System for measuring liquid flow rate and method for measuring liquid flow rate

Abstract

For example, to provide a simple, inexpensive, and practical system and method for measuring the flow rate of liquids, such as when it is necessary to measure the flow rate of underground drainage. [Solution] A system for measuring the flow rate of a liquid, comprising a flap gate and an openness sensor, wherein the flap gate has a lid and is configured to open the lid in response to the pressure of the liquid, and the openness sensor acquires openness information indicating the degree of openness of the lid, and the flow rate of the liquid is measured based on the openness information.

Description

Technical Field

[0001] The present invention relates to a system for measuring the flow rate of a liquid and a method for measuring the flow rate of a liquid.

Background Art

[0002] Conventionally, flow meters such as electromagnetic flow meters, ultrasonic flow meters, and turbine flow meters are known. In addition, Non-Patent Document 1 describes a method of using a flap gate to monitor the flow rate of sewage.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, for example, when it is desired to measure the flow rate of underground drainage, existing flow meters have problems such as being expensive, difficult to install, and unable to measure the flow rate of liquids containing solids because they block the flow path. In addition, the method described in Non-Patent Document 1 has a problem that it can only be applied in a very limited state of the semi-submerged state of the sewer pipe. Furthermore, the method described in Non-Patent Document 1 requires obtaining two parameters that change moment by moment, namely, the angle of the lid of the flap gate and the height from the bottom surface to the water surface of the semi-submerged sewer pipe (pipe), and the measurement of the flow rate is difficult and complicated. In addition, since these parameters are obtained using a protractor and a ruler, the method is extremely lacking in practicality.

Means for Solving the Problems

[0005] According to one aspect of the present invention, a system for measuring the flow rate of a liquid is provided, comprising a flap gate and an openness sensor, wherein the flap gate has a lid and is configured to open the lid in response to the pressure of the liquid, the openness sensor acquires openness information indicating the degree of openness of the lid, and the flow rate of the liquid is measured based on the openness information.

[0006] According to this embodiment, a simple, inexpensive, and practical flow measurement system can be provided. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing the installation status of the flap gate and its surrounding components of a flow measurement system. [Figure 2] This is a schematic diagram showing a flap gate in its initial state (when no liquid is flowing through the piping). [Figure 3] This is a diagram showing the configuration overview of the flow measurement system. [Figure 4] The non-submerged state (where the flap gate is not submerged in the liquid) (Figure 4(a)), the semi-submerged state (where the flap gate is partially submerged in the liquid) (Figure 4(b)), and the submerged state (where flap gate 2 is submerged in liquid L) (Figure 4(c)) are schematically shown. [Figure 5] This is a block diagram showing the functions realized by the processor and other components in an information processing device. [Figure 6] This is an activity diagram showing an overview of the processes performed using the flow measurement system. [Figure 7] These are schematic diagrams illustrating examples of installation variations for flow measurement systems (Figures 7(a) and 7(b)). [Modes for carrying out the invention]

[0008] [Embodiment] Embodiments of this disclosure will be described below with reference to the drawings. The various features shown in the embodiments below are interchangeable.

[0009] Incidentally, the program for implementing the software appearing in one embodiment may be provided as a non-transitory computer-readable medium, or it may be provided as a downloadable medium from an external server, or it may be provided so that the program is launched on an external computer and its functions are realized on a client terminal (so-called cloud computing).

[0010] Furthermore, in various information processing according to one embodiment, an input and an output corresponding to the input can be realized. Here, as long as an output is obtained as a result of the input, the form of the information referenced in such information processing (hereinafter referred to as "reference information") is not limited. The reference information may be, for example, rule-based information such as a database, a lookup table, or a predetermined function (including a decision formula such as a regression equation constructed by a statistical method), or a pre-trained model that has learned the correlation between input and output in advance, or a large-scale language model that can output a desired result by inputting a prompt.

[0011] Furthermore, in one embodiment, "part" may include, for example, hardware resources implemented by a circuit in a broad sense, and the information processing of software that can be specifically realized by these hardware resources. Also, in one embodiment, various types of information are handled, and this information can be represented, for example, by the physical values ​​of signal values ​​representing voltage and current, the high or low values ​​of signal values ​​as a set of binary bits composed of 0s or 1s, or by quantum superposition (so-called qubits), and communication and calculations can be performed on a circuit in a broad sense.

[0012] Furthermore, a circuit in a broad sense is a circuit realized by combining at least a suitable combination of circuits, circuits, processors, and memory. The processor may be a general-purpose processor or a dedicated circuit. In other words, it includes application-specific integrated circuits (ASICs), programmable logic devices (for example, simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs)), etc.

[0013] [Flow Measurement System] First, the hardware configuration of a flow rate measurement system 1 according to one embodiment of this disclosure will be described. Figure 1 is a schematic diagram showing the installation state of the flap gate and its surrounding configuration of the flow rate measurement system. Figure 2 is a schematic diagram showing the flap gate in a state where no liquid is flowing through the piping (initial state). Figure 3 is a block diagram showing an overview of the configuration of the flow rate measurement system. The flow rate measurement system 1 is a system for measuring the flow rate of liquid L. Liquid L is not particularly limited, but can be water such as river water, groundwater, purified water, agricultural water, or industrial water. Liquid L may also contain some solid matter. As shown in Figure 1, the flow rate measurement system 1 comprises a flap gate 2 and an openness sensor 3.

[0014] The system exemplified in flow measurement system 1 consists of one or more devices or components. Therefore, the system may include elements selected from the group of configurations described below. Elements not selected may not be included in the system but may be connected to the selected elements as external elements.

[0015] (Flap Gate) The flap gate 2 is connected to the drain outlet P1 of the pipe P. The pipe P to which the flap gate 2 is connected is not particularly limited, but for example, it is a buried culvert (underground drainage facility) provided in agricultural land.

[0016] In regions such as Japan with a particularly humid climate, in agricultural lands such as paddy fields, fields, and paddy field conversion fields, in order to prevent problems such as poor growth of crops due to waterlogging and disruption of work plans due to work being affected by the weather, drainage is often carried out by buried culverts. However, due to the mixing of impurities such as soil and the deterioration of facilities, etc., the drainage function of the buried culvert may decline. Monitoring and diagnosis of the drainage function of the buried culvert disposed underground are generally carried out by measuring the flow rate of the water flowing near the drain outlet of the buried culvert during or after rainfall. Conventionally, the flow rate has been measured by an electromagnetic flowmeter.

[0017] However, electromagnetic flowmeters are generally expensive. Also, the fixing method of electromagnetic flowmeters is complicated, and it is necessary to extend the pipe near the drain outlet of the buried culvert horizontally. That is, there are many obstacles for electromagnetic flowmeters to be widely popularized. Regarding other existing flowmeters as well, flowmeters such as ultrasonic flowmeters, Coriolis flowmeters, and Karman vortex flowmeters may be more expensive than electromagnetic flowmeters. Flowmeters such as relatively inexpensive float type flowmeters and turbine type flowmeters are not suitable for installation in pipes such as buried culverts where solids such as sediment and parts of plants can mix into the flow path. That is, there was no flowmeter with high versatility, low cost, and sufficient practicality.

[0018] Therefore, after diligent study, the inventors have invented the flow rate measurement system 1. As described above, the flow rate measurement system 1 has a simple configuration, making it possible to measure flow rates inexpensively, such as for verifying the performance of underground drainage pipes. The flow rate measurement system 1 can be installed simply by fitting the flap gate 2 into the drainage port P1 of a pipe P such as an underground drainage pipe. Therefore, with the flow rate measurement system 1, the method of fixing the equipment is simple, and there is no need to extend the pipe P. Furthermore, since the flow rate measurement system 1 does not require a structure that obstructs the flow path for flow rate measurement, it can be installed even in pipes P that may contain solid matter, such as underground drainage pipes. Moreover, as will be described later, it has sufficient measurement accuracy.

[0019] The flap gate 2 comprises a main body 21 and a lid 22 that is openable and closable and connected to the main body 21 via a connector 23. Liquid L flowing through the piping P flows out of the flap gate 2 through an opening 212 in the main body 21. At this time, the lid 22 is configured to open in response to the pressure of the liquid L. The shape and constituent materials of the flap gate 2 are not particularly limited, as long as the lid 22 is configured to open outwards to the outside of the flap gate 2 in response to the pressure of the liquid L flowing through the pipe P, and not to open inwards to the flap gate 2 in response to the pressure of fluids (liquid and gas) from outside the flap gate 2.

[0020] For example, the shape of the main body 21 only needs to be such that it can be fixed to the drain port P1 of the pipe P, and may have a tubular shape such as a circular pipe or a square pipe, or a plate shape such as a flat plate or a curved plate. Also, as shown in Figure 1, the main body 21 may be fitted into the pipe P, or it may be attached to the pipe P by fixing parts such as wire or screws. The lid 22 may have a plate shape such as a flat plate or a curved plate, or in addition to a plate shape, the lid 22 may have an edge along the periphery of the main body 21. The connecting body 23 is, for example, an opening and closing mechanism such as a hinge.

[0021] However, when the flow rate measurement system 1 is used to measure the flow rate of a drainage system in farmland, the flap gate 2 is preferably a so-called socket-type flap gate, as shown in Figure 1. In this case, the flap gate 2 can be installed simply by fitting it into the pipe P. In the example shown in Figure 1, the main body 21 has a fitting portion 211. The outer diameter of the fitting portion 211 is smaller than the inner diameter of the pipe P, and the fitting portion 211 is fitted inside the pipe P. Of course, the inner diameter of the fitting portion 211 may be larger than the outer diameter of the pipe P, and the fitting portion 211 may be fitted outside the pipe P. Alternatively, the main body 21 may not have a fitting portion 211, and the main body 21 itself may be fitted into the pipe P.

[0022] The materials used to construct the flap gate 2 are not particularly limited and are preferably set appropriately according to the application of the flow measurement system 1. For example, when the flow measurement system 1 is used to measure the flow rate of an underground drain in farmland, the flap gate 2 is preferably made of a lightweight material such as resin or light metal. On the other hand, when the flow measurement system 1 is used to measure the flow rate at locations with large flow rates, such as river sluice gates and backflow prevention gates, it is preferably made of a highly rigid material such as steel or stainless steel.

[0023] When the lid 22 is opened by the pressure of the liquid L flowing through the pipe P, an angle θ is formed between the inner surface 221 of the lid 22 and the opening 212 of the main body 21, as shown in Figure 1. More specifically, an angle θ is formed between the inner surface 221 of the lid 22 when liquid L is flowing through the pipe P and the inner surface 221 of the lid 22 when liquid L is not flowing through the pipe P (hereinafter also referred to as the "initial state"). In the initial state, the lid 22 does not necessarily have to be aligned with the vertical direction, and may form an angle λ with the vertical direction, as shown in Figure 2. The angle λ is, for example, approximately 0° to 30°, preferably 0° to 20°, and more preferably 0° to 15°. Specifically, for example, it is 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30°, and may also be within the range of any two of the values ​​exemplified here.

[0024] (Openness sensor) The openness sensor 3 acquires openness information indicating the degree of openness of the lid 22. In this embodiment, the openness sensor 3 is a three-dimensional (three-axis) acceleration sensor that operates in conjunction with the lid 22. The type of three-dimensional acceleration sensor is not particularly limited and examples include piezoresistive type, piezoelectric element type, strain gauge type, etc.

[0025] Specifically, the openness sensor 3 is attached (fixed) to the lid 22. In the examples shown in Figures 1 and 2, the openness sensor 3 is attached to the outer surface of the lid 22, but it is sufficient that the openness information can be obtained without interfering with the operation of the lid 22, and it may be attached to the side, inner surface, bottom surface, top surface, etc. of the lid 22. In this embodiment, the openness sensor 3 acquires and outputs acceleration in three axes (X axis, Y axis, and Z axis) as openness information.

[0026] (Connection mechanism) The openness sensor 3 is connected to the recording device 5 via a connection mechanism 4. The connection mechanism 4 is, for example, a wire, which transmits each piece of information output by the openness sensor 3 to the recording device 5.

[0027] The connection mechanism 4 has sufficient flexibility and is arranged with some play. This minimizes the influence of the connection mechanism 4 on the opening and closing operation of the lid 22. The connection mechanism 4 is preferably a robot cable, which allows it to bend flexibly in accordance with the opening and closing operation of the lid 22, thus minimizing its impact on the operation. In other words, the measurement accuracy of the flow rate measurement system 1 can be maintained at a high level. The number of cores in the connection mechanism 4 is not particularly limited, as long as it can transmit the necessary information between the openness sensor 3 and the recording device 5. For example, the number of cores in the connection mechanism 4 may be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12. The connection mechanism 4 may also include multiple cables.

[0028] The connection mechanism 4 is fixed to the main body 21 or the end of the piping P on the main body 21 side by a fixing member 4a. Figures 1 and 2 show an example in which the connection mechanism 4 is fixed to the main body 21. Specifically, the fixing member 4a fixes the connection mechanism 4 to the main body 21 or piping P at a predetermined length from the end of the connection mechanism 4 on the openness sensor 3 side. The predetermined length is, for example, the shortest length at which the connection mechanism 4 does not obstruct the opening of the lid 22 that forms an angle θ within a predetermined range. The predetermined range is, for example, approximately 0° to 90°. This prevents or suppresses the load across the entire length of the connection mechanism 4 between the openness sensor 3 and the recording device 5 from being applied to the cover 22, and further improves the measurement accuracy of the flow rate measurement system 1. The fixing member 4a only needs to be able to fix the connection mechanism 4 to the main body 21 or the piping P, and for example, a band, adhesive tape, adhesive, etc. made of a hard material or an elastic material can be used as the fixing member 4a. Furthermore, it is preferable that the connection portion between the connection mechanism 4, the openness sensor 3, and the recording device 5 be liquid-tight with a waterproof material such as a sealing agent.

[0029] (Recording device) The recording device 5 receives and records each piece of information output from the openness sensor 3 via the connection mechanism 4. In this embodiment, the recording device 5 is, for example, a data logger, memory recorder, or oscilloscope. In particular, the recording device 5 is preferably a data logger, in which case the recorded data can be digitized and recorded with high precision.

[0030] As shown in Figures 1 and 2, the recording device 5 is provided separately from the openness sensor 3, which reduces the weight of the equipment attached to the flap gate 2's cover 22. Therefore, for example, in areas with relatively low flow rates, such as underground drainage systems in farmland (e.g., 0 m 3 / h or more 10m 3 Even when the flow rate is approximately 0.7 / h or less, the lid 22 is more easily opened by the pressure of the liquid L flowing through the pipe P, allowing for more reliable flow rate measurement.

[0031] As shown in Figure 3, the recording device 5 includes a communication unit 51, a storage unit 52, and a processor 53, and these components are electrically connected within the recording device 5 via a communication bus 50. The communication unit 51 is configured to transmit various electrical signals from the recording device 5 to external components. The communication unit 51 is also configured to receive various electrical signals from external components to the recording device 5. Specifically, the communication unit 51 receives openness information output from the openness sensor 3. Furthermore, the communication unit 51 transmits control signals from the processor 53 to the openness sensor 3. The operation of the openness sensor 3 is controlled based on these control signals.

[0032] The memory unit 52 stores various information as defined above. This can be done, for example, as a storage device such as a solid-state drive (SSD) that stores various programs related to the open-degree sensor 3 executed by the processor 53, or as memory such as random-access memory (RAM) that stores temporarily necessary information (arguments, arrays, etc.) related to program calculations. The memory unit 52 stores various programs and variables related to the open-degree sensor 3 executed by the processor 53. In particular, in this embodiment, the storage unit 52 stores the openness information output from the openness sensor 3. When the recording device 5 is a data logger, the storage unit 52 has multiple channels. The recording device 5 then records the information contained in the openness information (for example, acceleration information in the X, Y, and Z axes) as a digital signal in each channel.

[0033] The processor 53 is, for example, a central processing unit (CPU) not shown. The processor 53 realizes various functions related to the openness sensor 3 by reading predetermined programs stored in the memory unit 52. That is, information processing by software stored in the memory unit 52 is concretely realized by the processor 53, which is an example of hardware, and can be executed as each functional unit included in the processor 53. Note that the processor 53 is not limited to a single unit, and may be implemented with multiple processors 53 for each function, or a combination thereof.

[0034] Specifically, the processor 53 controls the measurement interval of various information from the openness sensor 3 (for example, every 1 second, every 2 seconds, every 5 seconds, every 10 seconds, etc.), communication via the communication unit 51, digitization of various information output from the openness sensor 3, and storage of the digitized information in the storage unit 52.

[0035] (Liquid level sensor) As shown in Figure 1, the flow rate measurement system 1 further includes a liquid level sensor 6. The liquid level sensor 6 is a level sensor such as a float type, microwave type, or hydraulic (pressure) type.

[0036] The liquid level sensor 6 then acquires the height of the liquid level S as liquid level information in the vicinity of the flap gate 2. As will be described in detail later, the liquid level information output by the liquid level sensor 6 is used for comparison with information regarding the installation height of the flap gate 2. Here, since the installation height of the flap gate 2 is fixed, the liquid level information essentially indicates the height of the liquid level S of the liquid L (hereinafter also referred to as "surrounding liquid L'") surrounding the flap gate 2 relative to the flap gate 2.

[0037] As will be described later, even if the flow rate of the liquid L flowing inside the pipe P is the same, the angle θ at which the flap gate 2's cover 22 opens in response to the pressure of the liquid L is affected by whether or not the flap gate 2 is submerged in the liquid L. By using the liquid level sensor 6, the flow rate can be calculated using an appropriate calculation method according to the height of the liquid level S.

[0038] Specifically, liquid level information is used to determine whether or not the flap gate 2 is submerged in the surrounding liquid L'. Therefore, the liquid level information essentially indicates whether or not the flap gate 2 is submerged in the liquid L surrounding the flap gate 2 (hereinafter also referred to as "surrounding liquid L'").

[0039] Here, we will refer to Figure 4 for further explanation. Figure 4 schematically shows the non-submerged state (Figure 4(a)), where the flap gate is not submerged in the liquid, the semi-submerged state (Figure 4(b)), where the flap gate is partially submerged in the liquid, and the submerged state (Figure 4(c)), where the flap gate 2 is submerged in the liquid L. The non-submerged state is, as shown in Figure 4(a), when the flap gate 2 is completely exposed from the liquid L. In other words, the surrounding liquid L' does not apply pressure to the lid 22 and therefore does not affect the opening and closing operation of the lid 22. The semi-submerged state is, as shown in Figure 4(b), when a part of the flap gate 2 is submerged in the surrounding liquid L'. In the semi-submerged state, the degree to which the surrounding liquid L' affects the opening and closing operation of the lid 22 may vary depending on the height of the liquid level S. The submerged state is, as shown in Figure 4(c), when the flap gate 2 is completely submerged in the liquid L. In the submerged state, pressure from the surrounding liquid L' is applied to the entire outside of the lid 22.

[0040] Non-Patent Document 1 measured the liquid flow rate under limited conditions, specifically when the flap gate was partially submerged (for example, as shown in Figure 4(b)). In particular, when the pipe diameter is relatively small, such as in underground drainage systems in farmland (for example, an inner diameter of approximately 40 mm to 150 mm), the conditions for achieving a partially submerged state are extremely limited, making it impractical to apply the method described in Non-Patent Document 1. Furthermore, Non-Patent Document 1 required obtaining two variable parameters: the degree of opening of the cover and the height from the bottom of the pipe to the water surface, making the measurement of these parameters and the calculation of the flow rate complicated.

[0041] Therefore, after diligent investigation, the inventors found that a significant correlation can be obtained between the flow rate of liquid L and the angle θ of the flap gate 2 in both the non-submerged state (see Figure 4(a)) and the submerged state (see Figure 4(c)). In other words, the inventors found that the flow rate measurement system 1 can measure the flow rate of liquid L flowing through pipe P in both the non-submerged and submerged states. To put it another way, the flow rate measurement system 1 can ensure sufficient opportunities to measure the flow rate of liquid L flowing through pipe P. Furthermore, the inventors confirmed that even if the height of the liquid surface S (water depth) fluctuates in the submerged state, the influence of the surrounding liquid L' on the angle θ is negligible.

[0042] Furthermore, the inventors discovered that, based on the correlations they found, the flow rate of liquid L can be determined from the angle θ with sufficient accuracy (for example, with an error of approximately 0% to 20%) by distinguishing between submerged and non-submerged states. In other words, the flow rate measurement system 1 can measure the flow rate based on the minimum variable parameter of angle θ, thereby preventing the complexity of parameter acquisition and flow rate calculation. That is, the flow rate of liquid L is measured based on liquid level information. The measurement method using liquid level information will be described in detail later.

[0043] In this embodiment, the liquid level sensor 6 further incorporates a recording device (not shown) or is connected to a recording device (not shown). The configuration of this recording device is the same as that described for the recording device 5. However, the liquid level sensor 6 is not limited to this configuration, and like the openness sensor 3, it may delegate functions such as control and recording to the recording device 5. In other words, the liquid level sensor 6 may be connected to the recording device 5, and the recording device 5 may record liquid level information and control the various functions of the liquid level sensor 6.

[0044] (Information processing device) The flow rate measurement system 1 further comprises an information processing device 7. As shown in Figure 3, the information processing device 7 (flow rate measurement system 1) has a communication unit 71, a storage unit 72, and a processor 73, and these components are electrically connected within the information processing device 7 via a communication bus 70.

[0045] The communication unit 71 is configured to transmit various electrical signals from the information processing device 7 to external components. The communication unit 71 is also configured to receive various electrical signals from external components to the information processing device 7. While wired communication methods such as USB, IEEE1394, Thunderbolt®, and wired LAN network communication are preferred for the information processing device 7, wireless LAN network communication, mobile communication such as 3G / LTE / 5G, and Bluetooth® communication may be included as needed. In other words, it is more preferable to implement the system as a collection of these multiple communication methods.

[0046] In this embodiment, the communication unit 71 receives digitized openness information from the recording device 5 and liquid level information from the liquid level sensor 6. In this case, a storage medium such as a removable flash memory may function as the storage unit for the recording device 5 and the liquid level sensor 6, and this information can be received by connecting this storage medium to the communication unit 71.

[0047] The memory unit 72 stores various types of information as defined above. This can be done, for example, as a storage device such as a solid-state drive (SSD) that stores various programs related to the information processing device 7 executed by the processor 73, or as memory such as random access memory (RAM) that stores temporarily necessary information (arguments, arrays, etc.) related to program calculations. A combination of these may also be used. In particular, the memory unit 72 stores the degree of opening and liquid level information received by the communication unit 71, as well as information regarding the installation height of the flap gate 2. The memory unit 72 also stores reference information regarding the relationship between the degree of opening of the lid 22 and the flow rate of the liquid L passing through the flap gate 2.

[0048] The processor 73 performs processing and control of the overall operation related to the information processing device 7. The processor 73 is, for example, a central processing unit (CPU) not shown. The processor 73 realizes various functions related to the information processing device 7 by reading predetermined programs and reference information stored in the memory unit 72. In other words, the information processing by software stored in the memory unit 72 is concretely realized by the processor 73, which is an example of hardware. The processor 73 is configured to measure the flow rate of liquid based on the degree of openness information and the reference information stored in the memory unit 72.

[0049] [Processor Functional Configuration] Next, the functional configuration of the processor 73 of the information processing device 7 will be described. As mentioned above, the information processing performed by the software stored in the memory unit 72 is concretely realized by the processor 73, which is an example of hardware, and can be executed as each functional unit included in the processor 73.

[0050] Figure 5 is a block diagram showing the functions realized by the processor and other components in the information processing device. Specifically, the processor 73 includes an acquisition unit 731, a conversion unit 732, an input processing unit 733, and an output unit 734. The acquisition unit 731 is configured to acquire various information obtained from an external source via the communication unit 71 or stored in the storage unit 72 in advance as an acquisition step. For example, the acquisition unit 731 acquires various information stored in the storage unit 72, namely, openness information output from the openness sensor 3, liquid level information output from the liquid level sensor 6, reference information, and information such as the installation height of the flap gate 2.

[0051] The conversion unit 732 is configured to perform predetermined calculations on various pieces of information acquired by the acquisition unit 731 as a conversion step, thereby converting the information. For example, the conversion unit 732 converts the openness information acquired by the acquisition unit 731 into the angle θ between the main body 21 and the lid 22. The input processing unit 733 is configured to input an angle θ to the reference information stored in the storage unit 72 as an input processing step. The output unit 734 is configured to output various information as an output step. Specifically, the output unit 734 can output the flow rate of liquid L measured based on reference information.

[0052] [Flow rate measurement method] Next, with reference to Figure 6, a method for measuring the flow rate of liquid L using the flow rate measurement system 1 will be described. The order of the processes can be rearranged as appropriate, multiple processes may be executed simultaneously, and some processes may be omitted. Furthermore, as mentioned above, various forms of reference information are conceivable, but in the following flow rate measurement method, the reference information will be described as, for example, a predetermined function that has been linearly approximated. Figure 6 is an activity diagram showing an overview of the processes performed using the flow rate measurement system.

[0053] First, liquid level information output from the liquid level sensor 6 is acquired (activity A001). In this embodiment, the liquid level information output by the liquid level sensor 6 is the height of the liquid level S of the surrounding liquid L'.

[0054] Next, based on the liquid level information and the information regarding the installation height of the flap gate 2, which is pre-stored in the memory unit 72, it is determined whether or not the flap gate 2 is submerged in the liquid L. Here, as mentioned above, since the installation height of the flap gate 2 is a fixed value, the liquid level information essentially indicates the height of the liquid level S of the liquid L (surrounding liquid L') surrounding the flap gate 2 relative to the flap gate 2. More precisely, the liquid level information essentially indicates whether or not the flap gate 2 is submerged in the liquid L surrounding the flap gate 2.

[0055] If the determination result is a non-submerged state as shown in Figure 4(a), the first reference information is selected (Activity A002). If the determination result is a submerged state as shown in Figure 4(c), the second reference information is selected (Activity A003). If the determination result is a semi-submerged state as shown in Figure 4(b), this method is not applicable, and the process returns to the beginning of the activity. Thus, this flow rate measurement method avoids complexity in measurement and calculation by excluding the semi-submerged state, where conditions can change rapidly. Furthermore, because this flow rate measurement method excludes the semi-submerged state, where unexpected situations may occur, it is possible to ensure a reasonable level of accuracy in the final obtained flow rate.

[0056] As described above, there is a significant correlation between the flow rate of liquid L flowing through pipe P and the angle θ of flap gate 2 in both the submerged and non-submerged states. Specifically, there is a positive correlation between the flow rate of liquid L and the angle θ. On the other hand, according to the inventors' findings, the slope of the line representing this correlation differs between the submerged and non-submerged states. Therefore, the reference information is selected based on whether the state is submerged or non-submerged.

[0057] The first reference information selected in Activity A002 is information for deriving the flow rate of liquid L from the angle θ in the non-submerged state. The second reference information selected in Activity A003 is information for deriving the flow rate of liquid L from the angle θ in the submerged state. In other words, the reference information relates to the relationship between the degree of opening and the flow rate of liquid passing through the flap gate. The reference information used to measure the liquid flow rate is changed depending on whether the flap gate is submerged or not. By adopting a clear and simple distinction between submerged and unsubmerged states, the flow rate of liquid L flowing through pipe P can be easily measured. Furthermore, since errors in judgment are easily prevented, measurement accuracy is improved.

[0058] In addition, in parallel with the activities from acquiring liquid level information to selecting reference information, openness information is acquired (activity A004). As mentioned above, openness information indicates the degree of openness of the flap gate 2's cover 22 and is the information output to the openness sensor 3.

[0059] Here, the time when the liquid level information for activity A001 is acquired by the liquid level sensor 6 and the time when the openness information for activity A004 is acquired by the openness sensor 3 generally coincide. These times may coincide perfectly, or there may be a gap of, for example, a few seconds to an hour, and it is particularly preferable that the gap be between 0 seconds and 10 minutes. In particular, if the height of the liquid level S does not change rapidly, the submerged or non-submerged state does not change easily, so a large gap between these times is acceptable.

[0060] Next, based on the degree of opening information, the angle θ, which is the degree of opening of the lid 22, is calculated (Activity A005). The angle θ can be calculated based on the following formula.

number

[0061] Further explanation will be given here with reference to Figures 7(a) and 7(b). Figure 7 is a schematic diagram showing examples of installation variations of the flow measurement system (Figures 7(a) and 7(b)). Ideally, the flap gate 2 is preferably installed so that the cover 22 (connecting body 23) rotates around an axis parallel to the horizontal direction H, in other words, rotates along a plane perpendicular to the vertical direction V, as shown in Figure 7(a). However, especially in outdoor work, it is difficult to install the flap gate 2 exactly as shown in Figure 7(a), and it is also difficult to verify this.

[0062] In the flow measurement method using the flow measurement system 1 of this disclosure, as shown in Figure 7(b), it is also permissible for the cover 22 (connecting body 23) to rotate around an axis parallel to direction H', in other words, to rotate along a plane perpendicular to direction V'. Here, directions H' and V' are directions rotated by an angle φ with respect to the horizontal direction H and the vertical direction V, respectively. The angle φ is preferably about -20° to 20°, and more preferably about -15° to 15°. The angle θ is obtained by the dot product of the acceleration g when the lid 22 is open due to the pressure of the liquid L and the initial acceleration g0, thereby calibrating the angle θ using the initial acceleration g0. In this way, by obtaining the angle θ as a relative value, the influence of the accuracy of the installation of the flap gate 2 on flow rate measurement can be reduced. That is, as shown in Figure 7(b), even if the flap gate 2 is installed in a slightly rotated position, the flow rate can be measured appropriately. Furthermore, if the angle φ exceeds the range described above, it can be easily noticed and corrected by visual inspection during installation. In other words, there is no need to use a spirit level or protractor when installing the flap gate 2. However, the installation angle of the flap gate 2 (and piping P) in the direction of liquid L flow should preferably be close to horizontal (for example, between -5° and 5° relative to the horizontal direction), and it is preferable to install the flap gate 2 while checking the angle with a spirit level or similar instrument. This further improves the accuracy of measuring the flow rate of liquid L.

[0063] Then, based on the calculated angle θ (openness information) and the reference information selected based on the liquid level information, the flow rate of liquid L flowing through pipe P is calculated (measured) (Activity A006). Specifically, for example, the calculated angle θ is substituted (input) into an equation (reference information) that shows the correlation between the flow rate of liquid L flowing through pipe P and the angle θ. Thus, the flow rate of the liquid L flowing through the pipe P can be obtained using only the relative angle θ between the position of the lid 22 when it is open due to the pressure of the liquid L and the position of the lid 22 in the initial state when no liquid L is flowing, as the variable parameter. In this manner, the flow rate of liquid L flowing through pipe P is obtained (measured).

[0064] The flow rate measurement method described herein can be applied to various uses and can be modified in various ways depending on the purpose. For example, the activities from acquiring liquid level information (Activity A001) to selecting reference information (Activities A002, A003) and the activities from acquiring openness information (Activity A004) to calculating the angle θ (Activity A005) do not have to be performed simultaneously; one may be performed first.

[0065] Furthermore, for example, if the flap gate 2 of the flow rate measurement system 1 is installed at the drainage outlet of an underground drainage system (underground drainage facility) in farmland, the flow rate measurement method may also acquire rainfall. Here, as a method for acquiring rainfall, equipment capable of actually acquiring rainfall, such as a rain gauge, may be installed around the installation site of the flap gate 2 or in the area including the installation site, and the rainfall may be acquired from the internet or the like. This acquisition of rainfall may be performed, for example, simultaneously with activities A001 to A005, or before or after them. Also, the time when the acquired rainfall is actually measured generally coincides with the time when the liquid level information for activity A001 is acquired by the liquid level sensor 6 and the time when the openness information for activity A004 is acquired by the openness sensor 3. These times may also coincide perfectly, or there may be a gap of, for example, several seconds to 1 hour, and it is particularly preferable that the gap be between 0 seconds and 10 minutes.

[0066] In this case, after calculating the flow rate in Activity A006 (in the measurement step), the drainage function of the underground drainage system may be further diagnosed based on the measured flow rate and the amount of rainfall. That is, by determining whether the amount of water (liquid L) that should be drained from the underground drainage system is being discharged in light of the amount of rainfall, it is possible to determine whether the underground drainage system is functioning properly. This method allows for easy diagnosis of the drainage function of underground drains, thus reducing the risk of unexpected damage such as waterlogging caused by neglecting such diagnoses. Furthermore, because the flow rate measurement system 1 is used, the drainage function of underground drains can be diagnosed at a low cost. In other words, the flow rate measurement system 1 can also function as a drainage function diagnostic system. Moreover, the flow rate measurement method of this disclosure can also be used as a drainage function diagnostic method.

[0067] Furthermore, according to the inventors' experimental results, it was confirmed that the flow rate measurement system 1 and flow rate measurement method of this disclosure can achieve sufficient accuracy within a practical range when measuring the flow rate of underground drainage systems in agricultural land. Specifically, for liquids with a specific flow rate of at least 0 mm / h to 4 mm / h, which is the amount of liquid that underground drainage systems in agricultural land typically discharge, it was possible to measure the flow rate with an error (mean squared error rate) of about 20% or less.

[0068] Furthermore, part or all of the flow rate measurement method may be implemented as a distributable program. This program causes a computer to perform each step (activity) of the flow rate measurement method. The program may be recorded in, for example, the memory unit 72, or stored in the memory unit 52, or it may be stored on a server (not shown) and implemented as a cloud service, making it available to a large number of users via a network.

[0069] Furthermore, some or all of the flow rate measurement method may be performed manually. For example, the information to be acquired may be recorded in a notebook, and the flow rate may be calculated by substituting the angle θ into the reference information in the notebook or calculation software. According to the flow rate measurement system 1 and flow rate measurement method described above, the flow rate of liquid L flowing through pipe P can be measured easily and inexpensively.

[0070] [Differentiation] The following describes some variations of the flow rate measurement system 1 described above. The embodiments described above and the following descriptions are interchangeable.

[0071] The openness sensor 3 is not limited to a 3D accelerometer and only needs to be able to acquire openness information. For example, the openness sensor 3 may be a 1D (1-axis) or 2D (2-axis) accelerometer. Alternatively, the openness sensor 3 may be a camera, which may photograph the flap gate 2 from a direction that can recognize the angle θ, such as from the side. In the flow measurement method, video or time-lapse images captured by the camera may be acquired, and the angle θ may be measured manually or automatically by an image processing program using image processing. Alternatively, the acquired video may be input to a learning model that has learned the openness and angle as training data, and the angle θ may be output. However, it is preferable that the openness sensor 3 is a 3D accelerometer, in which case the angle θ can be acquired with greater accuracy.

[0072] The openness sensor 3 and the recording device 5 do not need to be configured as separate units; they may be integrated. For example, the openness sensor 3 may have a built-in recording device 5. If the openness sensor 3 is an acceleration sensor, for example, an acceleration sensor with a built-in data logger can be fixed to the cover 22 of the flap gate 2. Also, if the openness sensor 3 is a camera, the flap gate 2 can be photographed with a camera with a built-in memory unit. In this way, if the openness sensor 3 and the recording device 5 are integrated, there is no need to provide a connection mechanism 4, and the connection between devices around the flap gate 2 can be simplified. Therefore, an improvement in the waterproof performance of the flow rate measurement system 1 can be expected.

[0073] Instead of the openness sensor 3 and the recording device 5 being connected by the connection mechanism 4, they may be connected by a wireless connection such as Bluetooth®, wireless USB, or Wi-Fi. Furthermore, the openness sensor 3 may be controlled by the recording device 5 via a wireless connection, or instead of being controlled by the recording device 5, it may have a built-in processor and be controlled by that processor. The openness sensor 3 may then transmit various information to the recording device 5 via a wireless connection. In this case as well, the connections between devices around the flap gate 2 can be simplified.

[0074] The liquid level sensor 6 is not limited to a level sensor; it just needs to be able to acquire liquid level information. For example, the liquid level sensor 6 could be a camera, and it could acquire video or images as liquid level information such that the flap gate 2 and the liquid level S are within its field of view. In this case, it is possible to determine whether or not the flap gate 2 is submerged in the liquid L based solely on the information acquired by the liquid level sensor 6, so the storage unit 72 of the information processing device 7 does not need to store information regarding the installation height of the flap gate 2. Also, depending on the installation angle, one camera can perform the functions of both the openness sensor 3 and the liquid level sensor 6.

[0075] Furthermore, the installation of the liquid level sensor 6 may be omitted. In this case, it is advisable for the user to visually confirm whether the flap gate 2 is submerged in liquid at the location where the flap gate 2 is installed beforehand. Then, for example, by omitting activity A001 in the activity diagram of Figure 6, the flow rate of liquid L can be measured by obtaining whether it is submerged or not, or by acquiring (selecting or inputting by the user) reference information to be read. Furthermore, information regarding the installation height of the flap gate 2 does not necessarily have to be pre-stored in the storage unit 72 of the information processing device 7. For example, the installation height selected or entered by the user may be obtained at the timing of activity A001 in Figure 6.

[0076] If it is known in advance that the flap gate 2 is always either submerged or not submerged, the installation of the liquid level sensor 6 may, of course, be omitted. In this case, activities A001 to A003 in the activity diagram of Figure 6 can be omitted. Then, in activity A006, if the flap gate 2 is always submerged, the first reference information is referred to, and if the flap gate 2 is always not submerged, the second reference information is referred to.

[0077] The recording device 5 and the information processing device 7 do not necessarily have to be provided as separate units; they may be provided as a single unit. For example, the recording device 5 provided near the flap gate 2 may have the information processing device 7 built into it. Conversely, the information processing device 7 may have the recording device 5 built into it, and the openness information acquired by the openness sensor 3 may be stored in the openness sensor 3 itself.

[0078] Furthermore, the information acquired by the openness sensor 3 or the liquid level sensor 6 may be directly transmitted to the information processing device 7 by wired or wireless communication means. In this case, the recording device 5 can be omitted. The acquired information may be transmitted to the information processing device 7 each time it is acquired, or it may be transmitted to the information processing device 7 each time information is acquired multiple times.

[0079] Furthermore, if the flow rate measurement method is performed manually rather than by a program, the flow rate measurement system 1 does not need to have an information processing device 7.

[0080] The openness information may be calculated in advance as an angle θ before the flow rate measurement method is performed. Also, the liquid level information may be converted in advance as information indicating either a non-submerged, partially submerged, or submerged state before the flow rate measurement method is performed. In this case, the flow rate measurement method does not need to calculate the angle θ (activity A005) or determine whether the state is non-submerged, partially submerged, or submerged. The liquid level information may be further converted into one of the following: first reference information (in the case of a non-submerged state), information indicating invalidity (in the case of a partially submerged state), or second reference information (in the case of a submerged state).

[0081] In the embodiments described above, a predetermined function linearly approximated is used as an example of reference information, and in particular, the flow rate of liquid L is measured by selecting either the first or second reference information. However, the flow rate measurement method of this disclosure is not limited thereto. For example, the reference information may be a trained model (AI) that outputs a flow rate when input with openness information and liquid level information, and the flow rate of liquid L may be measured using such a trained model. Furthermore, the inventors have found a significant correlation between flow rate and angle θ, which indicates the high reliability of this trained model.

[0082] Furthermore, the scope to which the trained model can be applied is not limited to this. For example, if a flap gate 2 is installed in a drainage system in farmland, in addition to the openness information and liquid level information, a trained model can be used to determine (output) whether the discharge rate of liquid L from the drainage system is appropriate, that is, to diagnose (output) whether the drainage system is functioning properly, by inputting rainfall amount. This rainfall amount can be input as the rainfall amount itself, or the location information of the area where the flap gate 2 is installed can be input, and the rainfall amount for the automatically input area can be retrieved from the internet or other sources.

[0083] Furthermore, they may be provided in the following embodiments.

[0084] (1) A system for measuring the flow rate of a liquid, comprising a flap gate and an openness sensor, wherein the flap gate has a lid and is configured to open the lid in response to the pressure of the liquid, the openness sensor acquires openness information indicating the degree of openness of the lid, and the flow rate of the liquid is measured based on the openness information.

[0085] (2) The system described in (1) above, further comprising a liquid level sensor, wherein the liquid level sensor acquires liquid level information indicating the height of the liquid level of the liquid present around the flap gate relative to the flap gate.

[0086] (3) In the system described in (2) above, the liquid level information indicates whether or not the flap gate is submerged in the liquid present around the flap gate.

[0087] (4) In the system described in (2) or (3) above, the flow rate of the liquid is measured based on the liquid level information.

[0088] (5) A system in which, in any one of (1) to (4) above, the openness sensor is a three-dimensional acceleration sensor attached to the lid.

[0089] (6) In the system described in any one of (1) to (5) above, the flap gate is installed at the drainage outlet of an underground drainage facility for farmland.

[0090] (7) A system according to any one of (1) to (6) above, further comprising a processor, wherein the processor is configured to measure the flow rate of the liquid based on reference information relating to the relationship between the degree of opening and the flow rate of the liquid passing through the flap gate.

[0091] (8) A method for measuring the flow rate of a liquid, comprising the steps of: acquiring openness information indicating the degree of opening of the lid of a flap gate; and measuring the flow rate of the liquid based on the openness information and reference information relating to the relationship between the degree of opening and the flow rate of the liquid passing through the flap gate.

[0092] (9) The method according to (8) above, further comprising the step of acquiring liquid level information indicating the height of the liquid level of the liquid present around the flap gate relative to the flap gate, wherein in the measurement step, the flow rate of the liquid is measured based on the liquid level information.

[0093] (10) The method according to (9) above, wherein the liquid level information indicates whether or not the flap gate is submerged in the liquid present around the flap gate.

[0094] (11) The method according to (10) above, wherein in the measurement step, the reference information used for measuring the flow rate of the liquid is changed depending on whether or not the flap gate is submerged.

[0095] (12) The method according to any one of (8) to (11) above, wherein the flap gate is installed at the drainage outlet of an underground drainage facility for farmland.

[0096] (13) A method according to (12) above, further comprising the step of obtaining rainfall, wherein the measuring step further diagnoses the drainage function of the underground drainage facility based on the measured flow rate and the rainfall. Of course, this is not always the case.

[0097] As previously described, various embodiments of the present invention have been explained, but these are merely examples and do not limit the scope of the invention in any way. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0098] 1: Flow measurement system 10:Error 2: Flap gate 21: Main unit 211: Fitting part 212: Opening 22: Lid 221: Inner self 23: Connector 3: Openness sensor 4: Connection mechanism 4a: Fixing member 5: Recording device 50: Communications bus 51: Communications Department 52: Storage section 53: Processor 6: Liquid level sensor 7: Information Processing Device 70: Communications bus 71: Communications Department 72: Storage section 73: Processor 731: Acquisition Department 732: Conversion section 733: Input Processing Unit 734: Output section H:Horizontal direction L:Liquid L': Ambient liquid P: Piping P1: Drain port S:Liquid level V: Vertical direction θ: angle λ :Angle φ: Angle

Claims

1. A system for measuring the flow rate of a liquid, Equipped with a flap gate and an openness sensor, The flap gate has a lid and is configured to open the lid in response to the pressure of the liquid. The openness sensor acquires openness information indicating the degree of openness of the lid, Based on the aforementioned openness information, the flow rate of the liquid is measured. system.

2. In the system described in claim 1, It further includes a liquid level sensor, The liquid level sensor acquires liquid level information indicating the height of the liquid level surrounding the flap gate relative to the flap gate. system.

3. In the system described in claim 2, The liquid level information indicates whether or not the flap gate is submerged in the liquid surrounding the flap gate. system.

4. In the system described in claim 2, The flow rate of the aforementioned liquid is measured based on the aforementioned liquid level information. system.

5. In the system described in claim 1, The aforementioned openness sensor is a three-dimensional acceleration sensor attached to the cover. system.

6. In the system described in claim 1, The aforementioned flap gate is installed at the drainage outlet of the underground drainage system for agricultural land. system.

7. In the system according to any one of claims 1 to 6, Equipped with an additional processor, The processor is configured to measure the flow rate of the liquid based on reference information relating to the degree of opening and the flow rate of the liquid passing through the flap gate. system.

8. A method for measuring the flow rate of a liquid, A step to obtain information indicating the degree of opening of the flap gate cover, The method includes the step of measuring the flow rate of the liquid based on the aforementioned openness information and reference information relating to the relationship between the degree of openness and the flow rate of the liquid passing through the flap gate. method.

9. In the method according to claim 8, The method further includes the step of acquiring liquid level information indicating the height of the liquid level of the liquid present around the flap gate relative to the flap gate, In the measurement step, the flow rate of the liquid is measured based on the liquid level information. method.

10. In the method according to claim 9, The liquid level information indicates whether the flap gate is submerged in the liquid surrounding it. method.

11. In the method according to claim 10, In the measurement step, the reference information used to measure the flow rate of the liquid is changed depending on whether the flap gate is submerged or not. method.

12. In the method according to any one of claims 8 to 11, The aforementioned flap gate is installed at the drainage outlet of the underground drainage system for agricultural land. method.

13. In the method according to claim 12, Furthermore, it includes a step of obtaining rainfall amount, In the measurement step, the drainage function of the underground drainage facility is further diagnosed based on the measured flow rate and the amount of rainfall. method.

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