Water level and sediment level measuring device and measuring method thereof

Abstract

The application discloses a water level and silt level measuring device and a measuring method thereof. The measuring device comprises a mounting side wall, a water level and silt level monitoring rib, a water retaining side wall and an anchoring seat. The mounting side wall, the water level and silt level monitoring rib and the water retaining side wall are anchored on the anchoring seat. The water level and silt level monitoring rib is internally provided with multiple groups of series connected strain sensing units. A measuring cavity area is formed between the mounting side wall and the water retaining side wall. The water level and silt level monitoring rib is centrally arranged in the measuring cavity area. The opening width of the water outflow side of the measuring cavity area is less than the diameter of the water level and silt level monitoring rib. The opening width of the water inflow side of the measuring cavity area is more than 1.5 times of the diameter of the water level and silt level monitoring rib. The application completely avoids unstable and unreliable factors such as environmental restrictions and water impurities in water level and silt level measurement. In industrial liquid level and water level automatic measurement and control, the application can be directly connected with a digital system device, and has the advantages of simple structure, stability and reliability, convenient installation and maintenance and the like.

Description

Technical Field

[0001] This invention relates to a sensor for measuring water level and mud level, specifically a real-time, long-term, accurate water level and mud level sensor for use in sewers, underground pipelines, deep wells, tunnels, etc. Background Technology

[0002] Water level and sediment level sensors are widely used in water plants, sewage treatment plants, urban water supply and drainage systems, reservoirs, rivers, and oceans. In practical applications, the performance of the sensing components of a water level sensor directly determines the accuracy and precision of the collected data.

[0003] Currently, there are many technologies and products used in water level detection both domestically and internationally. They can be summarized as follows: (1) Measurement of the distance between the channel and the water surface. For example, the patent "Adaptive Ultrasonic Liquid Level Meter" (patent number 932031064) uses an ultrasonic sensor instrument installed above the water surface to emit and receive ultrasonic waves, and measures the reflected wavelength and period to determine the distance between the water surface and the instrument, thereby determining the water level. However, this sensing technology requires a certain measurement time and is not real-time, and it cannot effectively distinguish between water level and silt level. (2) Water pressure measurement. For example, the patent "Differential Pressure Meter" (publication number CN86105681A) uses the principle of water pressure to detect the pressure difference between the bottom water pressure and the standard atmospheric pressure. However, in the closed environment of sewers and pipes, the bottom water pressure and the air pressure difference are easily affected by the water flow velocity. When silt accumulates, the bottom water pressure cannot be obtained, resulting in the inability to obtain a water level signal. (3) Float-type water level sensor. For example, the patented "Float-type Water Level Gauge" (publication number CN 86107944A) uses the mechanical up-and-down movement of a float to measure water level. Its disadvantage is that in flowing water, the pressure difference between upstream and downstream causes the float to move irregularly, leading to distorted measurement results. Especially during long-term use, it is prone to clogging and jamming by debris, resulting in uncorrectable cumulative measurement errors. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a real-time accurate measuring device and method that simultaneously satisfies the requirements of water level and mud level.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] This invention first provides a water level and sediment level measuring device, comprising: an installation sidewall, a water level and sediment level monitoring rib, a water-retaining sidewall, and an anchoring base; the installation sidewall, the water level and sediment level monitoring rib, and the water-retaining sidewall are all anchored to the anchoring base, and the water level and sediment level monitoring rib is provided with multiple sets of strain sensing units connected in series inside; a measuring cavity area is formed between the installation sidewall and the water-retaining sidewall, and the water level and sediment level monitoring rib is centrally located in the measuring cavity area, the opening width of the measuring cavity area on the water outflow side is smaller than the diameter of the water level and sediment level monitoring rib, and the opening width of the measuring cavity area on the water inflow side is greater than 1.5 times the diameter of the water level and sediment level monitoring rib.

[0007] The water level and mud level monitoring bar is located in the measurement cavity area between the installation side and the water-retaining side wall; its lower end is connected to the anchor seat; 3-5 or more strain sensing units are embedded inside the water level and mud level monitoring bar, and the strain sensing unit at the lowest position of its lower edge is not lower than the lowest water level or mud level of the object to be measured; the strain sensing units are connected in series, and their output ends are led out from one end of the anchor seat.

[0008] The measuring cavity area has a symmetrical flared design in cross-section, and its gap meets and only meets the vibration deformation requirements of the water level and sediment level monitoring rib. The measuring cavity area is the water inlet section from the water-facing side to the center of the water level and sediment level monitoring rib, and its gap size gradually decreases. The measuring cavity area is the water outlet section from the center of the water level and sediment level monitoring rib to the back water side, and its gap size gradually increases.

[0009] Furthermore, the water level and sediment level monitoring rib is a composite material such as carbon fiber, glass, or basalt with superior flexibility and high durability, and the stiffness of its installation sidewall and water-retaining sidewall is much greater than the stiffness of the water level and sediment level monitoring rib.

[0010] Furthermore, the gauge length and number of strain sensing units of the water level and mud level monitoring rib are determined by the historical water level and mud level height statistics of the object to be measured.

[0011] Furthermore, the gap size of the water inlet section of the measurement cavity on the water-facing side is not less than the minimum size that allows water flow, and not greater than the size of common drifting debris; this gap size may or may not be the same as the gap size of the water outlet section on the back side.

[0012] Furthermore, the mounting sidewall is made of a material suitable for bonding with concrete ditch, and the water-retaining sidewall is made of a material with sufficient smoothness on the surface, and meets the requirement that no floating debris accumulates on the water-facing side.

[0013] Furthermore, in the aforementioned water level and mud level measuring device, water flows into the cavity area through the inflow side and then out through the outflow side, thereby accelerating the water flow and causing the additional stiffness of the water level and mud level monitoring rib to meet the design requirements of the minimum vibration frequency for exciting the water level and mud level monitoring rib.

[0014] The additional stiffness of the water level and mud level monitoring ribs caused by the accelerated water flow in the cavity area can be designed using the following formula:

[0015]

[0016] Where, k ω This indicates the additional stiffness caused by the acceleration of the water flow; C d ρ represents the flow load constant, which is the effect of the water flow on the water level and sediment level monitoring reinforcement under normal conditions in the irrigation canal under test; A represents the cross-sectional area of ​​the water level and sediment level monitoring reinforcement subjected to the water flow; and V represents the water velocity.

[0017] The stiffness of the water level and mud level monitoring ribs can be designed using the following formula:

[0018] k = k0 + k ω

[0019] Where k represents the final stiffness of the water level and sediment level monitoring rib after the water flow accelerates, and k0 represents the initial stiffness of the water level and sediment level monitoring rib. ω This refers to the additional stiffness caused by the acceleration of water flow.

[0020] The natural vibration frequency of the water level and sediment level monitoring rib is calculated from the stiffness of the rib and can be designed using the following formula:

[0021]

[0022] Where f represents the vibration frequency of the water level and mud level monitoring bar, and m represents the mass of the water level and mud level monitoring bar.

[0023] This invention also provides a method for testing water level and sediment level, comprising the following steps:

[0024] Step 1: When the water flows through the inlet section of the measuring cavity, the flow velocity accelerates, causing the water level and mud level monitoring ribs to vibrate and deform.

[0025] Step 2: The strain distribution can be obtained by measuring the strain peak value and position of the strain sensing unit inside the water level and mud level monitoring rib. When the mud level changes after submerging the water level and mud level monitoring rib, the mud level height can be directly obtained by observing the change in the inflection point of the strain distribution.

[0026] Step 3: The modal shapes can be obtained by using the strain time history and spectrum analysis methods of the strain sensing unit inside the water level and sediment level monitoring rib. When the water level height submerged by the water level and sediment level monitoring rib changes, the water level height is obtained by the change in the inflection point position of the modal shapes.

[0027] The mud level height of the water level and mud level monitoring rib can be obtained using the following formula:

[0028]

[0029] Among them, Q 1 i h represents the curvature change corresponding to the i-th strain sensing unit within the water level and mud level monitoring rib when the mud level changes. m Indicates the neutral axis height of the water level and sediment level monitoring reinforcement, ε i ε represents the strain value of the i-th strain sensing unit of the water level and mud level monitoring rib before the mud level changes. * i This represents the strain value of the i-th strain sensing unit of the water level and mud level monitoring rib after the mud level height changes.

[0030] When Q 1 i When the value is not zero, the position of the i-th strain sensing unit corresponds to the current mud level height.

[0031] The water level height of the water level and sediment level monitoring ribs can be obtained using the following formula:

[0032]

[0033] Among them, Q 2 i h represents the curvature change corresponding to the i-th strain sensing unit within the water level and sediment level monitoring rib when the water level changes. m The value represents the neutral axis height of the water level and sediment level monitoring rib, and r represents the modal order. This indicates the modal curvature of the water level or sediment level monitoring ribs before a change in water level or sediment level. This indicates the modal curvature of the water level or mud level monitoring rib after a change in water level or mud level height.

[0034] When Q 2 i When the value is not zero, the position of the i-th strain sensing unit corresponds to the current water level.

[0035] Beneficial effects: Compared with the prior art, the advantages of the present invention are as follows:

[0036] 1) The sensing principle of this invention is based on the precise measurement of minute strain, which is then developed into modal vibration analysis that is sensitive to changes in boundary conditions such as water level or mud level. In principle, the measurement error is small and the system is stable and reliable.

[0037] 2) The sensing device of the present invention has strong anti-interference ability and is not easily affected by environmental conditions such as drifting debris, water temperature, and water flow speed.

[0038] 3) The testing method of the present invention is not limited to water level or mud level measurement. When there are special monitoring needs, the requirements for simultaneous measurement of water level and mud level can be met by designing the sensing element.

[0039] 4) This invention does not require professional technicians to operate and has good versatility, making it especially suitable for projects with large-scale monitoring needs. Attached Figure Description

[0040] Figure 1 This is a front view of the device of the present invention.

[0041] Figure 2 This is a three-dimensional view of the device of the present invention.

[0042] Figure 3 This is an example diagram showing the layout of the device of the present invention.

[0043] Figure 4 This is the strain distribution measurement result of the present invention.

[0044] Figure 5 This is the result of the inflection point location of the strain distribution in this invention.

[0045] Figure 6 These are the measurement results of different mud and water levels according to the present invention.

[0046] Wherein: 1-Installation sidewall; 2-Water level and mud level monitoring rib; 21-Inserted strain sensing unit; 211-Strain sensing unit at the lowest position of the lower edge; 3-Water-retaining sidewall; 4-Anchor seat; 5-Measuring cavity area; 100-Cement level measuring device; 200-Bottom series output port. Detailed Implementation

[0047] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the embodiments described.

[0048] like Figure 1 The cement level measuring device of the present invention, as shown, consists of a water level and mud level monitoring rib 2, an installation side wall 1, a water-retaining side wall 3, and an anchoring seat 4. The lower end of the water level and mud level monitoring rib 2 is connected to the anchoring seat 4; 3-5 or more strain sensing units 21 are embedded inside the water level and mud level monitoring rib 2, and the strain sensing unit at the lowest position of its lower edge is not lower than the lowest water level or mud level of the object to be measured.

[0049] like Figure 2The water level and mud level monitoring rib of the cement level measuring device of the present invention is located in the measuring cavity area 5 between the installation side and the water-retaining sidewall. The gap of the measuring cavity area satisfies, and only satisfies, the vibration deformation requirements of the water level and mud level monitoring rib. Its cross-section is a symmetrical funnel shape, meaning the gap size gradually decreases from the water-facing side to the center of the water level and mud level monitoring rib, and gradually increases from the center of the water level and mud level monitoring rib to the backwater side. The opening width of the measuring cavity area 5 on the water-flow side is more than 1.5 times the diameter of the water level and mud level monitoring rib 2. When the water flows through the measuring cavity area, the flow velocity accelerates, causing the water level and mud level monitoring rib to vibrate, thereby obtaining the strain distribution and mode shape of the water level and mud level monitoring rib.

[0050] like Figure 3 Therefore, the cement level measuring device 100 of the present invention is installed in parallel within the water flow channel to be measured. This water flow channel can be a sewer, underground pipe, deep well, tunnel, etc. Multiple cement level measuring devices 100 output measurement signals through the output ports 200 connected in series at the bottom.

[0051] The output end is led out from one end of the anchor seat, and multiple sets are connected in series to meet the requirements of measuring mud level and water level at different locations of long-distance measurement objects.

[0052] The measurement method using the above-mentioned water level and sediment level measuring device includes:

[0053] When water flows through the inlet section of the measuring cavity, its velocity accelerates, causing vibration and deformation of the water level and sediment level monitoring ribs. The conditions that cause vibration and deformation of the water level and sediment level monitoring ribs are:

[0054] Water flows into the cavity 5 through the inflow side and out through the outflow side, which accelerates the water flow and causes the additional stiffness of the water level and mud level monitoring rib 2 to meet the design requirements of the minimum vibration frequency of the excitation water level and mud level monitoring rib 2.

[0055] The additional stiffness of the water level and mud level monitoring rib 2 caused by the accelerated water flow in cavity region 5 is:

[0056]

[0057] Where, k ω This indicates the additional stiffness caused by the acceleration of the water flow; C d ρ represents the flow load constant, which is the effect of the water flow on the water level and sediment level monitoring reinforcement under normal conditions in the irrigation canal under test; A represents the cross-sectional area of ​​the water level and sediment level monitoring reinforcement subjected to the water flow; V represents the water velocity.

[0058] The stiffness of the water level and mud level monitoring rib 2 is:

[0059] k = k0 + k ω

[0060] Where k represents the final stiffness of the water level and sediment level monitoring rib after the water flow accelerates, and k0 represents the initial stiffness of the water level and sediment level monitoring rib. ω This indicates the additional stiffness caused by the acceleration of the water flow;

[0061] The natural vibration frequency of the water level and sediment level monitoring rib 2 is obtained by calculating the stiffness of the water level and sediment level monitoring rib 2:

[0062]

[0063] Where f represents the vibration frequency of the water level and mud level monitoring bar, and m represents the mass of the water level and mud level monitoring bar.

[0064] The strain distribution is obtained by measuring the strain peak value and the position of the strain sensing unit inside the water level and mud level monitoring rib; when the mud level changes after the water level and mud level monitoring rib are submerged, the mud level height is directly obtained by measuring the change in the inflection point of the strain distribution.

[0065] The mode shape is obtained by strain time history and spectrum analysis of the strain sensing unit inside the water level and mud level monitoring rib; when the water level height submerged by the water level and mud level monitoring rib changes, the water level height is obtained by the change of the inflection point position of the mode shape.

[0066] The mud level height of the water level and mud level monitoring rib can be obtained by the following formula.

[0067]

[0068] Among them, Q 1 i h represents the curvature change corresponding to the i-th strain sensing unit within the water level and mud level monitoring rib when the mud level changes. m The height of the neutral axis of the water level and mud level monitoring rib is represented by ε, where i represents the i-th strain sensing unit. i ε represents the strain value of the water level and sediment level monitoring rib before the sediment level changes. * i This indicates the strain value of the water level and mud level monitoring rib after the mud level height changes;

[0069] When Q 1 i When the value is not zero, the position of the i-th strain sensing unit corresponds to the current mud level height.

[0070] The water level height of the water level and sediment level monitoring ribs can be obtained using the following formula.

[0071]

[0072] Among them, Q 2 ih represents the curvature change corresponding to the i-th strain sensing unit within the water level and sediment level monitoring rib when the water level changes. m The height of the neutral axis of the water level and sediment level monitoring rib is represented by , i represents the i-th strain sensing unit, and r represents the modal order. This indicates the modal curvature of the water level or sediment level monitoring ribs before a change in water level or sediment level. This indicates the modal curvature of the water level or mud level monitoring rib after a change in water level or mud level height.

[0073] When Q 2 i When the value is not zero, the position of the i-th strain sensing unit corresponds to the current water level.

[0074] First, the water flow velocity accelerates after passing through the inlet section of the measuring cavity, causing vibration and deformation of the water level and sediment level monitoring rib. Second, the strain peak value and position of the strain sensing unit inside the water level and sediment level monitoring rib are used to determine the water level and sediment level. Figure 4 The strain distribution can be obtained, and the point where the strain is 0 on the strain distribution curve is the inflection point P. When the mud level changes at the mud level monitoring rod after being submerged by water, such as Figure 5 The mud level height is directly obtained by observing the change in the inflection point position of the strain distribution (from inflection point P0 to inflection point P1). Finally, the mode shapes can be obtained through strain time history and spectrum analysis of the strain sensing unit inside the water level and mud level monitoring rib. When the water level height submerged above the water level and mud level monitoring rib changes, the water level height is obtained by observing the change in the inflection point position of the mode shapes. Figure 6 The results show a comparison of the sensor's measurement results under three working conditions for an irrigation canal with an internal height of 100cm. Condition 1 is a water level of 80cm without silt accumulation; Condition 2 is a water level of 60cm with silt accumulation of 20cm; and Condition 3 is a water level of 50cm with silt accumulation of 30cm. The results show that the water level and silt level monitoring ribs can effectively detect changes in water level, and the inflection point of their vibration mode perfectly matches the silt level, proving that the present invention meets the measurement requirements for simultaneously identifying both water and silt levels.

[0075] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A water level and sediment level measuring device, characterized in that, include: The installation sidewall (1), water level and mud level monitoring rib (2), water-retaining sidewall (3), and anchor seat (4) are installed. The installation sidewall (1), water level and mud level monitoring rib (2), and water-retaining sidewall (3) are all anchored on the anchor seat (4). The water level and mud level monitoring rib (2) is provided with multiple sets of strain sensing units (21) connected in series. A measurement cavity area (5) is formed between the installation sidewall (1) and the water-retaining sidewall (3). The water level and mud level monitoring rib (2) is centrally located in the measurement cavity area (5). The opening width of the water-outflow side of the measurement cavity area (5) is smaller than the diameter of the water level and mud level monitoring rib (2). The opening width of the water-inflow side of the measurement cavity area (5) is more than 1.5 times the diameter of the water level and mud level monitoring rib (2). The method for obtaining water level and sediment level using multiple sets of strain sensing units (21) connected in series is as follows: When the water flows through the inlet section of the measuring cavity, the flow velocity accelerates, causing the water level and mud level monitoring ribs to vibrate and deform. The strain distribution is obtained by measuring the strain peak value and the position of the strain sensing unit inside the water level and mud level monitoring rib; when the mud level changes after the water level and mud level monitoring rib are submerged, the mud level height is directly obtained by measuring the change in the inflection point of the strain distribution. The modal shape is obtained by strain time history and spectrum analysis of the strain sensing unit inside the water level and mud level monitoring rib; when the water level height that submerges the water level and mud level monitoring rib changes, the water level height is obtained by the change of the inflection point position of the modal shape. The curvature change corresponding to the strain distribution sensing element is: in, Q 1 i This indicates the curvature change corresponding to the i-th strain sensing unit within the water level and mud level monitoring rib (2) when the mud level changes. h m The neutral axis height of the water level and sediment level monitoring rib (2) is represented by ε. i ε represents the strain value of the water level and mud level monitoring rib (2) before the mud level height changes. * i This indicates the strain value of the water level and mud level monitoring rib (2) after the mud level height changes; when Q 1 i When the value is not zero, the position of the i-th strain sensing unit corresponds to the current mud level height; The curvature change corresponding to the strain sensing element of the modal vibration mode is: in, Q 2 i This indicates the curvature change corresponding to the i-th strain sensing unit within the water level and mud level monitoring rib (2) when the water level changes. h m Indicates the neutral axis height of the water level and sediment level monitoring rib (2). The curvature of the r-th mode corresponding to the i-th strain sensing unit in the water level or mud level monitoring rib (2) before the water level or mud level changes is indicated. The curvature of the r-th mode corresponding to the i-th strain sensing unit in the water level or mud level monitoring rib (2) after the water level or mud level height changes; when Q 2 i When the value is not zero, the position of the i-th strain sensing unit corresponds to the current water level.

2. The water level and sediment level measuring device according to claim 1, characterized in that, The mounting sidewall (1) and the water-blocking sidewall (3) are located on the surface of the measuring cavity area (5) and are either arc-shaped or smooth surfaces to achieve a stable water flow effect.

3. The water level and sediment level measuring device according to claim 1 or 2, characterized in that, The water level and mud level monitoring rib (2) is a composite material with superior flexibility and high durability; the stiffness of the water level and mud level monitoring rib (2) is much smaller than the stiffness of the installation side wall (1) and the water-blocking side wall (3).

4. The water level and sediment level measuring device according to claim 3, characterized in that, The composite material is carbon fiber, glass, or basalt fiber.

5. A method for measuring cement level, characterized in that, The water level and sediment level measuring device according to any one of claims 1-4 is used for measurement.

6. The cement level measurement method according to claim 5, characterized in that, Water flows into the cavity area (5) from the inflow side and out from the outflow side, thereby accelerating the water flow and causing the additional stiffness of the water level and mud level monitoring rib (2) to meet the design requirements of the minimum vibration frequency of the excitation water level and mud level monitoring rib (2). The additional stiffness of the water level and mud level monitoring rib (2) caused by the accelerated water flow in the cavity area (5) is: in, This indicates the additional stiffness caused by the acceleration of the water flow; ρ represents the flow load constant, which is the effect of the water flow on the water level and sediment level monitoring reinforcement under normal conditions in the irrigation canal under test; A represents the cross-sectional area of ​​the water level and sediment level monitoring reinforcement subjected to the water flow; V represents the water velocity. The stiffness of the water level and sediment level monitoring rib (2) is: in, This indicates the final stiffness of the water level and sediment level monitoring ribs after the water flow accelerates. This indicates the initial stiffness of the water level and sediment level monitoring reinforcement. This indicates the additional stiffness caused by the acceleration of the water flow; The natural vibration frequency of the water level and sediment level monitoring rib (2) is obtained by calculating the stiffness of the water level and sediment level monitoring rib (2): in, f This indicates the vibration frequency of the water level and sediment level monitoring ribs. m This indicates the quality of the water level and mud level monitoring reinforcement.

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