JP5105946B2 - Cooking equipment - Google Patents

Description

  The present invention relates to a cooking device, and more particularly to a cooking device provided with a temperature detection means for detecting the temperature of the bottom surface of a cooking container.

Conventionally, in order to prevent a tempura fire or the like, the bottom temperature of the cooking container heated by the heating means such as a gas burner is detected by the temperature detecting means, and when the detected temperature reaches a set temperature, the heating by the heating means is stopped. A cooking device is known. In this heating cooking apparatus, a temperature sensor with a built-in thermistor is brought into contact with the bottom surface of the cooking container placed on Gotoku. The temperature detected by the thermistor is monitored, and when the detected temperature reaches the set temperature, the electromagnetic valve provided in the gas supply path to the burner is forcibly closed to automatically digest. In order to detect a short-circuit failure of the thermistor, a cooking device in which a current fuse is connected in series with the thermistor has been proposed (see, for example, Patent Document 1). According to this cooking device, when the thermistor is short-circuited, the current fuse is blown to detect a failure. There has also been proposed a cooking device that detects a disconnection failure when the electrical resistance of the thermistor exceeds a predetermined value (see, for example, Patent Document 2).
JP-A-9-33047 JP-A-9-210808

  However, in such a conventional cooking device, the only way to detect a thermistor failure is to detect an extreme failure such as a short-circuit failure and a disconnection failure, and it is not possible to detect the failure by grasping the error in the detected temperature. There was a problem that it was not possible. For this reason, there was a concern that automatic fire extinguishing would not be performed even though the set temperature was actually reached.

  The present invention has been made to solve the above-described problems, and provides a cooking device that can detect an error in the temperature detected by the temperature detecting means and detect a failure of the temperature detecting means more accurately. With the goal.

In order to achieve the above object, a heating cooking apparatus according to a first aspect of the present invention comprises a heating means for heating an object to be cooked, and a thermistor for detecting the temperature of the object to be cooked heated by the heating means. A heating cooking device, wherein at least one of a state of a switch that gives an instruction to switch between the operation and stop of the heating means, and an output of a thermocouple that detects whether or not the heating means is operating A heating state determination unit that determines whether or not heating by the heating unit is being performed, a time measurement unit that measures a predetermined time, and a determination that heating by the heating unit is being performed by the heating state determination unit A failure detecting means for determining that the thermistor has failed when a temperature rise during a predetermined time measured by the time measuring means is within a predetermined range. If the temperature detected by the thermistor is 60 ° C. to 80 ° C., and a failure detection operation execution control means for executing the operation by the failure detecting means.

  In the cooking device of the invention according to the present invention, when heating by the heating means is performed, it is determined whether or not the rise value during a predetermined time of the temperature detected by the thermistor is outside a predetermined range. Thermistor failure can be detected. As a result, not only an extreme failure of the thermistor such as a short-circuit failure and a disconnection failure, but also a shift in the detected temperature can be grasped, so that the failure of the thermistor can be detected more accurately.

In addition, since the operation by the failure detection means is executed when the temperature detected by the thermistor is 60 ° C. to 80 ° C., it is possible to reduce the influence of variations in temperature rise gradient due to different temperature zones. Therefore, not only when the thermistor is cooled to about room temperature but also when the thermistor is not sufficiently cooled due to the effect of the previous heating, the failure of the thermistor can be accurately detected.

  Whether the heating means is heated by at least one of the state of a switch that gives an instruction to switch the heating means between operation and stop and the output of a thermocouple that detects whether the heating means is operating or not. It is possible to easily determine whether or not.

  Hereinafter, a stove 1 according to an embodiment of the present invention will be described with reference to the drawings. 1 is a plan view of the stove 1, FIG. 2 is a front view of the stove 1, and FIG. 3 is a block diagram showing an electrical configuration of the stove 1. As shown in FIG. FIG. 4 is a diagram showing an example in which the detected temperature of the normal first thermistor 7 is compared with the detected temperature of the first thermistor 7 in which a failure has occurred, and FIG. 5 shows the thermistor by the microcomputer control circuit 40. It is a flowchart which shows a failure detection process.

  The stove 1 according to the present embodiment calculates and calculates the temperature that rises within a predetermined time when the burner is in a heated state and the temperature detected by the thermistors 7 and 8 indicates a specific temperature range. If the temperature rise is within a predetermined range, it is determined that the thermistors 7 and 8 are out of order. Thereby, the failure of the thermistors 7 and 8 can be accurately detected.

  First, a schematic configuration of the stove 1 will be described. As shown in FIGS. 1 and 2, a top plate 2 having a substantially rectangular plate shape is provided on the top surface of the stove 1, and a circular opening 3 is formed in a right half portion of the top plate 2. A circular opening 4 is formed in the left half portion. A standard burner 5 is provided inside the opening 4, and a strong heating power burner 6 is provided inside the opening 3. The openings 4 and 3 are provided with virtues 11 and 12 so as to cover the outer peripheries of the standard burner 5 and the high heat burner 6, and cooking pots (not shown) are placed on the upper portions of the virtues 11 and 12. Placed.

  In addition, thermocouples 19 and 20 are provided in the vicinity of the standard burner 5 and the high thermal power burner 6 to detect that the burners 5 and 6 are in a combustion state by generating an electromotive force by heating the combustion flame. To do. A first thermistor 7 is provided at the center of the standard burner 5, and a second thermistor 8 is provided at the center of the high thermal power burner 6. These thermistors 7 and 8 detect the bottom temperature of the pot by abutting against the bottom of the cooking pot placed on the virtues 11 and 12. That is, since the temperature of the cooking object in the cooking pan cannot be directly detected, the temperature of the cooking object in the cooking pan is estimated by detecting the pan bottom temperature. In addition, a grill 15 is provided in the center of the inside of the stove 1, and a grill burner (not shown) for heating an object to be cooked is provided in a grill box (not shown) of the grill 15.

  Further, an exhaust port (not shown) of the grill 15 is provided behind the top plate 2, and exhaust port covers 13 and 14 for blocking the rise of flame from the grill exhaust port are provided at the grill exhaust port. It is detachable. The exhaust port covers 13 and 14 are provided with a plurality of exhaust holes 13a and 14a, respectively.

  As shown in FIG. 2, an operation switch 21 for igniting the standard burner 5 is provided on the lower left side of the front surface facing the user of the stove 1. In addition, an operation switch 22 for igniting the high thermal power burner 6 and an operation switch 23 for igniting the grill burner (not shown) are provided side by side at the lower part on the right side across the grill 15. Further, a heating power adjustment lever 25 capable of manually adjusting the heating power of the standard burner 5 is provided above the operation switch 21, and a heating power adjustment lever capable of manually adjusting the heating power of the strong heating power burner 6 is provided above the operation switch 22. 26 is provided, and on the upper side of the operation switch 23, a heating power adjusting lever 27 capable of manually adjusting the heating power of the grill burner (not shown) is provided. In addition, a battery box 29 in which a dry battery is installed and a speaker 50 (see FIG. 3) for sounding a buzzer are provided at the left end of the front surface of the stove 1.

  Further, the standard burner 5, the strong burner 6, and the grill burner of the stove 1 are each provided with an igniter 35 (see FIG. 3) for igniting each burner. Further, the stove 1 is provided with a safety valve 38 (see FIG. 3), which is an electromagnetic valve for shutting off the gas supply when a failure of the thermistors 7 and 8 is detected. 1 and 2 correspond to the “heating means” of the present invention, and the first thermistor 7 and the second thermistor 8 correspond to the “temperature detection means”.

  Next, the electrical configuration of the stove 1 will be described. As shown in FIG. 3, the stove 1 includes a microcomputer control circuit 40 that performs thermal power control of various burners. The microcomputer control circuit 40 includes a CPU 40a, a ROM 40b, a RAM 40c, an I / O interface (not shown), and the like. The microcomputer control circuit 40 includes a power supply circuit 41 that supplies power to various circuits by a dry battery mounted in the battery box 29 (see FIG. 2), and switches that detect pressing of the operation switches 21, 22, and 23, respectively. An input circuit 42, a thermistor input circuit 43 for inputting detection signals output from the thermistors 7 and 8, an igniter circuit 45 for driving the igniters 35 of various burners, and a safety valve for controlling the opening and closing of each safety valve 38 A circuit 46, a thermocouple circuit 51 for detecting the electromotive force of the thermocouples 19 and 20, a voltage monitoring circuit 47 for monitoring the voltage of the power supplied from the power supply circuit 41, and a buzzer for outputting a buzzer from the speaker 50. Non-volatile memory circuit 4 which is a semiconductor memory capable of retaining stored contents even when power from output circuit 48 and power supply circuit 41 is cut off If, like are respectively connected. The power supply circuit 41 includes a microcomputer control circuit 40, a switch input circuit 42, a thermistor input circuit 43, an igniter circuit 45, a safety valve circuit 46, a thermocouple circuit 51, a voltage monitoring circuit 47, a buzzer output circuit 48, and a nonvolatile memory circuit 49. Are connected to each other to supply power to each circuit.

  Next, a failure detection method for the thermistors 7 and 8 in the stove 1 will be described. In the example shown in FIG. 4, the detected temperature of the first thermistor 7 operating normally and the detected temperature of the first thermistor 7 in which the detected temperature becomes lower than the actual temperature as the temperature zone becomes higher are generated. An example is compared. The failure of the first thermistor 7 in this case is not an extreme failure such as a short-circuit failure or a disconnection failure, but a temperature different from the actual temperature due to a slight change in the electric resistance value due to the influence of circuit modification or the like. It is a detected fault.

  As shown in FIG. 4, when the standard burner 5 is ignited (time “0”), the detected temperature rises due to the heating of the standard burner 5 over time. However, the higher the temperature zone with time, the lower the failure detection temperature than the normal detection temperature. That is, the rising gradient of the detected temperature by the first thermistor 7 in which a failure has occurred is smaller than the rising gradient of the detected temperature by the normal first thermistor 7. Therefore, in the present embodiment, the temperature rise during a predetermined time (for example, 10 seconds) by the first thermistor 7 is calculated in a state where the standard burner 5 is ignited. If the calculated temperature rise is within a predetermined range (for example, 10 ° C. or less), it is determined that the first thermistor 7 has failed. Further, even if the temperature is detected by the same thermistor, the temperature increase gradient varies depending on the temperature zone. Therefore, the variation of the temperature increase gradient is reduced by setting the temperature zone where the failure detection is performed as a specific temperature zone. Since the failure detection method of the second thermistor 8 is the same as the failure detection method of the first thermistor 7, this description is omitted.

  Next, the thermistor failure detection process will be described. In the present embodiment, since the same failure detection process is executed for the two thermistors 7, 8, the process for the first thermistor 7 will be described below. As shown in FIG. 5, when power supply to the microcomputer control circuit 40 is started by the power supply circuit 41, the thermistor failure detection process by the CPU 40a of the microcomputer control circuit 40 is started. First, it is determined whether or not the standard burner 5 is in an ignition state (S1). This determination is made based on whether or not the operation switch 21 is on. If the operation switch 21 is off and it is determined that the standard burner 5 is not in the ignition state (S1: NO), the ignition is performed. This determination is repeated until a state is reached.

  If it is determined that the operation switch 21 is on and the standard burner 5 is in an ignition state (S1: YES), whether or not the temperature detected by the first thermistor 7 is 60 ° C. to 80 ° C. Is determined (S2). That is, when the detected temperature is about room temperature at the time of determination of S1, it is determined whether or not the detected temperature reaches 60 ° C., and the first thermistor 7 is sufficiently cooled by the influence of the previous combustion at the time of determination of S1. If not, it is determined whether or not the detected temperature is in a temperature range of 60 ° C to 80 ° C. In the present embodiment, failure detection is performed only when the detected temperature is 60 ° C. to 80 ° C. Therefore, when the detected temperature is not 60 ° C. to 80 ° C. (S2: NO), the process returns to the determination of S1. On the other hand, when the temperature detected by the first thermistor 7 is 60 ° C. to 80 ° C. (S2: YES), the temperature detected by the first thermistor 7 at that time is stored in the RAM 40c of the microcomputer control circuit 40. (S3). And the process which starts the measurement by the timer for the predetermined time (for example, 10 seconds) until it judges whether it has failed is performed (S4).

  Next, it is determined whether or not the standard burner 5 is in an ignition state (S5). If it is determined that the standard burner 5 is not in an ignition state during the measurement of the timer (S5: NO), the process returns to S1 without determining whether or not a failure has occurred. When it is determined that the standard burner 5 is in the ignition state (S5: YES), it is determined whether or not the measurement of the predetermined time by the timer has ended (S6). If measurement is in progress (S6: NO), the determination as to whether or not the standard burner 5 is in an ignition state (S5) and the determination as to whether or not the timer has ended (S6) are repeated.

  When the measurement for the predetermined time is completed (S6: YES), a value obtained by subtracting the stored temperature detected at the start of the measurement for the predetermined time from the current temperature detected by the first thermistor 7 is calculated. Whether or not this value is within a predetermined range (for example, 10 ° C. or less) is determined (S7). When it is outside the predetermined range (S7: NO), it is determined that the first thermistor 7 is normal, and the process returns to the determination of S1 as it is. On the other hand, if the calculated difference is within the predetermined range (S7: YES), the failure of the first thermistor 7 is stored in the nonvolatile memory circuit 49 (S8), and the process returns to the determination of S1. When a failure of the first thermistor 7 is detected, a buzzer is generated from the speaker 50 and a process for closing the safety valve 38 is performed to cut off the gas supply to the standard burner 5.

  In S1 and S5 of the flowchart shown in FIG. 5, the CPU 40a of the microcomputer control circuit 40 that determines whether the heating by the standard burner 5 is performed functions as the “heating state determining means” of the present invention, and S6. The CPU 40a that determines whether or not the timer set in S4 has ended functions as a "time measuring means". In S7, the CPU 40a that detects the failure of the first thermistor 7 functions as “failure detection means” by determining whether or not the temperature that has risen within the predetermined time is within a predetermined range. In S <b> 2, the CPU 40 a that executes failure detection when the temperature detected by the first thermistor 7 is in a specific temperature range functions as “failure detection operation execution control means”. Although not shown in FIG. 5, the thermistor failure detection process of the present embodiment is executed when the thermal power adjusting lever 25 detects that the thermal power by the burner is equal to or greater than a predetermined value.

  As described above, in the stove 1 of the present embodiment, the temperature rise during the predetermined time by the thermistors 7 and 8 is calculated with the burners 5 and 6 being lit. Then, a failure of the thermistors 7 and 8 is detected by determining whether or not the calculated increased temperature is within a predetermined range. Thereby, it is possible to detect a failure of the thermistors 7 and 8 other than a short-circuit failure or a disconnection failure, which is a failure in which a temperature different from the actual temperature is detected by changing the electric resistance value. Further, by setting the temperature zone where failure detection is performed as a specific temperature zone, it is possible to detect the failure of the thermistors 7 and 8 more accurately by reducing variations in the temperature rising gradient.

  In addition, the cooking apparatus of this invention is not limited to the stove 1 of the said embodiment, A various change is possible. First, in the present embodiment, the ignition state of the burners 5 and 6 is determined by turning on and off the operation switches 21 and 22, but the ignition state is determined depending on whether or not an electromotive force is generated by the thermocouples 19 and 20. The determination may be made using both the electromotive force of the thermocouples 19 and 20 and the on / off of the operation switches 21 and 22. In addition, the temperature range in which the failure detection operation is performed, the length of time measured by the timer, the range of the temperature difference serving as a reference for determining the failure, and the like may be set as appropriate. For example, it is possible to change the range of the temperature difference serving as a criterion for failure determination according to the strength of the thermal power detected by the thermal power control levers 25 and 26 and the like. Further, the failure detection may be performed by combining the failure detection method of the thermistor according to the present invention with the conventional failure detection method of detecting a short circuit failure or a disconnection failure.

  The heating cooking apparatus of the present invention is applicable to a heating cooking apparatus that includes a thermistor capable of measuring the heating temperature of an object to be cooked and controls the combustion flame by a burner based on the temperature detected by the thermistor.

1 is a plan view of a stove 1. FIG. It is a front view of the stove 1. It is a block diagram which shows the electric constitution of the stove. It is a figure which shows an example which compared the detection temperature of the normal 1st thermistor 7 with the detection temperature of the 1st thermistor 7 in which the failure has occurred. 4 is a flowchart showing a thermistor failure detection process by a microcomputer control circuit 40.

1 Stove 5 Standard Burner 6 High Thermal Burner 7 First Thermistor 8 Second Thermistor 19, 20 Thermocouple 21, 22 Operation Switch 40 Microcomputer Control Circuit 40a CPU

Claims (1)

A heating cooking apparatus comprising a heating means for heating a cooking object, and a thermistor for detecting the temperature of the cooking object heated by the heating means,
Heating by the heating means is performed by at least one of the state of a switch that gives an instruction to switch between the operation and stop of the heating means and the output of a thermocouple that detects whether or not the heating means is operating. Heating state determination means for determining whether or not
A time measuring means for measuring a predetermined time;
If the heating state determining means determines that the heating means is heating, and if the temperature rise during the predetermined time measured by the time measuring means is within a predetermined range, the thermistor fails. Failure detection means for determining that
A heating cooking apparatus, comprising: a failure detection operation execution control unit configured to execute an operation by the failure detection unit when a temperature detected by the thermistor is 60 ° C. to 80 ° C.

Images