Control System

Abstract

To reduce a time required for start check at starting of control.SOLUTION: A control system includes: relays 12-1, 12-2-1, 12-2-2, 12-3; a combustion control unit 17 for opening and closing the relays 12-1, 12-2-1, 12-2-2, 12-3 and controlling a load 3; and a check execution unit 16 for executing a first check sequence for confirming absence of welding of the relays 12-1, 12-2-1, 12-2-2, 12-3 before starting a series of control sequences by the combustion control unit 17 with respect to a start request, and a second check sequence for confirming absence of welding of the relays 12-1, 12-2-1, 12-2-2, 12-3 before receiving a next start request after stopping of the control sequences. The check execution unit 16 executes only the second check sequence for second and subsequent start requests.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a control system for controlling combustion in a combustion furnace. [Background technology]

[0002] 2. Description of the Related Art Combustion equipment such as combustion furnaces and boilers includes an ignition device and a burner controller as a combustion control system for controlling combustion in the furnace. The ignition device ignites the burner by generating a high voltage of, for example, several kV to several tens of kV in the rod. The burner controller controls the ignition of the burner via the ignition device, monitors the combustion of the burner, and controls the fuel cutoff valve. When igniting the burner, the burner controller controls the fuel cutoff valve, which controls the supply and stop of fuel to the burner, to supply fuel to the burner, and when stopping combustion by the burner, controls the fuel cutoff valve to stop the supply of fuel to the burner.

[0003] When the burner controller receives a start request, it first checks whether the relay inside the burner controller for driving the fuel cutoff valve and the ignition device has welded, and after confirming that the relay is not welded, it starts combustion control. This check is performed to prevent unintended driving of the fuel cutoff valve due to a welded relay, that is, to prevent fuel from leaking out, and this process is called the start check process.

[0004] In addition, the relays are multiplexed so that a single failure does not cause fuel leakage (see Patent Document 1). For example, in the technology disclosed in Patent Document 1, a duplicate relay is provided. However, simply providing two relays is not enough to deal with the situation when an abnormality occurs in both relays. Therefore, the technology disclosed in Patent Document 2 provides three relays to prevent abnormalities such as fuel leakage.

[0005] The technology disclosed in Patent Document 2 will be described below with reference to Figures 5 and 6. Figure 5 is a block diagram showing the configuration of a relay circuit section of a burner controller, and Figure 6 is a flowchart explaining the operation of the burner controller. The relay circuit section of the burner controller 1 is provided with relays 12-1, 12-2 inserted in series into one of the two connection lines 10, 11 connecting the power source 2 and the load 3, and a relay 12-3 inserted in series into the other connection line 11.

[0006] The load 3 may be, for example, a fuel cutoff valve or an ignition device. Each of the relays 12-1 to 12-3 is provided with a detection circuit (not shown) that detects its operation, and feedback information FB1 to FB3 indicating the detection result is output. The process of stop → start check → combustion start → combustion stop is performed in the following order.

[0007] (I) The burner controller 1 starts a start check, for example, when a start-up request is received from an operator (YES in step S100 in FIG. 6).

[0008] (II) At the start of the start check, the burner controller 1 confirms that there is no welding at the contacts of the first relay 12-1 and the third relay 12-3 based on the feedback information FB1 and FB3 (step S101 in FIG. 6).

[0009] (III) When the burner controller 1 has confirmed that the contacts of the first relay 12-1 and the third relay 12-3 are not welded (YES in step S101), it excites the third relay 12-3 to turn on the contacts (step S102 in FIG. 6). The burner controller 1 confirms based on the feedback information FB1 and FB3 that the contacts of the first relay 12-1 are not welded, that the contacts of the third relay 12-3 are in the on state, and that there is no failure (step S103 in FIG. 6).

[0010] (IV) When the burner controller 1 is able to confirm that the contacts of the first relay 12-1 are not welded and that the third relay 12-3 is not broken (YES in step S103), it turns off the contacts of all the relays 12-1 to 12-3 (step S104 in FIG. 6). The burner controller 1 confirms that the contacts of the first relay 12-1 and the third relay 12-3 are not welded based on the feedback information FB1 and FB3 (step S105 in FIG. 6). Note that although a check similar to that in step S101 is performed, the main purpose of step S105 is to prevent fuel leakage in the case where the first relay 12-1 is turned on before confirming that the third relay 12-3 is off and the second relay 12-2 is welded.

[0011] (V) When the burner controller 1 has confirmed that the contacts of the first relay 12-1 and the third relay 12-3 are not welded (YES in step S105), it excites the first relay 12-1 to turn the contact on (step S106 in FIG. 6). The burner controller 1 confirms based on the feedback information FB2 and FB1 that the contacts of the second relay 12-2 are not welded, that the contacts of the first relay 12-1 are in the on state, and that there is no failure (step S107 in FIG. 6).

[0012] (VI) When the burner controller 1 confirms that the contacts of the second relay 12-2 are not welded and that the first relay 12-1 is not broken (YES in step S107), the burner controller 1 completes the start check. After completing the start check, the burner controller 1 starts combustion. Specifically, the burner controller 1 excites the first relay 12-1 and the third relay 12-3 to turn on their respective contacts (step S108 in FIG. 6).

[0013] (VII) Next, the burner controller 1 excites the second relay 12-2 to turn on the contact (FIG. 6, step S109). This causes power to be supplied from the power source 2 to the load 3, and the burner provided in the combustion furnace is ignited.

[0014] If the burner controller 1 detects a problem in at least one of the checks in steps S101, S103, S105, and S107, it stops all processing without proceeding to the next step.

[0015] (VIII) When the burner controller 1 receives a stop command from the operator while the combustion is continuing (YES in step S111 in FIG. 6), the burner controller 1 turns off the contact of the second relay 12-2 (step S112 in FIG. 6). This stops the power supply from the power source 2 to the load 3, and the combustion in the combustion furnace stops (step S113 in FIG. 6).

[0016] (IX) The burner controller 1 turns off the contacts of the first relay 12-1 and the third relay 12-3 (FIG. 6, step S114). In this way, all the relays 12-1 to 12-3 are turned off.

[0017] As described above, by providing three relays, the problems with the technique disclosed in Patent Document 1 can be solved. However, the technology disclosed in Patent Document 2 has the problem that the start check at the start of combustion takes a long time, so the start of combustion is delayed from the timing at which combustion is actually desired, which may affect temperature control. In equipment that starts and stops frequently (for example, every few tens of seconds), the time between stopping and restarting can be as short as about one second, and if the start check takes a long time, the start of combustion will be delayed from the timing at which combustion is actually desired. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] JP 2009-168404 A [Patent Document 2] JP 2011-208922 A Summary of the Invention [Problem to be solved by the invention]

[0019] The present invention has been made to solve the above-mentioned problems, and has an object to provide a control system that can shorten the time required for a start check at the start of control. [Means for solving the problem]

[0020] The control system of the present invention comprises: a first relay inserted in series in a first connection line of two connection lines connecting a power source and a load; a second relay inserted for each load between the first relay and the load; a third relay inserted in series in the second connection line of the two connection lines; a control unit configured to control the load by opening and closing the first, second, and third relays; and a check execution unit configured to execute a first check sequence for confirming that the first, second, and third relays are not welded before a series of control sequences is started by the control unit in response to a startup request from an outside, and a second check sequence for confirming that the first, second, and third relays are not welded after the control sequence is stopped and before receiving a next startup request, wherein the check execution unit executes the first and second check sequences in response to a first startup request and executes only the second check sequence in response to a second or subsequent startup requests.

[0021] In addition, in one configuration example of the control system of the present invention, if a predetermined time or more has passed between the stop of the most recent control sequence and the receipt of a new start-up request, or if a predetermined time or more has passed between the stop of the initial control sequence and the receipt of a new start-up request, the check execution unit regards the new start-up request as an initial start-up request and executes the first check sequence. In one configuration example of the control system of the present invention, the first check sequence includes a first step of confirming that the first and third relays are not welded, a second step of the check execution unit turning on the third relay when it has been confirmed that the first and third relays are not welded and confirming that the first relay is not welded and that the third relay is not at fault, a third step of the check execution unit turning off all relays when it has been confirmed that the first relay is not welded and that the third relay is not at fault, and a third step of the check execution unit turning off all relays when it has been confirmed that the first relay is not welded and that the third relay is not at fault, and a fourth step in which the check execution unit turns the first relay to an on state to confirm that the second relay is not welded and that the first relay is not broken. The second check sequence includes a fifth step in which, after the control unit turns the second relay to an off state and stops the control sequence when the first, second, and third relays are in an on state, the check execution unit turns the third relay to an off state to confirm that the second relay is not welded, and a sixth step in which, when it has been confirmed that the second relay is not welded, the check execution unit turns the first relay to an off state to confirm that the first and third relays are not welded. Effect of the Invention

[0022] According to the present invention, the first and second check sequences are executed for the first startup request, and only the second check sequence is executed for the second or subsequent startup requests, thereby shortening the time required for the start check when control begins. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a block diagram showing the configuration of a combustion control system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a configuration of a burner controller according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a flowchart illustrating the operation of the burner controller according to the embodiment of the present invention. [Figure 4] FIG. 4 is a block diagram showing an example of the configuration of a computer that realizes a burner controller according to an embodiment of the present invention. [Diagram 5] FIG. 5 is a block diagram showing the configuration of a relay circuit section of a conventional burner controller. [Figure 6] FIG. 6 is a flowchart illustrating the operation of a conventional burner controller. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] 1 is a block diagram showing the configuration of a combustion control system according to this embodiment. The combustion control system includes a burner controller 1a, an ignition device 6 that ignites a burner 5 in a combustion furnace 4, a fuel cutoff valve 7 that controls whether or not fuel is supplied to the burner 5, and a flame detector 8 that detects the presence of a flame in the combustion furnace 4.

[0025] The configuration of the ignition device 6 is disclosed in, for example, JP 2016-121845 A, and therefore a detailed description thereof will be omitted. The flame detector 8 detects the presence of a flame by detecting light emitted from the flame inside the combustion furnace 4. However, detection by light is just one example, and flame detection may be performed by other methods.

[0026] 2 is a block diagram showing the configuration of the burner controller 1a. The burner controller 1a includes a first relay 12-1 inserted in series in one of two connection lines 10, 11 connecting the power source 2 and the load 3, second relays 12-2-1, 12-2-2 inserted between the first relay 12-1 and the load 3 for each load, a third relay 12-3 inserted in series in the other connection line 11, a feedback information acquisition unit 13 that acquires feedback information from the relays 12-1 to 12-3, a flame signal acquisition unit 14 that acquires a flame signal from the flame detector 8, a feedback information storage unit 15 that stores the feedback information, a check execution unit 16 that executes checks on the relays 12-1 to 12-3 based on the feedback information, and a combustion control unit 17 that drives the relays 12-1 to 12-3 to ignite the burner 5 and control the opening and closing of the fuel cutoff valve 7.

[0027] In this embodiment, the load 3 includes an ignition device 6 and a fuel cutoff valve 7. In this case, the second relay 12-2 is provided for each load, such as a relay 12-2-1 having one contact terminal connected to the first relay 12-1 and the other contact terminal connected to the ignition device 6, and a relay 12-2-2 having one contact terminal connected to the first relay 12-1 and the other contact terminal connected to the fuel cutoff valve 7.

[0028] The relays 12-1, 12-2-1, 12-2-2, and 12-3 are provided with detection circuits (not shown) for detecting their operations, and feedback information FB1, FB2-1, FB2-2, and FB3 indicating the detection results are output. The process of stop → start check → combustion start → combustion stop is performed in the following order.

[0029] [First run] (I) In a stopped state before the start of combustion, the combustion control section 17 of the burner controller 1a keeps the contacts of all the relays 12-1, 12-2-1, 12-2-2, and 12-3 in the OFF state. The feedback information acquisition unit 13 of the burner controller 1a acquires feedback information FB1, FB2-1, FB2-2, and FB3 from the relays 12-1, 12-2-1, 12-2-2, and 12-3. The acquired feedback information FB1, FB2-1, FB2-2, and FB3 are stored in a feedback information storage unit 15.

[0030] (I) The check execution unit 16 of the burner controller 1a starts a check sequence, for example, when there is a start-up request from an operator (YES in step S200 in FIG. 3).

[0031] (II) At the start of the start check, the check execution unit 16 verifies that there is no welding at the contacts of the first relay 12-1 and the third relay 12-3 based on the feedback information FB1 and FB3 (step S201 in FIG. 3).

[0032] (III) If the check execution unit 16 is able to confirm that the contacts of the first relay 12-1 and the third relay 12-3 are not welded (YES in step S201), it excites the third relay 12-3 to turn on the contacts (step S202 in FIG. 3).The check execution unit 16 confirms, based on the latest feedback information FB1 and FB3, that the contacts of the first relay 12-1 are not welded, that the contacts of the third relay 12-3 are in the on state, and that there is no failure (step S203 in FIG. 3).

[0033] (IV) If the check execution unit 16 is able to confirm that the contacts of the first relay 12-1 are not welded and that the third relay 12-3 is not at fault (YES in step S203), it turns off the contacts of all the relays 12-1, 12-2-1, 12-2-2, and 12-3 (step S204 in FIG. 3).The check execution unit 16 confirms that the contacts of the first relay 12-1 and the third relay 12-3 are not welded based on the latest feedback information FB1 and FB3 (step S205 in FIG. 3).

[0034] (V) When the check execution unit 16 confirms that the contacts of the first relay 12-1 and the third relay 12-3 are not welded (YES in step S205), it excites the first relay 12-1 to turn on the contacts (step S206 in FIG. 3).The check execution unit 16 confirms based on the latest feedback information FB2-1, FB2-2, FB1 that the contacts of the second relays 12-2-1, 12-2-2 are not welded, that the contacts of the first relay 12-1 are in the on state, and that there is no failure (step S207 in FIG. 3).

[0035] (VI) If the check execution unit 16 can confirm that the contacts of the second relays 12-2-1 and 12-2-2 are not welded and that the first relay 12-1 is not at fault (YES in step S207), it completes the first check sequence (steps S202 to S207).

[0036] When the first check sequence is completed, the combustion control unit 17 of the burner controller 1a starts the combustion (control sequence). Specifically, the combustion control unit 17 excites the first relay 12-1 and the third relay 12-3 to turn on the contacts of each relay (step S208 in FIG. 3).

[0037] (VII) Next, the combustion control unit 17 excites the second relays 12-2-1 and 12-2-2 to turn their contacts on (step S209 in FIG. 3). This causes power to be supplied from the power source 2 to the load 3. By turning on the contacts of the second relay 12-2-2 to supply power to the fuel cutoff valve 7, the fuel cutoff valve 7 opens and starts supplying fuel to the burner 5, and by turning on the contacts of the second relay 12-2-1 to supply power to the ignition device 6, the ignition device 6 generates a spark in an ignition electrode rod (not shown) to ignite the burner 5 (step S210 in FIG. 3). The second relays 12-2-1 and 12-2-2 may be turned on simultaneously with the turning on of the first relay 12-1 and the third relay 12-3 in step S208.

[0038] If the check execution unit 16 detects a problem in at least one of the checks in steps S201, S203, S205, and S207 and the result is NO, the check execution unit 16 stops all processing without proceeding to the next step. In step S201, if at least one of the contacts of the first relay 12-1 and the third relay 12-3 is welded, the result is NO. In step S203, if at least one of the contacts of the first relay 12-1 is welded or the contact of the third relay 12-3 is not in the ON state, the result is NO. In step S205, if at least one of the contacts of the first relay 12-1 and the third relay 12-3 is welded, the result is NO. In step S207, if at least one of the contacts of the second relays 12-2-1 and 12-2-2 is welded or the contact of the first relay 12-1 is not in the ON state, the result is NO. Furthermore, the first check sequence is not limited to the procedure described in steps S201 to S207, and may be executed according to another procedure.

[0039] The combustion control unit 17 confirms based on the latest feedback information FB1, FB2-1, FB2-2, FB3 that the contacts of all relays 12-1, 12-2-1, 12-2-2, 12-3 are in the ON state and are not malfunctioning, and maintains the opening operation of the fuel cutoff valve 7 when it confirms the presence of a flame in the combustion furnace 4 from a flame signal acquired from the flame detector 8. In addition, the combustion control unit 17 turns off the contact of the second relay 12-2-1 when a predetermined time has elapsed, thereby stopping the generation of sparks by the ignition device 6.

[0040] (VIII) When the combustion control unit 17 receives a stop command from the operator while the combustion is continuing (YES in step S211 in FIG. 3), for example, it turns off the contact of the second relay 12-2-2 (step S212 in FIG. 3). This stops the power supply from the power source 2 to the fuel cutoff valve 7, closes the fuel cutoff valve 7, stops the fuel supply to the burner 5, and stops the combustion in the combustion furnace 4 (step S213 in FIG. 3).

[0041] (IX) When the control sequence by the combustion control unit 17 is stopped, the check execution unit 16 starts a second check sequence. Specifically, the check execution unit 16 turns off the contact of the third relay 12-3 (step S214 in FIG. 3). The check execution unit 16 checks that the contacts of the second relays 12-2-1 and 12-2-2 are not welded based on the latest feedback information FB2-1 and FB2-2 (step S215 in FIG. 3). The third relay 12-3 may be turned off simultaneously with the second relay 12-2-2 being turned off in step S212.

[0042] (X) If the check execution unit 16 confirms that the contacts of the second relays 12-2-1 and 12-2-2 are not welded (YES in step S215), it turns off the contacts of the first relay 12-1 (step S216 in FIG. 3). In this way, all of the relays 12-1, 12-2-1, 12-2-2, and 12-3 are turned off. The check execution unit 16 confirms that the contacts of the first relay 12-1 and the third relay 12-3 are not welded based on the latest feedback information FB1 and FB3 (step S217 in FIG. 3).

[0043] If the check execution unit 16 can confirm that the contacts of the first relay 12-1 and the third relay 12-3 are not welded (YES in step S217), the second check sequence (steps S214 to S217) is completed. When the second check sequence is completed, the combustion control unit 17 goes into a standby state to wait for the next start-up request.

[0044] Furthermore, if the check execution unit 16 detects a problem in at least one of the checks in steps S215 and S217 and the result is NO, the check execution unit 16 stops all processing without proceeding to the subsequent steps. In step S215, if the contacts of at least one of the second relays 12-2-1 and 12-2-2 are welded, the result is NO. In step S217, if the contacts of at least one of the first relay 12-1 and the third relay 12-3 are welded, the result is NO.

[0045] [Second or subsequent driving] (XI) After the second check sequence is completed, the combustion control unit 17 starts the combustion (control sequence) when, for example, there is a start request from the operator (YES in step S218 in FIG. 3). Specifically, the combustion control unit 17 excites the first relay 12-1 and the third relay 12-3 to turn on the respective contacts (step S219 in FIG. 3).

[0046] (XII) Next, the combustion control unit 17 excites the second relays 12-2-1 and 12-2-2 to turn on the contacts (step S220 in FIG. 3). This causes the fuel cutoff valve 7 to open and start supplying fuel to the burner 5, and the ignition device 6 generates a spark in the ignition electrode rod to ignite the burner 5 (step S210 in FIG. 3). The subsequent processing is as described above.

[0047] As described above, in this embodiment, when the first operation is stopped, the time is longer by the second check sequence of steps S214 to S217, but in the second and subsequent operations, the first check sequence of steps S202 to S207 can be omitted. As a result, in this embodiment, the delay from the start request to the start of combustion in the second and subsequent operations can be made shorter than in the past.

[0048] If a predetermined time (e.g., 24 hours) has elapsed since the most recent control sequence was stopped and a new start request is received, or if a predetermined time has elapsed since the initial control sequence was stopped and a new start request is received, the check execution unit 16 and the combustion control unit 17 consider the new start request to be an initial start request and start processing from step S202, because they need to take into consideration failures and welding of relays 12-1, 12-2-1, 12-2-2, and 12-3 (JIS B8415-3 F.2).

[0049] The feedback information acquisition section 13, the flame signal acquisition section 14, the feedback information storage section 15, the check execution section 16, and the combustion control section 17 of the burner controller 1a described in this embodiment can be realized by a computer equipped with a CPU (Central Processing Unit), a storage device, and an interface, and a program that controls these hardware resources. An example of the configuration of this computer is shown in Figure 4.

[0050] The computer includes a CPU 200, a storage device 201, and an interface device (I / F) 202. Relays 12-1, 12-2-1, 12-2-2, and 12-3, a flame detector 8, and the like are connected to the I / F 202. A program for implementing the control method of the present invention is stored in the storage device 201. The CPU 200 executes the processing described in this embodiment in accordance with the program stored in the storage device 201. [Industrial Applicability]

[0051] The present invention can be applied to facilities including a combustion furnace. [Explanation of symbols]

[0052] 1a...burner controller, 2...power supply, 3...load, 4...combustion furnace, 5...burner, 6...ignition device, 7...fuel shut-off valve, 8...flame detector, 10, 11...connecting lines, 12-1, 12-2, 12-2-1, 12-2-2, 12-3...relays, 13...feedback information acquisition unit, 14...flame signal acquisition unit, 15...feedback information storage unit, 16...check execution unit, 17...combustion control unit.

Claims

1. a first relay inserted in series into a first connection line of two connection lines connecting a power source and a load; a second relay inserted for each load between the first relay and the load; a third relay inserted in series with the second connection line of the two connection lines; a control unit configured to control the load by opening and closing the first, second, and third relays; a check execution unit configured to execute a first check sequence for confirming that the first, second, and third relays are not welded before a series of control sequences is started by the control unit in response to an external startup request, and a second check sequence for confirming that the first, second, and third relays are not welded after the control sequence is stopped and before a next startup request is received, A control system characterized in that the check execution unit executes the first and second check sequences in response to an initial startup request, and executes only the second check sequence in response to a second or subsequent startup request.

2. 2. The control system of claim 1, The control system is characterized in that the check execution unit, when a predetermined time has passed between the stop of the most recent control sequence and the receipt of a new start-up request, or when a predetermined time has passed between the stop of the initial control sequence and the receipt of a new start-up request, regards the new start-up request as an initial start-up request and executes the first check sequence.

3. 3. The control system according to claim 1, The first check sequence includes: a first step of confirming that the first and third relays are not welded; a second step in which, when it is confirmed that the first and third relays are not welded, the check execution unit turns on the third relay to confirm that the first relay is not welded and that the third relay is not at fault; a third step of the check execution unit turning off all relays and confirming that the first and third relays are not welded when it is confirmed that the first relay is not welded and the third relay is not broken; and a fourth step of the check execution unit turning on the first relay when it has been confirmed that the first and third relays are not welded, thereby confirming that the second relay is not welded and that the first relay is not at fault; The second check sequence includes: a fifth step in which, when the first, second and third relays are in an on state, the control unit turns the second relay to an off state to stop the control sequence, and then the check execution unit turns the third relay to an off state to confirm that the second relay is not welded; and a sixth step in which, when it is confirmed that the second relay is not welded, the check execution unit turns off the first relay and confirms that the first and third relays are not welded.

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