLC control system can shut off the gas supply solenoid valve of the gas supply valve body (1) or start the gas drying system matched with the gas inlet pipeline (2).

5. The gas replenishment device for detecting moisture content according to claim 1, characterized in that: The dual-electrode structure (5) consists of two vertically arranged metal electrodes, and the PVA humidity-sensitive membrane (4) is fastened between the two metal electrodes.

6. The air-injection device for detecting moisture content according to claim 1, characterized in that: The signal processing circuit (6) is integrated into the modular detection box (14), which can be detachably installed on the outside of the housing of the air supply valve body (1) or embedded in the housing of the air supply valve body (1).

7. The air-injection device for detecting moisture content according to claim 1, characterized in that: The PVA humidity-sensitive film (4) is a polyvinyl alcohol film that has undergone cross-linking modification. The thickness of the PVA humidity-sensitive film (4) is 0.1 mm to 0.5 mm, and the surface of the PVA humidity-sensitive film (4) is provided with micron-sized air pores.

8. The air-injection device for detecting moisture content according to claim 1, characterized in that: The sensor placement area of ​​the air intake pipe (2) is an inwardly recessed annular step structure. The dual electrode structure (5) is fixed to the inner wall of the annular step by bolts. The outer periphery of the PVA humidity-sensitive membrane (4) is sealed and abutted against the step surface of the annular step.

9. The air-injection device for detecting moisture content according to claim 6, characterized in that: The DC power supply module (7) is integrated into the modular testing box (14). The side wall of the modular testing box (14) is provided with a snap-fit ​​structure that is compatible with the housing of the air supply valve body (1). The modular testing box (14) is detachably connected to the housing of the air supply valve body (1) through the snap-fit ​​structure.

10. The gas replenishment device for detecting moisture content according to claim 1, characterized in that: The output of the comparator module is equipped with a standardized terminal block, which is a DB9 type interface. The DB9 type interface is electrically connected to the DI module of the PLC control system or an external alarm device through a shielded cable.

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