Butterfly valve detection circuit, detection device and heating system

Abstract

The embodiment of the application discloses a butterfly valve detection circuit, a detection device and a heating and ventilation system. The detection circuit comprises a feedback circuit and at least one detection branch. When the butterfly valve is in a fully open position or a fully closed position, the feedback circuit is triggered to output alternating current with a first preset voltage. The detection branch comprises a rectifier circuit and an isolation circuit. The rectifier circuit is connected with the feedback circuit and is used for connecting the alternating current and rectifying the rectifier circuit into direct current. The high-voltage side of the isolation circuit is connected with the rectifier circuit to connect the direct current. The low-voltage side of the isolation circuit is used for outputting a detection voltage to isolate the direct current of the high-voltage side from the detection voltage of the low-voltage side. The safety performance of the detection circuit as a whole can be improved, the cost of the low-voltage side components can be reduced, the cost of the detection circuit as a whole can be reduced, the safety performance of the detection circuit as a whole can be improved, the position of the butterfly plate can be judged according to the detection voltage, and the accuracy and convenience of obtaining the position of the butterfly plate can be improved.

Description

Technical Field

[0001] This application relates to the field of valve equipment technology, and more specifically, to a detection circuit, detection device, and HVAC system for a butterfly valve. Background Technology

[0002] In the relevant technical field, HVAC systems typically use refrigerant transmission pipelines as carriers for carrying and transporting heat exchange media. In order to facilitate the control of the movement of heat exchange media in the refrigerant transmission pipelines, butterfly valves are often connected to the refrigerant transmission pipelines. However, since the refrigerant transmission pipelines are in a closed state, it is not easy to determine the position of the butterfly valve, which can easily cause inconvenience to the operators. Utility Model Content

[0003] This application provides a detection circuit for a butterfly valve, which aims to determine the position of the butterfly plate based on the detection voltage, thereby improving the accuracy and convenience of obtaining the butterfly plate position.

[0004] This application provides a detection circuit for a butterfly valve. The detection circuit includes a feedback circuit and at least one detection branch. When the butterfly valve is in the fully open or fully closed position, the feedback circuit is triggered to output AC power with a first preset voltage. The detection branch includes a rectifier circuit and an isolation circuit. The rectifier circuit is connected to the feedback circuit and is used to connect AC power and rectify the AC power into DC power. The high-voltage side of the isolation circuit is connected to the rectifier circuit to connect DC power, and the low-voltage side of the isolation circuit is used to output a detection voltage to isolate the DC power on the high-voltage side from the detection voltage on the low-voltage side.

[0005] Based on the above embodiments, the electrical isolation between high-voltage and low-voltage electricity achieved through the isolation circuit improves the overall safety performance of the detection circuit. Furthermore, the electrical isolation between the high-voltage and low-voltage sides reduces the withstand voltage of the low-voltage side components, thereby lowering their cost and ultimately reducing the overall cost of the detection circuit while still enhancing its safety performance. Additionally, the position of the butterfly plate can be determined based on the detected voltage, improving the accuracy and convenience of obtaining the butterfly plate's location.

[0006] In some embodiments, the rectifier circuit includes a full-bridge rectifier circuit or a half-bridge rectifier circuit; the isolation circuit includes one of an optocoupler, a relay, and a solid-state relay. In some embodiments, the rectifier circuit includes a full-bridge rectifier circuit, the two input terminals of which are used to connect to AC power; the isolation circuit includes an optocoupler, the high-voltage side input terminal and output terminal of which are respectively connected to the two output terminals of the full-bridge rectifier circuit, and the low-voltage side input terminal and output terminal of which are respectively used to output a detection voltage and ground.

[0007] In some embodiments, the detection branch further includes a current limiting circuit connected in series between the feedback circuit and the full-bridge rectifier circuit to limit the current flowing through the full-bridge rectifier circuit; or, the current limiting circuit is connected in series between the full-bridge rectifier circuit and the high-voltage side to limit the current flowing through the high-voltage side.

[0008] Based on the above embodiments, the current flowing through the full-bridge rectifier circuit is limited by the current limiting circuit, thereby reducing the current carried by the full-bridge rectifier circuit, which in turn reduces the cost and size of the full-bridge rectifier circuit, thereby reducing the overall cost and size of the detection branch and improving the convenience of use, installation and transportation of the butterfly valve detection device.

[0009] Understandably, the current limiting circuit can also be connected in series between the full-bridge rectifier circuit and the high-voltage side to limit the current flowing through the high-voltage side, thus enabling the optocoupler to have a longer service life.

[0010] In some embodiments, the current limiting circuit includes a first current limiting resistor connected in series between the output of the feedback circuit and the input of the full-bridge rectifier circuit, or the first current limiting resistor connected in series between the output of the full-bridge rectifier circuit and the input of the high-voltage side.

[0011] Based on the above embodiments, the current flowing through the full-bridge rectifier circuit is limited by the first current-limiting resistor, thereby reducing the current carried by the full-bridge rectifier circuit, which in turn reduces the cost and size of the full-bridge rectifier circuit, thereby reducing the overall cost and size of the detection branch and improving the overall convenience of use, installation and transportation of the butterfly valve detection device.

[0012] Understandably, the first current-limiting resistor can also be connected in series between the full-bridge rectifier circuit and the high-voltage side to limit the current flowing through the optocoupler, reduce the probability of optocoupler damage, and thus enable the optocoupler to have a longer service life.

[0013] In some embodiments, the detection branch further includes a high-voltage side filter circuit, the two ends of which are connected to the input and output terminals of the high-voltage side, respectively.

[0014] Based on the above embodiments, the high-voltage side filter circuit is used to eliminate voltage fluctuations entering the optocoupler, so that the state of the optocoupler remains stable when the butterfly valve is in the fully open or fully closed position, ensuring that the controller can detect a stable detection voltage and improving the accuracy of the controller in determining whether the butterfly plate is in the fully open or fully closed position.

[0015] In some embodiments, the high-voltage side filter circuit includes a first filter capacitor, the two plates of which are respectively connected to the input terminal and the output terminal of the high-voltage side.

[0016] In some embodiments, the detection branch further includes a shunt circuit, the two ends of which are connected to the input and output terminals of the high-voltage side, respectively.

[0017] Based on the above embodiments, by using a shunt circuit to reduce the current flowing through the optocoupler, the maximum voltage value that the optocoupler needs to withstand can be reduced, the cost of the optocoupler can be reduced, and the probability of optocoupler damage can be reduced, thereby improving the accuracy of the controller in determining whether the butterfly plate is in the fully open or fully closed position.

[0018] In some embodiments, the shunt circuit includes a shunt resistor, the two ends of which are connected to the input and output terminals of the high-voltage side, respectively.

[0019] In some embodiments, the detection branch further includes a pull-up resistor and a second current-limiting resistor. One end of the pull-up resistor is used to connect to a second preset voltage, and the other end of the pull-up resistor is connected to the input terminal of the low-voltage side. The second preset voltage is less than the first preset voltage. One end of the second current-limiting resistor is connected to the input terminal of the low-voltage side, and the other end of the second current-limiting resistor is used to connect to the controller and output the detection voltage.

[0020] Based on the above embodiments, using a pull-up resistor as a load reduces the probability of short circuit in the detection branch, thereby reducing the probability of damage to the detection branch and giving the detection branch a longer service life, which in turn gives the detection circuit a longer service life; the second current-limiting resistor can prevent large current from entering the controller, reducing the probability of controller damage, so that the controller can obtain the detection voltage and thus determine whether the butterfly plate is in the fully open or fully closed position.

[0021] In some embodiments, the detection branch further includes a low-voltage side filter circuit, the two ends of which are connected to the input and output terminals of the low-voltage side, respectively.

[0022] Based on the above embodiments, the low-voltage side filter circuit can stabilize the detection voltage obtained by the controller, thereby improving the accuracy of the controller in determining whether the butterfly plate is in the fully open or fully closed position.

[0023] In some embodiments, the low-voltage side filter circuit includes a second filter capacitor, the two plates of which are respectively connected to the input terminal and the output terminal of the low-voltage side.

[0024] In some embodiments, the feedback circuit includes two feedback branches. When the butterfly valve is in the fully open position, one feedback branch is triggered to output AC power; when the butterfly valve is in the fully open position, the other feedback branch is triggered to output AC power. The detection circuit includes two detection branches, which are connected to the two feedback branches one-to-one.

[0025] Based on the above embodiments, the controller can easily distinguish the detection voltage corresponding to the butterfly valve being in the fully open position and the detection voltage corresponding to the butterfly valve being in the fully closed position, thereby improving the accuracy of the judgment.

[0026] This application embodiment also provides a butterfly valve detection device, including a circuit board and a butterfly valve. The circuit board is fabricated with a detection circuit. The butterfly valve includes a valve body, a butterfly plate, and a valve stem. The butterfly plate is rotatably disposed inside the valve body. The valve stem is connected to the butterfly plate and extends out of the valve body. When the butterfly plate rotates to the fully open position or the fully closed position, it triggers the feedback circuit to output an AC current with a first preset voltage.

[0027] This application also provides a heating, ventilation, and air conditioning system, including a butterfly valve detection device, a refrigerant transmission pipeline, a drive component, a power supply circuit, and a controller; the butterfly valve is disposed on the refrigerant transmission pipeline; the drive component is connected to the portion of the valve stem extending out of the valve body to drive the butterfly plate to rotate; the power supply circuit is connected to the drive component and is used to supply power to the drive component; the controller is connected to the low-pressure side and the drive component to control the on / off state of the power supply circuit according to the detected voltage.

[0028] Based on the detection circuit of this application, electrical isolation between high-voltage and low-voltage electricity is achieved through an isolation circuit, which improves the overall safety performance of the detection circuit. Furthermore, due to the electrical isolation between the high-voltage and low-voltage sides, the withstand voltage of the low-voltage side components can be reduced, thereby lowering their cost and ultimately reducing the overall cost of the detection circuit while still improving its safety performance. Additionally, the position of the butterfly plate can be determined based on the detected voltage, improving the accuracy and convenience of obtaining the butterfly plate's position. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of a heating, ventilation, and air conditioning system in one embodiment of this application; Figure 2 This is a schematic diagram of the butterfly valve in one embodiment of this application; Figure 3 This is a circuit diagram of the detection circuit, power supply circuit, controller, and driver in one embodiment of this application; Figure 4 This is a framework diagram of the detection branch in one embodiment of this application; Figure 5 This is a circuit diagram of the detection branch in one embodiment of this application.

[0031] Explanation of reference numerals in the attached drawings: 1. HVAC system; 11. Terminal heat exchanger; 12. Medium transmission pipeline; 13. Cold and heat source device; 2. Butterfly valve detection device; 21. Butterfly valve; 211. Valve body; 212. Butterfly plate; 213. Valve stem; 23. Detection circuit; 231. Feedback circuit; 2311. Feedback branch; 2311A. First feedback branch; 2311B. Second feedback branch; 2312. Position detection element; 2313. Feedback loop; 2313A. First feedback loop; 2313B. Second feedback loop; 232. Detection branch; 232A. First detection branch; 232B. Second detection branch; 2321. Rectifier circuit; 2322. Isolation circuit; 2323. Current limiting circuit; 2324. High-pressure side filter circuit; 2325. Shunt circuit; 2326. Low-voltage side filter circuit; 3. Driving component; M1. First power terminal; M2. Second power terminal; M3. Third power terminal; C0. Running capacitor; 4. Power supply circuit; L. Live wire; N. Neutral wire; 41. Control switch; 5. Controller; 51. First detection pin; 52. Second detection pin; K1. First micro switch; K2. Second micro switch; D1. First diode; D2. Second diode; D3. Third diode; D4. Fourth diode; IC. Optocoupler; IC1. Light-emitting element; IC2. Photosensitive element; R1. First current-limiting resistor; R2. Shunt resistor; R3. Pull-up resistor; R4. Second current-limiting resistor; C1. First filter capacitor; C2. Second filter capacitor. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0033] Please refer to Figure 1-4 This application provides a heating, ventilation and air conditioning system 1, including a terminal heat exchange device 11, a medium transmission pipeline 12, a cold and heat source device 13, a butterfly valve detection device 2, a drive component 3, a power supply circuit 4, and a controller 5.

[0034] The terminal heat exchanger 11 is connected to the heat source / cold source device 13 via a medium transmission pipeline 12. The terminal heat exchanger 11 is typically installed indoors to exchange heat with indoor air, thereby producing a cooling or heating effect. The heat source / cold source device 13 is typically installed outdoors to exchange heat with outdoor air. The medium transmission pipeline 12 contains a heat exchange medium, which circulates between the terminal heat exchanger 11 and the heat source / cold source device 13, thus achieving a cooling or heating effect on the indoor environment.

[0035] For example, the medium transmission pipeline 12 may include a refrigerant transmission pipeline 12, the terminal heat exchange device 11 may include a chilled water system, and the heat source device 13 may include a cooling water system. A refrigeration unit is installed on the refrigerant transmission pipeline 12. The heat exchange medium releases heat in the heat source device 13, is cooled by the refrigeration unit, and then absorbs heat in the terminal heat exchange device 11, thereby producing a cooling effect on the room. Large central air conditioning systems, mainly consisting of chilled water units, are used in various large buildings such as skyscrapers, hospitals, shopping malls, and subway stations. The water system pipelines of these large central air conditioning systems are the refrigerant transmission pipeline 12, and the water in the water system pipelines is the heat exchange medium.

[0036] The butterfly valve detection device 2 includes a butterfly valve 21, which includes a valve housing 211, a butterfly plate 212, and a valve stem 213. The butterfly plate 212 is rotatably disposed inside the valve housing 211. The valve stem 213 is connected to the butterfly plate 212 and extends out of the valve housing 211. The valve housing 211 is disposed on the refrigerant transmission pipeline 12. The valve stem 213 drives the butterfly plate 212 to rotate relative to the valve housing 211. When the butterfly plate 212 is not perpendicular to the flow direction of the heat exchange medium, the heat exchange medium can pass through the butterfly valve 21. When the butterfly plate 212 is parallel to the flow direction of the heat exchange medium, the butterfly valve 21 is in the fully open position. When the butterfly plate 212 is perpendicular to the flow direction of the heat exchange medium, the butterfly valve 21 is in the fully closed position, and the heat exchange medium cannot pass through the butterfly valve 21, thereby achieving the purpose of controlling the movement of the heat exchange medium in the refrigerant transmission pipeline 12.

[0037] The driving component 3 is connected to the portion of the valve stem 213 extending out of the valve housing 211 via a transmission connection, thereby driving the butterfly plate 212 to rotate. For example, the output shaft of the driving component 3 can be directly and coaxially fixedly connected to the valve stem 213 to directly drive the valve stem 213 to rotate, thus causing the butterfly plate 212 to rotate. Alternatively, the driving component 3 can also drive a transmission structure to rotate. This transmission structure is connected to the valve stem 213, allowing the driving component 3 to drive the valve stem 213 to rotate via the transmission structure, which in turn causes the butterfly plate 212 to rotate. The transmission structure can include a gear transmission structure or a belt transmission structure. In this embodiment, the specific form of driving the valve stem 213 to rotate is not limited.

[0038] The power supply circuit 4 is connected to the drive unit 3 and is used to supply power to the drive unit 3.

[0039] The controller 5 is connected to the drive unit 3 and is used to control the on / off state of the power supply circuit 4, so as to control the output shaft of the drive unit 3 to stop rotating, or to control the output shaft of the drive unit 3 to rotate in different directions.

[0040] Please refer to Figure 1-3Specifically, the drive unit 3 can be a single-phase capacitor-type asynchronous motor. The drive unit 3 has a first power connection terminal M1, a second power connection terminal M2, and a third power connection terminal M3. A running capacitor C0 is connected between the first power connection terminal M1 and the second power connection terminal M2 of the drive unit 3. The power supply circuit 4 includes a live wire L, a neutral wire N, and a control switch 41. The input terminal of the live wire L is used to connect to the mains live wire L. The control switch 41 enables the output terminal of the live wire L to be connected to at most one of the first power connection terminal M1 and the second power connection terminal M2 of the drive unit 3. The input terminal of the neutral wire N is used to connect to the mains neutral wire N. The output terminal of the neutral wire N is connected to the third power connection terminal M3 of the drive unit 3.

[0041] The control switch 41 has a first energized state, a second energized state, and a de-energized state. When the control switch 41 is in the first energized state, the output terminal of the live wire L is connected to the first energized terminal M1 of the drive component 3, so that the drive component 3 can rotate in the first direction, and the butterfly plate 212 can rotate in the first direction, thereby allowing the butterfly valve 21 to switch from the fully closed position to the fully open position. When the control switch 41 is in the second energized state, the output terminal of the live wire L is connected to the second energized terminal M2 of the drive component 3, so that the drive component 3 can rotate in the second direction, and the butterfly plate 212 can rotate in the second direction, thereby allowing the butterfly valve 21 to switch from the fully open position to the fully closed position. The second direction is opposite to the first direction. When the control switch 41 is in the de-energized state, the output terminal of the live wire L is disconnected from both the first energized terminal M1 and the second energized terminal M2 of the drive component 3.

[0042] Understandably, control switch 41 can be connected to controller 5 so that controller 5 can control the on / off state of control switch 41. Of course, control switch 41 can also be manually controlled to maintain its on / off state.

[0043] However, in related technologies, since the refrigerant transmission pipeline 12 is in a closed state, it is not easy to determine whether the butterfly plate 212 is in the fully open or fully closed position, which can easily cause inconvenience to the operator.

[0044] Based on the above, please refer to Figure 1-3 The butterfly valve detection device 2 also includes a detection circuit 23, which is connected to the controller 5 and can output a detection voltage to the controller 5 when the butterfly valve 21 is in the fully open or fully closed position, so that the controller 5 can determine the position of the butterfly plate 212 based on the detection voltage.

[0045] Please refer to Figure 1-3Specifically, the detection circuit 23 includes a feedback circuit 231 and at least one detection branch 232. When the butterfly valve 21 is in the fully open or fully closed position, the feedback circuit 231 is triggered to output AC power with a first preset voltage. The detection branch 232 includes a rectifier circuit 2321 and an isolation circuit 2322. The rectifier circuit 2321 is connected to the feedback circuit 231 and is used to connect AC power and rectify the rectifier circuit 2321 into DC power. The high-voltage side of the isolation circuit 2322 is connected to the rectifier circuit 2321 to connect DC power, and the low-voltage side of the isolation circuit 2322 is used to output the detection voltage. The controller 5 can determine the position of the butterfly plate 212 based on the detection voltage, thereby improving the accuracy and convenience of obtaining the position of the butterfly plate 212. The isolation circuit 2322 can isolate the DC power on the high-voltage side from the detection voltage on the low-voltage side.

[0046] Please refer to Figure 1-3 In this embodiment, when the controller 5 controls the control switch 41 to be in the first energized state, the output terminal of the live wire L is connected to the first energized terminal M1 of the drive component 3, so that the drive component 3 can rotate in the first direction, so that the butterfly plate 212 can rotate in the first direction, thereby enabling the butterfly valve 21 to switch from the fully closed position to the fully open position until the butterfly valve 21 is in the fully open position. At this time, the feedback circuit 231 can output AC power with a first preset voltage, and the detection branch 232 can output a detection voltage according to the AC power, so that the controller 5 can obtain the detection voltage to obtain the position information of the butterfly valve 21 in the fully open position.

[0047] When the controller 5 controls the control switch 41 to be in the second energized state, the output terminal of the live wire L is connected to the second energized terminal M2 of the drive component 3, so that the drive component 3 can rotate in the second direction, so that the butterfly plate 212 can rotate in the second direction, thereby enabling the butterfly valve 21 to switch from the fully open position to the fully closed position until the butterfly valve 21 is in the fully closed position. At this time, the feedback circuit 231 can output AC power with a first preset voltage, and the detection branch 232 can output a detection voltage according to the AC power, so that the controller 5 can obtain the detection voltage to obtain the position information of the butterfly valve 21 in the fully closed position.

[0048] When the controller 5 obtains the position information of the butterfly valve 21 being in the fully open position or the position information of the butterfly valve 21 being in the fully closed position, the controller 5 can control the control switch 41 to switch to the power-off state, so as to de-energize the drive component 3, thereby stopping the drive component 3 from rotating, achieving the purpose of saving energy consumption; it can also reduce the probability of damage to the drive component 3 and the butterfly valve 21, and improve the overall stability of the HVAC system 1.

[0049] Furthermore, the electrical isolation between high voltage and low voltage is achieved through the isolation circuit 2322, which can improve the overall safety performance of the detection circuit 23. Also, due to the electrical isolation between the high voltage side and the low voltage side, the withstand voltage value of the low voltage side components can be reduced, thereby reducing the cost of the low voltage side components. This can reduce the overall cost of the detection circuit 23 and improve the overall safety performance of the detection circuit 23.

[0050] Please refer to Figure 1-3 Furthermore, to facilitate the controller 5 in distinguishing between the detection voltage corresponding to the butterfly valve 21 being in the fully open position and the detection voltage corresponding to the butterfly valve 21 being in the fully closed position, the feedback circuit 231 includes two feedback branches 2311. When the butterfly valve 21 is in the fully open position, one feedback branch 2311 is triggered to output AC power; when the butterfly valve 21 is in the fully open position, the other feedback branch 2311 is triggered to output AC power. The detection circuit 23 includes two detection branches 232, which are connected one-to-one with the two feedback branches 2311.

[0051] Please refer to Figure 1-3 Specifically, the two feedback branches 2311 can be a first feedback branch 2311A and a second feedback branch 2311B, respectively, and the two detection branches 232 can be a first detection branch 232A and a second detection branch 232B, respectively. The first detection branch 232A is connected to the first feedback branch 2311A and to the first detection pin 51 of the controller 5; the second detection branch 232B is connected to the second feedback branch 2311B and to the second detection pin 52 of the controller 5.

[0052] When the butterfly valve 21 is in the fully open position, the first feedback branch 2311A can output AC power with a first preset voltage, and the first detection branch 232A can output a detection voltage according to the AC power, so that the first detection pin 51 of the controller 5 can obtain the detection voltage to obtain the position information of the butterfly valve 21 in the fully open position.

[0053] When the butterfly valve 21 is in the fully closed position, the second feedback branch 2311B can output AC power with a second preset voltage, and the second detection branch 232B can output a detection voltage according to the AC power, so that the second detection pin 52 of the controller 5 can obtain the detection voltage to obtain the position information of the butterfly valve 21 in the fully open position.

[0054] By acquiring the detection voltage through the first detection pin 51 or the second detection pin 52 of the controller 5, it can be determined whether the butterfly valve 21 is in the fully open position or not, thereby improving the accuracy of the butterfly valve 21 position acquired by the controller 5.

[0055] It can be understood that a first indicator can be connected to the first feedback branch 2311A, and a second indicator can be connected to the second feedback branch 2311B. The first indicator can issue a first indicator message when the first feedback branch 2311A is triggered; the second indicator can issue a second indicator message when the second feedback branch 2311B is triggered. In this case, only one detection branch 232 can be connected to both the first feedback branch 2311A and the second feedback branch 2311B simultaneously, so that a detection voltage can be output to the controller 5 when either feedback circuit 231 is triggered. When the controller 5 obtains the detection voltage and the first indicator issues the first indicator message, it indicates that the butterfly valve 21 is in the fully open position; when the controller 5 obtains the detection voltage and the second indicator issues the second indicator message, it indicates that the butterfly valve 21 is in the fully closed position. The position of the butterfly valve 21 can also be obtained, improving the accuracy of the butterfly valve 21 position obtained by the controller 5.

[0056] For example, the first and second prompts can be at least one of a display screen, a buzzer, and an indicator light. The first and second prompt messages can be at least one of text, sound, and light, and the first and second prompt messages can be the same or different. In other embodiments, the first and second prompts can also be in other forms, and the first and second prompt messages can also be in other forms. In the embodiments of this application, there is no limitation on the specific forms of the first and second prompts, the first prompt message, and the second prompt message.

[0057] Of course, in other embodiments, the controller 5 can also distinguish the detection voltage corresponding to the butterfly valve 21 being in the fully open position and the detection voltage corresponding to the butterfly valve 21 being in the fully closed position through other means. In this embodiment, no specific limitation is made in this regard.

[0058] Of course, for different driving components 3, a power supply circuit 4 can be designed specifically to realize the forward and reverse rotation of the driving component 3, and a detection circuit 23 can be designed according to requirements to realize the position detection of the butterfly valve 21. In this embodiment, no specific limitations are made.

[0059] Please refer to Figure 1-3In one embodiment, each feedback branch 2311 may include a position detection element 2312 and a feedback loop 2313. The detection branch 232 is connected to the feedback loop 2313, and the position detection element 2312 may be disposed within the valve housing 211 to detect the position of the butterfly plate 212. In other embodiments, the position detection element 2312 can also be used to detect the position of the valve stem 213. Of course, the position detection element 2312 can also be used to detect the position of other components to detect the position of the butterfly plate 212. In this embodiment, the specific position of the position detection element 2312 is not limited. It is understood that the position detection element 2312 includes at least one of a microswitch, a photoelectric sensor, and a Hall element; in other embodiments, the position detection element 2312 may also be in other forms. In this embodiment, the specific form of the position detection element 2312 is not limited.

[0060] Please refer to Figure 1-3 In one specific embodiment, the first feedback branch 2311A may include a first micro switch K1 and a first feedback loop 2313A. The moving contact of the first micro switch K1 can be connected to the output terminal of the live wire L. The normally closed contact of the first micro switch K1 is connected to the first power terminal M1 of the driving component 3. The normally open contact of the first micro switch K1 is connected to the first feedback loop 2313A. The first feedback loop 2313A is connected to the neutral wire N and to the first detection branch 232A.

[0061] Please refer to Figure 1-3 The second feedback branch 2311B may include a second micro switch K2 and a second feedback loop 2313B. The moving contact of the second micro switch K2 can be connected to the output terminal of the live wire L. The normally closed contact of the second micro switch K2 is connected to the second power terminal M2 of the driving component 3. The normally open contact of the second micro switch K2 is connected to the second feedback loop 2313B. The second feedback loop 2313B is connected to the neutral wire N and to the second detection branch 232B.

[0062] When the control switch 41 is in the first energized state, the output terminal of the live wire L is connected to the first energized terminal M1 of the drive component 3 through the moving contact and normally closed contact of the first micro switch K1, so that the drive component 3 can rotate in the first direction, so that the butterfly plate 212 can rotate in the first direction, thereby allowing the butterfly valve 21 to switch from the fully closed position to the fully open position. When the butterfly valve 21 is in the fully open position, the first micro switch K1 is triggered, so that the moving contact and normally open contact of the first micro switch K1 are connected, so that the AC live wire L can enter the first feedback loop 2313A, so that the first feedback loop 2313A outputs AC power with a first preset voltage, thereby allowing the first detection branch 232A to output a detection voltage, which is acquired by the first detection pin 51 of the controller 5, so that the controller 5 can determine the position information of the butterfly valve 21 in the fully open position.

[0063] When the control switch 41 is in the second energized state, the output terminal of the live wire L is connected to the second energized terminal M2 of the drive unit 3 through the moving contact and normally closed contact of the second micro switch K2, so that the drive unit 3 can rotate in the second direction, so that the butterfly plate 212 can rotate in the second direction, thereby allowing the butterfly valve 21 to switch from the fully open position to the fully closed position. When the butterfly valve 21 is in the fully closed position, the second micro switch K2 is triggered, so that the moving contact and normally open contact of the second micro switch K2 are connected, so that the AC live wire L can enter the second feedback loop 2313B, so that the second feedback loop 2313B outputs AC power with the first preset voltage, and then the second detection branch 232B can output detection voltage, which is acquired by the second detection pin 52 of the controller 5, so that the controller 5 can determine the position information of the butterfly valve 21 in the fully closed position.

[0064] Since the first detection branch 232A and the second detection branch 232B have the same structure, in this embodiment, either detection branch 232 can be used alone or both detection branches 232 can be used at the same time. The corresponding connection relationship has been described in detail above. In the following embodiments, the first detection branch 232A will be used as an example for explanation.

[0065] Please refer to Figure 3-5 In one embodiment, the first detection branch 232A includes a rectifier circuit 2321 and an isolation circuit 2322. The rectifier circuit 2321 is connected to the feedback circuit 231 and is used to connect to AC power and rectify the rectifier circuit 2321 into DC power. The high-voltage side of the isolation circuit 2322 is connected to the rectifier circuit 2321 to connect to DC power, and the low-voltage side of the isolation circuit 2322 is used to output a detection voltage to isolate the DC power on the high-voltage side from the detection voltage on the low-voltage side.

[0066] The rectifier circuit 2321 includes either a full-bridge rectifier circuit or a half-bridge rectifier circuit, both of which can rectify AC power into DC power. The isolation circuit 2322 includes one of an optocoupler IC, a relay, and a solid-state relay, all of which can achieve electrical isolation between high and low voltage. In other embodiments, the rectifier circuit 2321 and the isolation circuit 2322 can also take other forms. In the embodiments of this application, the specific forms of the rectifier circuit 2321 and the isolation circuit 2322 are not limited.

[0067] Please refer to Figure 3-5 In one embodiment, the rectifier circuit 2321 includes a full-bridge rectifier circuit. The two input terminals of the full-bridge rectifier circuit are used to connect to AC power. Specifically, the live wire input terminal of the full-bridge rectifier circuit is connected to the first feedback branch 2311A, and the neutral wire input terminal of the full-bridge rectifier circuit is connected to the output terminal of the neutral wire N. When the butterfly valve 21 is in the fully open position, the first micro switch K1 is triggered so that the moving contact of the first micro switch K1 is connected to the normally open contact, so that the AC live wire L can enter the first feedback loop 2313A, thereby making the first feedback loop 2313A output AC power with a first preset voltage, and then making the AC power enter the full-bridge rectifier circuit through the live wire input terminal and the neutral wire input terminal of the full-bridge rectifier circuit, so as to be rectified into DC power by the full-bridge rectifier circuit.

[0068] The isolation circuit 2322 includes an optocoupler IC. The high-voltage side input and output terminals of the optocoupler IC are respectively connected to the two output terminals of the full-bridge rectifier circuit. The low-voltage side input and output terminals of the optocoupler IC are used to output the detection voltage and ground, respectively.

[0069] Please refer to Figure 3-5 In one specific embodiment, the full-bridge rectifier circuit includes a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4. The optocoupler IC includes a light-emitting element IC1 and a photosensitive element IC2. The light-emitting element IC1 is located on the high-voltage side of the optocoupler IC, and the input and output terminals of the high-voltage side are the input and output terminals of the light-emitting element IC1, respectively. The photosensitive element IC2 is located on the low-voltage side of the optocoupler IC, and the input and output terminals of the low-voltage side are the input and output terminals of the photosensitive element IC2, respectively.

[0070] The anode of the first diode D1 is connected to the live wire input of the full-bridge rectifier circuit, and the cathode of the first diode D1 is connected to the input of the light-emitting element IC1. The anode of the second diode D2 is connected to the neutral wire input of the full-bridge rectifier circuit, and the cathode of the second diode D2 is connected to the cathode of the first diode D1. The anode of the third diode D3 is connected to the output of the light-emitting element IC1, and the cathode of the third diode D3 is connected to the anode of the first diode D1. The anode of the fourth diode D4 is connected to the anode of the third diode D3, and the cathode of the fourth diode D4 is connected to the anode of the second diode D2. The input of the photosensitive element IC2 is used to connect to a second preset voltage and is connected to the first detection pin 51 of the controller 5, so that the input of the photosensitive element IC2 can output a detection voltage to the controller 5, and the output of the photosensitive element IC2 is grounded.

[0071] When the butterfly plate 212 is not in the fully open position, the output of the first feedback branch 2311A is disconnected, and there is no voltage input at the input terminal of the full-bridge rectifier circuit, so that there is no voltage output at the output terminal of the full-bridge rectifier circuit. The light-emitting element IC1 does not emit light, and the photosensitive element IC2 is in the disconnected state, so that the second preset voltage can be output as the detection voltage to the first detection pin 51 of the controller 5, thereby causing the first detection pin 51 of the controller 5 to detect a high-level detection voltage. At this time, the controller 5 determines that the butterfly plate 212 is not in the fully open position.

[0072] When the butterfly valve 21 is in the fully open position, the first feedback branch 2311A is turned on, so that the input terminal of the full-bridge rectifier circuit can receive AC power with a first preset voltage, so that the output terminal of the full-bridge rectifier circuit outputs DC power, the light-emitting element IC1 emits light, so that the photosensitive element IC2 is turned on, and the second preset voltage can be grounded through the photosensitive element IC2, so that the grounded voltage is used as the detection voltage and output to the first detection pin 51 of the controller 5, thereby making the first detection pin 51 of the controller 5 detect a low-level detection voltage. At this time, the controller 5 determines that the butterfly plate 212 is in the fully open position.

[0073] Please refer to Figure 3-5 It is understandable that when the butterfly plate 212 is not in the fully closed position, the output of the second feedback branch 2311B is disconnected, and in the second detection branch 232B, there is no voltage input at the input terminal of the full-bridge rectifier circuit, so that there is no voltage output at the output terminal of the full-bridge rectifier circuit. The light-emitting element IC1 does not emit light, and the photosensitive element IC2 is in the disconnected state, so that the second preset voltage can be output as the detection voltage to the second detection pin 52 of the controller 5, thereby causing the second detection pin 52 of the controller 5 to detect a high-level detection voltage. At this time, the controller 5 determines that the butterfly plate 212 is not in the fully closed position.

[0074] When the butterfly valve 21 is in the fully closed position, the second feedback branch 2311B is turned on, so that the input terminal of the full-bridge rectifier circuit in the second detection branch 232B can receive AC power with a first preset voltage, so that the output terminal of the full-bridge rectifier circuit outputs DC power, the light-emitting element IC1 emits light, so that the photosensitive element IC2 is turned on, and the second preset voltage can be grounded through the photosensitive element IC2, so that the grounded voltage is output as the detection voltage to the second detection pin 52 of the controller 5, thereby making the second detection pin 52 of the controller 5 detect a low-level detection voltage. At this time, the controller 5 determines that the butterfly plate 212 is in the fully closed position.

[0075] Please refer to Figure 3-5 In one embodiment, the detection branch 232 may include a current limiting circuit 2323, which is connected in series between the feedback circuit 231 and the full-bridge rectifier circuit. Specifically, the first detection branch 232A may include a current limiting circuit 2323, which is connected in series between the first feedback branch 2311A and the full-bridge rectifier circuit. The current limiting circuit 2323 limits the current flowing through the full-bridge rectifier circuit, thereby reducing the current carried by the full-bridge rectifier circuit. This reduces the cost and size of the full-bridge rectifier circuit, thus reducing the overall cost and size of the first detection branch 232A and improving the overall convenience of use, installation, and transportation of the butterfly valve detection device 2.

[0076] Understandably, the current limiting circuit 2323 can also be connected in series between the full-bridge rectifier circuit and the high-voltage side to limit the current flowing through the high-voltage side. Specifically, the current limiting circuit 2323 can be connected in series between the positive terminal of the first diode D1 and the positive terminal of the light-emitting element IC1 to limit the current flowing through the light-emitting element IC1, thereby reducing the probability of damage to the light-emitting element IC1 and enabling it to have a longer service life, which in turn enables the optocoupler IC to have a longer service life.

[0077] Please refer to Figure 3-5 In one specific embodiment, the current limiting circuit 2323 may include a first current limiting resistor R1, which is connected in series between the output terminal of the feedback circuit 231 and the input terminal of the full-bridge rectifier circuit. Specifically, the first current limiting resistor R1 is connected in series between the first feedback branch 2311A and the full-bridge rectifier circuit to limit the current flowing through the full-bridge rectifier circuit, thereby reducing the current carried by the full-bridge rectifier circuit, and thus reducing the cost and size of the full-bridge rectifier circuit. This reduces the overall cost and size of the first detection branch 232A, and improves the convenience of use, installation, and transportation of the butterfly valve detection device 2.

[0078] Understandably, the first current-limiting resistor R1 can also be connected in series between the full-bridge rectifier circuit and the high-voltage side. Specifically, the first current-limiting resistor R1 can be connected in series between the positive terminal of the first diode D1 and the positive terminal of the light-emitting element IC1 to limit the current flowing through the light-emitting element IC1, reduce the probability of damage to the light-emitting element IC1, and enable the light-emitting element IC1 to have a longer service life, thereby enabling the optocoupler IC to have a longer service life.

[0079] Please refer to Figure 3-5 In one embodiment, the detection branch 232 further includes a high-voltage side filter circuit 2324, with its two ends connected to the input and output terminals of the high-voltage side, respectively. Specifically, the first detection branch 232A also includes a high-voltage side filter circuit 2324, with its two ends connected to the input and output terminals of the light-emitting element IC1, respectively. This high-voltage side filter circuit 2324 eliminates voltage fluctuations entering the light-emitting element IC1, ensuring stable light emission from the light-emitting element IC1 when the butterfly valve 21 is in the fully open position. This, in turn, maintains a stable conduction state for the photosensitive element IC2, ensuring that the first detection pin 51 of the controller 5 can detect a stable low-level detection voltage, thereby improving the accuracy of the controller 5 in determining that the butterfly plate 212 is in the fully open position.

[0080] Please refer to Figure 3-5 It is understandable that when the butterfly valve 21 is in the fully closed position, the light-emitting element IC1 emits light stably, thereby maintaining the conduction state of the photosensitive element IC2 stably. This ensures that the second detection pin 52 of the controller 5 can detect a stable low-level detection voltage, improving the accuracy of the controller 5 in determining that the butterfly plate 212 is in the fully closed position.

[0081] Please refer to Figure 3-5 In one specific embodiment, the high-voltage side filter circuit 2324 includes a first filter capacitor C1. The two plates of the first filter capacitor C1 are connected to the input terminal and the output terminal of the high-voltage side, respectively. The first filter capacitor C1 eliminates the voltage fluctuations entering the light-emitting element IC1, so that the light-emitting element IC1 can emit light stably when the butterfly valve 21 is in the fully open or fully closed position. This keeps the conduction state of the photosensitive element IC2 stable, ensuring that the first detection pin 51 of the controller 5 can detect a stable low-level detection voltage, or the second detection pin 52 of the controller 5 can detect a stable low-level detection voltage, thereby improving the accuracy of the controller 5 in determining whether the butterfly plate 212 is in the fully open or fully closed position.

[0082] Please refer to Figure 3-5In one embodiment, the detection branch 232 further includes a shunt circuit 2325, with its two ends connected to the input and output terminals of the high-voltage side, respectively. Specifically, the first detection branch 232A may include a shunt circuit 2325, which is connected to the input and output terminals of the light-emitting element IC1, respectively. This reduces the current flowing through the light-emitting element IC1, thereby lowering the maximum voltage that the light-emitting element IC1 needs to withstand, reducing its cost, and consequently reducing the cost of the optocoupler IC. It also reduces the probability of damage to the optocoupler IC, thus improving the accuracy of the controller 5 in determining that the butterfly plate 212 is in the fully open position. It is understood that this also improves the accuracy of the controller 5 in determining that the butterfly plate 212 is in the fully closed position.

[0083] Please refer to Figure 3-5 In one specific embodiment, the shunt circuit 2325 includes a shunt resistor R2, the two ends of which are connected to the input terminal and the output terminal of the high-voltage side, respectively. By reducing the current flowing through the light-emitting element IC1 through the shunt resistor R2, the maximum voltage value that the light-emitting element IC1 needs to withstand can be reduced, thereby reducing the cost of the light-emitting element IC1, and further reducing the cost of the optocoupler IC. It can also reduce the probability of damage to the optocoupler IC, thereby improving the accuracy of the controller 5 in determining whether the butterfly plate 212 is in the fully open or fully closed position.

[0084] Please refer to Figure 3-5 In one embodiment, the detection branch 232 further includes a pull-up resistor R3 and a second current-limiting resistor R4. One end of the pull-up resistor R3 is used to connect to a second preset voltage, and the other end of the pull-up resistor R3 is connected to the input terminal of the low-voltage side. The second preset voltage is less than the first preset voltage. One end of the second current-limiting resistor R4 is connected to the input terminal of the low-voltage side, and the other end of the second current-limiting resistor R4 is used to connect to the controller 5 and output the detection voltage.

[0085] Please refer to Figure 3-5Specifically, the first detection branch 232A also includes a pull-up resistor R3 and a second current-limiting resistor R4. One end of the pull-up resistor R3 is used to connect to a second preset voltage, and the other end of the pull-up resistor R3 is connected to the input terminal of the photosensitive element IC2. When the photosensitive element IC2 is turned on, the pull-up resistor R3 is used as a load to reduce the probability of short circuit in the first detection branch 232A, thereby reducing the probability of damage to the first detection branch 232A and giving the detection branch 232 a longer service life, which in turn gives the detection circuit 23 a longer service life. One end of the second current-limiting resistor R4 is connected to the input terminal of the photosensitive element IC2, and the other end of the second current-limiting resistor R4 is used to connect to the first detection pin 51 of the controller 5 and output a detection voltage to prevent large current from entering the controller 5, reducing the probability of damage to the controller 5, so that the controller 5 can obtain the detection voltage through the first detection pin 51 and thus determine whether the butterfly plate 212 is in the fully open position.

[0086] Please refer to Figure 3-5 It is understandable that in the second detection branch 232B, the probability of short circuit in the second detection branch 232B can also be reduced by the pull-up resistor R3, thereby reducing the probability of damage to the detection branch 232 and giving the second detection branch 232B a longer service life, which in turn gives the detection circuit 23 a longer service life; the second current limiting resistor R4 can prevent large current from entering the controller 5, reducing the probability of damage to the controller 5, so that the controller 5 can obtain the detection voltage through the second detection pin 52, and thus determine whether the butterfly plate 212 is in the fully closed position.

[0087] Please refer to Figure 3-5 In one embodiment, the detection branch 232 further includes a low-voltage side filter circuit 2326, with its two ends connected to the input and output terminals of the low-voltage side, respectively. Specifically, the first detection branch 232A also includes a low-voltage side filter circuit 2326, with its two ends connected to the input and output terminals of the photosensitive element IC2, respectively. This low-voltage side filter circuit 2326 stabilizes the detection voltage obtained from the first detection pin 51 of the controller 5, thereby improving the accuracy of the controller 5 in determining whether the butterfly plate 212 is in the fully open position. Similarly, in the second detection branch 232B, the low-voltage side filter circuit 2326 can also stabilize the detection voltage obtained from the second detection pin 52 of the controller 5, thereby improving the accuracy of the controller 5 in determining whether the butterfly plate 212 is in the fully closed position.

[0088] Please refer to Figure 3-5 In one specific embodiment, the low-voltage side filter circuit 2326 includes a second filter capacitor C2, the two plates of which are respectively connected to the input terminal and the output terminal of the low-voltage side.

[0089] Please refer to Figure 3-5 Specifically, the two plates of the second filter capacitor C2 are connected to the first detection pin 51 of the controller 5 and the output terminal of the photosensitive element IC2, respectively, so as to stabilize the detection voltage obtained by the first detection pin 51 of the controller 5, thereby improving the accuracy of the controller 5 in determining whether the butterfly plate 212 is in the fully open position.

[0090] Please refer to Figure 3-5 It is understandable that the two plates of the second filter capacitor C2 can also be connected to the second detection pin 52 of the controller 5 and the output terminal of the photosensitive element IC2 respectively, so as to stabilize the detection voltage obtained by the second detection pin 52 of the controller 5 using the second filter capacitor C2, thereby improving the accuracy of the controller 5 in determining whether the butterfly plate 212 is in the fully closed position.

[0091] Please refer to Figure 3-5 In one embodiment, the butterfly valve detection device 2 further includes a circuit board with a detection circuit 23. The detection circuit 23 is formed on the circuit board by etching, which can improve the manufacturing efficiency and quality of the detection circuit 23.

[0092] In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" 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, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0093] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0094] In the description of this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0095] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0096] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A detection circuit for a butterfly valve, characterized in that, include: The feedback circuit is triggered to output AC power with a first preset voltage when the butterfly valve is in the fully open or fully closed position. as well as At least one detection branch, the detection branch comprising: A rectifier circuit, connected to the feedback circuit, is used to receive the AC power and rectify the AC power into DC power. as well as An isolation circuit is provided, with the high-voltage side connected to the rectifier circuit to receive the DC power, and the low-voltage side used to output a detection voltage to isolate the DC power on the high-voltage side from the detection voltage on the low-voltage side.

2. The detection circuit as described in claim 1, characterized in that, The rectifier circuit includes a full-bridge rectifier circuit or a half-bridge rectifier circuit; The isolation circuit includes one of an optocoupler, a relay, and a solid-state relay.

3. The detection circuit as described in claim 1, characterized in that, The rectifier circuit includes a full-bridge rectifier circuit, and the two input terminals of the full-bridge rectifier circuit are used to connect to the AC power. The isolation circuit includes an optocoupler. The high-voltage side input and output terminals of the optocoupler are respectively connected to the two output terminals of the full-bridge rectifier circuit. The low-voltage side input and output terminals of the optocoupler are respectively used to output the detection voltage and ground.

4. The detection circuit as described in claim 3, characterized in that, The detection branch also includes: A current limiting circuit is connected in series between the feedback circuit and the full-bridge rectifier circuit to limit the current flowing through the full-bridge rectifier circuit, or it is connected in series between the full-bridge rectifier circuit and the high-voltage side to limit the current flowing through the high-voltage side.

5. The detection circuit as described in claim 4, characterized in that, The current limiting circuit includes: The first current-limiting resistor is connected in series between the output terminal of the feedback circuit and the input terminal of the full-bridge rectifier circuit, or in series between the output terminal of the full-bridge rectifier circuit and the input terminal of the high-voltage side.

6. The detection circuit as described in claim 3, characterized in that, The detection branch also includes: The high-voltage side filter circuit has its two ends connected to the input terminal and the output terminal of the high-voltage side, respectively.

7. The detection circuit as described in claim 6, characterized in that, The high-voltage side filter circuit includes: The first filter capacitor has two plates connected to the input terminal and the output terminal of the high-voltage side, respectively.

8. The detection circuit as described in claim 3, characterized in that, The detection branch also includes: The shunt circuit is connected at both ends to the input terminal and the output terminal of the high-voltage side, respectively.

9. The detection circuit as described in claim 8, characterized in that, The shunt circuit includes: The shunt resistor is connected at both ends to the input terminal and the output terminal of the high-voltage side, respectively.

10. The detection circuit as described in claim 3, characterized in that, The detection branch also includes: A pull-up resistor, one end of which is connected to a second preset voltage, and the other end connected to the input terminal of the low-voltage side, wherein the second preset voltage is less than the first preset voltage; and The second current-limiting resistor has one end connected to the input terminal of the low-voltage side, and the other end used to connect to the controller and output the detection voltage.

11. The detection circuit as described in claim 10, characterized in that, The detection branch also includes: The low-voltage side filter circuit has its two ends connected to the input terminal and the output terminal of the low-voltage side, respectively.

12. The detection circuit as described in claim 11, characterized in that, The low-voltage side filter circuit includes: The second filter capacitor has two plates connected to the input terminal and the output terminal of the low-voltage side, respectively.

13. The detection circuit according to any one of claims 1-12, characterized in that, The feedback circuit includes two feedback branches. When the butterfly valve is in the fully open position, one of the feedback branches is triggered to output the AC power; when the butterfly valve is in the fully open position, the other feedback branch is triggered to output the AC power. The detection circuit includes two detection branches, which are connected to the two feedback branches one-to-one.

14. A butterfly valve detection device, characterized in that, include: A circuit board having a detection circuit as described in any one of claims 1-13; A butterfly valve includes a valve body, a butterfly plate, and a valve stem. The butterfly plate is rotatably disposed inside the valve body, and the valve stem is connected to the butterfly plate and extends out of the valve body. When the butterfly plate rotates to the fully open or fully closed position, it triggers the feedback circuit to output an AC current with a first preset voltage.

15. A heating, ventilation, and air conditioning system, characterized in that, include: The butterfly valve detection device as described in claim 14; A refrigerant transmission pipeline, wherein the butterfly valve is installed on the refrigerant transmission pipeline; A driving component is connected to the portion of the valve stem that extends out of the valve housing to drive the butterfly plate to rotate; A power supply circuit is connected to the driving component and is used to supply power to the driving component; as well as A controller, connected to the low-voltage side and the drive unit, controls the on / off state of the power supply circuit based on the detected voltage.

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