Passive water flow monitoring system

Abstract

The invention provides a passive water flow monitoring system, which is installed at a liquid outlet, utilizes water flow to push a power generation module to generate power, stores energy and stabilizes voltage through a source processing module, and supplies power to a main controller and a wireless transmitting module, thereby realizing flow state detection and wireless transmission without an external power supply and wiring. The detection end is composed of a power generation module, a power supply processing module, a main controller, a detection module and a wireless transmitting module. The receiving end comprises a wireless receiving module, a main control module and a user interface; by detecting a rotating speed signal driven by water flow and wirelessly transmitting the rotating speed signal, real-time monitoring on whether liquid flows or not can be realized. The system has the advantages of no need of power supply and wiring, simplicity and convenience in installation, high sensitivity, low energy consumption, real-time remote monitoring and the like, can effectively prevent no-load operation of equipment such as a water pump and the like, reduces the maintenance cost, and is suitable for popularization and application in the fields of industrial automation, water treatment, consumer electronics and the like.

Description

Technical Field

[0001] This invention relates to the field of fluid monitoring and sensing technology, specifically to a passive system for monitoring the presence or absence of water flow. Background Technology

[0002] In the field of sensors or monitoring systems, "passive" generally means that the device itself does not require an external power supply. The meaning of "whether there is water flow" is not to measure the precise flow rate (how many liters / minute), but to monitor whether there is water flow or not.

[0003] Liquid flow monitoring is widely used in industrial automation, water treatment, chemical industry, agriculture and water-related pumps and other consumer equipment. Traditional methods mostly rely on mechanical or electronic flow meters, which usually require external power supply and transmit data via wired means. Installation is limited by cable length and wiring conditions, and maintenance is a lot of work, which is especially inconvenient in long-distance or distributed scenarios.

[0004] Shortcomings of existing technology: 1. High dependence on external energy and wiring: Existing liquid flow sensors generally require an external power supply, which leads to complex wiring, increased energy consumption, and inflexible deployment, making them unsuitable for distributed and long-distance installation.

[0005] 2. High maintenance costs: Traditional solutions often require manual inspection and real-time monitoring, which is time-consuming and labor-intensive, and cannot meet the needs of continuous monitoring.

[0006] 3. Stability of power supply and detection under low flow rate and intermittent flow conditions: How to continuously obtain sufficient energy and maintain stable power supply under low flow rate conditions, while accurately identifying states such as "with / without flow", remains a key challenge.

[0007] Therefore, existing technologies have shortcomings and need further improvement. Summary of the Invention

[0008] To address the problems existing in the prior art, this invention provides a passive water flow monitoring system.

[0009] To achieve the above objectives, the specific solution of the present invention is as follows: This invention provides a passive water flow monitoring system, comprising: a detection end installed at the liquid outlet and a remotely located receiving end. The detection end includes: A power generation module includes an impeller assembly and an electromagnetic power generation device. The impeller assembly is driven to rotate by the flow of liquid and generates electrical energy through the electromagnetic power generation device. The power processing module is electrically connected to the power generation module. It rectifies, stores, and stabilizes the electrical energy output by the power generation module before providing a stable power supply to the subsequent circuits. The main control module is connected to the power processing module for power supply, receives signals from the detection module, and controls the operation of the wireless transmission module. The detection module detects the rotation parameters of the impeller assembly to obtain liquid flow information and transmits the liquid flow information to the main control module. A wireless transmission module is connected to the main control module and transmits liquid flow information to the receiving end via Bluetooth, WiFi, or LoRa wireless communication. The receiving end includes: a wireless receiving module, a receiving end main control module, and a user interface; wherein, the wireless receiving module is used to receive liquid flow information sent by the wireless transmitting module, the receiving end main control module is used to process the received liquid flow information, and the user interface is used to output the liquid flow information to the user.

[0010] Furthermore, the power generation module includes an electromagnetic generator integrated with the impeller assembly. A permanent magnet is mounted on the shaft of the impeller assembly, and an electromagnetic coil is disposed outside it. When the liquid flow drives the impeller assembly to rotate, the permanent magnet and the electromagnetic coil move relative to each other to generate current.

[0011] Furthermore, the power processing module includes a rectifier circuit, an energy storage element, and a voltage regulator circuit; The rectifier circuit converts the AC power output from the power generation module into DC power, the energy storage element stores the electrical energy, and the voltage regulator circuit outputs stable DC power for use by the main control module and the wireless transmission module.

[0012] Furthermore, the detection module includes a rotational speed sensor; the rotational speed sensor detects the rotational speed of the impeller assembly to obtain liquid flow information; the rotational speed sensor is selected from a Hall sensor or a photoelectric sensor.

[0013] Furthermore, the user interface of the receiving end includes at least one of a display screen, an audible and visual alarm, or a wireless communication interface; when the main control module of the receiving end determines that the liquid flow information is abnormal (such as the flow rate exceeding a preset threshold or no flow for a long time), the audible and visual alarm can trigger an alarm, or push the abnormal information to a remote terminal through the wireless communication interface.

[0014] Furthermore, the detection end also includes a flexible piezoelectric power generation module, which includes a flexible piezoelectric material fixed to the inner wall of the liquid flow channel and extending into the flow channel. When the liquid flows, the flexible piezoelectric material vibrates and generates electrical energy. The output of the flexible piezoelectric power generation module is rectified and connected to the power processing module to provide power to the detection end.

[0015] Furthermore, the detection end also includes a triboelectric nano-power generation module, which includes a stator friction layer and a rotor friction layer arranged opposite to each other, and a magnetic coupling transmission component connected to the rotor friction layer. When the liquid flow drives the magnetic coupling transmission component to rotate, it drives the rotor to move relative to the stator and generate electrical energy. The output of the triboelectric nano-power generation module is rectified and then connected to the power processing module.

[0016] Furthermore, the detection end also includes an auxiliary energy acquisition module, which includes at least one solar photovoltaic panel and at least one thermoelectric power generation element; the solar photovoltaic panel is disposed on the outer surface of the detection end to collect light energy; the thermoelectric power generation element converts the ambient temperature difference into electrical energy; the output of the auxiliary energy acquisition module is connected to the power processing module; the main control module is provided with a multi-channel power management circuit, which automatically switches between different energy inputs according to the energy input situation to maintain a stable power supply.

[0017] Furthermore, the power generation module is a multi-stage composite power generation structure, including multi-stage impellers arranged on the same rotating shaft, and multiple electromagnetic power generation coils corresponding to each stage of the impeller, or multi-phase electromagnetic winding coils arranged on the same impeller assembly, thereby broadening the applicable flow rate range of the device and improving the power generation efficiency under low flow rate conditions.

[0018] Furthermore, the main control module and wireless transmission module of the detection end adopt a low-power sleep / wake-up design. When there is no liquid flow, it enters a sleep state to reduce power consumption. When liquid flow is detected or the preset sleep time, such as 5 minutes or 10 minutes, it automatically wakes up to collect and transmit data.

[0019] The technical solution of this invention has the following beneficial effects: 1. No external power supply or wiring required: The sensing device is self-powered by utilizing the energy of liquid flow, avoiding complex wiring and line loss problems, and improving installation flexibility and applicability.

[0020] 2. Energy-saving and environmentally friendly, with a high degree of automation: The equipment generates its own electricity and operates without manual intervention or battery replacement, which greatly reduces maintenance costs; combined with low power consumption strategies and multiple energy harvesting methods, it can effectively extend the service life of the equipment.

[0021] 3. Real-time wireless monitoring: The device integrates wireless communication function, which can transmit information such as whether the liquid is flowing and its flow rate to the remote monitoring system or user terminal in real time, so as to realize remote monitoring and linkage control without geographical restrictions. Attached Figure Description

[0022] Figure 1 This is a block diagram of the present invention; Figure 2 This is the circuit diagram of the present invention; Figure 3 This is a schematic diagram of the structure of the present invention.

[0023] Attached image captions: 1. Power generation module; 2. Power processing module; 3. Main control module; 4. Detection module; 5. Wireless transmission module; 6. Wireless receiving module; 7. Receiver main control module; 8. User interface. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0025] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] In the description of this embodiment, the terms "upper," "lower," "front," "rear," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used only for descriptive distinction and have no special meaning.

[0028] Combination Figures 1-3As shown, the present invention provides a passive water flow monitoring system, comprising: a detection end installed at the liquid outlet and a remotely located receiving end. The detection end includes: A power generation module includes an impeller assembly and an electromagnetic power generation device. The impeller assembly is driven to rotate by the flow of liquid and generates electrical energy through the electromagnetic power generation device. The power processing module is electrically connected to the power generation module. It rectifies, stores, and stabilizes the electrical energy output by the power generation module before providing a stable power supply to the subsequent circuits. The main control module is connected to the power processing module for power supply, receives signals from the detection module, and controls the operation of the wireless transmission module. The detection module detects the rotation parameters of the impeller assembly to obtain liquid flow information and transmits the liquid flow information to the main control module. A wireless transmission module is connected to the main control module and transmits liquid flow information to the receiving end via Bluetooth, WiFi, or LoRa wireless communication. The receiving end includes: a wireless receiving module, a receiving end main control module, and a user interface; wherein, the wireless receiving module is used to receive liquid flow information sent by the wireless transmitting module, the receiving end main control module is used to process the received liquid flow information, and the user interface is used to output the liquid flow information to the user.

[0029] The power generation module includes an electromagnetic generator integrated with the impeller assembly. A permanent magnet is mounted on the shaft of the impeller assembly, and an electromagnetic coil is disposed outside it. When the liquid flows and drives the impeller assembly to rotate, the permanent magnet and the electromagnetic coil move relative to each other to generate current.

[0030] The power processing module includes a rectifier circuit, an energy storage element, and a voltage regulator circuit; The rectifier circuit converts the AC power output from the power generation module into DC power, the energy storage element stores the electrical energy, and the voltage regulator circuit outputs stable DC power for use by the main control module and the wireless transmission module.

[0031] The detection module includes a rotational speed sensor; the rotational speed sensor detects the rotational speed of the impeller assembly to obtain liquid flow information; the rotational speed sensor is selected from Hall sensors or photoelectric sensors.

[0032] The user interface of the receiving end includes at least one of a display screen, an audible and visual alarm, or a wireless communication interface; when the main control module of the receiving end determines that the liquid flow information is abnormal, such as the flow rate exceeding a preset threshold or no flow for a long time, the audible and visual alarm can trigger an alarm, or push the abnormal information to a remote terminal through the wireless communication interface.

[0033] The detection end also includes a flexible piezoelectric power generation module, which includes a flexible piezoelectric material fixed to the inner wall of the liquid flow channel and extending into the flow channel. When the liquid flows, the flexible piezoelectric material vibrates and generates electrical energy. The output of the flexible piezoelectric power generation module is rectified and connected to the power processing module to provide power to the detection end.

[0034] The detection end also includes a triboelectric nano-power generation module, which includes a stator friction layer and a rotor friction layer arranged opposite to each other, and a magnetic coupling transmission component connected to the rotor friction layer. When the liquid flow drives the magnetic coupling transmission component to rotate, it drives the rotor to move relative to the stator and generate electrical energy. The output of the triboelectric nano-power generation module is rectified and then connected to the power processing module.

[0035] The detection end also includes an auxiliary energy acquisition module, which includes at least one solar photovoltaic panel and at least one thermoelectric power generation element. The solar photovoltaic panel is disposed on the outer surface of the detection end to collect light energy. The thermoelectric power generation element converts the ambient temperature difference into electrical energy. The output of the auxiliary energy acquisition module is connected to the power processing module. The main control module is provided with a multi-channel power management circuit, which automatically switches between different energy inputs according to the energy input situation to maintain a stable power supply.

[0036] The power generation module is a multi-stage composite power generation structure, including multi-stage impellers set on the same rotating shaft and multiple electromagnetic power generation coils corresponding to each stage of the impeller, or multi-phase electromagnetic winding coils set on the same impeller assembly, thereby broadening the applicable flow rate range of the device and improving the power generation efficiency under low flow rate conditions.

[0037] The main control module and wireless transmission module of the detection terminal adopt a low-power sleep / wake-up design. When there is no liquid flow, it enters a sleep state to reduce power consumption. When liquid flow is detected or the preset sleep time, such as 5 minutes or 10 minutes, it automatically wakes up to collect and transmit data.

[0038] Figure 2 This is a circuit diagram, which contains several key parts: The detection end consists of a power generation module composed of a coil and an electromagnet, a filter circuit composed of a rectifier bridge D1 and capacitors C1, C2 and C6, a voltage regulation circuit composed of IC1, resistors R1 and R2 and capacitors C5, C3, C4 and C7 to form a power processing module, a control module composed of a microcontroller U1, a Hall sensor detection module, and a wireless transmission module. Receiver: The control module consists of a wireless receiver module and a microcontroller U2.

[0039] 1. Bridge rectifier circuit section Components: Bridge rectifier (D1), capacitors (C1, C2, C6).

[0040] Application: This part of the circuit converts alternating current (AC) to direct current (DC). The bridge rectifier (D1) rectifies the AC current through four diodes and then smooths the DC power supply through capacitors (C1, C2, C6) to reduce ripple.

[0041] 2.3.3V voltage regulation circuit Components: Voltage regulator (U1), capacitors (C1, C2), resistor (R1), LED indicator (LED1).

[0042] Application: This part of the circuit converts the input voltage (typically 5V or higher) to a stable 3.3V output. A voltage regulator (SGM2103) is used to control the output voltage stability. Resistors and capacitors are used for filtering and stabilizing the power supply, and an LED (LED1) is used to indicate the power supply status.

[0043] 3. Wireless receiver module section Component: Wireless receiver module (wireless receiver module part).

[0044] Application: This part of the circuit is responsible for receiving wireless signals. The circuit acquires external signals through a wireless receiver module and may convert the signals into digital data for subsequent processing. This module connects to the input of the microcontroller for data reception.

[0045] 4. Microcontroller section Components: STC15W201S microcontroller (U1), STC15W401AS microcontroller (U2), other pins (P1, P2, P3).

[0046] Application: These two microcontrollers are responsible for the control and management of the entire circuit. The STC15W201S (U1) mainly handles signal reception and control, while the STC15W401AS (U2) handles higher-level control tasks. Pins connect to various peripherals, such as ADC, SPI, and GPIO, for inputting and outputting external signals.

[0047] 5. Other parts LED indicator lights: LED1 and LED2 respectively display different working statuses, such as the working status of the power supply or the system running status.

[0048] Interconnection Power Supply Section: A bridge rectifier circuit provides the input power, which is converted to 3.3V by a voltage regulator to power the microcontroller and wireless receiver module. The output of the voltage regulator is also connected to an LED to indicate the power supply status.

[0049] Wireless signal reception: The wireless receiving module transmits the received signal to the microcontroller (U1, U2), and the microcontroller processes the data to determine the next action or response.

[0050] Microcontroller control: The microcontroller communicates with the wireless receiver module, LEDs, and possibly other peripherals (such as sensors, displays, etc.) through its pins to manage data flow and system status.

[0051] In summary, the main functions of this circuit are to receive, process, and manage the power of wireless signals, while providing status feedback through LED indicators.

[0052] The principle of this invention is as follows: I. General Principles The device is installed at the water outlet. The water flow drives the internal rotor (with permanent magnets) to rotate, inducing alternating voltage in the winding coils and completing energy harvesting. After rectification, energy storage, and voltage stabilization, it provides a stable power supply for the main control and wireless transmission. The main control collects speed pulses (representing the flow state / velocity), packages them, and wirelessly transmits them to the receiving end. The receiving end decodes and outputs the data to the user interface, enabling remote monitoring of the presence / absence of water flow and changes in flow.

[0053] II. Energy and Signal Chain at the Detection End Hydropower → Electrical power (power generation module) The water flow creates a pressure difference that causes the rotor to rotate; multiple pairs of staggered magnetic poles on the rotor form an electromagnetic induction with the stator coils, outputting an AC voltage (power estimated at about 1W, requiring only a drive control / detection / wireless module).

[0054] Rectification / Energy Storage / Voltage Regulation (Power Processing Module) The AC power is smoothed by a rectifier bridge and a filter capacitor, and some of the power is stored in a large-capacity capacitor to maintain power supply during intermittent / low flow rates; then a voltage regulator IC outputs a **stable DC voltage (3.3V in example)** for use by subsequent stages.

[0055] Flow detection and data generation (detection module + main control) When the rotor magnetic poles pass over the Hall sensor, a voltage jump / pulse is generated. The main controller (MCU) collects the pulse edge and counts to obtain flow information related to the rotational speed (e.g., when there are 4 pairs of magnetic poles, 4 voltage changes are generated per revolution). The main controller packages data such as "there is / there is no flow, flow change / strength" according to the communication protocol.

[0056] Wireless transmission (wireless transmitter module) After the main controller is powered on, it wakes up the wireless module (which can be 433MHz / Bluetooth / Wi-Fi, etc., example: 433MHz, about 5m transmission distance), establishes communication and sends periodically when water flow is detected; when the flow approaches zero, it sends a final pause signal and then disconnects the communication to save energy and define the state boundary.

[0057] Correspondence: The functional module block diagram and circuit schematic are shown on pages 3 and 4; the rectification, energy storage, capacitor and voltage regulation links, as well as the MCU / wireless connection, have a clear correspondence in the schematic.

[0058] III. Receiving End and Judgment The receiver consists of a wireless receiver module and an MCU. It decodes the data sent by the detection end and drives the user interface (such as indicator / alarm / host computer) to determine whether there is water flow at the outlet and the trend of flow rate change, so as to realize remote monitoring and linkage control.

[0059] IV. Low power consumption and intermittent operation strategy (optional implementation) In energy-constrained / intermittent flow conditions, the system operates through: The energy storage capacitor maintains short-term operation and completes the transmission of critical messages; The MCU / wireless sleep-wake mechanism only wakes up when movement is detected or a timer is reached. DC-DC voltage regulation ensures stable power supply, enabling detection and reporting to be completed even at low flow rates.

[0060] V. Typical Work Process (Scenario-based Description) Water plant outlet → water flow drives impeller → electromagnetic induction power generation → rectification / energy storage / voltage stabilization → MCU reads Hall pulse and determines "current" → wirelessly transmits to receiver → host computer / controller displays or alarms; if no message is received for a long time or a "pause signal" is received, it is determined that there is no water flow / abnormality, which is used to prevent the water pump from being unloaded.

[0061] Example 1: Self-Powered Liquid Flow Sensing Device Based on Turbine-Electromagnetic Generation This embodiment provides a liquid flow sensing device that utilizes a micro turbine to generate electricity. The detection end of the device includes: an impeller assembly, an electromagnetic power generation module coaxially connected to the impeller, a rectifier and voltage regulator processing module, a microcontroller main control module, a flow detection module, and a wireless transmission module.

[0062] Structural Composition: The impeller assembly is installed at the outlet of the pipe containing the liquid being tested. It can be fixed to the inner wall of the pipe by threads or clips, ensuring that the impeller can directly contact the flowing liquid. The impeller is made of corrosion-resistant and wear-resistant materials to withstand prolonged immersion and impact. A permanent magnet is integrated on the impeller shaft, forming a miniature electromagnetic generator (power generation module) together with a coil arranged around the shaft. When the liquid flows through the outlet, it drives the impeller to rotate, causing the permanent magnet to rotate and cut the magnetic field of the coil, generating induced alternating current. The alternating current output from the power generation module is converted to direct current by a rectifier bridge D1, and after being filtered and smoothed by a capacitor, it is regulated by the power processing module. The power processing module may include energy storage elements (such as energy storage capacitors or rechargeable batteries) to store electrical energy and ensure a stable and continuous output voltage. The regulated direct current supplies power to the main control module and also provides operating power to the detection module and the wireless transmission module.

[0063] Working Principle: This device generates its own power and begins monitoring whenever liquid flows over the impeller. The impeller rotation speed is directly proportional to the liquid flow rate, thus serving as the basis for flow measurement. The detection module uses a Hall effect sensor placed close to the impeller magnet to sense the magnetic field pulses generated with each rotation, thereby acquiring the impeller speed signal (a photoelectric sensor can also be used to detect the pulses passing through the impeller blades). The main control module consists of a low-power MCU (such as an STM32 series or Arduino), which is normally in sleep mode to conserve energy. It is awakened when a valid flow signal is detected or a preset acquisition interval is reached. The MCU reads and processes the sensor signals, calculating the instantaneous liquid velocity, cumulative flow, or determining the presence or absence of flow. It also detects the start, stop, and sudden changes in flow velocity using pre-set algorithms. For example, the MCU can calculate the instantaneous flow rate by counting pulses within a set time window and estimate the cumulative liquid flow rate by accumulating the total number of pulses. When no new pulses are detected within a predetermined time period, the liquid flow is considered to have stopped; the re-detection of pulses indicates that the flow has resumed; and a drastic change in the pulse frequency per unit time is identified as a sudden change in flow velocity. Using this algorithm, the system can track changes in the liquid flow state in real time, improving the accuracy and timeliness of detection. Subsequently, the main control module controls the wireless transmission module to package and appropriately compress the monitoring data before transmitting it through the antenna, achieving long-distance wireless transmission of liquid flow information. The wireless module can use communication methods such as Bluetooth Low Energy, LoRa, or NB-IoT, depending on the application requirements. To reduce energy consumption, the system only wakes up the wireless module when new data needs to be transmitted; otherwise, it shuts down the wireless circuitry. The receiving end can be located remotely, such as a gateway device in a central monitoring room or a user's mobile terminal. Upon receiving the wireless signal, it can determine the flow state of the outlet, enabling real-time monitoring and alarm functions.

[0064] Circuit Coordination and Usage: In practical use, circuit parameters can be set and optimized according to the environment. For example, a DC-DC boost / buck converter can be added to the power processing module to provide a stable operating voltage under different water flow intensities. When the water flow is very small, the generated voltage is low, and a boost circuit can be used to increase it to the voltage level required by the main control and wireless modules; when the water flow is large, a voltage regulator circuit is used to prevent overvoltage. The main control program is set with threshold judgment conditions: for example, using a small backup battery as an auxiliary, when the energy storage capacitor voltage is detected to be higher than, for example, a 3V threshold and there is continuous flow, the wireless transmission module is automatically started and connected to the network to send data; conversely, when there is no flow for a long time and the energy storage capacitor voltage drops below a predetermined level, the system automatically shuts down the wireless function and enters sleep mode, retaining only low-power monitoring to save energy. This working mode ensures that the device will not frequently report false alarms when the water flow is extremely small, but can respond and upload data in a timely manner once significant flow occurs. Through the above design, this embodiment achieves stable and reliable monitoring of flow conditions in conventional liquid pipelines, without the need for external power supply, achieving the purpose of self-powered and wireless detection.

[0065] Example 2: Self-Powered Liquid Flow Sensing Device Based on Flexible Piezoelectric Power Generation This embodiment provides a self-powered sensing device that uses flexible piezoelectric materials to collect liquid flow energy and detect flow, suitable for narrow pipes or situations requiring distributed monitoring.

[0066] Structural Composition: The core energy harvesting element of this device is a flexible piezoelectric material (such as a polymer thin-film piezoelectric sheet or a piezoelectric ceramic sheet), one end of which is fixed to the inner wall of the pipe, while the other end extends freely into the liquid flow channel. During liquid flow, the piezoelectric sheet is repeatedly bent and vibrated by the fluid impact, thereby generating charge accumulation and alternating voltage output. Electrodes from both ends of the piezoelectric element are connected to a power processing module, including a rectifier circuit and a voltage regulator circuit, which convert the alternating electrical signal generated by the piezoelectric element into direct current and stabilize the voltage. The regulated electrical energy is also used to power the main control module and the wireless transmission module of this device. Since piezoelectric power generation is significantly affected by instantaneous fluid impact, a small-capacity energy storage element (such as a supercapacitor or a micro-rechargeable battery) can be added to the power module to smooth power output and maintain circuit operation during intermittent flow. In addition to the energy harvesting section, the device also includes a detection module and a wireless transmission module, which are managed by the main control module similarly to Embodiment 1.

[0067] Working principle: When liquid flows through the piezoelectric element in the pipe, it causes repeated bending deformation, and the piezoelectric material directly converts mechanical vibration into electrical energy output. As long as liquid flows within the pipe, the piezoelectric element will continuously generate charge and provide voltage, achieving long-term self-sustaining power supply to subsequent circuits. Simultaneously, the characteristics of the piezoelectric element's output electrical signal (such as voltage amplitude and frequency) are closely related to the fluid flow velocity and turbulence: the greater the flow velocity, the greater the vibration amplitude and frequency of the piezoelectric element, and the corresponding increase in output voltage or the appearance of specific fluctuation patterns. Therefore, in this embodiment, the piezoelectric output signal itself can be used to reflect the liquid flow state. For example, the main control module directly acquires the rectified and regulated piezoelectric voltage waveform, and analyzes its amplitude and frequency changes through algorithms to determine changes in flow velocity or the presence of liquid flow. When the flow rate reaches a set threshold or a change in state is detected, the MCU triggers the wireless module to send corresponding data. Since the sensor and generator in the piezoelectric scheme are the same element (the piezoelectric element itself), the structure is simpler and more compact, enabling the acquisition of flow signals while ensuring power supply. This solution features small and simple devices that can be used as disposable sensing elements, making it ideal for environmental monitoring where wiring is difficult or sensors need to be replaced frequently.

[0068] Circuit Coordination and Wireless Communication: The voltage generated by the piezoelectric power generation module typically fluctuates drastically with flow velocity vibrations. Therefore, the power supply module should be designed with appropriate circuit protection and energy management. For example, in cases of large flow velocity fluctuations, a full-bridge rectifier combined with a Zener diode or low-dropout voltage regulator chip can be used to ensure that the voltage output to the MCU remains stable within a safe range. Since the piezoelectric element can output a high open-circuit voltage but has limited drive current, a high-input-impedance energy management chip can be selected to improve energy harvesting efficiency. The operation of the main control module and the wireless module is similar to that in Example 1, both employing a low-power strategy: that is, entering sleep mode as much as possible when there is no flow or a weak signal, retaining only necessary monitoring; once the piezoelectric output voltage indicates significant flow, the system is awakened to collect data and report it. Wireless transmission can use short-range Bluetooth or medium-to-long-range LoRa, etc., with the network configured according to application requirements. For applications requiring large-area coverage, multiple such piezoelectric sensing devices can be distributed as a sensor array, with each node having independent self-powering capabilities, and data can be transmitted to a centralized gateway via wireless networking. This multi-point array monitoring method can cover long pipelines or complex pipe networks, enabling comprehensive perception of the liquid flow status of the entire system.

[0069] Example 3: Self-Powered Liquid Flow Sensing Device Based on Triboelectric Nanogenerator This embodiment provides a sensing device that uses a triboelectric nanogenerator (TENG) to collect water flow energy and detect flow signals, featuring high-sensitivity detection and waterproof sealing.

[0070] Structural Composition: The device comprises an outer shell, inside which a magnetically coupled rotating assembly, a triboelectric nanogenerator assembly, and a magnetic drive component are mounted perpendicularly to the liquid flow channel. The outer shell is fixed to the water outlet of the pipe via an adapter interface, allowing a portion of its interior to communicate with the liquid flow channel. The magnetically coupled rotating assembly consists of an outer rotor and an inner shaft: the outer rotor is located in the flow channel and rotates as water flows through it; the inner shaft is located within a sealed cavity, with a permanent magnet (i.e., the magnetic drive component) mounted near the cavity wall, rotating synchronously with the outer rotor via magnetic coupling. Within the sealed cavity, the triboelectric nanogenerator assembly includes a stator fixed to the inner wall of the cavity and a rotor mounted on the inner shaft. The opposing surfaces of the stator and rotor are each composed of a friction layer made of two different materials. When the inner shaft is magnetically driven to rotate, the rotor friction layer slides against the stator friction layer, generating periodic charge separation and alternating current output. The entire TENG generator assembly is sealed within the internal cavity, isolated from the liquid medium, preventing electrode moisture or material aging, and improving the device's waterproofness and reliability. The output of the power generation component is connected to the power processing module via wires for rectification and energy storage. Similar to the previous embodiment, its output voltage is regulated before powering the main controller and wireless module. Furthermore, a dedicated detection module can be integrated within the device to sense more subtle flow characteristics. However, the TENG output signal itself typically reflects flow velocity changes, so the main controller can directly utilize this signal as a monitoring data source.

[0071] Working Principle: When water flows through the pipe section equipped with this device, it drives the external rotating component to rotate, which in turn drives the TENG rotor inside the sealed cavity to rotate synchronously via magnetic coupling. Since the stator remains stationary, the friction layer on the rotor surface slides tangentially relative to the stator friction layer, generating triboelectric charging every certain angle, resulting in a high-amplitude pulse voltage output between the two poles of the TENG. This triboelectric nano-power generation process not only generates electrical energy to power the circuit but also reflects fluid motion information in the output signal—for example, the frequency of the pulses is related to the rotor speed (i.e., flow velocity), and the pulse amplitude is related to the fluid impact force. Therefore, the main control module can measure the frequency and amplitude of the TENG output pulse signal to accurately calculate the instantaneous flow velocity or detect subtle changes in flow. This solution utilizes the contact separation of double-layer friction materials to collect energy, resulting in high energy conversion efficiency and signal sensitivity, making it particularly suitable for flow monitoring applications requiring high precision and sensitivity. Simultaneously, the use of magnetic drive achieves contactless isolation between the power generation component and the liquid, avoiding the wear and clogging problems caused by long-term immersion in traditional direct-drive rotors, and making the equipment more reliable during long-term underwater operation.

[0072] Circuitry and Communication: The TENG power generation component produces high-voltage, low-current pulsed AC, which needs to be converted to DC by a rectifier circuit (such as a high-voltage diode bridge rectifier). A capacitor can be connected for energy storage and output smoothing. Since the TENG outputs a limited amount of charge each time, the power management module can use a charge pump or a boost DC-DC converter to accumulate enough energy for the MCU. When the accumulated voltage reaches the operating threshold, the main control module is triggered to start, reads the most recent pulse signals to calculate the flow rate, and then transmits the data via a wireless module. After transmission, the system enters standby mode, waiting for the capacitor to recharge to the threshold before starting the next cycle. This forms an adaptive sleep / wake-up mechanism: the system automatically controls the MCU's start and stop by monitoring the energy storage capacitor voltage. When the accumulated voltage is sufficient to support operation, the device is triggered to wake up and perform data acquisition and transmission. After completing the task, it enters sleep mode again to wait for the next energy accumulation. This mechanism ensures that the system can still work intermittently and transmit necessary information even with limited energy, thereby maximizing the utilization of the collected energy. The wireless communication method can be selected as needed, similar to Example 1. In practical applications, the TENG material composition and surface area can be adjusted according to the characteristics of the fluid being measured to extend its service life while maintaining sensitivity. Through the above design, this embodiment can detect flow at extremely low flow rates or even trickle flow (because even small rotational frictions generate electrical signals), greatly improving the ability to detect minute flow rates.

[0073] Example 4: Self-Powered Liquid Flow Sensing Device Based on Multi-Source Energy Hybridization This embodiment provides a self-powered sensing device that integrates multiple energy harvesting methods, thereby improving the power supply reliability of the system in variable environments through the complementarity of different energy sources.

[0074] Structural Composition: This device adds an auxiliary energy harvesting module to the existing embodiment 1 or 2. Specifically, the main body of the device is still installed at the pipe outlet, containing a basic water turbine power generation unit (turbine impeller driving an electromagnetic coil) or piezoelectric vibration unit for primary energy harvesting. Other types of power generation components are added externally or internally as supplementary energy sources. For example, several piezoelectric elements or triboelectric nano-power generation units are added to the impeller-driven power generation structure; these additional elements also generate electrical energy output when water flow impacts the device or causes pipe wall vibration. Alternatively, a small solar photovoltaic panel can be installed on the top of the device's casing to collect solar energy when the device is exposed to the outdoor environment. Another example is the integration of a micro-thermal difference power generation module, which provides electrical energy when there is a temperature difference between the inside and outside of the pipe. The output of all these energy sources is connected to the multi-channel power management circuit equipped in the main control module. The power management module includes multiple input interfaces and corresponding rectification and power control units, which can automatically switch or connect multiple energy sources in parallel according to the power supply status of each energy source, simultaneously charge the energy storage unit, and provide a stable voltage to the main control and other modules. The main control module runs energy management algorithms, such as Maximum Power Point Tracking (MPPT), to optimize the harvesting efficiency of each energy source and intelligently distribute the load among multiple sources, ensuring continuous and stable power supply to the system. Specifically, the main control unit can periodically monitor the voltage and current changes of each energy input and adjust the operating parameters of the power management circuit to ensure that each energy source operates at its maximum power output point, thereby achieving maximum power point tracking control of different energy sources and improving overall energy utilization.

[0075] Working Principle: This embodiment achieves full utilization and complementarity of environmental energy by combining multiple energy harvesting methods. On the one hand, when the water flow is sufficient, the water turbine or piezoelectric module can provide the main power; if the water flow is unstable or even intermittent, the system can rely on other energy sources (such as solar energy and thermoelectric power) to provide auxiliary power, avoiding equipment shutdown due to the interruption of a single energy source. For example, at night when there is no light and the water flow is slow, the piezoelectric element can still obtain a small amount of energy from weak pipe vibrations to maintain basic functions; during the day, the solar module supplements the system with power when there is sunlight. Furthermore, when the water flow stops but there are occasional water hammer pulses or environmental vibrations in the pipe, the piezoelectric or TENG element can capture this energy and generate electricity. The complementarity of multiple energy sources allows the system to maintain a minimum operating state even under extreme conditions, and will not completely fail due to the lack of a single energy source. Through the intelligent scheduling of the main control module, each energy source performs its function under different conditions: water flow energy is the main source, and other energy sources are auxiliary sources. When the main energy source is sufficient, priority is given to energy storage; when the main energy source is insufficient, it is promptly supplemented by auxiliary sources. This design greatly improves the reliability of power supply and the stability of long-term equipment operation.

[0076] Circuitry and Communication: The circuit design of multi-source hybrid devices requires attention to the compatibility and protection of different energy inputs. The power management module must prevent mutual interference between different energy sources, for example, by isolating each input through diodes to prevent high voltage from one input from flowing back to other power modules. The main control program has power priority and switching logic settings. For example, when the voltage of the hydroelectric generator is detected to be below a threshold and the solar energy voltage is sufficient, the system automatically switches to power from the solar module; otherwise, it prioritizes hydroelectric power generation while simultaneously charging the solar module's battery. Apart from the power supply section, the monitoring and wireless transmission sections are basically similar to the aforementioned embodiments: the main control module is periodically or based on events to collect the current status of each energy source and flow sensor data, and transmits this data to the backend via a wireless module. The backend receives not only fluid flow information but also status information such as the current power source and remaining energy reserves, facilitating a comprehensive understanding of the equipment's operating status by administrators. By effectively combining multiple energy sources, this embodiment is very suitable for liquid monitoring applications in complex on-site environments where power supply is affected by various factors, such as unattended water flow monitoring stations in the field. During the rainy season, it mainly uses water flow to generate electricity, while during the dry season it relies on solar energy and wind power generation, ensuring uninterrupted monitoring capabilities 365 days a year.

[0077] In summary, this invention elucidates the structure and operation method of a self-powered wireless liquid flow sensing device through different embodiments. Each embodiment utilizes the liquid flow itself as an energy source to achieve self-powered operation of the sensor nodes and remotely transmits the flow status wirelessly. Depending on specific application requirements, different schemes such as turboelectromagnetic power generation, piezoelectric power generation, triboelectric nanogenerators, or a combination of multiple energy sources can be selected to achieve optimal energy utilization and monitoring effects. This invention possesses good inventiveness and practicality; the disclosed embodiments fully demonstrate its feasibility and can provide a novel and efficient liquid flow monitoring solution for related fields.

[0078] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the inventive concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the protection scope of the present invention.

Claims

1. A passive flow monitoring system with or without water, comprising: The detection end installed at the liquid outlet and the receiving end arranged at the remote end are characterized in that: The detection end comprises: The power generation module comprises a impeller assembly and an electromagnetic generator, the impeller assembly is driven to rotate by the liquid flow and generates electric energy through the electromagnetic generator; The power supply processing module is electrically connected with the power generation module, rectifies, stores and stabilizes the electric energy output by the power generation module, and provides a stable power supply to the subsequent circuit; The main control module is connected with the power supply processing module for power supply, receives the signal of the detection module, and controls the wireless transmission module to work; The detection module detects the rotation parameters of the impeller assembly to obtain the liquid flow information, and transmits the liquid flow information to the main control module; The wireless transmission module is connected with the main control module, and sends the liquid flow information to the receiving end through Bluetooth, WiFi or LoRa wireless communication; The receiving end comprises a wireless receiving module, a receiving end main control module and a user interface; wherein the wireless receiving module is used to receive the liquid flow information sent by the wireless transmission module, the receiving end main control module is used to process the received liquid flow information, and the user interface is used to output the liquid flow information to the user.

2. The passive water flow monitoring system according to claim 1, wherein: The power generation module comprises an electromagnetic generator integrated with the impeller assembly, a permanent magnet is installed on the rotating shaft of the impeller assembly, and an electromagnetic coil is arranged outside the impeller assembly, when the liquid flow drives the impeller assembly to rotate, the permanent magnet moves relative to the electromagnetic coil to generate current.

3. The passive water flow monitoring system according to claim 1, wherein: The power supply processing module comprises a rectifier circuit, an energy storage element and a voltage stabilizing circuit; The rectifier circuit converts the alternating current output by the power generation module into direct current, the energy storage element stores the electric energy, and the voltage stabilizing circuit outputs stable direct current for the main control module and the wireless transmission module.

4. The passive water flow monitoring system according to claim 1, wherein: The detection module comprises a rotating speed sensor; the rotating speed sensor detects the rotating speed of the impeller assembly to obtain the liquid flow information; the rotating speed sensor is selected from a Hall sensor or a photoelectric sensor.

5. The passive water flow monitoring system according to claim 1, wherein: The user interface of the receiving end comprises at least one of a display screen, an audible and visual alarm or a wireless communication interface; when the receiving end main control module judges that the liquid flow information is abnormal, including that the flow rate exceeds the preset threshold or there is no flow for a long time, the audible and visual alarm can trigger an alarm, or the abnormal information can be pushed to a remote terminal through the wireless communication interface.

6. The passive water flow monitoring system according to claim 1, wherein: The detection end further comprises a flexible piezoelectric power generation module, which comprises a section of flexible piezoelectric material fixed to the inner wall of the liquid flow channel and extending into the flow channel. When the liquid flows, the flexible piezoelectric material vibrates and generates electric energy. The output of the flexible piezoelectric power generation module is connected to the power supply processing module after rectification to provide power for the detection end.

7. The passive water flow monitoring system according to claim 1, wherein: The detection end further comprises a triboelectric nanogenerator module, which comprises a stator friction layer and a rotor friction layer arranged oppositely, and a magnetic coupling transmission component connected to the rotor friction layer. When the liquid flows and drives the magnetic coupling transmission component to rotate, the rotor moves relative to the stator and generates electric energy. The output of the triboelectric nanogenerator module is connected to the power supply processing module after rectification.

8. The passive water flow monitoring system according to claim 1, wherein: The detection end further comprises an auxiliary energy harvesting module, which comprises at least one solar photovoltaic panel and at least one thermoelectric generator element. The solar photovoltaic panel is arranged on the outer surface of the detection end to harvest light energy. The thermoelectric generator element converts environmental temperature difference into electric energy. The output of the auxiliary energy harvesting module is connected to the power supply processing module. The main control module is provided with a plurality of power management circuits, which automatically switch different energy inputs according to the energy input situation to maintain stable power supply.

9. The passive water flow monitoring system according to claim 1, wherein: The power generation module is a multi-stage composite power generation structure, which comprises a plurality of impellers arranged on the same shaft, and a plurality of electromagnetic coils corresponding to each level of impeller, or a multi-phase electromagnetic winding coil arranged on the same impeller assembly, thereby widening the applicable flow rate range of the device and improving the power generation efficiency under low flow rate conditions.

10. The passive water flow monitoring system according to claim 1, wherein: The main control module and the wireless transmission module of the detection end adopt a low-power sleep / wake-up design. When there is no liquid flow, the device enters a sleep state to reduce power consumption. When liquid flow is detected or the preset sleep duration is met, the device automatically wakes up for data collection and transmission.

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