Differential pressure type river water level and flow velocity sensor based on Bernoulli principle

Abstract

A flow velocity measuring tube, a main control module, a communication module and a lithium battery are all installed on a sinking frame, the sinking frame sinks into a riverbed and enables the flow velocity measuring tube to be in the water flow direction, and the flow velocity measuring tube is a reducer tube and comprises a first tube part and a second tube part; the pipe diameter of the first pipe part is larger than that of the second pipe part in the water flow direction, pressure sensors are arranged in the circumferential direction of the first pipe part and the circumferential direction of the second pipe part, the lithium battery provides electric energy for the pressure sensors, the main control module and the communication module, and the floating body floats on the water surface and is fixed to the sinking frame through a connecting rope. The communication module and the pressure sensor are connected with the main control module. Based on the Bernoulli principle, high-precision simultaneous measurement of the flow velocity and the water level of the river is realized by adopting a differential pressure measurement mode. The sensor is simple in design structure, clear in principle, free of interference and stable in data.

Description

Technical Field

[0001] The invention relates to a differential pressure river water level flow velocity sensor based on the Bernoulli principle. Background Art

[0002] The design of flow rate sensors is based on the basic principles of fluid mechanics, including the Bernoulli equation, continuity equation, energy equation, etc. These equations describe the behavior of fluids under different pipe diameters, pressures, and speeds, and are the theoretical basis for the design and application of flow rate sensors. With the development of fluid mechanics and measurement technology, different types of flow rate measurement methods have gradually matured, including: Mechanical: Based on the mechanical structure (such as turbine, rotor, etc.) to sense the fluid flow rate, the flow rate is converted by the frequency or angular velocity of rotation. This technology is relatively traditional and has low sensitivity at low flow rates.

[0003] Electromagnetic: Based on Faraday's law of electromagnetic induction, the flow velocity is measured by using the electromotive force generated when the flowing conductive liquid cuts the magnetic lines of force in the magnetic field. This technology is suitable for measuring the flow velocity of conductive liquids and is widely used in industrial process control. It is susceptible to electromagnetic interference.

[0004] Ultrasonic type: Utilizes the principle that the propagation speed and phase of ultrasonic signals change with the flow rate of the fluid, and measures the flow rate through the Doppler effect or time difference method. This sensor can be applied to non-conductive liquids or gases, has high requirements on the density, temperature and particulate matter of the fluid, and is relatively expensive.

[0005] Thermal type: Use thermistors or hot wires to sense the temperature change when the fluid flows through the heating element, and detect the flow rate through heat conduction or convection. This sensor has high accuracy and is suitable for measuring low-speed gas flow rates, such as wind speed measurement in environmental monitoring. It is unstable in high-temperature or high-speed fluids and is not suitable for high-speed flow measurement.

[0006] Laser Doppler (LDV) and Particle Image Velocimetry (PIV): High-precision flow velocity measurement for fluid dynamics research, mainly used in scientific research, especially in the study of fine structures in flow fields. High cost and difficult to measure continuously. Summary of the invention

[0007] The present invention aims to solve the problems existing in the above-mentioned prior art and provides a differential pressure river water level flow velocity sensor based on the Bernoulli principle.

[0008] The technical solutions adopted in the present invention are: A differential pressure river water level flow rate sensor based on the Bernoulli principle comprises a bottom frame, a flow rate measuring tube, a floating body, a pressure sensor, a main control module, a communication module and a lithium battery. The flow rate measuring tube, the main control module, the communication module and the lithium battery are all installed on the bottom frame. The bottom frame sinks into the riverbed and makes the flow rate measuring tube follow the direction of water flow. The flow rate measuring tube is a variable diameter tube, comprising a first tube part and a second tube part. The tube diameter of the first tube part along the direction of water flow is larger than the tube diameter of the second tube part. Pressure sensors are arranged in the circumference of the first tube part and the second tube part. The lithium battery provides electric energy for the pressure sensor, the main control module and the communication module. The floating body floats on the water surface and is fixed to the bottom frame by a connecting rope. The communication module and the pressure sensor are both connected to the main control module.

[0009] Furthermore, two pressure sensors are symmetrically arranged on the outer wall of the first tube part and the outer wall of the second tube part, and are marked as S1 and S2 respectively. The pressure sensor on the first tube part and the pressure sensor on the second tube part are both located at the side center line of the corresponding tube part, and the pressure sensor on the first tube part and the pressure sensor on the second tube part are on the same horizontal line.

[0010] Furthermore, the diameter of the first pipe is 2-4 times the diameter of the second pipe. The main control module collects the pressures P1 and P2 in the flow velocity measurement pipes S1 and S2 in real time and calculates the river flow velocity V. The calculation formula is: V=sqrt(2*(P1-P2) / ρ / ((d1 / d2)^4-1)); The calculation formula for calculating the river water level H is: H=h0+(P1+0.5*ρ* V^2) / ( ρ*g); Wherein, V is the flow velocity of the river; P1 is the pressure measured by S1, P2 is the pressure measured by S2, ρ is the density of water, d1 is the diameter of the first pipe, and d2 is the diameter of the second pipe; h0 is the height of the pressure sensor from the riverbed reference water level.

[0011] Furthermore, the sink frame is also provided with a power generation mechanism to charge the lithium battery.

[0012] Furthermore, the power generation mechanism is a 5V DC micro-turbine generator for charging a 5V lithium battery.

[0013] Furthermore, the floating body includes a rubber body and a mounting frame, and four rubber bodies are grouped in pairs and are respectively fixed on both sides of the mounting frame.

[0014] Furthermore, the bottom frame includes a support frame and a fixing ring, the two support frames are arranged in parallel and at intervals, a plurality of fixing rings are fixed between the two support frames, the first tube portion and the second tube portion of the flow velocity measuring tube are inserted into the corresponding fixing rings, and the flow velocity measuring tube and the fixing ring are fixed by bolts.

[0015] Furthermore, a counterweight is fixed on the support frame.

[0016] Furthermore, a positioning antenna is provided on the floating body, and the positioning antenna is connected to the main control module.

[0017] The present invention has the following beneficial effects: The present invention is based on the Bernoulli principle and uses differential pressure measurement to achieve high-precision simultaneous measurement of river flow velocity and water level. The sensor has a simple design structure, clear principle, no interference, and stable data. It has uninterrupted charging and wireless communication, and does not require special deployment of power supply lines and communication networks. It is easy to deploy and maintenance-free, and can achieve low-cost real-time flow velocity and water level monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a structural diagram of the present invention.

[0019] Figure 2 This is a measurement principle diagram of the present invention.

[0020] Figure 3 This is a structural diagram of a floating body.

[0021] Figure 4 This is the installation structure diagram of the flow measurement tube on the bottom frame. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings.

[0023] like Figure 1 As shown, the differential pressure type river water level flow velocity sensor based on the Bernoulli principle of the present invention comprises a bottom frame 1, a flow velocity measuring tube 2, a floating body 3, a pressure sensor, a main control module, a communication module and a lithium battery.

[0024] The flow velocity measuring tube 2 is fixed on the bottom frame 1, the bottom frame 1 sinks into the riverbed and makes the flow velocity measuring tube 2 follow the direction of water flow. The flow velocity measuring tube 2 is a reducer tube, including a first tube portion 21 and a second tube portion 22. Along the direction of water flow, the diameter of the first tube portion 21 is larger than the diameter of the second tube portion 22, and the diameter of the first tube portion 21 is 2-4 times the diameter of the second tube portion 22.

[0025] Two pressure sensors are symmetrically disposed on the outer wall of the first tube portion 21 and the outer wall of the second tube portion 22 , and are marked as S1 and S2 respectively.

[0026] The floating body 3 floats on the water surface and is fixed to the bottom frame 1 by a connecting rope. The main control module, communication module and lithium battery are fixed on the bottom frame 1. The lithium battery provides power for the pressure sensor, main control module and communication module. The communication module and pressure sensor are both connected to the main control module.

[0027] like Figure 2 The present invention is based on the Bernoulli principle and uses differential pressure measurement to achieve high-precision simultaneous measurement of river flow velocity and water level. The measurement principle is as follows: The main control module collects the pressures P1 and P2 in the flow velocity measurement tubes S1 and S2 in real time and calculates the river flow velocity V. The calculation formula is: V=sqrt(2*(P1-P2) / ρ / ((d1 / d2)^4-1)); The calculation formula for calculating the river water level H is: H=h0+(P1+0.5*ρ* V^2) / ( ρ*g); Wherein, V is the river flow velocity; P1 is the pressure measured by S1, P2 is the pressure measured by S2, ρ is the density of water, d1 is the diameter of the first pipe, d2 is the diameter of the second pipe; h0 is the height of the pressure sensor from the reference water level of the riverbed.

[0028] A power generation mechanism 4 is also provided on the bottom frame 1 to charge the lithium battery. The power generation mechanism 4 adopts a 5V DC micro-turbine generator to charge the 5V lithium battery.

[0029] like Figure 3 The floating body 3 includes a rubber body 31 and a mounting frame 32. Four rubber bodies 31 are fixed on both sides of the mounting frame 32 in pairs. A positioning antenna is also provided on the floating body 3. The positioning antenna is connected to the main control module. The measurement side data can be transmitted to the local client through the communication module. The longitude and latitude positioning of the collection node is realized through the positioning antenna (i.e., GPS) for easy management.

[0030] like Figure 4 The bottom frame 1 includes a support frame 11 and a fixing ring 12. The two support frames 11 are arranged in parallel and at intervals. A plurality of fixing rings 12 are fixed between the two support frames 11. The first pipe portion 21 and the second pipe portion 22 of the flow velocity measuring tube 2 are inserted into the corresponding fixing rings 12, and the flow velocity measuring tube 2 and the fixing rings 12 are fixed by bolts. In order to ensure the positioning effect, a step surface is provided on the first pipe portion 21, and the step surface contacts the corresponding fixing ring 12. The step surface between the first pipe portion 21 and the second pipe portion 22 also contacts the corresponding fixing ring 12.

[0031] A counterweight is also fixed on the support frame 11 for better sinking to the bottom.

[0032] The pressure sensor in the present invention adopts an oil-filled isolation pressure sensor, and the communication module is a GSM antenna interface, which can realize the functions of SMS sending and receiving and TCP communication. It is responsible for uploading the river flow rate and river water level calculated by the main control module to the cloud monitoring system. The positioning antenna provides an active GPS interface and a Beidou interface to realize the longitude and latitude positioning of the collection node. A cloud monitoring system software is also provided. The cloud monitoring system software is the server end of the C / S program, which is responsible for monitoring and receiving the connection and data transmission of each monitoring and collection node, and the received information includes the node water level, flow rate and positioning information.

[0033] The main control module has a periodic wake-up function and can wake up for 10 seconds every few hours. The sleep time and working time parameters can be set locally or controlled by commands issued by the cloud software. After waking up, the main control module collects water level and flow rate information, establishes a TCP connection with the cloud, sends water seepage information and terminal device number, and disconnects the TCP connection after waiting for confirmation from the cloud. The main control module regularly collects longitude and latitude information and battery power information and sends it to the cloud via TCP. The collection period can be set; you can also send commands in the cloud monitoring software to instantly collect node longitude and latitude information or battery power information.

[0034] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A differential pressure river water level and flow velocity sensor based on the Bernoulli principle, characterized in that: The invention comprises a bottom sinking frame (1), a flow rate measuring tube (2), a floating body (3), a pressure sensor, a main control module, a communication module and a lithium battery. The flow rate measuring tube (2), the main control module, the communication module and the lithium battery are all installed on the bottom sinking frame (1). The bottom sinking frame (1) sinks into the riverbed and allows the flow rate measuring tube (2) to flow along the direction of the water flow. The flow rate measuring tube (2) is a variable diameter tube, comprising a first tube portion (21) and a second tube portion (22). The diameter of the first tube portion (21) is larger than the diameter of the second tube portion (22) along the direction of the water flow. Pressure sensors are provided in the circumference of the first tube portion (21) and the second tube portion (22). The lithium battery provides electric energy for the pressure sensor, the main control module and the communication module. The floating body (3) floats on the water surface and is fixed to the bottom sinking frame (1) by a connecting rope. The communication module and the pressure sensor are both connected to the main control module.

2. The differential pressure river water level and flow velocity sensor based on the Bernoulli principle as claimed in claim 1, characterized in that: Two pressure sensors are symmetrically arranged on the outer wall of the first tube part (21) and the outer wall of the second tube part (22), and are marked as S1 and S2 respectively.

3. The differential pressure river water level and flow velocity sensor based on the Bernoulli principle as claimed in claim 2, characterized in that: The diameter of the first pipe part (21) is 2-4 times the diameter of the second pipe part (22). The main control module collects the pressures P1 and P2 in the flow velocity measuring pipes S1 and S2 in real time and calculates the river flow velocity V. The calculation formula is: V=sqrt(2*(P1-P2) / ρ / ((d1 / d2)^4-1)); The calculation formula for calculating the river water level H is: H=h0+(P1+0.5*ρ* V^2) / ( ρ*g); Wherein, V is the flow velocity of the river; P1 is the pressure measured by S1, P2 is the pressure measured by S2, ρ is the density of water, d1 is the diameter of the first pipe, and d2 is the diameter of the second pipe; h0 is the height of the pressure sensor from the riverbed reference water level.

4. The differential pressure river water level and flow velocity sensor based on the Bernoulli principle as claimed in claim 1, characterized in that: The sink frame (1) is also provided with a power generation mechanism (4) for charging the lithium battery.

5. The differential pressure river water level and flow velocity sensor based on the Bernoulli principle as claimed in claim 4, characterized in that: The power generation mechanism (4) is a 5V DC micro-turbine generator, which is used to charge a 5V lithium battery.

6. The differential pressure river water level and flow velocity sensor based on the Bernoulli principle as claimed in claim 1, characterized in that: The floating body (3) comprises a rubber body (31) and a mounting frame (32), and four rubber bodies (31) are grouped in pairs and are respectively fixed on both sides of the mounting frame (32).

7. The differential pressure river water level and flow velocity sensor based on the Bernoulli principle as claimed in claim 1, characterized in that: The bottom frame (1) comprises a support frame (11) and a fixing ring (12); the two support frames (11) are arranged in parallel and at intervals; a plurality of fixing rings (12) are fixed between the two support frames (11); a first tube portion (21) and a second tube portion (22) of a flow velocity measuring tube (2) are inserted into corresponding fixing rings (12); and the flow velocity measuring tube (2) and the fixing ring (12) are fixed by bolts.

8. The differential pressure river water level and flow velocity sensor based on the Bernoulli principle as claimed in claim 7, characterized in that: A counterweight is fixed on the support frame (11).

9. The differential pressure river water level and flow velocity sensor based on the Bernoulli principle as claimed in claim 1, characterized in that: The floating body (3) is provided with a positioning antenna, which is connected to the main control module.

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