Circuit for closing electromagnetic valve in power failure

Abstract

The utility model belongs to the technical field of electromagnetic valve control, and particularly relates to a circuit for closing an electromagnetic valve in power failure, a voltage conversion module, a microcontroller, an electromagnetic valve driving circuit and the electromagnetic valve. The electromagnetic valve driving circuit is additionally provided with a fifth resistor R5, a sixth resistor R6 and a second triode polar tube V2 on the basis of an existing electromagnetic valve driving circuit; when the power supply is cut off, the first polar capacitor C1 is stored with energy before power failure, and the I / O port of the microcontroller does not output any level signal any more, so that the base electrode of the second triode V2 is pulled down by the sixth resistor R6 to be at a low level, the second triode V2 is cut off, the first triode V1 and the MOS tube are conducted under the action of the fifth resistor R5, and the first triode V1 and the MOS tube are switched off. The first polar capacitor C1 discharges electricity to the electromagnetic valve through the MOS tube, so that the electromagnetic valve is automatically closed, gas supply is automatically closed during power failure, and danger is avoided.

Description

Technical Field

[0001] This utility model belongs to the field of electromagnetic valve control technology, specifically relating to a circuit for shutting off an electromagnetic valve when power is cut off. Background Technology

[0002] In the field of gas alarms, the most important safety devices are gas alarms and emergency gas shut-off valves. Gas alarms are used to detect gas leaks in residential kitchens. When a gas leak is detected, an audible and visual alarm is triggered, and the emergency gas shut-off valve is activated to shut off the gas supply, preventing further gas leakage and potential dangerous accidents.

[0003] If the power is cut off due to a temporary power outage or to prevent electrical hazards, such as when a restaurant turns off the power to its kitchen at night or when a family is away for an extended period, the gas alarm will lose power and will no longer be able to monitor for gas leaks. However, the gas pipeline will still be in normal operation. If a gas leak occurs due to abnormal reasons during a power outage, it can easily lead to a dangerous situation.

[0004] Currently, almost all gas alarms are powered by mains electricity. The gas alarm and solenoid valve are connected either wired or wirelessly. When connected wired, the valve's drive circuit is located inside the gas alarm; when wireless, the drive circuit is located inside the valve itself. The solenoid valve is typically normally open, closed by a low-pressure DC pulse. When the solenoid valve is turned off, the gas supply is shut off to ensure gas safety in homes. (Specific details follow...) Figure 4 As shown, switch K1 uses a normally closed contact of a relay. Normally, the relay coil is energized, and the normally closed contact K1 is open, so the solenoid valve does not operate. When a gas leak occurs, the microprocessor controls the relay to activate, closing the K1 contact and shutting off the solenoid valve. When the alarm loses power, the relay coil loses the microprocessor's control, the K1 contact returns to its closed state, and the solenoid valve activates, thus achieving the function of closing the solenoid valve upon power failure. In this design, the relay's continuous energization is detrimental to its lifespan, potentially leading to contact malfunction, and the relay itself is relatively expensive.

[0005] Current solutions for achieving power-off shut-off of solenoid valves also include using software to implement this method. This approach requires acquiring mains power signals for timely detection of power outages. It also necessitates adding a large capacitor or a backup power supply to the microprocessor's power supply terminal to delay power delivery to the microprocessor after a mains power outage, ensuring the execution of the control command to close the solenoid valve. This solution requires occupying one of the microprocessor's I / O ports to monitor the mains power outage, which is difficult to implement and increases costs for microprocessors with limited I / O ports. Summary of the Invention

[0006] In order to solve the technical problems existing in the background art, the present invention provides a circuit for shutting off a solenoid valve when the power is cut off, which has a simple structure, low cost and is easy to implement.

[0007] To achieve the above technical solution, this utility model provides a circuit for shutting off a solenoid valve when power is off, including: a voltage conversion module, a microcontroller, a solenoid valve drive circuit, and a solenoid valve.

[0008] The microcontroller and solenoid valve drive circuit are connected to the mains power supply through a voltage conversion module to convert the mains voltage into the voltage required by the microcontroller and solenoid valve drive circuit.

[0009] The solenoid valve drive circuit includes: a first resistor R1 and a fifth resistor R5; the first ends of the first resistor R1 and the fifth resistor R5 are connected to the first output terminal of the voltage conversion module; the second end of the first resistor R1 is connected to the positive terminal of the first polarized capacitor C1, the first end of the second resistor R2, and the source of the MOSFET; the negative terminal of the first polarized capacitor C1 is grounded; the second end of the second resistor R2 is connected to the gate of the MOSFET and the first end of the third resistor R3; the second end of the third resistor R3 is connected to the collector of the first transistor V1; the base of the first transistor V1 is connected to the second end of the fifth resistor R5 and the collector of the second transistor V2; the emitter of the first transistor is grounded; the base of the second transistor V2 is connected to the first end of the fourth resistor R4; the second end of the fourth resistor R4 is connected to the I / O port of the microcontroller and the first end of the sixth resistor R6; the second end of the sixth resistor R6 and the emitter of the second transistor V2 are grounded; the drain of the MOSFET is connected to port C+ of connector JP1 for connection with the solenoid valve; port C- of connector JP1 is grounded.

[0010] Furthermore, the microcontroller is an STM32 series microcontroller.

[0011] Furthermore, the solenoid valve drive circuit includes: a first diode D1, and the first output terminal of the voltage conversion module is connected to the first terminal of the first resistor R1 and the first terminal of the fifth resistor R5 through the first diode D1.

[0012] The beneficial effects of this utility model are:

[0013] This utility model belongs to the field of household emergency shut-off control technology, specifically involving a circuit for closing a solenoid valve upon power failure, comprising a voltage conversion module, a microcontroller, a solenoid valve drive circuit, and a solenoid valve. The solenoid valve drive circuit, based on an existing solenoid valve drive circuit, adds a fifth resistor R5, a sixth resistor R6, and a second transistor V2. When the power is disconnected, the first polarized capacitor C1, which has already stored energy before the power failure, no longer outputs any level signal from the microcontroller's I / O port. This causes the base of the second transistor V2 to be pulled low by the sixth resistor R6, thus turning off the second transistor V2. The first transistor V1 and the MOSFET conduct under the action of the fifth resistor R5. The first polarized capacitor C1 discharges through the MOSFET to the solenoid valve, causing the solenoid valve to automatically close. This achieves automatic shut-off of the gas supply upon power failure, preventing potential danger.

[0014] (2) The circuit is low in cost, only adding two resistors, one transistor and one diode to the original circuit, all of which are SMT packaged and small in size. While ensuring the original circuit function, it realizes the function of shutting off the solenoid valve when the power is off.

[0015] (3) The circuit is simple and easy to implement, and can shut off the valve when the power is cut off without the need for additional manual operation, thus ensuring gas safety.

[0016] Advantages of the present invention in additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0018] Figure 1 This is an electrical principle block diagram of the circuit for the power-off shut-off solenoid valve of this utility model;

[0019] Figure 2 This is a circuit diagram of a solenoid valve drive circuit according to an embodiment of the present invention;

[0020] Figure 3 This is a circuit diagram of a solenoid valve drive circuit in the prior art.

[0021] Figure 4 This is a schematic diagram of the closing principle of an existing solenoid valve in the prior art. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, each technical and scientific term used in this embodiment has the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] In this utility model, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of the structural relationship between the various components or elements of this utility model and do not specifically refer to any component or element in this utility model. They should not be construed as limiting this utility model.

[0026] In this utility model, terms such as "fixed connection," "connected," and "joined" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. For researchers or maintenance personnel in this field, the specific meaning of the above terms in this utility model can be determined according to the specific circumstances, and should not be construed as a limitation of this utility model.

[0027] Example 1:

[0028] like Figure 1 and Figure 2 As shown, this embodiment provides a circuit for shutting off a solenoid valve when power is off, including: a voltage conversion module 2, a microcontroller 1, a solenoid valve drive circuit 4, and a solenoid valve 5.

[0029] Voltage conversion module 2 is connected to the mains power supply to obtain the mains voltage and convert the mains voltage into the voltage required by the microcontroller and solenoid valve drive circuit.

[0030] The voltage conversion module 2 is connected to the microcontroller 1 and the solenoid valve drive circuit 4 to provide them with the required voltage;

[0031] Microcontroller 1 is connected to solenoid valve 5 via solenoid valve drive circuit 4, so as to control the opening and closing of solenoid valve by sending signals to the solenoid valve drive circuit. The solenoid valve is a normally open solenoid valve of DN15 or DN20 type. Normally, no control signal is applied to this normally open solenoid valve, and the air path is open. When a pulse signal is applied, the solenoid valve actuates, closing the air path.

[0032] Existing solenoid valve drive circuits used to control the on / off state of solenoid valves (such as...) Figure 3 (As shown) The solenoid valve is controlled by a voltage converter that converts AC power to DC power. Specifically, when the alarm detects a gas leak, the microcontroller 1 sends a control signal, which, through the solenoid valve drive circuit, outputs a pulse signal to close the solenoid valve. If the power is disconnected due to a temporary power outage or to prevent electrical hazards, the voltage converter cannot obtain power, meaning the microcontroller loses its power supply and cannot output a control signal. Consequently, the microcontroller cannot control the solenoid valve, and therefore cannot disconnect the gas supply. This leaves the gas pipeline in a state of continuous gas flow, which can easily lead to a hazard.

[0033] The solenoid valve drive circuit 4 of this utility model is an improvement on the existing solenoid valve drive circuit used to control the on / off state of the solenoid valve, so as to realize the function of closing the solenoid valve when power is off. Specifically, as follows: Figure 2 As shown, the solenoid valve drive circuit 4 includes: a first diode D1, the anode of which is connected to the input terminal of the solenoid valve drive circuit for obtaining the required voltage, so as to obtain the required voltage through a voltage conversion module; the cathode of the first diode D1 is connected to the first terminal of the first resistor R1 and the first terminal of the fifth resistor R5; the second terminal of the first resistor R1 is connected to the anode of the first polarized capacitor C1, the first terminal of the second resistor R2, and the source of the MOSFET; the cathode of the first polarized capacitor C1 is grounded; the second terminal of the second resistor R2 is connected to the gate of the MOSFET and the first terminal of the third resistor R3. The second terminal of the third resistor R3 is connected to the collector of the first transistor V1; the base of the first transistor V1 is connected to the second terminal of the fifth resistor R5 and the collector of the second transistor V2; the emitter of the first transistor is grounded; the base of the second transistor V2 is connected to the first terminal of the fourth resistor R4; the second terminal of the fourth resistor R4 is connected to the I / O port of the microcontroller and the first terminal of the sixth resistor R6; the second terminal of the sixth resistor R6 and the emitter of the second transistor V2 are grounded; the drain of the MOSFET is connected to port C+ of connector JP1 for connection with the solenoid valve; port C- of connector JP1 is grounded.

[0034] It should be noted that the solenoid valve in this embodiment is a normally open solenoid valve that is closed by a low-voltage pulse power supply.

[0035] In this embodiment, all components in the solenoid valve drive circuit are packaged on the substrate using SMT packaging technology for easy installation and disassembly.

[0036] In this embodiment, the required voltage charges the polarized capacitor C1 through the first diode D1 and the first resistor R1. When no gas leak is detected, the microcontroller's I / O port is at a high level, the second transistor V2 is turned on, the first transistor V1 is turned off, the MOSFET is turned off, and the solenoid valve does not operate, i.e., the solenoid valve is in the on state. When a gas leak is detected, the microcontroller's I / O port is at a low level, the second transistor V2 is turned off, and the first transistor V1 is turned on under the action of the fifth resistor R5. Then the MOSFET is turned on, and the energy stored in the polarized capacitor C1 is supplied to the solenoid valve through the MOSFET. The solenoid valve then operates, shutting off the gas supply.

[0037] When the mains power is disconnected, the microcontroller's power supply is cut off. The first polarized capacitor C1, which had been charged before the power was cut off, no longer outputs any level signal from the microcontroller's I / O port. This causes the base of the second transistor V2 to be pulled low by the sixth resistor R6, thus turning off the second transistor. The first transistor V1 and the MOSFET are turned on by the fifth resistor R5. The first polarized capacitor C1 discharges through the MOSFET to the solenoid valve, causing the solenoid valve to close automatically. This ensures that the gas supply is shut off in time during the power outage, preventing any danger.

[0038] This invention adds only two resistors, one transistor, and one diode, all of which are SMT packaged, making them small enough to fit on the original circuit board. The circuit can be placed inside an alarm with a wired output control solenoid valve or at the wireless valve control terminal. The circuit is simple and easy to implement, allowing for easy power-off valve closure without additional manual operation, thus ensuring gas safety.

[0039] Furthermore, by setting a first diode D1 at the input terminal, this embodiment helps to prevent current backflow when the first capacitor C1 discharges, thereby further improving the performance of the solenoid valve drive circuit.

[0040] In this embodiment, the microcontroller is an STM32 series microcontroller.

[0041] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A circuit for shutting off a solenoid valve upon power failure, characterized in that, include: Voltage conversion module, microcontroller, solenoid valve drive circuit and solenoid valve; The microcontroller and solenoid valve drive circuit are connected to the mains power supply through a voltage conversion module to convert the mains voltage into the voltage required by the microcontroller and solenoid valve drive circuit; the microcontroller is connected to the solenoid valve through the solenoid valve drive circuit. The solenoid valve drive circuit includes: a first resistor R1 and a fifth resistor R5; the first ends of the first resistor R1 and the fifth resistor R5 are connected to the first output terminal of the voltage conversion module; the second end of the first resistor R1 is connected to the positive terminal of the first polarized capacitor C1, the first end of the second resistor R2, and the source of the MOSFET; the negative terminal of the first polarized capacitor C1 is grounded; the second end of the second resistor R2 is connected to the gate of the MOSFET and the first end of the third resistor R3; the second end of the third resistor R3 is connected to the collector of the first transistor V1; the base of the first transistor V1 is connected to the second end of the fifth resistor R5 and the collector of the second transistor V2; the emitter of the first transistor is grounded; the base of the second transistor V2 is connected to the first end of the fourth resistor R4; the second end of the fourth resistor R4 is connected to the I / O port of the microcontroller and the first end of the sixth resistor R6; the second end of the sixth resistor R6 and the emitter of the second transistor V2 are grounded; the drain of the MOSFET is connected to port C+ of connector JP1 for connection with the solenoid valve; port C- of connector JP1 is grounded.

2. The circuit for shutting off the solenoid valve upon power failure according to claim 1, characterized in that, The microcontroller is an STM32 series microcontroller.

3. The circuit for shutting off the solenoid valve upon power failure according to claim 1, characterized in that, The solenoid valve drive circuit includes: a first diode D1, and the first output terminal of the voltage conversion module is connected to the first terminal of the first resistor R1 and the first terminal of the fifth resistor R5 through the first diode D1.

4. The circuit for shutting off the solenoid valve upon power failure according to claim 1, characterized in that, The solenoid valve drive circuit is packaged on a substrate using SMT packaging technology.

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