Combustion Control System

Abstract

To enable the control of combustion in the state that there is no problem resulting from a communication delay or noise.SOLUTION: A shutoff valve control device 101 includes a contact input 104, and each of a plurality of burner control devices 102a, 102b, 102c, 102d includes a contact output 105. The plurality of contact outputs 105 are loop-connected in strings of beads with a wire 151, ranging from one end side to the other end side of the contact input 104. Each of the plurality of burner control devices 102a, 102b, 102c, 102d detects cutoff of fire during combustion control after the non-ignition / ignition during spark control of a corresponding burner to open the contact output 105 of the own device. The shutoff control device 101 detects the opening of the contact input 104 to set a safety shutoff valve 103 in a closed state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a combustion control system that controls the supply of fuel to a plurality of burners. [Background technology]

[0002] In combustion furnaces such as steel furnaces, heating furnaces, and deodorizing furnaces, the combustion state of the burners installed in the combustion furnace, the temperature inside the furnace, the pressure of the combustion air, the pressure of the fuel supplied to the burners, etc., are monitored and controlled by a combustion control system. One example of a combustion control system is a multi-burner system that controls the combustion of multiple burners installed in a common combustion chamber.

[0003] Some multi-burner systems do not have a shutoff valve for each burner, but are configured to control all of the burners together using a main valve. To control this type of combustion system, a master device that controls the main valve, a slave device that controls the ignition device and flame detector for each burner, and a safety control device that is a higher level than these are used (see Patent Document 1).

[0004] In this system, the master unit and the slave unit perform ignition upon receiving an ignition signal, and the slave unit notifies the master unit whether ignition was successful or not. Therefore, if ignition is not successful, the master unit can close the shutoff valve, allowing safe control. Conventionally, in this system, the master unit and the slave unit are connected by a communication bus, and the above-mentioned mutual exchange of information is realized by this communication bus. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-180863 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above-mentioned technology used communication to send and receive ignition signals and ignition status signals between the master device and slave device, which had issues such as delays due to communication and erroneous notifications due to noise.

[0007] The present invention has been made to solve the above-mentioned problems, and has an object to make it possible to control combustion without problems caused by communication delays and noise. [Means for solving the problem]

[0008] The combustion control system of the present invention comprises a shutoff valve control device that receives a combustion control start command or a combustion control stop command to control the opening and closing of a common safety shutoff valve which collectively switches the supply and shutoff of fuel to a plurality of burners; a plurality of burner control devices provided corresponding to each of the plurality of burners and that receive a combustion control start command or a combustion control stop command to control the ignition of the corresponding burner and monitor the flame state of the corresponding burner after ignition, and if flame failure during combustion control is detected, stop the combustion control of the corresponding burner; a contact input provided in the shutoff valve control device and a plurality of contact outputs provided in each of the plurality of burner control devices, the plurality of contact outputs being loop-connected in a daisy chain from one end of the contact input to the other end, and each of the plurality of burner control devices opens its contact output when it detects either misfire during ignition control of the corresponding burner or flame failure during combustion control after ignition, and the shutoff valve control device detects the opening of the contact input and closes the safety shutoff valve.

[0009] In one configuration example of the above combustion control system, the shutoff valve control device detects a short circuit of the contact input and opens the safety shutoff valve.

[0010] In one configuration example of the above combustion control system, the shutoff valve control device detects whether the contact input is open or short-circuited based on the presence or absence of a voltage or current.

[0011] In one configuration example of the above combustion control system, a main control device is provided that notifies a combustion control start command and a combustion control stop command to the shutoff valve control device and the multiple burner control devices.

[0012] In one configuration example of the above-mentioned combustion control system, each of the multiple burner control devices is connected to a flame detector that detects the presence or absence of a flame in the corresponding burner, and each of the multiple burner control devices determines the presence or absence of a flame in the corresponding burner based on the detection of the presence or absence of a flame by the flame detector connected to the device itself. Effect of the Invention

[0013] As described above, according to the present invention, when a contact input provided on a shutoff valve control device to which a plurality of contact outputs provided on each of a plurality of burner control devices are loop-connected in a daisy chain is opened, the safety shutoff valve is closed, thereby enabling combustion to be controlled without problems due to communication delays or noise. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing a partial configuration of a combustion control system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a configuration diagram showing the configuration of a combustion control system according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a flowchart illustrating an example of the operation of the combustion control system according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A combustion control system according to an embodiment of the present invention will be described below with reference to Fig. 1. This combustion control system includes a shutoff valve control device 101 and multiple burner control devices 102a, 102b, 102c, and 102d. In this example, the system includes four burner control devices 102a, 102b, 102c, and 102d, but the present invention is not limited to this.

[0016] The shutoff valve control device 101 receives a combustion control start command or a combustion control stop command, and controls the opening and closing of a common safety shutoff valve 103 that collectively switches between supplying and cutting off fuel to a plurality of burners.

[0017] A plurality of burner control devices 102a, 102b, 102c, 102d are provided corresponding to each of a plurality of burners, and upon receiving a combustion control start command or a combustion control stop command, control the ignition of the corresponding burner, monitor the flame state of the corresponding burner after ignition, and stop the combustion control of the corresponding burner if a flame failure during combustion control is detected.

[0018] As shown in FIG. 2, this system also includes a main controller 106 that issues a combustion control start command and a combustion control stop command to the shutoff valve controller 101 and a plurality of burner controllers 102a, 102b, 102c, and 102d.

[0019] Each of the burner control devices 102a, 102b, 102c, and 102d controls the ignition of the burners 121a, 121b, 121c, and 121d arranged inside the combustion chamber 120. Ignition devices 122a, 122b, 122c, and 122d are provided corresponding to the burners 121a, 121b, 121c, and 121d. Flame detectors 123a, 123b, 123c, and 123d are provided corresponding to the burners 121a, 121b, 121c, and 121d. The combustion chamber 120 is also provided with devices necessary for combustion control, such as temperature sensors.

[0020] Each of the burner control devices 102a, 102b, 102c, 102d determines the presence or absence of a flame in the corresponding burner 121a, 121b, 121c, 121d based on the presence or absence of a flame detected by the flame detectors 123a, 123b, 123c, 123d connected to the burner control device itself.

[0021] The burners 121a, 121b, 121c, and 121d are devices that heat the inside of the combustion chamber 120. Note that the burners 121a, 121b, 121c, and 121d are, as an example, direct ignition burners that do not have a pilot burner and directly ignite the main burner. The burners 121a, 121b, 121c, and 121d are ignited by ignition devices 122a, 122b, 122c, and 122d provided corresponding to each burner.

[0022] Each of the ignition devices 122a, 122b, 122c, and 122d includes, for example, an ignition transformer and an ignition electrode rod (spark rod) connected to the secondary wiring of the ignition transformer. Each of the ignition devices 122a, 122b, 122c, and 122d ignites the corresponding burner 121a, 121b, 121c, and 121d by generating a high voltage of, for example, several kV to several tens of kV in the spark rod in response to a control signal from the burner control device 102a, 102b, 102c, and 102d.

[0023] Flame detectors 123a, 123b, 123c, and 123d are provided corresponding to burners 121a, 121b, 121c, and 121d, respectively, and are devices for detecting the presence or absence of a flame in the corresponding burner. Each of flame detectors 123a, 123b, 123c, and 123d outputs a flame detection signal indicating the presence or absence of a flame.

[0024] The main fuel flow passage 131 and the branch fuel flow passage 132 are flow passages for supplying fuel to the burners 121a, 121b, 121c, and 121d. Fuel is supplied from the outside to the main fuel flow passage 131, and the fuel is supplied to each of the burners 121a, 121b, 121c, and 121d through the branch fuel flow passages 132 branched into a plurality of passages from the main fuel flow passage 131. A safety shutoff valve 103 is installed in the main fuel flow passage 131, and the branch fuel flow passages 132 are connected to each of the burners 121a, 121b, 121c, and 121d. Here, the fuel can be, for example, gas (gas) or oil (liquid). The type of fuel is not particularly limited.

[0025] The safety shutoff valve 103 switches between supplying and cutting off fuel to the burners 121a, 121b, 121c, and 121d all at once. When the safety shutoff valve 103 is open, fuel is sent from the main fuel passage 131 to the branch fuel passage 132, and fuel is supplied to each of the burners 121a, 121b, 121c, and 121d. When the safety shutoff valve 103 is closed, the inflow of fuel from the main fuel passage 131 to the branch fuel passage 132 is cut off, and fuel is not supplied to the burners 121a, 121b, 121c, and 121d. The safety shutoff valve 103 has a configuration in which two shutoff valves are combined to perform double shutoff, for example, and is arranged at one location in the main fuel passage 131.

[0026] Although not shown, in addition to the branch fuel flow path 132, an air flow path is provided for supplying air to each of the burners 121a, 121b, 121c, and 121d, and air discharged from the blower is supplied to each of the burners 121a, 121b, 121c, and 121d via the air flow path.

[0027] In order to ensure safe operation of the shutoff valve control device 101 and the burner control devices 102a, 102b, 102c, 102d, the main control device 106 outputs instructions to the shutoff valve control device 101 and the burner control devices 102a, 102b, 102c, 102d to permit or prohibit operation of 121a, 121b, 121c, 121d in the combustion chamber 120 based on the combustion states of the burners 121a, 121b, 121c, 121d, the states of each limit interlock (not shown), and burner combustion and shutoff requests from higher-level equipment, and controls the operation of each burner 121a, 121b, 121c, 121d via the shutoff valve control device 101 and the burner control devices 102a, 102b, 102c, 102d.

[0028] Alternatively, the shutoff valve control device 101 monitors the combustion state of burners 121a, 121b, 121c, and 121d, the state of each limit interlock (not shown), etc., and opens the safety shutoff valve 103 only when it confirms that these are in a normal state.

[0029] Examples of the main control device 106 include a limit interlock module for monitoring limit interlocks manufactured based on safety standards for industrial combustion furnaces (e.g., JIS B 8415, General Safety Rules for Industrial Combustion Furnaces), and a programmable logic controller (a so-called safety PLC) configured with dedicated software that complies with the above-mentioned safety rules.

[0030] Here, in the combustion control system according to the embodiment, the shutoff valve control device 101 has a contact input 104, and each of the multiple burner control devices 102a, 102b, 102c, and 102d has a contact output 105. In addition, the multiple contact outputs 105 are loop-connected in a daisy chain from one end side to the other end side of the contact input 104 by wiring 151.

[0031] Each of the burner control devices 102a, 102b, 102c, 102d opens its own contact output 105 when an abnormality is detected in either misfire during combustion control of the corresponding burner or flame failure during combustion control after ignition. The shutoff valve control device 101 also detects an opening of the contact input 104 and closes the safety shutoff valve 103. The shutoff valve control device 101 detects a short circuit in the contact input 104 and opens the safety shutoff valve 103. The shutoff valve control device 101 detects an opening or short circuit in the contact input 104 based on the presence or absence of a voltage or current.

[0032] Next, an example of the operation of the combustion control system will be described with reference to the flowchart of FIG.

[0033] First, in step S101, when an ignition command is received (yes in step S101), in step S102, the burner control devices 102a, 102b, 102c, and 102d check whether or not the corresponding burners 121a, 121b, 121c, and 121d are capable of ignition. When it is confirmed that the burners 121a, 121b, 121c, and 121d are capable of ignition (yes in step S102), in step S103, each of the burner control devices 102a, 102b, 102c, and 102d shorts the contact output 105 to drive the ignition device.

[0034] As a result of the above, contact input 104 is short-circuited, and this state (short-circuit of contact input 104) is detected by shutoff valve control device 101 (yes in step S104), and in step S105, shutoff valve control device 101 opens safety shutoff valve 103. Thereafter, in step S106, burners 121a, 121b, 121c, and 121d are ignited.

[0035] After that, when the burner control devices 102a, 102b, 102c, and 102d detect that any of the burners 121a, 121b, 121c, and 121d is not ignited (not ignited, flame out) by measurements of the flame detectors 123a, 123b, 123c, and 123d (no in step S107), at least one contact output 105 is opened in step S108. The shutoff valve control device 101 that detects this state closes the safety shutoff valve 103 in step S110. Alternatively, when a stop command is output from the main control device 106 (yes in step S109), the shutoff valve control device 101 closes the safety shutoff valve 103 in step S110. As a result, all of the burners 121a, 121b, 121c, and 121d are in an extinguished state.

[0036] As described above, according to the present invention, when a contact input provided on a shutoff valve control device to which a plurality of contact outputs provided on each of a plurality of burner control devices are loop-connected in a daisy chain is opened, the safety shutoff valve is closed, making it possible to control combustion without problems due to communication delays or noise.

[0037] It should be noted that the present invention is not limited to the above-described embodiments, and it is apparent that many modifications and combinations can be made by a person having ordinary knowledge in the art within the technical concept of the present invention. [Explanation of symbols]

[0038] 101...Shut-off valve control device, 102a, 102b, 102c, 102d...burner control device, 103...safety shut-off valve, 104...contact input, 105...contact output, 151...wiring.

Claims

1. a shutoff valve control device that receives a combustion control start command or a combustion control stop command and controls opening and closing of a common safety shutoff valve that collectively switches between supplying and shutting off fuel to a plurality of burners; a plurality of burner control devices provided corresponding to the plurality of burners, each of which receives the combustion control start command or the combustion control stop command to control the ignition of the corresponding burner, monitors the flame state of the corresponding burner after ignition, and stops the combustion control of the corresponding burner when a flame failure during the combustion control is detected; A contact input provided in the shutoff valve control device; a plurality of contact outputs provided in each of the plurality of burner control devices; Equipped with The plurality of contact outputs are connected in a loop from one end side to the other end side of the contact input, Each of the plurality of burner control devices opens a contact output of the burner control device when it detects either a misfire during ignition control of the corresponding burner or a flame cut during combustion control after ignition, The shutoff valve control device detects the opening of the contact input and closes the safety shutoff valve. A combustion control system comprising:

2. 2. The combustion control system according to claim 1, The shutoff valve control device detects a short circuit of the contact input and opens the safety shutoff valve. A combustion control system comprising:

3. 3. The combustion control system according to claim 1, A combustion control system characterized in that the shutoff valve control device detects an open or short circuit of the contact input based on the presence or absence of a voltage or current.

4. The combustion control system according to any one of claims 1 to 3, a main control device that notifies the shutoff valve control device and the plurality of burner control devices of the combustion control start command and the combustion control stop command; A combustion control system comprising:

5. The combustion control system according to any one of claims 1 to 4, Each of the plurality of burner control devices is connected to a flame detector that detects the presence or absence of a flame in the corresponding burner, Each of the plurality of burner control devices determines the presence or absence of a flame in the corresponding burner based on the presence or absence of a flame detected by the flame detector connected to the burner control device. A combustion control system comprising:

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