Flame sensing circuit and gas combustion device

Abstract

The utility model relates to flame detection technical field discloses flame perception circuit and gas combustion equipment, the utility model is applied to the gas combustion equipment with controller, include: flame detection electrode for accessing flame ion signal, AD conversion circuit and analog signal detection circuit, wherein, the input of AD conversion circuit is connected with flame detection electrode, and the output is connected with the digital signal receiving port of controller, the input of analog signal detection circuit is connected with flame detection electrode, and the output is connected with the analog signal receiving port of controller, in the utility model, flame perception circuit can combine AD conversion circuit and analog signal detection circuit, realizes the fast and accurate of combustion state detection.

Description

Technical Field

[0001] This utility model relates to the field of flame detection technology, and in particular to a flame sensing circuit and a gas combustion device. Background Technology

[0002] To ensure safe combustion in gas products, flame ionization current is typically detected to determine the combustion state. In related technologies, a threshold is usually set in the processor, and the collected flame ionization signal is compared with this threshold to determine the presence of a flame. However, this method can only simply determine the presence of a flame; it cannot analyze the specific state of the flame. This can lead to false positives due to momentary fluctuations in flame intensity, resulting in low accuracy and reliability in flame detection. Utility Model Content

[0003] The first technical problem solved by this invention is to provide a flame sensing circuit that helps improve the accuracy and reliability of flame detection.

[0004] The second technical problem solved by this invention is to provide a gas combustion device that helps improve the accuracy and reliability of flame detection.

[0005] The first technical problem mentioned above is solved by the following technical solution:

[0006] A flame sensing circuit is applied to a gas combustion device with a controller; the flame sensing circuit includes:

[0007] Flame detection electrode, used to receive flame ionization signals;

[0008] Analog-to-digital converter circuit and analog signal detection circuit;

[0009] The input terminal of the analog-to-digital converter circuit is connected to the flame detection electrode, and the output terminal is connected to the digital signal receiving port of the controller to output a high level or a low level to the controller.

[0010] The input terminal of the analog signal detection circuit is connected to the flame detection electrode, and the output terminal is connected to the analog signal receiving port of the controller.

[0011] Compared with the prior art, the flame sensing circuit of this invention has the following advantages: By simultaneously outputting analog and digital signals through an analog signal detection circuit and an analog-to-digital converter circuit, when the combustion state of the gas combustion device changes, the analog-to-digital converter circuit can quickly detect the change in combustion state and reflect it in the output digital signal. For example, when the combustion state changes from burning to extinguishing, the output digital signal quickly changes from low level to high level, enabling the controller to quickly detect whether there is a flame in the gas combustion device based on the digital signal output by the analog-to-digital converter circuit. Furthermore, since the controller only makes judgments based on the digital signal, it is relatively stable and less susceptible to interference. Meanwhile, the analog signal detection circuit can accurately detect changes in flame size and continuously output analog signals that reflect the current flame size, allowing the controller to accurately determine the flame size of the gas combustion device through the analog signals output by the analog signal detection circuit. Therefore, this flame sensing circuit, by combining the analog-to-digital converter circuit and the analog signal detection circuit, achieves rapid and accurate detection of the combustion state. In addition, the gas proportional valve can be closed in a timely manner based on the digital signal detected by the analog-to-digital converter circuit, and the opening degree of the gas proportional valve can be adjusted based on the analog signal detected by the analog signal detection circuit. As can be seen, this utility model provides a hardware architecture that helps to achieve both rapid and accurate flame detection in combustion devices.

[0012] In one embodiment, the analog-to-digital conversion circuit includes: a signal determination unit, the signal determination unit including a DC power supply and a first resistor;

[0013] One end of the first resistor is connected to a DC power supply, and the other end is connected to a flame detection electrode.

[0014] In one embodiment, the signal determination unit further includes a second resistor and a first capacitor;

[0015] One end of the second resistor is connected to one end of the first resistor, one end of the first capacitor, and the flame detection electrode, while the other end is connected to the digital signal receiving port of the controller.

[0016] The other end of the first capacitor is grounded.

[0017] In one embodiment, the analog-to-digital conversion circuit further includes a voltage clamping unit, which includes a first diode and a second diode;

[0018] In this configuration, the first end of the first diode is connected to the DC power supply, and the second end is connected to the other end of the first resistor and the first end of the second diode.

[0019] The other end of the second diode is grounded.

[0020] In one embodiment, the analog-to-digital conversion circuit further includes a third resistor and a fourth resistor;

[0021] Among them, one end of the third resistor is connected to the other end of the first resistor and one end of the fourth resistor, and the other end is connected to the flame detection electrode.

[0022] The other end of the fourth resistor is grounded.

[0023] In one embodiment, the circuit further includes an AC power supply circuit, which includes an AC power source and a second capacitor; the analog-to-digital conversion circuit also includes a fifth resistor.

[0024] Among them, one end of the fifth resistor is connected to the other end of the first resistor and one end of the second capacitor, and the other end is connected to the flame detection electrode.

[0025] The other end of the second capacitor is connected to one end of the AC power supply.

[0026] The other end of the AC power supply is grounded.

[0027] In one embodiment, the analog signal detection circuit includes an operational amplifier, a sixth resistor, and a seventh resistor;

[0028] The operational amplifier's first input terminal is connected to one end of the sixth resistor and the other end of the seventh resistor, its second input terminal is grounded, and its output terminal is connected to the other end of the seventh resistor and the analog signal receiving port of the controller.

[0029] The other end of the sixth resistor is connected to the flame detection electrode.

[0030] In one embodiment, the analog signal detection circuit further includes an eighth resistor and a third capacitor;

[0031] Among them, one end of the eighth resistor is connected to the other end of the sixth resistor and one end of the third capacitor, and the other end is connected to the flame detector.

[0032] The other end of the third capacitor is connected to the second input terminal of the operational amplifier and grounded.

[0033] In one embodiment, the circuit further includes an AC power supply circuit, which includes an AC power source and a fourth capacitor; the analog signal detection circuit further includes a ninth resistor.

[0034] Among them, one end of the ninth resistor is connected to the other end of the sixth resistor and one end of the fourth capacitor, and the other end is connected to the flame detection electrode.

[0035] The other end of the fourth capacitor is connected to one end of the AC power supply.

[0036] The second technical problem mentioned above is solved by the following technical solution:

[0037] A gas combustion device includes a flame sensing circuit, a controller, and a gas proportional valve as described in any of the above embodiments; the digital signal receiving port of the controller is electrically connected to the output terminal of the analog-to-digital conversion circuit, the analog signal receiving port of the controller is electrically connected to the output terminal of the analog signal detection circuit, and the control terminal of the controller is electrically connected to the gas proportional valve. Attached Figure Description

[0038] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the structure of a flame sensing circuit according to an embodiment of the present invention;

[0040] Figure 2 This is a circuit diagram of a flame sensing circuit according to an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Analog-to-digital conversion circuit; 11. Signal determination unit; 12. Voltage clamping unit; 2. Analog signal detection circuit; 3. AC power supply circuit. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0045] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0047] To ensure safe combustion in gas products, flame ionization current is typically detected to determine the combustion state. In related technologies, a threshold is usually set in the processor, and the collected flame ionization signal is compared with this threshold to determine the presence of a flame. However, this method can only simply determine the presence of a flame; it cannot analyze the specific state of the flame. This can lead to false positives due to momentary fluctuations in flame intensity, resulting in low accuracy and reliability in flame detection. Furthermore, this method is susceptible to interference from the controller's power supply module, placing high demands on the controller chip and further reducing the accuracy and reliability of flame detection.

[0048] Based on this, the present invention provides a flame sensing circuit that simultaneously outputs analog and digital signals through an analog signal detection circuit and an analog-to-digital converter (ADC). When the combustion state of the gas combustion device changes, the ADC can quickly detect the change and reflect it in the output digital signal. For example, when the combustion state changes from burning to extinguishing, the output digital signal quickly changes from low to high level. This allows the controller to quickly detect whether there is a flame in the gas combustion device based on the digital signal output by the ADC. Since the controller only makes judgments based on the digital signal, it is relatively stable and not easily affected by interference. The analog signal detection circuit can accurately detect changes in flame size and continuously outputs an analog signal that reflects the current flame size. Thus, the controller can accurately determine the flame size of the gas combustion device through the analog signal output by the analog signal detection circuit. Therefore, this flame sensing circuit, by combining the ADC and analog signal detection circuits, achieves rapid and accurate detection of the combustion state. In addition, the gas proportional valve can be closed in a timely manner based on the digital signal detected by the ADC, and the opening of the gas proportional valve can be adjusted based on the analog signal detected by the analog signal detection circuit. As can be seen, this utility model provides a hardware architecture that helps to achieve both rapid and accurate flame detection in combustion devices.

[0049] The following is combined Figures 1 to 2 The following describes embodiments of the present invention.

[0050] According to an embodiment of the present invention, a flame sensing circuit is provided, which can be applied to a gas combustion device with a controller to detect the flame ion signal of the gas combustion device. Figure 1 This is a schematic diagram of the structure of a flame sensing circuit according to an embodiment of the present invention, as shown below. Figure 1 As shown, the flame sensing circuit includes: a flame detection electrode J1, an analog-to-digital converter circuit 1, and an analog signal detection circuit 2. The flame detection electrode J1 is used to receive flame ionization signals. The input terminal of the analog-to-digital converter circuit 1 is connected to the flame detection electrode J1, and its output terminal is connected to the digital signal receiving port of the controller to output a high or low level to the controller. The presence of a flame ionization signal is determined by the level. The input terminal of the analog signal detection circuit 2 is connected to the flame detection electrode J1, and its output terminal is connected to the analog signal receiving port of the controller. The analog signal detection circuit 2 and the analog-to-digital converter circuit 1 detect the flame ionization signals respectively and send the detection results to the controller. The controller can combine the detection results of the analog signal detection and the analog-to-digital converter circuit 1 to perform flame detection and identification, thereby accurately determining the flame combustion state and improving the accuracy and reliability of flame detection.

[0051] In one embodiment, Figure 2This is a circuit diagram of a flame sensing circuit according to an embodiment of the present invention, as shown below. Figure 2 As shown, the analog-to-digital conversion circuit 1 includes a signal determination unit 11, which comprises a DC power supply and a first resistor R1. One end of the first resistor R1 is connected to the DC power supply, and the other end is connected to the flame detection electrode J1. When there is no flame ionization signal, no current loop is formed in the signal determination unit 11, and the voltage output to the digital signal receiving port of the controller is equal to the voltage of the DC power supply, resulting in a high level at the controller's digital signal receiving port. When there is a flame ionization signal, the signal is input to the analog-to-digital conversion circuit 1, creating a current loop. The DC power supply generates current through the first resistor R1, forming a voltage divider on the DC power supply voltage, thereby reducing the voltage output to the controller's digital signal receiving port, resulting in a low level at the controller's digital signal receiving port. Thus, the presence or absence of a flame ionization signal can be determined by the level at the digital signal receiving port.

[0052] In one embodiment, such as Figure 2 As shown, the signal determination unit 11 also includes a second resistor R2 and a first capacitor C1. One end of the second resistor R2 is connected to one end of the first resistor R1, one end of the first capacitor C1, and the flame detection electrode J1; the other end is connected to the digital signal receiving port of the controller. The other end of the first capacitor C1 is grounded. The first capacitor C1 and the second resistor R2 form a current-limiting filter circuit, which controls the signal output by the signal determination unit 11 within the digital signal receiving range of the controller, while filtering out spike interference to form a stable signal value.

[0053] In one embodiment, such as Figure 2 As shown, the analog-to-digital conversion circuit 1 further includes a voltage clamping unit 12, which includes a first diode D1 and a second diode D2. The first diode D1 and the second diode D2 are used to limit the voltage peak generated on the signal determination unit 11. The first end of the first diode D1 is connected to the DC power supply, and the second end is connected to the other end of the first resistor R1 and the first end of the second diode D2. The other end of the second diode D2 is grounded.

[0054] In one embodiment, such as Figure 2 As shown, the analog-to-digital converter circuit 1 also includes a third resistor R3 and a fourth resistor R4. One end of the third resistor R3 is connected to the other end of the first resistor R1 and one end of the fourth resistor R4, and the other end is connected to the flame detection electrode J1; the other end of the fourth resistor R4 is grounded.

[0055] In one embodiment, such as Figure 2As shown, the circuit also includes an AC power supply circuit 3, which includes an AC power source and a second capacitor C2. Correspondingly, the analog-to-digital conversion circuit 1 also includes a fifth resistor R5. One end of the fifth resistor R5 is connected to the other end of the first resistor R1 and one end of the second capacitor C2, and the other end is connected to the flame detection electrode J1. The other end of the second capacitor C2 is connected to one end of the AC power source, and the other end of the AC power source is grounded. When there is no flame, that is, when no flame ionization signal is formed, the AC power source does not form a current loop through the second capacitor C2 and the fifth resistor R5. At this time, no signal enters the signal determination unit 11, and the voltage output from the signal determination unit 11 to the controller is the DC power supply voltage. The digital signal receiving port of the controller is at a high level. When a combustion flame is present, the AC power supply provides power to the analog-to-digital conversion circuit 1 through the second capacitor C2. The flame ionization signal reaches the signal determination unit 11 through the third resistor R3. The DC power supply in the signal determination unit 11 generates current through the first resistor R1 to form a determination circuit. The first resistor R1 divides the voltage to reduce the voltage output to the controller. At the same time, the voltage clamping unit 12 clamps and limits the peak value of the output of the signal determination unit 11. Finally, the output is sent to the controller through the digital signal receiving port. At this time, the digital signal receiving port of the controller is at a low level.

[0056] In one embodiment, the signal received by the controller from the digital signal receiving port is a determination signal for the flame ion signal. At the same time, the controller internally sets a preset determination value for the determination signal. After receiving the determination signal, it is compared with the preset determination value. If the determination signal exceeds the preset determination value, it is determined that there is no combustion flame. If the determination signal is lower than the preset determination value, it is determined that there is a combustion flame.

[0057] In one embodiment, such as Figure 2 As shown, the analog signal detection circuit 2 includes an operational amplifier U1, a sixth resistor R6, and a seventh resistor R7. Operational amplifier U1, sixth resistor R6, and seventh resistor R7 constitute an inverting amplifier to amplify the flame ionization signal. The first input terminal of operational amplifier U1 is connected to one end of the sixth resistor R6 and the other end of the seventh resistor R7, the second input terminal is grounded, and the output terminal is connected to the other end of the seventh resistor R7 and the analog signal receiving port of the controller. The other end of the sixth resistor R6 is connected to the flame detection electrode J1.

[0058] In one embodiment, such as Figure 2As shown, the analog signal detection circuit 2 also includes an eighth resistor R8 and a third capacitor C3. One end of the eighth resistor R8 is connected to the other end of the sixth resistor R6 and one end of the third capacitor C3, while the other end is connected to the flame detection circuit. The other end of the third capacitor C3 is connected to the second input terminal of the operational amplifier U1 and grounded. The eighth resistor R8 and the third capacitor C3 form a filter circuit to filter out spike interference in the flame ion signal, resulting in a stable flame signal value.

[0059] In one embodiment, such as Figure 2 Figure 2 As shown, the circuit also includes an AC power supply circuit 3, which includes an AC power source and a fourth capacitor C4. Correspondingly, the analog signal detection circuit 2 also includes a ninth resistor R9. One end of the ninth resistor R9 is connected to the other end of the sixth resistor R6 and one end of the fourth capacitor C4, while the other end is connected to the flame detection electrode J1. The other end of the fourth capacitor C4 is connected to one end of the AC power source. When there is no combustion flame, i.e., no flame ionization signal is formed, the AC power supply passes through the fourth capacitor C4 and the ninth resistor R9, and no signal enters the analog signal detection circuit 2; the controller's analog signal receiving port is at a low level. When a combustion flame is present, the AC power supply provides power to the analog signal detection circuit 2 through the fourth capacitor C4. The analog signal detection circuit 2 amplifies the detected flame ionization signal and outputs it to the controller's analog signal receiving port.

[0060] In one embodiment, when the controller performs flame detection and determination based on the detection signals output by the analog signal detection circuit 2 and the digital signal circuit, if the detection signal output by the analog signal detection circuit 2 is low and the detection signal output by the analog-to-digital converter circuit 1 is high, then it is determined that there is no burning flame; if the signal output by the analog signal detection circuit 2 is high and the detection signal output by the analog-to-digital converter circuit 1 is low, then it is determined that there is a burning flame; if the signal output by the analog signal detection circuit 2 is high, but the detection signal output by the analog-to-digital converter circuit 1 is high, then it is determined that the current analog signal detection circuit 2 is experiencing interference-induced misjudgment, or that the current flame intensity is too low to meet the combustion standard, and it is determined that there is no burning flame at this time.

[0061] The flame sensing circuit provided by this utility model includes a controller that can simultaneously receive analog detection signals detected by an analog signal detection circuit and digital detection signals detected by an analog-to-digital converter (ADC). When the combustion state of the gas combustion device changes, the ADC can quickly detect the change from combustion to extinguishment and reflect this in the digital detection signal. This allows the controller to quickly detect the presence or absence of a flame in the gas combustion device based on the digital detection signal detected by the ADC. The analog signal detection circuit can accurately detect changes in flame size and real-time combustion state, thus accurately reflecting the flame size and real-time combustion state of the gas combustion device to the controller through the detected analog detection signal. Therefore, by combining the ADC and analog signal detection circuits, rapid and accurate detection of the combustion state can be achieved, improving the accuracy and reliability of flame detection. Furthermore, the gas proportional valve can be closed in a timely manner based on the digital detection signal detected by the ADC, and the opening of the gas proportional valve can be adjusted based on the analog detection signal detected by the analog signal detection circuit. Therefore, this utility model provides a hardware architecture that helps improve the accuracy of flame detection in combustion devices and the precise control of the gas proportional valve.

[0062] According to an embodiment of the present invention, another aspect provides a gas combustion device, including a flame sensing circuit, a controller, and a proportional valve as described in any of the above embodiments; the digital signal receiving port of the controller is electrically connected to the output terminal of the analog-to-digital conversion circuit, the analog signal receiving port of the controller is electrically connected to the output terminal of the analog signal detection circuit, and the control terminal of the controller is electrically connected to the gas proportional valve.

[0063] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0064] The specific embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are detailed, they should not be construed as limiting the scope of this 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 utility model, and these modifications and improvements all fall within the protection scope of this utility model.

Claims

1. A flame sensing circuit, characterized in that, Applied to gas combustion equipment with a controller; The flame sensing circuit includes: Flame detection electrode, used to receive flame ionization signals; Analog-to-digital conversion circuit (1) and analog signal detection circuit (2); The input terminal of the analog-to-digital converter circuit (1) is connected to the flame detection electrode, and the output terminal is connected to the digital signal receiving port of the controller to output a high level or a low level to the controller. The input terminal of the analog signal detection circuit (2) is connected to the flame detection electrode, and the output terminal is connected to the analog signal receiving port of the controller.

2. The circuit according to claim 1, characterized in that, The analog-to-digital conversion circuit (1) includes: a signal determination unit (11), the signal determination unit (11) including a DC power supply and a first resistor; One end of the first resistor is connected to the DC power supply, and the other end is connected to the flame detection electrode.

3. The circuit according to claim 2, characterized in that, The signal determination unit (11) further includes a second resistor and a first capacitor; Wherein, one end of the second resistor is connected to one end of the first resistor, one end of the first capacitor and the flame detection electrode, and the other end is connected to the digital signal receiving port of the controller; The other end of the first capacitor is grounded.

4. The circuit according to claim 2, characterized in that, The analog-to-digital conversion circuit (1) further includes a voltage clamping unit (12), which includes a first diode and a second diode; Wherein, the first end of the first diode is connected to the DC power supply, and the second end is connected to both the other end of the first resistor and the first end of the second diode; The other end of the second diode is grounded.

5. The circuit according to claim 2, characterized in that, The analog-to-digital converter circuit (1) further includes a third resistor and a fourth resistor; Wherein, one end of the third resistor is connected to the other end of the first resistor and one end of the fourth resistor, and the other end is connected to the flame detection electrode; The other end of the fourth resistor is grounded.

6. The circuit according to claim 2, characterized in that, The circuit also includes an AC power supply circuit (3), which includes an AC power source and a second capacitor; the analog-to-digital conversion circuit also includes a fifth resistor; Wherein, one end of the fifth resistor is connected to the other end of the first resistor and one end of the second capacitor, and the other end is connected to the flame detection electrode; The other end of the second capacitor is connected to one end of the AC power supply; The other end of the AC power supply is grounded.

7. The circuit according to claim 1, characterized in that, The analog signal detection circuit (2) includes an operational amplifier, a sixth resistor, and a seventh resistor; The operational amplifier has its first input terminal connected to one end of the sixth resistor and the other end of the seventh resistor, its second input terminal grounded, and its output terminal connected to the other end of the seventh resistor and the analog signal receiving port of the controller. The other end of the sixth resistor is connected to the flame detection electrode.

8. The circuit according to claim 7, characterized in that, The analog signal detection circuit (2) further includes an eighth resistor and a third capacitor; One end of the eighth resistor is connected to the other end of the sixth resistor and one end of the third capacitor, and the other end is connected to the flame detector. The other end of the third capacitor is connected to the second input terminal of the operational amplifier and grounded.

9. The circuit according to claim 7, characterized in that, The circuit also includes an AC power supply circuit (3), which includes an AC power source and a fourth capacitor; the analog signal detection circuit (2) also includes a ninth resistor; One end of the ninth resistor is connected to the other end of the sixth resistor and one end of the fourth capacitor, and the other end is connected to the flame detection electrode. The other end of the fourth capacitor is connected to one end of the AC power supply.

10. A gas combustion device, characterized in that, It includes the flame sensing circuit, controller, and gas proportional valve as described in any one of claims 1-9; the digital signal receiving port of the controller is electrically connected to the output terminal of the analog-to-digital conversion circuit (1), the analog signal receiving port of the controller is electrically connected to the output terminal of the analog signal detection circuit (2), and the control terminal of the controller is electrically connected to the gas proportional valve.

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