A water leakage detection circuit, device and method

Abstract

The application discloses a water leakage detection circuit, device and method, and relates to the technical field of pipeline water leakage monitoring.The application comprises a signal detection circuit for detecting water pipe leakage; a microcontroller unit electrically connected with the signal detection circuit; and an infrared emission driving circuit electrically connected with the microcontroller unit; wherein the microcontroller unit controls the infrared emission driving circuit to emit an infrared alarm signal containing a fixed address code according to the output signal of the signal detection circuit.The application has the beneficial effect that the water leakage signal is triggered by an AD logic level of a high-resistance voltage divider comparator circuit, and the application has strong anti-strong electromagnetic interference capability; the whole machine standby current is controlled within 2 mu A by matching an ultra-low-power LDO power supply and a transistor infrared amplification driving circuit, and the application can output an infrared signal with address coding without external power supply and communication lines, and is stable and adaptive to unattended scenes in a valve hall.

Description

Technical Field

[0001] This invention relates to the field of pipeline leakage monitoring technology, and in particular to a leakage detection circuit, device and method. Background Technology

[0002] Flexible low-frequency AC power transmission is a core technology for solving the problem of new energy consumption and long-distance transmission of offshore wind power. The AC frequency conversion valve is its core equipment, and the heat generated during operation is dissipated through a closed-loop water circulation cooling system. The valve section structure of the AC frequency conversion valve is similar to that of the DC converter valve, and the sealing of the PVDF (polyvinylidene fluoride) cooling water pipes within the valve section directly determines the system safety.

[0003] Currently, the industry mainly uses four types of solutions for monitoring leaks in valve hall cooling water pipes: First, system-level flow difference detection, which judges overall leakage based on the difference in inlet and outlet water flow in the main circuit; second, centralized water accumulation detection, which involves placing detection ropes or electrodes on the floor of the valve hall and at the bottom of the valve tower, triggering an alarm based on the conductivity of accumulated water; third, wired point detection, which involves installing sensors at leak-prone points and transmitting signals via cables; and fourth, manual inspection after shutdown, which involves visually checking for leaks and condensation.

[0004] However, long-term operation and maintenance revealed several shortcomings in these solutions: flow difference and water accumulation detection only trigger alarms when leakage accumulates to a certain level, failing to detect minor leaks early and delaying intervention. In severe cases, this can lead to decreased insulation of the switching frequency valves or even unplanned shutdowns. Furthermore, these two solutions can only assess overall system leakage, failing to pinpoint specific faulty valve sections or pipes. Manual inspections after shutdown cannot achieve real-time monitoring during operation, and the dense piping layout with numerous blind spots results in low inspection efficiency. Additionally, the high voltage and strong electromagnetic interference conditions in the valve hall complicate wired detection installation, cause signal distortion, and pose insulation safety hazards. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is that the existing converter valve cooling water pipe leakage detection has a strong lag and it is difficult to accurately locate the leakage point.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a water leakage detection circuit, which includes a signal detection circuit for detecting water pipe leakage; The microcontroller unit is electrically connected to the signal detection circuit; An infrared emission driving circuit is electrically connected to the microcontroller unit; The microcontroller unit controls the infrared emission driving circuit to emit an infrared alarm signal containing a fixed address code based on the output signal of the signal detection circuit.

[0007] As a preferred embodiment of the leakage detection circuit of the present invention, the signal detection circuit includes a comparator, a pull-up resistor electrically connected to the non-inverting input terminal of the comparator, and a voltage divider resistor connected to the inverting input terminal of the comparator. The voltage divider resistor provides a fixed threshold voltage for the signal detection circuit.

[0008] As a preferred embodiment of the leakage detection circuit of the present invention, a first probe is connected between the non-inverting input terminal of the comparator and the pull-up resistor; A second probe is connected between the voltage divider resistor and the ground. The first probe and the second probe are spaced apart.

[0009] In a preferred embodiment of the leakage detection circuit of the present invention, the output terminal of the comparator is directly connected to the input pin of the microcontroller unit. The microcontroller unit is configured as follows: When the output of the comparator is high, the microcontroller unit is in standby mode. When the output of the comparator is low, the microcontroller unit is in a woke-up working state.

[0010] In a preferred embodiment of the leakage detection circuit of the present invention, the output pin of the microcontroller unit is connected to the infrared emission driving circuit. The infrared emission driving circuit includes a transistor, a base resistor connected to the base of the transistor, a current-limiting resistor connected in series with the collector of the transistor, and a light-emitting diode. The emitter of the transistor is grounded.

[0011] In a preferred embodiment of the leakage detection circuit of the present invention, the transistor is configured such that when no current flows through the base of the transistor, the collector and emitter are disconnected, and the light-emitting diode is turned off. When current flows through the base of the transistor, the collector and emitter close, and the light-emitting diode is activated.

[0012] In a preferred embodiment of the leakage detection circuit of the present invention, the reset pin of the microcontroller unit is indirectly connected to the power supply.

[0013] In a preferred embodiment of the leakage detection circuit of the present invention, the microcontroller unit is connected in series between the power supply and ground via two pins.

[0014] The beneficial effects of the leakage detection circuit of the present invention are as follows: This circuit realizes the leakage signal without AD logic level triggering through a comparator circuit with high impedance voltage division, and has strong anti-electromagnetic interference capability; with ultra-low power LDO power supply and transistor infrared amplification drive circuit, the standby current of the whole machine is controlled within 2μA, no external power supply and communication line are required, and it can output infrared signal with address encoding, which is stably adapted to the unattended valve hall scenario.

[0015] Another objective of this invention is to provide a leak detection device that addresses the problems of existing leak detection devices requiring modifications to the original pipeline structure, complex wiring, and inability to achieve accurate positioning.

[0016] To solve the above-mentioned technical problems, the present invention also provides the following technical solution: a water leakage detection device, which includes a water leakage detection circuit; and a clamp, which is snapped onto the outside of the pipe connection, wherein a water collection groove is formed at the bottom of the clamp; The water collection tank has a recess inside that accommodates the first probe and the second probe; When the recess is filled with water, a passage is formed between the first probe and the second probe.

[0017] The beneficial effects of the leakage detection device of the present invention are as follows: the device does not require modification of the original pipeline structure through the clamping fixture, and the throttling and slow-draining structure can filter interference such as condensation and splashing water; the built-in hierarchical detection circuit and low-power core circuit can identify different leakage conditions, and achieve accurate positioning by multiplexing the existing camera in the valve hall through infrared encoded signal, which eliminates the need for wiring, resists strong electromagnetic interference, and is suitable for the stringent operation and maintenance requirements of the converter valve.

[0018] Another objective of this invention is to provide a water leakage detection method that addresses the problems of existing water leakage detection methods being unable to simultaneously achieve long-term operation with ultra-low power consumption at the nanoampere level, inaccurate water leakage triggering, and accurate water leakage location.

[0019] To solve the above-mentioned technical problems, the present invention also provides the following technical solution: a water leakage detection method, which includes a water leakage detection circuit; when water leakage occurs at the water pipe joint, the first probe and the second probe form a passage through water; At this time, the voltage at the non-inverting input terminal of the comparator is less than the threshold voltage at the inverting input terminal, and the comparator outputs a low-level signal. The microcontroller unit is activated upon receiving a low-level signal and flows current into the base of the transistor; When current is applied to the base of a transistor, the collector and emitter of the transistor form a closed loop to ground. The circuit containing the light-emitting diode is closed, and the power supply provides power to the light-emitting diode and ensures that the light-emitting diode continues to emit light. Infrared cameras deployed in the factory area capture light source signals, and the specific location of pipeline leaks is determined based on fixed infrared coding information.

[0020] The beneficial effects of the water leakage detection method of the present invention are as follows: it achieves ultra-low power consumption at the nanoampere level through deep sleep, realizes rapid wake-up of water leakage events by switching the fixed threshold level, generates an infrared coded signal with a unique address and water leakage level to complete the alarm, automatically resets to sleep after transmission, resists strong electromagnetic interference throughout the process, and takes into account both ultra-long standby life and the accuracy of water leakage detection and positioning. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A connection diagram of the signal detection circuit is shown; Figure 2 The pinout diagram of the microcontroller unit is shown; Figure 3 A connection diagram of the infrared emission driving circuit is shown; Figure 4 A schematic diagram of the connection structure of the power management unit is shown; Figure 5 A topology diagram of the leak detection device is shown; Figure 6 A schematic diagram of the leak detection device is shown.

[0023] In the diagram: 1. Signal detection circuit; 11. Comparator; 12. Pull-up resistor; 13. Voltage divider resistor; 14. First probe; 15. Second probe; 2. Microcontroller unit; 3. Infrared emission drive circuit; 31. Transistor; 32. Base resistor; 33. Current limiting resistor; 34. Light-emitting diode; 4. Fixture; 41. Water collection tank. Detailed Implementation

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] The terminology used in this invention is that which is currently widely used in the art in consideration of the function of the invention; however, these terms may vary according to the intent of those skilled in the art, precedent, or new technology in the art. Furthermore, specific terms may be chosen by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the invention. Therefore, the terms used in this specification should not be construed as simple names, but rather based on their meanings and the overall description of the invention.

[0026] Reference Figures 1 to 3 This embodiment provides a water leakage detection circuit, including a signal detection circuit 1 for detecting water pipe leakage; a microcontroller unit 2 electrically connected to the signal detection circuit 1; and an infrared emission drive circuit 3 electrically connected to the microcontroller unit 2. The microcontroller unit 2 controls the infrared emission drive circuit 3 to emit an infrared alarm signal containing a fixed address code according to the output signal of the signal detection circuit 1.

[0027] In this embodiment, the signal detection circuit 1 is used to receive the water leakage signal from the pipe and convert the water leakage signal into an electrical signal, which is then transmitted to the microcontroller unit 2.

[0028] Specifically, the signal detection circuit 1 outputs two different voltage signals so that the microcontroller unit 2 can perform corresponding actions by converting the two voltage signals. When there is no water leakage in the pipe, the signal detection circuit 1 outputs a high-level signal; conversely, when there is water leakage in the pipe, the signal detection circuit 1 outputs a low-level signal.

[0029] In this embodiment, the microcontroller unit 2 is configured to operate in two modes: a deep sleep mode and a wake-up mode. When a high-level signal is received from the signal detection circuit 1, the microcontroller unit 2 is in a standby (deep sleep) mode, at which time the power supply provides the energy required to maintain the standby mode.

[0030] When the microcontroller unit 2 receives a low-level signal from the signal detection circuit 1, the microcontroller unit 2 is woken up and enters the working mode.

[0031] After the microcontroller unit 2 is woken up, it outputs current to drive the infrared transmitting drive circuit 3 and causes it to emit an infrared alarm signal containing a fixed address code; this infrared signal is used to issue a warning to the staff to inform them that there is a water leak in the pipeline.

[0032] Specifically, staff can quickly locate pipeline leaks using fixed address codes in infrared signals, enabling timely repairs and maintenance. Through fixed address codes, staff can immediately understand the leakage situation in the early stages of a pipeline leak and accurately determine the leak location using the coded address, facilitating rapid repairs and maintenance to ensure the unit operates stably for a long time and reduce potential risks.

[0033] Reference Figure 1 As an optional embodiment, the signal detection circuit 1 includes a comparator 11, a pull-up resistor 12 electrically connected to the non-inverting input terminal of the comparator 11, and a voltage divider resistor 13 connected to the inverting input terminal of the comparator 11; the voltage divider resistor 13 provides a fixed threshold voltage for the signal detection circuit 1.

[0034] In this embodiment, comparator 11 is preferably selected as a model with extremely low quiescent current; comparator 11 is connected in series between the power supply and ground.

[0035] It should be noted that the pull-up resistor 12 is a high-resistance resistor of 10MΩ, which pulls the non-inverting input of comparator 11 to a high level in the dry state; at the same time, the high resistance also minimizes the static current when water leaks.

[0036] Specifically, pull-up resistor 12 is connected in series between the power supply and the non-inverting input of comparator 11.

[0037] Furthermore, the voltage divider resistor 13 forms a reference voltage source, providing a fixed threshold voltage to the inverting input of comparator 11.

[0038] Preferably, there are two voltage divider resistors 13, and the two voltage divider resistors 13 are connected in series between the power supply and the ground. The connection node between the two voltage divider resistors 13 is connected to the inverting input terminal of the comparator 11. The pull-up resistor 12 and the voltage divider resistors 13 are both powered by the power supply, forming two independent voltage divider paths.

[0039] The connection node between the two voltage divider resistors 13 is connected to the inverting input terminal of the comparator 11; a fixed threshold voltage is provided to the inverting input terminal of the comparator 11 through the two voltage divider resistors 13.

[0040] For example, when the resistance values ​​of the two voltage divider resistors 13 are the same as those of the pull-up resistor 12, the threshold voltage at the inverting input of comparator 11 is half of the power supply voltage; at this time, the non-inverting input voltage is greater than the threshold voltage at the inverting input, the output of comparator 11 is high, and the microcontroller unit 2 is in a silent state.

[0041] When the non-inverting input voltage is less than the threshold voltage of the inverting input, the comparator 11 outputs a low level, and the microcontroller unit 2 is in working state.

[0042] Alternatively, the voltage divider resistor 13 can also be a single resistor, but it needs to be supplied with a fixed external power supply to ensure that the voltage divider resistor 13 can maintain a fixed voltage.

[0043] Of course, the voltage divider resistor 13 can also be used to divide multiple voltages in series to obtain a specific ratio reference voltage; the threshold can be adjusted by adjusting the resistance.

[0044] Furthermore, a first probe 14 is connected between the non-inverting input terminal of comparator 11 and the pull-up resistor 12; a second probe 15 is connected between the inverting input terminal of comparator 11 and the voltage divider resistor 13; the first probe 14 and the second probe 15 are spaced apart.

[0045] It should be noted that the first probe 14 and the second probe 15 have the same structure, which is an exposed printed circuit board pad or a metal probe. The first probe 14 and the second probe 15 are spaced 5mm to 10mm apart.

[0046] Specifically, the first probe 14 is connected at the connection node between the non-inverting input of the comparator 11 and the pull-up resistor 12; the second probe 15 is connected to ground.

[0047] When in a dry state, the first probe 14 and the second probe 15 are separated by air, and the resistance is close to infinite; the voltage at the non-inverting input of the comparator 11 is the same as the power supply voltage.

[0048] When the power supply voltage is 3.3V, the voltage at the non-inverting input of comparator 11 is 3.3V; while the voltage at the inverting input of comparator 11 is 1.65V (when the two voltage divider resistors 13 have the same resistance).

[0049] When the first probe 14 and the second probe 15 form a path through the leaking water, the resistance between the first probe 14 and the second probe 15 is much smaller than the resistance of the pull-up resistor 12, causing the voltage at the non-inverting input of the comparator 11 to approach 0V, thus forming a voltage conversion from high level to low level.

[0050] Reference Figures 1 to 2 In one embodiment of the present invention, the output terminal of comparator 11 is directly connected to the input pin of microcontroller unit 2; microcontroller unit 2 is configured such that when the output terminal of comparator 11 outputs a high level, microcontroller unit 2 is in a standby state; and when the output terminal of comparator 11 outputs a low level, microcontroller unit 2 is in a woke-up working state.

[0051] It should be noted that the input pins of microcontroller unit 2 are configured for falling edge triggering mode. When the pipeline is in a dry state, the resistance between the first probe 14 and the second probe 15 is extremely high (>100MΩ), and the voltage at the non-inverting input terminal is equal to the power supply voltage; since the voltage at the non-inverting input terminal is greater than the voltage at the inverting input terminal, comparator 11 outputs a high level.

[0052] When there is a water leak, the resistance of the water is connected between the first probe 14 and the second probe 15. At this time, the pull-up resistor 12 and the resistance of the water form a voltage divider. Since the resistance of the pull-up resistor 12 is much greater than the resistance of the water, the voltage at the non-inverting input terminal will be much lower than the voltage at the inverting input terminal, and the output of comparator 11 flips to a low level.

[0053] The input pins of microcontroller unit 2 are configured to be triggered by a falling edge; when the signal at the output of comparator 11 changes from high to low, microcontroller unit 2 is awakened from deep sleep and begins to execute the alarm program.

[0054] Specifically, the microcontroller unit 2 is preferably the MSP430FR2355; this series of microcontroller units 2 is based on FRAM (ferroelectric random access memory) storage technology, has ultra-low power consumption characteristics (current can be less than 500nA in standby mode), fast wake-up time (from standby to active <10µs), wide operating voltage (such as 1.8V-3.6V), and integrates a feature-rich timer (for generating pulse width modulation signals).

[0055] When the microcontroller unit 2 is in standby mode, the internal current of the system is mainly composed of the static current (150nA) of the comparator 11 and the current of the voltage divider resistor 13. If the voltage divider resistor 13 is set to 10MΩ and the power supply voltage is 3V, then this part of the current is 300nA. The total standby current is only in the hundreds of nanoamps, which is extremely small.

[0056] When a leak occurs, assuming the pull-up resistor 12 is 10MΩ and the water resistance is 100kΩ, the current flowing through the pull-up resistor 12 and the first probe 14 and the second probe 15 is only 0.3µA. This design meets the requirements of ultra-low power consumption and can continuously stand by with a current at the nanoamp level.

[0057] Reference Figures 1 to 3 In some embodiments, the output pin of the microcontroller unit 2 is connected to the infrared emission driving circuit 3; the infrared emission driving circuit 3 includes a transistor 31, a base resistor 32 connected to the base of the transistor 31, a current-limiting resistor 33 connected in series with the collector of the transistor 31, and a light-emitting diode 34; the emitter of the transistor 31 is grounded.

[0058] It should be noted that transistor 31 is preferably an NPN bipolar junction transistor (a three-layer, two-junction (two PN junctions) semiconductor device consisting of two layers of N-type semiconductor material sandwiching a layer of P-type semiconductor material; these three layers lead out three electrodes respectively: emitter, base, and collector). The base is connected to a base resistor 32, which protects the output port of the microcontroller unit 2 and provides a suitable base current to transistor 31 to enable it to saturate and conduct.

[0059] Specifically, LED 34 is preferably an infrared LED, and a model suitable for remote control applications can be selected.

[0060] Furthermore, transistor 31 is configured such that when no current flows through the base of transistor 31, the collector and emitter are cut off, and the light-emitting diode 34 is off; when current flows through the base of transistor 31, the collector and emitter are saturated and turned on, and the light-emitting diode 34 is lit.

[0061] It should be noted that when a water leak occurs, the output of comparator 11 goes low, and microcontroller unit 2 is woken up. After being woken up, the external interrupt trigger signal from the output of comparator 11 to microcontroller unit 2 is first blocked to prevent it from being triggered repeatedly during the alarm period.

[0062] Then, microcontroller unit 2 starts a timer to output a 38kHz carrier wave at the output terminal; at the same time, the duration of the carrier wave is precisely controlled by software delay or another timer to form coded "pulses" and "gap".

[0063] To ensure successful reception at the receiving end, the entire data frame is repeatedly transmitted 3 to 5 times, with an interval of 100ms each time. After all transmission tasks are completed, the external interrupt function from the output of comparator 11 to microcontroller unit 2 is re-enabled, and then microcontroller unit 2 is put back into deep sleep mode.

[0064] Furthermore, transistor 31 is configured such that when no current flows through the base of transistor 31, the collector and emitter are disconnected, and the light-emitting diode 34 is off; when current flows through the base of transistor 31, the collector and emitter are saturated and conducting, and the light-emitting diode 34 is lit.

[0065] It should be noted that the base resistor 32 is connected in series between the microcontroller unit 2 and the base of the transistor 31. Under normal conditions, the collector and emitter of the transistor 31 are disconnected. When the microcontroller unit 2 is woken up, the corresponding output current flows through the base of the transistor 31, and the collector and emitter of the transistor 31 are turned on, forming a closed path from the power supply to ground.

[0066] At this time, the light-emitting diode 34 is connected in series between the power supply and the ground. The transistor 31 acts as a switch. When current flows through the base of the transistor 31, the collector and emitter of the transistor 31 are turned on, which makes the light-emitting diode 34 in a closed circuit and cause it to emit light.

[0067] Furthermore, the reset pin of microcontroller unit 2 is indirectly connected to the power supply.

[0068] It should be noted that the reset pin of microcontroller unit 2 is connected to VCC through a pull-up resistor 12 and a capacitor to ground to provide a reliable power-on reset.

[0069] Furthermore, the microcontroller unit 2 is connected in series between the power supply and ground via two pins.

[0070] Specifically, "no AD" emphasizes that this triggering process does not involve sending a continuously changing analog signal to an analog-to-digital converter to convert it into digital code, then having the processor determine whether the code value reaches a certain threshold before finally generating a trigger signal.

[0071] Reference Figure 4 In some embodiments, a power management unit is also included to maintain stable power output; the power management unit includes a battery Bt1, a power switch SW1, a low dropout linear regulator U2, an input capacitor C1, and an output capacitor C2.

[0072] The positive terminal of battery Bt1 is electrically connected to the first terminal of power switch SW1. The second terminal of power switch SW1 is also electrically connected to the input pin VIN of low dropout linear regulator U2 and the first terminal of input capacitor C1. The negative terminal of battery Bt1 is also electrically connected to the ground pin GND of low dropout linear regulator U2, the second terminal of input capacitor C1, the second terminal of output capacitor C2, and system ground. The output pin VOUT of low dropout linear regulator U2 is also electrically connected to the first terminal of output capacitor C2 and system power supply VCC. VCC serves as the power supply bus for the entire leak detection system and is connected to the power input terminals of the leak detection module, infrared signal control module, and infrared signal transmitting module, respectively.

[0073] It should be noted that the power switch SW1 is an optional device. In embodiments where the power switch SW1 is omitted, the positive terminal of the battery Bt1 is directly connected to the input pin VIN of the low dropout linear regulator U2 and the first terminal of the input capacitor C1.

[0074] Battery Bt1 uses a 3V lithium manganese button cell; the nominal voltage of this battery is 3V, the initial open circuit voltage is 3.3V, and as the discharge process proceeds, its terminal voltage slowly decreases from 3.3V to 2V; the CR2032 battery has the characteristics of small size and low self-discharge rate, making it suitable as a power supply for long-term low-power standby systems.

[0075] The power switch SW1 is a single-pole single-throw mechanical switch connected in series with the positive power supply path of the battery Bt1. This power switch is used to completely disconnect the battery Bt1 from the downstream circuit by manual operation during product transportation or long-term non-use, so as to achieve zero power consumption standby and eliminate the power consumption of the battery in non-use scenarios.

[0076] The low-dropout linear regulator U2 is used to convert the unstable input voltage provided by the battery Bt1 into a fixed 2.8V output voltage. The typical quiescent current of the low-dropout linear regulator U2 is 1.6µA. This ultra-low quiescent current characteristic allows the low-dropout linear regulator U2 to generate only microwatts of power consumption in long standby states.

[0077] The input capacitor C1 is a 1µF ceramic capacitor connected between the input pin VIN of the low-dropout linear regulator U2 and ground. It suppresses input voltage fluctuations caused by changes in the internal resistance of the battery Bt1 and provides a stable input source for the LDO (low-dropout linear regulator). Compared to electrolytic capacitors, ceramic capacitors have lower leakage current, which helps reduce the system's static power consumption.

[0078] Output capacitor C2 is a 1µF ceramic capacitor connected between the output pin VOUT of the low-dropout linear regulator U2 and ground. It is used to compensate for the frequency response of the LDO, suppress output ripple, and improve the transient response capability of the load. The specific capacitance values ​​and types of input capacitor C1 and output capacitor C2 are determined according to the recommended parameters in the datasheet.

[0079] Reference manual attached Figure 4 The “EN” pin is explained as follows: It is a digital control signal input pin used to control the operating state of the power module or chip.

[0080] In normal operating mode, after closing the power switch SW1, the 3V DC voltage provided by the battery Bt1 is filtered by the input capacitor C1 and input to the input pin VIN of the low dropout linear regulator U2. The low dropout linear regulator U2 regulates the input voltage and outputs a stable 2.8V voltage at its output pin VOUT. After being filtered by the output capacitor C2, it powers the entire water leakage detection system. As battery Bt1 continues to discharge, its terminal voltage gradually decreases from 3.3V. Due to the low dropout voltage characteristic of MCP1700, VCC can be maintained at a stable 2.8V within the range where the battery voltage drops to about 2.98V. When the battery voltage drops further below the minimum input voltage threshold of LDO, VCC begins to drop, and the system enters an undervoltage state.

[0081] Reference Figure 6 This embodiment provides a water leakage detection device, including a clamp 4, which is snapped onto the outside of the pipe connection. A water collection tank 41 is formed at the bottom of the clamp 4. A recess is formed inside the water collection tank 41 to accommodate a first probe 14 and a second probe 15. When the recess is filled with water, a passage is formed between the first probe 14 and the second probe 15.

[0082] The fixture 4 is manufactured using 3D printing technology and is made of ABS (acrylonitrile-butadiene-styrene copolymer) or photosensitive resin, which has excellent insulation properties, mechanical strength and corrosion resistance. The fixture 4 is an insulated structure as a whole and does not introduce any conductive metal materials, ensuring that there is no risk of electric shock and short circuit in the high potential environment of the valve hall.

[0083] The cross-sectional shape of the clamp 4 is adapted to the outer diameter of the PVDF water pipe to be clamped; specifically, the clamp 4 is formed by two parts, an upper shell and a lower shell, fastened together; the inner side of the upper shell has an arc-shaped concave surface that fits against the outer wall of the PVDF water pipe, and the inner side of the lower shell also has an arc-shaped concave surface that fits against the outer wall of the PVDF water pipe; the upper shell and the lower shell are detachably fastened together by a bolt and nut structure, and after fastening, the whole body wraps around the outer wall of the PVDF water pipe.

[0084] Furthermore, after the upper and lower shells are fastened together, a guide groove is formed circumferentially between their mating surfaces to guide the cooling water seeping from the PVDF water pipe interface to converge into the water collection tank 41 along the guide groove.

[0085] A water collection trough 41 is formed at the bottom of the lower housing and extends along the axial direction of the clamp 4. The cross-section of the water collection trough 41 is U-shaped, and its volume is calculated to be adapted to the typical leakage flow rate of the valve section water pipe, ensuring that leakage water can be effectively collected in the early stage of leakage.

[0086] The water collection tank 41 has a recess inside, which is a locally deepened area at the bottom of the water collection tank 41, used to accommodate the first probe 14 and the second probe 15.

[0087] When the recess is filled with water, a conductive path is formed between the first probe 14 and the second probe 15 through the water film.

[0088] It should be noted that the preferred installation location for clamp 4 is at the interface of the PVDF water pipe, including flange connections, compression fitting connections, and hot-melt butt joints, as water pipe interfaces are the most prone to leakage. Clamp 4 is directly installed on the outer wall of the PVDF water pipe through a snap-fit ​​method, without changing the original pipeline structure or damaging the pipeline's sealing performance. The installation process requires no water outage, welding, or drilling.

[0089] It should be noted that the clamp 4 includes an upper shell and a lower shell. After they are fastened together, a sealing ring groove is formed between the arc-shaped concave surface on the inner side of the two shells and the outer wall of the PVDF water pipe. An O-ring is embedded in the sealing ring groove. The O-ring is made of silicone rubber. When the upper shell and the lower shell are fastened together, the O-ring is pressed tightly against the outer wall of the PVDF water pipe to form an annular sealing surface.

[0090] Specifically, when leakage occurs at the PVDF water pipe interface, the leaked cooling water flows down the outer wall of the PVDF water pipe, is blocked by the O-ring seal above the inner arc concave surface of the upper and lower shells, enters the guide groove, flows along the guide groove to the bottom water collection tank 41, accumulates in the depression, submerges the first probe 14 and the second probe 15, and triggers the leakage detection signal.

[0091] This embodiment further explains the structure and arrangement of the first probe 14 and the second probe 15.

[0092] Both the first probe 14 and the second probe 15 are conductive electrodes fabricated on an insulating substrate. Specifically, both the first probe 14 and the second probe 15 are printed circuit boards with FR-4 epoxy fiberglass board as the substrate. The electrode layer consists of exposed copper pads, and the surface of the copper pads is coated with a gold plating layer or an organic solder mask to improve conductivity and corrosion resistance.

[0093] The printed circuit board probe is embedded in the bottom of the recess and is electrically connected to the signal detection circuit 1 via leads.

[0094] It should be noted that the distance between the first probe 14 and the second probe 15 is 5mm to 10mm. This distance is based on the following considerations: if the distance is too small, residual water droplets or condensation on the inner wall of the fixture 4 may form a path between the two probes, causing false alarms; if the distance is too large, the water film formed by a small amount of leakage water may not be able to effectively submerge the two probes, reducing the detection sensitivity; in this embodiment, the preferred distance is 8mm.

[0095] Furthermore, the first probe 14 and the second probe 15 are connected to the signal detection circuit 1 via leads; the leads are led out from the recessed sidewall, run along the outside of the fixture 4, and connect to the circuit board where the signal detection circuit 1 is located; the leads are flexible flat cables to accommodate the bending requirements of the leads after the fixture 4 is installed.

[0096] Reference Figures 1 to 3 The signal detection circuit 1 includes a comparator 11, a pull-up resistor 12 electrically connected to the non-inverting input terminal of the comparator 11, and a voltage divider resistor 13 connected to the inverting input terminal of the comparator 11; the voltage divider resistor 13 provides a fixed threshold voltage for the signal detection circuit 1.

[0097] Comparator 11 should preferably be a model with extremely low quiescent current. In this embodiment, the TI (Texas Instruments) TLV3691 comparator 11 is selected. The typical quiescent current of this comparator 11 is approximately 150nA, and the operating voltage range is 1.8V to 5.5V, making it suitable for ultra-low power applications. Of course, other low-power comparator 11 products with the same function can also be selected. The VCC pin and GND pin of comparator 11 are connected to the system power supply VCC and system ground, respectively.

[0098] It should be noted that the pull-up resistor 12 is a high-resistance resistor of 10MΩ, connected in series between the system power supply VCC and the non-inverting input of the comparator 11. When there is no water leakage in the dry state, the pull-up resistor 12 pulls the non-inverting input of the comparator 11 to a high level. At the same time, due to the extremely high resistance of the pull-up resistor 12, the static current flowing through the path of the first probe 14 and the second probe 15 is minimized when water leaks.

[0099] The first probe 14 is connected at the connection node between the non-inverting input terminal of the comparator 11 and the pull-up resistor 12. That is, one end of the first probe 14 is electrically connected to the non-inverting input terminal of the comparator 11, and the other end is electrically connected to the end of the pull-up resistor 12 away from the power supply.

[0100] Furthermore, there are two voltage divider resistors 13, namely a first voltage divider resistor and a second voltage divider resistor; the first voltage divider resistor and the second voltage divider resistor are connected in series between the system power supply VCC and the system ground; the connection node between the first voltage divider resistor and the second voltage divider resistor is connected to the inverting input terminal of the comparator 11, providing a fixed threshold voltage to the inverting input terminal of the comparator 11.

[0101] Both the pull-up resistor 12 and the voltage divider resistor 13 are powered by the system power supply VCC, forming two independent voltage divider paths.

[0102] Preferably, the resistance values ​​of the first voltage divider resistor and the second voltage divider resistor are both set to 10MΩ, which is the same as the resistance value of the pull-up resistor 12; when the power supply voltage is 3V, the threshold voltage of the inverting input terminal of the comparator 11 is half of the power supply voltage, i.e., 1.5V.

[0103] The second probe 15 is connected to the system ground and is used in conjunction with the first probe 14 to form a leakage detection path.

[0104] When in a dry state, the first probe 14 and the second probe 15 are separated by air, and the resistance is close to infinite (>100MΩ). The non-inverting input of comparator 11 is pulled up to the power supply voltage (about 3V) through the pull-up resistor 12, while the voltage of the inverting input is half of the power supply voltage, about 1.5V. Since the voltage of the non-inverting input is greater than the voltage of the inverting input, the output of comparator 11 outputs a high level, and the microcontroller unit 2 is in a deep standby sleep mode.

[0105] When the water seepage accumulates in the recess of the water collection tank 41 and submerges the first probe 14 and the second probe 15, a conductive path is formed between the two probes through the water film; the resistance of the water is connected between the first probe 14 and the second probe 15; at this time, the pull-up resistor 12 and the resistance of the water form a voltage divider. Since the pull-up resistor 12 is much larger than the resistance of the water, the voltage at the non-inverting input terminal of the comparator 11 will be much lower than the voltage at the inverting input terminal, and the output of the comparator 11 will flip to a low level.

[0106] Furthermore, the second probe 15 is not directly connected to the system ground, but can be selectively connected to the connection node between the second voltage divider resistor and the system ground; in this way, when water leaks, the water film is connected between the first probe 14 and the second probe 15, and the second probe 15 is grounded through the second voltage divider resistor, so that the influence of the water leakage path on the non-inverting input terminal is more stable.

[0107] To further facilitate understanding, the English symbols present in the accompanying drawings are explained.

[0108] VCC: Represents the live wire (L) of the circuit, which provides positive voltage and is the starting point of current.

[0109] GND: Represents the neutral line (N) of the circuit, which is the end point of the current and has a voltage of 0V.

[0110] P1.0: This indicates pin 0 of port 1, which is a physically existing, wireable metal pin on the microcontroller unit 2 chip. It is directly connected to the output of comparator 11 of signal detection circuit 1.

[0111] P1.1: In the circuit, the first physical pin of the first general-purpose input / output port on the microcontroller unit 2 chip is directly connected to the left end of the base resistor 32 of the infrared emission drive circuit 3.

[0112] RST: The dedicated hardware reset pin of microcontroller unit 2 is pre-installed at the factory, which is equivalent to the restart button of this leak detection equipment.

[0113] Reference Figure 1 and Figure 5 This embodiment provides a water leakage detection method, which includes forming a passage between the first probe 14 and the second probe 15 through water when a water leak occurs at the water pipe joint.

[0114] It should be noted that when water leaks at the PVDF water pipe joint, the seeping cooling water flows down the outer wall of the water pipe, flows through the guide groove of the clamp 4 to the bottom water collection tank 41, and accumulates in the depression at the bottom of the water collection tank 41. When the accumulated water is sufficient to submerge the first probe 14 and the second probe 15 installed in the depression, the first probe 14 and the second probe 15 form a conductive path through the water film.

[0115] At this time, the voltage at the non-inverting input terminal of comparator 11 is less than the threshold voltage at the inverting input terminal, and comparator 11 outputs a low-level signal. Specifically, the pull-up resistor 12 and the equivalent resistance of the water film form a voltage divider circuit, and the voltage at the non-inverting input of comparator 11 is pulled low. Since the equivalent resistance of the water film is much smaller than that of the pull-up resistor 12, the voltage at the non-inverting input approaches 0V, which is less than the threshold voltage (about 1.5V) at the inverting input. The output of comparator 11 flips to a low-level signal.

[0116] The microcontroller unit 2 is activated after receiving a low-level signal and flows current into the base of the transistor 31.

[0117] The input pins of microcontroller unit 2 are directly connected to the output of comparator 11, and the input pins are configured to be triggered by the falling edge.

[0118] When the signal at the output of comparator 11 changes from high level to low level, the falling edge signal triggers an external interrupt of microcontroller unit 2, waking microcontroller unit 2 from deep sleep and entering the working state.

[0119] Specifically, the current consumption of microcontroller unit 2 in standby mode is no more than 500nA; when woken up, microcontroller unit 2 enters active mode and begins to execute the pre-programmed infrared alarm program.

[0120] It should be noted that after the microcontroller unit 2 is woken up, the external interrupt trigger signal from the output of comparator 11 to the microcontroller unit 2 is shielded to prevent repeated triggering caused by the output jitter of comparator 11 due to water level fluctuations during subsequent infrared signal transmission.

[0121] When current is applied to the base of transistor 31, the collector and emitter of transistor 31 form a closed loop to ground; the loop where light-emitting diode 34 is located is closed, the power supply supplies power to light-emitting diode 34 and ensures that light-emitting diode 34 continues to emit light.

[0122] It should be noted that after the microcontroller unit 2 completes the initialization operation, it supplies current to the base of the transistor 31; specifically, the output pin of the microcontroller unit 2 provides drive current to the base of the transistor 31 through the base resistor 32.

[0123] The base resistor 32 is connected in series between the output pin of the microcontroller unit 2 and the base of the transistor 31 to limit the magnitude of the base current. In this embodiment, the resistance value of the base resistor 32 is calculated to ensure that the base current is sufficient to drive the transistor 31 into a saturated conduction state, while not exceeding the maximum driving capability of the output pin of the microcontroller unit 2.

[0124] Transistor 31 is preferably an NPN bipolar junction transistor; when no current flows through the base of transistor 31 (i.e., under normal conditions), the bias voltage between the base and the emitter is zero, transistor 31 is in the cut-off state, the collector and the emitter present a high resistance state, the circuit of infrared LED 34 is in the open state, and infrared LED 34 is turned off.

[0125] When the microcontroller unit 2 supplies current to the base of transistor 31, the base current forms a forward bias between the base and the emitter, and transistor 31 enters the saturation conduction state. The voltage drop between the collector and the emitter drops to the saturation voltage drop (usually less than 0.3V), and the collector and the emitter are equivalent to a closed low-resistance path.

[0126] At this time, the circuit where the infrared LED 34 is located is closed; the circuit path is: power supply VCC → current limiting resistor 33 → infrared LED 34 → collector of transistor 31 → emitter of transistor 31 → system ground; the power supply supplies power to the infrared LED 34, and the infrared LED 34 continues to light up and emit infrared light.

[0127] It should be noted that the microcontroller unit 2 does not simply drive the output pin with a continuous high level. Instead, it precisely controls the high and low level switching timing of the output pin using a timer according to the encoding rules of the NEC protocol (an infrared remote control encoding standard that uses a 38kHz carrier wave, distinguishes logic 0 and 1 by pulse distance, and has a one's complement check and repetition code mechanism). Specifically: Microcontroller unit 2 starts a timer and generates a 38kHz PWM carrier signal at the output. This 38kHz carrier signal acts on the base of transistor 31, causing transistor 31 to switch on and off states rapidly at a frequency of 38kHz. Infrared LED 34 flashes at a frequency of 38kHz, generating a 38kHz modulated infrared carrier.

[0128] Meanwhile, the microcontroller unit 2 precisely controls the "transmit" and "off" time periods of the 38kHz carrier according to the timing specified by the NEC protocol through software delay or another timer, forming coded "pulses" (with carrier) and "gap" (without carrier); the duration of each "pulse" and "gap" corresponds to the encoding length of each bit of the preamble, user code (address code) and data code in the NEC protocol.

[0129] After the complete NEC data frame is sent, the microcontroller unit 2 keeps the output pin at a low level, the transistor 31 returns to the cutoff state, the infrared LED 34 turns off, and waits for about 100ms before starting to send the next frame; the entire data frame is repeated 3 to 5 times to improve the reception success rate of the infrared camera.

[0130] Infrared cameras deployed in the factory area capture light source signals, and the specific location of pipeline leaks is determined based on fixed infrared coding information.

[0131] The infrared light source signal emitted by the leakage detection device is captured by an infrared camera installed in the valve hall.

[0132] Specifically, the infrared receiving optical system at the front end of the infrared camera has bandpass filtering characteristics for 38kHz modulated infrared signals, which can effectively suppress the interference of ambient background thermal radiation (continuous spectrum) and only receive and respond to 38kHz modulated infrared light signals; when the infrared light-emitting diode 34 of the water leakage detection device emits a 38kHz modulated infrared signal, a flashing infrared light spot will appear at the corresponding position in the image of the infrared camera.

[0133] The infrared camera demodulates and decodes the captured infrared signals to extract the 16-bit user code and 8-bit data code from the NEC protocol data frame.

[0134] Based on the extracted fixed address code information, the specific pipeline leak location can be determined by querying the pre-stored device location information table. The device location information table records the correspondence between each device's user code, valve tower floor number, water pipe interface number, and physical coordinates. For example: User code 0x0001 → The first PVDF water pipe fitting interface on the east side of the first layer of the valve tower; User code 0x0002 → The second PVDF water pipe fitting interface on the east side of the first layer of the valve tower; User code 0x0003 → The hot-melt joint of the first PVDF water pipe on the west side of the first layer of the valve tower; When the monitoring terminal receives a water leakage alarm signal from a device with user code 0x0001, it can confirm that the water leakage point is located at the compression fitting of the first PVDF water pipe on the east side of the first layer of the valve tower. Maintenance personnel can go directly to this location for repair based on this information without having to check each layer and each pipe individually.

[0135] Importantly, the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A water leakage detection circuit, characterized in that: include, Signal detection circuit (1) is used to detect water pipe leakage; The microcontroller unit (2) is electrically connected to the signal detection circuit (1); The infrared emission driving circuit (3) is electrically connected to the microcontroller unit (2); The microcontroller unit (2) controls the infrared emission drive circuit (3) to emit an infrared alarm signal containing a fixed address code according to the output signal of the signal detection circuit (1).

2. The leakage detection circuit as described in claim 1, characterized in that: The signal detection circuit (1) includes a comparator (11), a pull-up resistor (12) electrically connected to the non-inverting input terminal of the comparator (11), and a voltage divider resistor (13) connected to the inverting input terminal of the comparator (11). The voltage divider resistor (13) provides a fixed threshold voltage for the signal detection circuit (1).

3. The leakage detection circuit as described in claim 2, characterized in that: A first probe (14) is connected between the non-inverting input terminal of the comparator (11) and the pull-up resistor (12). A second probe (15) is connected between the voltage divider resistor (13) and the ground. The first probe (14) and the second probe (15) are spaced apart.

4. A water leakage detection circuit as described in claim 3, characterized in that: The output of the comparator (11) is directly connected to the input pin of the microcontroller unit (2); The microcontroller unit (2) is configured as follows: When the output of the comparator (11) is high, the microcontroller unit (2) is in standby mode; When the output of the comparator (11) is low, the microcontroller unit (2) is in a woke-up working state.

5. A leakage detection circuit as described in claim 3 or 4, characterized in that: The output pin of the microcontroller unit (2) is connected to the infrared emission driving circuit (3); The infrared emission driving circuit (3) includes a transistor (31), a base resistor (32) connected to the base of the transistor (31), a current-limiting resistor (33) connected in series with the collector of the transistor (31), and a light-emitting diode (34). The emitter of the transistor (31) is grounded.

6. A leakage detection circuit as described in claim 5, characterized in that: The transistor (31) is configured such that when no current flows through the base of the transistor (31), the collector is disconnected from the emitter, and the light-emitting diode (34) is turned off. When current flows through the base of the transistor (31), the collector and emitter are closed, and the light-emitting diode (34) is activated.

7. A leakage detection circuit as described in claim 6, characterized in that: The reset pin of the microcontroller unit (2) is indirectly connected to the power supply.

8. A leakage detection circuit as described in claim 7, characterized in that: The microcontroller unit (2) is connected in series between the power supply and ground via two pins.

9. A leakage detection device, characterized in that: Including a leakage detection circuit as described in any one of claims 3 to 8; and, The clamp (4) is snapped onto the outside of the pipe connection, and a water collection trough (41) is formed at the bottom of the clamp (4). The water collection tank (41) has a recess inside that accommodates the first probe (14) and the second probe (15); When the recess is filled with water, a passage is formed between the first probe (14) and the second probe (15).

10. A method for detecting water leakage, characterized in that: Including a leakage detection circuit as described in any one of claims 5 to 8, and: When a leak occurs at the water pipe joint, the first probe (14) and the second probe (15) form a passage through the water. At this time, the voltage at the non-inverting input terminal of the comparator (11) is less than the threshold voltage at the inverting input terminal, and the comparator (11) outputs a low-level signal; The microcontroller unit (2) is activated upon receiving a low-level signal and supplies current to the base of the transistor (31); When current is applied to the base of transistor (31), the collector and emitter of transistor (31) form a closed loop to ground. The circuit containing the light-emitting diode (34) is closed, and the power supply supplies power to the light-emitting diode (34) and ensures that the light-emitting diode (34) continues to emit light; Infrared cameras deployed in the factory area capture light source signals, and the specific location of pipeline leaks is determined based on fixed infrared coding information.

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