JP5489832B2 - Gas combustion equipment - Google Patents

Description

  The present invention relates to a gas combustion apparatus having a function of monitoring a combustion state of a burner with a thermocouple.

  Conventionally, in a combustion apparatus equipped with a thermocouple provided in the vicinity of the burner to detect the combustion state of the burner, a configuration has been proposed in which the presence or absence of a thermocouple amplifier failure is detected during combustion of the burner. (For example, refer to Patent Document 1).

  In the combustion apparatus described in Patent Document 1, when the input to the amplifier is switched from the thermocouple input to the reference voltage during combustion of the burner, and the output voltage of the amplifier with respect to the reference voltage input is not within the predetermined range. When the cycle of the output voltage of the amplifier is different from the cycle of switching the input to the amplifier, it is determined that the thermocouple amplifier has failed.

JP 2004-93047 A

  The thermocouple provided in the combustion device is used to detect the burner misfire, but when starting the burner combustion operation, it is guaranteed that the misfire of the burner is normally detected by the thermocouple. desirable. And since the electromotive force of a thermocouple does not fall to a misfire determination level during combustion of a burner, it is necessary to perform the determination of misfire detection by a thermocouple when the burner is in a fire extinguishing state.

  Therefore, using a battery as a power source, power supply from the battery to the control circuit is started in response to the user turning on the ignition / extinguishing switch, and from the battery to the control circuit in response to the turning off of the ignition / extinguishing switch. In a combustion apparatus having a specification in which power supply is cut off, it is conceivable to determine whether or not to detect a misfire of a thermocouple from when the ignition switch is turned on until the ignition process is executed.

  However, since the response speed of thermocouples is slow, the burner ignition / extinguishing operation is frequently performed and the burner combustion operation is performed intermittently. When the ignition switch is turned on In addition, the electromotive force of the thermocouple may not have decreased to the misfire determination level. In this case, the presence or absence of abnormality of the thermocouple cannot be detected.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a combustion apparatus that operates with power supplied from a battery and can detect more reliably the presence or absence of abnormality in a thermocouple for burner misfire determination.

  The present invention has been made to achieve the above object, and includes a burner, a thermocouple for detecting the combustion state of the burner, an operation switch for instructing ignition and extinguishing of the burner, a battery, and switching. An element, a drive circuit for bringing the switching element into a conductive state when the operation switch is turned on, and the battery connected via the switching element and operated by electric power supplied from the battery via the switching element And a combustion circuit comprising a control circuit for controlling the operation of the burner.

When the switching circuit is turned on by the drive circuit and the power supply from the battery is started, the control circuit turns on the switching element regardless of whether the operation switch is on or off. And a power supply holding unit to be held, and when the combustion operation of the burner is started in response to an ignition operation by the operation switch, and when a fire extinguishing operation is performed by the operation switch during the combustion operation of the burner, and by the thermocouple A combustion operation unit that terminates the combustion operation of the burner when the misfire of the burner is detected, and an ignition operation by the operation switch is not performed from the end of the combustion operation of the burner by the combustion operation unit. When a predetermined time has elapsed, a thermocouple abnormality detection unit that detects presence or absence of abnormality of the thermocouple, and the thermocouple abnormality detection unit A power supply cutoff unit that releases the holding state of the switching element by the power supply holding unit and shuts off the switching element after the detection of the presence or absence of abnormality of the couple is completed. And

  According to the present invention, when the operation switch is turned on and the switching element is turned on by the drive circuit, power supply from the battery to the control circuit via the switching element is started, and The control circuit starts up. Then, the switching element is held in a conductive state by the power supply holding unit of the control circuit, the power supply from the battery to the control circuit is continued, and the combustion operation of the burner is started by the combustion operation unit. The

  And even if the combustion operation section ends the combustion operation of the burner, power supply from the battery to the control circuit is continued, and a predetermined time has elapsed from the end of the combustion operation of the burner, and the thermocouple When the temperature of the thermocouple decreases, the thermocouple abnormality detection unit detects whether the thermocouple is abnormal. As described above, in the combustion apparatus that operates using the battery as a power source by continuously supplying power from the battery to the control circuit even after the burner burn operation is completed, and detecting whether or not the thermocouple is abnormal. In addition, the presence or absence of abnormality of the thermocouple can be detected more reliably.

  Further, when the presence or absence of the abnormality of the thermocouple by the thermocouple abnormality detection unit is completed, the switching element is cut off by the power supply interruption unit, and the power supply from the battery to the control circuit is stopped. . Therefore, consumption of the battery can be suppressed.

In addition, the control circuit has an abnormality notifying unit that notifies when the thermocouple abnormality is detected by the thermocouple abnormality detecting unit, and the power supply cutoff unit is provided by the thermocouple abnormality detecting unit. When no abnormality of the thermocouple is detected, when the detection of the presence or absence of abnormality of the thermocouple by the thermocouple abnormality detection unit is completed, the switching element is turned off, and the thermocouple abnormality detection unit detects the thermocouple abnormality. When the abnormality of the pair is detected, the switching element is put into a cut-off state when the notification by the abnormality notification unit is completed.

According to the present invention, when the abnormality of the thermocouple is detected by the thermocouple abnormality detection unit, the abnormality notification unit notifies the switching element by the power supply interruption unit after the abnormality notification unit performs the notification. As a result, consumption of the battery can be suppressed after prompting the user to perform repair or the like.

  The thermocouple abnormality detector includes a nonvolatile memory, and when the abnormality of the thermocouple is detected, the abnormality of the thermocouple is written to the nonvolatile memory indicating that the thermocouple is in an abnormal state. It is characterized by that.

  According to the present invention, when the abnormality of the thermocouple is detected by the thermocouple abnormality detection unit, the nonvolatile circuit can be used even after the power supply from the battery to the control circuit is interrupted by the drive circuit. The abnormality occurrence data is held in the memory. Therefore, when the ignition operation by the operation switch is performed while suppressing the consumption of the battery, measures such as determining whether or not the abnormality occurrence data is written to the nonvolatile memory and notifying the abnormality are taken. Can do.

The block diagram of the gas stove which is a combustion apparatus of this invention. The flowchart of the process by a power supply holding | maintenance part, a combustion operation part, and a thermocouple abnormality detection part. The flowchart of the process by a thermocouple abnormality detection part, an abnormality alerting | reporting part, and a power supply interruption | blocking part.

  Embodiments of the present invention will be described with reference to FIGS.

  Referring to FIG. 1, the combustion apparatus of the present embodiment is a gas stove that operates using a battery 1 as a power source. This gas stove has an operation switch 10 for a user to instruct ignition and extinguishing of a burner (not shown). A gas solenoid valve 30 provided in a gas supply path (not shown) connected to the burner, a thermocouple 20 provided in the vicinity of the burner for detecting the burned state of the burner, a pilot lamp 33, and a gas stove A microcomputer 50 (corresponding to a control circuit of the present invention; hereinafter referred to as a microcomputer 50) for controlling the overall operation is provided.

The microcomputer 50 is operated by power supplied from the battery 1 via the transistor 2 (corresponding to the switching element of the present invention), and the base terminal of the transistor 2 is connected to the driving element 12 and the driving element 16 via the resistor 14. It is connected. Further, the microcomputer 50 includes an E ² PROM 56 (corresponding to the nonvolatile memory of the present invention).

  The input terminal of the drive element 12 is connected to the positive electrode of the battery 1 via the operation switch 10 and grounded (connected to the 0 V potential portion) via the resistor 11. With this configuration, when the operation switch 10 is turned on (conductive state) by the user's ignition operation, a base current flows from the base terminal of the transistor 2 to the buffer 12 and the transistor 2 is conductive (emitter terminal and collector terminal). The space is in a conductive state).

  A drive circuit connected between the positive electrode of the battery 1 and the base terminal of the transistor 2 to bring the switching element into a conductive state when the operation switch of the present invention is turned on by the operation switch 10, the drive element 12, and the resistor 14. Is configured.

  The input terminal of the drive element 16 is connected to the output port Po1 of the microcomputer 50. When the output level of the output port Po1 is High (Vcc level), the base current flows from the base terminal of the transistor 2 to the buffer 16. The transistor 2 becomes conductive (the conductive state is between the emitter terminal and the collector terminal).

  When the operation switch 10 is off (open state) and the output level of the output port Po1 of the microcomputer 50 is low (0 V level), the base current of the transistor 2 does not flow, so that the transistor 2 is in the cut-off state ( Emitter terminal and collector terminal are cut off).

  One end of the thermocouple 20 is connected to an AD (Analog / Digital) input port of the microcomputer 50 via a TC (Thermo Couple) amplifier 21 and the other end is grounded. The detection signal of the thermocouple 20 is amplified by the amplifier circuit 21 and input to the AD input port of the microcomputer 50, converted into a digital value, and read into the microcomputer 50.

  One end of the gas solenoid valve 30 is connected to the output port Po2 of the microcomputer 50 via the resistor 31 and the drive element 32, and the other end is grounded (connected to the 0V potential portion). When the output level of the output port Po2 of the microcomputer 50 is High (Vcc level), the solenoid valve 30 is closed, and when the output level of Po2 is Low (0 V level), the solenoid valve 30 is opened. It becomes a valve state.

  One end of the pilot lamp 33 is connected to the output port Po2 of the microcomputer 50 via the resistor 34 and the driving element 35, and the other end is connected to the Vcc potential portion. When the output level of the output port Po3 of the microcomputer 50 is High (Vcc level), the pilot lamp 33 is turned on. When the output level of Po3 is Low (0 V level), the pilot lamp 33 is turned off. It becomes.

  The microcomputer 50 executes a gas stove control program held in a memory (not shown) to thereby provide a power supply holding unit 51, a combustion operation unit 52, a thermocouple abnormality detection unit 53, an abnormality notification unit 54, and a power supply. It functions as the blocking unit 55 and executes processing according to the flowcharts shown in FIGS.

  Hereinafter, processing by the power supply holding unit 51, the combustion operation unit 52, the thermocouple abnormality detection unit 53, the abnormality notification unit 54, and the power supply cutoff unit 55 will be described according to the flowcharts shown in FIGS.

  When the operation switch 10 is turned on and the transistor 2 is turned on by the driving element 12, and the power supply from the battery 1 to the control circuit 50 via the transistor 2 is started, the microcomputer 50 operates as shown in FIGS. The flowchart is executed.

  Steps 1 to 2 in FIG. 2 are processes performed by the power supply holding unit 51. When the operation switch 10 is turned on in STEP1 and the power supply holding unit 51 detects that the input to the input port Pi1 is High (Vcc level), the power supply holding unit 51 proceeds to STEP2. In STEP2, the power supply holding unit 51 maintains the output level of the output port Po1 at High. Thereby, the transistor 2 is held in a conductive state, and the state where power is supplied from the battery 1 to the microcomputer 50 is maintained.

  Subsequent STEP 3 to STEP 6 and STEP 20 to STEP 21 are processes performed by the combustion operation unit 52. The combustion operation section 52 performs burner ignition processing in STEP3, repeatedly executes the loop of STEP4 to STEP6, performs the combustion operation of the burner in STEP4, and detects the detection signal of the thermocouple 20 read from the AD port in STEP5. Whether or not the burner is misfired is detected from the digital value, and whether or not the operation switch 10 is turned off (whether the burner is extinguished or not) is detected from the input level of the input port Pi1 in STEP6.

  When the operation switch 10 is OFF in STEP 6, the process proceeds to STEP 7. The combustion operation unit 52 closes the gas electromagnetic valve 30, extinguishes the burner, ends the combustion operation, and proceeds to STEP 8.

  Further, when the misfire of the burner is detected in STEP 5, the process branches to STEP 20, and the combustion operation unit 52 closes the gas electromagnetic valve 30 and proceeds to STEP 21. Then, the combustion operation unit 52 performs a misfire error notification due to the blinking of the pilot lamp 33 at STEP 21, and proceeds to STEP 8 when it is detected that the operation switch 10 is turned off at STEP 22.

  3 from STEP 8 to STEP 10 in FIG. 3 is processing by the thermocouple abnormality detection unit 53. The thermocouple abnormality detection unit 53 starts a failure detection timer (for example, the time-up time is set to 60 seconds) in STEP8. Then, after waiting for the failure detection timer to expire in the next STEP 9, the process proceeds to STEP 10 in FIG. 3, and the thermocouple abnormality detection unit 53 determines that the digital value of the detection signal of the thermocouple 20 read from the AD port is a predetermined value. When it is above the abnormality detection level, it is determined that the thermocouple 20 is in an abnormal state.

  STEP 30 to STEP 33 branched from the subsequent STEP 11 and STEP 11 are processes by the abnormality notification unit 54. In STEP 11, the abnormality detection unit 54 determines whether or not an abnormality of the thermocouple 20 is detected. If no abnormality of the thermocouple 20 is detected, the process proceeds to STEP 12, and if an abnormality of the thermocouple 20 is detected, STEP 30 is detected. Branch to

  STEP 30 to STEP 33 are abnormality notification processes. The abnormality detection unit 54 starts an error notification timer (for example, the time-up time is set to 30 seconds) in STEP 30, and turns on the pilot lamp 33 in STEP 31. The user is informed that the thermocouple 20 is in an abnormal state and the gas stove cannot be used (error notification ON).

  When the error notification timer expires, the process proceeds to STEP 33, where the abnormality notification unit 54 turns off the pilot lamp 33 and proceeds to STEP 12. The abnormality notification of the thermocouple 20 may be performed by using other methods such as displaying an error code on a 7-segment LED / LCD (not shown) or sounding a buzzer.

  STEP 12 is processing performed by the power supply cutoff unit 55. The power supply cut-off unit 55 releases the holding of the output port Po1 to High (Vcc level) by the power supply holding unit 51 and sets the output port Po1 to Low (0 V). As a result, the transistor 2 is turned off. As a result, the power supply from the battery 1 to the microcomputer 50 is stopped, the operation of the microcomputer 50 is stopped, and the subsequent consumption of the battery 1 is suppressed.

  In the abnormality determination process of the thermocouple 20 in STEP 10, the digital value of the detection signal of the thermocouple 20 is continuously higher than the abnormality detection level until the time-up time (60 seconds) of the failure detection timer elapses. When it is determined that the thermocouple 20 is in an abnormal state and the digital value of the detection signal of the thermocouple 20 becomes lower than the abnormality detection level within the time-up time, the thermocouple 20 is not in an abnormal state at that time. May be determined. In this case, when the thermocouple 20 is not in an abnormal state, the abnormality determination process can be terminated quickly, so that the battery 1 can be prevented from being consumed.

  Further, in the abnormality determination process of the thermocouple 20 in STEP 10 of FIG. 3, when it is determined that the thermocouple 20 is abnormal, the use of the gas stove is prohibited by not accepting subsequent input of the operation switch 10. (Switch input lock state).

Further, in the abnormality determination process of the thermocouple 20 in STEP 10 of FIG. 3, when it is determined that the thermocouple 20 is abnormal, thermocouple abnormality data indicating the occurrence of the abnormality of the thermocouple 20 is written in the E ² PROM 56. May be included.

In this case, when the operation switch 10 is ignited in STEP 1 of FIG. 2, it is confirmed whether or not the thermocouple abnormality data is written in the E ² PROM 56, and the thermocouple abnormality data is written. In this case, the abnormality notification can be performed while the exhaustion of the battery 1 is suppressed, and the effective abnormality notification limited to the timing when the user is located near the gas stove can be performed.

  In the present embodiment, the gas stove is shown as the combustion apparatus of the present invention. However, the present invention can be applied to any combustion apparatus that operates with a battery as a power source and detects the combustion state of the burner with a thermocouple. is there.

  In this embodiment, the transistor 2 is used as the switching element of the present invention. However, an FET or a relay may be used.

In the present embodiment, as shown in FIG. 1, the microcomputer 50 includes the E ² PROM 56 built-in, but an E ² PROM in a package different from the microcomputer 50 may be provided.

  DESCRIPTION OF SYMBOLS 1 ... Battery, 2 ... Transistor (switching element), 10 ... Operation switch, 12 ... Drive element, 20 ... Thermocouple, 30 ... Gas solenoid valve, 33 ... Pilot lamp, 50 ... Microcomputer, 51 ... Power supply holding | maintenance part, 52 ... Combustion operation part, 53 ... Thermocouple abnormality detection part, 54 ... Abnormality notification part, 55 ... Power supply interruption | blocking part.

Claims (3)

With a burner,
A thermocouple for detecting the combustion state of the burner;
An operation switch for instructing ignition and extinguishing of the burner;
Battery,
A switching element;
A drive circuit for bringing the switching element into a conductive state when the operation switch is turned on;
A combustion apparatus including a control circuit that is connected to the battery via the switching element and that is operated by electric power supplied from the battery via the switching element to control the operation of the burner;
The control circuit includes:
A power supply holding unit that holds the switching element in a conductive state regardless of whether the operation switch is on or off when the switching element is turned on by the drive circuit and power supply from the battery is started. When,
The combustion operation of the burner is started in response to the ignition operation by the operation switch, and when a fire extinguishing operation is performed by the operation switch during the combustion operation of the burner, and when the misfire of the burner is detected by the thermocouple And a combustion operation section for terminating the combustion operation of the burner,
A thermocouple abnormality detection unit that detects the presence or absence of abnormality of the thermocouple when a predetermined time has passed without ignition operation by the operation switch from the end of the combustion operation of the burner by the combustion operation unit;
After the detection of the presence / absence of abnormality of the thermocouple by the thermocouple abnormality detection unit is finished, the power supply that releases the holding state of the switching element by the power supply holding unit and shuts off the switching element A combustion apparatus comprising a blocking portion. The combustion apparatus according to claim 1, wherein
The control circuit has an abnormality notifying unit that notifies when an abnormality of the thermocouple is detected by the thermocouple abnormality detecting unit,
The power supply cutoff unit, when the abnormality of the thermocouple by the thermocouple abnormality detection portion is not detected, the switching element when the detection of the presence of the thermocouple by the thermocouple abnormality detection unit anomaly has ended The combustion apparatus is characterized in that when the abnormality of the thermocouple is detected by the thermocouple abnormality detection unit, the switching element is turned off when the notification by the abnormality notification unit is completed. The combustion apparatus according to claim 2, wherein
With non-volatile memory,
The said thermocouple abnormality detection part writes the thermocouple abnormality data which shows that the said thermocouple is in an abnormal state in the said non-volatile memory, when the abnormality of the said thermocouple is detected.

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