A gas stove solenoid valve auxiliary shut-off system

Abstract

This invention discloses an auxiliary shut-off system for a gas stove's solenoid valve, relating to the field of gas stove safety protection technology. The system includes a wall-mounted main control unit, an ultra-thin single-coil magnetic clip, a dual-redundant power supply, and a Bluetooth communication unit. The magnetic clip holds the flameout wire in place, achieving installation without wire breakage or modification. A single coil simultaneously performs ignition detection, magnetic field polarity determination, and reverse excitation to shut off gas, eliminating the need for Hall effect sensors and sampling resistors. The H-bridge outputs a 10–16mA reverse current to cancel the solenoid valve's magnetic force, and a D trigger achieves a hardware-locked gas shut-off state. Seamless switching between dual power supplies is achieved, with standby power consumption ≤6mW and an operating temperature range of -40℃ to 125℃. This invention is easy to install, features a secure self-locking mechanism, low power consumption and stability, and does not interfere with the original factory protection logic, making it suitable for intelligent safety protection of household gas stoves.

Description

Technical Field

[0001] This invention belongs to the field of safety protection and intelligent security power and gas cut-off control technology for household gas stoves, specifically involving an external auxiliary safety system that achieves passive shut-off of the solenoid valve through single-coil magnetic field detection and reverse magnetic field cancellation. Background Technology

[0002] Existing gas stove safety shut-off devices generally employ wire-cutting modifications, Hall effect sensor detection, or series sampling resistors for control. These methods suffer from problems such as improper installation, high temperature drift, excessive size, high failure rate, lack of hardware safety locking, and inability to install in the confined space under the stove. Furthermore, they easily interfere with the original manufacturer's flameout protection logic, making it difficult to meet the safety, stability, and compliance requirements for household gas safety. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a gas stove solenoid valve auxiliary shut-off system that achieves non-wire breaking, no modification required, passive detection, hardware self-locking, low power consumption and stable operation, without affecting the original factory safety logic, thus solving the industry pain points of traditional modifications being illegal, unreliable, and limited in installation. Technical solution

[0004] A gas stove solenoid valve auxiliary shut-off system includes a separate wall-mounted main control circuit unit, an ultra-thin single-coil magnetic clip induction unit, a dual redundant power supply unit, and a wireless communication unit. The wall-mounted main control circuit unit is installed in the normal temperature and dry area of ​​the cabinet, and the ultra-thin single-coil magnetic clip induction unit is independently clipped onto the single wire of the gas stove flameout protection without altering the original wiring.

[0005] The ultra-thin single-coil magnetic clip induction unit adopts a flat, open-close nanocrystalline magnetic core structure with an overall outer diameter ≤15mm, a closed thickness ≤5mm, and a fixed air gap of 0.15mm. The magnetic core is wound with a single functional coil, which is made of 0.06mm enameled wire with 150 turns and a DC internal resistance of 13–15Ω. The single functional coil simultaneously realizes three functions: dynamic ignition signal detection, steady-state DC magnetic field polarity determination, and reverse excitation air cut-off execution.

[0006] The system requires no Hall effect sensor or current sampling resistor. It identifies the polarity of the steady-state DC magnetic field through a hysteresis comparator, passively determining the presence and direction of DC current in the flameout circuit. The wall-mounted main control circuit unit includes an STM8L low-power main controller, a hysteresis comparator discrimination circuit, an H-bridge bidirectional constant current drive circuit, and a hardware self-locking circuit. The hardware self-locking circuit is composed of D flip-flops. After the gas is cut off, the hardware forcibly latches the off state, and it cannot be automatically reset in the event of power failure, program abnormality, or communication interruption.

[0007] The H-bridge bidirectional drive circuit outputs a constant excitation current in the corresponding direction according to the magnetic field polarity, with an excitation current range of 10–16mA. This excitation current is used to offset the magnetic force pulling the gas stove's solenoid valve, achieving passive gas shut-off. The dual redundant power supply unit includes a 5V Type-C main power supply circuit and a 3.0V lithium battery backup boost circuit. The two power supplies automatically and seamlessly switch, and the power supply does not drop or release the hardware safety latch during the power outage switching process.

[0008] The unit's static standby power consumption is ≤6mW, operating power consumption is ≤24mW, and the operating temperature range is -40℃ to 125℃, making it suitable for high-temperature and high-humidity environments in kitchens and bathrooms. The system is an external auxiliary safety device, with a lower operating priority than the original flameout protection device on the stove, and does not interfere with any of the original safety logic. Beneficial effects

[0009] This invention adopts an external snap-on installation, which does not require wire breaking or machine modification and is compliant and safe; the single coil is triple-reused, eliminating the need for Hall elements and sampling resistors, resulting in a minimalist structure, ultra-thin size, and strong anti-interference capability; hardware self-locking ensures that it cannot self-reset after gas interruption, providing a high level of safety; seamless switching between dual power supplies, low power consumption and wide temperature design, adaptable to harsh kitchen and bathroom environments, does not affect the original flameout protection logic, and significantly improves overall stability, safety, and practicality. Detailed Implementation

[0010] The present invention will be further described in detail below with reference to specific embodiments.

[0011] This embodiment represents the optimal hardware implementation method that can be directly mass-produced and is compatible with all brands of household gas stoves. The system is divided into four main parts: an ultra-thin, openable single-coil magnetic clamp induction unit, a 3.3V low-power main control unit, a dual-path automatic switching power supply unit, and a Bluetooth wireless communication and hardware self-locking execution unit.

[0012] The magnetic core is made of nanocrystalline high-permeability alloy with a permeability of 80,000 @ 1kHz. The core structure is a flat, snap-fit ​​type with a maximum outer diameter of 15mm, a total closed thickness of 5mm, an inner diameter of 3mm, a fixed standard air gap of 0.15mm, and a stable coupling efficiency of 0.15–0.18. The coil uses 0.06mm high-temperature resistant polyurethane enameled wire, tightly wound 150 turns in one direction, without delamination or cross-winding. The finished product has a DC internal resistance of 13–15Ω at room temperature, an insulation withstand voltage of 500V AC, and a single-sided lead length of 10cm, suitable for narrow bottom wiring.

[0013] The single coil features bidirectional multiplexing: during the dynamic ignition phase, it captures the alternating magnetic field generated by current jumps to identify the stove's ignition action; during the steady-state combustion phase, it captures the polarity of a 150mA constant DC magnetic field, achieving DC direction discrimination without Hall effect or sampling resistor; during the gas cut-off execution phase, a 10–16mA reverse constant current is applied, generating a reverse magnetomotive force to cancel the original solenoid valve's magnetic field. The magnetomotive force balance satisfies: N2I2η = N1I1, 150×16mA×0.15=360 standard magnetomotive force, which can completely cancel the original solenoid valve's magnetic force.

[0014] The main control chip is an ultra-low power industrial-grade STM8L051F3U6, with a wide temperature range of -40℃ to 125℃. The peripheral fixed circuit modules include: an LMV331 hysteresis comparator circuit, which builds a 3.3V single-supply symmetrical bias circuit to filter ignition pulse interference and output standard logic levels; an H-bridge bidirectional constant current drive circuit composed of four SI2302 transistors, with hardware current limiting of 10–16mA, and a 1N4148WS ultra-fast recovery diode connected in parallel across the coil to absorb reverse electromotive force; a hardware fail-safe self-locking circuit using a 74HC74 D flip-flop, which latches after gas interruption and can only be reset by a dedicated instruction; and an EMC anti-interference circuit using a ferrite bead, a 3.3A TVS diode, and a single-point common ground design to meet the requirements of strong interference environments.

[0015] Dual redundancy power supply: The main power supply is a Type-C 5V input, with an XC6206 regulator outputting 3.3V; the backup power supply consists of two series-connected 3.0V lithium batteries, boosted and regulated to 3.3V by an SX1308. The switching logic prioritizes AC mains power when external power is ≥4.7V, and seamlessly switches to battery power when external power is <4.7V. The battery voltage is sampled in real time by the MCU ADC, and a low battery alarm is pushed via Bluetooth when the voltage drops below 2.75V. The static standby power consumption is ≤6mW, and the power consumption during gas cut-off operation is ≤24mW.

[0016] The wireless communication uses a high-temperature resistant industrial BLE module, filtered by a ferrite bead and capacitor, supporting remote gas shut-off, remote unlocking and reset, online device status reporting, and battery level reporting functions. The entire unit adopts a completely separate and isolated installation structure: the motherboard, Bluetooth, and power supply are fixed to the back panel of the cabinet; only the ultra-thin magnetic clip is fixed to the single flameout wire at the bottom of the stove, without breaking the wire, modifying the machine, or affecting any original factory protection logic.

[0017] Workflow: Upon power-up, the device enters passive magnetic field monitoring standby mode; when the user ignites the device, the circuit current changes abruptly, the coil induces a dynamic electromotive force, and the MCU identifies the ignition status; after combustion stabilizes, the circuit forms a constant DC magnetic field of 150mA, the comparator outputs a fixed polarity level, completing the current direction identification; upon receiving a Bluetooth gas cut-off command from the mobile phone, the MCU outputs the corresponding H-bridge commutation level; a reverse 10–16mA constant current is applied to the coil, the reverse magnetic field cancels the solenoid valve's magnetic force, and the valve core falls due to its own weight to cut off the gas supply; the D trigger hardware latches the gas cut-off status; the user issues an unlock command to release the latch, and the device resumes monitoring mode.

[0018] This embodiment completely solves six major industry pain points of traditional solutions: illegal modification, Hall temperature drift, excessive size, high temperature failure, lack of hardware safety lock, and inability to install in confined spaces.

Claims

1. A gas stove solenoid valve auxiliary shut-off system, characterized in that: It includes a separate wall-mounted main control circuit unit, an ultra-thin single-coil magnetic clip sensing unit, a dual redundant power supply unit, and a wireless communication unit; the wall-mounted main control circuit unit is installed in the normal temperature area of ​​the cabinet, and the ultra-thin single-coil magnetic clip sensing unit is independently clipped onto the single wire of the gas stove's flameout protection without altering the original wiring.

2. The system according to claim 1, characterized in that: The ultra-thin single-coil magnetic clip induction unit adopts a flat, open-close nanocrystalline magnetic core structure with an overall outer diameter ≤15mm, a closed thickness ≤5mm, and a fixed air gap of 0.15mm. The magnetic core is wound with a single functional coil, which is 150 turns of 0.06mm enameled wire with a DC internal resistance of 13–15Ω. The single functional coil simultaneously realizes three functions: dynamic ignition signal detection, steady-state DC magnetic field polarity determination, and reverse excitation air cut-off execution.

3. The system according to claim 2, characterized in that: The system requires no Hall sensor or current sampling resistor. It identifies the polarity of the steady-state DC magnetic field through a hysteresis comparator and passively determines the presence and direction of DC current in the shutdown circuit.

4. The system according to claim 1, characterized in that: The wall-mounted main control circuit unit includes an STM8L low-power main controller, a hysteresis comparator discrimination circuit, an H-bridge bidirectional constant current drive circuit, and a hardware self-locking circuit. The hardware self-locking circuit is composed of D flip-flops. After the gas supply is cut off, the hardware forces the latch to be in the off state. It cannot be automatically reset in the event of power failure, program abnormality, or communication interruption.

5. The system according to claim 4, characterized in that: The H-bridge bidirectional drive circuit outputs a constant excitation current in the corresponding direction according to the polarity of the magnetic field. The excitation current range is 10–16 mA. The passive gas cut-off is achieved by offsetting the magnetic force of the gas stove solenoid valve by the magnetomotive force.

6. The system according to claim 1, characterized in that: The dual redundant power supply unit includes a 5V Type-C main power supply circuit and a 3.0V lithium battery backup boost circuit; the two power supplies automatically and seamlessly switch, and the power is not lost or the hardware safety latch is not released during the power failure switching process.

7. The system according to claim 1, characterized in that: The unit has a static standby power consumption of ≤6mW, an operating power consumption of ≤24mW, and an operating temperature range of -40℃ to 125℃, making it suitable for high-temperature and high-humidity environments in kitchens and bathrooms.

8. The system according to claim 1, characterized in that: The system is an external auxiliary safety device, with a lower working priority than the original flameout protection device of the stove, and does not interfere with any of the original safety logic.