JP4486903B2 - Combustion control device - Google Patents

Description

  The present invention relates to a combustion control device that controls a combustion device, and more particularly to a technique for checking itself during startup.

  Conventionally, combustion control devices that control combustion devices such as boilers, dryers, and combustion furnaces are known. This combustion control device is provided with a protection relay (combustion safety controller) for monitoring combustion and shutting off safety. The protection relay includes a flame detection relay having a normally open contact, and the contact of the flame detection relay opens and closes according to an electrical signal from a flame detector that detects the flame of the pilot burner and the main burner. The flame detector detects the presence or absence of a flame, converts it into an electrical signal, and sends it to the protection relay. This electric signal is called a flame detection signal or a flame current.

  While the pilot burner or the main burner is burning, a flame current flows from the flame detector to the protection relay, and the contact of the flame detection relay is closed. As a result, power is supplied to the drive portion of the safety cutoff valve, the safety cutoff valve is held open, and fuel is supplied to the combustion device. On the other hand, when the combustion of the pilot burner and the main burner is stopped and the flame is extinguished, the flame current flowing from the flame detector to the protection relay is stopped and the contact of the flame detection relay is opened. As a result, the supply of power to the drive unit of the safety cutoff valve is stopped, the safety cutoff valve is closed, and the fuel supply to the combustion device is stopped.

  Such a protection relay has a predetermined sequence (operation procedure) for safely starting, operating, and stopping the combustion apparatus. The protection relay is, for example, the presence or absence of a self-failure or the presence or absence of an abnormality in the flame detector (presence or absence of a pseudo flame signal that is equivalent to the flame detection signal), etc., before the ignition operation at the time of starting the combustion device. Self-inspect. This self-inspection is performed by supplying an activation signal to the protection relay and supplying current to each part to check whether it operates normally. This series of self-inspection before startup is called “start check”. In the start check, if it is confirmed that the combustion apparatus is normal, the combustion apparatus is started. If there is any abnormality, the safety switch is activated to prevent the combustion apparatus from starting.

  The safety switch is made of, for example, bimetal, etc. When the energization amount at the start check becomes abnormally large, the safety switch is thermally deformed, mechanically closes the safety shut-off valve, and locks out the protect relay. Lockout means that after a safety switch is activated, it cannot be activated again unless it is reset. In the conventional combustion control device, after the safety switch is operated, the safety switch is manually reset when it is ensured that the operator is safe.

As a related technique, Patent Document 1 discloses a combustion control device that can diagnose and diagnose a spark rod abnormality and an ignition transformer abnormality based on the measured primary current and flame current of the ignition transformer. ing. This combustion control device includes an ignition transformer that supplies an ignition current to a spark rod facing the pilot burner of the combustion device, and a flame detector that detects a flame signal of the pilot burner, and at the spark check timing before the start of combustion. Based on the primary current supplied to the ignition transformer and the flame current based on the detection output of the flame detector at the spark check timing, the microprocessor is caused to detect abnormality of the spark rod or the ignition transformer.
JP-A-8-145345

  As described above, since the mechanically operated safety switch is employed in the conventional combustion control device, the protect relay itself becomes large, and when the safety switch is activated, the operator goes to the site and manually operates. It is necessary to perform the reset operation. Therefore, there is a demand for a protective relay that can be miniaturized so that even if the safety switch is activated, the operator does not have to go to the site and manually perform a reset operation.

  Further, in the conventional protect relay, even if there is an abnormality such as a failure of the relay or the like before the start check is completed, the power supply is stopped by the operation of the safety switch, so that an output indicating that it is abnormal cannot be obtained. Furthermore, since a circuit for detecting an abnormality such as a pseudo flame or a UV abnormality during the start check is not specially provided, there is a problem that such an abnormality cannot be determined before the start check is completed.

  The present invention has been made to meet the above-described demand and to solve the above-described problems, and even before the start check that is performed prior to the ignition is completed before the combustion apparatus enters the ignition operation. An object of the present invention is to provide a combustion control device that can be miniaturized and that can perform various self-inspections to know the presence or absence of abnormality.

In order to achieve the above object, a combustion control apparatus according to a first invention
A start-up inspection relay that contacts the first contact when the voltage applied to the coil is less than the operating voltage, and contacts the second contact when the voltage exceeds the operating voltage;
A capacitor connected to the first contact of the start-up inspection relay and charged when there is no fault;
A first switch element connected in series to a coil of the start-up inspection relay arranged to form a discharge path of the capacitor;
By turning off the first switch element in accordance with a start signal for starting a start check that checks itself before starting the combustion device, the voltage applied to the coil of the start check relay is made less than the operating voltage, The capacitor is charged from the power source via the first contact of the start inspection relay, and after a predetermined time elapses, the first switch element is turned on according to the start signal to discharge the capacitor and thereby the start inspection relay. A combustion control device comprising control means for activating a start check completion signal by switching the contact point of the start inspection relay to the second contact point by setting the voltage applied to the coil to an operating voltage or higher ,
The control means includes
An alarm relay that outputs an alarm signal when the contact is closed;
A second switch element connected in series to the coil of the alarm relay and flowing a current of a magnitude that does not close the contact of the alarm relay when the alarm relay is turned on according to the activation signal;
A low level voltage generated by turning on the second switch element or a high level voltage generated by turning off the second switch element is compared with a predetermined reference voltage, and the voltage is a reference voltage. Comparator that turns off the first switch element when smaller than that, and turns on the first switch element when not smaller
It is characterized by comprising a.

  In this way, if there is no failure, the capacitor is charged according to the start signal, and then the capacitor is discharged after a predetermined time has passed to switch the contact of the start-up inspection relay from the first contact to the second contact. Although the completion signal is activated, if there is a failure, the capacitor is not charged. Therefore, the capacitor is not discharged even after a predetermined time has elapsed, and the contact of the start-up inspection relay is not switched from the first contact to the second contact. Therefore, the start check completion signal is not activated, and the start-up sequence by the combustion control device does not proceed to the next stage. Thereby, safety is ensured.

As described above, even if the second switch element is turned on due to some failure, the first switch element remains on unless a low level voltage is generated. As a result, since the capacitor is not charged, the capacitor is not discharged even after a predetermined time has elapsed, and the contact of the start-up inspection relay is not switched from the first contact to the second contact. Therefore, the start check completion signal is not activated, and the start-up sequence by the combustion control device does not proceed to the next stage. Thereby, safety is ensured.

Further, a combustion control device according to a second invention is the combustion control device according to the first invention,
A first flame detection relay provided between a first contact of the start-up inspection relay and the capacitor, wherein the contact is opened when a flame is detected;
An ignition trial relay that outputs an ignition completion signal indicating that ignition is normally completed by connecting a coil to the second contact of the start inspection relay and closing the contact;
A second flame detection relay is provided between the coil of the ignition trial relay and the ground, and a contact is closed when a flame is detected.

  As a result, if a flame is detected before the start check is completed, the capacitor is not charged. Therefore, the capacitor is not discharged even after a predetermined time has elapsed, and the contact of the start inspection relay is not switched from the first contact to the second contact. Therefore, an abnormality such as a pseudo flame or a UV abnormality can be determined before the start check is completed. Further, when a flame is detected after completion of the start check, the start check completion signal becomes active. However, if no flame is detected, the start check completion signal does not become active. Therefore, the start-up sequence by the combustion control device does not proceed to the next stage, thereby ensuring safety.

Further, a combustion control device according to a third invention is the combustion control device according to the first invention,
The timing of the predetermined time is started after the first switch element is turned off by the activation signal, and power is supplied to the coil of the alarm relay when the predetermined time elapses, thereby closing the contact. And a timer for outputting an alarm signal.

  As a result, even before the start check is completed, an alarm signal is output if the start check completion signal is not output even after a predetermined time has elapsed after the start signal is input. Therefore, it is possible to notify the user that some failure exists even before the start check is completed.

  According to the combustion control device of the present invention, it is possible to provide a combustion control device that can be miniaturized and that can perform various self-inspections to know the presence or absence of abnormality even before the start check is completed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a circuit diagram showing a configuration of a combustion control apparatus according to an embodiment of the present invention. This combustion control device includes resistors R1 to R6, a capacitor C1, transistors Q1 and Q2, a comparator U1, a reset switch S1, a start inspection relay K1, an alarm relay K2set, an alarm reset relay K2reset, a first flame detection relay K3a, and a second flame. It comprises a detection relay K3b, an ignition trial relay K4, an ignition circuit 10, and a timer 20.

  The transistor Q1 corresponds to the first switch element of the present invention. The collector of the transistor Q1 is connected to one terminal of the coil of the start inspection relay K1, the emitter is grounded, and the base is connected to the output terminal of the comparator U1. The other terminal of the coil of the start inspection relay K1 is connected to one terminal of each of the capacitor C1, the resistor R1, and the resistor R2. The other terminal of the capacitor C1 is grounded. The other terminal of the resistor R1 is connected to a contact terminal b of the first flame detection relay K3a.

  The first flame detection relay K3a and the second flame detection relay K3b are constituted by two-pole relays having a transfer contact (c contact) structure, and these contacts are interlocked by driving one coil (not shown). Works. Specifically, the contact of the first flame detection relay K3a contacts the terminal b when there is no flame detection signal from a flame detector (not shown) (when no frame current flows through the coil), and the flame detection signal is When present (when a frame current flows through the coil), it contacts the terminal a which is an open end. In this specification, the contact of the first flame detection relay K3a with the terminal b is referred to as “the contact is closed”, and the contact with the terminal a which is an open end is “the contact is opened”. Call it. The common terminal c of the contact of the first flame detection relay K3a is connected to the terminal b of the contact of the start inspection relay K1.

  Similarly, the contact of the second flame detection relay K3b contacts the terminal b which is an open end when there is no flame detection signal from the flame detector, and contacts the terminal a when there is a flame detection signal. In this specification, the contact of the second flame detection relay K3b with the terminal b is referred to as “the contact is closed”, and the contact with the terminal a which is an open end is “the contact is opened”. Call it. The common terminal c of the contact point of the second flame detection relay K3b is grounded.

  The start inspection relay K1 has a transfer contact (c contact) structure. When the operating voltage (voltage required to turn on the contact) is not applied to the coil of the start inspection relay K1, the contact of the start inspection relay K1 contacts the terminal b, and the operation voltage is applied to the coil of the start inspection relay K1. When it is done, it contacts the terminal a. The terminal b of the start inspection relay K1 corresponds to the first contact of the present invention, and the terminal b corresponds to the second contact. The common terminal c of the contact of the start inspection relay K1 is connected to the power supply VDD. A signal flowing to the terminal a of the contact point of the start inspection relay K1 is referred to as a “start check completion signal”.

  The contact a of the start inspection relay K1 is connected to the non-inverting input terminal (+) of the comparator U1 and one terminal of the ignition trial relay K4. The reference voltage Vref is supplied to the inverting input terminal (−) of the comparator U1. As described above, the output terminal of the comparator U1 is connected to the base of the transistor Q1. The output terminal of the comparator U1 is pulled up to the power supply VDD via the resistor R6.

  A resistor R2 is connected between the non-inverting input terminal (+) of the comparator U1 and the other terminal of the coil of the start inspection relay K1 (a connection point between the coil of the start inspection relay K1 and the resistor R1). The non-inverting input terminal (+) of the comparator U1 is connected to the power supply VDD via the resistor R3 and to one terminal of the resistor R4. The other terminal of the resistor R4 is connected to one terminal of the coil of the alarm relay K2set, and the other terminal of this coil is connected to the collector of the transistor Q2. A contact (not shown) of the alarm relay K2set is closed when a predetermined operating voltage is applied to the coil of the alarm relay K2set to generate an alarm signal.

  The transistor Q2 corresponds to the second switch element of the present invention. The emitter of the transistor Q2 is grounded, and the base is connected to the terminal a of the contact point of the second flame detection relay K3b. The other terminal of the coil of the ignition trial relay K4, one terminal of the resistor R5, and the ignition circuit 10 are connected to the base of the transistor Q2. A contact (not shown) of the ignition trial relay K4 is closed when a predetermined operating voltage is applied to the coil of the ignition trial relay K4, and an “ignition completion signal” is generated. The other terminal of the resistor R5 is connected to the power supply VDD via the coil of the alarm reset relay K2reset and grounded via the reset switch S1.

  The contact (not shown) of the alarm reset relay K2reset is activated by applying a predetermined operating voltage to the coil of the alarm reset relay K2reset to stop the generation of the alarm signal. The reset switch S1 is a switch that is turned on when pressed. When the reset switch S1 is turned on, a current flows through the alarm reset relay K2reset and a predetermined operating voltage is applied. Therefore, the user can stop the generation of the alarm signal by pressing the reset switch S1.

  The ignition circuit 10 generates a start signal that defines the start of the start check and the start of the ignition trial as shown in FIG. The start signal generated by the ignition circuit 10 is supplied to the base of the transistor Q2.

  The timer 20 is connected to the contact point of the start inspection relay K1 even when the time from when the ignition signal is generated by the ignition circuit 10 until the completion of the ignition trial (time T0 to time T2 shown in FIG. 2) elapses. When the state of contact with b does not switch to the state of contact with terminal a, power supply VDD is supplied to the connection point between the coil of alarm relay K2set and resistor R4. As a result, a current flows through the coil of the alarm relay K2set, and an alarm signal is generated.

  Next, the operation of the combustion control apparatus according to the embodiment of the present invention configured as described above will be described with reference to the timing chart shown in FIG.

  First, normal operation will be described. When an ignition signal that rises at time T0 as shown in FIG. 2A is output from the ignition circuit 10, a start check is started. That is, when the activation signal becomes H level, the transistor Q2 is turned on. As a result, a current flows from the power supply VDD to the ground via the resistor R3, the resistor R4, the coil of the alarm relay K2set, and the transistor Q2 sequentially. At this time, the current flowing through the coil of the alarm relay K2set is limited by the resistors R3 and R4 so that the contact of the alarm relay K2set is not closed.

  As shown in FIG. 2B, the non-inverting input terminal (+) of the comparator U1 is caused by the current flowing from the power source VDD to the ground through the resistor R3, the resistor R4, the coil of the alarm relay K2set and the transistor Q2 in sequence. In addition, a low level voltage (hereinafter referred to as “L level”) obtained by dividing the voltage of the power source VDD by the resistors R3 and R4 is applied. As a result, the voltage applied to the non-inverting input terminal (+) of the comparator U1 is lower than the reference voltage Vref applied to the inverting input terminal (−), so that the comparator U1 is shown in FIG. Thus, an L level signal is output. By applying this L level signal to the base of the transistor Q1, the transistor Q1 is turned off as shown in FIG. As a result, current flows into the capacitor C1 from the power supply VDD through the contact of the start inspection relay K1, the contact of the first flame detection relay K3a, and the resistor R1 in sequence, and the capacitor C1 is gradually charged.

  When a predetermined time elapses from this state and reaches time T1, the ignition circuit 10 changes the activation signal to L level as shown in FIG. The time from time T0 to time T1 is determined in advance so as to be sufficient for charging the capacitor C1. When the activation signal changes to the L level, an L level signal is given to the base of the transistor Q2, so that the transistor Q2 is turned off. As a result, the current flowing from the power source VDD to the ground via the resistor R3, the resistor R4, the coil of the alarm relay K2set and the transistor Q2 in sequence is cut off, and the non-inverting input terminal (+) of the comparator U1 is connected to FIG. As shown in (b), an H level voltage is applied. As a result, the voltage applied to the non-inverting input terminal (+) of the comparator U1 becomes higher than the reference voltage Vref applied to the inverting input terminal (−), and as shown in FIG. 2 (c), the comparator U1. Outputs an H level signal.

  When the H level signal output from the comparator U1 is applied to the base of the transistor Q1, the transistor Q1 is turned on. As a result, the electric charge charged in the capacitor C1 is discharged via the coil of the start inspection relay K1 and the transistor Q1, and a current flows through the coil of the start inspection relay K1. Due to the current flowing through the coil of the start / inspection relay K1, a voltage higher than the operating voltage of the coil is applied, and the contact of the start / inspection relay K1 is switched from being in contact with the terminal b to being in contact with the terminal a. As a result, as shown in FIG. 2E, the start check completion signal is activated (H level), and the start check is completed.

  When the start check is completed, an ignition trial is then executed. The period of the ignition trial is a period from time T1 to time T2 defined by the activation signal, and the pilot burner is ignited during this period. As shown in FIG. 2 (f), if an H level flame detection signal indicating that a flame has been detected is output from the flame detector (not shown) during this ignition trial period, the first flame detection relay K3a and the first flame detection relay K3a Each contact of the two flame detection relay K3b is switched from the state in contact with the terminal b to the state in contact with the terminal a. As a result, the terminal a of the contact point of the second flame detection relay K3b is grounded, and its potential changes from the H level to the L level as shown in FIG. 2 (h).

  As a result, a current flows from the power supply VDD to the ground via the contact of the start inspection relay K1, the coil of the ignition trial relay K4, and the second flame detection relay K3b in sequence. As a result, the contact (not shown) of the ignition trial relay K4 is activated, and as shown in FIG. 2G, the ignition completion signal is activated (H level) in synchronization with the time T2 of the start signal by the control circuit (not shown). ). With the above operation, the ignition trial is completed, and the start-up sequence by the combustion control device proceeds to the next stage.

  If the flame detection signal does not become H level during the ignition trial period, the ignition circuit 10 outputs a signal that rises at time T2 as shown in FIG. As a result, the transistor Q2 is turned on, and a current flows from the power supply VDD to the ground through the resistor R3, the resistor R4, the coil of the alarm relay K2set, and the transistor Q2. As a result, the output of the comparator U1 becomes L level, and the transistor Q1 is turned off. As a result, since the current flowing in the coil of the start inspection relay K1 is stopped, the contact of the start inspection relay K1 returns from the state in contact with the terminal a to the state in contact with the terminal b, and is in the same state as the initial state. Become. In this case, since the ignition completion signal is not activated, the activation sequence by the combustion control device does not proceed to the next stage, and activation of the combustion device is suppressed. In this case, since the contact of the start inspection relay K1 is not switched from the state in contact with the terminal b to the state in contact with the terminal a before the ignition trial is completed, the coil of the alarm relay K2set from the timer 20 is not switched. When the power supply VDD is supplied to the connection point between the resistor R4 and the resistor R4, the contact of the alarm relay K2set is activated to generate an alarm signal.

  Next, the operation at the time of abnormality will be described. In the combustion control apparatus according to the embodiment of the present invention, it is possible to prevent the start check completion signal from becoming active because the contact of the start inspection relay K1 is in contact with the terminal a regardless of any failure. Thus, safety is ensured based on the idea of preventing the start-up sequence by the combustion control device from proceeding to the next stage.

  First, a case where there is a failure in the resistor R3 or the resistor R4 will be described. Consider a case where the resistor R4 has an open failure. In this case, the non-inverting input terminal (+) of the comparator U1 is supplied with an H level signal from the power supply VDD via the resistor R3. Therefore, the comparator U1 outputs an H level signal, and the transistor Q1 is turned on. As a result, a current flows from the power supply VDD to the ground through the contact of the start inspection relay K1, the contact of the first flame detection relay K3a, the resistor R1, the coil of the start inspection relay K1, and the transistor Q1 in order. When an operating voltage is applied to the coil of the start inspection relay K1 by this current, the contact of the start inspection relay K1 is turned on, and the start check completion signal is activated.

  Therefore, the current flowing from the power source VDD to the ground via the contact of the start inspection relay K1, the contact of the first flame detection relay K3a, the resistor R1, the coil of the start inspection relay K1 and the transistor Q1 is limited by the resistor R1 to start the operation. The resistance value of the resistor R1 is set so that the voltage applied to the coil of the inspection relay K1 is equal to or lower than the operating voltage. In other words, the contact point of the start inspection relay K1 changes to a state in which it is brought into contact with the terminal a only when a voltage resulting from the discharge of the capacitor C1 is applied to the coil. Therefore, even if the resistor R4 is open-failed, the contact of the start inspection relay K1 does not change to a state in which it is in contact with the terminal a. Therefore, the start check completion signal is not activated, and the start sequence by the combustion control device is Does not proceed to the next stage.

  When the resistor R3 has an open failure, the non-inverting input terminal (+) of the comparator U1 is connected to the contact of the start inspection relay K1, the contact of the first flame detection relay K3a, the resistor R1 and the resistor R2 from the power source VDD. H level signal is supplied via. Therefore, even if the resistor R3 has an open failure, the contact of the start inspection relay K1 does not change to a state in which the resistor R4 is in contact with the terminal a by an operation similar to that in the case where the resistor R4 has an open failure. The activation sequence by the combustion control device does not proceed to the next stage.

  Further, when at least one of the resistor R3 and the resistor R4 is short-circuited, the current flowing through the coil of the alarm relay K2set cannot be limited during the start check period. As a result, since the voltage applied to the coil of the alarm relay K2set is equal to or higher than the operating voltage, a contact (not shown) of the alarm relay K2set is closed and an alarm signal is generated. Therefore, the user can know the failure even before the start check is completed.

  In this case, if the failure mode is such that the output of the comparator U1 is always at the H level, the transistor Q1 is always on, so that the capacitor C1 is not charged. On the other hand, if the failure mode is such that the output of the comparator U1 is always at the L level, the transistor Q1 is always off, so that no current flows through the coil of the start inspection relay K1. Accordingly, in any case, the contact point of the start inspection relay K1 does not change to the state in which it is in contact with the terminal a. Therefore, the start check completion signal is not activated, and the start sequence by the combustion control device is as follows. Don't go to the stage.

  Next, the operation when a failure occurs in which the capacitor C1 is not charged will be described. This may be due to a short circuit failure of the transistor Q1. In this case, since a discharge current does not flow through the coil of the start inspection relay K1, the contact of the start inspection relay K1 does not change to a state where it is in contact with the terminal a. Further, even when the coil of the start / inspection relay K1 is disconnected, no discharge current flows through the coil of the start / inspection relay K1, so that the contact of the start / inspection relay K1 does not change to a state of being in contact with the terminal a. . Therefore, the start check completion signal is not activated, and the start-up sequence by the combustion control device does not proceed to the next stage.

  Next, the operation when the timer 20 fails will be described. If the power supply VDD is supplied to the connection point between the coil of the alarm relay K2set and the resistor R4 due to the failure of the timer 20, the timer 20, the resistor R4, the resistor R2, the coil of the start inspection relay K1 from the power supply VDD and There is a possibility that a current flows to the ground via the transistor Q1 sequentially. In this case, when the operating voltage necessary to turn on the contact is applied to the coil of the start inspection relay K1, the contact of the start inspection relay K1 is turned on and the timer 20 is out of order. The start check completion signal is activated.

  Therefore, the resistance values of the resistors R2 and R4 are determined so as to satisfy the following formula (1). Thereby, even if the timer 20 breaks down, the contact of the start check relay K1 is not turned on, so the start check completion signal is not activated, and the start-up sequence by the combustion control device does not proceed to the next stage. Thereby, safety is ensured.

次に、スタートチェック完了前に、擬似火炎やＵＶ異常が発生した場合の動作を説明する。スタートチェック完了前に、擬似火炎やＵＶ異常が発生すると、第１火炎検出リレーＫ３ａおよび第２火炎検出リレーＫ３ｂの各接点は、端子ｂに接触された状態から端子ａに接触される状態に変化するので、コンデンサＣ１に電荷がチャージされることはない。従って、始動点検リレーＫ１の接点は、オンしないので、スタートチェック完了信号がアクティブにされることはなく、燃焼制御装置による起動シーケンスは次の段階に進まない。これにより、安全性が確保されている。

Next, the operation when a pseudo flame or UV abnormality occurs before the start check is completed will be described. If a pseudo flame or UV abnormality occurs before the start check is completed, the contacts of the first flame detection relay K3a and the second flame detection relay K3b change from being in contact with the terminal b to being in contact with the terminal a. Therefore, the capacitor C1 is not charged. Accordingly, since the contact of the start inspection relay K1 is not turned on, the start check completion signal is not activated, and the start-up sequence by the combustion control device does not proceed to the next stage. Thereby, safety is ensured.

  As described above, according to the combustion control device according to the embodiment of the present invention, the portion that functions as a safety switch is configured by an electric circuit, so that the protect relay can be reduced in size, and thus the combustion control device is It can be downsized. Since it is not a mechanical safety switch, it can be configured such that when the safety switch is activated, the reset operation is electrically performed remotely. According to this configuration, there is no need for the operator to go to the site and manually perform a reset operation.

  Also, even if an abnormality such as a failure of the relay is detected before the start check is completed, the power supply is not stopped, so that an output indicating an abnormality is obtained even before the start check is completed. be able to. Further, even if a pseudo flame or UV abnormality occurs before the start check is completed, it can be determined and the start sequence by the combustion control device can be prevented from proceeding to the next stage.

It is a block diagram which shows the circuit structure of the combustion control apparatus which concerns on embodiment of this invention. It is a timing chart which shows operation | movement of the combustion control apparatus which concerns on embodiment of this invention.

Explanation of symbols

R1-R6 Resistor C1 Capacitor Q1, Q2 Transistor U1 Comparator S1 Reset switch K1 Start check relay K2set Alarm relay K2reset Alarm reset relay K3a First flame detection relay K3b Second flame detection relay K4 Ignition trial relay 10 Ignition circuit 20 Timer

Claims (3)

A start-up inspection relay that contacts the first contact when the voltage applied to the coil is less than the operating voltage, and contacts the second contact when the voltage exceeds the operating voltage;
A capacitor connected to the first contact of the start-up inspection relay and charged when there is no fault;
A first switch element connected in series to a coil of the start-up inspection relay arranged to form a discharge path of the capacitor;
By turning off the first switch element in accordance with a start signal for starting a start check that checks itself before starting the combustion device, the voltage applied to the coil of the start check relay is made less than the operating voltage, The capacitor is charged from the power source via the first contact of the start inspection relay, and after a predetermined time elapses, the first switch element is turned on according to the start signal to discharge the capacitor and thereby the start inspection relay. A combustion control device comprising control means for activating a start check completion signal by switching the contact point of the start inspection relay to the second contact point by setting the voltage applied to the coil to an operating voltage or higher ,
The control means includes
An alarm relay that outputs an alarm signal when the contact is closed;
A second switch element connected in series to the coil of the alarm relay and flowing a current of a magnitude that does not close the contact of the alarm relay when the alarm relay is turned on according to the activation signal;
A low level voltage generated by turning on the second switch element or a high level voltage generated by turning off the second switch element is compared with a predetermined reference voltage, and the voltage is a reference voltage. Comparator that turns off the first switch element when smaller than that, and turns on the first switch element when not smaller
Combustion control apparatus characterized by comprising a. A first flame detection relay provided between a first contact of the start-up inspection relay and the capacitor, wherein the contact is opened when a flame is detected;
An ignition trial relay that outputs an ignition completion signal indicating that ignition is normally completed by connecting a coil to the second contact of the start inspection relay and closing the contact;
A second flame detection relay that is provided between the coil of the ignition trial relay and the ground and closes the contact when a flame is detected.
The combustion control apparatus according to claim 1, further comprising: The timing of the predetermined time is started after the first switch element is turned off by the activation signal, and power is supplied to the coil of the alarm relay when the predetermined time elapses, thereby closing the contact. The combustion control apparatus according to claim 1, further comprising a timer that outputs a warning signal .

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