JP5160182B2 - Gas cooker - Google Patents

Description

  The present invention relates to a gas cooker, and more particularly to a gas cooker that detects misfire of a burner with an output voltage of a thermocouple provided in the burner.

Conventionally, during combustion of the burner, the solenoid valve provided in the gas supply pipe to the burner is kept open by the thermoelectromotive force of the thermocouple, and when the flame disappears and the thermoelectromotive force decreases, the solenoid valve is closed to A gas cooking device that can prevent outflow is known (see, for example, Patent Document 1). In this type of gas cooking device, the thermoelectromotive force generated by the thermocouple is amplified by the amplifier circuit on the electrical board and input to the input terminal of the control circuit as a voltage signal. In the control circuit, if the value input to the input terminal exceeds a predetermined threshold value, the burner combustion is continued. If it is less than or equal to the threshold value, there is a high possibility that the flame disappears in the burner. In this case, in order to prevent gas outflow due to extinction, the solenoid valve is closed and combustion of the burner is stopped.
Japanese Patent Laid-Open No. 9-60881

  However, such a gas cooker has numerical limitations on the input terminal of the control circuit. In addition to a thermocouple, a plurality of input terminals provided in the control circuit are connected to a power supply voltage monitoring circuit, an input circuit of a thermistor for detecting a heating temperature by a burner, and the like. In particular, in a gas stove, a thermocouple is provided in each of the stove and the grill, but since a plurality of grill burners are provided in the grill, it is necessary to install thermocouples corresponding to the number. Therefore, the number of input terminals necessary for the control circuit inevitably increases. Therefore, it is necessary to take measures by selecting a control circuit with higher specifications and having more input terminals than before, or by providing a comparison element such as a comparator outside, which has been a cause of cost increase. Further, an input circuit for amplifying and inputting a voltage signal from the thermocouple must be provided corresponding to a plurality of thermocouples, which causes a problem that the circuit configuration on the electrical board is complicated.

  The present invention has been made to solve the above problems, and provides a gas cooking device that can save the number of input terminals used when inputting analog signals from a plurality of thermocouples to a control circuit. For the purpose.

In order to achieve the above object, a gas cooker according to a first aspect of the present invention includes a plurality of burners, an electromagnetic valve that controls fuel supply to the plurality of burners, and each of the plurality of burners. A gas heating cooker provided with a plurality of thermocouples for detecting the flame of the burner, and a control circuit for controlling the driving of the solenoid valve based on voltage signals output from the plurality of thermocouples, respectively. A plurality of switching circuits that are respectively connected to the plurality of thermocouples and that turn on / off voltage signals output from the thermocouples, and a plurality of switching pulses that switch switch timings of the plurality of switching circuits. Output to each of the switching circuits, and by changing the output of the switching pulse, the plurality of thermocouples in the plurality of switching circuits respectively output. A switch control means for switching on and off the order of the voltage signal that, connected to said plurality of switching circuits, in response to the output of the switching pulse the switch control means outputs are sequentially output from said plurality of switching circuits An input circuit that amplifies each voltage signal of the plurality of thermocouples and sequentially inputs the voltage signal to an input terminal of the control circuit, and the switch control means has a predetermined pause period immediately before switching the switch timing. In the pause period, the output of the switching pulse is changed prior to the switching timing.

  In addition to the configuration of the invention according to claim 1, the gas cooking device of the invention according to claim 2 includes all the voltages input from the input circuit in a state where the plurality of switching circuits are turned off. Confirming means for confirming whether or not the signal is less than or equal to a predetermined value; and when the confirming means determines that any of the voltage signals input from the input circuit is not less than or equal to the predetermined value, the solenoid valve is forced Valve closing instruction means for instructing to close the valve automatically.

  In the gas cooking device of the invention according to claim 1, the switch control means controls the switch timings of the plurality of switching circuits respectively connected to the plurality of thermocouples. That is, by controlling on / off of each switching circuit connected to each of the plurality of thermocouples, a plurality of voltage signals respectively output from the plurality of thermocouples can be taken out one by one. The voltage signals taken out one by one are amplified by the input circuit and sequentially input to the input terminals of the control circuit. Therefore, a plurality of voltage signals output from the plurality of thermocouples can be input to one input terminal of the control circuit, so that the number of input terminals used for the thermocouple can be saved. Since the number of input terminals can be saved, the number of thermocouples can be increased corresponding to the number of burners.

  Further, in the gas cooking device of the invention according to claim 2, in addition to the effect of the invention of claim 1, in order to quickly grasp the failure of the switching circuit, a plurality of switching circuits are turned off, The confirmation means confirms whether all voltage signals input from the input circuit are equal to or less than a predetermined value. When all the switching circuits are turned off, all voltage signals input from the input circuit are equal to or less than a predetermined value if normal. If any of the voltage signals is not less than the predetermined value, it is considered that the switching circuit has failed. In this case, the valve closing instruction means forcibly closes the electromagnetic valve. Therefore, a safer gas cooking device can be provided.

  Hereinafter, a built-in stove 1 according to an embodiment of the present invention will be described with reference to the drawings. The built-in stove 1 (see FIG. 1) of the present embodiment is incorporated into a kitchen unit by dropping and locking the appliance 2 into an opening formed in a counter top of the kitchen unit (not shown). is there. And by reading the thermoelectromotive force of the thermocouple installed in various burners, the misfire etc. of various burners are detected rapidly, and the safety function which interrupts | blocks gas supply forcibly is provided.

  First, the structure of the built-in stove 1 will be schematically described with reference to FIGS. FIG. 1 is a perspective view of the built-in stove 1, and FIG. 2 is a plan view of the built-in stove 1. The built-in stove 1 includes a substantially rectangular parallelepiped tool 2. A standard burner 5 is provided on the left side of the top surface of the instrument 2, and a high-power burner 6 is provided on the right side. A firewood burner 7 for melting fire is provided behind the standard burner 5 and the high thermal power burner 6. A grill exhaust port (not shown) is provided behind the firewood burner 7. The grill exhaust port is covered with exhaust covers 10, 11 having a plurality of exhaust holes and having a horizontally long rectangular shape in plan view. On the top surface of the appliance 2 having such a structure, a top plate 3 that is open so as to expose the standard burner 5, the high thermal power burner 6, the firewood burner 7, and the grill exhaust port is provided. On the top surface of the top plate 3, five virtues 5a, 6a, 7a for placing cooking pots (not shown) are respectively installed so as to surround the standard burner 5, the high thermal power burner 6 and the firewood burner 7. ing.

  A grill box (not shown), which is the main body of the grill, is incorporated in the center of the appliance 2. A pair of left and right grill burners A and B (not shown) are provided on the upper side of the grill cabinet, and a pair of left and right grill burners C and D (not shown) are also provided on the lower side. In the center of the front of the appliance 2, a grill window 13 is provided for checking the inside of the grill cabinet. Below the grill window 13, a grill handle 14 is provided so as to project forward from the inside of the grill cabinet to draw a tray (not shown) and a grill (not shown) forward.

  An ignition button 15 for igniting the standard burner 5 is provided on the left side of the front of the instrument 2, and an ignition button 17 for igniting the soot burner 7 is provided on the right side thereof. An ignition button 16 for igniting the high-power burner 6 is provided on the front right side of the appliance 2, and an ignition button for igniting the grill burners A, B, C, and D in the grill cabinet at the left is provided on the left side of the ignition button 16. 18 is provided. The ignition buttons 15, 16, 17, and 18 have built-in cock switches 15a, 16a, 17a, and 18a (see FIG. 3) that are turned on and off by the operation of these buttons.

  Further, immediately above the ignition button 15, a thermal power adjustment lever 15b for manually adjusting the thermal power of the standard burner 5 is provided so as to be rotatable in the left-right direction. Immediately above the ignition button 17, a thermal power adjusting lever 17 b for manually adjusting the thermal power of the burner 7 is provided so as to be rotatable in the left-right direction. Immediately above the ignition button 16, a thermal power adjustment lever 16b for manually adjusting the thermal power of the high thermal power burner 6 is provided so as to be rotatable in the left-right direction. Immediately above the ignition button 18, a thermal power adjustment lever 18b for manually adjusting the thermal power of the grill burners A, B, C, D is provided so as to be rotatable in the left-right direction. An operation panel 20 for operating the built-in stove 1 is provided below the ignition buttons 15 and 17 so as to be openable and closable in the forward direction. A battery box 21 for storing two dry batteries is provided below the ignition buttons 16 and 18.

  An igniter 27 (see FIG. 3) for sparking and igniting the ignition electrode is connected to each of the standard burner 5, high thermal power burner 6, firewood burner 7, and grill burners A, B, C, and D. These various burners are each provided with a thermocouple for detecting ignition and misfire. Specifically, the standard burner 5 is provided with a first thermocouple 31 (see FIG. 3), the high-temperature burner 6 is provided with a second thermocouple 32, and the soot burner 7 is provided with a third thermocouple 31. A thermocouple 33 (see FIG. 3) is provided. The grill burner A is provided with a fourth thermocouple 34 (see FIG. 3), the grill burner B is provided with a fifth thermocouple 35 (see FIG. 3), and the grill burner C is provided with a sixth thermocouple 36 (see FIG. 3). 3), and the grill burner D is provided with a seventh thermocouple 37 (see FIG. 3). That is, the first thermocouple 31, the second thermocouple 32, and the third thermocouple 33 are installed on the stove side, and the fourth thermocouple 34, the fifth thermocouple 35, the sixth thermocouple 36, and the seventh thermocouple 37. Is installed on the grill side.

  Further, the standard burner 5 is provided with a thermistor 23 (see FIG. 3) for detecting the bottom temperature of the cooking pot placed on the five virtues 5a. In addition, a grill thermistor 24 is provided in the vicinity of the communication opening between the grill cabinet and the exhaust passage so as to detect the temperature in the grill cabinet.

  Further, on the inside of the instrument 2, a first gas supply pipe (not shown) for supplying gas to the standard burner 5 and a second gas supply pipe (not shown) for supplying gas to the high thermal power burner 6 are provided. And a third gas supply pipe (not shown) for supplying gas to the burner burner 7 and a fourth gas supply pipe (not shown) for supplying gas to the grill burners A, B, C and D, respectively. Is provided. The first gas supply pipe is provided with a safety valve 38 (see FIG. 3) for shutting off the gas supply, and the second gas supply pipe is provided with a safety valve 39 (see FIG. 3) for shutting off the gas supply. The gas supply pipe is provided with a safety valve 40 (see FIG. 3) for shutting off the gas supply, and the fourth gas supply pipe is provided with a safety valve 41 (see FIG. 3) for shutting off the gas supply. These safety valves 38 to 41 are magnet type electromagnetic valves for forcibly extinguishing various burners by shutting off the gas supply.

  Further, the first gas supply pipe is provided with a heating power adjustment switching valve 28 for controlling the gas supply amount. The thermal power adjustment switching valve 28 is a switching valve for switching the magnitude of the thermal power of the standard burner 5 in order to maintain the heating temperature by the standard burner 5 detected by the thermistor 23 within a predetermined temperature range. The thermal power adjustment switching valve 28 is controlled by a CPU of a microcomputer control circuit 50 described later.

  Next, the electrical configuration of the built-in stove 1 will be described with reference to FIG. FIG. 3 is a block diagram showing an electrical configuration of the built-in stove 1. The built-in stove 1 includes an electrical board 70. The electrical board 70 is provided with a microcomputer control circuit 50 that controls the combustion operation of the built-in stove 1. The microcomputer control circuit 50 includes a CPU (not shown), various control programs, a ROM that stores initial values of various data, a RAM that temporarily stores data generated during arithmetic processing of the CPU, a timer, and a non-volatile flash memory. Etc.

  The microcomputer control circuit 50 includes a power supply circuit 43 that supplies the voltage of the dry battery stored in the battery box 21 (see FIG. 1) to various circuits on the electrical board 70, and an on / off output from each of the cock switches 15a to 18a. The switch input circuit 44 for inputting signals, the thermistor input circuit 45 for inputting analog signals output from the thermistors 23 and 24, the operation panel communication circuit 46 for communicating with the operation panel 20, and the igniter 27 are driven. An igniter circuit 47, a switching valve circuit 48 for driving the thermal power adjustment switching valve 28, and a safety valve circuit 49 for driving the four safety valves 38 to 41 are connected to each other.

  Further, the microcomputer control circuit 50 is provided with eight analog channels for analog input (hereinafter referred to as analog CH). Four of them, CH1 to CH4 (see FIG. 4), are used for analog input of the thermocouple. A first thermocouple input circuit 51 that amplifies and inputs the thermoelectromotive force output from the first thermocouple 31 of the standard burner 5 is connected to the analog CH1 (see FIG. 4). A second thermocouple input circuit 52 that amplifies and inputs the thermoelectromotive force output from the second thermocouple 32 of the high thermal power burner 6 is connected to the analog CH2 (see FIG. 4). A third thermocouple input circuit 53 that amplifies and inputs the thermoelectromotive force output from the third thermocouple 33 of the soot burner 7 is connected to the analog CH3 (see FIG. 4). A fourth thermocouple input circuit 54 that amplifies and inputs the thermoelectromotive force output from the fourth to seventh thermocouples 34 to 37 of the grill burners A to D one by one is connected to the analog CH4 (see FIG. 4). ing. The other analog CH is connected to the dry battery voltage from the power supply circuit 43, the thermistors 23, 24, and the like.

  By the way, in the electrical substrate 70, the 4th thermocouple 34-the 7th thermocouple 37 provided in the grill warehouse are each connected to FET circuit 64-67 which is a switching element. Specifically, the fourth thermocouple 34 is connected to the source side of the FET circuit 64. The fifth thermocouple 35 is connected to the source side of the FET circuit 65. The sixth thermocouple 36 is connected to the source side of the FET circuit 66. The seventh thermocouple 37 is connected to the source side of the FET circuit 67. Further, the drain side of the FET circuits 64 to 67 is connected to the fourth thermocouple input circuit 54, and the gate side is connected to the microcomputer control circuit 50. The switch timings of the FET circuits 64 to 67 are controlled by the CPU of the microcomputer control circuit 50. As a result, the four thermoelectromotive forces output from the fourth thermocouple 34 to the seventh thermocouple 37 are sequentially read one by one, amplified by the fourth thermocouple input circuit 54, and analog CH4 of the microcomputer control circuit 50. (See FIG. 3).

  Next, the disappearing safety function of various burners by the thermocouple will be described with reference to FIG. For example, when the ignition button 15 (see FIG. 1) of the standard burner 5 (see FIG. 2) is pressed, the main valve (not shown) is opened in conjunction with the pressing operation of the ignition button 15. At this time, a magnet holding current flows through the coil of the safety valve 38 corresponding to the standard burner 5 and is excited. As a result, the safety valve 38 is held in the suction open state. Next, gas is supplied to the standard burner 5 via the first gas supply pipe (not shown), the igniter 27 is driven, and the standard burner 5 is ignited. When the standard burner 5 is ignited, the first thermocouple 31 is heated by the combustion flame formed at the flame outlet. At this time, a thermoelectromotive force is generated in the first thermocouple 31. The generated thermoelectromotive force is amplified by the first thermocouple input circuit 51 and input to the analog CH1 of the microcomputer control circuit 50.

  The microcomputer control circuit 50 controls the safety valve circuit 49 to supply the suction holding current to the safety valve 38 while the input thermoelectromotive force is equal to or higher than a predetermined level. On the other hand, when the thermoelectromotive force falls below a predetermined level due to the extinction of the flame, the supply of the adsorption holding current is stopped and the safety valve 38 is closed. As a result, the gas supply to the standard burner 5 is shut off, and the first thermocouple 31 disappears and the safety function is activated. The same applies to the second thermocouple 32 to the seventh thermocouple 37.

  Next, the check timing of the thermocouple check process will be described with reference to the timing chart of FIG. FIG. 4 is a timing chart of thermocouple check processing by the CPU. In the thermocouple check process, the thermoelectromotive force output from each of the first thermocouple 31 to the seventh thermocouple 37 (see FIG. 3) is read and an abnormality check such as misfire or failure is performed. This thermocouple check process is performed at 13 timings divided at t0 to t12. One timing unit is 2 (msec). Therefore, one reading cycle is 13 (timing) × 2 (msec) = 26 (msec).

  In one reading cycle, at the timings t0 to t3, the thermoelectromotive forces output from the first thermocouple 31 to the third thermocouple 33 are checked. At the timing t4, zero check processing for detecting an abnormality in the FET circuits 64 to 67 is performed. At the timings t5 to t12, the thermoelectromotive forces output from the fourth thermocouple 34 to the seventh thermocouple 37 are checked. In the check of the fourth thermocouple 34 to the seventh thermocouple 37, the on / off of the FET circuits 64 to 67 is switched by time division control. Thereby, the four thermoelectromotive forces output from the fourth thermocouple 34 to the seventh thermocouple 37 can be read one by one.

  Next, a switch timing switching control method for the FET circuits 64 to 67 will be described with reference to FIGS. The microcomputer control circuit 50 includes four switching channels (see FIG. 4; hereinafter referred to as switching CH) corresponding to the FET circuits 64 to 67, respectively. The switching CH1 corresponds to the FET circuit 64, the switching CH2 corresponds to the FET circuit 65, the switching CH3 corresponds to the FET circuit 66, and the switching CH4 corresponds to the FET circuit 67. From these four switching CHs, switching pulses instructing on / off of the FET circuits 64 to 67 are respectively output. As shown in FIG. 4, when instructing on, a high level signal (hereinafter referred to as H signal) is output, and when instructing off, a low level signal (hereinafter referred to as L signal) is output. The

  For example, when an H signal is output from the switching CH1 and an L signal is output from the switching CH2 to 4, only the FET circuit 64 corresponding to the switching CH1 is turned on, and the other FET circuits 65 to 67 are turned off. In this case, only the thermoelectromotive force output from the fourth thermocouple 34 is read into the analog CH 4 of the microcomputer control circuit 50. Therefore, the four thermoelectromotive forces output from the fourth thermocouple 34 to the seventh thermocouple 37 can be read one by one by changing the switching pulse and sequentially switching the FET circuits 64 to 67 on and off.

  Further, in checking the fourth thermocouple 34 to the seventh thermocouple 37, in order to stabilize the waveform after changing the output of the switching pulse, a rest period of 2 (msec) is provided at a predetermined timing. For example, among the timings t5 to t12, the thermoelectromotive forces of the fourth thermocouple 34 to the seventh thermocouple 37 are read at the timing t6, t8, t10, and t12, and 2 timings at the timing t5, t7, t9, and t11. (Msec) idle period is provided. In this idle period, the switching pulse output is changed prior to the next timing. Thereby, since the waveform of the switching pulse is stabilized and then the next timing is reached, the FET circuits 64 to 67 can be reliably turned on and off at the timings t6, t8, t10, and t12.

  Next, the thermocouple check process by the CPU will be described with reference to the timing chart of FIG. 4 and the flowcharts of FIGS. 5 is a main flowchart of the thermocouple check process by the CPU, FIG. 6 is a flowchart of the stove side TC check process shown in FIG. 5, and FIG. 7 is a flowchart of the zero check process shown in FIG. 8 is a flowchart of the grill side TC check process shown in FIG. 5, FIG. 9 is a flowchart showing the continuation of FIG. 8, FIG. 10 is a flowchart showing the continuation of FIG. 9, and FIG. FIG. 11 is a flowchart showing a continuation of FIG. 10.

  As shown in FIG. 5, it is first determined whether any of the cock switches 15a to 18a built in the ignition buttons 15 to 18 is turned on (S1). When none of the cock switches 15a to 18a is pressed (S1: NO), the process returns to S1 and the on / off of the cock switches 15a to 18a is continuously monitored. If it is determined that any one of the cock switches 15a to 18a is turned on (S1: YES), the stove side TC check process is executed after a suspension period of 2 (msec) at timing t0 (S2). .

  The stove side TC check process will be described with reference to FIG. In the stove side TC check process, the thermoelectromotive forces output from the first thermocouple 31, the second thermocouple 32, and the third thermocouple 33 are read in order. Therefore, during the timing t0 to t3, all switching pulses output from the switching CH1 to CH4 are L signals, and all the FET circuits 64 to 67 are turned off.

  First, at the timing t1, it is determined whether the thermoelectromotive force output from the first thermocouple 31 is a misfire voltage (S6). That is, it is determined whether or not the input voltage amplified by the first thermocouple input circuit 51 and input to the analog CH1 is lower than a predetermined level stored in the flash memory (not shown) of the microcomputer control circuit 50. . If the cock switch 15a corresponding to the standard burner 5 is not turned on, it is not determined as a misfire voltage even if the input voltage is below a predetermined level.

  When it is determined that the input voltage is a misfire voltage (S6: YES), the safety valve 38 corresponding to the standard burner 5 is closed for safety (S12). As a result, the first gas supply pipe that supplies gas to the standard burner 5 is shut off, so that gas leakage due to extinction can be prevented.

  Next, it is determined whether or not the ignition button 15 is pressed again and the cock switch 15a is turned on again (S13). While it is not turned on again (S13: NO), the process returns to S13 and the depression of the ignition button 15 is monitored. If it is determined that the ignition button 15 has been pressed again (S13: YES), the safety valve 38 is opened (S14), the process returns to S6, and the stove side TC check process is executed from the beginning.

  By the way, when the input voltage is not determined to be a misfire voltage (S6: NO), it is determined whether the thermoelectromotive force is an abnormal voltage (S7). Here, it is determined whether or not the input voltage exceeds the upper limit value of the allowable range stored in the flash memory. When the upper limit value of the allowable range is exceeded (S7: YES), an abnormality of the standard burner 5, an abnormality of the first thermocouple 31, an abnormality of the first thermocouple input circuit 51, etc. are conceivable. In this state, the combustion state of the standard burner 5 cannot be detected accurately. In this case, the safety valve 38 corresponding to the standard burner 5 is closed (S15), and the standard burner 5 is extinguished. Then, without interlocking with the operation of the ignition button 15, the processing ends with the safety valve 38 being closed. That is, by preventing reignition, it is possible to prevent a new combustion trouble or the like from being induced. On the other hand, when the input voltage is not determined to be an abnormal voltage (S7: NO), the thermoelectromotive force from the first thermocouple 31 is normal, so the second thermocouple 32 provided in the high thermal power burner 6 is checked. It is transferred to.

  Next, at the timing t2, it is determined whether or not the thermoelectromotive force output from the second thermocouple 32 is a misfire voltage (S8). That is, it is determined whether or not the input voltage amplified by the second thermocouple input circuit 52 and input to the analog CH2 is lower than a predetermined level stored in the flash memory (not shown) of the microcomputer control circuit 50. . In addition, when the cock switch 16a corresponding to the high thermal power burner 6 is not turned on, it is not determined as a misfire voltage even if the input voltage is below a predetermined level.

  If it is determined that the input voltage is a misfire voltage (S8: YES), the safety valve 39 corresponding to the high thermal power burner 6 is closed for safety (S12). Thereby, since the 2nd gas supply pipe which supplies gas to the strong-fired power burner 6 is interrupted | blocked, the gas leak by extinction can be prevented.

  Next, it is determined whether or not the ignition button 16 is pressed again and the cock switch 16a is turned on again (S13). While it is not turned on again (S13: NO), the process returns to S13 and the depression of the ignition button 16 is monitored. If it is determined that the ignition button 16 has been pressed again (S13: YES), the safety valve 39 is opened (S14), the process returns to S6, and the stove side TC check process is executed from the beginning.

  By the way, when the input voltage is not determined to be a misfire voltage (S8: NO), it is determined whether the electromotive force is an abnormal voltage (S9). Here, it is determined whether or not the input voltage exceeds the upper limit value of the allowable range stored in the flash memory. When the upper limit value of the allowable range is exceeded (S9: YES), abnormalities in the strong thermal burner 6, abnormalities in the second thermocouple 32, abnormalities in the second thermocouple input circuit 52, and the like are conceivable. In this state, the combustion state of the strong thermal power burner 6 cannot be detected accurately. In this case, the safety valve 39 corresponding to the high thermal power burner 6 is closed (S15), and the high thermal power burner 6 is extinguished. Then, without interlocking with the operation of the ignition button 16, the processing ends with the safety valve 39 closed. That is, by preventing reignition, it is possible to prevent a new combustion trouble or the like from being induced. On the other hand, when the input voltage is not determined to be an abnormal voltage (S9: NO), the thermoelectromotive force from the second thermocouple 32 is normal, so the third thermocouple 33 provided in the burner 7 is checked. To be migrated.

  Next, at timing t3, it is determined whether or not the thermoelectromotive force output from the third thermocouple 33 is a misfire voltage (S10). That is, it is determined whether or not the input voltage amplified by the third thermocouple input circuit 53 and input to the analog CH3 is lower than a predetermined level stored in the flash memory (not shown) of the microcomputer control circuit 50. . If the cock switch 17a corresponding to the burner 7 is not turned on, it is not determined as a misfire voltage even if the input voltage is below a predetermined level.

  If it is determined that the input voltage is a misfire voltage (S10: YES), the safety valve 40 corresponding to the soot burner 7 is closed for safety (S12). Thereby, since the 3rd gas supply pipe which supplies gas to the soot burner 7 is interrupted | blocked, the gas leak by extinction can be prevented.

  Next, it is determined whether or not the ignition button 17 is pressed again and the cock switch 17a is turned on again (S13). While it is not turned on again (S13: NO), the process returns to S13 and the depression of the ignition button 17 is monitored. If it is determined that the ignition button 17 has been pressed again (S13: YES), the safety valve 40 is opened (S14), the process returns to S6, and the stove side TC check process is executed from the beginning.

  By the way, when the input voltage is not determined to be a misfire voltage (S10: NO), it is determined whether or not the electromotive force is an abnormal voltage (S11). Here, it is determined whether or not the input voltage exceeds the upper limit value of the allowable range stored in the flash memory. When the upper limit value of the allowable range is exceeded (S11: YES), the burner 7 abnormality, the third thermocouple 33 abnormality, the third thermocouple input circuit 53 abnormality, etc. are conceivable. In this state, the combustion state of the soot burner 7 cannot be detected accurately. In this case, the safety valve 40 corresponding to the soot burner 7 is closed (S15), and the soot burner 7 is extinguished. Then, without interlocking with the operation of the ignition button 17, the processing ends with the safety valve 40 being closed. That is, by preventing reignition, it is possible to prevent a new combustion trouble or the like from being induced.

  On the other hand, when the input voltage is not determined to be an abnormal voltage (S11: NO), since the thermoelectromotive force from the third thermocouple 33 is normal, the process of the stove side TC check process ends. Subsequently, returning to the flowchart of FIG. 5, a zero check process for checking the abnormality of the FET circuits 64 to 67 is performed at a timing t4 (S3).

  Next, the zero check process will be described with reference to FIG. The zero check process is a process for confirming that the input voltage to the analog CH of the microcomputer control circuit 50 is substantially zero in a state where the FET circuits 64 to 67 are turned off. Therefore, at the timing t4, all the switching pulses output from the switching CH1 to CH4 are L signals, and all the FET circuits 64 to 67 are turned off. It is determined whether or not an abnormal voltage is input to the analog CH4 in a state where the FET circuits 64 to 67 are turned off (S16). That is, it is determined whether or not an abnormal voltage is output from any of the FET circuits 64 to 67 and is input to the analog CH 4 of the microcomputer control circuit 50 via the fourth thermocouple input circuit 54.

  Here, an operational amplifier (amplifying element) is used for the fourth thermocouple input circuit 54. Therefore, the fourth thermocouple input circuit 54 has a characteristic of outputting a slight voltage (offset voltage) even when there is no input from the FET circuits 64 to 67. Therefore, the voltage setting at the time of zero check is set as an offset voltage, and in the process of S16, it is determined whether or not the input voltage to the analog CH4 is equal to or lower than the offset voltage.

  If it is determined that the input voltage to the analog CH4 exceeds the offset voltage (S16: YES), there is a possibility that any of the FET circuits 64 to 67 has failed and is turned on. If the FET circuits 64 to 67 fail, the outputs from the thermocouples 34 to 37 installed in the grill can not be normally detected. Therefore, the safety valve 41 corresponding to the grill burners A to D is closed (S17), and the grill burners A to D are extinguished. Then, without interlocking with the operation of the ignition button 18, the processing ends with the safety valve 41 being closed. That is, by preventing reignition, it is possible to prevent a new combustion trouble or the like from being induced. On the other hand, if the input voltage is not determined to be an abnormal voltage (S16: NO), the FET circuits 64 to 67 are normal, and the zero check process at the timing t4 ends. Subsequently, returning to the flowchart of FIG. 5, the grill side TC check process is executed at timing t5 (S4).

  Next, grill side TC check processing will be described with reference to FIGS. In the grill side TC check process, the fourth thermocouple 34 to the seventh thermocouple 37 are checked while sequentially switching the FET circuits 64 to 67 on and off. First, a rest period of 2 (msec) is set at the timing t5. In this idle period, the switching pulse output is changed prior to the timing t6. That is, the switching pulse of the H signal is output from the switching CH1, and the switching pulse of the L signal is output from the other switching CH2-4. As a result, since the waveform of the switching pulse is stabilized and the timing shifts to the t6 timing, the FET circuits 64 to 67 can be reliably turned on and off.

  Next, the fourth thermocouple 34 is checked at timing t6. As shown in FIG. 8, only the FET circuit 64 corresponding to the switching CH1 is reliably turned on (S18). The thermoelectromotive force output from the fourth thermocouple 34 is amplified by the fourth thermocouple input circuit 54 and input to the analog CH 4 of the microcomputer control circuit 50. Here, it is determined whether or not the thermoelectromotive force output from the fourth thermocouple 34 is a misfire voltage (S19). That is, it is determined whether or not the input voltage of the analog CH4 is below a predetermined level stored in the flash memory. If the cock switch 18a corresponding to the grill burners A, B, C, and D is not turned on, it is not determined as a misfire voltage even if the input voltage is below a predetermined level.

  If the thermoelectromotive force output from the fourth thermocouple 34 is determined to be a misfire voltage (S19: YES), the safety valve 41 corresponding to the grill burners A, B, C, D is closed (S22), 4 Two grill burners are extinguished. Thereby, the disappearance of the grill burner A can be prevented.

  Next, it is determined whether or not the ignition button 18 is pressed again and the cock switch 18a is turned on again (S23). While it is not turned on again (S23: NO), the process returns to S23 and the depression of the ignition button 18 is monitored. When it is determined that the ignition button 18 has been pressed again (S23: YES), the safety valve 41 is opened (S24), the process returns to S18, and the grill side TC check process is executed from the beginning.

  By the way, when the input voltage is not determined to be a misfire voltage (S19: NO), it is determined whether the thermoelectromotive force is an abnormal voltage (S20). Here, it is determined whether or not the input voltage exceeds the upper limit value of the allowable range stored in the flash memory. When the upper limit value of the allowable range is exceeded (S20: YES), an abnormality of the grill burner A, an abnormality of the fourth thermocouple 34, an abnormality of the fourth thermocouple input circuit 54, etc. can be considered. In this state, the combustion state of the grill burner A cannot be accurately detected. In this case, the safety valve 41 corresponding to the grill burners A to D is closed (S25), and the grill burners A to D are extinguished. Then, without interlocking with the operation of the ignition button 18, the processing ends with the safety valve 41 being closed. That is, by preventing reignition, it is possible to prevent a new combustion trouble or the like from being induced.

  On the other hand, when the input voltage is not determined to be an abnormal voltage (S20: NO), the thermoelectromotive force from the fourth thermocouple 34 is normal. Therefore, in order to end the check of the fourth thermocouple 34 and execute the check of the fifth thermocouple 35, the switching pulse is changed at the timing t7 prior to the timing t8. That is, the switching pulse of the H signal is output from the switching CH2, and the switching pulse of the L signal is output from the other switching CH1, 3 and 4. As a result, the FET circuit 64 that has been turned on is turned off (S21).

  Next, the fifth thermocouple 35 is checked at timing t8. As shown in FIG. 9, only the FET circuit 65 corresponding to the switching CH2 is reliably turned on (S27). The thermoelectromotive force output from the fifth thermocouple 35 is amplified by the fourth thermocouple input circuit 54 and input to the analog CH 4 of the microcomputer control circuit 50. Here, it is determined whether or not the thermoelectromotive force output from the fifth thermocouple 35 is a misfire voltage (S28). That is, it is determined whether or not the input voltage of the analog CH4 is below a predetermined level stored in the flash memory. If the cock switch 18a corresponding to the grill burners A, B, C, and D is not turned on, it is not determined as a misfire voltage even if the input voltage is below a predetermined level.

  If the thermoelectromotive force output from the fifth thermocouple 35 is determined to be a misfire voltage (S28: YES), the safety valve 41 corresponding to the grill burners A, B, C, D is closed (S31), 4 Two grill burners are extinguished. This can prevent the grill burner B from disappearing.

  Next, it is determined whether or not the ignition button 18 is pressed again and the cock switch 18a is turned on again (S32). While it is not turned on again (S32: NO), the process returns to S32 and the depression of the ignition button 18 is monitored. If it is determined that the ignition button 18 has been pressed again (S32: YES), the safety valve 41 is opened (S33), the process returns to S18, and the grill side TC check process is executed from the beginning.

  By the way, when the input voltage is not determined to be a misfire voltage (S28: NO), it is determined whether the thermoelectromotive force is an abnormal voltage (S29). Here, it is determined whether or not the input voltage exceeds the upper limit value of the allowable range stored in the flash memory. When the upper limit of the allowable range is exceeded (S29: YES), an abnormality of the grill burner B, an abnormality of the fifth thermocouple 35, an abnormality of the fourth thermocouple input circuit 54, and the like are conceivable. In this state, the combustion state of the grill burner B cannot be accurately detected. In this case, the safety valve 41 corresponding to the grill burners A to D is closed (S34), and the grill burners A to D are extinguished. Then, without interlocking with the operation of the ignition button 18, the processing ends with the safety valve 41 being closed. That is, by preventing reignition, it is possible to prevent a new combustion trouble or the like from being induced.

  On the other hand, when the input voltage is not determined to be an abnormal voltage (S29: NO), the thermoelectromotive force from the fifth thermocouple 35 is normal. Therefore, in order to end the check of the fifth thermocouple 35 and execute the check of the sixth thermocouple 36, the switching pulse is changed at the timing t9 prior to the timing t10. That is, the switching pulse of the H signal is output from the switching CH3, and the switching pulse of the L signal is output from the other switching CH1, 2, and 4. As a result, the FET circuit 65 that was turned on is turned off (S30).

  Next, the sixth thermocouple 36 is checked at timing t10. As shown in FIG. 10, only the FET circuit 66 corresponding to the switching CH3 is reliably turned on (S36). The thermoelectromotive force output from the sixth thermocouple 36 is amplified by the fourth thermocouple input circuit 54 and input to the analog CH 4 of the microcomputer control circuit 50. Here, it is determined whether or not the thermoelectromotive force output from the sixth thermocouple 36 is a misfire voltage (S37). That is, it is determined whether or not the input voltage of the analog CH4 is below a predetermined level stored in the flash memory. If the cock switch 18a corresponding to the grill burners A, B, C, and D is not turned on, it is not determined as a misfire voltage even if the input voltage is below a predetermined level.

  If the thermoelectromotive force output from the sixth thermocouple 36 is determined to be a misfire voltage (S37: YES), the safety valve 41 corresponding to the grill burners A, B, C, D is closed (S40), 4 Two grill burners are extinguished. This can prevent the grill burner C from disappearing.

  Next, it is determined whether or not the ignition button 18 is pressed again and the cock switch 18a is turned on again (S41). While it is not turned on again (S41: NO), the process returns to S41 and the depression of the ignition button 18 is monitored. If it is determined that the ignition button 18 has been pressed again (S41: YES), the safety valve 41 is opened (S42), the process returns to S18, and the grill side TC check process is executed from the beginning.

  By the way, when the input voltage is not determined to be a misfire voltage (S37: NO), it is determined whether or not the thermoelectromotive force is an abnormal voltage (S38). Here, it is determined whether or not the input voltage exceeds the upper limit value of the allowable range stored in the flash memory. When the upper limit of the allowable range is exceeded (S38: YES), an abnormality of the grill burner C, an abnormality of the sixth thermocouple 36, an abnormality of the fourth thermocouple input circuit 54, and the like are conceivable. In this state, the combustion state of the grill burner C cannot be accurately detected. In this case, the safety valve 41 corresponding to the grill burners A to D is closed (S43), and the grill burners A to D are extinguished. Then, without interlocking with the operation of the ignition button 18, the processing ends with the safety valve 41 being closed. That is, by preventing reignition, it is possible to prevent a new combustion trouble or the like from being induced.

  On the other hand, when the input voltage is not determined to be an abnormal voltage (S38: NO), the thermoelectromotive force from the sixth thermocouple 36 is normal. Therefore, in order to end the check of the sixth thermocouple 36 and execute the check of the seventh thermocouple 37, the switching pulse is changed at the timing t11 prior to the timing t12. That is, the switching pulse of the H signal is output from the switching CH4, and the switching pulse of the L signal is output from the other switching CH1 to CH3. As a result, the FET circuit 66 that was turned on is turned off (S39).

  Next, at the timing t12, the seventh thermocouple 37 is checked. As shown in FIG. 11, only the FET circuit 67 corresponding to the switching CH4 is reliably turned on (S45). The thermoelectromotive force output from the seventh thermocouple 37 is amplified by the fourth thermocouple input circuit 54 and input to the analog CH 4 of the microcomputer control circuit 50. Here, it is determined whether or not the thermoelectromotive force output from the seventh thermocouple 37 is a misfire voltage (S46). That is, it is determined whether or not the input voltage of the analog CH4 is below a predetermined level stored in the flash memory. If the cock switch 18a corresponding to the grill burners A, B, C, and D is not turned on, it is not determined as a misfire voltage even if the input voltage is below a predetermined level.

  If it is determined that the thermoelectromotive force output from the seventh thermocouple 37 is a misfire voltage (S46: YES), the safety valve 41 corresponding to the grill burners A, B, C, D is closed (S49), 4 Two grill burners are extinguished. This can prevent the grill burner D from disappearing.

  Next, it is determined whether or not the ignition button 18 is pressed again and the cock switch 18a is turned on again (S50). While it is not turned on again (S50: NO), the process returns to S50 and the depression of the ignition button 18 is monitored. If it is determined that the ignition button 18 has been pressed again (S50: YES), the safety valve 41 is opened (S51), the process returns to S18, and the grill side TC check process is executed from the beginning.

  By the way, when the input voltage is not determined to be a misfire voltage (S46: NO), it is determined whether or not the thermoelectromotive force is an abnormal voltage (S47). Here, it is determined whether or not the input voltage exceeds the upper limit value of the allowable range stored in the flash memory. When the upper limit of the allowable range is exceeded (S47: YES), an abnormality of the grill burner D, an abnormality of the seventh thermocouple 37, an abnormality of the fourth thermocouple input circuit 54, and the like are conceivable. In this state, the combustion state of the grill burner D cannot be accurately detected. In this case, the safety valve 41 corresponding to the grill burners A to D is closed (S52), and the grill burners A to D are extinguished. Then, without interlocking with the operation of the ignition button 18, the processing ends with the safety valve 41 being closed. That is, by preventing reignition, it is possible to prevent a new combustion trouble or the like from being induced.

  On the other hand, when the input voltage is not determined to be an abnormal voltage (S47: NO), the thermoelectromotive force from the seventh thermocouple 37 is normal. Therefore, in order to end the check of the seventh thermocouple 37 and shift to the next stove side TC check process, the switching pulse output from the switching CH4 is set to the L signal and turned on at the timing t0. The FET circuits 64 to 67 are turned off (S48). Next, the check of the seventh thermocouple 37 is completed, and the process returns to the flowchart of FIG. 5 to determine whether or not the ignition buttons 15 to 18 are pressed again and all the cock switches 15a to 18a are turned off (S5). ). When any of the cock switches 15a to 18a is turned on and cooking is being performed (S5: NO), the process returns to S2 and the above process is repeated. On the other hand, when it is determined that all of the cock switches 15a to 18a are turned off (S5: YES), the process ends.

  In the above description, the built-in stove 1 shown in FIG. 1 is the “gas heating cooker” of the present invention, and the FET circuits 64 to 67 shown in FIG. 3 correspond to the “switching circuit” of the present invention. The pair input circuit 54 corresponds to the “input circuit” of the present invention, the microcomputer control circuit 50 corresponds to the “control circuit” of the present invention, and the analog CH1 to CH4 shown in FIG. 4 correspond to the “input terminal” of the present invention. To do. Further, the CPU of the microcomputer control circuit 50 that executes the process of S16 in the flowchart of FIG. 7 corresponds to the “confirming means” of the present invention, and the CPU of the microcomputer control circuit 50 that executes the process of S17 corresponds to the “valve closing” of the present invention. It corresponds to “instruction means”.

  As described above, in the built-in stove 1 of the present embodiment, the fourth thermocouple 34 to the seventh thermocouple 37 provided in the grill are connected to the FET circuits 64 to 67, respectively. Switch timings of the FET circuits 64 to 67 are controlled by the microcomputer control circuit 50. Therefore, the four thermoelectromotive forces output from the fourth thermocouple 34 to the seventh thermocouple 37 are sequentially read one by one, amplified by the fourth thermocouple input circuit 54, and converted to analog CH 4 of the microcomputer control circuit 50. Can be entered sequentially. That is, since a plurality of thermoelectromotive forces output from a plurality of thermocouples can be input to one analog CH4 of the microcomputer control circuit 50, another analog CH can be used for another analog input. Moreover, since four thermoelectromotive forces can be read one by one in order, it can respond only by the 4th thermocouple input circuit 54. FIG. As a result, the circuit configuration on the electrical board 70 can be simplified. Furthermore, since the number of thermocouple input circuits can be reduced relative to the number of thermocouples, the cost can be reduced.

  Further, a zero check process for checking the thermoelectromotive force from each thermocouple is performed in a state where all the FET circuits 64 to 67 are turned off. If an abnormal voltage is detected from the thermocouple with all of the FET circuits 64 to 67 turned off, a failure of the FET circuits 64 to 67 is considered, so the safety valve is closed and forcibly terminated. Thereby, the safe built-in stove 1 can be provided.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the analog inputs of the first thermocouple 31 to the third thermocouple 33 installed in the standard burner 5, the high thermal power burner 6, and the firewood burner 7 may be time-division controlled using an FET circuit. In addition, analog inputs of all thermocouples may be time-division controlled using FET circuits.

  Further, the number of grill burners in the grill cabinet is not limited to the above embodiment.

  The gas cooking device of the present invention can be applied to a gas cooking device including a plurality of thermocouples in order to detect misfire in a plurality of burners.

It is a perspective view of built-in stove 1. It is a top view of built-in stove 1. FIG. It is a block diagram which shows the electrical structure of the built-in stove. It is a timing chart of the thermocouple check process by CPU. It is a main flowchart of the thermocouple check process by CPU. 6 is a flowchart of a stove side TC check process shown in FIG. 5. It is a flowchart of the zero check process shown in FIG. It is a flowchart of the grille side TC check process shown in FIG. It is a flowchart which shows the continuation of FIG. 10 is a flowchart showing a continuation of FIG. 9. It is a flowchart which shows the continuation of FIG.

1 Built-in stove 34 4th thermocouple 35 5th thermocouple 36 6th thermocouple 37 7th thermocouple 38 safety valve 39 safety valve 40 safety valve 41 safety valve 50 microcomputer control circuit 54 4th thermocouple input circuit 64 FET circuit 65 FET circuit 66 FET Circuit 67 FET circuit A to D Grill burner

Claims (2)

A plurality of burners, a solenoid valve for controlling fuel supply to the plurality of burners, a plurality of thermocouples provided corresponding to the plurality of burners and detecting flames of the burners, and the plurality of thermocouples A gas heating cooker comprising a control circuit for controlling the driving of the solenoid valve based on voltage signals respectively output from
A plurality of switching circuits which are respectively connected corresponding to the plurality of thermocouples, and which turn on and off voltage signals output from the thermocouples;
The switching pulses for switching the switch timings of the plurality of switching circuits are output to the plurality of switching circuits, respectively, and the output of the switching pulse is changed, so that the switching circuits output the plurality of thermocouples, respectively. Switch control means for sequentially switching on / off of each voltage signal ;
Connected to the plurality of switching circuits, the switching control means in response to an output of the switching pulse is output, and amplifies the respective voltage signals of the plurality of thermocouples that will be sequentially output from said plurality of switching circuits And an input circuit for sequentially inputting to the input terminal of the control circuit ,
The switch control means includes
Provide a predetermined pause period immediately before switching the switch timing,
In the pause period, the gas heating cooker is characterized by changing the output of the switching pulse prior to the switching timing . Confirming means for confirming whether or not all the voltage signals input from the input circuit are equal to or lower than a predetermined value in a state where the plurality of switching circuits are turned off,
A valve closing instruction means for instructing to forcibly close the electromagnetic valve when it is determined by the confirmation means that any of the voltage signals input from the input circuit is not less than a predetermined value; The gas heating cooker according to claim 1, further comprising:

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