JP5160183B2 - Gas cooker - Google Patents

Description

  The present invention relates to a gas cooking device, and more particularly, to a gas cooking device provided with a thermistor that detects the bottom temperature of a cooking pan for each of a plurality of burners.

Conventionally, in order to prevent a tempura fire or the like, a temperature sensor detects the bottom temperature of a cooking pan heated by a heating means such as a burner, and when the detected temperature reaches a set temperature, a gas that stops heating by the burner Cookers are known. For example, automatically distinguishing between water and oil dishes, automatically setting an appropriate fire extinguishing temperature according to the dish, and heating that automatically extinguishes when the temperature detected by the temperature detector reaches the set temperature. A cooking apparatus is known (see, for example, Patent Document 1). In this type of gas stove, a temperature sensor with a built-in thermistor is brought into contact with the bottom surface of the cooking container placed on the virtues. An analog signal (voltage signal) output from the thermistor is input to the input terminal of the control circuit. In the control circuit, if the value input to the input terminal is less than a predetermined threshold value, the burner combustion is continued. If it is equal to or greater than the threshold value, the cooking pan is at an abnormally high temperature, so the solenoid valve is closed and combustion of the burner is stopped. As a result, it is possible to prevent the object to be cooked from burning and oil fires.
JP-A-6-129648

  However, in such a gas cooking device, there are numerical limitations on the input terminal of the control circuit. In addition to the thermistor, a plurality of input terminals provided in the control circuit are connected to a voltage monitoring circuit, a thermocouple input circuit for detecting a burner misfire, and the like. Recently, gas stoves each having a thermistor in a plurality of stove burners are also known, and the number of input terminals required for the control circuit tends to increase. Therefore, it is necessary to take measures by selecting a control circuit having a higher specification and having more input terminals than the prior art, or by providing a comparison element such as a comparator outside, which has been a cause of cost increase. Furthermore, since an input circuit for inputting a voltage signal from the thermistor must be provided corresponding to the number of thermistors, there is 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 voltage signals from a plurality of thermistors to a control circuit. With the goal.

In order to achieve the above object, a gas cooking device of the invention according to claim 1 corresponds to a plurality of burners, a plurality of solenoid valves for controlling fuel supply to the plurality of burners, and the plurality of burners. Each of which is provided with a plurality of thermistors for detecting the bottom temperature, and a control circuit for controlling the driving of the plurality of solenoid valves based on voltage signals respectively output from the plurality of thermistors. A plurality of switching circuits which are respectively connected to the plurality of thermistors and which turn on and off voltage signals output from the thermistors, and a switching pulse which switches switch timings of the plurality of switching circuits. Each of the plurality of switching circuits in the plurality of switching circuits by changing the output of the switching pulse. A switch control means for switching on and off the order of the voltage signals are respectively output from the thermistor is connected to said plurality of switching circuits, in response to the output of the switching pulse the switch control means outputs said plurality of switching circuits and an input circuit that sequentially input to the input terminal of the control circuit of the voltage signal of the plurality of thermistor that will be each sequentially output from said switch control means, the switching predetermined rest period immediately before the switching 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 equal to or less than a predetermined value, and when the confirmation means determines that any of the voltage signals input from the input circuit is not equal to or less than the predetermined value, all the solenoid valves Forcibly closing instruction means for instructing to forcibly close the valve.

  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 thermistors. That is, by controlling on / off of each switching circuit connected to each of the plurality of thermistors, a plurality of voltage signals respectively output from the plurality of thermistors can be taken out one by one. The voltage signals taken out one by one are sequentially input to the input terminals of the control circuit. Accordingly, a plurality of voltage signals respectively output from the plurality of thermistors can be input to one input terminal of the control circuit, so that the number of input terminals used for the thermistor can be saved. Since the number of input terminals can be saved, the number of thermistors 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 electromotive force of the thermocouple installed in various burners, it has the safety function which detects misfire etc. of various burners rapidly, and forcibly interrupts gas supply.

  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. Behind the standard burner 5 and the high-power burner 6 is provided a back burner 7 for melting fire. A grill exhaust port (not shown) is provided behind the back 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 instrument 2 having these structures, a top plate 3 made of ceramic or glass is provided so that the standard burner 5, the high-power burner 6, the back burner 7, and the grill exhaust port are exposed. ing. On the top surface of the top plate 3, five virtues 5a, 6a, and 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 back burner 7, respectively. ing.

  And in the center of the instrument 2, a grill storage (not shown) which is the main body of the grill is incorporated. 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.

  Further, 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 back burner 7 is provided on the right side thereof. An ignition button 16 for igniting the high-power burner 6 is provided on the right front side of the appliance 2, and an ignition button for igniting a grill burner (not shown) installed in the grill cabinet at 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. A heating power adjustment lever 17b for manually adjusting the heating power of the back burner 7 is provided directly above the ignition button 17 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. A heating power adjustment lever 18b for manually adjusting the heating power of the grill burner is provided immediately above the ignition button 18 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, the strong heating burner 6, the back burner 7, and the grill burner (not shown). 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 back burner 7 is provided with a third thermocouple 31. A thermocouple 33 (see FIG. 3) is provided. The grill burner is provided with a fourth thermocouple 34 (see FIG. 3).

  Further, each burner is provided with a temperature sensor for detecting the bottom temperature of the cooking pot placed on the five virtues 5a, 6a, 7a. Specifically, as shown in FIG. 1, the standard burner 5 is provided with a temperature sensor 23 so that it can be withdrawn upward and downward. The temperature sensor 23 includes a standard thermistor 23a (see FIG. 3). The high thermal power burner 6 is provided with a temperature sensor 24 so as to be able to exit and retreat upward. The temperature sensor 24 incorporates a strong thermal power thermistor 24a (see FIG. 3). A temperature sensor 25 is provided in the back burner 7 so as to be able to exit and withdraw upward. The temperature sensor 25 includes a back thermistor 25a (see FIG. 3).

  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 back burner 7 and a fourth gas supply pipe (not shown) for supplying gas to the grill burner (not shown) are provided. Yes. 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, second, and third gas supply pipes are provided with switching valves 28, 29, and 30 (see FIG. 3) for controlling the gas supply amount and adjusting the heating power, respectively. The switching valves 28, 29, and 30 maintain the heating temperatures by the standard burner 5, the strong heating burner 6, and the inner burner 7 detected by the standard thermistor 23a, the strong thermal power thermistor 24a, and the inner thermistor 25a, respectively, within a predetermined temperature range. Therefore, this is a switching valve for performing a so-called “high cut temperature control” for switching the magnitude of the heating power of the standard burner 5, the strong heating power burner 6, and the back heating burner 7. Adjustment of the switching valves 28, 29, and 30 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 outputs the voltage of the dry battery stored in the battery box 21 (see FIG. 1) from the power supply circuit 43 that supplies various circuits on the electrical board 70 and the cock switches 15a to 18a, respectively. A switch input circuit 44 that inputs an on / off signal, an operation panel communication circuit 46 that communicates with the operation panel 20, an igniter circuit 47 that drives the igniter 27, and three switching valves 28 to 30 are driven. A switching valve circuit 48 and a safety valve circuit 49 for driving the four safety valves 38 to 41 are connected to each other.

  The microcomputer control circuit 50 is provided with eight analog channels for analog input (hereinafter referred to as analog CH). Four of the analog CHs are used for the thermocouple analog input, and one analog CH (see FIG. 4) is used for the thermistor analog input. A first thermocouple input circuit 51 that amplifies and inputs an electromotive force from the first thermocouple 31 of the standard burner 5 and a second thermocouple 32 of the strong heat burner 6 are input to the four analog CHs for thermocouple input. The second thermocouple input circuit 52 for amplifying and inputting the electromotive force from the third thermocouple input circuit 53 for amplifying and inputting the electromotive force from the third thermocouple 33 of the back burner 7, and the grill burner first A fourth thermocouple input circuit 54 for amplifying and inputting the electromotive forces from the four thermocouples 34 one by one is connected.

  On the other hand, one thermistor input circuit 56 for inputting voltage signals from the standard thermistor 23a, the high thermal power thermistor 24a, and the back thermistor 25a one by one is connected to one analog CH (see FIG. 4) for thermistor input. Yes. The other analog CH is connected to the dry battery voltage from the power supply circuit 43 described above.

  Further, the standard thermistor 23 a, the high thermal power thermistor 24 a, and the back thermistor 25 a are respectively connected to FET circuits 61, 62, and 63 that are switching elements provided on the electrical substrate 70. Specifically, the standard thermistor 23 a is connected to the source side of the FET circuit 61. The high thermal power thermistor 24 a is connected to the source side of the FET circuit 62. The back thermistor 25 a is connected to the source side of the FET circuit 63. Further, the drain side of the FET circuits 61, 62, 63 is connected to the thermistor input circuit 56, and the gate side is connected to the microcomputer control circuit 50. The switch timings of the FET circuits 61, 62, 63 are controlled by the CPU of the microcomputer control circuit 50. As a result, the three voltage signals respectively output from the standard thermistor 23a, the high thermal power thermistor 24a, and the back thermistor 25a are sequentially read one by one. The thermistor input circuit 56 sequentially inputs the analog CH (see FIG. 4) of the microcomputer control circuit 50.

  Next, the automatic fire extinguishing function of various burners by the thermistor will be described. In the standard burner 5, when the detection temperature of the standard thermistor 23a reaches a preset fire extinguishing temperature, the safety valve 38 provided in the first gas supply pipe (not shown) of the standard burner 5 is forcibly closed and automatically Fire is extinguished. In the high thermal power burner 6, when the detected temperature of the strong thermal power thermistor 24a reaches a preset extinguishing temperature, the safety valve 39 provided in the second gas supply pipe (not shown) of the strong thermal power burner 6 is forcibly closed. It is designed to extinguish fire automatically. Furthermore, in the back burner 7, when the detected temperature of the back thermistor 25a reaches a preset fire extinguishing temperature, the safety valve 40 provided in the third gas supply pipe (not shown) of the back burner 7 is forcibly closed. Fire extinguishes automatically. Thereby, in various burners, the burning by overheating of a cooking pot, a tempura fire, etc. can be prevented beforehand. The fire extinguishing temperature of the standard burner 5, the fire extinguishing temperature of the strong burner 6, and the extinguishing temperature of the back burner 7 are respectively stored in the flash memory of the microcomputer control circuit 50 as predetermined voltage values.

  Next, the check timing of the thermistor check process will be described with reference to the timing chart of FIG. FIG. 4 is a timing chart of the thermistor check process by the CPU. In the thermistor check process, voltage signals output from the standard thermistor 23a, the high thermal power thermistor 24a, and the back thermistor 25a are read in order, and an abnormality check is performed to determine whether or not the fire extinguishing temperature has been reached. This thermistor check process is performed at eight timings divided at t0 to t7. One timing unit is 2 (msec). Therefore, one reading cycle is 8 (timing) × 2 (msec) = 16 (msec).

  Then, after a pause period of t0 timing in one reading cycle, zero check processing for detecting an abnormality of the FET circuits 61, 62, 63 is first performed at timing t1. Further, the ON / OFF of the FET circuits 61, 62, and 63 is switched by time division control at timings t2 to t7. As a result, the three voltage signals output from the standard thermistor 23a, the high thermal power thermistor 24a, and the back thermistor 25a can be read and checked one by one.

  Next, a switch timing switching control method for the FET circuits 61, 62, and 63 will be described with reference to FIGS. The microcomputer control circuit 50 includes three switching channels (refer to FIG. 4; hereinafter referred to as switching CH) corresponding to the FET circuits 61, 62, and 63, respectively. The switching CH1 corresponds to the FET circuit 61, the switching CH2 corresponds to the FET circuit 62, and the switching CH3 corresponds to the FET circuit 63. From these three switching CHs, switching pulses for instructing on / off of the FET circuits 61, 62, 63 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 and 3, only the FET circuit 61 corresponding to the switching CH1 is turned on, and the other FET circuits 62 and 63 are turned off. In this case, only the voltage signal of the standard thermistor 23a is read into the analog CH (see FIG. 4) of the microcomputer control circuit 50. Therefore, the three voltage signals output from the standard thermistor 23a, the high thermal power thermistor 24a, and the back thermistor 25a can be read one by one by changing the switching pulse and sequentially switching the FET circuits 61, 62, and 63 on and off. it can.

  Further, in checking the standard thermistor 23a, the high thermal power thermistor 24a, and the back thermistor 25a, 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 t0 to t7, at the timings t3, t5, and t7, the voltage signals of the standard thermistor 23a, the high thermal power thermistor 24a, and the back thermistor 25a are read, and at the timings t2, t4, and t6, 2 ( msec). In this idle period, the switching pulse output is changed prior to the next timing. Thus, since the waveform of the switching pulse is stabilized and then the next timing is reached, the FET circuits 61 to 67 can be reliably turned on and off at the timings t3, t5, and t7. At the timing t0, the output of the switching pulse is changed in order to perform the zero check process at the timing t1. As a result, since the waveform of the switching pulse is stabilized and the timing shifts to the t1 timing, the zero check process can be reliably performed.

  Next, thermistor check processing by the CPU will be described with reference to the timing chart of FIG. 4 and various flowcharts of FIGS. 5 and 6. FIG. 5 is a flowchart of the thermistor check process by the CPU, and FIG. 6 is a flowchart of the zero check process.

  First, as shown in FIG. 5, it is determined whether any of the cock switches 15a to 17a built in the ignition buttons 15 to 17 is turned on (S1). When none of the cock switches 15a to 17a is pressed (S1: NO), none of the standard burner 5, the high thermal power burner 6 and the back burner 7 is ignited. Therefore, returning to S1, the on / off of the cock switches 15a to 17a is continuously monitored. When it is determined that any one of the cock switches 15a to 17a is turned on (S1: YES), a rest period of 2 (msec) starts at timing t0. Here, the output change of the switching pulse is performed prior to the next zero check process at the timing t1. Then, after elapse of the pause period, zero check processing for checking the abnormality of the FET circuits 61, 62, 63 is executed at timing t1 (S2).

  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 almost zero in a state where the FET circuits 61, 62, and 63 are all turned off. That is, if the input voltage to the analog CH is not almost zero, at least one of the FET circuits 61, 62, and 63 has failed. Therefore, following the t0 timing, also at the t1 timing, the switching pulses output from the switching CH1 to 3 are all L signals, and the FET circuits 61, 62, and 63 are all turned off. In a state where the FET circuits 61, 62, 63 are turned off, it is determined whether or not there is an abnormal output from any of the FET circuits 61, 62, 63 in the analog CH for thermistor input (S15). That is, it is determined whether or not an abnormal voltage is output from any of the FET circuits 61, 62, and 63 and input to the analog CH of the microcomputer control circuit 50 via the thermistor input circuit 56.

  If it is determined that the input voltage to the analog CH exceeds a predetermined value (S15: YES), there is a possibility that any of the FET circuits 61, 62, and 63 has failed and is turned on. If the FET circuits 61, 62, 63 fail, the outputs from the standard thermistor 23a, the high thermal power thermistor 24a, and the back thermistor 25a cannot be normally detected. It is dangerous to continue combustion in this state. Therefore, the safety valves 38 to 40 corresponding to the standard burner 5, the strong heating burner 6 and the back burner 7 are closed (S16), and the standard burner 5, the strong heating burner 6 and the back burner 7 are all extinguished. Then, without interlocking with the operation of the ignition buttons 15, 16, and 17, the process ends with the safety valves 38 to 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, if the input voltage is not determined to be an abnormal voltage (S15: NO), since the FET circuits 61, 62, 63 are normal, the zero check process at the timing t1 ends, and the next process is executed. . Subsequently, a rest period of 2 (msec) is set at the timing t2. In this idle period, the switching pulse output is changed prior to the timing t3 when the standard thermistor 23a is checked. 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 and 3 (see FIG. 4). Thereby, since the waveform of the switching pulse is stabilized and the timing shifts to the timing t3, the FET circuits 61, 62, and 63 can be reliably turned on and off.

  Next, at the timing t3, the standard thermistor 23a is checked. First, only the FET circuit 61 corresponding to the switching CH1 is turned on (S3). The voltage signal from the standard thermistor 23 a is input to the thermistor analog CH of the microcomputer control circuit 50 by the thermistor input circuit 56. Here, it is determined whether or not the voltage signal of the detected temperature output from the standard thermistor 23a is equal to or higher than the fire extinguishing temperature (S4).

  When it is determined that the detected temperature voltage signal output from the standard thermistor 23a is equal to or higher than the fire extinguishing temperature (S4: YES), the safety valve 38 corresponding to the standard burner 5 is closed (S13), and the standard burner 5 is extinguished. Is done. Thereby, overheating by the standard burner 5 can be prevented. Next, it is determined whether or not all of the standard burner 5, the high burner 6 and the back burner 7 have been extinguished (S12). If it is determined that all the fire has been extinguished (S12: YES), the process ends. On the other hand, when either the high-burning burner 6 or the back burner 7 is in a combustion state or the standard burner 5 is re-ignited (S12: NO), the process returns to S2 and is executed again from the zero check process. Is done.

  By the way, when the voltage signal of the detected temperature output from the standard thermistor 23a is determined to be lower than the fire extinguishing temperature (S4: NO), the heating state by the standard burner 5 is normal. Therefore, in order to end the check of the standard thermistor 23a and execute the check of the high thermal power thermistor 24a, the switching pulse is changed at the timing t4 prior to the timing t5. 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 and 3 (see FIG. 4). As a result, the FET circuit 61 that has been turned on is turned off (S5).

  Next, at the timing t5, the high thermal power thermistor 24a is checked. Only the FET circuit 62 corresponding to the switching CH2 is reliably turned on (S6). The voltage signal from the high thermal power thermistor 24 a is input to the thermistor analog CH of the microcomputer control circuit 50 by the thermistor input circuit 56. Here, it is determined whether the voltage signal of the detected temperature output from the high thermal power thermistor 24a is equal to or higher than the fire extinguishing temperature (S7).

  When it is determined that the voltage signal of the detected temperature output from the high thermal power thermistor 24a is equal to or higher than the fire extinguishing temperature (S7: YES), the safety valve 39 corresponding to the high thermal power burner 6 is closed (S13), and the high thermal power burner 6 is extinguished. Thereby, the overheating by the strong heat power burner 6 can be prevented. Next, it is determined whether or not all of the standard burner 5, the high burner 6 and the back burner 7 have been extinguished (S12). If it is determined that all the fire has been extinguished (S12: YES), the process ends. On the other hand, if either the standard burner 5 or the back burner 7 is in a combustion state or if the strong burner 6 is re-ignited (S12: NO), the process returns to S2 and is executed again from the zero check process. Is done.

  By the way, when the voltage signal of the detected temperature output from the strong thermal power thermistor 24a is determined to be lower than the fire extinguishing temperature (S7: NO), the heating state by the strong thermal power burner 6 is normal. Therefore, in order to end the check of the high thermal power thermistor 24a and execute the check of the back thermistor 25a, the switching pulse is changed at the timing t6 prior to the timing t7. 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 and 2 (see FIG. 4). As a result, the FET circuit 62 that has been turned on is turned off (S8).

  Next, at the timing t7, the back thermistor 25a is checked. Only the FET circuit 63 corresponding to the switching CH3 is reliably turned on (S9). The voltage signal from the back thermistor 25 a is input to the thermistor analog CH of the microcomputer control circuit 50 by the thermistor input circuit 56. Here, it is determined whether or not the voltage signal of the detected temperature output from the back thermistor 25a is equal to or higher than the fire extinguishing temperature (S10).

  When it is determined that the detected temperature voltage signal output from the back thermistor 25a is equal to or higher than the fire extinguishing temperature (S10: YES), the safety valve 40 corresponding to the back burner 7 is closed (S13), and the back burner 7 is extinguished. Is done. Thereby, the overheating by the back burner 7 can be prevented. Next, it is determined whether or not all of the standard burner 5, the high burner 6 and the back burner 7 have been extinguished (S12). If it is determined that all the fire has been extinguished (S12: YES), the process ends. On the other hand, when either the standard burner 5 or the strong burner 6 is in a combustion state or the back burner 7 is re-ignited (S12: NO), the process returns to S2 and is executed again from the zero check process. Is done.

  By the way, when the voltage signal of the detected temperature output from the back thermistor 25a is determined to be less than the fire extinguishing temperature (S10: NO), the heating temperature by the back burner 7 is normal. Therefore, the check of the back thermistor 25a is terminated, and it is determined whether or not all of the standard burner 5, the strong heating burner 6, and the back burner 7 are extinguished (S12). When either the standard burner 5 or the high-burning power burner 6 is in a combustion state or the back burner 7 is re-ignited (S12: NO), the process returns to S2 and is executed again from the zero check process. On the other hand, when it is determined that all the fires are extinguished (S12: YES), the process ends. Thus, a series of thermistor check processing is completed.

  In the above description, the built-in stove 1 shown in FIG. 1 corresponds to the “gas cooking device” of the present invention, and the FET circuits 61, 62, and 63 shown in FIG. 3 correspond to the “switching circuit” of the present invention. The thermistor input circuit 56 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 CH shown in FIG. 4 corresponds to the “input terminal” of the present invention. . Further, the CPU of the microcomputer control circuit 50 that executes the process of S15 in the flowchart of FIG. 6 corresponds to the “confirming means” of the present invention, and the CPU of the microcomputer control circuit 50 that executes the process of S16 corresponds to the “valve closing” of the present invention. It corresponds to “instruction means”.

  As described above, in the built-in stove 1 according to the present embodiment, the standard thermistor 23a, the strong thermal power thermistor 24a, and the deep thermistor 25a provided in the standard burner 5, the high thermal power burner 6, and the rear burner 7 are the FET circuits 61 and 62. 63, respectively. The switch timing of the FET circuits 61, 62, 63 is controlled by the microcomputer control circuit 50. As a result, the three voltage signals output from the standard thermistor 23 a, the strong thermal power thermistor 24 a, and the back thermistor 25 a can be read one by one in order, and can be sequentially input to the analog CH of the microcomputer control circuit 50 by the thermistor input circuit 56. That is, since a plurality of voltage signals output from a plurality of thermistors can be input to one analog CH of the microcomputer control circuit 50, another analog CH can be used for another analog input. In addition, since the three electromotive forces can be read one by one in order, it is possible to deal with only the thermistor input circuit 56. As a result, the circuit configuration on the electrical board 70 can be simplified. Furthermore, since the number of thermistor input circuits can be reduced relative to the number of thermistors, the cost can be reduced.

  Further, zero check processing for checking voltage signals from the thermistors is performed in a state where the FET circuits 61, 62, and 63 are all turned off. If an abnormal voltage is detected from the thermistor with the FET circuits 61, 62, 63 all turned off, a failure of the FET circuits 61, 62, 63 is considered, so the safety valve is closed and the operation is 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, a grill thermistor may be provided near the communication port between the grill cabinet and the exhaust passage. Then, an FET circuit may be connected to this grill thermistor, and on / off of the FET circuit may be time-division controlled as in the above embodiment.

  In the above embodiment, the time division control is performed by using the FET circuits 61, 62, and 63 for the three analog outputs of the standard thermistor 23a, the strong thermal power thermistor 24a, and the back thermistor 25a. Of these, only two analog outputs may be time-division controlled using an FET circuit.

  Further, in the above embodiment, the built-in stove has been described as an example, but the present invention can also be applied to a table stove.

  The gas cooking device of the present invention can be applied to a gas cooking device including a plurality of thermistors in order to detect the heating temperatures of the 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 thermistor check processing by CPU. It is a flowchart of the thermistor check process by CPU. It is a flowchart of a zero check process.

DESCRIPTION OF SYMBOLS 1 Built-in stove 5 Standard burner 6 Strong thermal burner 7 Back burner 23 Temperature sensor 23a Standard thermistor 24 Temperature sensor 24a High thermal power thermistor 25 Temperature sensor 25a Back thermistor 38 Safety valve 39 Safety valve 40 Safety valve 50 Microcomputer control circuit 56 Thermistor input circuit 61 FET FET circuit 63 FET circuit

Claims (2)

A plurality of burners, a plurality of solenoid valves for controlling fuel supply to the plurality of burners, a plurality of thermistors provided corresponding to the plurality of burners, respectively, for detecting the pan bottom temperature, and the plurality of thermistors, respectively A gas heating cooker comprising a control circuit for controlling driving of the plurality of solenoid valves based on an output voltage signal;
A plurality of switching circuits which are respectively connected corresponding to the plurality of thermistors and which turn on and off the voltage signals output from the thermistors;
The switching pulses for switching the switching timings of the plurality of switching circuits are output to the plurality of switching circuits, respectively, and the outputs of the switching pulses are changed to output the switching thermistors respectively from the plurality of thermistors. Switch control means for sequentially switching on and off the voltage signal ;
Connected to the plurality of switching circuits, wherein in response to an output of the switching pulse, the control circuit the voltage signal of the plurality of thermistor that will be each sequentially output from said plurality of switching circuits in which the switch control means outputs An input circuit for sequentially inputting to the input terminal,
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,
Forced valve closing instruction that instructs all the solenoid valves to be forcibly closed 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: means.

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