Multi-parameter density micro-water sensor and measuring method

Abstract

The invention provides a multi-parameter density micro-water sensor and a measuring method, and particularly relates to the technical field of environment monitoring sensors, and the sensor comprises a housing, a power supply module, a sensor module and a wireless communication module. The shell is composed of a top shell and a bottom shell, a mounting cavity in vertical layered layout is formed, and the bottom shell is embedded into a to-be-detected medium pipeline. A power supply module, a wireless communication module and a sensor module are arranged in the mounting cavity from top to bottom. The power supply module comprises a solar panel and a storage battery, and dual-mode power supply is achieved. The sensor module comprises a density sensor probe, a micro-water sensor probe, a temperature sensor probe and a pressure sensor probe which are arranged in the independent cavities respectively, and the inner walls are covered with conductive material coatings and separated through insulating partition plates. According to the sensor, through the layered shielding structure and the independent cavity design, electromagnetic and physical interference during integration of multiple sensors is reduced, the measurement precision and the equipment reliability are improved, and the microminiaturization characteristic is maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental monitoring sensors, and more particularly, to a multi-parameter density and micro-water sensor and a measurement method. Background Art

[0002] In the field of high-precision environmental monitoring of key parameters such as micro-water and density, wireless integrated sensors have become the mainstream direction due to their flexible deployment and strong real-time performance. However, when multiple sensors (such as micro-water, density, temperature) are integrated into a single device, due to the superposition of electromagnetic radiation, too close physical probe spacing, and medium flow interference, serious signal crosstalk occurs, and the measurement error increases significantly (in typical scenarios, the humidity error exceeds ±5%). This problem is particularly prominent in miniaturized devices, and traditional anti-interference means are difficult to balance the contradiction between accuracy and volume.

[0003] The prior art mainly alleviates interference through two methods: 1) increasing the physical isolation distance (such as a split probe design), but this causes the device volume to increase exponentially and cannot meet the installation requirements in narrow spaces; 2) software filtering algorithms (such as frequency-domain noise suppression), but they have poor adaptability to high-frequency random interference (such as capacitance coupling noise between probes) and rely on high-computing power chips, resulting in a sharp increase in power consumption and cost. In addition, although using a metal shell for overall shielding can suppress external electromagnetic interference, it cannot solve the cross-interference between internal sensors, and the weight of the shielding body affects the deployment convenience.

[0004] In summary, how to solve the problem of the decrease in measurement accuracy caused by electromagnetic and physical coupling interference inside multiple sensors through structural innovation in miniaturized devices is a technical problem that urgently needs to be solved currently. Summary of the Invention

[0005] The main purpose of the present invention is to provide a multi-parameter density and micro-water sensor and a measurement method to solve the technical problem of how to solve the decrease in measurement accuracy caused by electromagnetic and physical coupling interference inside multiple sensors through structural innovation in miniaturized devices, so as to significantly reduce electromagnetic and physical interference during the integration of multiple sensors through a hierarchical shielding structure and an independent chamber design, improve the metering accuracy of the electric energy meter and the reliability of the device, and at the same time maintain the miniaturized characteristics.

[0006] To achieve the above object, the present invention provides a multi-parameter density and micro-water sensor and a measurement method.

[0007] In a first aspect, the present invention provides a multi-parameter density and micro-water sensor, the sensor comprising: a housing, a power supply module, a sensor module, and a wireless communication module, the housing comprising a top shell and a bottom shell, a vertically layered layout installation cavity being formed between the top shell and the bottom shell, the bottom shell being embedded inside a pipeline of a medium to be measured and being in direct contact with the medium to be measured; The installation cavity from top to bottom comprises: The top layer is provided with the power supply module, which includes a solar panel and a storage battery. The solar panel is embedded in the outer surface of the top shell. The middle layer is provided with the wireless communication module, and a metal shielding layer is provided between the middle layer and the top layer. The bottom layer is provided with the sensor module and a plurality of independent chambers. The sensor module includes a density sensor probe, a micro water sensor probe, a temperature sensor probe, and a pressure sensor probe. The density sensor probe, the micro water sensor probe, the temperature sensor probe, and the pressure sensor probe are respectively arranged in the independent chambers. The inner wall of the independent chamber is covered with a conductive material coating and separated by an insulating partition. The density sensor probe has a conical probe structure penetrating the bottom shell, and the conical probe structure extends into the measured medium in the pipeline. The sensing surface of the micro water sensor probe contacts the measured medium through the breathable micropores of the bottom shell. The temperature sensor probe is connected to the inner wall of the bottom shell through thermal conductive silica gel. The pressure sensor probe is a corrugated diaphragm structure embedded in the outer surface of the bottom shell. The storage battery is electrically connected to the wireless communication module and the sensor module respectively, and the wireless communication module is signal-connected to the sensor module.

[0008] Specifically, a hydrophobic breathable membrane is provided in the breathable micropores, and the contact angle of the hydrophobic breathable membrane is greater than 150°.

[0009] Specifically, the inner side of the corrugated diaphragm structure is communicated with the corresponding independent chamber through a pressure guiding tube, and the inner diameter of the pressure guiding tube is 0.5 - 1.0 mm.

[0010] Specifically, an aerogel thermal insulation layer is provided between the thermal conductive silica gel and the inner wall of the bottom shell.

[0011] Specifically, the metal shielding layer is made of copper-nickel alloy, with a thickness of 0.5 - 1.2 mm, and the metal shielding layer is bonded to the PCB substrate of the wireless communication module through conductive adhesive.

[0012] In a second aspect, the present invention provides a measurement method based on the multi-parameter density and micro water sensor described in the first aspect, including the following steps: S1. Collect light energy through the solar panel on the outer surface of the top shell and convert it into electrical energy, and store it in the storage battery to form dual-mode power supply. S2. Start the sensor module, and perform multi-parameter synchronous measurement through each sensor probe separately arranged in the independent chamber: S21. Use the density sensor probe with a conical probe structure to penetrate the bottom shell to measure the density of the measured medium. S22. Make the probe of the micro - water sensor contact the water molecules of the medium to be measured through the breathable micropores of the bottom shell; S23. Conduct the temperature of the medium to be measured to the temperature sensor probe through thermally conductive silica gel; S24. Sense the pressure change of the medium to be measured through the pressure sensor probe with a corrugated diaphragm structure; S3. Independently process the signals of each sensor at the bottom layer, implement conductive shielding through a conductive material coating, and implement physical isolation through an insulating partition to suppress electromagnetic and mechanical coupling interference between sensors; S4. Transmit the processed sensing signals to the middle layer. After signal isolation through a metal shielding layer, the wireless communication module performs data encoding and wireless transmission; S5. Monitor the battery power in real - time. When the light is insufficient, automatically switch to the battery - powered mode to maintain continuous operation.

[0013] Specifically, the independent processing in chamber - by - chamber in step S3 includes: Perform temperature compensation and calibration on the impedance signal of the density sensor probe; Perform medium - pressure correlation correction on the capacitance value of the micro - water sensor probe; Adopt a time - diversity method to control the sampling timing of each sensor with staggered peaks.

[0014] Specifically, the wireless transmission in step S4 adopts an adaptive frequency - hopping mechanism. When the electromagnetic interference inside the metal shielding layer exceeds the threshold, automatically switch the communication frequency band.

[0015] The multi - parameter density and micro - water sensor and measurement method provided by this application. The sensor includes a housing, a power supply module, a sensor module, and a wireless communication module. The housing consists of a top shell and a bottom shell, forming an installation cavity with a vertical layered layout. The bottom shell is embedded in the pipeline of the medium to be measured. The installation cavity is respectively provided with a power supply module, a wireless communication module, and a sensor module from top to bottom. The power supply module includes a solar panel and a battery, realizing dual - mode power supply of solar energy and battery. The sensor module includes density, micro - water, temperature, and pressure sensor probes. Each probe is placed in an independent chamber. The inner wall of the chamber is covered with a conductive material coating and separated by an insulating partition to reduce electromagnetic and physical coupling interference. The wireless communication module is signal - connected to the sensor module to realize wireless data transmission. This sensor, through a layered shielding structure and an independent chamber design, significantly reduces the interference during multi - sensor integration, improves the measurement accuracy and equipment reliability, and at the same time maintains the miniaturization characteristics. Description of the Drawings

[0016] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is an overall schematic diagram of the multi-parameter density micro water sensor provided by this application; Figure 2 is a schematic flow diagram of the measurement method based on the multi-parameter density micro water sensor provided by this application.

[0017] 10. Housing; 11. Top shell; 12. Bottom shell; 101. Top layer; 102. Intermediate layer; 103. Bottom layer; 20. Power supply module; 21. Solar panel; 22. Storage battery; 30. Sensor module; 31. Independent chamber; 32. Conductive material coating; 33. Insulating partition; 34. Density sensor probe; 35. Micro water sensor probe; 36. Temperature sensor probe; 361. Thermal conductive silica gel; 37. Pressure sensor probe; 371. Pressure guiding tube; 40. Wireless communication module; 60. Metal shielding layer; 121. Air permeable micropores; 122. Hydrophobic breathable membrane.

[0018] Through the above-mentioned accompanying drawings, the clear embodiments of this application have been shown, and there will be more detailed descriptions hereinafter. These drawings and written descriptions are not intended to limit the scope of the concept of this application in any way, but to explain the concept of this application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0019] To make the objectives, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the accompanying drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

[0020] The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present invention and the above-mentioned accompanying drawings are used to distinguish similar objects and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order different from those illustrated or described here.

[0021] In the present invention, words such as "exemplary" or "for example" are used to represent examples, illustrations or explanations. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0022] The multi-parameter density and micro-water sensor and measurement method provided in this application, the sensor includes a housing, a power supply module, a sensor module and a wireless communication module. The housing is composed of a top shell and a bottom shell to form a vertically layered installation cavity, and the bottom shell is embedded in the pipeline of the medium to be measured. The power supply module includes a solar panel and a storage battery to achieve dual-mode power supply. The sensor module includes density, micro-water, temperature and pressure sensor probes, which are respectively placed in independent chambers. The inner wall of the chamber is covered with a conductive material coating and separated by an insulating partition. The wireless communication module is signal-connected to the sensor module. Through the layered shielding structure and independent chamber design, electromagnetic and physical interference during multi-sensor integration is reduced, measurement accuracy and equipment reliability are improved, and miniaturization characteristics are maintained.

[0023] The technical solution of this application and how the technical solution of this application solves the above technical problems will be described in detail below with specific embodiments. These several specific embodiments below can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of this application will be described below with reference to the accompanying drawings.

[0024] As Figure 1 shown, the multi-parameter density and micro-water sensor provided in this embodiment, the sensor includes: a housing 10, a power supply module 20, a sensor module 30 and a wireless communication module 40. The housing 10 includes a top shell 11 and a bottom shell 12. A vertically layered layout installation cavity is formed between the top shell 11 and the bottom shell 12. The bottom shell 12 is embedded inside the pipeline of the medium to be measured and is in direct contact with the medium to be measured; The installation cavity from top to bottom includes: The top layer 101 is provided with the power supply module 20. The power supply module 20 includes a solar panel 21 and a storage battery 22. The solar panel 21 is embedded in the outer surface of the top shell 11; The middle layer 102 is provided with the wireless communication module 40. A metal shielding layer 60 is provided between the middle layer 102 and the top layer 101; The bottom layer 103 is provided with the sensor module 30 and multiple independent chambers 31. The sensor module 30 includes a density sensor probe 34, a micro water sensor probe 35, a temperature sensor probe 36, and a pressure sensor probe 37. The density sensor probe 34, the micro water sensor probe 35, the temperature sensor probe 36, and the pressure sensor probe 37 are respectively arranged in the independent chambers 31. The inner wall of the independent chamber 31 is covered with a conductive material coating 32 and separated by an insulating partition 33; The density sensor probe 34 has a conical probe structure penetrating the bottom shell 12, and the conical probe structure extends into the measured medium in the pipeline; The sensing surface of the micro water sensor probe 35 contacts the measured medium through the air permeable micropores 121 of the bottom shell 12; The temperature sensor probe 36 is connected to the inner wall of the bottom shell 12 through a heat conductive silica gel 361; The pressure sensor probe 37 is a corrugated diaphragm structure embedded in the outer surface of the bottom shell 12; The storage battery 22 is electrically connected to the wireless communication module 40 and the sensor module 30 respectively, and the wireless communication module 40 is signal-connected to the sensor module 30.

[0025] In specific implementation: The multi-parameter density and micro water sensor provided in this embodiment includes a housing 10, a power supply module 20, a sensor module 30, and a wireless communication module 40. The housing 10 includes a top shell 11 and a bottom shell 12. The top shell 11 and the bottom shell 12 are fixedly connected by M6 stainless steel bolts evenly distributed circumferentially to form an installation cavity with a vertical layered layout. The contact surface between the top shell 11 and the bottom shell 12 is processed with an annular sealing groove with a depth of 0.5 mm and filled with a fluororubber sealing ring. The outer surface of the bottom shell 12 is processed with an M30×1.5 external thread structure, and the bottom surface of the bottom shell 12 is polished to form a medium contact surface with a Ra 0.8 roughness, so as to realize the sealed embedded connection with the measured medium pipeline.

[0026] The installation cavity is divided into three layers from top to bottom: a top layer 101, a middle layer 102, and a bottom layer 103. The power supply module 20 is installed in the top layer 101. The power supply module 20 includes a solar panel 21 made of single crystal silicon and a lithium polymer storage battery 22. The solar panel 21 is adhesively fixed on the outer surface of the top shell 11 through a weather-resistant epoxy resin adhesive layer. The positive and negative electrodes of the solar panel 21 are connected to the DC 5V charging interface of the storage battery 22 through copper wires with a cross-sectional area of 0.75 mm 2 The output end of the storage battery 22 is electrically connected to the wireless communication module 40 in the middle layer 102 and the sensor module 30 in the bottom layer 103 through a 18AWG copper core power supply wire wrapped with a PVC insulating sheath, where the red wire connects the positive electrode of the storage battery 22 to the +12V power supply end of each module, and the black wire connects to the common grounding end.

[0027] A wireless communication module 40 is installed inside the middle layer 102. A T2 copper foil metal shielding layer 60 with a thickness of 0.5 mm is provided between the middle layer 102 and the top layer 101. The edge of the copper foil is soldered to the annular groove on the inner wall of the top shell 11 to form a full-circumference continuous conductive connection. The wireless communication module 40 includes a Wi-Fi communication unit that supports the IEEE 802.11 b / g / n protocol in the 2.4 GHz frequency band. This unit integrates a dual-core 32-bit RISC processor and has a built-in TCP / IP protocol stack. The antenna part adopts a 1 / 4 wavelength inverted F structure and externally connects an omnidirectional antenna through an SMA interface. The RS-485 communication interface of the wireless communication module 40 is connected to the sensor module 30 on the bottom layer 103 through a four-core shielded twisted pair cable, and the shielding layer is conducted to the copper grounding post on the bottom shell 12 to reduce electromagnetic interference during signal transmission.

[0028] A sensor module 30 and four cylindrical independent chambers 31 are arranged inside the bottom layer 103. The inner wall of the independent chamber 31 is covered with a chemical silver-plated copper conductive material coating 32 with a thickness of 50 μm. Adjacent chambers are mechanically isolated by a polytetrafluoroethylene insulating partition 33 with a thickness of 3 mm, forming a double protection structure of electromagnetic shielding and physical vibration isolation. The sensor module 30 includes the following components: Density sensor probe 34: It has a 316L stainless steel conical probe structure with a cone angle of 60°. The probe penetrates through the Φ3 mm central through-hole of the bottom shell 12 and extends into the measured medium in the pipeline. The gap between the probe and the through-hole is filled with a fluororubber sealing ring with a Shore hardness of 70 to achieve medium penetration barrier; Micro water sensor probe 35: The sensing surface fits the Φ0.1 mm array of breathable micropores 121 on the bottom shell 12. The breathable micropores are filled with an expanded polytetrafluoroethylene hydrophobic breathable membrane with a thickness of 0.05 mm, allowing gas molecules to pass through and blocking liquid media; Temperature sensor probe 36: It is bonded to the inner wall of the bottom shell 12 through a thermal conductive silica gel 361 with a thickness of 2 mm and a thermal conductivity of 3.5 W / (m·K). The bottom surface of the thermal conductive silica gel 361 is cleaned with acetone and chemically bonded to the surface of the anodized aluminum to achieve a thermal response time of ≤0.3 seconds; Pressure sensor probe 37: It adopts a silicon piezoresistive corrugated diaphragm structure and is embedded in the outer surface of the bottom shell 12. The outer surface of the diaphragm is sprayed with a polyimide anti-corrosion layer with a thickness of 25 μm, with a measurement range covering 0 - 1 MPa and outputting a 0.5 - 4.5 V linear analog signal.

[0029] The +12V output terminal of the storage battery 22 supplies power to the density sensor probe 34, the micro water sensor probe 35, the temperature sensor probe 36, and the pressure sensor probe 37 respectively through four groups of 22AWG copper wires connected in parallel. The signal output terminals of each probe are connected to the signal conditioning circuit board through independent shielded cables. This circuit board integrates an AD620 instrumentation amplifier to amplify the sensor signal by 100 times, and filters it with a second-order Butterworth filter with a bandwidth of 0.1 - 100Hz. The processed signal is transmitted to the wireless communication module 40 through the RS-485 protocol.

[0030] The solar panel 21 on the outer surface of the top shell 11 generates a maximum open-circuit voltage of 18V under the standard light intensity of 1000W / m 2 condition, and is converted into direct current of 12V ± 0.5V through a DC-DC buck circuit and stored in the storage battery 22. The copper foil surface of the metal shielding layer 60 is passivated to form a cuprous oxide protective film, which provides an electromagnetic shielding effectiveness of ≥60dB in the frequency band of 1MHz - 3GHz, blocking the high-frequency interference of the power supply module 20 to the wireless communication module 40. The conductive material coating 32 of the independent chamber 31 is connected to the grounding terminal of the bottom shell 12 through a 0.5mm 2 copper braid to form a Faraday cage shielding structure, reducing the electromagnetic crosstalk voltage between chambers to below 5mV. At the same time, the polytetrafluoroethylene insulating partition 33 increases the mechanical vibration transmission loss to -40dB.

[0031] In this embodiment, the linear distance between the power supply module 20 and the sensor module 30 is controlled within 35mm ± 0.5mm through a vertical layered layout. Combining the composite shielding design of the metal shielding layer 60 and the independent chamber 31, the multi-sensor signal crosstalk is reduced to below -90dB. The conical probe structure of the density sensor probe 34 realizes the density measurement within the range of the dynamic viscosity of the medium from 0.1 - 1000cP, with a resolution of 0.01kg / m 3 ; The breathable microporous structure of the micro water sensor probe 35 effectively blocks particles with a particle size > 5μm while maintaining an air ventilation volume of 1.5L / min. The overall structure has a diameter of 50mm ± 0.5mm and a height of 75mm, meeting the embedded installation requirements of a DN50 standard pipeline. This multi-parameter density and micro water sensor solves the technical problem of how to solve the decline in measurement accuracy caused by electromagnetic and physical coupling interference inside multi-sensors in a miniaturized device. Thus, through a layered shielding structure and an independent chamber design, the electromagnetic and physical interference during multi-sensor integration is significantly reduced, improving the metering accuracy of the watt-hour meter and the reliability of the device, while maintaining the miniaturized characteristics.

[0032] The following are preferred specific embodiments: Specifically, a hydrophobic breathable membrane 122 is provided inside the breathable micropore 121, and the contact angle of the hydrophobic breathable membrane 122 is greater than 150°.

[0033] Specifically, the inner side of the corrugated diaphragm structure is connected to the corresponding independent chamber 31 through a pressure guiding pipe 371, and the inner diameter of the pressure guiding pipe 371 is 0.5 - 1.0 mm.

[0034] Specifically, an aerogel heat insulation layer is provided between the heat-conducting silica gel 361 and the inner wall of the bottom shell 12.

[0035] Specifically, the material of the metal shielding layer 60 is copper-nickel alloy, with a thickness of 0.5 - 1.2 mm, and the metal shielding layer 60 is bonded to the PCB substrate of the wireless communication module 40 through conductive adhesive.

[0036] The following are the refined technical features of the preferred specific embodiments: 1. Integrated structure of the breathable micropores 121 and the hydrophobic breathable membrane 122 The breathable micropores 121 of the bottom shell 12 are internally embedded with an expanded polytetrafluoroethylene hydrophobic breathable membrane 122 with a thickness of 0.05 mm. The hydrophobic breathable membrane 122 is fixed on the inner wall step surface of the breathable micropores 121 through a hot pressing welding process. The surface of the hydrophobic breathable membrane 122 is treated by plasma fluorination to form a superhydrophobic property with a contact angle of 152° ± 2°. The pore size distribution of the hydrophobic breathable membrane 122 is 0.1 - 0.3 μm, allowing gas molecules to pass through and blocking the penetration of liquid media. The sensing surface of the micro water sensor probe 35 is crimped with the outer surface of the hydrophobic breathable membrane 122 through a fluorosilicone rubber sealing ring to ensure that the water vapor molecules in the medium to be measured diffuse unidirectionally through the hydrophobic breathable membrane 122 to the capacitive sensing unit of the micro water sensor probe 35.

[0037] 2. Connection relationship of the pressure guiding pipe 371 of the corrugated diaphragm structure The inner side of the corrugated diaphragm structure of the pressure sensor probe 37 is welded with a 316L stainless steel pressure guiding pipe 371 with an inner diameter of 0.8 mm ± 0.1 mm. The other end of the pressure guiding pipe 371 penetrates through the side wall of the independent chamber 31 and is sealed by laser welding. The axis of the pressure guiding pipe 371 forms a 45° angle with the outer surface of the bottom shell 12. The inner cavity of the pressure guiding pipe 371 is filled with silicone oil with a viscosity of 50 cSt as the pressure transmission medium. A nickel-based alloy corrugated compensator with a thickness of 0.2 mm is provided at the connection between the pressure guiding pipe 371 and the independent chamber 31 to compensate for the deformation of ±0.15 mm caused by thermal expansion.

[0038] 3. Composite structure of the heat-conducting silica gel 361 and the aerogel heat insulation layer A silica aerogel thermal insulation layer with a thickness of 1.5 mm is provided between the temperature sensor probe 36 and the inner wall of the bottom case 12. The thermal conductivity of the aerogel thermal insulation layer is 0.018 W / (m·K), and the porosity is 92%. The thermal conductive silica gel 361 is coated on the outer surface of the aerogel thermal insulation layer. The thickness of the thermal conductive silica gel 361 is 2.0 mm ± 0.1 mm, and it is formed by curing a two-component addition-curing silicone rubber (A:B = 1:1 mass ratio) at 80°C for 2 h. The thermal conductive silica gel 361 and the anodic aluminum oxide layer on the inner wall of the bottom case 12 are chemically bonded through a silane coupling agent KH-550.

[0039] 4. Installation details of the metal shielding layer 60 The metal shielding layer 60 between the intermediate layer 102 and the top layer 101 is made of CuNi10Fe1Mn copper-nickel alloy by rolling, with a thickness of 0.8 mm ± 0.05 mm. The surface of the metal shielding layer 60 is sandblasted to form a Ra3.2 roughness. The lower surface of the metal shielding layer 60 is bonded to the FR-4 material PCB substrate of the wireless communication module 40 through conductive silver glue (silver content 85 wt%). The coating thickness of the conductive silver glue is 0.1 mm, and the volume resistivity after curing is ≤5×10 -4 Ω·cm. The upper edge of the metal shielding layer 60 is mechanically connected to the annular grounding copper strip on the inner wall of the top case 11 through an M3 copper screw, and the screw pitch is 15 mm ± 0.5 mm.

[0040] Effects that can be achieved by preferred specific embodiments: The 152° contact angle characteristic of the hydrophobic and breathable membrane 122 makes the contact angle of liquid water exceed the critical threshold, and still maintains the function of breathable but not permeable to liquid under a pressure difference of 10 bar, ensuring that the micro water sensor probe 35 only detects gaseous moisture; The 45° inclined layout of the pressure guiding tube 371 reduces the impact of medium flow. The silicone oil transfer medium enables the corrugated diaphragm of the pressure sensor probe 37 to maintain a temperature drift of ±0.05% FS / °C in the range of -40°C to 125°C; The aerogel thermal insulation layer reduces the heat flow conducted from the bottom case 12 to the temperature sensor probe 36 by 82%. Combining with the thermal conductivity of 3.5 W / (m·K) of the thermal conductive silica gel 361, the temperature response time is shortened from 1.2 s to 0.3 s; The shielding effectiveness of the copper-nickel alloy metal shielding layer 60 in the 2.4 GHz frequency band reaches 78 dB. The conductive silver glue bonding makes the grounding impedance of the PCB substrate ≤0.1 Ω, blocking the common-mode interference of the power supply module 20 to the wireless communication module 40.

[0041] As Figure 2 shown, a measurement method of a multi-parameter density micro water sensor provided by this embodiment is based on Figure 1 the embodiment, including the following steps: S1. Collect light energy through the solar panel 21 on the outer surface of the top shell 11, convert it into electrical energy, and store it in the battery 22 to form dual-mode power supply; S2. Activate the sensor module 30, and perform multi-parameter synchronous measurement through each sensor probe separately arranged in the independent chamber 31: S21. Use the density sensor probe 34 with a conical probe structure to penetrate the bottom shell 12 to measure the density of the medium to be measured; S22. Make the micro water sensor probe 35 contact the water molecules of the medium to be measured through the breathable micropores 121 of the bottom shell 12; S23. Conduct the temperature of the medium to be measured to the temperature sensor probe 36 through the thermal conductive silica gel 361; S24. Sense the pressure change of the medium to be measured through the pressure sensor probe 37 with a corrugated diaphragm structure; S3. Independently process the signals of each sensor in the bottom layer 103, implement conductive shielding through the conductive material coating 32, and implement physical isolation through the insulating partition 33 to suppress electromagnetic and mechanical coupling interference between sensors; S4. Transmit the processed sensing signals to the middle layer 102, perform signal isolation through the metal shielding layer 60, and then perform data encoding and wireless transmission by the wireless communication module 40; S5. Monitor the battery power of the battery 22 in real time, and automatically switch to the battery 22 power supply mode to maintain continuous operation when the light is insufficient.

[0042] When implementing this measurement method, it specifically includes the following steps: Step S1: Dual-mode power supply initialization When the light intensity of the monocrystalline silicon solar panel 21 on the outer surface of the top shell 11 ≥ 200W / m 2 At this time, adjust the working voltage to 17.5V ± 0.5V through the MPPT (maximum power point tracking) algorithm, and store the electrical energy in the lithium polymer battery 22 through the BQ24650 type charging controller. The MPPT algorithm adopts the perturbation and observation method, measures the voltage-current characteristic curve of the solar panel 21 every 5 seconds, and locks the maximum power point through the gradient descent method. The overcharge protection threshold of the battery 22 is set to 12.6V, the over-discharge protection threshold is set to 10.8V, and the charge and discharge cycle times ≥ 2000 times.

[0043] Function and effect: Improve the photoelectric conversion efficiency to more than 22% through the MPPT algorithm. The dual-mode power supply system can maintain a 72-hour endurance under continuous rainy conditions, and the temperature coefficient compensation of the charging controller ensures the charging stability in the environment of -20°C to 60°C.

[0044] Step S2: Multi-parameter synchronous measurement S21 Medium density measurement: The conical probe of the density sensor probe 34 generates mechanical vibrations of 0.1 - 10 kHz in the medium, and the density value is calculated by detecting the change in vibration damping coefficient ΔC (unit: pF). Calculation formula: , where K is the probe shape coefficient (when the cone angle is 60°, K = 0.785), is the vacuum resonance frequency (calibration value 125 kHz), is the measured frequency.

[0045] S22 Micro - water content measurement: The micro - water sensor probe 35 detects the dielectric constant difference on both sides of the hydrophobic breathable membrane 122 through the capacitive measurement principle. The distance between the probe electrodes is 0.1 mm, and a 1 MHz sine - wave excitation signal is applied. According to the relationship between the capacitance change ΔC and the moisture concentration: PPM = α × ln(ΔC / ), α = 0.68 (calibration coefficient of the polytetrafluoroethylene membrane), is the reference capacitance value in the dry state.

[0046] S23 Temperature measurement: The PT100 platinum resistance of the temperature sensor probe 36 detects the temperature of the inner wall of the bottom shell 12, is powered by a four - wire constant - current source (current 1 mA), and nonlinear correction is performed using the Callendar - Van Dusen equation: , coefficient A = 3.9083×10 -3 / ℃, B = - 5.775×10 -7 / ℃ 2 , C = - 4.183×10 -12 / ℃ 4 (enabled when T ≤ 0℃), R(T) is the resistance value of the platinum resistance at temperature (unit: ℃) (unit: Ω), R 0 represents the nominal resistance value of the platinum resistance at 0℃ (unit: Ω).

[0047] S24 Pressure measurement: The deformation of the corrugated diaphragm of the pressure sensor probe 37 is converted into a voltage signal through a full - bridge strain gauge, and sampled using an HX711 type 24 - bit ADC. The pressure value is calculated as: P=(Vout×S) / G, where Vout refers to the original voltage signal output by the pressure sensor probe 37, with the unit of millivolt (mV), the sensitivity S = 2 mV / V, and the gain G = 128.

[0048] Function and effect: The four - parameter synchronous measurement period ≤ 100 ms, the density measurement resolution reaches 0.01 kg / m 3 , the lower limit of micro - water detection is 0.1 ppm, the temperature measurement error is ±0.1℃, and the pressure linearity is ±0.05% FS.

[0049] Step S3: Signal anti - interference processing Each sensor signal is amplified by a factor of 100 by an AD620 instrumentation amplifier in the independent chamber 31, and then high-frequency noise is filtered out by a second-order Butterworth low-pass filter (cutoff frequency 100 Hz, stopband attenuation -40 dB / dec). The grounding resistance between the conductive material coating 32 and the grounding terminal of the bottom shell 12 is ≤0.1 Ω, and the shielding effectiveness is ≥70 dB@1 MHz. The vibration transfer loss of the polytetrafluoroethylene insulating partition 33 is ≥30 dB, and the natural frequency is designed to be 1 kHz to avoid the working frequency band of the sensor.

[0050] Function and effect: The signal-to-noise ratio is increased to 80 dB, the crosstalk voltage between sensors is <5 mV, and the mechanical vibration coupling rate is reduced by 92%.

[0051] Step S4: Data encoding and transmission The processed sensing signal is converted into an RS-485 differential signal through the UART interface of STM32F407. The baud rate is set to 115200 bps. The data frame contains 8 data bits, 1 stop bit, and no parity check. The wireless communication module 40 encapsulates data using the TCP / IP protocol stack. A 16-bit CRC check code (polynomial 0x8005) is added to each frame of data and sent in the 2.4 GHz frequency band by DSSS (direct sequence spread spectrum) method. The transmit power is 20 dBm, and the receive sensitivity is -97 dBm.

[0052] Function and effect: The data transmission error rate is <10 -6 , the wireless transmission distance is ≥100 m (line-of-sight environment), the CRC check ensures data integrity, and the anti-interference ability of DSSS modulation reaches 15 dB.

[0053] Step S5: Power supply mode switching The voltage monitoring circuit of the storage battery 22 uses an LM393 voltage comparator, and the threshold voltage is set to 11.1 V (corresponding to 30% battery power). When it is detected that the voltage of the storage battery 22 is continuously lower than the threshold for 5 seconds, the switching circuit controls the IRF540N MOSFET to disconnect the input of the solar panel 21 and switches to the pure storage battery power supply mode. The voltage drop during the switching process is <0.2 V, and the switching time is <10 μs.

[0054] Function and effect: Achieve uninterrupted switching of the power supply mode. The deep discharge protection of the storage battery 22 extends the service life to more than 5 years, and the power supply ripple to the sensor module 30 during the switching process is <10 mVpp.

[0055] This measurement method improves the light energy utilization rate by 12% through the MPPT algorithm, compresses the multi-sensor synchronous sampling period to the 100ms level, makes the data packet loss rate lower than 0.01% through the combined transmission of RS-485 and DSSS, and the dual-mode power supply switching mechanism ensures that the device can continuously work for ≥72h in extreme environments. The overall measurement accuracy reaches the technical indicators of density ±0.05%, micro water ±1ppm, temperature ±0.2°C, and pressure ±0.1%FS.

[0056] The following are the preferred specific contents: Specifically, the separate chamber independent processing described in step S3 includes: Performing temperature compensation and calibration on the impedance signal of the density sensor probe 34; Performing medium pressure correlation correction on the capacitance value of the micro water sensor probe 35; Using time diversity to control the sampling timing of each sensor in a staggered manner.

[0057] Specifically, the wireless transmission described in step S4 adopts an adaptive frequency hopping mechanism. When the electromagnetic interference inside the metal shielding layer 60 exceeds the threshold, the communication frequency band is automatically switched.

[0058] The following are the specific embodiments of the preferred specific contents: 1. Specific implementation manner of the separate chamber independent processing in step S3 (1) Temperature compensation and calibration of the density sensor probe 34 After the impedance signal of the density sensor probe 34 is amplified 100 times by the AD8421 instrumentation amplifier, it is input into the ADC1 channel of the STM32F407 for sampling. The temperature compensation algorithm uses the cubic spline interpolation method to construct an impedance-temperature correction matrix: At three temperature points of 20°C, 50°C, and 80°C, measure the impedance reference value Z_ref(T) of the density sensor probe 34 in the standard medium.

[0059] Establish a piecewise compensation function: , where the coefficient a = 0.15Ω / °C, b = 0.002Ω / °C 2 , c = 0.0001Ω / °C 3 ( ).

[0060] Real-time collect the measured value T_act of the temperature sensor probe 36, and calculate the compensated impedance Z_comp = Z_meas - ΔZ(T_act), where Z_meas is the measured impedance value (that is, the uncompensated impedance value directly measured by the density sensor probe 34 under the real-time working condition, in ohms (Ω)), and ΔZ(T_act) is the temperature-related impedance offset (that is, the impedance change amount of the density sensor probe 34 caused by the current actual temperature T_act, in ohms (Ω)).

[0061] Function and effect: Eliminate the ±0.5% density measurement error caused by temperature drift, and make the deviation of the density value within the range of -40°C to 85°C ≤ ±0.02%.

[0062] (2)Capacitance pressure correction of the micro water sensor probe 35 The original capacitance value C_raw of the micro water sensor probe 35 is corrected through the following steps: The pressure correlation correction coefficient matrix adopts a linear regression model: C_corr = C_raw × [1 + β(P - P_ref)], where: β = 0.0015 / kPa (polytetrafluoroethylene membrane pressure deformation coefficient); P_ref = 101.325 kPa (standard atmospheric pressure reference); The real-time pressure value P is provided by the pressure sensor probe 37; The medium temperature compensation is achieved through a covariance matrix: C_final = C_corr × [1 - γ(T - T_ref)], γ = 0.0002 / °C (temperature influence factor), where: C_final: The final capacitance value after temperature-pressure double compensation, in picofarads (pF).

[0063] C_corr: The intermediate capacitance value that only completes the pressure correction, calculated by the formula C_corr = C_raw × [1 + β(P - P_ref)].

[0064] γ: Temperature influence factor, with a dimension of 1 / °C, calibrated through the following experiment: Under the constant pressure condition (P = 101.325 kPa), change the temperature T and measure the capacitance change ΔC; Use the linear regression method to fit the relationship curve between ΔC / C_ref and (T - T_ref), and the slope is γ (the measured γ = 0.0002 / °C).

[0065] T: The medium temperature measured in real time by the temperature sensor probe 36, in °C.

[0066] T_ref: Reference temperature, usually taking the standard condition T_ref = 25°C (corresponding to P_ref = 101.325 kPa in the pressure correction).

[0067] Function and effect: Reduce the micro water measurement error caused by pressure fluctuation from ±3% to ±0.5%, and the temperature-pressure cross-interference suppression ratio ≥ 40 dB.

[0068] (3)Time diversity peak staggering control The sampling time sequence of each sensor is controlled by a pseudo-random sequence: A 32-bit linear feedback shift register (LFSR) is used to generate a pseudo-random code, and the generating polynomial is x 32 +x 22 +x 2 +x + 1; The density sensor probe 34 triggers sampling at the rising edge of the system clock, and the micro-water sensor probe 35 samples after a delay (pseudo-random code value × 0.1 ms); The temperature sensor probe 36 and the pressure sensor probe 37 adopt an alternating sampling mode, and the alternating interval is (pseudo-random code value mod 10) × 0.05 ms; Function and effect: Reduce the electromagnetic crosstalk caused by multi-sensor synchronous sampling by 18 dB, and reduce the peak current fluctuation from ±20 mA to ±5 mA.

[0069] 2. Specific implementation of the adaptive frequency hopping mechanism in step S4 Frequency band switching control process of the wireless communication module 40: (1) Electromagnetic interference detection: Adopt the RSSI (Received Signal Strength Indication) energy detection method and scan step by step at 1 MHz within the 2.400 - 2.4835 GHz frequency band; The interference determination threshold is set to -85 dBm, and when the RSSI value of a certain channel continuously exceeds the threshold for 5 seconds, it is marked as an interfered channel.

[0070] (2) Frequency hopping sequence generation: Generate a frequency hopping pattern based on the FHSS (Frequency Hopping Spread Spectrum) technology, and the frequency hopping interval is 2 MHz; The depth of the frequency hopping table is 50 channels, and the frequency hopping rate is 500 hop / s; Use the adaptive frequency hopping algorithm (AFH) in the Bluetooth v5.2 standard to dynamically exclude interfered channels.

[0071] (3) Channel switching execution: When the electromagnetic interference inside the metal shielding layer 60 is detected to exceed the limit, the RF transceiver of the wireless communication module 40 switches to 16 preset standby channels; The TCP connection is maintained during the switching process, and the selective repeat ARQ protocol is used for data packet retransmission, and the window size is set to 8; Function and effect: In the ISM frequency band with an interference intensity of -70 dBm, the bit error rate is reduced from 10 -2 to 10 -6 , the data transmission interruption time ≤ 5 ms, and the channel utilization rate is increased to 92%.

[0072] In this preferred embodiment, the temperature compensation accuracy is improved by four times through the cubic spline interpolation method, the cross-interference error is reduced by 83% by the linear regression pressure correction model, and the electromagnetic compatibility margin is increased by 15 dB by the pseudo-random time sequence control. The adaptive frequency hopping mechanism achieves a packet integrity transmission rate of 99.7% in an environment with 20 Wi-Fi interference sources, meeting the requirements of the industrial field EMC level 4 standard.

[0073] Other embodiments of the present application will be readily apparent to those skilled in the art after considering the specification and practice of the invention disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include known common knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and embodiments are only exemplary, and the true scope and spirit of the present application are pointed out by the following claims.

[0074] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A multi-parameter density micro-water sensor, comprising a housing (10), a power supply module (20), a sensor module (30) and a wireless communication module (40), characterized in that: The housing (10) comprises a top shell (11) and a bottom shell (12), wherein a vertically layered installation cavity is formed between the top shell (11) and the bottom shell (12), and the bottom shell (12) is embedded in a pipeline of a medium to be measured and is in direct contact with the medium to be measured; The installation cavity comprises from top to bottom: The top layer (101) is provided with the power supply module (20), the power supply module (20) comprises a solar panel (21) and a storage battery (22), and the solar panel (21) is embedded in the outer surface of the top shell (11); An intermediate layer (102) is provided with the wireless communication module (40), and a metal shielding layer (60) is provided between the intermediate layer (102) and the top layer (101); The bottom layer (103) is provided with the sensor module (30) and a plurality of independent chambers (31); the sensor module (30) comprises a density sensor probe (34), a micro-water sensor probe (35), a temperature sensor probe (36) and a pressure sensor probe (37); the density sensor probe (34), the micro-water sensor probe (35), the temperature sensor probe (36) and the pressure sensor probe (37) are respectively arranged in the independent chambers (31); the inner walls of the independent chambers (31) are covered with a conductive material coating (32) and are separated by insulating partitions (33); The density sensor probe (34) has a conical probe structure penetrating the bottom shell (12), and the conical probe structure extends into the medium to be measured in the pipeline; The sensing surface of the micro-water sensor probe (35) contacts the medium to be measured through the air-permeable micropores (121) of the bottom shell (12); The temperature sensor probe (36) is connected to the inner wall of the bottom shell (12) via thermally conductive silica gel (361); The pressure sensor probe (37) is a corrugated diaphragm structure embedded in the outer surface of the bottom shell (12); The storage battery (22) is electrically connected to the wireless communication module (40) and the sensor module (30) respectively, and the wireless communication module (40) is signal-connected to the sensor module (30).

2. The sensor according to claim 1, characterized in that: A hydrophobic breathable membrane (122) is provided in the breathable micropores (121), and the contact angle of the hydrophobic breathable membrane (122) is greater than 150°.

3. The sensor according to claim 1, characterized in that: The inner side of the corrugated diaphragm structure is connected to the corresponding independent chamber (31) via a pressure-conducting tube (371); the inner diameter of the pressure-conducting tube (371) is 0.5-1.0 mm.

4. The sensor according to claim 1, characterized in that: An aerogel heat insulation layer is provided between the heat-conducting silica gel (361) and the inner wall of the bottom shell (12).

5. The sensor according to claim 1, characterized in that: The metal shielding layer (60) is made of copper-nickel alloy and has a thickness of 0.5-1.2 mm, and the metal shielding layer (60) is bonded to the PCB substrate of the wireless communication module (40) by means of conductive adhesive.

6. A measurement method based on the multi-parameter density micro-water sensor according to claim 1, characterized in that: The following steps are involved: S1. The solar panel (21) on the outer surface of the top shell (11) collects light energy and converts it into electrical energy, and stores it in the battery (22) to form a dual-mode power supply; S2. Start the sensor module (30) and perform multi-parameter synchronous measurement through the sensor probes disposed in the independent chamber (31): S21. Using a density sensor probe (34) having a conical probe structure to penetrate the bottom shell (12) to measure the density of the medium to be measured; S22. The water sensor probe (35) contacts the water molecules of the medium to be measured through the air-permeable micropores (121) of the bottom shell (12); S23. Conducting the temperature of the medium to be measured to the temperature sensor probe (36) through the thermally conductive silica gel (361); S24. The pressure sensor probe (37) senses the pressure change of the medium to be measured through the corrugated diaphragm structure; S3. Processing the signals of each sensor of the bottom layer (103) in a separate chamber independently, implementing conductive shielding through a conductive material coating (32), and implementing physical isolation through an insulating partition (33) to suppress electromagnetic and mechanical coupling interference between sensors; S4. The processed sensing signal is transmitted to the middle layer (102), and after the signal is isolated by the metal shielding layer (60), the wireless communication module (40) performs data encoding and wireless transmission; S5. Real-time monitoring of the battery (22) power level, when insufficient light automatically switches to the battery (22) power supply mode to maintain continuous operation.

7. The measuring method according to claim 6, characterized in that: The independent processing of the sub-chambers in step S3 includes: Performing temperature compensation calibration on the impedance signal of the density sensor probe (34); Performing medium pressure correlation correction on the capacitance value of the micro-water sensor probe (35); The time diversity method is used to stagger the sampling timing of each sensor.

8. The measuring method according to claim 6, characterized in that: The wireless transmission in step S4 adopts an adaptive frequency hopping mechanism, and when it is detected that the electromagnetic interference in the metal shielding layer (60) exceeds a threshold, the communication frequency band is automatically switched.

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