Wireless transmission compensation pressure type water gauge with wave reduction structure

Abstract

The invention provides a wireless transmission compensation pressure type water gauge with a wave reduction structure, which comprises a cylindrical main body, the cylindrical main body is provided with a mounting surface, and the plane of the mounting surface is vertical to the central axis of the cylindrical main body; the mounting surface is used for mounting a pressure sensor; a water inlet is formed in the bottom of the cylindrical main body; a first grid wave reduction structure and a second grid wave reduction structure are also arranged on the cylindrical main body; the first grid wave reduction structure and the second grid wave reduction structure are sequentially arranged in the water flow direction. The first grid wave reduction structure and the second grid wave reduction structure are each provided with a plurality of wave reduction teeth. The arrangement directions of the wave reduction teeth of the first grid wave reduction structure and the second grid wave reduction structure are perpendicular to each other; by applying the technical scheme, the influence of the water flow speed, the water flow acceleration and the water surge on the measurement precision of the pressure type water gauge can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of sensing and measurement and control, and in particular to a wireless transmission compensated pressure water gauge with a wave attenuation structure. Background Art

[0002] A pressure water gauge is a device that measures the hydrostatic pressure at a certain water depth through a pressure sensor and calculates the water depth. It measures the hydrostatic pressure at a certain position and uses the formula P = ρgh (where ρ is the density of water, g is the acceleration due to gravity, and h is the water depth) to obtain the water depth h at that position. Since the pressure water gauges are mostly installed in rivers, lakes, seas, etc. The water bodies in these places are not ideally static. Especially in rivers and streams, the water flow has a fixed direction, and the sea is prone to waves. The movement of the water body will carry an additional acceleration, that is

[0003] The pressure of the water body on the surface of the pressure sensor = hydrostatic pressure + additional pressure of the water body movement

[0004] This will pose a challenge to the accurate measurement of the pressure water gauge. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a wireless transmission compensated pressure water gauge with a wave attenuation structure to reduce the influence of water flow velocity, water flow acceleration, and water body surge on the measurement accuracy of the pressure water gauge.

[0006] To achieve the above purpose, the present invention adopts the following technical scheme: A wireless transmission compensated pressure water gauge with a wave attenuation structure, including a cylindrical main body, the cylindrical main body is provided with an installation surface, and the plane where the installation surface is located is perpendicular to the central axis of the cylindrical main body; the installation surface is used to install a pressure sensor; the bottom of the cylindrical main body is an inlet; the cylindrical main body is also provided with a first grid wave attenuation structure and a second grid wave attenuation structure; the first grid wave attenuation structure and the second grid wave attenuation structure are arranged in sequence along the water flow direction; both the first grid wave attenuation structure and the second grid wave attenuation structure are provided with a plurality of wave attenuation teeth. The setting directions of the wave attenuation teeth of the first grid wave attenuation structure and the second grid wave attenuation structure are perpendicular to each other.

[0007] In a preferred embodiment, the first grid wave attenuation structure is formed by a plurality of first wave attenuation teeth arranged parallel to each other in sequence to form a first wave attenuation net; the second grid wave attenuation structure is formed by a plurality of second wave attenuation teeth arranged parallel to each other in sequence to form a second wave attenuation net.

[0008] In a preferred embodiment, the planes where the first wave attenuation net and the second wave attenuation net are located are perpendicular to the central axis of the cylindrical main body.

[0009] In a preferred embodiment, the widths of the cross-sections of the first and second wave-damping teeth perpendicular to their length directions gradually increase in the water flow direction.

[0010] In a preferred embodiment, the cross-sections of the first and second wave-damping teeth perpendicular to their length directions are trapezoidal.

[0011] In a preferred embodiment, the cross-section of the cylindrical main body perpendicular to the central axis direction is composed of an arc and a line segment connected end to end.

[0012] In a preferred embodiment, the wave-damping teeth are provided with a tooth bottom width S1, a tooth top width S2, a tooth height hs, a tooth pitch Ms, a tooth pattern coefficient st, and a tooth arrangement form coefficient q;

[0013]

[0014] Where γ is the grid wave-damping value, representing the attenuation degree of the wave-damping teeth and the wave-damping net structure formed by them on the water body surge and waves; st is the tooth pattern coefficient, q is the tooth arrangement form coefficient, ω is the wave-damping amount adjustment coefficient; A is the wave-damping amount influence value, calculated by formula (2); hs is the tooth height, and Ms is the tooth center distance.

[0015]

[0016] Where g = S1 - S2, the larger the g value, the larger the γ value, and the better the wave-damping effect; μ and σ are function adjustment parameters;

[0017]

[0018] Where Ф represents the overall wave-damping effect value; H1 represents the wave-damping net spacing, H2 represents the distance between the wave-damping net and the sensor installation surface; a and b are the set values of the wave-damping net spacing and the distance between the wave-damping net and the sensor installation surface respectively, determined by the engineer through preliminary experiments, and λ is the adjustment coefficient.

[0019] In a preferred embodiment, it further includes a temperature sensor, an antenna, and a receiving terminal; the pressure sensor, the temperature sensor, and the antenna are connected to the receiving terminal.

[0020] In a preferred embodiment, a plurality of pressure sensors are arranged along the central axis direction of the cylindrical main body.

[0021] In a preferred embodiment, the differential value dp / dt of the water pressure change curve at the adjustment point, where p is the water pressure value, determines the size of the interval, and the calculation formula is as follows:

[0022]

[0023] Where T is the sampling and transmission interval, λ is the first adjustment parameter, and α is the second adjustment parameter; dp / dt is the water pressure change rate; as the change rate rises, it indicates that the external water level changes rapidly and timely feedback is required.

[0024] Compared with the prior art, the present invention has the following beneficial effects: reducing the influence of water flow velocity, water flow acceleration, and water body surge on the measurement accuracy of the pressure type water gauge. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the basic structure of the water gauge for the preferred embodiment of the present invention;

[0026] Figure 2 Cross-sectional view of the intersection of a cylinder and a plane for the preferred embodiment of the present invention;

[0027] Figure 3 Overall schematic diagram of the intersection of a cylinder and a plane for the preferred embodiment of the present invention;

[0028] Figure 4 Structural diagram of the single-layer grid type wave-damping net for the preferred embodiment of the present invention;

[0029] Figure 5 Schematic diagram of the wedge-shaped structure of the grid type wave-damping net for the preferred embodiment of the present invention;

[0030] Figure 6 Schematic diagram of the longitudinal section triangular wedge-shaped wave-damping teeth structure for the preferred embodiment of the present invention;

[0031] Figure 7 Schematic diagram of the longitudinal section trapezoidal wedge-shaped wave-damping teeth structure for the preferred embodiment of the present invention;

[0032] Figure 8 Side view of the double-layer grid type wave-damping net structure for the preferred embodiment of the present invention;

[0033] Figure 9 Bottom view of the double-layer grid type wave-damping net structure for the preferred embodiment of the present invention;

[0034] Figure 10 Wave-damping tooth structure parameters of the wedge-shaped grid type wave-damping net for the preferred embodiment of the present invention;

[0035] Figure 11 Trend diagram of the function value of formula (2) for the preferred embodiment of the present invention;

[0036] Figure 12 Schematic diagram of the terminal connection for the preferred embodiment of the present invention;

[0037] Figure 13 Inductive output curve of the pressure sensor for the preferred embodiment of the present invention;

[0038] Figure 14 Schematic structural diagram when multiple pressure sensors are set according to a preferred embodiment of the present invention. Detailed implementation manners

[0039] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0040] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further descriptions of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0041] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary implementation manners according to the present application; as used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or their combinations.

[0042] A wireless transmission compensation pressure water gauge with a wave attenuation structure, referring to Figures 1-14 , includes a cylindrical main body. The cylindrical main body is provided with an installation surface 3, and the plane where the installation surface is located is perpendicular to the central axis of the cylindrical main body; the installation surface is used to install a pressure sensor; the bottom of the cylindrical main body is a water inlet; the cylindrical main body is further provided with a first grid wave attenuation structure 1 and a second grid wave attenuation structure 2; the first grid wave attenuation structure 1 and the second grid wave attenuation structure 2 are arranged in sequence along the water flow direction; both the first grid wave attenuation structure 1 and the second grid wave attenuation structure 2 are provided with a plurality of wave attenuation teeth. The arrangement directions of the wave attenuation teeth 2 of the first grid wave attenuation structure 1 and the second grid wave attenuation structure are perpendicular to each other.

[0043] The first grid wave attenuation structure is formed by arranging a plurality of first wave attenuation teeth in parallel in sequence to form a first wave attenuation net; the second grid wave attenuation structure is formed by arranging a plurality of second wave attenuation teeth in parallel in sequence to form a second wave attenuation net. Specifically, the planes where the first wave attenuation net and the second wave attenuation net are located are perpendicular to the central axis of the cylindrical main body. The widths of the cross-sections of the first wave attenuation teeth and the second wave attenuation teeth along the direction perpendicular to their lengths gradually increase along the water flow direction. Specifically, the cross-sections of the first wave attenuation teeth and the second wave attenuation teeth along the direction perpendicular to their lengths are trapezoidal.

[0044] Specifically, the cross-section of the cylindrical main body along the direction perpendicular to the central axis is composed of an arc segment and a line segment connected end to end.

[0045] Since the flow of rivers and streams is from high to low, the water body may have an acceleration, which will exert a force on the pressure sensing surface of the pressure water gauge, causing the measured pressure to increase corresponding to the increase in the measured depth, and this increase is actually an error. Therefore, the water inlet of the pressure water gauge of the present invention is at the bottom of the water gauge body. This can avoid the interference of the laterally flowing water body on the water depth measurement.

[0046] In order to further reduce the influence of the surges or tides of the water flow entering from the bottom water inlet on the pressure sensor installed at the installation surface 3, the present invention provides two layers of mutually perpendicular wedge-shaped grid damping nets. The structure of a single-layer grid damping net is as Figure 1 shown. The damping net is composed of wedge-shaped damping teeth arranged in rows. The structure of the damping teeth is schematically shown as Figure 4 shown, and the wedge shape is larger at the bottom and smaller at the top. The longitudinal section structure of the damping teeth can be triangular or trapezoidal, and can present different individual and combined forms, such as Figure 5 shown, and Figure 6 and Figure 7 shown.

[0047] In actual use, the present invention adopts a structure in which two layers of grid damping nets are stacked on top of each other, and the directions of their damping teeth are perpendicular to each other. Figure 8 and Figure 9 are the side view and the bottom view respectively. As can be seen from Figure 9 , from the bottom view angle, the water flow passes through the two layers of damping grids, and the flow holes present a rectangular shape.

[0048] The present invention designs an algorithm for the structural parameter of the damping teeth of the wedge-shaped grid damping net. There are 6 parameters involved in the damping teeth: the bottom width S1 of the tooth, the top width S2 of the tooth, the tooth height hs, the tooth pitch Ms, the tooth style coefficient st, and the tooth arrangement form coefficient q.

[0049] To design the structure of the damping teeth, we need to first define a grid damping value γ, which indicates the attenuation degree of the damping teeth and the damping net structure formed by them on the water body surges and waves. If the grid damping value γ is larger, it means that the grid damping effect is more obvious, but at the same time, the refreshing effect of the water depth change on the pressure sensor is also more sluggish.

[0050]

[0051] Among them, st is the tooth style coefficient, q is the tooth arrangement form coefficient, ω is the damping amount adjustment coefficient; A is the damping amount influence value, which is calculated by formula (2); hs is the tooth height, and Ms is the tooth center distance.

[0052]

[0053] Among them, g = S1 - S2, Figure 11is the function trend line of formula (2). The larger the g value is, the larger the γ value is, and the better the wave reduction effect is. μ and σ are function adjustment parameters, which act on Figure 11 The tooth style coefficient st is shown in Figure 6 As shown in (1), (2), and (3), the wave reduction effect of the isosceles triangle in the longitudinal section is better than that of the right triangle. The st value of the isosceles triangle can be 1.2, and the st value of the right triangle can be 1.0. The specific value is confirmed by the user through experiments. The tooth arrangement coefficient q is as follows Figure 6 As shown in (4) and (5), the wave reduction effect of the opposite arrangement is better than that of the parallel arrangement. The q value of the opposite arrangement can be 1.2, and the q value of the parallel arrangement can be 1.0.

[0054] like Figure 1 As shown, in addition to the tooth structure of the grid, the wave reduction effect of the wave reduction grid is also affected by the wave reduction grid spacing H1 and the distance H2 between the wave reduction grid and the sensor installation surface. Therefore, the system Φ is determined by the following formula:

[0055]

[0056] Where a and b are the setting values ​​of the distance between the wave-reduction nets and the distance between the wave-reduction nets and the sensor installation surface, respectively, which are determined by engineers through preliminary experiments, and λ is the adjustment coefficient, which is determined by the actual situation.

[0057] The setting steps are as follows:

[0058] Step 1: Determine Ф by theoretical deduction, experiment and analysis based on the average annual flow velocity, water density and impurity level of the water body (river) using formula (3)

[0059] Step 2: Inversely infer (1)γ from Φ

[0060] Step 3: Calculate the parameters on the right side of γ

[0061] Each parameter is determined through theoretical deduction, field experiments and specific analysis.

[0062] The measurement principle of the pressure type water gauge is to obtain the pressure value P by measuring the water pressure at the water level on the membrane surface of the single pressure sensor (not the differential pressure sensor), and then obtain the water depth h at that location by using the formula P = ρgh (where ρ is the density of water, g is the acceleration of gravity, and h is the water depth). Therefore, the atmospheric pressure superimposed on the water pressure will affect the actual measured P value, so the atmospheric pressure needs to be subtracted. In addition, the temperature of the water body itself will affect the density ρ of the water, so the temperature of the water must also be measured.

[0063] like Figure 12 As shown, the terminal device of the present invention consists of two parts:

[0064] The water level gauge measures the water pressure (used to find the water depth h) and the water temperature (used to get the water density parameter ρ), and then transmits the data wirelessly to the receiving terminal on the shore through a communication chip supporting the LORA protocol. In addition to receiving data from the water level gauge, the receiving terminal also measures atmospheric pressure, atmospheric temperature, and atmospheric humidity. The atmospheric temperature and humidity are used to calibrate the atmospheric pressure value, and the water level pressure value obtained by the water level gauge sampling is subtracted from the atmospheric pressure value to obtain the actual pressure value. Then, the water depth of the water level pressure sensor of the water level gauge can be obtained through the formula P = ρgh (where ρ is the density of water, g is the acceleration of gravity, and h is the water depth). The depth of the water in the water area can be further obtained by combining the altitude positioning of the water level gauge and its own length information.

[0065] The innovative sampling compensation mechanism can improve the measurement accuracy of the pressure water gauge.

[0066] like Figure 13 As shown, the inductive output curve of the pressure sensor is not necessarily a straight line, but often presents the shape of an upward curve, and the output voltage shows an upward trend as the pressure increases, but it is not on a straight line. Therefore, a direct line segment between two points on the curve can be used in a local area to approximate the output relationship of this curve (similar to the red marked line segment ab and line segment bc) to obtain a relatively accurate measurement value. Usually, the output curve of the pressure sensor is not necessarily known to the user, and the curve may also produce actual deviations due to changes in the complex external environment. In this case, it is necessary to manually calibrate the equipment with a small line segment linear approximation before use, that is, manually take several points at different water depths to measure its output voltage, use the pressure value inferred by the formula as the horizontal coordinate, and use the actual voltage output value of the sensor as the vertical coordinate to fit the curve to obtain the corresponding curve.

[0067] However, in this way, each sensor needs to be manually calibrated when used in different scenarios, which is cumbersome and labor-intensive, very inconvenient, and greatly increases the deployment cost. The present invention proposes a small line segment underwater self-calibration error compensation mechanism. Figure 14 As shown, increase the number of sensors and arrange more than two sensors on the water gauge. Figure 14Taking three as an example, they are located at positions a, b, and c respectively. The straight-line distance between a and b is s1, and the straight-line distance between b and c is s2; x1, x2, and x3 are the x coordinates of a, b, and c respectively, and the projected values of points a, b, and c on the x-axis), where the intervals s1 and s2 can be equal or unequal. By measuring the pressure values p1, p2, and p3 at positions a, b, and c respectively, three point pairs (x1, p1), (x2, p2), and (x3, p3) can be formed. By using the straight-line formula for two points in analytic geometry, the line segment 1 determined by (x1, p1) and (x2, p2) and the line segment 2 determined by (x2, p2) and (x3, p3) can be obtained. In this way, the area from a to c can be divided into two regions according to a->b and b->c and different straight-line slopes can be used for calculation, so as to approximately approximate the original output curve and reduce the error.

[0068] The advantages of this process are as follows: First, it can be self-calibrated by the device without manual intervention; second, it can reduce the error of directly using the two end points for linear fitting (using piecewise determination of the slope).

[0069] The pressure water gauge is generally installed in a reservoir or a river. Usually, the electronic system is only powered by a battery and it is difficult to obtain replenishment. Therefore, low power consumption and energy-saving mechanisms are important issues that need to be considered. Sometimes the river water level changes slowly, then the water pressure sampling interval and the wireless communication time interval can be gradually increased appropriately; and sometimes the river water level changes rapidly, then the water pressure sampling interval and the wireless communication time interval need to be shortened. Since the power consumption generated by sensor sampling and wireless communication is the main part of the system, while the power consumption of the microcontroller in standby is very small, adopting a mechanism to adaptively adjust the sampling and transmission time intervals according to the water pressure change rate can significantly reduce the power consumption of the entire system, extend the life of the device in the case of a one-time assembled battery without other power supply supplements, and improve the device's survival period.

[0070] This method uses the differential value dp / dt (i.e., the tangent slope of the water pressure change curve at the adjustment point) of the recorded water pressure change curve, where p is the water pressure value, to determine the size of the interval. The calculation formula is as follows:

[0071]

[0072] Where T is the sampling and transmission interval, λ is the adjustment parameter 1, α is the adjustment parameter 2, both of which are specified by the engineer according to the actual situation; dp / dt is the water pressure change rate. As the change rate increases, it indicates that the external water level changes rapidly and timely feedback is required. In order to prevent missed reports or loss of timeliness, the sampling interval must be shortened; as the change rate decreases, it indicates that the external water level changes slowly, and the sampling interval can be increased to save precious energy.

Claims

1. A wireless transmission compensated pressure type water gauge with a wave reduction structure, characterized in that, It includes a cylindrical main body, and the cylindrical main body is provided with an installation surface, and the plane where the installation surface is located is perpendicular to the central axis of the cylindrical main body; the installation surface is used for installing a pressure sensor; the bottom of the cylindrical main body is a water inlet; the cylindrical main body is also provided with a first grid wave attenuation structure and a second grid wave attenuation structure; the first grid wave attenuation structure and the second grid wave attenuation structure are arranged in sequence along the water flow direction; both the first grid wave attenuation structure and the second grid wave attenuation structure are provided with a plurality of wave attenuation teeth. The setting directions of the wave attenuation teeth of the first grid wave attenuation structure and the second grid wave attenuation structure are perpendicular to each other.

2. The wireless transmission compensation pressure type water gauge with a wave attenuation structure according to claim 1, wherein, The first grid wave attenuation structure is formed by a plurality of first wave attenuation teeth arranged in parallel in sequence to form a first wave attenuation net; the second grid wave attenuation structure is formed by a plurality of second wave attenuation teeth arranged in parallel in sequence to form a second wave attenuation net.

3. The wireless transmission compensation pressure type water gauge with a wave attenuation structure according to claim 2, characterized in that, The planes where the first wave attenuation net and the second wave attenuation net are located are perpendicular to the central axis of the cylindrical main body.

4. The wireless transmission compensation pressure type water gauge with a wave attenuation structure according to claim 3, characterized in that, The widths of the cross-sections of the first wave attenuation teeth and the second wave attenuation teeth along the direction perpendicular to their lengths gradually increase along the water flow direction.

5. A wireless transmission compensated pressure type water gauge with a wave attenuation structure according to claim 3, characterized in that, The cross-sections of the first wave attenuation teeth and the second wave attenuation teeth along the direction perpendicular to their lengths are trapezoidal.

6. The wireless transmission compensated pressure type water gauge with a wave reduction structure according to claim 1, characterized in that, The cross-section of the cylindrical main body along the direction perpendicular to the central axis is composed of an arc and a line segment connected end to end.

7. A wireless transmission compensation pressure water gauge with a wave reduction structure according to claim 1, characterized in that, The wave attenuation teeth are provided with a tooth bottom width S1, a tooth top width S2, a tooth height hs, a tooth pitch Ms, a tooth pattern coefficient st, and a tooth arrangement form coefficient q. Where γ is the grid wave attenuation value, representing the attenuation degree of the wave attenuation teeth and the wave attenuation net structure formed by them on the water body surge and waves; st is the tooth pattern coefficient, q is the tooth arrangement form coefficient, ω is the wave attenuation amount adjustment coefficient; A is the wave attenuation amount influence value, which is calculated by formula (2); hs is the tooth height, and Ms is the tooth center distance. Where g = S1 - S2, the larger the g value, the larger the γ value, and the better the wave attenuation effect; μ and σ are function adjustment parameters. Where Ф represents the overall wave attenuation effect value; H1 represents the wave attenuation net spacing, H2 represents the distance between the wave attenuation net and the sensor installation surface; a and b are the set values of the wave attenuation net spacing and the distance between the wave attenuation net and the sensor installation surface, respectively, which are determined by engineers through preliminary experiments, and λ is the adjustment coefficient.

8. A wireless transmission compensation pressure type water gauge with a wave reduction structure according to claim 1, characterized in that, It also includes a temperature sensor, an antenna, and a receiving terminal; the pressure sensor, the temperature sensor, and the antenna are connected to the receiving terminal.

9. A wireless transmission compensated pressure type water gauge with a wave reduction structure according to claim 1, characterized in that, A plurality of pressure sensors are arranged along the central axis direction of the cylindrical main body.

10. A wireless transmission compensation pressure type water gauge with a wave reduction structure according to claim 1, characterized in that, The differential value dp / dt of the water pressure change curve at the adjustment point, where p is the water pressure value, determines the size of the interval, and the calculation formula is as follows: Where T is the sampling and sending interval, λ is the first adjustment parameter, α is the second adjustment parameter; dp / dt is the water pressure change rate; as the change rate rises, it indicates that the external water level changes quickly and timely feedback is required.

Images