Time difference method ultrasonic wave open channel water level and flow measuring device and measuring method thereof

Abstract

The present application relates to the technical fields of open channel flow measurement, and is an open channel water level and flow measuring device and method based on time difference method, comprising a downstream ultrasonic transducer, an upstream ultrasonic transducer, two brackets and a controller, the downstream ultrasonic transducer and the upstream ultrasonic transducer are respectively installed on the two brackets in one-to-one correspondence through a set of adjusting mechanisms to adjust their height and angle in the vertical plane, and the downstream ultrasonic transducer, the upstream ultrasonic transducer and the two sets of adjusting mechanisms are electrically connected with the controller. The present application has a reasonable structure, and can achieve the purpose of measuring the open channel water level height through the downstream ultrasonic transducer and the upstream ultrasonic transducer, without using a water level gauge to measure the open channel water level height, thereby reducing the equipment cost. In addition, the controller can not only control the height of the downstream ultrasonic transducer and the upstream ultrasonic transducer, but also control the angle thereof, thereby being suitable for the measurement of water flow rate at different water level heights of the open channel, and having good flexibility.

Description

Technical Field

[0001] This invention relates to the field of open channel flow measurement technology, and is a time-difference ultrasonic open channel water level and flow measurement device and its measurement method. Background Technology

[0002] Water measurement is a crucial aspect of irrigation management. As a fundamental means of water-saving irrigation and scientific management, water measurement in irrigation districts is receiving increasing attention. Scientific management of irrigation districts requires automated and digitalized water measurement. Ultrasonic flow meters offer significant advantages in fluid measurement. Ultrasonic flow measurement technology overcomes many limitations of traditional flow measurement methods, such as low accuracy, inability to continuously record the process in real time, high labor intensity, and cumbersome data statistics. It possesses unique advantages. In recent years, with the accelerated pace of information technology construction in large irrigation districts, the use of ultrasonic flow meters to measure the flow rate in open channels and achieve real-time monitoring of water measurement in irrigation districts has been increasingly applied in many places.

[0003] However, the ultrasonic probes in current ultrasonic flow meters are all in fixed positions, which cannot adapt to changes in water level and have poor flexibility in use. In addition, a special water level meter is often required to measure the water level in open channels, resulting in high costs for the entire set of equipment.

[0004] Chinese invention patent application CN201810039693.3 discloses a multi-channel ultrasonic open channel flow meter, which includes a support rod, an ultrasonic probe bracket, a ground wire, and an underground shielded cable. The support rod is connected to the mains power supply via the ground wire, and the support rod is connected to the ultrasonic probe bracket via the underground shielded cable. The support rod is fixed to the riverbank by a support rod base. A water level gauge bracket and an antenna bracket are mounted on the support rod. The antenna bracket is equipped with a Beidou antenna and a GPRS antenna. A water level gauge is located at the end of the water level gauge bracket, positioned above the open channel being measured. A control box is located below the water level gauge bracket. A signal indicator light is located at the top of the support rod, and a solar panel is located between the signal indicator light and the antenna bracket. The ultrasonic probe bracket is placed at a 45-degree angle to the bottom of the liquid being measured in the open channel, and an ultrasonic probe is mounted on the ultrasonic probe bracket, arranged on both sides of the ultrasonic probe bracket. In this patent, the position of the ultrasonic probe is fixed, which cannot adapt to changes in water level. In addition, a separate water level gauge is required to measure the water level in the open channel, increasing the operating cost. Summary of the Invention

[0005] This invention provides a time-difference ultrasonic open channel water level and flow measurement device and method, which overcomes the shortcomings of the prior art and can effectively solve the problems of poor flexibility and high equipment cost of existing ultrasonic open channel flow meters.

[0006] One of the technical solutions of this invention is achieved through the following measures: a time-difference ultrasonic open channel water level and flow measurement device, comprising a downstream ultrasonic transducer, a counter-current ultrasonic transducer, two supports, and a controller. The downstream and counter-current ultrasonic transducers are respectively arranged on both sides of the open channel, with the downstream ultrasonic transducer arranged upstream and the counter-current ultrasonic transducer arranged downstream. The downstream and counter-current ultrasonic transducers are located in the same vertical plane to transmit and receive ultrasonic signals accordingly. The downstream and counter-current ultrasonic transducers are respectively mounted on the two supports one-to-one through a set of adjustment mechanisms to adjust their height and angle in the vertical plane. The downstream and counter-current ultrasonic transducers and the two sets of adjustment mechanisms are all electrically connected to the controller.

[0007] The following are further optimizations and / or improvements to one of the above-mentioned inventive solutions:

[0008] The aforementioned adjustment mechanism may include a height adjustment mechanism and an angle adjustment mechanism. The height adjustment mechanism is mounted on the bracket, and the angle adjustment mechanism is mounted on the height adjustment mechanism.

[0009] The height adjustment mechanism may include a lead screw, a lead screw nut, a guide rod, a slider, and a first drive motor. A rotatable lead screw is vertically mounted on a bracket. A guide rod is fixedly mounted on the bracket on both sides of the lead screw. The slider is slidably mounted on the two guide rods. The lead screw nut is fixedly mounted on the slider and fitted onto the lead screw. The top of the lead screw is connected to the output shaft of the first drive motor. The first drive motor is electrically connected to the controller. The angle adjustment mechanism is mounted on the slider.

[0010] The aforementioned angle adjustment mechanism may include a mounting base, a rotating shaft, a first reduction gear, a second reduction gear, and a second drive motor. The mounting base and the slider are fixedly connected together. The rotating shaft is rotatably mounted on the mounting base. The second drive motor is fixedly mounted on the mounting base. The first reduction gear is mounted on the output shaft of the second drive motor. The second reduction gear, which meshes with the first reduction gear, is mounted on the rotating shaft. The second drive motor and the controller are electrically connected. The central axis of the rotating shaft is perpendicular to the vertical plane where the downstream ultrasonic transducer and the upstream ultrasonic transducer are located. One set of adjustment mechanisms has a downstream ultrasonic transducer fixedly mounted on its rotating shaft, and the other set of adjustment mechanisms has a upstream ultrasonic transducer fixedly mounted on its rotating shaft.

[0011] The second technical solution of the present invention is achieved through the following measures: the measurement method of the time-difference ultrasonic open channel water level and flow measurement device includes the following steps:

[0012] S1: Set initial height h0: During initial installation, the downstream ultrasonic transducer and the upstream ultrasonic transducer are located at the same height and face each other. This height is higher than the water level of the open channel. Record the height of the downstream ultrasonic transducer and the upstream ultrasonic transducer from the bottom of the open channel as the initial height h0.

[0013] S2: Calculate the water level height h1 of the open channel: The controller controls the downstream ultrasonic transducer and the upstream ultrasonic transducer to move downstream synchronously, and simultaneously controls the downstream ultrasonic transducer to emit ultrasonic signals and the upstream ultrasonic transducer to receive ultrasonic signals. When the upstream ultrasonic transducer receives the ultrasonic signal emitted by the downstream ultrasonic transducer for the first time, the controller collects the downstream ultrasonic transducer and the upstream ultrasonic transducer's downstream ultrasonic transducer height h2. The controller calculates the water level height h1 of the open channel based on the initial height h0 and the downstream height h2.

[0014] S3: Calculate the angle between the ultrasonic wave propagation direction and the water flow direction and the vertical direction: The controller controls the counter-current ultrasonic transducer to descend to the bottom of the open channel; the controller calculates the angle between the ultrasonic wave propagation direction and the water flow direction when the downstream and counter-current ultrasonic transducers are facing each other, which should be θ1, based on the width b of the open channel and the distance d between the downstream and counter-current ultrasonic transducers along the water flow direction; the controller calculates the angle between the ultrasonic wave propagation direction and the vertical direction when the downstream and counter-current ultrasonic transducers are facing each other, which should be θ2, based on the width b of the open channel, the water level h1 of the open channel and the distance d between the downstream and counter-current ultrasonic transducers along the water flow direction; the controller controls the downstream and counter-current ultrasonic transducers to rotate according to the calculated θ1 and θ2, so that the downstream and counter-current ultrasonic transducers face each other.

[0015] S4: Calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions: The controller controls the downstream ultrasonic transducer to emit ultrasonic signals and the upstream ultrasonic transducer to receive ultrasonic signals, and collects the propagation time t1 of the ultrasonic waves when they propagate downstream; the controller controls the downstream ultrasonic transducer to receive ultrasonic signals and the upstream ultrasonic transducer to emit ultrasonic signals, and collects the propagation time t2 of the ultrasonic waves when they propagate upstream; calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions based on the collected t1 and t2.

[0016] S5: Calculate the flow velocity V of water in the open channel;

[0017] S6: Calculate the flow rate Q of the water in the open channel.

[0018] The third technical solution of the present invention is achieved through the following measures: the measurement method of the time-difference ultrasonic open channel water level and flow measurement device includes the following steps:

[0019] S1: Set initial height h0: During initial installation, the downstream ultrasonic transducer and the upstream ultrasonic transducer are located at the same height and face each other. This height is higher than the water level of the open channel. Record the height of the downstream ultrasonic transducer and the upstream ultrasonic transducer from the bottom of the open channel as the initial height h0.

[0020] S2: Calculate the water level height h1 of the open channel: The controller controls the downstream ultrasonic transducer and the upstream ultrasonic transducer to move down synchronously for the first time, and simultaneously controls the downstream ultrasonic transducer to emit ultrasonic signals and the upstream ultrasonic transducer to receive ultrasonic signals. When the upstream ultrasonic transducer receives the ultrasonic signal emitted by the downstream ultrasonic transducer for the first time, the controller collects the first synchronous downward height h3 of the downstream ultrasonic transducer and the upstream ultrasonic transducer, and calculates the water level height h1 of the open channel based on the initial height h0 and the first synchronous downward height h3.

[0021] S3: Calculate the siltation height h2 of the open channel: The controller calculates the distance L between the downstream and upstream ultrasonic transducers based on the width b of the open channel and the distance d between the downstream and upstream ultrasonic transducers along the water flow direction. The controller controls the downstream and upstream ultrasonic transducers to descend synchronously for the second time to a height of h1 / 2. The controller controls the downstream and upstream ultrasonic transducers to rotate downwards to a position where the angle between their orientation and the vertical direction is θ3, and tanθ3=(L / 2) / (h1 / 2). The controller controls the downstream ultrasonic transducer to emit ultrasonic signals and the upstream ultrasonic transducer to receive ultrasonic signals. Then the controller controls the upstream ultrasonic transducer to move upwards. When the upstream ultrasonic transducer receives the ultrasonic signal emitted by the downstream ultrasonic transducer, the controller collects the upward height h4 of the upstream ultrasonic transducer and calculates the siltation height h2 of the open channel based on the upward height h4 of the upstream ultrasonic transducer.

[0022] S4: Calculate the water depth H of the open channel: Calculate the water depth H of the open channel based on the water level height h1 and the siltation height h2 of the open channel;

[0023] S5: Calculate the angle between the propagation direction of the ultrasonic wave and the direction of water flow and the vertical direction: The controller controls the downstream ultrasonic transducer to move upward to a height of h1 and controls the upstream ultrasonic transducer to move downward to a height of h2; the controller calculates the angle between the propagation direction of the ultrasonic wave and the direction of water flow when the downstream and upstream ultrasonic transducers are facing each other, which should be θ1, based on the width b of the open channel and the distance d between the downstream and upstream ultrasonic transducers along the direction of water flow; the controller calculates the angle between the propagation direction of the ultrasonic wave and the vertical direction when the downstream and upstream ultrasonic transducers are facing each other, which should be θ2, based on the width b of the open channel, the water depth H of the open channel, and the distance d between the downstream and upstream ultrasonic transducers along the direction of water flow; the controller controls the downstream and upstream ultrasonic transducers to rotate according to the calculated θ1 and θ2 so that the downstream and upstream ultrasonic transducers face each other.

[0024] S6: Calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions: The controller controls the downstream ultrasonic transducer to emit ultrasonic signals and the upstream ultrasonic transducer to receive ultrasonic signals, and collects the propagation time t1 of the ultrasonic waves when they propagate downstream; the controller controls the downstream ultrasonic transducer to receive ultrasonic signals and the upstream ultrasonic transducer to emit ultrasonic signals, and collects the propagation time t2 of the ultrasonic waves when they propagate upstream; calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions based on the collected t1 and t2.

[0025] S7: Calculate the flow velocity V of water in the open channel;

[0026] S8: Calculate the flow rate Q of water in the open channel.

[0027] This invention has a reasonable structure. It can measure the water level in an open channel by using a downstream ultrasonic transducer and a counter-current ultrasonic transducer, eliminating the need for a separate water level gauge and reducing equipment costs. In addition, the controller can not only control and adjust the height of the downstream and counter-current ultrasonic transducers, but also their angle, making it suitable for measuring the water flow velocity at different water levels in an open channel, and offering good flexibility in use. Attached Figure Description

[0028] Appendix Figure 1 This is a top view of the structure of Embodiment 1 of the present invention.

[0029] Appendix Figure 2 This is a schematic diagram of the support structure in Embodiment 1 of the present invention, in which a downstream ultrasonic transducer is installed.

[0030] Appendix Figure 3 For the appendix Figure 2 A top view of the mounting base.

[0031] Appendix Figure 4 The principle of the measurement methods in embodiments two and three of this invention Figure 1 .

[0032] Appendix Figure 5 The principle of the measurement method in Embodiment 2 of the present invention Figure 2 .

[0033] Appendix Figure 6 The principle of the measurement method in Embodiment 3 of the present invention Figure 2 .

[0034] Appendix Figure 7 The principle of the measurement method in Embodiment 3 of the present invention Figure 3 .

[0035] The codes in the attached diagram are as follows: 1 is the downstream ultrasonic transducer, 2 is the upstream ultrasonic transducer, 3 is the bracket, 4 is the lead screw, 5 is the guide rod, 6 is the slider, 7 is the first drive motor, 8 is the mounting base, 9 is the rotating shaft, 10 is the second reduction gear, 11 is the first reduction gear, and 12 is the second drive motor. Detailed Implementation

[0036] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0037] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0038] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0039] Example 1: As shown in the attached document Figure 1-3 As shown, the time-difference ultrasonic open channel water level and flow measurement device includes a downstream ultrasonic transducer 1, a counter-current ultrasonic transducer 2, two supports 3, and a controller. The downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 are respectively arranged on both sides of the open channel, with the downstream ultrasonic transducer 1 arranged upstream and the counter-current ultrasonic transducer 2 arranged downstream. The downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 are located in the same vertical plane to transmit and receive ultrasonic signals accordingly. The downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 are respectively installed on the two supports 3 one-to-one through a set of adjustment mechanisms to adjust their height and angle in the vertical plane. The downstream ultrasonic transducer 1, the counter-current ultrasonic transducer 2, and the two sets of adjustment mechanisms are all electrically connected to the controller.

[0040] Depending on the requirements, both the ultrasonic transducer and the controller can utilize existing known technologies. The vibration frequency range of the ultrasonic transducer is between 300kHz and 1MHz. The controller is a PLC controller. During installation, a mounting groove is made on each of the two side walls of the open channel, and the two brackets 3 are respectively installed in the mounting grooves on the two side walls of the open channel. During measurement, the controller controls the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 to move synchronously downwards from an initial height higher than the water level of the open channel, and simultaneously controls the downstream ultrasonic transducer 1 to emit ultrasonic signals and the counter-current ultrasonic transducer 2 to emit ultrasonic signals. Transducer 2 receives ultrasonic signals. Before the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 reach the water level of the open channel, the ultrasonic signal emitted by the downstream ultrasonic transducer 1 attenuates significantly in the air, causing the counter-current ultrasonic transducer 2 to be unable to receive the ultrasonic signal. Only when the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 reach the water level of the open channel, at which point the ultrasonic waves propagate in the liquid with less attenuation, can the counter-current ultrasonic transducer 2 receive the ultrasonic signal emitted by the downstream ultrasonic transducer 1. The controller then collects the ultrasonic signal emitted by the downstream ultrasonic transducer 1 at this point. The synchronous downward height of the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 is measured. Then, based on the initial height and the synchronous downward height of the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2, the water level in the open channel can be calculated. That is, the water level in the open channel can be measured using only the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2, eliminating the need for a separate water level gauge and reducing equipment costs. Furthermore, the controller can not only control and adjust the height of the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2, but also their angle. When measuring water flow velocity, the controller controls the downstream ultrasonic transducer 1 to move to the water level of the open channel according to the specific water level, and controls the upstream ultrasonic transducer 2 to move to the bottom of the open channel. Then, the controller controls the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 to rotate so that they face each other, so that they can transmit and receive ultrasonic signals. Then, the water flow velocity is calculated according to the time difference method, and finally the flow rate of the open channel can be obtained. That is, the height and angle of the ultrasonic transducer in this application can be automatically adjusted, so it is suitable for the measurement needs of different water levels and has good flexibility of use.

[0041] The above embodiments can be further optimized and / or improved according to actual needs:

[0042] Specifically, the adjustment mechanism includes a height adjustment mechanism and an angle adjustment mechanism. The height adjustment mechanism is mounted on the bracket 3, and the angle adjustment mechanism is mounted on the height adjustment mechanism. This allows the height and angle of the downstream ultrasonic transducer and the upstream ultrasonic transducer to be adjusted independently.

[0043] As attached Figure 2As shown, the height adjustment mechanism includes a lead screw 4, a lead screw 4 nut, guide rods 5, a slider 6, and a first drive motor 7. A rotatable lead screw 4 is vertically mounted on a bracket 3. A guide rod 5 is fixedly mounted on each side of the bracket 3 corresponding to the position of the lead screw 4. The slider 6 is slidably mounted on the two guide rods 5. The lead screw 4 nut is fixedly mounted on the slider 6 and fitted onto the lead screw 4. The top of the lead screw 4 is connected to the output shaft of the first drive motor 7. The first drive motor 7 is electrically connected to a controller. The angle adjustment mechanism is mounted on the slider 6. Depending on the requirements, the first drive motor 7 is a stepper motor. The slider 6 is moved up and down by the forward and reverse rotation of the first drive motor 7, thereby achieving the purpose of adjusting the height of the downstream and upstream ultrasonic transducers.

[0044] As attached Figure 3 As shown, the angle adjustment mechanism includes a mounting base 8, a rotating shaft 9, a first reduction gear 11, a second reduction gear 10, and a second drive motor 12. The mounting base 8 and the slider 6 are fixedly connected together. The rotating shaft 9 is rotatably mounted on the mounting base 8, and the second drive motor 12 is fixedly mounted on the mounting base 8. The first reduction gear 11 is mounted on the output shaft of the second drive motor 12, and the second reduction gear 10, which meshes with the first reduction gear 11, is mounted on the rotating shaft 9. The second drive motor 12 is electrically connected to the controller. The central axis of the rotating shaft 9 is perpendicular to the vertical plane where the downstream and upstream ultrasonic transducers are located. One set of adjustment mechanisms has a downstream ultrasonic transducer fixedly mounted on its rotating shaft 9, and the other set has a upstream ultrasonic transducer fixedly mounted on its rotating shaft 9. According to requirements, the downstream and upstream ultrasonic transducers are driven to rotate up and down by the forward and reverse rotation of the second drive motor 12, thereby achieving the purpose of adjusting the angle of the downstream and upstream ultrasonic transducers.

[0045] Example 2: The measurement method of this time-difference ultrasonic open channel water level and flow rate measuring device includes the following steps:

[0046] S1: Set initial height h0: During initial installation, the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 are located at the same height and face each other. This height is higher than the water level of the open channel. Record the height of the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 from the bottom of the open channel as the initial height h0.

[0047] S2: Calculate the water level height h1 of the open channel: The controller controls the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 to move downstream synchronously, and simultaneously controls the downstream ultrasonic transducer 1 to emit ultrasonic signals and the upstream ultrasonic transducer 2 to receive ultrasonic signals. When the upstream ultrasonic transducer 2 receives the ultrasonic signal emitted by the downstream ultrasonic transducer 1 for the first time, the controller collects the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2's downstream height h2. The controller calculates the water level height h1 of the open channel based on the initial height h0 and the downstream height h2.

[0048] S3: Calculate the angle between the propagation direction of the ultrasonic wave and the direction of water flow and the vertical direction: The controller controls the counter-current ultrasonic transducer 2 to descend to the bottom of the open channel; the controller calculates the angle between the propagation direction of the ultrasonic wave and the direction of water flow when the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 are facing each other, based on the width b of the open channel and the distance d between the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 along the direction of water flow, which should be θ1; the controller calculates the angle between the propagation direction of the ultrasonic wave and the vertical direction when the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 are facing each other, based on the width b of the open channel, the water level height h1, and the distance d between the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 along the direction of water flow, which should be θ2; the controller controls the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 to rotate so that the downstream ultrasonic transducer 1 and the counter-current ultrasonic transducer 2 are facing each other, based on the calculated θ1 and θ2.

[0049] S4: Calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions: The controller controls the downstream ultrasonic transducer 1 to emit ultrasonic signals and the upstream ultrasonic transducer 2 to receive ultrasonic signals, and collects the propagation time t1 of the ultrasonic waves when they propagate downstream; the controller controls the downstream ultrasonic transducer 1 to receive ultrasonic signals and the upstream ultrasonic transducer 2 to emit ultrasonic signals, and collects the propagation time t2 of the ultrasonic waves when they propagate upstream; calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions based on the collected t1 and t2.

[0050] S5: Calculate the flow velocity V of water in the open channel;

[0051] S6: Calculate the flow rate Q of the water in the open channel.

[0052] This measurement method is applicable to measuring the flow rate of clear water channels without siltation, as shown in the attached diagram. Figure 4-5As shown, given the initial height h0 and the downstream height h2, the water level h1 of the open channel can be calculated using the height difference h0-h2. When measuring the flow velocity V in the open channel, the downstream ultrasonic transducer 1 is moved to the water level height, and the upstream ultrasonic transducer 2 is moved to the bottom of the channel. Given the width b of the open channel and the distance d between the downstream and upstream ultrasonic transducers 1 and 2 along the flow direction, the angle θ1 between the ultrasonic wave propagation direction and the flow direction when the downstream and upstream ultrasonic transducers 1 and 2 are facing each other can be calculated. The distance L between transducer 1 and counter-current ultrasonic transducer 2 on the horizontal projection plane (the distance between transducer 1 and transducer 2 when they are at the same height) and the water level height h1 of the open channel obtained earlier can be used to calculate the angle θ2 between the direction of ultrasonic wave propagation and the vertical direction when transducer 1 and transducer 2 are facing each other. Specifically, the three parameters of initial height h0, width b of the open channel, and distance d between transducer 1 and transducer 2 along the water flow direction are entered into the controller in advance during the initial installation of the device.

[0053] In step S5, the controller calculates the flow velocity V of the water in the open channel based on the collected data using the following formula:

[0054]

[0055]

[0056]

[0057] Where C is the speed of sound in a stationary fluid and V is the flow velocity of water in an open channel. Combined with the width b and the water level h1 of the open channel, the controller can calculate the flow rate Q of the water in the open channel, thereby achieving the purpose of real-time measurement of the flow rate of the open channel.

[0058] Example 3: The measurement method of this time-difference ultrasonic open channel water level and flow rate measuring device includes the following steps:

[0059] S1: Set initial height h0: During initial installation, the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 are located at the same height and face each other. This height is higher than the water level of the open channel. Record the height of the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 from the bottom of the open channel as the initial height h0.

[0060] S2: Calculate the water level height h1 of the open channel: The controller controls the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 to move down synchronously for the first time, and simultaneously controls the downstream ultrasonic transducer 1 to emit ultrasonic signals and the upstream ultrasonic transducer 2 to receive ultrasonic signals. When the upstream ultrasonic transducer 2 receives the ultrasonic signal emitted by the downstream ultrasonic transducer 1 for the first time, the controller collects the height h3 of the first synchronous downward movement of the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2, and calculates the water level height h1 of the open channel based on the initial height h0 and the first synchronous downward movement height h3.

[0061] S3: Calculate the siltation height h2 of the open channel: Based on the width b of the open channel and the distance d between the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 along the water flow direction, the controller calculates the distance L between the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2. The controller then controls the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 to move synchronously downwards for the second time to a height of h1 / 2. Finally, the controller controls the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 to rotate downwards until their orientation makes an angle θ with the vertical direction. At position 3, and tanθ3=(L / 2) / (h1 / 2), the controller controls the downstream ultrasonic transducer 1 to emit ultrasonic signals and the upstream ultrasonic transducer 2 to receive ultrasonic signals. Then the controller controls the upstream ultrasonic transducer 2 to move upward. When the upstream ultrasonic transducer 2 receives the ultrasonic signal emitted by the downstream ultrasonic transducer 1, the controller collects the upward height h4 of the upstream ultrasonic transducer 2 and calculates the siltation height h2 of the open channel based on the upward height h4 of the upstream ultrasonic transducer 2.

[0062] S4: Calculate the water depth H of the open channel: Calculate the water depth H of the open channel based on the water level height h1 and the siltation height h2 of the open channel;

[0063] S5: Calculate the angle between the propagation direction of the ultrasonic wave and the direction of water flow and the vertical direction: The controller controls the downstream ultrasonic transducer 1 to move upward to a height of h1 and controls the upstream ultrasonic transducer 2 to move downward to a height of h2; the controller calculates the angle between the propagation direction of the ultrasonic wave and the direction of water flow when the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 are facing each other, based on the width b of the open channel and the distance d between the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 along the direction of water flow, which should be θ1; the controller calculates the angle between the propagation direction of the ultrasonic wave and the vertical direction when the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 are facing each other, based on the width b of the open channel, the water depth H of the open channel, and the distance d between the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 along the direction of water flow, which should be θ2; the controller controls the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 to rotate so that the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 are facing each other, based on the calculated θ1 and θ2.

[0064] S6: Calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions: The controller controls the downstream ultrasonic transducer 1 to emit ultrasonic signals and the upstream ultrasonic transducer 2 to receive ultrasonic signals, and collects the propagation time t1 of the ultrasonic waves when they propagate downstream; the controller controls the downstream ultrasonic transducer 1 to receive ultrasonic signals and the upstream ultrasonic transducer 2 to emit ultrasonic signals, and collects the propagation time t2 of the ultrasonic waves when they propagate upstream; calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions based on the collected t1 and t2.

[0065] S7: Calculate the flow velocity V of water in the open channel;

[0066] S8: Calculate the flow rate Q of water in the open channel.

[0067] This measurement method is applicable to measuring the flow rate of open channels with siltation at the bottom, as shown in the attached diagram. Figure 4 , 6 As shown in Figure 7, given the initial height h0 and the first synchronous descent height h3, the water level height h1 of the open channel is calculated using the height difference h0-h3. When the controller controls the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 to descend synchronously to a height of h1 / 2 for the second time, and then controls the downstream ultrasonic transducer 1 and the upstream ultrasonic transducer 2 to rotate downwards to a position where the angle between their orientation and the vertical direction is θ3, if there is no siltation at the bottom of the open channel, the ultrasonic wave emitted by the downstream ultrasonic transducer 1 can be received by the upstream ultrasonic transducer 2 after reflection from the bottom of the open channel. However, if there is siltation at the bottom of the open channel, the ultrasonic wave emitted by the downstream ultrasonic transducer 1 is reflected prematurely by the siltation. Therefore, the upstream ultrasonic transducer 2 at the height of h1 / 2 cannot receive the reflected ultrasonic wave. Only when the upstream ultrasonic transducer 2 rises to a certain height can it receive the reflected ultrasonic wave. (See attached figure.) Figure 5 It can be seen that the siltation height h2 of the open channel is equal to half of the upward height h4 of the counter-current ultrasonic transducer 2, that is, h2=h4 / 2. At this time, the water depth H of the open channel is h1-h2. According to the calculation formula in Example 2, the flow velocity V of the water in the open channel can be calculated. Then, combined with the width b of the open channel and the water depth H of the open channel, the controller can calculate the flow rate Q of the water in the open channel, thereby achieving the purpose of real-time measurement of the flow rate of the open channel.

[0068] The above technical features constitute the preferred embodiment of the present invention, which has strong adaptability and optimal implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the requirements of different situations.

Claims

1. A measurement method for a time-difference ultrasonic open channel water level and flow measurement device, based on the time-difference ultrasonic open channel water level and flow measurement device, which includes a downstream ultrasonic transducer, a counter-current ultrasonic transducer, two supports, and a controller. The downstream and counter-current ultrasonic transducers are respectively arranged on both sides of the open channel, with the downstream ultrasonic transducer arranged upstream and the counter-current ultrasonic transducer arranged downstream. The downstream and counter-current ultrasonic transducers are located in the same vertical plane to transmit and receive ultrasonic signals accordingly. The downstream and counter-current ultrasonic transducers are respectively mounted on the two supports through a set of adjustment mechanisms to adjust their height and angle in the vertical plane. The downstream and counter-current ultrasonic transducers and the two sets of adjustment mechanisms are all electrically connected to the controller. Includes the following steps: S1: Set initial height h0: During initial installation, the downstream ultrasonic transducer and the upstream ultrasonic transducer are located at the same height and face each other. This height is higher than the water level of the open channel. Record the height of the downstream ultrasonic transducer and the upstream ultrasonic transducer from the bottom of the open channel as the initial height h0. S2: Calculate the water level height h1 of the open channel: The controller controls the downstream ultrasonic transducer and the upstream ultrasonic transducer to move downstream synchronously, and simultaneously controls the downstream ultrasonic transducer to emit ultrasonic signals and the upstream ultrasonic transducer to receive ultrasonic signals. When the upstream ultrasonic transducer receives the ultrasonic signal emitted by the downstream ultrasonic transducer for the first time, the controller collects the downstream ultrasonic transducer and the upstream ultrasonic transducer's downstream ultrasonic transducer height h2. The controller calculates the water level height h1 of the open channel based on the initial height h0 and the downstream height h2. S3: Calculate the angle between the ultrasonic wave propagation direction and the water flow direction and the vertical direction: The controller controls the counter-current ultrasonic transducer to descend to the bottom of the open channel; the controller calculates the angle between the ultrasonic wave propagation direction and the water flow direction when the downstream and counter-current ultrasonic transducers are facing each other, which should be θ1, based on the width b of the open channel and the distance d between the downstream and counter-current ultrasonic transducers along the water flow direction; the controller calculates the angle between the ultrasonic wave propagation direction and the vertical direction when the downstream and counter-current ultrasonic transducers are facing each other, which should be θ2, based on the width b of the open channel, the water level h1 of the open channel and the distance d between the downstream and counter-current ultrasonic transducers along the water flow direction; the controller controls the downstream and counter-current ultrasonic transducers to rotate according to the calculated θ1 and θ2, so that the downstream and counter-current ultrasonic transducers face each other. S4: Calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions: The controller controls the downstream ultrasonic transducer to emit ultrasonic signals and the upstream ultrasonic transducer to receive ultrasonic signals, and collects the propagation time t1 of the ultrasonic waves when they propagate downstream; the controller controls the downstream ultrasonic transducer to receive ultrasonic signals and the upstream ultrasonic transducer to emit ultrasonic signals, and collects the propagation time t2 of the ultrasonic waves when they propagate upstream; calculate the ultrasonic propagation time difference Δt in the upstream and downstream directions based on the collected t1 and t2. S5: Calculate the flow velocity V of water in the open channel; S6: Calculate the flow rate Q of the water in the open channel.

2. The measurement method of the time-difference ultrasonic open channel water level and flow rate measuring device according to claim 1, characterized in that... The adjustment mechanism includes a height adjustment mechanism and an angle adjustment mechanism. The height adjustment mechanism is mounted on the bracket, and the angle adjustment mechanism is mounted on the height adjustment mechanism.

3. The measurement method of the time-difference ultrasonic open channel water level and flow rate measuring device according to claim 2, characterized in that... The height adjustment mechanism includes a lead screw, a lead screw nut, a guide rod, a slider, and a first drive motor. A rotatable lead screw is vertically mounted on a bracket. A guide rod is fixedly mounted on the bracket on each side of the lead screw. The slider is slidably mounted on the two guide rods. The lead screw nut is fixedly mounted on the slider and fitted onto the lead screw. The top of the lead screw is connected to the output shaft of the first drive motor. The first drive motor is electrically connected to the controller. The angle adjustment mechanism is mounted on the slider.

4. The measurement method of the time-difference ultrasonic open channel water level and flow rate measuring device according to claim 3, characterized in that... The angle adjustment mechanism includes a mounting base, a rotating shaft, a first reduction gear, a second reduction gear, and a second drive motor. The mounting base and the slider are fixedly connected together. The rotating shaft is rotatably mounted on the mounting base. The second drive motor is fixedly mounted on the mounting base. The first reduction gear is mounted on the output shaft of the second drive motor. The second reduction gear, which meshes with the first reduction gear, is mounted on the rotating shaft. The second drive motor and the controller are electrically connected. The central axis of the rotating shaft is perpendicular to the vertical plane where the downstream ultrasonic transducer and the upstream ultrasonic transducer are located. One set of adjustment mechanisms has a downstream ultrasonic transducer fixedly mounted on its rotating shaft, and the other set of adjustment mechanisms has a upstream ultrasonic transducer fixedly mounted on its rotating shaft.

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