Hand washing sink and leakage protector

Abstract

The utility model provides a hand washing sink and a leakage protector in order to solve the problems that a traditional leakage protector is low in sensitivity and weak leakage current is difficult to accurately detect in the prior art. The utility model belongs to the technical field of electrical safety protection equipment. The leakage protector comprises the following components: a controller, a digital-to-analog converter (DAC), a current-limiting resistor R1, a comparator COMP, a filter circuit, an indicating lamp LED and a PCB card. A current-limiting resistor R1, a digital-to-analog converter DAC and a controller of the leakage protector are matched with a comparator COMP, so that the tiny leakage current change can be quickly captured; a digital-to-analog converter DAC is combined with a filter circuit to ensure that reference voltage is stable and accurate, and the powerful performance of an STM32 chip guarantees stable operation of the system; the wide compatibility shows that the expansion interface of the PCB board card can be adapted to different hand washing sink devices; simple user interaction is achieved through an indicator light and a display screen, and use and maintenance are convenient.

Description

Technical Field

[0001] This utility model belongs to the technical field of electrical safety protection equipment, and in particular relates to a handwashing sink and a leakage current protection device. Background Technology

[0002] Handwashing basins are common facilities in daily life and industrial production. However, due to their structure and usage environment, they pose a certain risk of electric shock. For example, the insulation of the wiring inside the basin may be damaged due to long-term use, aging, moisture, or external force, allowing current to leak into normally non-energized objects such as the metal casing of the faucet, metal water pipes, and the metal parts of the basin. If a person comes into contact with these energized objects, an electric shock may occur, posing a serious threat to personal safety.

[0003] Traditional residual current devices (RCDs) have low sensitivity and cannot accurately detect weak leakage currents. They often only trigger protection when the leakage current is large. This means that users may not be able to detect the potential danger in the early stages of leakage, thus increasing the possibility of electric shock accidents. Utility Model Content

[0004] This invention addresses the problem that traditional leakage current protectors in the prior art have low sensitivity and are difficult to accurately detect weak leakage currents by providing a handwashing basin and a leakage current protector.

[0005] The technical solution adopted in this utility model is:

[0006] A residual current device (RCD) includes:

[0007] Controller;

[0008] A digital-to-analog converter (DAC); the input terminal of the DAC is connected to the controller, and it is used to convert the controller's digital signal into an analog signal and output it.

[0009] Multiple current-limiting resistors R1 are provided, with one end of each current-limiting resistor R1 connected to an object in the sink that is normally not electrified. The objects that are normally not electrified include the metal casing of the faucet, the metal water pipe, and the metal part of the sink.

[0010] Comparator COMP; the non-inverting input of comparator COMP is connected to the other end of the current-limiting resistor R1; the non-inverting input of comparator COMP is used to capture the current leaking from the sink device into the metal casing of the faucet, the metal water pipe, or the metal part of the sink; the inverting input of comparator COMP is connected to the output of the digital-to-analog converter (DAC); comparator COMP determines whether the metal casing of the faucet, the metal water pipe, or the metal part of the sink is leaking current by comparing the voltages at the non-inverting and inverting inputs; the output of comparator COMP is connected to the controller, and when the voltage at the non-inverting input of comparator COMP is higher than the voltage at the inverting input, the output of comparator COMP is high; when the voltage at the non-inverting input of comparator COMP is lower than the voltage at the inverting input, the output of comparator COMP is low.

[0011] An indicator LED is connected to the controller; once the controller receives a high level output from the comparator COMP output terminal, the indicator LED remains constantly lit.

[0012] Furthermore, a filter circuit is provided at the output terminal of the digital-to-analog converter (DAC) and the inverting input terminal of the comparator (COMP);

[0013] The input terminal of the filter circuit is connected to the output terminal of the digital-to-analog converter (DAC); the output terminal of the filter circuit is connected to the inverting input terminal of the comparator (COMP).

[0014] Furthermore, the filtering circuit includes:

[0015] Capacitor C1; one end of capacitor C1 is the input terminal of the filter circuit, and the other end of capacitor C1 is grounded;

[0016] Resistor R2; one end of resistor R2 is the input terminal of the filter circuit;

[0017] Capacitor C2; one end of capacitor C2 is connected to the other end of resistor R2, and the other end of capacitor C2 is grounded.

[0018] Furthermore, the controller is an STM32 chip.

[0019] Furthermore, it also includes:

[0020] The PCB board; the digital-to-analog converter (DAC), the current-limiting resistor R1, the controller, the filter circuit, and the comparator COMP are integrated on the PCB board.

[0021] Furthermore, the PCB board has an expansion interface. Different handwashing basins have different numbers of faucet metal shells, metal water pipes, and metal parts. The expansion interface can be used to add circuits corresponding to the faucet metal shells, metal water pipes, and metal parts of the handwashing basin, thereby making it compatible with different handwashing basins.

[0022] Furthermore, it also includes:

[0023] A display screen; the display screen is connected to the controller and is used to display the time when the leakage occurred.

[0024] Based on the same inventive concept, this utility model also provides a handwashing basin, including the aforementioned leakage current protection device.

[0025] The beneficial effects of this utility model are:

[0026] The leakage current protector disclosed in this utility model, with its current-limiting resistor R1, digital-to-analog converter (DAC), controller, and comparator COMP working together, can quickly capture minute changes in leakage current. The DAC, combined with the filter circuit, ensures a stable and accurate reference voltage. The powerful performance of the STM32 chip guarantees stable system operation and reduces the risk of false alarms and missed alarms. Its wide compatibility is demonstrated by the PCB board expansion interface, which can be adapted to different handwashing basin devices, making it highly versatile. The user-friendly interface is achieved through indicator lights and a display screen, facilitating use and maintenance. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Appendix Figure 1 This is a schematic diagram of a residual current device (RCD). Detailed Implementation

[0029] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0030] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the scope of this invention.

[0031] The embodiments of the utility model will now be described in detail with reference to the accompanying drawings.

[0032] Appendix Figure 1 This is a schematic diagram of a residual current device (RCD).

[0033] The leakage current protector disclosed in this embodiment includes the following components: a controller, a digital-to-analog converter (DAC), a current-limiting resistor R1, a comparator COMP, a filter circuit, indicator lights (LEDs), and a PCB board. The connection relationships between these components are described below:

[0034] Controller;

[0035] Digital-to-analog converter (DAC); The input of the DAC is connected to the controller to convert the controller's digital signals into analog signals and output them.

[0036] Multiple current-limiting resistors R1 are provided. One end of each current-limiting resistor R1 is connected to an object in the sink that is not normally electrified. Objects that are not normally electrified include the metal casing of the faucet, the metal water pipe, and the metal part of the sink.

[0037] Comparator COMP; the non-inverting input of comparator COMP is connected to the other end of the current-limiting resistor R1; the non-inverting input of comparator COMP is used to capture the current leaking into the metal casing of the faucet, metal pipe, or metal part of the sink in the handwashing basin equipment; the inverting input of comparator COMP is connected to the output of the digital-to-analog converter (DAC); comparator COMP determines whether there is leakage in the metal casing of the faucet, metal pipe, or metal part of the sink by comparing the voltage at the non-inverting input and the inverting input; the output of comparator COMP is connected to the controller. When the voltage at the non-inverting input of comparator COMP is higher than the voltage at the inverting input, the output of comparator COMP is high; when the voltage at the non-inverting input of comparator COMP is lower than the voltage at the inverting input, the output of comparator COMP is low.

[0038] The indicator LED is connected to the controller; once the controller receives a high level output from the comparator COMP terminal, the indicator LED remains constantly lit.

[0039] The functions and selection of each component are described in detail below:

[0040] Controller: An STM32 chip is selected. As the "brain" of the entire leakage current circuit breaker, the STM32 chip possesses powerful computing capabilities and rich peripheral interfaces. It is responsible for receiving signals from the comparator, controlling the status of indicator lights and the display screen, and handling various logic operations and data storage tasks. The STM32 chip is soldered onto a carefully designed PCB board, ensuring its pins are correctly connected to other components on the board to achieve smooth signal transmission and interaction.

[0041] Digital-to-Analog Converter (DAC): Its input terminals are closely connected to the corresponding pins of the STM32 chip. The function of the DAC is to accurately convert the digital signal output by the STM32 chip into an analog signal. During installation, special attention should be paid to the connection of the DAC chip's power supply pins and ground pins to ensure stable power supply and good grounding, in order to avoid conversion errors caused by power fluctuations or poor grounding.

[0042] Current-limiting resistor R1: Select a metal film resistor with an accuracy class of 0.1% and an appropriate rated power. One end of each current-limiting resistor R1 is connected via a high-quality wire to an object that is normally not energized, such as the metal casing of a sink faucet, a metal water pipe, or the metal part of the sink. During connection, ensure that the contact points between the wire and these objects are clean and secure to reduce contact resistance and ensure that leakage current can accurately pass through the current-limiting resistor R1. The other end of the current-limiting resistor R1 is connected to the non-inverting input of the comparator COMP. For ease of installation and management, these current-limiting resistors can be neatly arranged on a PCB board and connected to other components through reasonable wiring.

[0043] Comparator COMP: The comparator COMP is one of the key components in leakage current detection, enabling rapid and accurate comparison of two input voltages. This embodiment uses the MAX961 comparator, which features high speed and high accuracy, with a typical delay time of 4.5ns, allowing for rapid detection of voltage changes and performing excellently in leakage current detection circuits where response speed is extremely critical. The non-inverting input of the comparator COMP is connected to the other end of the current-limiting resistor R1 to capture minute voltage changes caused by current leakage into objects such as the metal casing of the faucet, metal water pipes, and metal parts of the sink. The inverting input of the comparator COMP is connected to the output of the digital-to-analog converter (DAC) to receive the reference voltage after digital-to-analog conversion and filtering. The output of the comparator COMP is connected to a specific pin of the STM32 chip, providing real-time feedback of the comparison result to the controller. When installing the comparator COMP, pay attention to the supply voltage and polarity of its power pins, as well as the protection of the input pins, to avoid damage to the chip from overvoltage or electrostatic discharge.

[0044] Filtering Circuit (Capacitor C1, Resistor R2, Capacitor C2): The filtering circuit consists of capacitor C1, resistor R2, and capacitor C2. It is used to filter out high-frequency noise and interference in the output signal of the digital-to-analog converter (DAC), improving the stability and accuracy of the reference voltage. One end of capacitor C1 serves as the input terminal of the filtering circuit, connected to the output terminal of the DAC, while the other end is grounded. One end of resistor R2 is also connected to the output terminal of the DAC, while the other end is connected to one end of capacitor C2, and the other end of capacitor C2 is grounded. When selecting capacitors and resistors, appropriate capacitance and resistance values ​​should be chosen based on the circuit's operating frequency and noise characteristics to achieve the best filtering effect. When mounting the components of the filtering circuit on the PCB board, attention should be paid to the component layout and wiring to minimize the influence of parasitic capacitance and inductance, ensuring that the performance of the filtering circuit is not interfered with.

[0045] Indicator LED: High-brightness, low-power LEDs are selected as the leakage current indication element. The positive terminal of the LED is connected to the output pin of the STM32 chip through a current-limiting resistor (the appropriate resistance value is selected according to the LED's operating current and the output drive capability of the STM32 chip), and the negative terminal of the LED is grounded. When the STM32 chip receives a high-level signal from the comparator COMP (indicating leakage current detection), the output pin outputs a high level, and current flows through the current-limiting resistor to the LED, causing it to light up, thus visually indicating to the user that there is a leakage current in the sink. The LED is installed in a conspicuous location near the sink, such as on the wall above the sink or on the edge of the countertop, for easy observation by the user.

[0046] Display Screen: An OLED display screen is selected and connected to the STM32 chip via communication interfaces such as I2C or SPI. The display screen is used to show information such as the time of leakage occurrence, providing users with a detailed record of leakage conditions. When installing the display screen, ensure that the communication line between it and the STM32 chip is correctly connected and that the power supply voltage to the display screen is stable.

[0047] PCB Board: The PCB board is the carrier of the entire residual current device (RCD), integrating all the aforementioned components onto a well-designed PCB board. During the PCB board design process, factors such as component layout, wiring, power distribution, and grounding must be fully considered to ensure circuit performance and reliability. For example, digital and analog circuits are laid out separately to avoid interference between digital and analog signals; the routing of power and ground lines is planned rationally to reduce power supply noise and ground loops; multiple grounding vias are set on the PCB board to improve grounding reliability. The PCB board also has expansion interfaces. Different sinks have different numbers of faucet metal shells, metal pipes, and sink metal parts. Expansion interfaces allow for the addition of circuits corresponding to these components, ensuring compatibility with different sinks.

[0048] This embodiment also includes a handwashing basin device:

[0049] Handwashing basin fixtures include components such as faucets, metal water pipes, and the metal parts of the basin. The faucet is made of metal, and its casing is connected to the metal water pipes, forming a conductive whole. Before installing a residual current device (RCD), a comprehensive inspection of the handwashing basin fixtures must be conducted to ensure that the connections between the faucet, metal water pipes, and the metal parts of the basin are secure, without loosening or corrosion, and that these components are not energized under normal conditions.

[0050] The working process of the residual current device disclosed in this embodiment is as follows:

[0051] System initialization

[0052] When the leakage current protector is powered on, the STM32 chip first performs system initialization, including clock configuration, GPIO pin initialization, communication interface initialization such as I2C or SPI, and timer initialization. During initialization, the STM32 chip sets the output of the digital-to-analog converter (DAC) to an initial value (a low voltage value), sets the indicator LEDs to the off state, and the display screen is also either off or displaying the initial interface.

[0053] Simultaneously, the STM32 chip configures the output pins of the comparator COMP to ensure it can correctly read the comparator's output signal. Furthermore, the STM32 chip initializes its internal memory modules, preparing them for storing data such as leakage current information.

[0054] Normal operating condition (no leakage).

[0055] When the handwashing basin equipment is working normally and there is no leakage current, no leakage current flows through the metal casing of the faucet, the metal water pipe, the metal part of the basin, etc., or the leakage current is very small, so that the voltage drop generated across the current limiting resistor R1 can be ignored.

[0056] At this time, the voltage at the non-inverting input of comparator COMP (determined by the voltage across current-limiting resistor R1) is lower than the voltage at the inverting input (the reference voltage output by the digital-to-analog converter DAC and filtered by the circuit). The comparator COMP outputs a low-level signal. Upon receiving this low-level signal, the STM32 chip determines that there is no leakage.

[0057] The STM32 chip keeps the indicator LEDs off and does not send commands to the display screen to show information such as leakage time. The display screen continues to show the initial interface or remains off. The STM32 chip reads the output signal of the comparator COMP at regular intervals to monitor leakage in real time, but does not perform any additional operations when there is no leakage. The entire system is in a low-power normal monitoring state.

[0058] Leakage detection and alarm

[0059] When a handwashing basin experiences a leakage current due to some reason (such as aging wires, damaged insulation, or water ingress), the leakage current will flow to the ground through the metal casing of the faucet, the metal water pipe, and the metal parts of the basin. When the leakage current flows through the current-limiting resistor R1, it will generate a voltage drop across the resistor, causing the voltage at the non-inverting input of the comparator COMP to rise.

[0060] When the voltage at the non-inverting input is higher than the voltage at the inverting input (i.e., the reference voltage output by the digital-to-analog converter DAC), the state of the comparator COMP output flips, outputting a high-level signal. The STM32 chip detects this high-level signal from the comparator COMP in real time and immediately enters the leakage current handling routine.

[0061] In the leakage current handling procedure, the STM32 chip first controls the indicator LED to light up by outputting a high level through the GPIO pin. The current passes through the current-limiting resistor to drive the LED to light up, indicating to the user that there is a leakage in the sink and reminding the user to pay attention to safety and avoid the risk of electric shock.

[0062] Simultaneously, the STM32 chip reads the current system time and sends the time information of the leakage occurrence to the display screen via the I2C communication interface. After receiving the time information, the display screen shows the specific time of the leakage occurrence, allowing users to understand the exact moment of the leakage and providing accurate timing information for subsequent troubleshooting and repair.

[0063] Furthermore, the STM32 chip can store information such as the time of leakage in its internal storage module, allowing users to export the stored data via a specific interface for further analysis and statistics when needed. During the leakage period, the STM32 chip will keep the indicator LED lit and the display showing the leakage time until the leakage disappears.

[0064] Recovery after leakage disappears

[0065] When the leakage fault of the handwashing basin equipment is repaired and the leakage current disappears, the voltage drop across the current limiting resistor R1 also disappears. The voltage at the non-inverting input of comparator COMP is once again lower than the voltage at the inverting input, and the output of comparator COMP outputs a low-level signal.

[0066] After detecting a low-level signal from the comparator COMP, the STM32 chip determines that the leakage has disappeared and enters the recovery program. In the recovery program, the STM32 chip first turns off the indicator LEDs and stops sending commands to the display to show the leakage time. The display can then return to its initial state or be turned off.

[0067] The residual current device disclosed in this embodiment has the following advantages:

[0068] Precise Leakage Detection: Utilizing a high-precision current-limiting resistor R1 and a sensitive comparator COMP, the system can quickly and accurately detect minute changes in leakage current within the handwashing station. This allows for timely detection of potential leakage hazards, effectively preventing electric shock accidents and significantly enhancing user safety during handwashing station use. For example, even extremely weak leakage currents, once they reach a set threshold, will trigger an alarm mechanism, informing the user of the potential danger immediately and enabling them to take appropriate action.

[0069] Real-time alerts: When a leakage is detected, the indicator LED immediately remains constantly lit. This intuitive visual warning quickly attracts the user's attention, ensuring the leakage warning signal is clearly visible regardless of the environment or lighting conditions. Simultaneously, the display shows the real-time time of the leakage, providing users with specific leakage information. This helps users accurately determine the moment the leakage occurred, facilitating subsequent troubleshooting and repair, and further enhancing safety and traceability.

[0070] Stable circuit design: The combination of the digital-to-analog converter (DAC) and the filtering circuit ensures the stability and accuracy of the reference voltage. The filtering circuit effectively removes noise and interference generated during the digital-to-analog conversion process, making the reference voltage received by the comparator COMP purer, thereby improving the reliability and accuracy of leakage current detection.

[0071] The controller uses an STM32 chip, whose powerful processing capabilities and stable performance enable it to efficiently process various signals and data, ensuring the stable operation of the entire leakage current protection system. The STM32 chip also features abundant peripheral interfaces and reliable internal resources, meeting the needs of the leakage current protector in different operating scenarios.

[0072] Wide compatibility: The PCB board is also equipped with an expansion interface. Different handwashing sinks have different numbers of faucet metal shells, metal water pipes, and handwashing basin metal parts. Through the expansion interface, the corresponding circuits of faucet metal shells, metal water pipes, and handwashing basin metal parts can be added, thus making it compatible with different handwashing sinks.

[0073] Simple user interaction: The design of the LED indicator lights and display screen provides users with a simple and clear interaction method. Users do not need professional electrical knowledge; they can easily understand the leakage status and relevant time information of the handwashing basin equipment by simply observing the status of the indicator lights and the information displayed on the screen, facilitating daily use and maintenance.

Claims

1. A residual current device (RCD), characterized in that, include: Controller; Digital-to-analog converter (DAC); The digital-to-analog converter (DAC) input is connected to the controller and is used to convert the controller's digital signal into an analog signal and output it. Multiple current-limiting resistors R1 are provided, with one end of each current-limiting resistor R1 connected to an object in the sink that is normally not electrified. The objects that are normally not electrified include the metal casing of the faucet, the metal water pipe, and the metal part of the sink. Comparator COMP; the non-inverting input of comparator COMP is connected to the other end of the current-limiting resistor R1; the non-inverting input of comparator COMP is used to capture the current leaking from the sink device into the metal casing of the faucet, the metal water pipe, or the metal part of the sink; the inverting input of comparator COMP is connected to the output of the digital-to-analog converter (DAC); comparator COMP determines whether the metal casing of the faucet, the metal water pipe, or the metal part of the sink is leaking current by comparing the voltages at the non-inverting and inverting inputs; the output of comparator COMP is connected to the controller, and when the voltage at the non-inverting input of comparator COMP is higher than the voltage at the inverting input, the output of comparator COMP is high; when the voltage at the non-inverting input of comparator COMP is lower than the voltage at the inverting input, the output of comparator COMP is low. An indicator LED is connected to the controller; once the controller receives a high level output from the comparator COMP output terminal, the indicator LED remains constantly lit.

2. The residual current device according to claim 1, characterized in that, There is a filter circuit at the output of the digital-to-analog converter (DAC) and the inverting input of the comparator (COMP). The input terminal of the filter circuit is connected to the output terminal of the digital-to-analog converter (DAC); the output terminal of the filter circuit is connected to the inverting input terminal of the comparator (COMP).

3. The residual current device according to claim 2, characterized in that, The filtering circuit includes: Capacitor C1; one end of capacitor C1 is the input terminal of the filter circuit, and the other end of capacitor C1 is grounded; Resistor R2; one end of resistor R2 is the input terminal of the filter circuit; Capacitor C2; one end of capacitor C2 is connected to the other end of resistor R2, and the other end of capacitor C2 is grounded.

4. The residual current device according to claim 1, characterized in that, The controller is an STM32 chip.

5. The residual current device according to claim 2, characterized in that, Also includes: PCB board; The digital-to-analog converter (DAC), the current-limiting resistor R1, the controller, the filter circuit, and the comparator COMP are integrated on the PCB board.

6. The residual current device according to claim 5, characterized in that, The PCB board has an expansion interface. Different handwashing basins have different numbers of faucet metal shells, metal water pipes, and metal parts. The expansion interface can be used to add circuits corresponding to the faucet metal shells, metal water pipes, and metal parts of the handwashing basin, thus making it compatible with different handwashing basins.

7. The residual current device according to any one of claims 1-6, characterized in that, Also includes: A display screen; the display screen is connected to the controller and is used to display the time when the leakage occurred.

8. A handwashing basin, characterized in that, Includes the residual current device as described in any one of claims 1-7.

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