Control circuit for a fuel-fired heating appliance and fuel-fired heating appliance

Abstract

The utility model relates to a heating equipment technical field discloses a control circuit and fuel heating equipment of fuel heating equipment, the first contact of relay in the utility model is connected with the first end of alternating -current source, and the motor and igniter of fuel heating equipment are all connected with the second contact, relay control circuit includes thyristor, resistance unit, the first end of thyristor is connected with the first end of relay control coil and one end of resistance unit, and the second end of thyristor is connected with the second end of control coil and the other end of resistance unit. Thus, the resistance unit control thyristor's on-off is adopted to the combustion state of fuel heating device and is detected to control the on-off of relay, and the working of fuel heating equipment's motor and igniter is further controlled, thereby not needing to connect the sudden jump temperature controller in the main power supply fire line loop, can realize the combustion protection of fuel heating equipment to reduce the cost of the combustion protection of fuel heating device, and the reliability is high.

Description

Technical Field

[0001] This utility model relates to the field of heating equipment technology, and in particular to a control circuit and a fuel-fired heating device. Background Technology

[0002] To ensure the safe use of gas-fired heating appliances, the combustion status is typically monitored and protected. In cases of abnormal combustion, such as overheating, the power circuit is cut off to ensure combustion safety. In related technologies, combustion protection devices are usually connected in series in the main power supply circuit to cut off the power supply in case of an anomaly. However, the selection of protection device parameters in this method is affected by the load power; the higher the load power, the higher the rated current of the protection device required, leading to increased costs. Therefore, a control circuit is needed to reduce the cost requirements for combustion protection in fuel-fired heaters. Utility Model Content

[0003] The first technical problem solved by this utility model is to provide a control circuit for a fuel-fired heating device, which effectively solves the problem of high combustion protection costs for fuel-fired heaters.

[0004] The second technical problem solved by this utility model is to provide a fuel-fired heating device that effectively solves the problem of high combustion protection costs for fuel-fired heaters.

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

[0006] A control circuit for a fuel-fired heating device includes a DC power supply circuit, a relay, and a relay control circuit.

[0007] The first input terminal of the DC power supply circuit is connected to the first terminal of the AC power supply, and the second input terminal of the DC power supply circuit is connected to the second terminal of the AC power supply. The DC power supply circuit provides DC power to the relay and the relay control circuit.

[0008] The first contact of the relay is connected to the first terminal of the AC power supply, and the second contact is connected to both the motor and the igniter of the fuel-fired heating device; the motor and the igniter are both connected to the second terminal of the AC power supply.

[0009] The relay control circuit includes a thyristor and a resistor unit, which is used to detect the combustion status of the fuel heating equipment.

[0010] The first end of the thyristor is connected to the first end of the control coil of the relay and one end of the resistor unit, and the second end of the thyristor is connected to the second end of the control coil and the other end of the resistor unit.

[0011] Compared with the prior art, the control circuit of the fuel-fired heating device of this utility model has the following advantages: it uses a resistor unit to control the on / off state of the thyristor, thereby controlling the on / off state of the relay, and then controlling the operation of the motor and igniter of the fuel-fired heating device; at the same time, the resistor unit detects the combustion state of the fuel-fired heater, and the circuit state of the resistor unit can change with the combustion state of the fuel-fired heater, thereby controlling the on / off state of the thyristor. Therefore, it is not necessary to connect the snap-on thermostat in series with the main power supply live wire circuit to achieve combustion protection of the fuel-fired heating device, thereby reducing the cost of combustion protection of the fuel-fired heater and ensuring high reliability.

[0012] In one embodiment, the resistive unit includes a photosensitive sensor and a snap-on temperature controller;

[0013] One end of the photosensitive sensor is connected to the first end of the silicon controlled rectifier, and the other end is connected to one end of the snap-on temperature controller.

[0014] The other end of the snap-on temperature controller is connected to the second end of the SCR.

[0015] In one embodiment, the relay control circuit further includes a first resistor;

[0016] One end of the first resistor is connected to the DC power supply circuit, and the other end is connected to one end of the resistor unit.

[0017] In one embodiment, the relay control circuit further includes a first Zener diode, a second resistor, and a third resistor;

[0018] One end of the second resistor is connected to one end of the resistor unit, and the other end is connected to the negative terminal of the first Zener diode.

[0019] The positive terminal of the first Zener diode is connected to the third terminal of the thyristor and one end of the third resistor;

[0020] The other end of the third resistor is connected to the second end of the thyristor.

[0021] In one embodiment, the relay control circuit further includes a first diode;

[0022] The positive terminal of the first diode is connected to one end of the resistor unit, and the negative terminal is connected to the first end of the thyristor.

[0023] In one embodiment, the circuit further includes a delay control circuit;

[0024] The delay control circuit includes a first transistor, a first capacitor, a second capacitor, and a fourth resistor;

[0025] In this configuration, the first terminal of the first transistor is connected to one end of the first capacitor and one end of the fourth resistor, the second terminal is connected to one end of the resistor unit, and the third terminal is connected to the other end of the first capacitor.

[0026] The other end of the fourth resistor is connected to one end of the second capacitor;

[0027] The other end of the second capacitor is connected to the DC power supply circuit.

[0028] In one embodiment, the delay control circuit further includes a fifth resistor and a second diode;

[0029] In this configuration, one end of the fifth resistor is connected to the other end of the fourth resistor, one end of the second capacitor, and the positive terminal of the second diode, while the other end is connected to the other end of the first capacitor and the negative terminal of the second diode.

[0030] In one embodiment, the DC power supply circuit includes a first power supply unit;

[0031] The first power supply unit includes a third diode, a third capacitor, a sixth resistor, and a seventh resistor;

[0032] The first terminal of the AC power supply is connected to the positive terminal of the third diode, and the second terminal is connected to one end of the third capacitor.

[0033] The negative terminal of the third diode is connected to one end of the third capacitor and one end of the sixth resistor;

[0034] The other end of the sixth resistor is connected to one end of the seventh resistor;

[0035] The other end of the seventh resistor is connected to both the first end of the control coil and the first end of the thyristor.

[0036] In one embodiment, the DC power supply circuit includes a second power supply unit;

[0037] The second power supply unit includes an eighth resistor, a fourth diode, a fourth capacitor, and a second Zener diode;

[0038] Among them, one end of the eighth resistor is connected to the negative terminal of the third diode, and the other end is connected to the positive terminal of the fourth diode, one end of the resistor unit, one end of the fourth capacitor, and the negative terminal of the second Zener diode.

[0039] The cathode of the fourth diode is connected to both the first terminal of the control coil and the first terminal of the thyristor.

[0040] The other end of the fourth capacitor is connected to the positive terminal of the second Zener diode and the second terminal of the AC power supply.

[0041] The second technical problem mentioned above is solved by the following technical solution:

[0042] A fuel-fired heating device includes a control circuit for a fuel-fired heating device as described in any of the above embodiments. Attached Figure Description

[0043] 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.

[0044] Figure 1 This is a schematic diagram of the control circuit of a fuel-fired heating device according to an embodiment of the present invention;

[0045] Figure 2 This is a circuit diagram of the control circuit of a fuel-fired heating device according to an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram of the working process of the control circuit of a fuel-fired heating device according to an embodiment of the present invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1. DC power supply circuit; 11. First power supply unit; 12. Second power supply unit; 2. Relay control circuit; 21. Resistor unit. Detailed Implementation

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] To ensure the safe use of gas-fired heating appliances, the combustion status is typically monitored and protected. In cases of abnormal combustion, such as overheating, the power circuit is cut off to ensure combustion safety. In related technologies, combustion protection devices are usually connected in series in the main power supply circuit to cut off the power supply in case of an anomaly. However, the selection of protection device parameters in this method is affected by the load power; the higher the load power, the higher the rated current of the protection device required, leading to increased costs. Therefore, a control circuit is needed to reduce the cost requirements for combustion protection in fuel-fired heaters.

[0054] Specifically, protection of the combustion status of gas-fired appliances includes over-temperature protection and flameout protection. One common technology uses a snap-on thermostat for over-temperature protection, connected in series with the main power supply's live wire circuit. When the temperature exceeds a certain level, the snap-on thermostat disconnects and switches the power circuit. However, this solution is costly because the rated current of the snap-on thermostat is significantly affected by the load power. Another common technology uses thermocouples for flameout protection, controlling the gas supply by engaging a solenoid valve. However, this solution is only suitable for gas-fired appliances and not for fuel-fired appliances.

[0055] Based on this, the present invention provides a control circuit for a fuel-fired heating device, including a DC power supply circuit, a relay, and a relay control circuit; wherein, the first input terminal of the DC power supply circuit is connected to the first terminal of the AC power supply, and the second input terminal of the DC power supply circuit is connected to the second terminal of the AC power supply, and the DC power supply circuit provides DC power to the relay and the relay control circuit; the first contact of the relay is connected to the first terminal of the AC power supply, and the second contact is connected to both the motor and the igniter of the fuel-fired heating device; both the motor and the igniter are connected to the second terminal of the AC power supply; the relay control circuit includes a thyristor and a resistor unit, the resistor unit being used to detect the combustion state of the fuel-fired heating device; wherein, the first terminal of the thyristor is connected to both the first terminal of the control coil of the relay and one terminal of the resistor unit, and the second terminal of the thyristor is connected to both the second terminal of the control coil and the other terminal of the resistor unit. This invention uses a resistor unit to control the on / off state of a thyristor, thereby controlling the on / off state of a relay, and ultimately controlling the operation of the motor and igniter of the fuel-fired heating device. Simultaneously, the resistor unit detects the combustion state of the fuel-fired heater, and its circuit state changes in accordance with the combustion state, thus controlling the on / off state of the thyristor. Therefore, it eliminates the need to connect a snap-action thermostat in series with the main power supply live wire circuit, achieving combustion protection for the fuel-fired heating device, thereby reducing the cost of combustion protection for fuel-fired heaters and ensuring high reliability.

[0056] The following is combined Figures 1 to 3 The following describes embodiments of the present invention.

[0057] According to an embodiment of the present invention, a control circuit for a fuel-fired heating device is provided, which can be applied to various types of fuel-fired heating devices. Figure 1 This is a schematic diagram of the control circuit of a fuel-fired heating device according to an embodiment of this utility model, as shown below. Figure 1 As shown, the control circuit of the fuel-fired heating device includes a DC power supply circuit 1, a relay K1, and a relay control circuit 2.

[0058] The DC power supply circuit 1 has its first input terminal connected to the first terminal of the AC power supply, and its second input terminal connected to the second terminal of the AC power supply. The DC power supply circuit 1 provides DC power to the relay K1 and the relay control circuit 2. The first terminal of the AC power supply corresponds to the ACL live wire, and the second terminal of the AC power supply corresponds to the CAN neutral wire. The relay K1 and the relay control circuit 2 are connected to the DC power supply circuit 1, and obtain DC power from the DC power supply circuit 1 on the one hand, and are grounded through the DC power supply circuit 1 on the other hand.

[0059] The first contact of relay K1 is connected to the first terminal of the AC power supply, and the second contact is connected to both the motor and the igniter of the fuel-fired heating device; both the motor and the igniter are connected to the second terminal of the AC power supply. The operation of the motor and the igniter is controlled by switching the first and second contacts of relay K1 on and off.

[0060] The relay control circuit 2 includes a silicon controlled rectifier (SCR) VS1 and a resistor unit 21. The resistor unit 21 is used to detect the combustion status of the fuel-fired heating device. The first terminal of the SCR VS1 is connected to both the first terminal of the control coil of the relay K1 and one terminal of the resistor unit 21. The second terminal of the SCR VS1 is connected to both the second terminal of the control coil and the other terminal of the resistor unit 21. The resistance value of the resistor unit 21 changes according to the combustion status of the fuel-fired heating device, thereby controlling the on / off state of the SCR VS1. When the SCR VS1 is on, a current is generated in the circuit containing the SCR VS1, which divides the voltage of the control coil of the relay K1, causing a decrease in the electromagnetic intensity generated on the control coil of the relay K1. This creates an open circuit between the first and second contacts, stopping the motor and igniter from working. When the SCR VS1 is off, there is no circuit in the circuit containing the SCR VS1. The electromagnetic intensity generated on the control coil of the relay K1 is sufficient to maintain a circuit between the first and second contacts, allowing the motor and igniter to connect to the power supply and operate normally. Therefore, by detecting the combustion status of the fuel heating device through the resistor unit 21, combustion protection of the fuel heating device can be achieved; furthermore, since the resistor unit 21 is separated from the main circuit, the device parameters of the resistor unit 21 are not affected by the load power, which can effectively reduce costs.

[0061] In one embodiment, Figure 2 This is a circuit diagram of the control circuit of a fuel-fired heating device according to an embodiment of this utility model, as shown below. Figure 2 As shown, the resistor unit 21 includes a photosensitive sensor and a snap-on thermostat; the photosensitive sensor detects the flame intensity of the combustion flame of the fuel-fired heating device, and the snap-on thermostat detects the combustion temperature of the fuel-fired heating device. One end of the photosensitive sensor is connected to the first terminal of the silicon controlled rectifier (SCR) VS1, and the other end is connected to one end of the snap-on thermostat; the other end of the snap-on thermostat is connected to the second terminal of the SCR VS1.

[0062] In one embodiment, such as Figure 2As shown, the relay control circuit 2 also includes a first resistor R1; one end of the first resistor R1 is connected to the DC power supply circuit 1, and the other end is connected to one end of the resistor unit 21. The first resistor R1 and the resistor unit 21 form a voltage divider circuit, which controls the on / off state of the thyristor VS1 through the voltage division of the resistor unit 21. When the fuel heater is burning normally, the snap-on thermostat is turned on, and the resistance value of the photosensitive sensor decreases as the flame intensifies. At this time, the resistance value of the resistor unit 21 is small, and the voltage obtained by voltage division is less than the voltage threshold that can trigger the thyristor VS1 to turn on. At this time, the thyristor VS1 is turned off, the relay K1 is turned on, and the control coil controls the formation of a circuit between the first contact and the second contact, controlling the operation of the motor and the igniter. When the combustion temperature of the fuel heater exceeds the safe temperature, the snap-on thermostat is turned off. At this time, the resistor unit 21 is equivalent to being in a high resistance state, and the resistor unit 21... When the voltage drop across resistor 1 exceeds the voltage threshold, the thyristor VS1 conducts, relay K1 disconnects, and the control coil of relay K1 controls the first and second contacts to form an open circuit, thus stopping the motor of the fuel-fired heating device and turning off the igniter. When the fuel-fired heater is turned off, the resistance of the photosensitive sensor increases, and the voltage drop across resistor 21 exceeds the voltage threshold. At this time, the thyristor VS1 conducts, relay K1 disconnects, and the control coil of relay K1 controls the first and second contacts to form an open circuit, thus stopping the motor of the fuel-fired heating device and turning off the igniter.

[0063] In one embodiment, such as Figure 2 As shown, the relay control circuit 2 also includes a first Zener diode Z1, a second resistor R2, and a third resistor R3; wherein, one end of the second resistor R2 is connected to one end of the resistor unit 21, and the other end is connected to the negative terminal of the first Zener diode Z1; the positive terminal of the first Zener diode Z1 is connected to the third terminal of the thyristor VS1 and one end of the third resistor R3; the other end of the third resistor R3 is connected to the second terminal of the thyristor VS1.

[0064] In one embodiment, the first terminal of the thyristor VS1 corresponds to the anode of the thyristor VS1, the second terminal corresponds to the cathode of the thyristor VS1, and the third terminal corresponds to the control stage of the thyristor VS1. When the voltage divided by the resistor unit 21 exceeds the voltage regulated by the first Zener diode Z1, the first Zener diode Z1 conducts, supplying power to the third terminal of the thyristor VS1, and the thyristor VS1 conducts. After the thyristor VS1 conducts, as long as the voltage between the first and second terminals of the thyristor VS1 is maintained, the thyristor VS1 will continue to conduct.

[0065] In one embodiment, the DC voltage obtained from the DC power supply circuit 1 in the circuit containing resistor unit 21 and first resistor R1 is 10V, the resistance value of first resistor R1 is 30kΩ, the light resistance of the photosensitive sensor in resistor unit 21 is less than 10kΩ and the dark resistance is greater than 30kΩ, and the voltage regulation voltage of first Zener diode Z1 is 5V.

[0066] In one embodiment, the relay control circuit 2 further includes a first diode D1, which enables unidirectional conduction of the circuit; the positive terminal of the first diode D1 is connected to one end of the resistor unit 21, and the negative terminal is connected to the first end of the thyristor VS1.

[0067] In one embodiment, such as Figure 2 As shown, the circuit also includes a delay control circuit 3. The delay control circuit 3 is used to keep the thyristor VS1 off for a period of time when the AC power is first connected, that is, when the fuel-fired heating device is first powered on, to provide sufficient start-up time for the fuel-fired heating device and ensure its start-up stability. The delay control circuit 3 includes a first transistor Q1, a first capacitor C1, a second capacitor C2, and a fourth resistor R4. Specifically, the first terminal of the first transistor Q1 is connected to one end of the first capacitor C1 and one end of the fourth resistor R4; the second terminal is connected to one end of the resistor unit 21; and the third terminal is connected to the other end of the first capacitor C1. The other end of the fourth resistor R4 is connected to one end of the second capacitor C2; and the other end of the second capacitor C2 is connected to the DC power supply circuit 1.

[0068] In one embodiment, the first terminal of the first transistor Q1 corresponds to the base of the transistor, the second terminal of the first transistor Q1 corresponds to the collector of the transistor, and the third terminal of the first transistor Q1 corresponds to the emitter of the transistor. At the instant the fuel-fired heating device is powered on, a pulse current is generated across the first capacitor C1, the second capacitor C2, and the fourth resistor R4, causing the first capacitor C1 to charge. The base voltage of the first transistor Q1 reaches the turn-on voltage of 0.58V, thereby pulling the potential at the connection point between the resistor unit 21 and the first resistor R1 down to 0V, thus turning off the thyristor VS1.

[0069] In one embodiment, such as Figure 2 As shown, the delay control circuit 3 also includes a fifth resistor R5 and a second diode D2. One end of the fifth resistor R5 is connected to the other end of the fourth resistor R4, one end of the second capacitor C2, and the positive terminal of the second diode D2. The other end is connected to the other end of the first capacitor C1 and the negative terminal of the second diode D2. After the fuel-fired heating device is powered on, the first capacitor C1 gradually discharges through the circuit of the fourth resistor R4 and the fifth resistor R5. After a period of time, the voltage across the first capacitor C1 drops below 0.5V, and the first transistor Q1 is turned off. At this time, the on / off state of the thyristor VS1 is determined by the voltage division of the resistor unit 21, thereby achieving combustion protection for the fuel-fired heating device.

[0070] In one embodiment, such as Figure 2As shown, the DC power supply circuit 1 includes a first power supply unit 11, which provides DC power to the relay K1. The first power supply unit 11 includes a third diode D3, a third capacitor C3, a sixth resistor R6, and a seventh resistor R7; wherein, the first terminal of the AC power supply is connected to the positive terminal of the third diode D3, and the second terminal is connected to one end of the third capacitor C3; the negative terminal of the third diode D3 is connected to one end of the third capacitor C3 and one end of the sixth resistor R6; the other end of the sixth resistor R6 is connected to one end of the seventh resistor R7; and the other end of the seventh resistor R7 is connected to the first terminal of the control coil and the first terminal of the thyristor VS1.

[0071] Specifically, the 220V AC power supply is rectified into 120V DC voltage by the third diode D3. This DC voltage is then divided by the sixth resistor R6, the seventh resistor R7, and the internal resistance of relay K1 to provide a 48V operating voltage to relay K1. The resistance values ​​of the sixth resistor R6 and the seventh resistor R7 are both 3.3kΩ, and the internal resistance of relay K1 is 4.5kΩ.

[0072] In one embodiment, such as Figure 2 As shown, the DC power supply circuit 1 includes a second power supply unit 12, which provides DC power to the relay control circuit 2. The second power supply unit 12 includes an eighth resistor R8, a fourth diode D4, a fourth capacitor C4, and a second Zener diode Z2. The 120V rectified by the first power supply unit 11 is clamped and regulated to 10V by the second Zener diode Z2. One end of the eighth resistor R8 is connected to the cathode of the third diode D3, and the other end is connected to the anode of the fourth diode D4, one end of the resistor unit 21, one end of the fourth capacitor C4, and the cathode of the second Zener diode Z2. The cathode of the fourth diode D4 is connected to the first terminal of the control coil and the first terminal of the thyristor VS1. The other end of the fourth capacitor C4 is connected to the anode of the second Zener diode Z2 and the second terminal of the AC power supply.

[0073] In one embodiment, such as Figure 2 As shown, the relay control circuit 2 also includes a fifth capacitor C5, which serves as a bypass filter capacitor to prevent the thyristor VS1 from being mis-energized due to current fluctuations. One end of the fifth capacitor C5 is connected to the positive terminal of the first Zener diode Z1 and one end of the third resistor R3, while the other end is connected to the other end of the third resistor R3.

[0074] In one embodiment, such as Figure 2 As shown, resistor unit 21 also includes a sixth capacitor C6, which serves as a bypass filter capacitor to stabilize the voltage across resistor unit 21 and prevent mis-conduction by the silicon controlled rectifier VS1. One end of the sixth capacitor C6 is connected to one end of the photosensitive sensor, and the other end is connected to the other end of the snap-on temperature controller.

[0075] In one embodiment, such as Figure 2 As shown, the first power supply unit 11 also includes a circuit fuse F1, which is used to provide overload protection for the circuit. One end of the circuit fuse F1 is connected to the second terminal of the AC power supply, and the other end is connected to one end of the third capacitor C3.

[0076] In a specific embodiment, such as Figure 3 As shown, the operation and control flow of the control circuit of the fuel-fired heating device provided by this utility model are as follows:

[0077] Step S301: Detect and determine the combustion status of the fuel heating device collected by the resistance unit 21.

[0078] In this embodiment, the resistance value of the resistor unit 21 changes with the combustion state of the fuel heating device, so the combustion state of the fuel heating device can be determined based on the resistance value of the resistor unit 21.

[0079] In one embodiment, the resistor unit 21 includes a photosensitive sensor for flame intensity detection and a snap-on thermostat for over-temperature detection. Simultaneously, the resistor unit 21 and the first resistor R1 form a voltage divider circuit. Correspondingly, detecting and determining the combustion state of the fuel-fired heating device collected by the resistor unit includes: detecting the flame signal collected by the photosensitive sensor in the resistor unit 21 and the temperature control state of the snap-on thermostat; if the flame signal is below a set threshold or the temperature control state is open, the combustion state indicates that the fuel-fired heating device is in an over-temperature state or a flameout state; if the flame signal reaches the set threshold and the temperature control state is closed, the combustion state indicates that the fuel-fired heating device meets the combustion conditions.

[0080] The resistance of the photosensitive sensor decreases as the combustion flame intensifies. When the fuel-fired heating device is in an off-state, the resistance reaches its maximum value. When the flame signal is below a set threshold, the resistance of the photosensitive sensor becomes too high, causing the voltage division of resistor unit 21 to exceed the voltage threshold required to trigger the conduction of the silicon controlled rectifier (SCR) VS1. When the combustion temperature of the fuel-fired heater exceeds the safe temperature, the thermostat trips, and the temperature control is in an off state. At this time, resistor unit 21 is essentially in a high-resistance state, and the voltage division of resistor unit 21 exceeds the voltage threshold. In other words, when the flame signal is below the set threshold or the temperature control is in an off state, the voltage division of resistor unit 21 exceeds the voltage threshold, indicating that the fuel-fired heating device is either overheating or off-state. Conversely, when the fuel-fired heater is burning normally, the thermostat trips, and the temperature control is in a closed state. The resistance of the photosensitive sensor decreases as the combustion flame intensifies. When the flame signal reaches the set threshold, the resistance of resistor unit 21 is low, and the voltage division is less than the voltage threshold, indicating that the fuel-fired heating device is ready for combustion.

[0081] In step S302, when the combustion status indicates that the fuel heating device has combustion conditions, the thyristor VS1 is turned off, the relay K1 is turned on, and the control coil controls the formation of a circuit between the first contact and the second contact to control the operation of the motor and the igniter.

[0082] In this embodiment, when the combustion state indicates that the fuel heating device has combustion conditions, the voltage obtained by the voltage division of the resistor unit 21 is less than the voltage threshold. At this time, the thyristor VS1 is turned off, the relay K1 is turned on, and the control coil controls the formation of a circuit between the first contact and the second contact, controlling the operation of the motor and the igniter.

[0083] In one embodiment, when the combustion state indicates that the fuel-fired heating device is in an overheated state or a flameout state, the voltage obtained by the voltage division of the resistor unit 21 exceeds the voltage threshold. At this time, the thyristor VS1 is turned on, the relay K1 is turned off, and the control coil controls the first contact and the second contact to form an open circuit, thereby controlling the motor of the fuel-fired heating device to stop working and the igniter to turn off.

[0084] In one embodiment, to provide sufficient start-up time when the fuel-fired heating device is first turned on and to ensure the stability of the device's start-up, the method further includes a control method for the delay control circuit 3, specifically as follows: In response to the fuel-fired heating device being powered on, the charging and discharging state of the first capacitor C1 is detected; when the charging and discharging state is when it is charged to a first preset voltage, the first transistor Q1 is turned on, the thyristor VS1 is turned off, and the relay K1 is closed to control the motor and igniter of the fuel-fired heating device to operate. When the charging and discharging state is when it is discharged to a second preset voltage, the first transistor Q1 is turned off, and the combustion state of the fuel-fired heating device collected by the resistor unit 21 is detected and determined, so as to control the operation of the fuel-fired heating device based on the detection of the combustion state by the resistor unit 21. The first preset voltage is the base conduction voltage of the first transistor Q1, which can be 0.58V, and the second preset voltage is the maximum base voltage when the first transistor Q1 is turned off, which can be 0.5V.

[0085] The control circuit of the fuel-fired heating device provided by this utility model uses a resistor unit to control the on / off state of the thyristor, thereby controlling the on / off state of the relay, and in turn controlling the operation of the motor and igniter of the fuel-fired heating device. At the same time, the resistor unit detects the combustion state of the fuel-fired heater, and the circuit state of the resistor unit can change with the combustion state of the fuel-fired heater, thereby controlling the on / off state of the thyristor. Therefore, it is not necessary to connect the snap-on thermostat in series with the main power supply live wire circuit to achieve combustion protection of the fuel-fired heating device, thereby reducing the cost of combustion protection of the fuel-fired heater and ensuring high reliability.

[0086] According to an embodiment of the present invention, another aspect provides a fuel-fired heating device, including a control circuit for a fuel-fired heating device as described in any of the above embodiments.

[0087] 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.

[0088] 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 control circuit for a fuel-fired heating device, characterized in that, Includes a DC power supply circuit (1), a relay, and a relay control circuit (2); Wherein, the first input terminal of the DC power supply circuit (1) is connected to the first terminal of the AC power supply, the second input terminal of the DC power supply circuit (1) is connected to the second terminal of the AC power supply, and the DC power supply circuit (1) provides DC power to the relay and the relay control circuit (2); The first contact of the relay is connected to the first terminal of the AC power supply, and the second contact is connected to both the motor and the igniter of the fuel-fired heating device; the motor and the igniter are both connected to the second terminal of the AC power supply. The relay control circuit (2) includes a thyristor and a resistor unit (21), the resistor unit (21) being used to detect the combustion status of the fuel heating device; The first end of the thyristor is connected to the first end of the control coil of the relay and one end of the resistor unit (21), and the second end of the thyristor is connected to the second end of the control coil and the other end of the resistor unit (21).

2. The circuit according to claim 1, characterized in that, The resistor unit (21) includes a photosensitive sensor and a sudden temperature controller; Wherein, one end of the photosensitive sensor is connected to the first end of the thyristor, and the other end is connected to one end of the snap-on temperature controller; The other end of the snap-on temperature controller is connected to the second end of the thyristor.

3. The circuit according to claim 1, characterized in that, The relay control circuit (2) also includes a first resistor; One end of the first resistor is connected to the DC power supply circuit (1), and the other end is connected to one end of the resistor unit (21).

4. The circuit according to claim 1, characterized in that, The relay control circuit (2) also includes a first Zener diode, a second resistor, and a third resistor; Wherein, one end of the second resistor is connected to one end of the resistor unit (21), and the other end is connected to the negative terminal of the first Zener diode; The positive terminal of the first Zener diode is connected to the third terminal of the thyristor and one end of the third resistor; The other end of the third resistor is connected to the second end of the thyristor.

5. The circuit according to claim 1, characterized in that, The relay control circuit (2) also includes a first diode; The positive terminal of the first diode is connected to one end of the resistor unit (21), and the negative terminal is connected to the first end of the thyristor.

6. The circuit according to claim 1, characterized in that, The circuit also includes a delay control circuit (3); The delay control circuit (3) includes a first transistor, a first capacitor, a second capacitor, and a fourth resistor; Wherein, the first end of the first transistor is connected to one end of the first capacitor and one end of the fourth resistor, the second end is connected to one end of the resistor unit (21), and the third end is connected to the other end of the first capacitor; The other end of the fourth resistor is connected to one end of the second capacitor; The other end of the second capacitor is connected to the DC power supply circuit (1).

7. The circuit according to claim 6, characterized in that, The delay control circuit (3) also includes a fifth resistor and a second diode; One end of the fifth resistor is connected to the other end of the fourth resistor, one end of the second capacitor, and the positive terminal of the second diode, while the other end is connected to the other end of the first capacitor and the negative terminal of the second diode.

8. The circuit according to claim 1, characterized in that, The DC power supply circuit (1) includes a first power supply unit (11); The first power supply unit (11) includes a third diode, a third capacitor, a sixth resistor, and a seventh resistor; Wherein, the first end of the AC power supply is connected to the positive terminal of the third diode, and the second end is connected to one end of the third capacitor; The negative terminal of the third diode is connected to one end of the third capacitor and one end of the sixth resistor; The other end of the sixth resistor is connected to one end of the seventh resistor; The other end of the seventh resistor is connected to both the first end of the control coil and the first end of the thyristor.

9. The circuit according to claim 8, characterized in that, The DC power supply circuit (1) includes a second power supply unit (12); The second power supply unit (12) includes an eighth resistor, a fourth diode, a fourth capacitor, and a second Zener diode; Among them, one end of the eighth resistor is connected to the negative terminal of the third diode, and the other end is connected to the positive terminal of the fourth diode, one end of the resistor unit (21), one end of the fourth capacitor, and the negative terminal of the second Zener diode. The negative terminal of the fourth diode is connected to both the first terminal of the control coil and the first terminal of the thyristor. The other end of the fourth capacitor is connected to the positive terminal of the second Zener diode and the second terminal of the AC power supply.

10. A fuel-fired heating device, characterized in that, Includes the control circuit of the fuel-fired heating device according to any one of claims 1-9.

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