Fully automatic overtopping event moment sensing and recording device

Abstract

The present invention relates to a fully automatic overtopping event occurrence sensing and recording device. The purpose of the present invention is to provide a sensitive and accurate fully automatic overtopping event occurrence sensing and recording device. The technical solution of the present invention is: a fully automatic overtopping event occurrence sensing and recording device, characterized in that: a seawall model is provided, a water collection tank is provided behind the seawall model and a weight sensor capable of sensing the weight change of the water collection tank is provided, an overtopping signal acquisition unit capable of generating a potential difference change when encountering an overtopping water body is provided on the top of the seawall model, the overtopping signal acquisition unit circuit is connected to a data acquisition box, and the data acquisition box obtains a potential difference change curve as a basis for judging the occurrence of an overtopping event. The present invention is applicable to the field of physical model tests in the direction of coastal engineering.

Description

Technical Field

[0001] The invention relates to a fully automatic overtopping event occurrence time sensing and recording device, which is applicable to the field of physical model tests in the direction of coastal engineering. Background Art

[0002] At present, there are two main methods used in physical model experiments in coastal engineering to determine the time when overtopping occurs: (1) Place a wave height meter on the top of the dike. When overtopping occurs, the water level value displayed by the wave height meter will increase. The time when overtopping occurs can be determined based on the change time of the wave height meter data.

[0003] (2) A weight sensor is connected to the water collection tank behind the seawall model. After an overtopping event occurs, the overtopping water flows over the seawall model and falls into the water collection tank behind the seawall. The weight sensor connected to the water collection tank senses the weight change of the water collection tank, and its output data increases in response. The time point of the overtopping event can be determined based on the change time of the weight sensor data.

[0004] However, the existing method of measuring using a wave height meter on the top of the dike has the disadvantage of insensitive data feedback. The output data of the wave height meter has requirements on the lower limit of the size of the overtopping water body. If the volume of the overtopping water body is too small, the change amplitude of the wave height meter output data may be too small or even no change, resulting in the overtopping event being missed or a large measurement error at the time of occurrence, making the test results inaccurate.

[0005] The existing method of using a weight sensor to sense the total weight change of the water collection tank behind the seawall model and infer the time when the overtopping event occurs also has the problem of insensitive data feedback and delayed measurement results. Since the weight sensor in the water collection tank needs to measure the total overtopping volume, it has a relatively weak ability to sense and distinguish small overtopping events. Therefore, after a small overtopping event occurs, the sensor feedback data may not change significantly or even remain unchanged, causing measurement errors. In addition, during the wave overtopping physical model test, there is a long-term irregular oscillation on the surface of the liquid in the water collection tank behind the model, resulting in obvious fluctuations in the output result of the weight sensor, which can easily make the weight change of the water collection tank caused by some overtopping events difficult to detect, so that the overtopping event is missed, resulting in large test measurement errors. Summary of the invention

[0006] The technical problem to be solved by the present invention is: in view of the above-mentioned existing problems, a sensitive and accurate fully automatic overtopping event occurrence time sensing and recording device is provided.

[0007] The technical solution adopted by the present invention is: a fully automatic overtopping event occurrence time sensing and recording device, characterized in that: it has a seawall model, a water collection tank is arranged behind the seawall model and is equipped with a weight sensor that can sense the weight change of the water collection tank, and an overtopping signal acquisition unit is arranged on the top of the seawall model that can generate a potential difference change when encountering an overtopping water body, and the overtopping signal acquisition unit circuit is connected to a data acquisition box, and the data acquisition box obtains a potential difference change curve as a basis for judging the occurrence of an overtopping event.

[0008] A drainage plate for guiding overtopping water to flow into a water collecting tank behind the seawall model is provided on the top of the seawall model, and the overtopping signal collection unit is fixed on the drainage plate.

[0009] A portion of the guide plate overlaps with the top of the seawall model, and another portion is located behind the seawall model and tilted downward at an angle of 40° from the horizontal plane.

[0010] The overtopping signal acquisition unit has a positive metal strip and a negative metal strip parallel to each other, with a certain distance between the positive metal strip and the negative metal strip and fixed on an insulating base; the insulating base completely wraps the contact part of the drainage plate with the water flow, ensuring that the overtopping water only contacts the metal strip on the base, avoiding the water flowing through the drainage plate to form an extra loop and cause reading errors;

[0011] The data acquisition box is connected to the positive metal strip and the negative metal strip via wires to obtain the change of the potential difference between the positive metal strip and the negative metal strip.

[0012] A hydrophobic thin layer is formed on the insulating base between the positive electrode metal strip and the negative electrode metal strip.

[0013] The hydrophobic thin layer is formed by a hydrophobic liquid coated on the insulating base.

[0014] The insulating base is made of electrical tape.

[0015] The overpass signal collection unit circuit is connected to a DC power supply and a fixed resistor.

[0016] The fixed resistor is a metal film resistor with a resistance of 200 kΩ. After the resistor is connected in series with the metal strip, the voltage value between the metal strips changes most significantly, and the sensitivity of the instrument is properly controlled, so as not to be too sensitive and cause false detection of non-overtopping events such as splashing liquid drops.

[0017] The width of the positive and negative metal strips is 8 mm, and the spacing is 10 to 15 mm. The combination of the width and spacing of the metal strips can maximize the sensitivity and accuracy of the device, ensuring the most timely sensing of tiny overtopping events and the most significant data feedback. When the distance is too short, the instrument is too sensitive, and slightly larger splashing water droplets will cause obvious fluctuations in the instrument output data; when the distance is too far, the instrument is not sensitive, and the fluctuations in the instrument output data are not obvious when some small overtopping events occur, which are easily mixed with the fluctuations caused by water droplets, causing measurement errors.

[0018] The beneficial effects of the present invention are as follows: the present invention has a simple structure and low cost, and the overtopping signal acquisition unit can timely and accurately reflect the occurrence time of the overtopping event, and the time interval between the occurrence of the overtopping event and the data feedback is much shorter than the 0.5s lag time of the prior art. At the same time, since the overtopping signal acquisition unit in the present invention can generate a potential difference change when encountering an overtopping water body, it can still give clear feedback for small overtopping events (overtopping volume of about 20ml), ensuring that small overtopping events will not be missed in the physical model test.

[0019] In the present invention, a guide plate is arranged on the top of the seawall model to guide the overtopping water to flow into the water collecting tank behind the seawall model, thereby improving the sensing and distinguishing capabilities of tiny overtopping events. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 , Figure 2 It is a structural schematic diagram of an embodiment.

[0021] Figure 3 Schematic diagram of a circuit of an embodiment.

[0022] Figure 4 Graph showing the change in potential difference in the embodiment.

[0023] Figure 5 It is a comparison diagram of the overtopping moment and the overtopping water body increase moment in the embodiment.

[0024] 1-1, positive metal bar; 1-2, negative metal bar; 2, insulating base; 3, drainage plate; 4, data acquisition box; 5, fixed resistor; 6, DC power supply; 7, water collection tank with weight sensor behind the dike; 8, water collection baffle. DETAILED DESCRIPTION

[0025] like Figure 1-2 As shown, this embodiment is a fully automatic overtopping event occurrence sensing and recording device, which has a seawall model, a water collection tank is provided behind the seawall model and is equipped with a weight sensor that can sense the weight change of the water collection tank. When the weight sensor senses the weight change of the water collection tank, it indicates that the overtopping event has occurred.

[0026] In this embodiment, a drainage plate is fixed on the top of the seawall model. About 1 / 5 of the drainage plate overlaps with the top of the seawall model, and the remaining 4 / 5 is located behind the seawall model, tilted downward at an angle of about 40° from the horizontal plane to guide the overtopping water into the water collection tank behind the dike. The overlapped part of the drainage plate and the fixed part of the seawall model has two screw holes arranged at an interval of 30 cm, and is fixed to the screw hole position on the top of the seawall model with hexagon socket screws to facilitate subsequent disassembly. The overlapped part of the drainage plate and the top of the seawall is tilted toward the back of the dike at an angle of 5° to 10°, and the top of the dike is also coated with hydrophobic liquids such as silicone and oil to form a hydrophobic layer, so as to minimize the retention of overtopping water on the top of the dike, and reduce the erroneous measurement results caused by the drop of the retained water on the top of the dike when there is no overtopping event.

[0027] In this embodiment, two vertical upward baffles are provided at both ends of the guide plate, and the edges of the baffles and the wall of the wave tank are sealed with silicone to ensure that all the over-wave water passes through the guide plate and flows to the back of the dike through the two parallel metal strips on the plate.

[0028] In this example, an overtopping signal collection unit is provided at the top of the seawall model. The overtopping signal collection unit has a positive metal strip and a negative metal strip parallel to each other. The positive metal strip and the negative metal strip are fixed to the drainage plate via an insulating base. The positive metal strip and the negative metal strip are parallel to the length direction of the seawall model. The width of the metal strip is 8 mm, the length is consistent with the length of the seawall model, and the spacing is 10 to 15 mm.

[0029] In this embodiment, the insulating base is made of electrical tape and is pasted on the drainage board parallel to the direction of the seawall, and the two metal strips are fixed within the range of the electrical tape. A hydrophobic liquid such as silicone or oily liquid is applied to the range between the two metal strips on the insulating base to form a hydrophobic thin layer, so as to quickly drain the water in the area between the two metal strips after the overtopping water passes, eliminate the water droplets between the metal strips, ensure that the instrument reading quickly returns to the initial value, and reduce the redundant measurement errors in the measurement readings.

[0030] like Figure 3 As shown, in this embodiment, the overpass signal acquisition unit is connected in series with a DC power supply and a fixed resistor via a wire, wherein the wire is respectively connected to the positive metal bar and the negative metal bar in the overpass signal acquisition unit, and a data acquisition box is connected in parallel to the overpass signal acquisition unit, and the data acquisition box obtains the potential difference change curve between the positive metal bar and the negative metal bar.

[0031] In this example, the fixed resistor uses a metal film resistor with a resistance of 200kΩ, which is connected in series between a metal strip and a DC power supply. Metal film resistors have excellent characteristics such as good stability and little environmental impact, which ensures the stability and accuracy of the instrument output data. The DC power supply is a 9V DC power supply, and the voltage value is kept within the allowable range of the data acquisition box. The data acquisition box allows a voltage range of -10V to 10V. The positive and negative poles of the acquisition box are connected to the metal strips corresponding to the positive and negative poles of the power supply through wires. The differential mode is used to record the analog signals input at both ends in the form of the difference between the two ends of the signal, and output it as a data file.

[0032] The method of using this embodiment is as follows:

[0033] The metal strip, data acquisition box, fixed resistor and DC power supply are connected. When connecting the metal strip to the wire, be sure to weld or screw the wire tightly to the metal strip, and wrap the connection point with insulating tape to prevent the over-wave water from being retained on the wire after the instrument is used for a long time, affecting the insulation between the two metal strips and causing the instrument output data to be unstable or inaccurate.

[0034] After the connection is completed, a hydrophobic liquid such as silicone / oil is applied between the two parallel metal strips, and a fixed power supply is connected to generate a potential difference between the positive and negative poles of the circuit.

[0035] Turn on the data acquisition box and start the wave experiment. When an overtopping event occurs, the overtopping water flows over the guide plate, causing the potential of the two metal strips to change. The data acquisition box automatically analyzes the potential difference between the two metal strips and records it in the data file.

[0036] The data acquisition box automatically analyzes the potential difference between the metal strips and converts the analog signal into data and outputs it into a data file, such as Figure 4 The result is shown in the figure. The curve in the figure is the potential difference change curve between the two metal strips recorded by the data acquisition box during the experiment. The change of potential difference indicates the change of water volume between the two metal strips. Each downward trend indicates the occurrence of an overtopping event. When the downward curve falls to the bottom, it can be regarded as the overtopping event has completely occurred.

[0037] Figure 5 This is a comparison diagram of the time when the overtopping amount in the water collection tank increases and the time when the overtopping occurs obtained from the potential difference change curve in this embodiment. The measured time of occurrence in this example is consistent with the time when the overtopping water body increases sensed by the weight sensor in the water tank behind the dike, and the trend line basically conforms to the trend of y=x, indicating that the measurement results of the embodiment are accurate and highly precise.

Claims

1. A fully automatic overtopping event sensing and recording device, characterized in that: A seawall model is provided, a water collection tank is arranged behind the seawall model and a weight sensor capable of sensing weight changes of the water collection tank is provided, an overtopping signal acquisition unit capable of generating potential difference changes when encountering overtopping water is provided on the top of the seawall model, the overtopping signal acquisition unit circuit is connected to a data acquisition box, and the data acquisition box acquires a potential difference change curve as a basis for judging the occurrence of an overtopping event; A drainage plate is provided on the top of the seawall model for guiding the overtopping water to flow into the water collection tank behind the seawall model, and the overtopping signal collection unit is fixed on the drainage plate; A portion of the guide plate overlaps with the top of the seawall model, and another portion is located behind the seawall model and tilted downward at an angle of 40° from the horizontal plane; The overtopping signal collection unit has a positive metal strip and a negative metal strip parallel to each other, a certain distance is left between the positive metal strip and the negative metal strip and they are fixed on an insulating base; The data acquisition box is connected to the positive metal strip and the negative metal strip via wires to obtain the change of the potential difference between the positive metal strip and the negative metal strip; A hydrophobic thin layer is formed on the insulating base between the positive electrode metal strip and the negative electrode metal strip; The insulating base is made of electrical tape.

2. The fully automatic overtopping event occurrence sensing and recording device according to claim 1, characterized in that: The hydrophobic thin layer is formed by a hydrophobic liquid coated on the insulating base.

3. The fully automatic overtopping event occurrence sensing and recording device according to claim 1, characterized in that: The overpass signal collection unit circuit is connected to a DC power supply and a fixed resistor.

4. The fully automatic overtopping event occurrence sensing and recording device according to claim 3, characterized in that: The fixed resistor is a metal film resistor with a resistance of 200 kΩ.

5. The fully automatic overtopping event occurrence sensing and recording device according to claim 1, characterized in that: The span of the positive electrode metal strip and the negative electrode metal strip is 8 mm, and the spacing is 10-15 mm.

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