Boiler flame detection cooling air start-stop control circuit and boiler flame detection system

Abstract

The utility model relates to a boiler flame detection cooling air start-stop control circuit and a boiler flame detection system. The start-stop control circuit comprises a power supply loop, a remote / local switching loop, a fan start loop and a fan stop loop. The power supply loop is respectively connected with the remote / local switching loop, the fan starting loop and the fan stopping loop; the output end of the remote / local switching loop is respectively connected with the fan starting loop and the fan stopping loop; a first control end of the fan starting loop is connected to the remote / local switching loop, a second control end is connected to the remote DCS system, and an output end is connected to the cooling fan; a first control end of the fan shutdown loop is connected to the remote / local switching loop, a second control end is connected to the remote DCS system, and an output end is connected to the cooling fan. The fire detection cooling fan can be started and stopped locally and remotely by the DCS, so that the safety risk of starting the fire detection cooling fan locally by an operator is reduced, and the working efficiency of a production field is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fire detection equipment control, in particular to a boiler fire detection cooling air start-stop control circuit and a boiler flame detection system. BACKGROUND

[0002] The flame detection system of a thermal power unit boiler is the core equipment for ensuring the safe and stable combustion of the boiler, and the safe and reliable guarantee of the flame detection system ensures the stability of the boiler from ignition to grid connection with load. The flame detection system of the boiler mainly consists of a fire detection cooling fan, a fire detection probe, a flame detection amplifier, a flame detection card and the like, wherein the fire detection cooling fan provides a cooling air source and a purge air source for the fire detection probe and the fire detection optical fiber of the fire detection system, so as to ensure the normal working temperature of the fire detection equipment for long-term stable operation. When the boiler is ignited, the temperature of the combustion of the pulverized coal or oil in the furnace may be higher than the normal working temperature of the fire detection probe. If the fire detection probe is operated in a high-temperature environment for a long time, the flame detection may be invalid, the fire detection probe may be damaged, or the boiler MFT action may be triggered, resulting in the shutdown of the boiler and the extinguishing of the fire. The fire detection cooling air can solve the defect. The fire detection cooling fan sends the cooling air to the fire detection probe through the flame detection system pipe, so as to provide a cooling air source for the fire detection equipment, ensure that the fire detection equipment can work at a safe and normal temperature, and provide a purge air source for the flame detection system pipe, so as to ensure that there is no dust accumulation at the flame detection probe and the flame detection probe can correctly complete the detection task.

[0003] However, the current start-stop control circuit of the boiler fire detection cooling fan is only provided with an on-site operation button, and remote start-stop control cannot be realized. Therefore, the operating personnel need to manually start and stop the cooling fan on site during each start-stop process of the unit, which increases the labor intensity of the operating personnel and also brings certain work pressure to the maintenance personnel. Practical new type content

[0004] The present application provides a boiler fire detection cooling air start-stop control circuit and a boiler flame detection system, so as to at least solve the problem that the boiler fire detection cooling fan cannot be remotely started and stopped in the related art.

[0005] In a first aspect, the present application provides a boiler fire detection cooling air start-stop control circuit, which is applied to a flame detection system comprising a cooling fan, and the start-stop control circuit comprises a power supply circuit, a remote / local switching circuit, a fan starting circuit and a fan stopping circuit; wherein,

[0006] The power supply circuit is connected with the remote / local switching circuit, the fan starting circuit and the fan stopping circuit respectively; the output end of the remote / local switching circuit is connected with the fan starting circuit and the fan stopping circuit respectively; the first control end of the fan starting circuit is connected with the remote / local switching circuit, the second control end is connected with the remote DCS system, and the output end is connected with the cooling fan; the first control end of the fan stopping circuit is connected with the remote / local switching circuit, the second control end is connected with the remote DCS system, and the output end is connected with the cooling fan;

[0007] The power supply circuit is used for providing working voltage; when the remote / local switching circuit is in the first state, the fan starting circuit and the fan stopping circuit are in the local control state; when the remote / local switching circuit is in the second state, the fan starting circuit and the fan stopping circuit are in the remote control state; when the fan starting circuit is turned on, the cooling fan starts; and when the fan stopping circuit is turned on, the cooling fan stops.

[0008] In an embodiment, the remote / local switching circuit comprises a switching operation switch connected with the first control end of the fan starting circuit and the fan stopping circuit respectively; wherein,

[0009] When the switching operation switch is turned off, the remote / local switching circuit is in the first state, and the fan starting circuit and the fan stopping circuit are in the local control state; when the switching operation switch is turned on, the remote / local switching circuit is in the second state, and the fan starting circuit and the fan stopping circuit are in the remote control state.

[0010] In an embodiment, the fan starting circuit comprises a first remote / local switching switch, a local starting circuit, a remote starting circuit, a fan stopping switch and a fan triggering circuit;

[0011] The local starting circuit and the remote starting circuit are arranged in parallel between the first remote / local switching switch and the fan stopping switch, the fan triggering circuit is arranged between the fan stopping switch and the cooling fan of the cooling fan, the control end of the first remote / local switching switch serves as the first control end of the fan starting circuit, and the control end of the remote starting circuit is connected with the remote DCS system;

[0012] Specifically, when the fan starting circuit is in local control mode, the first remote / local switching switch is connected to the local starting circuit; when the fan starting circuit is in remote control mode, the first remote / local switching switch is connected to the remote starting circuit; when the local or remote starting circuit is activated, the fan triggering circuit is activated and drives the cooling fan to run; before receiving a fan shutdown signal, the fan shutdown switch is in the closed state.

[0013] In one embodiment, the wind turbine shutdown circuit includes a second remote / local switching switch, a local shutdown circuit, and a remote shutdown circuit;

[0014] The local shutdown circuit and the remote shutdown circuit are connected in parallel between the second remote / local switching switch and the wind turbine shutdown switch. The control terminal of the second remote / local switching switch serves as the first control terminal of the wind turbine shutdown circuit, and the control terminal of the remote shutdown circuit is connected to the remote DCS system.

[0015] Specifically, when the wind turbine shutdown circuit is in local control mode, the second remote / local switch is connected to the local shutdown circuit; when the wind turbine shutdown circuit is in remote control mode, the remote / local switch is connected to the remote shutdown circuit; when the local shutdown circuit or the remote shutdown circuit is connected, the wind turbine shutdown switch is disconnected.

[0016] In one embodiment, the fan triggering circuit includes a motor AC contactor and a motor starter; wherein,

[0017] The motor AC contactor and the motor starter are connected in series; when the local starting circuit or the remote starting circuit is turned on, the motor AC contactor is triggered to close, thereby driving the motor starter to run.

[0018] In one embodiment, the local start circuit includes a local manual start switch, and the local stop circuit includes a local manual stop switch;

[0019] The local manual start switch and the local manual stop switch are installed in the actual application site of the flame detection system.

[0020] The remote start circuit includes a first electronic switch, and the remote stop circuit includes a second electronic switch. The control terminals of the first and second electronic switches serve as the second control terminals of the wind turbine start circuit and the wind turbine stop circuit, respectively, and are connected to the remote DCS system.

[0021] The first electronic switch is turned on by a remote start signal issued by the remote DCS system; the second electronic switch is turned on by a remote stop signal issued by the remote DCS system.

[0022] In one embodiment, the power supply circuit includes a power supply, a power switch, and a power relay, wherein the power relay is connected to the power supply via the power switch;

[0023] When the power switch is closed, the power supply provides operating voltage to the remote / local switching circuit, the fan start circuit, and the fan stop circuit, and the power relay is closed.

[0024] In one embodiment, the start / stop control circuit includes a power indicator light, a local operation indicator light, a remote operation indicator light, a fan operation indicator switch, a fan operation indicator light, and a fan stop indicator light;

[0025] The power indicator light is connected to the power supply circuit and illuminates when the power supply is normal.

[0026] The local operation indicator and the remote operation indicator are respectively connected to the remote / local switching circuit. When the remote / local switching circuit is in the first state, the local operation indicator lights up; when the remote / local switching circuit is in the second state, the remote operation indicator lights up.

[0027] The fan operation indicator switch and the fan operation indicator light are connected in series to the fan start circuit. When the fan start circuit is turned on, the fan operation indicator light will light up.

[0028] The fan shutdown indicator light is connected to the fan shutdown circuit. When the fan shutdown circuit is turned on, the fan shutdown indicator light will illuminate.

[0029] Secondly, embodiments of this application provide a boiler flame detection system, including a cooling fan and a start / stop control circuit for the boiler flame detection cooling fan as described in any of the above embodiments, wherein the start / stop control circuit controls the start and stop of the cooling fan.

[0030] In one embodiment, the system includes a first cooling fan, a second cooling fan, and an interlocking control loop. The first cooling fan and the second cooling fan are installed in a redundant configuration, and the interlocking control loop controls the switching between the first cooling fan and the second cooling fan.

[0031] The boiler flame detection cooling air start / stop control circuit and boiler flame detection system provided in this application embodiment have at least the following technical effects:

[0032] This utility model provides a start / stop control circuit for boiler flame detection cooling air and a boiler flame detection system. Through a power supply circuit, a remote / local switching circuit, a fan start circuit, and a fan stop circuit, the flame detection cooling air can be started and stopped locally or remotely via the DCS system. This reduces the safety risks for operators starting the flame detection cooling air locally, reduces the workload of personnel operating local equipment, and improves the work efficiency of the production site.

[0033] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0034] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0035] Figure 1 This is a structural block diagram of the start / stop control circuit for the boiler flame detector cooling air in one embodiment of this application;

[0036] Figure 2 This is a circuit diagram of the start / stop control circuit for the boiler flame detector cooling air in one embodiment of this application;

[0037] Figure 3 This is a schematic diagram showing the connection of the status indicator lights of the boiler flame detector cooling air start / stop control circuit in one embodiment of this application. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0039] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0040] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0041] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “a,” “an,” “an,” “the,” and similar words used in this application do not indicate quantity limitation and may indicate singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms “connected,” “linked,” “coupled,” and similar words used in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects are in an "or" relationship. The terms "first," "second," and "third" used in this application are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0042] Because the original control circuits of some units could only start and stop the fans locally, the workload of operators was increased, and certain safety risks were also introduced. The start and stop control circuit designed in this utility model realizes the function of starting the cooling fans remotely through the DCS system. At the same time, in the event of a failure in the start and stop command of the DCS system, the fans can be started and stopped locally, realizing the function of starting and stopping the cooling fans both remotely and locally.

[0043] In a first aspect, embodiments of this application provide a start-stop control circuit for boiler flame detection cooling air, applied in a flame detection system including a cooling fan. The start-stop control circuit includes a power supply circuit, a remote / local switching circuit, a fan start circuit, and a fan stop circuit. (Refer to...) Figure 1The power supply circuit is connected to the remote / local switching circuit, the fan start circuit, and the fan stop circuit, respectively. The output terminal of the remote / local switching circuit is connected to the fan start circuit and the fan stop circuit, respectively. The first control terminal of the fan start circuit is connected to the remote / local switching circuit, the second control terminal is connected to the remote DCS system, and the output terminal is connected to the cooling fan when a remote control signal is received. The first control terminal of the fan stop circuit is connected to the remote / local switching circuit, the second control terminal is connected to the remote DCS system, and the output terminal is connected to the cooling fan.

[0044] In this embodiment, the power supply circuit provides operating voltage to the remote / local switching circuit, the fan start circuit, and the fan stop circuit. When the remote / local switching circuit is in the first state, it outputs a local control signal, and the fan start circuit and the fan stop circuit are in a local control state. When the remote / local switching circuit is in the second state, it outputs a remote control signal, and the fan start circuit and the fan stop circuit are in a remote control state. When the fan start circuit is on, it outputs a fan start signal to control the operation of the cooling fan, and the cooling fan starts. When the fan stop circuit is on, it outputs a fan stop signal to control the shutdown of the cooling fan, and the cooling fan stops. Specifically, when the wind turbine start-up circuit receives a remote control signal, its operation is controlled by a remote start signal issued by the remote DCS system; when the wind turbine start-up circuit receives a local control signal, its operation is controlled by a manual start button on site; when the wind turbine shutdown circuit receives a remote control signal, its operation is controlled by a remote shutdown signal issued by the remote DCS system; when the wind turbine shutdown circuit receives a local control signal, its operation is controlled by a manual shutdown button on site.

[0045] In one specific embodiment, the remote / local switching circuit includes a switching operation switch, which is connected to the first control terminals of the wind turbine start-up circuit and the wind turbine stop-operation circuit, respectively. Specifically, when the switching operation switch is open, the remote / local switching circuit is in a first state, and the wind turbine start-up circuit and the wind turbine stop-operation circuit are in a local control state; when the switching operation switch is closed, the remote / local switching circuit is in a second state, and the wind turbine start-up circuit and the wind turbine stop-operation circuit are in a remote control state.

[0046] In this embodiment, the fan start-up circuit includes a first remote / local switch, a local start-up circuit, a remote start-up circuit, a fan stop switch, and a fan trigger circuit. The local start-up circuit and the remote start-up circuit are connected in parallel between the remote / local switch and the fan stop switch. The fan trigger circuit is located between the fan stop switch and the cooling fan. The control terminal of the first remote / local switch serves as the first control terminal of the fan start-up circuit, and the control terminal of the remote start-up circuit is connected to the remote DCS system. When the fan start-up circuit is in local control mode, the first remote / local switch is connected to the local start-up circuit. When the fan start-up circuit is in remote control mode, the first remote / local switch is connected to the remote start-up circuit. When the local start-up circuit or the remote start-up circuit is activated, the fan trigger circuit is activated and drives the cooling fan to run. Before receiving a fan stop signal, the fan stop switch is in a closed state.

[0047] More specifically, the remote start circuit includes a first electronic switch, and the remote stop circuit includes a second electronic switch. The control terminals of the first and second electronic switches are respectively connected to the remote DCS system. In this embodiment, the first electronic switch is turned on by a remote start signal issued by the remote DCS system, and the second electronic switch is turned on by a remote stop signal issued by the remote DCS system.

[0048] In this embodiment, the fan triggering circuit includes a motor AC contactor and a motor starter, which are connected in series. When the local start circuit or the remote start circuit is turned on, the motor AC contactor is triggered to close, thereby driving the motor starter to run.

[0049] In this embodiment, the wind turbine shutdown circuit includes a second remote / local switch, a local shutdown circuit, and a remote shutdown circuit. The local shutdown circuit and the remote shutdown circuit are connected in parallel between the second remote / local switch and the wind turbine shutdown switch. The control terminal of the second remote / local switch serves as the first control terminal of the wind turbine shutdown circuit, and the control terminal of the remote shutdown circuit is connected to the remote DCS system. When the wind turbine shutdown circuit is in local control mode, the second remote / local switch is connected to the local shutdown circuit; when the wind turbine shutdown circuit is in remote control mode, the remote / local switch is connected to the remote shutdown circuit; when either the local shutdown circuit or the remote shutdown circuit is active, the wind turbine shutdown switch is deactivated.

[0050] More specifically, the local start circuit includes a local manual start switch, and the local stop circuit includes a local manual stop switch. The local manual start switch and the local manual stop switch are installed at the actual application site of the flame detection system.

[0051] In one specific embodiment, the power supply circuit includes a power supply, a power switch, and a power relay, wherein the power relay is connected to the power supply via the power switch. When the power switch is closed, the power supply provides operating voltage to the remote / local switching circuit, the fan start circuit, and the fan stop circuit, and the power relay is closed.

[0052] In a preferred embodiment, the start / stop control circuit includes a power indicator light, a local operation indicator light, a remote operation indicator light, a fan operation indicator switch, a fan operation indicator light, and a fan stop indicator light. The power indicator light is connected to the power supply circuit and illuminates during normal power supply. The local and remote operation indicator lights are respectively connected to the remote / local switching circuit. When the remote / local switching circuit is in a first state, the local operation indicator light illuminates; when the remote / local switching circuit is in a second state, the remote operation indicator light illuminates. The fan operation indicator switch and the fan operation indicator light are connected in series to the fan start circuit. When the fan start circuit is active, the fan operation indicator light illuminates. The fan stop indicator light is connected to the fan stop circuit. When the fan stop circuit is active, the fan stop indicator light illuminates.

[0053] This application addresses the shortcomings of existing technologies in certain units by providing a start-stop control circuit design for a boiler flame detector cooling fan unit. This simplifies the operation process of starting and stopping the boiler flame detector cooling fan at the production site, solves the work intensity and safety risks associated with operating the fan at the work site, and reduces the workload of operators at the production site.

[0054] In actual products, the flame detection cooling fan of a typical flame detection system is designed with redundant configuration of fan A and fan B. After the boiler is ignited, at least one flame detection cooling fan must be running to provide cooling air source for the flame detection system. The start-stop control circuit of this embodiment is designed for the local control loop. This embodiment takes fan A as an example to introduce in detail the start-stop control circuit of the boiler flame detection cooling fan of this application.

[0055] Reference Figure 2The start / stop control circuit of this embodiment includes: a control loop power supply, providing drive power for the entire control circuit; a power switch, serving as the power control switch for the control loop power supply, and also providing a relay for power monitoring; to enable control of the cooling fan from both the DCS side and the local side, a remote / local operation switching function is designed, along with a remote / local function indicator switch; in the local operation function, the cooling fan can be started via a local control button, while in the remote operation function, it can be started via a DCS system start signal; in the manual / automatic start cooling fan circuit, a manual start button, a DCS system start signal, a cooling fan start monitoring relay, and an AC contactor are designed, which drives the motor start circuit to start the cooling fan; in the stop cooling fan circuit, a local stop button, a DCS system stop cooling fan signal, and a cooling fan stop monitoring relay are also designed.

[0056] Figure 3 The control circuit design includes a power status monitoring light, a remote / local switching status indicator, and a cooling fan operation / stop status indicator to facilitate monitoring of the equipment's operating status. (Refer to reference...) Figure 2 and Figure 3 The start / stop control circuit of this embodiment includes: a power switch K1 for the control loop, a power relay KA1 for monitoring the power supply of the control loop, a switching operation switch SA1, a remote / local indicator relay KA2 (i.e., a remote / local switching switch; in this embodiment, the first remote / local switching switch and the second remote / local switching switch share one relay), a local start button SB2 for the cooling fan (i.e., a local manual start switch), a DCS system remote start signal for the cooling fan S2, a cooling fan start contactor J1, a cooling fan motor starter FK1, a cooling fan operation indicator switch KA3, a local stop button SB3 for the cooling fan (i.e., a local manual stop switch), a DCS system remote stop signal for the cooling fan S3, and a fan stop switch KA4.

[0057] During operation, closing the power switch K1 of the cooling fan control circuit closes the power indicator relay KA1, and the power indicator L1 displays a normal status. Switching between remote and local operation permissions is achieved via the switching operation switch SA1. Pressing the switching button closes the remote / local switching relay KA2, and the remote / local indicator lights L2 and L3 display the corresponding status. Under local operation permission, pressing the manual start button SB2 closes the cooling fan motor AC contactor J1, which in turn drives the cooling fan motor starter FK1, thus starting the cooling fan. The cooling fan start indicator relay KA3 closes, and the cooling fan start indicator L4 displays a normal status. Under remote operation permission, the remote DCS system start signal S2 closes, the cooling fan motor AC contactor J1 closes, and the cooling fan motor starter FK1 drives the cooling fan motor starter, starting the cooling fan. During the shutdown of the cooling fan, when the control loop switches to local authority, pressing the shutdown button SB3 will close the shutdown indicator relay KA4, thereby shutting down the cooling fan. When the control loop switches to remote authority from the DCS system, the shutdown signal S3 from the DCS system will close, and the shutdown indicator relay KA4 will close, thereby shutting down the cooling fan.

[0058] Therefore, this application realizes the function of starting and stopping the boiler flame detector cooling fan using remote DCS system signals and local operation buttons. The remote DCS system and local operation permissions can be switched via a switch button in the control loop. Neither remote nor local start / stop will affect the normal operation of the flame detector cooling fan. Simultaneously, monitoring relays and monitoring lights are designed in the start / stop control loop to monitor the power supply status, remote / local operation permission status, fan operating status, and fan shutdown status, which to a certain extent reduces the risk of on-site operation for operators and improves work efficiency.

[0059] The above implementation plan enables local start-stop and remote start-stop functions for the boiler flame detector cooling fan, verifying the feasibility of this solution.

[0060] Secondly, embodiments of this application provide a boiler flame detection system, including a cooling fan and a start / stop control circuit for the boiler flame detection cooling fan as described in any of the above embodiments, wherein the start / stop control circuit controls the start and stop of the cooling fan.

[0061] In a preferred embodiment, the system is provided with a first cooling fan, a second cooling fan, and an interlocking control loop, wherein the first cooling fan and the second cooling fan are installed in a redundant configuration, and the interlocking control loop controls the switching between the first cooling fan and the second cooling fan.

[0062] Specifically, in this embodiment of the boiler flame detection system, the flame detection cooling fans are designed with redundant configurations of fans A and B. After boiler ignition, at least one flame detection cooling fan must be running to provide cooling air for the flame detection system. The start-stop control circuit mentioned in this utility model is designed for the local control loop. This utility model uses fan A as an example to introduce the design content. The design scheme of the start-stop control circuit of fan B is the same as that of fan A. In addition, in case of low cooling air pressure or cooling air failure, an interlocking control circuit is designed on the DCS side to ensure the normal operation of the boiler flame detection cooling air system. The start-stop circuit of the cooling fans described in this utility model does not include the interlocking control circuit on the DCS side.

[0063] In addition, an interlock control circuit for the cooling fan after boiler ignition is designed on the DCS side. When the boiler flame detector cooling air is low or the operating cooling air fails, the backup cooling fan is interlocked to start, ensuring the normal supply of cooling air to the boiler flame detector system and ensuring that the flame detector system does not fail or the boiler shuts down due to the loss of flame detector cooling air.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A start / stop control circuit for boiler flame detector cooling air, characterized in that, In a flame detection system incorporating a cooling fan, the start-stop control circuit includes a power supply circuit, a remote / local switching circuit, a fan start circuit, and a fan stop circuit; wherein, The power supply circuit is connected to the remote / local switching circuit, the fan start circuit, and the fan stop circuit, respectively; the output terminal of the remote / local switching circuit is connected to the fan start circuit and the fan stop circuit, respectively; the first control terminal of the fan start circuit is connected to the remote / local switching circuit, the second control terminal is connected to the remote DCS system, and the output terminal is connected to the cooling fan; the first control terminal of the fan stop circuit is connected to the remote / local switching circuit, the second control terminal is connected to the remote DCS system, and the output terminal is connected to the cooling fan. The power supply circuit is used to provide the operating voltage; when the remote / local switching circuit is in the first state, the fan start circuit and the fan stop circuit are in the local control state; when the remote / local switching circuit is in the second state, the fan start circuit and the fan stop circuit are in the remote control state; when the fan start circuit is on, the cooling fan starts; when the fan stop circuit is on, the cooling fan stops.

2. The start / stop control circuit according to claim 1, characterized in that, The remote / local switching circuit includes a switching operation switch, which is connected to the first control terminals of the wind turbine start-up circuit and the wind turbine shutdown circuit, respectively; wherein... When the switching operation switch is open, the remote / local switching circuit is in the first state, and the wind turbine start-up circuit and the wind turbine stop-down circuit are in the local control state; when the switching operation switch is closed, the remote / local switching circuit is in the second state, and the wind turbine start-up circuit and the wind turbine stop-down circuit are in the remote control state.

3. The start / stop control circuit according to claim 1, characterized in that, The wind turbine start-up circuit includes a first remote / local switching switch, a local start-up circuit, a remote start-up circuit, a wind turbine shutdown switch, and a wind turbine trigger circuit; The local start circuit and the remote start circuit are connected in parallel between the first remote / local switching switch and the fan stop switch. The fan trigger circuit is located between the fan stop switch and the cooling fan. The control terminal of the first remote / local switching switch serves as the first control terminal of the fan start circuit. The control terminal of the remote start circuit is connected to the remote DCS system. Specifically, when the fan starting circuit is in local control mode, the first remote / local switching switch is connected to the local starting circuit; when the fan starting circuit is in remote control mode, the first remote / local switching switch is connected to the remote starting circuit; when the local or remote starting circuit is activated, the fan triggering circuit is activated and drives the cooling fan to run; before receiving a fan shutdown signal, the fan shutdown switch is in the closed state.

4. The start / stop control circuit according to claim 3, characterized in that, The wind turbine shutdown circuit includes a second remote / local switching switch, a local shutdown circuit, and a remote shutdown circuit; The local shutdown circuit and the remote shutdown circuit are connected in parallel between the second remote / local switching switch and the wind turbine shutdown switch. The control terminal of the second remote / local switching switch serves as the first control terminal of the wind turbine shutdown circuit, and the control terminal of the remote shutdown circuit is connected to the remote DCS system. Specifically, when the wind turbine shutdown circuit is in local control mode, the second remote / local switch is connected to the local shutdown circuit; when the wind turbine shutdown circuit is in remote control mode, the remote / local switch is connected to the remote shutdown circuit; when the local shutdown circuit or the remote shutdown circuit is connected, the wind turbine shutdown switch is disconnected.

5. The start / stop control circuit according to claim 3, characterized in that, The fan triggering circuit includes an AC contactor for the motor and a motor starter; wherein... The motor AC contactor and the motor starter are connected in series; when the local starting circuit or the remote starting circuit is turned on, the motor AC contactor is triggered to close, thereby driving the motor starter to run.

6. The start / stop control circuit according to claim 4, characterized in that, The local start circuit includes a local manual start switch, and the local stop circuit includes a local manual stop switch; The local manual start switch and the local manual stop switch are installed in the actual application site of the flame detection system. The remote start circuit includes a first electronic switch, and the remote stop circuit includes a second electronic switch. The control terminals of the first and second electronic switches serve as the second control terminals of the wind turbine start circuit and the wind turbine stop circuit, respectively, and are connected to the remote DCS system. The first electronic switch is turned on by a remote start signal issued by the remote DCS system; the second electronic switch is turned on by a remote stop signal issued by the remote DCS system.

7. The start / stop control circuit according to claim 1, characterized in that, The power supply circuit includes a power supply, a power switch, and a power relay, wherein the power relay is connected to the power supply via the power switch. When the power switch is closed, the power supply provides operating voltage to the remote / local switching circuit, the fan start circuit, and the fan stop circuit, and the power relay is closed.

8. The start / stop control circuit according to claim 7, characterized in that, The start / stop control circuit includes a power indicator light, a local operation indicator light, a remote operation indicator light, a fan operation indicator switch, a fan operation indicator light, and a fan stop indicator light. The power indicator light is connected to the power supply circuit and illuminates when the power supply is normal. The local operation indicator and the remote operation indicator are respectively connected to the remote / local switching circuit. When the remote / local switching circuit is in the first state, the local operation indicator lights up; when the remote / local switching circuit is in the second state, the remote operation indicator lights up. The fan operation indicator switch and the fan operation indicator light are connected in series to the fan start circuit. When the fan start circuit is turned on, the fan operation indicator light will light up. The fan shutdown indicator light is connected to the fan shutdown circuit. When the fan shutdown circuit is turned on, the fan shutdown indicator light will illuminate.

9. A boiler flame detection system, characterized in that, The system includes a cooling fan and a start / stop control circuit for the boiler flame detector cooling air as described in any one of claims 1-8, wherein the start / stop control circuit controls the start and stop of the cooling fan.

10. The boiler flame detection system according to claim 9, characterized in that, The system is equipped with a first cooling fan, a second cooling fan, and an interlocking control loop. The first cooling fan and the second cooling fan are installed in a redundant configuration, and the interlocking control loop controls the switching between the first cooling fan and the second cooling fan.

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