Methane alarm detector

Abstract

The application provides a methane alarm detector, which comprises a shell and a methane sensor, a battery unit, a voltage conversion unit, a signal processing unit and a processor arranged in the shell. The signal processing unit comprises a signal acquisition circuit connected with the methane sensor, which is used for acquiring an output voltage of the methane sensor and outputting a first detection signal; a signal amplification circuit, which is used for amplifying the first detection signal and outputting a second detection signal; a bias voltage circuit connected with the signal amplification circuit, which is used for providing positive and negative bias voltages for the signal amplification circuit; and a clamping filter circuit connected with the signal amplification circuit and the processor, which is used for filtering and clamping the second detection signal and outputting a third detection signal to the processor. The processor calculates a methane concentration value according to the third detection signal and outputs an alarm signal when the methane concentration value is greater than a threshold value. The application is powered by the battery unit, is more convenient to use and improves the alarm accuracy.

Description

Technical Field

[0001] This application relates to the field of gas detection, and in particular to a methane alarm detector. Background Technology

[0002] A methane alarm detector is a device that detects or quantifies the amount of methane in the air using an appropriate electrical signal. When a combustible gas is present in the environment where the methane alarm detector is located, the conductivity of the sensor increases with the increase of the methane gas concentration in the air.

[0003] Existing methane alarm detectors are powered by AC220V mains electricity, so it is necessary to pre-bury wiring and install AC220V sockets in corresponding locations such as the kitchen, which increases the complexity of house design and construction and the cost of renovation. Utility Model Content

[0004] Therefore, it is necessary to provide a methane alarm detector to address the aforementioned technical problems.

[0005] This application provides a methane alarm detector, including a housing and a methane sensor, a battery unit, a voltage conversion unit, a signal processing unit, and a processor disposed within the housing. The methane sensor, the signal processing unit, and the processor are connected sequentially. The voltage conversion unit is connected to the battery unit, the methane sensor, the signal processing unit, and the processor. The signal processing unit includes: A signal acquisition circuit, connected to the methane sensor, is used to acquire the output voltage of the methane sensor and output a first detection signal; A signal amplification circuit, connected to the signal acquisition circuit, is used to amplify the first detection signal and output a second detection signal. A bias voltage circuit, connected to the signal amplification circuit, is used to provide positive and negative bias voltages to the signal amplification circuit; A clamping filter circuit, connected to the signal amplification circuit and the processor, is used to filter and clamp the second detection signal and output a third detection signal to the processor. The processor calculates the methane concentration value based on the third detection signal and outputs an alarm signal when the methane concentration value is greater than a threshold.

[0006] In some embodiments, the signal acquisition circuit includes a voltage follower U9B, wherein the first detection signal is input to the non-inverting input terminal of the voltage follower U9B, and the output terminal is connected to the inverting input terminal to output the second detection signal.

[0007] In some embodiments, the signal amplification circuit includes an operational amplifier U9A, resistors R52, R53, and R54. The non-inverting input terminal of the operational amplifier U9A is connected to one end of resistor R53 and the positive bias voltage provided by the bias voltage circuit. The other end of resistor R53 is used to input the second detection signal. The inverting input terminal is connected to one end of resistors R52 and R54. The other end of resistor R52 is connected to the negative bias voltage provided by the bias voltage circuit. The other end of resistor R54 is connected to the output terminal of the operational amplifier U9A.

[0008] In some embodiments, the bias voltage circuit includes a positive bias voltage circuit and a negative bias voltage circuit, the positive bias voltage circuit being connected to the non-inverting input terminal of the operational amplifier U9A, and the negative bias voltage circuit being connected to the resistor R52.

[0009] In some embodiments, the positive bias voltage circuit includes an operational amplifier U8B, resistors R55, R60, and R64. The non-inverting input terminal of the operational amplifier U8B is connected to one end of resistors R64 and R60, the other end of resistor R64 is connected to a common ground, the other end of resistor R60 is connected to the voltage conversion unit, the output terminal of the operational amplifier U8B is connected to its inverting input terminal and one end of resistor R55, and the other end of resistor R55 is connected to the non-inverting input terminal of the operational amplifier U9A. The negative bias voltage circuit includes an operational amplifier U8A, a resistor R10, and a resistor R18. The non-inverting input terminal of the operational amplifier U8A is connected to one end of the resistors R10 and R18. The other end of the resistor R18 is connected to a common ground. The other end of the resistor R10 is connected to the voltage conversion unit. The output terminal of the operational amplifier U8B is connected to its inverting input terminal and one end of the resistor R52.

[0010] In some embodiments, the clamping filter circuit includes a filter circuit and a clamping circuit connected in sequence.

[0011] In some embodiments, the filter circuit includes a resistor R51 and a capacitor C47. One end of the resistor R51 is connected to the signal amplification circuit, and the other end of the resistor R51 is connected to one end of the capacitor C47. The other end of the capacitor C47 is connected to a common ground. The clamping circuit includes a clamping device D23, with its first terminal connected to a common ground, its second terminal connected to a clamping voltage, and its third terminal connected to the filter circuit.

[0012] In some embodiments, the processor also outputs pulse signals to control the methane sensor to operate intermittently.

[0013] In some embodiments, the processor further determines whether the methane sensor is short-circuited or open-circuited based on the third detection signal.

[0014] In some embodiments, the housing includes a first component and a second component, the first component and the second component being detachably connected.

[0015] The above-mentioned methane alarm detector has the following technical advantages: 1. Powering other modules via battery units eliminates the need for modifications to the building's wiring compared to existing technologies, making it more convenient to use and enabling methane detection even in environments without mains power.

[0016] 2. The output voltage of the methane sensor is acquired using a signal acquisition circuit, and a first detection signal is output. The first detection signal is amplified using a signal amplification circuit, and a second detection signal is output. A bias voltage circuit provides positive and negative bias voltages to the signal amplification circuit. The second detection signal is filtered and clamped using a clamping filter circuit, and a third detection signal is output to the processor. The above circuit design improves the accuracy of the detection signal, thereby improving the accuracy of the methane alarm detector. Attached Figure Description

[0017] Figure 1 Schematic diagrams of module connections for methane alarm detectors provided in some embodiments of this application; Figure 2 Circuit diagrams of methane sensors provided in some embodiments of this application; Figure 3 Circuit diagrams of voltage conversion units provided in some embodiments of this application; Figure 4 The circuit schematics of the signal processing unit are provided in some embodiments of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application. Furthermore, it is understood that although the efforts made in such a development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, modifications to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0019] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0020] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application means two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The terms “first,” “second,” “third,” etc., used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0021] Figure 1 The diagram shows the module connection of the methane alarm detector in some embodiments provided in this application. Figure 1 As shown, the methane alarm detector includes a housing and a methane sensor, a battery unit, a voltage conversion unit, a signal processing unit, and a processor disposed within the housing. The methane sensor, the signal processing unit, and the processor are connected in sequence, and the voltage conversion unit is connected to the battery unit, the methane sensor, the signal processing unit, and the processor.

[0022] In this embodiment, the battery unit provides the power supply voltage, and the voltage conversion unit boosts the power supply voltage to power other modules. Compared with the prior art, it does not require modification of the house wiring, making it more convenient to use and enabling methane detection in environments without mains power.

[0023] The housing features a detachable design for easy replacement of the battery unit. It includes a first component and a second component, which are detachably connected.

[0024] For example, the second component is mounted on the wall by studs, the second component is provided with a hook, and the first component is provided with a groove corresponding to the hook, and the two are connected to each other.

[0025] The signal processing unit includes: a signal acquisition circuit connected to the methane sensor, used to acquire the output voltage of the methane sensor and output a first detection signal; a signal amplification circuit connected to the signal acquisition circuit, used to amplify the first detection signal and output a second detection signal; a bias voltage circuit connected to the signal amplification circuit, used to provide positive and negative bias voltages to the signal amplification circuit; and a clamping filter circuit connected to the signal amplification circuit and the processor, used to filter and clamp the second detection signal and output a third detection signal to the processor, wherein the processor calculates the methane concentration value based on the third detection signal and outputs an alarm signal when the methane concentration value is greater than a threshold.

[0026] The bias voltage circuit adds positive and negative bias voltages to eliminate the inherent positive and negative voltages of the methane sensor, aiming to eliminate errors and improve detection accuracy. Simultaneously, the clamping filter circuit filters and clamps the second detection signal, further improving detection accuracy.

[0027] Figure 2 The circuit diagrams of the methane sensor provided in some embodiments of this application are shown below. Figure 2 As shown, it includes a sensing element Rf, a resistor Rd, and a resistor RL. Here, +4.4V_Sensor is the supply voltage output by the voltage conversion unit, VH is the pulse signal output by the processor, and VS is the output voltage of the methane sensor.

[0028] The sensitive element Rf is sensitive to methane concentration. When the methane concentration changes, its equivalent resistance changes, thereby altering its output voltage VS. The processor outputs a pulse signal VH to control the methane sensor to operate intermittently. For example, the methane sensor is controlled to turn on for 0.13 seconds every 20 seconds. During this 0.13 seconds, the output voltage VS is sampled. If there is a methane gas leak, the VS voltage value will change. Low power consumption is achieved through extremely short pulse supply time.

[0029] Figure 3 The circuit diagrams of the voltage conversion units provided in some embodiments of this application are shown below. Figure 3As shown, the voltage conversion unit includes a voltage conversion chip U7, resistors R19, R48, R49, and R50, capacitors C10, C11, and C17, and inductor L3.

[0030] The voltage conversion chip U7, for example, is an ultra-low power BOOST chip that converts the 3.0V voltage provided by the battery cell into a 4.4V voltage output.

[0031] Figure 4 The circuit schematics of the signal processing unit are provided in some embodiments of this application.

[0032] The signal acquisition circuit includes a voltage follower U9B, the first detection signal is input to the non-inverting input terminal of the voltage follower U9B, and the output terminal is connected to the inverting input terminal to output the second detection signal.

[0033] The signal amplification circuit includes an operational amplifier U9A, resistors R52, R53, and R54. The non-inverting input of the operational amplifier U9A is connected to one end of resistor R53 and the positive bias voltage provided by the bias voltage circuit. The other end of resistor R53 is used to input the second detection signal. The inverting input is connected to one end of resistors R52 and R54. The other end of resistor R52 is connected to the negative bias voltage provided by the bias voltage circuit. The other end of resistor R54 is connected to the output of the operational amplifier U9A.

[0034] The bias voltage circuit includes a positive bias voltage circuit and a negative bias voltage circuit. The positive bias voltage circuit is connected to the non-inverting input terminal of the operational amplifier U9A, and the negative bias voltage circuit is connected to the resistor R52.

[0035] The positive bias voltage circuit includes an operational amplifier U8B, resistors R55, R60, and R64. The non-inverting input terminal of the operational amplifier U8B is connected to one end of resistors R64 and R60. The other end of resistor R64 is connected to common ground. The other end of resistor R60 is connected to the voltage conversion unit. The output terminal of the operational amplifier U8B is connected to its inverting input terminal and one end of resistor R55. The other end of resistor R55 is connected to the non-inverting input terminal of the operational amplifier U9A.

[0036] The negative bias voltage circuit includes an operational amplifier U8A, a resistor R10, and a resistor R18. The non-inverting input terminal of the operational amplifier U8A is connected to one end of the resistors R10 and R18. The other end of the resistor R18 is connected to a common ground. The other end of the resistor R10 is connected to the voltage conversion unit. The output terminal of the operational amplifier U8B is connected to its inverting input terminal and one end of the resistor R52.

[0037] The clamping filter circuit includes a filter circuit and a clamping circuit connected in sequence.

[0038] The filter circuit includes a resistor R51 and a capacitor C47. One end of the resistor R51 is connected to the signal amplification circuit, and the other end of the resistor R51 is connected to one end of the capacitor C47. The other end of the capacitor C47 is connected to the common ground.

[0039] The clamping circuit includes a clamping device D23, the first terminal of which is connected to the common ground, the second terminal of which is connected to the clamping voltage, and the third terminal of which is connected to the filter circuit.

[0040] U4 is a methane sensor. Operational amplifiers U8A, U8B, U9A, and U9B all use low-power operational amplifier chips to reduce the power consumption of the methane alarm detector in a static state.

[0041] The signal acquisition circuit acquires the output voltage VS of the methane sensor U4 via a voltage follower U9B, outputting the first detection signal Vi. The voltage follower U9B ensures signal integrity and stability. Operational amplifier U9A amplifies the first detection signal Vi, which then passes through a filter circuit and a clamping circuit to output the third detection signal Vo. The filter circuit removes unnecessary frequency components from the signal, retaining only the desired signal components, thus improving signal quality. The clamping circuit controls the output range of the third detection signal Vo, preventing it from becoming too large and damaging the processor. Positive and negative bias voltage circuits provide positive and negative bias voltages to the signal amplification circuit, causing it to output a positive second detection signal.

[0042] The processor calculates the methane concentration value based on the third detection signal and outputs an alarm signal, such as a beeping sound, when the methane concentration value is greater than the threshold.

[0043] In some embodiments, the processor also determines whether the methane sensor is short-circuited or open-circuited based on a third detection signal.

[0044] like Figure 4 As shown, when pins 1 and 3 of the methane sensor U4 are short-circuited, the first detection signal Vi = 4.4V; when pins 2 and 3 or pins 1 and 2 of the methane sensor U4 are short-circuited, the first detection signal Vi = 0; when pins 1 and 3 of the methane sensor U4 are open-circuited, the first detection signal Vi = 0; and when pins 2 and 3 of the methane sensor U4 are open-circuited, the first detection signal Vi = 4.4V. The third detection signal Vo is used to characterize the first detection signal Vi, therefore the processor can realize fault detection of the methane sensor U4 based on the third detection signal Vo.

[0045] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The above embodiments merely illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A methane alarm detector, characterized in that, The system includes a housing and a methane sensor, a battery unit, a voltage conversion unit, a signal processing unit, and a processor disposed within the housing. The methane sensor, the signal processing unit, and the processor are connected sequentially. The voltage conversion unit is connected to the battery unit, the methane sensor, the signal processing unit, and the processor. The signal processing unit includes: A signal acquisition circuit, connected to the methane sensor, is used to acquire the output voltage of the methane sensor and output a first detection signal; A signal amplification circuit, connected to the signal acquisition circuit, is used to amplify the first detection signal and output a second detection signal. A bias voltage circuit, connected to the signal amplification circuit, is used to provide positive and negative bias voltages to the signal amplification circuit; A clamping filter circuit, connected to the signal amplification circuit and the processor, is used to filter and clamp the second detection signal and output a third detection signal to the processor. The processor calculates the methane concentration value based on the third detection signal and outputs an alarm signal when the methane concentration value is greater than a threshold.

2. The methane alarm detector according to claim 1, characterized in that, The signal acquisition circuit includes a voltage follower U9B, the first detection signal is input to the non-inverting input terminal of the voltage follower U9B, and the output terminal is connected to the inverting input terminal to output the second detection signal.

3. The methane alarm detector according to claim 1, characterized in that, The signal amplification circuit includes an operational amplifier U9A, resistors R52, R53, and R54. The non-inverting input of the operational amplifier U9A is connected to one end of resistor R53 and the positive bias voltage provided by the bias voltage circuit. The other end of resistor R53 is used to input the second detection signal. The inverting input is connected to one end of resistors R52 and R54. The other end of resistor R52 is connected to the negative bias voltage provided by the bias voltage circuit. The other end of resistor R54 is connected to the output of the operational amplifier U9A.

4. The methane alarm detector according to claim 3, characterized in that, The bias voltage circuit includes a positive bias voltage circuit and a negative bias voltage circuit. The positive bias voltage circuit is connected to the non-inverting input terminal of the operational amplifier U9A, and the negative bias voltage circuit is connected to the resistor R52.

5. The methane alarm detector according to claim 4, characterized in that, The positive bias voltage circuit includes an operational amplifier U8B, resistors R55, R60, and R64. The non-inverting input terminal of the operational amplifier U8B is connected to one end of resistors R64 and R60. The other end of resistor R64 is connected to common ground. The other end of resistor R60 is connected to the voltage conversion unit. The output terminal of the operational amplifier U8B is connected to its inverting input terminal and one end of resistor R55. The other end of resistor R55 is connected to the non-inverting input terminal of the operational amplifier U9A. The negative bias voltage circuit includes an operational amplifier U8A, a resistor R10, and a resistor R18. The non-inverting input terminal of the operational amplifier U8A is connected to one end of the resistors R10 and R18. The other end of the resistor R18 is connected to a common ground. The other end of the resistor R10 is connected to the voltage conversion unit. The output terminal of the operational amplifier U8B is connected to its inverting input terminal and one end of the resistor R52.

6. The methane alarm detector according to claim 1, characterized in that, The clamping filter circuit includes a filter circuit and a clamping circuit connected in sequence.

7. The methane alarm detector according to claim 6, characterized in that, The filtering circuit includes a resistor R51 and a capacitor C47. One end of the resistor R51 is connected to the signal amplification circuit, and the other end of the resistor R51 is connected to one end of the capacitor C47. The other end of the capacitor C47 is connected to the common ground. The clamping circuit includes a clamping device D23, with its first terminal connected to a common ground, its second terminal connected to a clamping voltage, and its third terminal connected to the filter circuit.

8. The methane alarm detector according to claim 1, characterized in that, The processor also outputs pulse signals to control the methane sensor to operate intermittently.

9. The methane alarm detector according to claim 1, characterized in that, The processor also determines whether the methane sensor is short-circuited or open-circuited based on the third detection signal.

10. The methane alarm detector according to claim 1, characterized in that, The housing includes a first component and a second component, which are detachably connected.

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