Water conservancy foundation pit water level monitoring device and monitoring method

Abstract

This invention relates to the field of construction engineering technology, and in particular to a water level monitoring device and method for hydraulic foundation pits. The water level monitoring device for hydraulic foundation pits of this invention includes a monitoring tube, a multi-stage filtration assembly, a self-cleaning assembly, an insulating base tube, a capacitive sensing assembly, and a cleaning float ring. The lower wall of the monitoring tube has several seepage holes. The multi-stage filtration assembly is fitted around the lower outer periphery of the monitoring tube and completely covers the seepage holes. The self-cleaning assembly is installed on the monitoring tube to remove sediment adhering to the outer surface of the multi-stage filtration assembly. The insulating base tube is vertically arranged inside the monitoring tube, and its lower wall has a connecting opening, allowing communication between the monitoring tube and the insulating base tube. The cleaning float ring is fitted around the outer wall of the insulating base tube and can slide freely along its axial direction. A sealing interlayer is formed between the outer and inner walls of the insulating base tube, and the capacitive sensing assembly is located within the sealing interlayer.

Description

Technical Field

[0001] This invention relates to the field of building engineering technology, and in particular to a water level monitoring device and method for hydraulic foundation pits. Background Technology

[0002] During the construction of water conservancy projects, the excavation of foundation pits often requires penetrating underground aquifers. The continuous seepage of groundwater into the pit not only worsens construction conditions but can also lead to serious safety accidents such as a decrease in the bearing capacity of the foundation, slope instability, and even pit collapse. Therefore, real-time and accurate monitoring of the water level in the foundation pit is a crucial step in ensuring the safety of water conservancy project construction.

[0003] Currently, various technical solutions have been developed in the field of foundation pit water level monitoring. Traditional float-type water level monitoring devices utilize a buoy that moves a floating rod as the water level rises and falls, with a contact switch providing early warning. This solution is simple in structure, but the contacts of the contact switch are prone to oxidation and decreased sensitivity after long-term use. Furthermore, the float is easily jammed in foundation pit water containing silt, making continuous and accurate water level measurement impossible. Capacitive water level monitoring solutions use electrodes on the inner wall of an insulating tube to form a capacitor structure, detecting the water level by utilizing changes in the dielectric constant caused by water level changes. This offers the advantage of non-contact measurement, but the unstable dielectric constant of the measured liquid can cause measurement errors. Moreover, the groundwater in foundation pits is rich in silt and salt, and long-term accumulation of dirt on the electrode surface significantly affects the accuracy of capacitance measurement, requiring frequent manual disassembly and cleaning. In addition, resistive water level monitoring solutions use high-resistance wires and conductor floats to form a variable resistance circuit. However, when the high-resistance wires are immersed in silty groundwater for extended periods, conductive impurities easily adhere to the wire surface, causing resistance drift. The conductor float also experiences increased sliding resistance in silty environments, resulting in a delayed response. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a water level monitoring device and method for hydraulic foundation pits. The water level monitoring device can effectively cope with the complex silt environment of the foundation pit, has the ability to self-clean without power, the electrode plates are permanently isolated from the water being measured, and the data reliability is improved by dual-channel redundant measurement. At the same time, it has a long maintenance-free cycle.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: In a first aspect, the present invention provides a water level monitoring device for a hydraulic foundation pit, comprising a monitoring tube, a multi-stage filtration assembly, a self-cleaning assembly, an insulating base tube, a capacitive sensing assembly, and a cleaning float ring; the lower wall of the monitoring tube has several seepage holes; the multi-stage filtration assembly is sleeved on the lower outer periphery of the monitoring tube and completely covers the seepage holes; the self-cleaning assembly is installed on the monitoring tube to remove sediment adhering to the outer surface of the multi-stage filtration assembly; the insulating base tube is vertically arranged inside the monitoring tube; the lower wall of the insulating base tube has a connecting opening to allow communication between the monitoring tube and the insulating base tube. A cleaning float ring is fitted onto the outer wall of an insulating base tube and can slide freely along its axial direction. A sealing interlayer is formed between the outer wall and the inner wall of the insulating base tube. The capacitive sensing component is disposed within the sealing interlayer. The capacitive sensing component includes a first electrode plate, a second electrode plate, and a reference electrode plate. The first electrode plate, the second electrode plate, and the reference electrode plate are all sealed within the sealing interlayer and extend axially. The reference electrode plate is located at the bottom. The first electrode plate and the reference electrode plate constitute a first measuring capacitance, and the second electrode plate and the reference electrode plate constitute a second measuring capacitance. It also includes a signal processing and transmission module, which is electrically connected to the first electrode plate, the second electrode plate and the reference electrode plate, for collecting the capacitance values ​​of the first measuring capacitor and the second measuring capacitor, fusing the two capacitance values ​​to obtain water level data, and transmitting the water level data outward.

[0006] Furthermore, the self-cleaning component includes an annular scraper sleeved around the periphery of the monitoring tube, an annular float fixed to the annular scraper, and a guide rod extending along the axial direction of the monitoring tube. The annular float moves the annular scraper back and forth along the guide rod as the water level in the pit rises and falls.

[0007] Furthermore, the annular scraper is provided with elastic bristles on its inner periphery, and the ends of the elastic bristles flexibly contact the outermost surface of the multi-stage filter assembly to remove the attached substances. A safety gap is provided between the annular scraper and the outermost surface of the multi-stage filter assembly.

[0008] Furthermore, there are two guide rods, which are symmetrically arranged on both sides of the monitoring tube. The upper and lower ends of each guide rod are fixedly connected to the tube wall of the monitoring tube through connectors. The annular float and the annular scraper are provided with guide holes symmetrically arranged on both sides of the monitoring tube corresponding to the guide rods. The guide holes are slidably engaged with the guide rods.

[0009] Furthermore, the multi-stage filtration assembly includes a first-stage coarse filter layer, a second-stage medium filter layer, and a third-stage fine filter layer. The first-stage coarse filter layer is a stainless steel perforated mesh, the second-stage medium filter layer is a stainless steel woven mesh, and the third-stage fine filter layer is a non-woven filter layer. The pore size of each filter layer decreases sequentially.

[0010] Furthermore, the inner circumferential surface of the cleaning float ring is provided with a plurality of centripetally protruding positioning bosses and cleaning scrapers at intervals along the circumferential direction. A sliding gap is provided between the top surface of the positioning bosses and the outer surface of the outer tube wall of the insulating base tube, so that the cleaning float ring remains coaxial with the insulating base tube. The cleaning scraper extends radially out of the top surface of the positioning bosses in the free state, and the cleaning scraper forms an elastic interference contact with the outer surface of the outer tube wall of the insulating base tube.

[0011] Furthermore, the cleaning scraper includes a segmented lip made of elastic polymer material and an elastic support. The inner side of the segmented lip is connected to the cleaning float ring through the elastic support, so that each segmented lip can independently retract radially when it encounters a hard obstacle.

[0012] Furthermore, the signal processing and transmission module includes a capacitance detection chip, a microprocessor, a wireless communication unit, and a power supply unit; the capacitance detection chip is used to synchronously acquire the capacitance values ​​of the first and second measuring capacitors and convert them into digital signals; the microprocessor is used to fuse the two capacitance values ​​and determine the water level data based on the fusion result; the wireless communication unit is used to send the water level data to the remote monitoring platform; and the power supply unit is used to supply power to the capacitance detection chip, the microprocessor, and the wireless communication unit.

[0013] Furthermore, the microprocessor is also configured to: determine that the sensor is abnormal and send a maintenance alarm signal when the difference between the water level values ​​corresponding to the first measuring capacitor and the second measuring capacitor exceeds a preset threshold.

[0014] Secondly, the present invention also provides a method for monitoring the water level of a hydraulic foundation pit based on the monitoring equipment described in the first aspect, which includes the following steps: S1: Excitation application: The signal processing and transmission module applies an AC excitation voltage to the reference electrode sheet, causing the first and second measuring capacitors to generate response signals. S2: Signal acquisition, the signal processing and transmission module synchronously acquires the response signals on the first electrode plate and the second electrode plate, and after demodulation, obtains capacitance values ​​C1 and C2 that are proportional to the first measuring capacitor and the second measuring capacitor, respectively; S3: Fusion processing: The signal processing and transmission module compares C1 and C2. When the difference between the two is within a preset threshold, the two are fused to obtain a fused capacitance value. When the difference between the two exceeds the preset threshold, the sensor is determined to be abnormal and a maintenance alarm signal is sent out. S4: Water level conversion, the signal processing and transmission module converts the fused capacitance value into the current water level height in the monitoring tube according to the pre-calibrated capacitance-water level correspondence function; S5: Data output, the signal processing and transmission module transmits the current water level height to the outside to complete water level monitoring.

[0015] The beneficial effects of this invention are: 1. This invention fixes an annular float to an annular scraper, utilizing the energy of natural fluctuations in the pit's water level to drive the scraper's reciprocating motion along a guide rod. The elastic bristles on the inner periphery of the annular scraper continuously remove sediment from the outer surface of the multi-stage filtration components, preventing clogging of the seepage holes. This natural energy of water level fluctuations is converted into self-cleaning power, requiring no external electrical drive and eliminating the inherent reliability issues of electric cleaning solutions, such as motor waterproofing failures and sediment jamming of transmission components. The more frequent the water level fluctuations, the more cleaning cycles are performed, forming an adaptive cleaning mechanism.

[0016] 2. The multi-stage filtration assembly of this invention consists of a nested first-stage coarse filter layer, a second-stage medium filter layer, and a third-stage fine filter layer, with the pore size of each filter layer decreasing sequentially. Before entering the monitoring pipe, groundwater must pass through the three filter layers in sequence, where large, medium, and fine particles of sediment are intercepted at each stage. This reduces pollutants entering the pipe at the source, providing a clean water environment for the long-term stable operation of the capacitive sensor.

[0017] 3. This invention designs the insulating base tube as a double-layer coaxial sealed structure, forming a sealed interlayer between the outer and inner tube walls. The first electrode plate, the second electrode plate, and the reference electrode plate are all sealed within this interlayer. The electrode plates are isolated from the water being measured through the insulating inner tube wall. Electric field lines penetrate the inner tube wall to sense changes in the water level within the hollow cavity, while the electrode plates themselves never come into contact with the water being measured. This structure completely eliminates electrode corrosion, scale adhesion, and electrochemical interference, ensuring the long-term stability of the sensing element from a physical perspective, eliminating the need for disassembly, cleaning, or electrode replacement.

[0018] 4. This invention employs two sets of measuring electrodes, a first electrode plate and a second electrode plate, each forming an independent measuring capacitor with a reference electrode plate. Both capacitance values ​​change with the water level, and the signal processing module fuses the two signals, averaging them. This effectively suppresses random noise and localized accidental interference, improving the stability of the measurement data. The capacitive sensor senses the water level by penetrating the inner wall of the insulated base tube through an electric field; the measurement process does not depend on optical transparency or the conductivity of water. Even if the groundwater in the pit is turbid, contains suspended solids, or has foam on the surface, the capacitance measurement remains stable and reliable. Compared to infrared or laser ranging schemes, which are prone to failure in turbid water, this invention exhibits significantly greater adaptability to water quality. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the multi-stage filtration assembly of the present invention; Figure 3 This is a schematic diagram of the structure of the annular scraper of the present invention; Figure 4 This is a schematic diagram of the structure of the insulating base tube of the present invention; Figure 5 This is a schematic diagram of the electrode sheet of the present invention; Figure 6 This is a schematic diagram of the cleaning floating ring of the present invention.

[0020] Explanation of reference numerals in the attached drawings: 1-Monitoring tube, 11-Water seepage hole, 2-Multi-stage filtration assembly, 21-First stage coarse filter layer, 22-Second stage medium filter layer, 23-Third stage fine filter layer, 3-Self-cleaning assembly, 31-Annular scraper, 311-Elastic bristles, 32-Annular float, 33-Guide rod, 331-Connector, 4-Insulating base tube, 41-Connecting opening, 5-Cleaning float ring, 51-Positioning boss, 52-Cleaning scraper, 521-Split lip, 522-Elastic support, 6-First electrode plate, 7-Second electrode plate, 8-Reference electrode plate. Detailed Implementation

[0021] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0022] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also mean including the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0023] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0024] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. The meaning of such spatial relative terms includes different orientations of the device in use or operation, in addition to the orientation depicted in the figure. For example, if the device in the figure is flipped, then an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly. Example 1

[0025] like Figure 1-6As shown, the present invention provides a water level monitoring device for a hydraulic foundation pit, comprising a monitoring pipe 1, a multi-stage filtration assembly 2, a self-cleaning assembly 3, an insulating base pipe 4, a capacitive sensing assembly, and a cleaning float ring 5. The lower wall of the monitoring pipe 1 has several seepage holes 11. The multi-stage filtration assembly 2 is sleeved on the lower outer periphery of the monitoring pipe 1 and completely covers the seepage holes 11. The self-cleaning assembly 3 is installed on the monitoring pipe 1 to remove sediment adhering to the outer surface of the multi-stage filtration assembly 2. The insulating base pipe 4 is vertically arranged inside the monitoring pipe 1, and a connecting opening 41 is provided in the lower wall of the insulating base pipe 4 to connect the monitoring pipe 1 and the insulating base pipe 4. The cleaning float ring 5 is sleeved on the outer wall of the insulating base pipe 4 and can slide freely along its axial direction. The outer wall and inner wall of the insulating base pipe 4 are connected... A sealed interlayer is formed, and the capacitive sensing component is disposed within the sealed interlayer. The capacitive sensing component includes a first electrode plate 6, a second electrode plate 7, and a reference electrode plate 8. The first electrode plate 6, the second electrode plate 7, and the reference electrode plate 8 are all sealed within the sealed interlayer and extend axially. The reference electrode plate 8 is located at the bottom. The first electrode plate 6 and the reference electrode plate 8 constitute a first measuring capacitor, and the second electrode plate 7 and the reference electrode plate 8 constitute a second measuring capacitor. The system also includes a signal processing and transmission module, which is electrically connected to the first electrode plate 6, the second electrode plate 7, and the reference electrode plate 8. This module is used to acquire the capacitance values ​​of the first and second measuring capacitors, fuse the two capacitance values ​​to obtain water level data, and transmit the water level data outward.

[0026] In actual use, the lower wall of the monitoring tube 1 has seepage holes 11. A multi-stage filtration assembly 2 is fitted around its periphery and completely covers the seepage holes 11. Groundwater must pass through multiple stages of filtration before entering the monitoring tube 1 to intercept sediment and suspended solids at the source. The insulating base tube 4 is vertically installed inside the monitoring tube 1, with a connecting opening 41 at its lower part to form a communicating vessel between the two, ensuring that the water level inside the insulating base tube 4 is synchronized with the water level inside the monitoring tube 1. The insulating base tube 4 adopts a double-layer coaxial sealing structure composed of an outer tube wall and an inner tube wall. The first electrode plate 6, the second electrode plate 7, and the reference electrode plate 8 of the capacitive sensing assembly are all sealed in this sealing interlayer and extend axially. The electrode plates are permanently isolated from the water being measured through the inner tube wall. The electric field lines penetrate the inner tube wall to sense the change in the dielectric constant of the medium in the hollow inner cavity. The electrode plates themselves never come into contact with the water being measured, fundamentally eliminating electrode corrosion, scale adhesion, and electrochemical interference. The first electrode plate 6 and the second electrode plate 7, together with the reference electrode plate 8, constitute the first measuring capacitor and the second measuring capacitor, respectively. The signal processing and transmission module synchronously acquires the two capacitance values ​​and performs fusion processing. The dual-channel redundancy design effectively suppresses random noise and local accidental interference, improving the stability and reliability of the measurement data.

[0027] In a preferred embodiment of this invention, the self-cleaning component 3 includes an annular scraper 31 fitted around the outer periphery of the monitoring pipe 1, an annular float 32 fixed to the annular scraper 31, and a guide rod 33 extending axially along the monitoring pipe 1. The annular float 32, as the water level in the pit rises and falls, drives the annular scraper 31 to reciprocate along the guide rod 33. In actual use, the annular scraper 31 is fitted around the outer periphery of the monitoring pipe 1, the annular float 32 is fixed to the annular scraper 31, and the guide rod 33 extends axially along the monitoring pipe 1. When the groundwater level in the pit rises and falls, the annular float 32 is driven up and down by buoyancy, driving the annular scraper 31 to reciprocate along the guide rod 33, continuously removing sediment from the outer surface of the multi-stage filtration component 2. This structure converts the energy of natural water level fluctuations into self-cleaning driving force, requiring no external power supply, eliminating the risk of motor waterproofing failure or sediment jamming in transmission components, and achieving maintenance-free operation.

[0028] In a preferred embodiment of this invention, the annular scraper 31 is provided with elastic bristles 311 on its inner periphery. The ends of the elastic bristles 311 flexibly contact the outermost surface of the multi-stage filter assembly 2 to remove adhering substances. A safety gap is provided between the annular scraper 31 and the outermost surface of the multi-stage filter assembly 2. In actual use, the elastic bristles 311 on the inner periphery of the annular scraper 31, with their ends flexibly contacting the outermost surface of the multi-stage filter assembly 2, remove adhering substances during reciprocating motion, preventing blockage of the seepage holes 11. The safety gap between the annular scraper 31 and the outermost surface of the multi-stage filter assembly 2 prevents the rigid parts other than the elastic bristles 311 from scratching the filter layer, and also avoids jamming or filter damage caused by rigid scraping teeth getting stuck in the filter mesh holes.

[0029] In a preferred embodiment of this invention, there are two guide rods 33, symmetrically arranged on both sides of the monitoring tube 1. The upper and lower ends of each guide rod 33 are fixedly connected to the wall of the monitoring tube 1 via connectors 331. The annular float 32 and the annular scraper 31 each have guide holes symmetrically arranged on both sides of the monitoring tube 1 corresponding to the guide rods 33, and these guide holes slide in cooperation with the guide rods 33. In actual use, the two guide rods 33 are symmetrically arranged on both sides of the monitoring tube 1, with their upper and lower ends fixedly connected to the wall of the monitoring tube 1 via connectors 331. The annular float 32 and the annular scraper 31 have guide holes corresponding to the guide rods 33 and slide in cooperation with them. This symmetrical guiding structure constrains the movement trajectory of the annular float 32 and the annular scraper 31, preventing skewing or twisting during vertical movement, ensuring uniform contact between the elastic bristles 311 and the outer surface of the filter layer, resulting in consistent cleaning performance. It also makes the movement smoother and more stable, reducing the risk of jamming.

[0030] In a preferred embodiment of this invention, the multi-stage filtration assembly 2 includes a first-stage coarse filter layer 21, a second-stage medium filter layer 22, and a third-stage fine filter layer 23. The first-stage coarse filter layer 21 is a stainless steel perforated mesh, the second-stage medium filter layer 22 is a stainless steel woven mesh, and the third-stage fine filter layer 23 is a non-woven filter layer. The pore size of each filter layer decreases sequentially. In actual use, the first-stage coarse filter layer 21, made of stainless steel perforated mesh, intercepts large particles of silt; the second-stage medium filter layer 22, made of stainless steel woven mesh, intercepts medium-sized particles; and the third-stage fine filter layer 23, made of non-woven fabric, intercepts fine particles. The sequentially decreasing pore size of each filter layer forms a gradient interception, preventing a single filter layer from being clogged by silt of a certain particle size range. Each filter layer uses three different materials and structures—perforated mesh, woven mesh, and non-woven fabric—each taking advantage of its strengths in impact resistance, filtration accuracy, and service life. The overall filtration efficiency and durability are superior to single-layer or multi-layer filtration schemes made of the same material.

[0031] In a preferred embodiment of this invention, the inner circumferential surface of the cleaning float ring 5 is provided with a plurality of centripetally protruding positioning bosses 51 and cleaning scrapers 52 spaced apart along the circumferential direction. A sliding gap is provided between the top surface of the positioning bosses 51 and the outer surface of the outer tube wall of the insulating base tube 4, so that the cleaning float ring 5 remains coaxial with the insulating base tube 4. The cleaning scrapers 52 extend radially out of the top surface of the positioning bosses 51 in the free state, and the cleaning scrapers 52 form an elastic interference contact with the outer surface of the outer tube wall of the insulating base tube 4. In actual use, the inner circumferential surface of the cleaning float ring 5 is provided with centripetally protruding positioning bosses 51 and cleaning scrapers 52 spaced apart along the circumferential direction. A sliding gap is left between the top surface of the positioning bosses 51 and the outer surface of the outer tube wall of the insulating base tube 4, so that the cleaning float ring 5 always remains coaxial with the insulating base tube 4 during the up and down movement, without eccentricity or tilting, and the movement is smooth and stable. In its free state, the cleaning scraper 52 extends radially outward from the top surface of the positioning boss 51, forming an elastic interference contact with the outer surface of the outer wall of the insulating base tube 4. This ensures that the cleaning scraper 52 is always in close contact with the tube wall, effectively removing any scale or deposits that may adhere to the tube wall surface. The positioning boss 51 and the cleaning scraper 52 are arranged at intervals, achieving separation of the guiding and cleaning functions. The positioning boss 51 is responsible for ensuring coaxiality and movement clearance, while the cleaning scraper 52 is responsible for removing deposits. They work independently without interfering with each other.

[0032] In a preferred embodiment of this invention, the cleaning scraper 52 includes a segmented lip 521 made of elastic polymer material and an elastic support 522. The inner side of the segmented lip 521 is connected to the cleaning float ring 5 via the elastic support 522, allowing each segmented lip 521 to independently retract radially when encountering a hard obstacle. In actual use, the cleaning scraper 52 consists of a segmented lip 521 made of elastic polymer material and an elastic support 522, with the inner side of the segmented lip 521 connected to the cleaning float ring 5 via the elastic support 522. The elastic polymer material itself has self-lubricating properties, resulting in low sliding friction resistance between it and the outer wall of the insulating base tube 4, and will not damage the tube wall surface during long-term operation. When the segmented lip 521 encounters hard particles or local protrusions attached to the tube wall surface during movement, the segment can be compressed by the obstacle and independently retract radially. After overcoming the obstacle, it reattaches to the tube wall under the restoring force of the elastic support 522. Each petal works independently, and the retraction of a single petal does not affect the continued adhesion of other petals to the tube wall. This ensures the cleaning effect while avoiding the problem of the entire cleaning floating ring 5 getting stuck due to local obstacles, thus improving the fault tolerance and operational reliability of the cleaning structure.

[0033] In a preferred embodiment of this invention, the signal processing and transmission module includes a capacitance detection chip, a microprocessor, a wireless communication unit, and a power supply unit. The capacitance detection chip is used to simultaneously acquire the capacitance values ​​of a first measuring capacitor and a second measuring capacitor and convert them into digital signals. The microprocessor is used to fuse the two capacitance values ​​and determine the water level data based on the fusion result. The wireless communication unit is used to send the water level data to a remote monitoring platform. The power supply unit is used to power the capacitance detection chip, the microprocessor, and the wireless communication unit. In actual use, the capacitance detection chip is used to simultaneously acquire the capacitance values ​​of the first measuring capacitor and the second measuring capacitor and convert them into digital signals. The microprocessor fuses the two capacitance values ​​and determines the water level data. The communication unit sends the water level data outward, and the power supply unit powers all the aforementioned units. This structure integrates capacitance signal acquisition, data processing, water level conversion, and remote transmission into one unit, realizing a complete functional chain from front-end measurement to back-end output. The modular design facilitates maintenance, replacement, and functional upgrades.

[0034] In a preferred embodiment of this invention, the microprocessor is further configured to: determine a sensor malfunction and send a maintenance alarm signal when the difference between the water level values ​​corresponding to the first and second measuring capacitors exceeds a preset threshold. In actual use, the microprocessor compares the water level values ​​corresponding to the first and second measuring capacitors in real time; when the difference exceeds the preset threshold, it determines a sensor malfunction and sends a maintenance alarm signal. This function enables the device to have self-monitoring capabilities, allowing for timely alarms when faults such as single-channel electrode damage, lead wire breakage, or local insulation failure occur, avoiding silent failures caused by inaccurate water level data due to single-channel sensor malfunctions that go unnoticed by maintenance personnel. Example 2

[0035] like Figure 1-6 As shown, based on Embodiment 1, this embodiment provides a method for monitoring the water level of a hydraulic foundation pit using the monitoring equipment described in Embodiment 1, which includes the following steps: S1: Excitation application: The signal processing and transmission module applies an AC excitation voltage to the reference electrode plate 8, causing the first and second measuring capacitors to generate response signals. S2: Signal acquisition, the signal processing and transmission module synchronously acquires the response signals on the first electrode plate 6 and the second electrode plate 7, and after demodulation, obtains capacitance values ​​C1 and C2 that are proportional to the first measuring capacitor and the second measuring capacitor, respectively. S3: Fusion processing: The signal processing and transmission module compares C1 and C2. When the difference between the two is within a preset threshold, the two are fused to obtain a fused capacitance value. When the difference between the two exceeds the preset threshold, the sensor is determined to be abnormal and a maintenance alarm signal is sent out. S4: Water level conversion, the signal processing and transmission module converts the fused capacitance value into the current water level height in the monitoring tube according to the pre-calibrated capacitance-water level correspondence function; S5: Data output, the signal processing and transmission module transmits the current water level height to the outside to complete water level monitoring.

[0036] In practical use, the capacitive sensing assembly includes a first electrode plate 6, a second electrode plate 7, and a reference electrode plate 8. All three are sealed within the sealed interlayer of the insulating base tube 4, extending axially without contacting each other, with the reference electrode plate 8 located at the bottom. The reference electrode plate 8 and the first electrode plate 6 constitute the first measuring capacitor C1, and the reference electrode plate 8 and the second electrode plate 7 constitute the second measuring capacitor C2.

[0037] According to the basic physical formula for capacitance: C = ε·d / A Where A is the effective area of ​​the electrode, d is the equivalent distance between the electrodes, and ε is the equivalent dielectric constant of the medium between the electrodes. In this device, the geometric dimensions (A, d) of the electrodes are fixed after being determined by the manufacturing process, and the change in capacitance C depends only on the change in the equivalent dielectric constant ε.

[0038] Electric field lines emanate from the electrode plates, penetrate the inner wall of the insulating base tube 4, and enter the hollow cavity. The medium in the hollow cavity is a mixture of water and air. The relative permittivity of water is approximately 80, while that of air is approximately 1, a difference of nearly 80 times. When the water level in the insulating base tube 4 changes, the water-to-air ratio in the hollow cavity changes accordingly: when the water level rises, the high-dielectric-constant water replaces the low-dielectric-constant air, increasing the equivalent permittivity between the electrodes and thus increasing the measured capacitance; when the water level falls, air replaces the water, decreasing the equivalent permittivity and thus decreasing the measured capacitance. The capacitance value and the water level height in the insulating base tube 4 exhibit a monotonic, approximately linear correspondence. Through pre-calibration, a mapping table or fitting function between capacitance value and water level height can be established, thereby enabling the conversion from capacitance value to water level height.

[0039] The signal processing and transmission module applies an AC excitation voltage V with a fixed frequency and amplitude to the reference electrode plate. ex In an AC circuit, the capacitive reactance of a capacitor is: X C =2πfC / 1 Where f is the excitation frequency, C is the capacitance value, and V is the excitation voltage. ex The first measuring capacitor C1 is coupled to the first electrode plate, generating an alternating current signal I1 = 2πf·C1·V. ex Simultaneously, the signal is coupled to the second electrode plate through the second measuring capacitor C2, generating an alternating current signal I2 = 2πf·C2·V. ex .

[0040] The capacitance detection chip inside the signal processing and transmission module has two independent detection input channels, connected to the first electrode plate and the second electrode plate respectively. The two channels synchronously acquire the AC response signals they receive, amplify and demodulate them, and convert them into digital capacitance values ​​proportional to C1 and C2 respectively, which are then output to the microprocessor for further processing.

[0041] All technical features in this embodiment can be freely combined according to actual needs. The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

[0042] The above embodiments are preferred implementations of the present invention. In addition, other implementations are also included. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A water conservancy foundation pit water level monitoring device, characterized in that: The system includes a monitoring tube (1), a multi-stage filtration assembly (2), a self-cleaning assembly (3), an insulating base tube (4), a capacitive sensing assembly, and a cleaning float (5). The lower wall of the monitoring tube (1) has several seepage holes (11). The multi-stage filtration assembly (2) is fitted around the lower outer periphery of the monitoring tube (1) and completely covers the seepage holes (11). The self-cleaning assembly (3) is installed on the monitoring tube (1) to remove deposits adhering to the outer surface of the multi-stage filtration assembly (2). The insulating base tube (4) is vertically positioned inside the monitoring tube (1). The lower wall of the insulating base tube (4) has a connecting opening (41) to connect the monitoring tube (1) and the insulating base tube (4). The cleaning float... The ring (5) is sleeved on the outer wall of the insulating base tube (4) and can slide freely along its axial direction. A sealing interlayer is formed between the outer wall and the inner wall of the insulating base tube (4). The capacitive sensing component is disposed in the sealing interlayer. The capacitive sensing component includes a first electrode plate (6), a second electrode plate (7), and a reference electrode plate (8). The first electrode plate (6), the second electrode plate (7), and the reference electrode plate (8) are all sealed in the sealing interlayer and extend along the axial direction. The reference electrode plate (8) is located at the bottom. The first electrode plate (6) and the reference electrode plate (8) constitute a first measuring capacitor. The second electrode plate (7) and the reference electrode plate (8) constitute a second measuring capacitor. It also includes a signal processing and transmission module, which is electrically connected to the first electrode plate (6), the second electrode plate (7) and the reference electrode plate (8), for collecting the capacitance values ​​of the first measuring capacitor and the second measuring capacitor, performing fusion processing on the two capacitance values ​​to obtain water level data, and transmitting the water level data outward.

2. The water conservancy foundation water level monitoring device according to claim 1, characterized in that: The self-cleaning component (3) includes an annular scraper (31) sleeved on the outer periphery of the monitoring tube (1), an annular float (32) fixed on the annular scraper (31), and a guide rod (33) extending along the axial direction of the monitoring tube (1). The annular float (32) drives the annular scraper (31) to reciprocate along the guide rod (33) as the water level in the pit rises and falls.

3. The water level monitoring device for a hydraulic foundation pit according to claim 2, characterized in that: The annular scraper (31) is provided with elastic bristles (311) on its inner periphery. The ends of the elastic bristles (311) are in flexible contact with the outermost surface of the multi-stage filter assembly (2) to remove the attached substances. A safety gap is provided between the annular scraper (31) and the outermost surface of the multi-stage filter assembly (2).

4. The water level monitoring device for a hydraulic foundation pit according to claim 2, characterized in that: There are two guide rods (33), which are symmetrically arranged on both sides of the monitoring tube (1). The upper and lower ends of each guide rod (33) are fixedly connected to the tube wall of the monitoring tube (1) through connectors (331). The annular float (32) and the annular scraper (31) are provided with guide holes symmetrically arranged on both sides of the monitoring tube (1) corresponding to the guide rods (33). The guide holes are slidably engaged with the guide rods (33).

5. The water level monitoring device for a hydraulic foundation pit according to claim 1, characterized in that: The multi-stage filtration assembly (2) includes a first-stage coarse filter layer (21), a second-stage medium filter layer (22), and a third-stage fine filter layer (23). The first-stage coarse filter layer (21) is a stainless steel perforated mesh, the second-stage medium filter layer (22) is a stainless steel woven mesh, and the third-stage fine filter layer (23) is a non-woven filter layer. The filtration pore size of each filter layer decreases sequentially.

6. The water level monitoring device for a hydraulic foundation pit according to claim 1, characterized in that: The inner circumferential surface of the cleaning float (5) is provided with a plurality of centripetally protruding positioning bosses (51) and cleaning scrapers (52) at intervals along the circumferential direction. A sliding gap is provided between the top surface of the positioning bosses (51) and the outer surface of the outer tube wall of the insulating base tube (4) so ​​that the cleaning float (5) remains coaxial with the insulating base tube (4). The cleaning scraper (52) extends radially out of the top surface of the positioning bosses (51) in a free state. The cleaning scraper (52) forms an elastic interference contact with the outer surface of the outer tube wall of the insulating base tube (4).

7. The water level monitoring device for a hydraulic foundation pit according to claim 6, characterized in that: The cleaning scraper (52) includes a split lip (521) and an elastic support (522) made of elastic polymer material. The inner side of the split lip (521) is connected to the cleaning float (5) through the elastic support (522), so that each split lip (521) can retract radially independently when it encounters a hard obstacle.

8. The water level monitoring device for a hydraulic foundation pit according to claim 1, characterized in that: The signal processing and transmission module includes a capacitance detection chip, a microprocessor, a wireless communication unit, and a power supply unit. The capacitance detection chip is used to synchronously acquire the capacitance values ​​of the first and second measuring capacitors and convert them into digital signals. The microprocessor is used to fuse the two capacitance values ​​and determine the water level data based on the fusion result. The wireless communication unit is used to send the water level data to a remote monitoring platform. The power supply unit is used to supply power to the capacitance detection chip, the microprocessor, and the wireless communication unit.

9. The water level monitoring device for a hydraulic foundation pit according to claim 8, characterized in that: The microprocessor is also configured to: determine that the sensor is abnormal and send a maintenance alarm signal when the difference between the water level values ​​corresponding to the first measuring capacitor and the second measuring capacitor exceeds a preset threshold.

10. A method for monitoring the water level of a hydraulic foundation pit based on the monitoring equipment described in any one of claims 1-9, characterized in that, Includes the following steps: S1: Excitation is applied. The signal processing and transmission module applies an AC excitation voltage to the reference electrode sheet (8) to cause the first measuring capacitor and the second measuring capacitor to generate response signals. S2: Signal acquisition, the signal processing and transmission module synchronously acquires the response signals on the first electrode plate (6) and the second electrode plate (7), and after demodulation, obtains the capacitance values ​​C1 and C2 that are proportional to the first measuring capacitor and the second measuring capacitor, respectively; S3: Fusion processing: The signal processing and transmission module compares C1 and C2. When the difference between the two is within a preset threshold, the two are fused to obtain a fused capacitance value. When the difference between the two exceeds the preset threshold, the sensor is determined to be abnormal and a maintenance alarm signal is sent out. S4: Water level conversion, the signal processing and transmission module converts the fusion capacitance value into the current water level height in the monitoring tube (1) according to the pre-calibrated capacitance-water level correspondence function; S5: Data output, the signal processing and transmission module transmits the current water level height to the outside to complete water level monitoring.

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