JP3698363B2 - Cooker - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a cooking device such as a table stove, and more specifically, a cooking device that detects the pan bottom temperature of a cooked product and stops combustion when a temperature equal to or higher than a predetermined temperature is detected to prevent overheating to prevent a tempura fire or the like. About.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a heating cooker that detects the pan bottom temperature of an object to be cooked by a thermistor and detects in advance that overheating is expected in order to prevent a tempura fire or the like, and stops combustion.
Here, as an example, a heating cooker will be described with reference to FIG.
In this type of heating cooker such as a table stove, the thermistor 2 is provided at the center of the burner head 3 provided in the burner body 4, and the thermistor 2 is provided by being biased upward by a spring (not shown) for cooking. When the pan 1 is placed on the burner body 4, it is brought into contact with the bottom of the pan to detect the pan bottom temperature, and the combustion controller 7 determines whether or not the temperature exceeds the set upper limit temperature by the combustion controller 7. Has already been known which controls the opening and closing of the main electromagnetic valve 5 and the original electromagnetic valve 6 provided in the gas passage.
[0003]
FIG. 3 shows a temperature detection range of a conventional cooking utensil. The characteristic of T2 in the figure shows the relationship between the detected temperature of the thermistor 2 and time, and shows the detected temperature that rises immediately after ignition. The shaded area represents the allowable temperature range in which the combustion of the overheating cooker can be continued. The upper limit temperature of 250 ° C. is set as a temperature limit at which overheating is expected, and combustion is stopped when the detected temperature becomes 250 ° C. or higher.
[0004]
Moreover, -5 degreeC is set as the minimum temperature of a temperature range, The reason for the setting of the minimum temperature is described below.
The reason is that normal temperature detection cannot be performed when a temperature detection unit configured with the thermistor 2 as a temperature detection element fails, so that the cooking device can be safely stopped even in such a case.
The temperature detection by the thermistor 2 is detected with an electrical resistance value corresponding to the temperature, and is generally used in the N.C. T.A. C. In a (Negative Temperature Coefficient) thermistor, its electrical resistance is inversely proportional to the detected temperature, and increases at a low temperature and decreases at a higher temperature.
Therefore, the failure state of the temperature detection unit is to some extent without causing the temperature detection unit to break and the resistance value to be infinitely large, or to have a resistance value that does not become infinite due to water drops or the like. It is conceivable that the resistance value is a large value, or conversely, the resistance value is small due to a short circuit.
[0005]
If the resistance value becomes small due to a short circuit in the detection unit, the temperature is detected higher than the actual temperature, so the instrument is safely stopped before reaching the upper limit temperature.
On the other hand, if the detection unit is disconnected, the resistance value of the thermistor 2 is kept high, and the low temperature determination is continued. If the upper limit temperature is reached, it is determined that there is a disconnection failure. Judgment is made. The disconnection determination is performed when the resistance value of the thermistor 2 is larger than a predetermined level, that is, in terms of the converted temperature, by detecting the disconnection in the combustion controller 7 when a temperature lower than a predetermined lower limit temperature is detected. In this case, the main solenoid valve 5 and the original solenoid valve 6 are immediately closed to stop the combustion.
Therefore, even if the temperature detection unit such as the thermistor 2 as a safety device causes a short circuit or a disconnection failure, the heating cooker can be stopped safely, and the detected temperature of the thermistor 2 is within the above upper and lower temperature ranges. If there is, the cooking controller 7 determines that the cooking utensil is normal and the combustion is continued.
[0006]
[Problems to be solved by the invention]
However, in a conventional cooking device, disconnection determination of the thermistor detection unit or the like may cause inconveniences in use. Because the resistance value above a predetermined level is used as a disconnection judgment, the resistance value of the thermistor increases when it comes into contact with the low temperature of frozen food, and the cooker may not burn due to an incorrect disconnection judgment. Could happen.
FIG. 4 shows the relationship between the temperature range of a conventional cooking utensil and time. The characteristic of T1 in the figure is the detected temperature when frozen food is placed on a heating cooker and heated. For the sake of explanation, the temperature rise characteristic of T1 is shown in a state where combustion is not stopped by detection of the lower limit temperature.
As apparent from the example of FIG. 4, the detected temperature at the start of ignition is below the lower limit temperature of the allowable temperature range indicated by the oblique lines because frozen food is placed, and is determined to be below the lower limit temperature, that is, a disconnection failure. The cooking utensils cannot start burning.
Frozen foods include cooked foods that enter a container, are frozen as they are, and can be eaten just by heating to a fire, such as frozen udon in an aluminum container.
When the whole frozen frozen food is placed on a heating cooker, the thermistor may detect the temperature of the chilled pan bottom and reach a low temperature below a predetermined level.
As a result, the resistance value of the thermistor exceeds the determination level of the disconnection failure and combustion cannot be started, and the frozen food must be thawed by leaving it for a while.
[0007]
In order to prevent such misjudgment, there is also a method of lowering the set lower limit temperature for judging disconnection detection, that is, further increasing the resistance value level of the thermistor and increasing the difference from the resistance value due to frozen food. Although it is conceivable, the judgment value cannot be increased too much for the following reason.
First, when water drops or the like are attached to the disconnection portion and the resistance value is smaller than the disconnection determination resistance value, there is a possibility that the determination is normal without determining the disconnection. If this happens, it will not be possible to detect abnormally high temperatures at all, and combustion will continue without losing its function as a safety device. Therefore, even if water drops adhere, it is necessary to determine that the disconnection is a disconnection, and thus the determination value cannot be increased unnecessarily.
[0008]
Second, the temperature range in which the thermistor 2 can be detected with high accuracy is limited. Therefore, if the temperature range is too wide, the accuracy is impaired. For example, the relationship between temperature and resistance, which is the thermistor characteristic, is shown in FIG. 2 as an example. If a thermistor having the b characteristic whose detection range is shifted to the low temperature side is selected with respect to the thermistor having the a characteristic, The change in resistance value with respect to the temperature in the high temperature range is smaller than the a characteristic. Therefore, the ability to accurately determine and distinguish between a normal temperature and a set upper limit temperature for a high temperature region that should be detected is impaired.
An object of the present invention is to provide a cooking device that solves the above-described problems and that can be safely stopped even when a temperature detection unit fails without causing troubles in cooking frozen food.
[0009]
[Means for Solving the Problems]
The heating cooker according to claim 1 of the present invention for solving the above-described problems is
When the cooking pan is placed, it comes into contact with the bottom of the pan and includes a temperature detection unit that detects the heating temperature of the food based on the electrical resistance value.
The temperature detected by the temperature detection unit is within an allowable temperature range that is equal to or lower than a set upper limit temperature set for preventing overheating and equal to or higher than a set lower limit temperature set for detecting a disconnection failure of the temperature detection unit. In a cooking device that stops combustion when the detected temperature is out of the allowable temperature range,
For a certain period of time immediately after ignition, there is provided disconnection detection canceling means that does not stop combustion even if the detected temperature is less than the set lower limit temperature, and when the frozen food is heated, the detected temperature after the lapse of the certain period of time is set as described above. The gist is that the temperature reaches the lower limit temperature or higher.
[0010]
A heating cooker according to claim 2 of the present invention,
When the cooking pan is placed, it comes into contact with the bottom of the pan and includes a temperature detection unit that detects the heating temperature of the food based on the electrical resistance value.
The temperature detected by the temperature detection unit is within an allowable temperature range that is equal to or lower than a set upper limit temperature set for preventing overheating and equal to or higher than a set lower limit temperature set for detecting a disconnection failure of the temperature detection unit. In a cooking device that stops combustion when the detected temperature is out of the allowable temperature range,
A lower limit temperature switching means for setting the set lower limit temperature immediately after ignition to a level lower than the detection temperature of the frozen food, and then switching to a temperature higher than the level;
For a certain time after ignition, an upper limit temperature switching means for setting the set upper limit temperature for preventing heating to a value higher by a predetermined temperature;
The main point is that
[0011]
A heating cooker according to claim 3 of the present invention,
When the cooking pan is placed, it comes into contact with the bottom of the pan and includes a temperature detection unit that detects the heating temperature of the food based on the electrical resistance value.
The temperature detected by the temperature detection unit is within an allowable temperature range that is equal to or lower than a set upper limit temperature set for preventing overheating and equal to or higher than a set lower limit temperature set for detecting a disconnection failure of the temperature detection unit. In a cooking device that stops combustion when the detected temperature is out of the allowable temperature range,
For a certain period of time after ignition, the heating temperature gradient by the temperature detector is calculated without using the set lower limit temperature for detecting the disconnection failure, and a comparison is made as to whether or not the heating temperature gradient is greater than the set temperature gradient. If the temperature is equal to or lower than the set temperature gradient, the temperature detector is equipped with a temperature gradient monitoring means that determines that the temperature detection unit is disconnected and stops combustion. When the frozen food is heated, the temperature rises with a temperature gradient greater than the set temperature gradient for the predetermined time. The gist is to do so.
[0012]
A heating cooker according to claim 4 of the present invention,
When the cooking pan is placed, it comes into contact with the bottom of the pan and includes a temperature detection unit that detects the heating temperature of the food based on the electrical resistance value.
The temperature detected by the temperature detection unit is within an allowable temperature range that is equal to or lower than a set upper limit temperature set for preventing overheating and equal to or higher than a set lower limit temperature set for detecting a disconnection failure of the temperature detection unit. In a cooking device that stops combustion when the detected temperature is out of the allowable temperature range,
It is monitored whether or not the temperature below the set lower limit temperature has continued for a certain period of time. If the temperature has continued for a certain period of time, it is determined that the temperature detection unit has failed and combustion is stopped. For example, it is provided with a continuation determination means that does not stop the combustion without determining the disconnection failure, and when the frozen food is heated, the duration for which the detected temperature is equal to or higher than the set lower limit temperature is less than the predetermined time. And
[0013]
The cooking device according to claim 5 of the present invention is the cooking device according to claims 1, 3, and 4,
The gist is that the fixed time after ignition includes an upper limit temperature switching means for setting the set upper limit temperature for preventing heating to a value higher by a predetermined temperature.
[0014]
The cooking device according to claim 1 having the above-described configuration does not stop the combustion for a certain time immediately after ignition by the disconnection detection canceling means at the initial stage of ignition even if it is less than the set lower limit temperature set for detecting the disconnection failure.
Therefore, even if frozen frozen food is placed on a heating cooker and ignited, combustion is not stopped. When a certain time has elapsed since the ignition, the temperature of the frozen food of the cooked food is defrosted by heating and the temperature rises. Therefore, even if the determination of whether or not there is a disconnection failure is started, the disconnection failure can be determined without malfunction due to the low temperature of the frozen food.
[0015]
Moreover, the cooking device of Claim 2 switches the level of the setting minimum temperature set for a disconnection failure detection according to the elapsed time after ignition by a minimum temperature switching means. Immediately after ignition, by setting the set lower limit temperature to a level lower than the detected temperature of the frozen food, combustion is not stopped due to the low temperature of the frozen food. Thereafter, the frozen food is heated and the temperature rises, so the level of the set lower limit temperature is switched to a determination level for detecting a disconnection failure that has a certain resistance value due to water drops or the like.
Thus, by setting the lower limit temperature along with the temperature rise due to the heating of the frozen food, it is possible to determine the disconnection failure without malfunction due to the low temperature due to the frozen food.
Also, for a certain period of time immediately after ignition, the set upper limit temperature for preventing overheating is set to a value that is higher by a predetermined temperature, so even if re-ignition is performed in a state where the temperature detection has risen due to residual heat after combustion stops, Don't be.
[0016]
Further, in the heating cooker according to claim 3, the temperature gradient monitoring means calculates a heating temperature gradient by the temperature detection unit for a certain time after ignition, and determines whether or not the heating temperature gradient is larger than the set temperature gradient. If the temperature gradient is equal to or lower than the set temperature gradient, it is determined that the temperature detection unit is disconnected, and combustion is stopped.
Accordingly, the temperature rises due to the heating of the frozen food, and the detected temperature has a temperature gradient. However, the disconnection failure does not detect the temperature increase and does not have a temperature gradient. Immediately after ignition, it is irrelevant to the low temperature level due to frozen food, and the disconnection failure of the temperature detection unit is determined only by whether the temperature gradient due to heating is equal to or higher than the set temperature gradient. The disconnection failure can be determined without
[0017]
In addition, the cooking device according to claim 4 does not determine that the temperature detection unit is disconnected if the temperature below the set lower limit temperature does not continue for a certain time or longer by the continuation determination unit. Therefore, even if frozen food is placed in the middle of combustion heating, combustion will continue if it recovers above the lower limit temperature within a certain period of time, so the frozen food may temporarily cause the detected temperature to fall below the set lower limit temperature. Even if there is, there will be a recovery from the lower limit temperature within a certain period of time, and a disconnection failure can be determined without malfunction due to the low temperature of frozen food.
[0018]
Further, in the heating cooker according to claim 5, since the set upper limit temperature for preventing overheating is set to a value higher by a predetermined temperature for a certain time immediately after ignition, the temperature detection is increased by residual heat after the combustion is stopped. Even if reignition is performed in the state, combustion is not stopped.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of the heating cooker of the present invention will be described below.
FIG. 1 is a schematic view of a heating cooker as one embodiment. The difference between the present embodiment and the conventional example is an abnormal temperature determination unit in the combustion controller 7. In FIG. 1A, the abnormal temperature determination unit of the combustion controller 7a includes an ignition initial determination unit, which corresponds to first to eighth embodiments described later. Further, in FIG. 1A, the abnormal temperature determination unit of the combustion controller 7b is provided with a continuation determination unit, which corresponds to a ninth embodiment described later.
Hereinafter, the first to ninth embodiments will be described based on the flowcharts shown in FIGS. 14 to 21 and the hot water temperature setting ranges shown in FIGS.
The detected temperature characteristics in the drawings of the respective embodiments are the detection of the thermistor 2 when the heating method specified for a normal frozen food is used in which the heat is first set to low heat for 1 minute and then set to high heat unless otherwise specified. The relationship between temperature and time is shown.
In addition, the shaded area shown in the drawings of each embodiment represents a temperature range in which combustion can be continued.
The time displayed in each embodiment is the time from the ignition operation unless otherwise specified.
In the combustion controllers 7a and 7b in the embodiment, the abnormal temperature determination unit that determines and processes information from the temperature detection unit is mainly configured by a microcomputer, but may be configured by a discrete circuit.
[0020]
First, the first embodiment will be described. FIG. 5 shows the detected temperature range as the first embodiment, and FIG. 14 is a flowchart showing the processing of the combustion controller 7a.
When the ignition operation is performed, first, the combustion controller 7a starts monitoring the set upper limit temperature whether or not the detected temperature ST by the thermistor 2 is 270 ° C. or lower in step 11. After this process is repeated for X1 seconds, the routine further proceeds to step 13, where it is determined whether or not the detected temperature ST is within the range of Y1 ° C. to 270 ° C. Further, when 120 seconds elapse from the ignition operation in step 14, monitoring is started in step 15 as to whether or not the detected temperature ST is in the range of Y1 ° C. to 250 ° C.
The reason why the temperature for 120 seconds after ignition is 270 ° C or lower is that the thermistor temperature rises due to residual heat when combustion is stopped. Therefore, in the case of reignition, the upper limit temperature is set at the initial stage of ignition so that the upper limit temperature is detected by residual heat and combustion is not stopped. This is to provide a 20 ° C. margin for the temperature.
[0021]
In such determination processing, if the detected temperature ST by the thermistor 2 is within the upper and lower temperature ranges, the combustion controller 7a determines that the temperature is normal and continues combustion, and if the temperature is outside the set temperature range, the temperature is determined to be abnormal. In step 16, the combustion is stopped.
X1 and Y1 are preferably set such that X1 = 30 seconds and Y1 = −3 ° C.
Therefore, since the set lower limit temperature is not monitored for 30 seconds after the ignition operation, the frozen food does not stop burning even if it is placed on a heating cooker, and the temperature of the frozen food rises due to heating after 30 seconds. Since it has reached −3 ° C. or higher, malfunction due to frozen food will not occur.
[0022]
Next, a second embodiment will be described based on FIG. 6 and FIG.
Note that the monitoring of the set upper limit temperature is the same as that of the first embodiment, and therefore, the description of the set upper limit temperature in the first embodiment is omitted from the description of the second embodiment and subsequent embodiments. Further, the set upper limit temperature on the flowchart is simply displayed as HT ° C. or lower, and the range display of the set upper limit temperature is omitted in the diagram showing the temperature range.
When the ignition operation is performed, first, in step 21, the combustion controller 7a monitors whether or not the detected temperature ST is in the range of the set lower limit temperature Y2 ° C. or more and the set upper limit temperature HT ° C. or less. When a time of X1 seconds elapses from the ignition operation in step 22, the detected temperature ST is changed from Y2 to Y1 ° C. to monitor whether the detected temperature ST is within the temperature range or not.
[0023]
In such a determination process, if the detected temperature ST of the thermistor 2 is within the upper and lower temperature ranges, it is determined to be normal and combustion is continued. To stop burning.
The second embodiment is different from the first embodiment in that the lower limit temperature is not monitored until X1 seconds have elapsed since the ignition operation in the first embodiment, whereas in the second embodiment, the Y2 from the initial ignition stage is not monitored. It is to monitor above ℃.
In other words, in the first embodiment, the disconnection failure monitoring is started after a certain time immediately after the ignition, whereas in the second embodiment, the combustion does not stop at a low temperature due to the frozen food immediately after the ignition. In other words, the judgment level of the disconnection failure is determined first when the resistance value is completely disconnected, and then the frozen food is heated and the temperature rises after a certain period of time, so the determination of the disconnection failure Switch to disconnection failure judgment when the level has a certain resistance value due to water drops or the like.
[0024]
The above X1, Y1, and Y2 are preferably set such that X1 = 30 seconds, Y1 = −3 ° C., and Y2 = −30 ° C.
Therefore, the set lower limit temperature is set to −30 ° C. and set to a level that does not cause malfunction due to frozen food, and after 30 seconds from the ignition operation, the set lower limit temperature can be set to −3 ° C. and set to a higher temperature. Since the set lower limit temperature can be set along with the temperature rise due to heating of frozen frozen food, disconnection failure of the temperature detection unit can be monitored without malfunction due to frozen food.
[0025]
Next, a third embodiment will be described with reference to FIG.
The third embodiment differs from the second embodiment in that monitoring at Y2 ° C. or higher is continued from X1 seconds after the ignition operation until combustion is stopped, and monitoring reliability is increased by double monitoring. is there.
In this case, it is possible to perform monitoring in parallel by incorporating each voltage comparison circuit having a different monitoring level instead of monitoring by a microcomputer. Therefore, even if one of the circuits breaks down, it is secured by the other circuit, which increases the monitoring reliability.
[0026]
In such a determination process, if the detected temperature ST of the thermistor 2 is within the above upper and lower temperature ranges, it is determined to be normal and combustion is continued, and if it is outside the predetermined temperature range, it is determined to be abnormal and combustion is stopped. .
In the figure, X1, Y1, and Y2 are preferably set such that X1 = 30 seconds, Y1 = −3 ° C., and Y2 = −30 ° C.
[0027]
Next, a fourth embodiment will be described based on FIG. 8 and FIG.
When the ignition operation is performed, first, in step 31, the combustion controller 7a monitors whether or not the detected temperature ST is in the range of the set lower limit temperature Y3 ° C. or more and the set upper limit temperature HT ° C. or less. When a time of X2 seconds elapses from the ignition operation in step 32, it is determined in step 33 whether or not the detected temperature ST is higher than Y1 ° C.
At this time, if the detected temperature ST exceeds Y1 ° C. due to reignition or the like, steps 34 and 35 are skipped to step 36, and it is monitored whether or not it is within the range of Y1 ° C. or more and HT ° C. or less. If the detected temperature ST is high immediately after ignition, it is assumed that it is due to reignition, and the intention is to change to high temperature monitoring without monitoring low temperature, and to quickly detect abnormalities in the temperature detection unit. Will have.
If the detected temperature ST is lower than Y1 ° C. in step 33 after X2 seconds have elapsed from the ignition operation, monitoring is started in step 34 as to whether or not the detected temperature ST is in the range of Y2 ° C. or higher and HT ° C. or lower. Further, when X1 seconds have elapsed from the ignition operation, in step 36, monitoring is started as to whether or not the detected temperature ST is in the range of Y1 ° C. or higher and HT ° C. or lower.
[0028]
In such determination processing, if the detected temperature ST of the thermistor 2 is within the above upper and lower temperature ranges, it is determined to be normal and combustion is continued, and if it is outside the predetermined temperature range, it is determined to be abnormal and in step 37 Stop burning.
The fourth embodiment is different from the third embodiment in that monitoring is performed by increasing the monitoring level from the ignition operation to X1 seconds in multiple stages. Further, if the detected temperature immediately after ignition reaches a high temperature from the beginning due to residual heat due to reignition or the like, the difference is that temperature monitoring at Y1 ° C. or higher is started immediately.
The above settings are preferably set such that X1 = 30 seconds, X2 = 15 seconds, Y1 = 0 ° C., Y2 = −5 ° C., and Y3 = −30 ° C.
Therefore, since the set lower limit temperature is switched and monitored according to the elapsed time after ignition, the set lower limit temperature can be set along with the temperature rise due to heating of frozen frozen food, that is, the judgment level of disconnection failure is changed. It is possible to monitor the disconnection failure of the temperature detection unit without malfunction due to frozen food.
[0029]
Next, a fifth embodiment will be described based on FIG. 9 and FIG.
When the ignition operation is performed, first, in step 41, the combustion controller 7a monitors whether or not the detected temperature ST is in the range of the set lower limit temperature Y3 ° C. or more and the set upper limit temperature HT ° C. or less. Subsequently, in step 42, whether or not the detected temperature ST is in the range of Y (Xt) ° C. or higher and HT ° C. or lower is monitored for X1 seconds. Here, Y (Xt) ° C. is not a constant value, but is calculated as a monitoring level proportional to the elapsed time from the ignition operation, and changes its value. That is, Y2 ° C. is a monitoring level Y (Xt) ° C. at an arbitrary elapsed time Xt seconds from the ignition operation to X1 seconds.
Thus, when X1 seconds have elapsed from the ignition operation, in step 44, monitoring is started as to whether or not the detected temperature ST is in the range of Y1 ° C. or higher and HT ° C. or lower.
[0030]
In such a determination process, if the detected temperature ST of the thermistor 2 is within the upper and lower temperature ranges, it is determined to be normal and combustion is continued, and if it is outside the predetermined temperature range, it is determined to be abnormal and in step 45 Stop burning.
The fifth embodiment is different from the fourth embodiment in that the monitoring level for X1 second from the ignition operation is further increased steplessly, and monitoring is performed at a monitoring level proportional to the elapsed time. .
Therefore, the setting lower limit temperature can be set according to the temperature rise due to the heating of frozen food, so the judgment level of disconnection failure is changed and the resistance value is changed from infinite complete disconnection to water resistance etc. Will be monitored. Therefore, it is possible to detect the disconnection failure of the temperature detection unit earlier than immediately after the ignition and to stop the combustion.
[0031]
Next, a sixth embodiment will be described based on FIG. 10 and FIG. When the ignition operation is performed, first, in step 51, the combustion controller 7a monitors whether or not the detected temperature ST is in the range of the set lower limit temperature Y3 ° C. or more and the set upper limit temperature HT ° C. or less. Further, after X3 seconds have elapsed from the ignition operation, in step 53, monitoring is started as to whether or not the detected temperature ST is in the range of Y (Xt) ° C. or higher and HT ° C. or lower. Here, Y (Xt) ° C. is not a constant value, but is changed as a monitoring level proportional to the elapsed time from X3 seconds to X1 seconds. That is, Y (Xt) ° C. is a monitoring level at an arbitrary elapsed time Xt seconds between X3 seconds and X1 seconds from the ignition operation.
Thus, when X1 seconds have elapsed since the ignition operation, in step 55, monitoring is started as to whether or not the detected temperature ST is in the range of Y1 ° C. or higher and HT ° C. or lower.
[0032]
In such determination processing, if the detected temperature ST of the thermistor 2 is within the above upper and lower temperature ranges, it is determined to be normal and combustion is continued, and if it is outside the predetermined temperature range, it is determined to be abnormal and in step 56 Stop burning.
The sixth embodiment is different from the fifth embodiment in that the monitoring level for X3 seconds from the ignition operation is a constant monitoring level of Y3 ° C.
Therefore, the set lower limit temperature immediately after ignition can be set to a level that does not cause malfunction due to frozen foods, and the set lower limit temperature Y (Xt) ° C. is higher from Y1 ° C. after X3 seconds have elapsed since the ignition operation. The temperature can be set, the set lower limit temperature can be set along with the temperature rise caused by heating the frozen frozen food, and the disconnection failure of the temperature detection unit can be monitored without malfunction due to the frozen food.
[0033]
Next, a seventh embodiment will be described based on FIG. 11 and FIG.
When the ignition operation is performed, first, in step 61, the combustion controller 7a monitors whether or not the detected temperature ST is in the range of the set lower limit temperature Y2 ° C. or more and the set upper limit temperature HT ° C. or less. In step 63 after X1 seconds have elapsed since the ignition operation, it is monitored whether the detected temperature gradient θ (Xt) is equal to or higher than the set level θ1. The temperature gradient θ (Xt) is calculated from the elapsed time and the detected temperature ST at that time based on the detected temperature ST at the initial stage of ignition. Alternatively, the calculation method may be calculated as the temperature gradient θ (Xt) from the values before and after the detected temperature ST for each unit time.
Thus, when X1 seconds have elapsed since the ignition operation, the routine proceeds to step 65 where monitoring of whether or not the detected temperature ST is in the range of Y1 ° C. or higher and HT ° C. or lower is started.
[0034]
In such a determination process, if the detected temperature ST of the thermistor 2 is within the upper and lower temperature ranges and the temperature gradient, it is determined to be normal and combustion is continued, and if it is outside the allowable temperature range, it is determined to be abnormal. At 66, the combustion is stopped.
As described above, the reason for determining the abnormality based on the gradient of the detected temperature ST in the early stage of ignition is as follows.
That is, when the frozen food is heated, the detected temperature ST rises with a temperature gradient. On the other hand, in the case of a disconnection failure, no temperature rise is detected and there is no temperature gradient. Therefore, it is possible to monitor whether there is a disconnection failure based on the difference. Moreover, immediately after ignition, it is irrelevant to the low temperature level caused by the frozen food, and the disconnection failure can be determined without malfunction due to the low temperature caused by the frozen food.
The seventh embodiment is different from the sixth embodiment in that it is monitored whether or not it is equal to or higher than a set lower limit temperature level in the sixth embodiment, whereas in the seventh embodiment, a set temperature gradient is monitored. It is the point which is monitoring whether it is above.
[0035]
Next, an eighth embodiment will be described with reference to FIGS.
When the ignition operation is performed, first, in step 71, the combustion controller 7a monitors whether or not the detected temperature ST is in the range of the set lower limit temperature Y2 ° C. or more and the set upper limit temperature HT ° C. or less. Further, when X2 seconds have elapsed from the ignition operation, in step 74, it is monitored whether or not the detected temperature gradient θ (Xt) is equal to or higher than the set temperature gradient θ1.
Thus, when X1 seconds have elapsed since the ignition operation, the routine proceeds to step 76 where monitoring is started as to whether or not the detected temperature ST is in the range of Y1 ° C. or more and the set upper limit temperature HT ° C. or less.
[0036]
In such determination processing, if the detected temperature ST of the thermistor 2 is within the upper and lower temperature ranges and the temperature gradient, it is determined to be normal and combustion is continued. Stop burning.
The eighth embodiment differs from the seventh embodiment in that the seventh embodiment monitors whether the temperature gradient is equal to or higher than the set temperature gradient immediately after the ignition operation, whereas the eighth embodiment is different from the seventh embodiment. First, monitoring whether or not the temperature is equal to or higher than the set temperature level is started, and monitoring whether or not the temperature is equal to or higher than a predetermined temperature gradient after a predetermined time has elapsed is started.
Therefore, when the amount of frozen food is large compared to the amount of heat generated by the combustion of cooking utensils, even when the amount of heat at the beginning of ignition is consumed for thawing and it is difficult to increase the temperature immediately after ignition, there is no malfunction caused by frozen food. It is possible to monitor the presence or absence of an abnormality in the temperature detection unit.
[0037]
Next, a ninth embodiment will be described with reference to FIGS.
When the ignition operation is performed, first, in step 81, the combustion controller 7b monitors whether or not the detected temperature ST is in the range of the set lower limit temperature Y2 ° C. or more and the set upper limit temperature HT ° C. or less. Subsequently, in step 82, it is monitored whether or not the detected temperature ST is Y1 ° C. or lower. If it is Y1 ° C. or lower, in step 83 it is monitored whether or not the detected temperature ST is Y1 ° C. or lower continues for ΔX seconds or longer.
[0038]
If YES is determined in step 81 or step 83 in the process of repeating such determination processing, it is determined as abnormal and combustion is stopped in step 84.
The ninth embodiment is different from the first to eighth embodiments in that the eighth embodiment monitors whether the temperature is over the set temperature range or over the temperature gradient, and the temperature is outside the set range. When the level or temperature gradient is detected even once, it stops, whereas in the ninth embodiment, even if a temperature outside the set temperature range is detected with respect to Y1 ° C., it does not stop if it recovers within the set time. .
Therefore, even if the frozen food is placed in the middle of combustion heating and the detected temperature ST temporarily falls below the set temperature, the combustion will not stop if it recovers within a certain time. A disconnection failure can be determined.
In this embodiment, it is determined whether or not the setting lower limit temperature or lower continues for the set time or longer. However, the present embodiment is not limited to the setting lower limit or lower, and it may be monitored whether or not the set temperature gradient or lower continues for the set time or longer. .
[0039]
Although the embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and it is needless to say that the present invention can be implemented in various modes without departing from the gist of the present invention.
For example, the heating cooker may be provided with a temperature adjustment function for maintaining the heating temperature of the food within a predetermined temperature range by automatically adjusting the heating power.
Further, it is also possible to adopt a middle level of the number of monitoring stages from the three-stage monitoring of the set lower limit temperature in the fourth embodiment to the no-stage in the fifth embodiment to obtain several monitoring levels. .
[0040]
Moreover, the schematic block diagram of the heating cooker as one embodiment shown in FIG. 1 is given as an example of controlling the opening and closing of the main electromagnetic valve 5 and the original electromagnetic valve 6 provided in the gas passage by the combustion controller 7a or 7b. However, in the case of manually opening the magnet safety valve and detecting the set upper limit temperature, a heating cooker that is controlled to be closed by the combustion controller 7a or 7b may be used.
In addition, as the third embodiment is different from the second embodiment, the monitoring before the transition is not canceled after the transition of the monitoring level in each embodiment, and the transition is performed even after the transition of the monitoring level. The previous monitoring may be performed in parallel.
Further, the ninth embodiment is combined with the first to eighth embodiments, and even if a temperature or temperature gradient outside the predetermined range is detected, the ninth embodiment does not stop if it recovers within the set time, and is not affected by a temporary phenomenon. It can also be monitoring.
[0041]
【The invention's effect】
As described above in detail, according to the heating cooker of the present invention, even if frozen frozen food is placed on the heating cooker, no malfunction that is determined as a disconnection failure occurs. Therefore, it is possible to provide a heating cooker that does not cause inconvenience in terms of use in which the frozen food must be thawed by leaving it for a while, and can be safely stopped even in the event of a failure of the temperature detection unit.
Also, for a certain period of time immediately after ignition, if the set upper limit temperature for preventing overheating is set to a value that is higher by a predetermined temperature, even if re-ignition is performed in a state where the temperature detector has increased in temperature due to residual heat after combustion stops, Does not stop burning.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a heating cooker as one embodiment.
FIG. 2 is a graph showing a relationship between detected temperature and resistance, which are thermistor characteristics.
FIG. 3 is a graph showing a relationship between a temperature range and time according to a conventional embodiment.
FIG. 4 is a graph showing a relationship between a temperature range and time according to a conventional embodiment.
FIG. 5 is a graph showing a relationship between a temperature range and time according to the first embodiment of the present invention.
FIG. 6 is a graph showing a relationship between a temperature range and time according to the second embodiment of the present invention.
FIG. 7 is a graph showing a relationship between a temperature range and time according to a third embodiment of the present invention.
FIG. 8 is a graph showing a relationship between a temperature range and time according to a fourth embodiment of the present invention.
FIG. 9 is a graph showing a relationship between a temperature range and time according to a fifth embodiment of the present invention.
FIG. 10 is a graph showing a relationship between a temperature range and time according to the sixth embodiment of the present invention.
FIG. 11 is a graph showing a relationship between a temperature range and time according to a seventh embodiment of the present invention.
FIG. 12 is a graph showing a relationship between a temperature range and time according to an eighth embodiment of the present invention.
FIG. 13 is a graph showing a relationship between a temperature range and time according to the ninth embodiment of the present invention.
FIG. 14 is a flowchart according to the first embodiment of the present invention.
FIG. 15 is a flowchart according to a second embodiment of the present invention.
FIG. 16 is a flowchart according to a fourth embodiment of the present invention.
FIG. 17 is a flowchart according to a fifth embodiment of the present invention.
FIG. 18 is a flowchart according to a sixth embodiment of the present invention.
FIG. 19 is a flowchart according to a seventh embodiment of the present invention.
FIG. 20 is a flowchart according to an eighth embodiment of the present invention.
FIG. 21 is a flowchart according to a ninth embodiment of the present invention.
FIG. 22 is a schematic configuration diagram of a heating cooker as a conventional embodiment.
[Explanation of symbols]
1 Cooking pan
2 Thermistor
4 Burner
7 Combustion controller

Claims (5)

When the cooking pan is placed, it comes into contact with the bottom of the pan and includes a temperature detection unit that detects the heating temperature of the food based on the electrical resistance value.
The temperature detected by the temperature detection unit is within an allowable temperature range that is equal to or lower than a set upper limit temperature set for preventing overheating and equal to or higher than a set lower limit temperature set for detecting a disconnection failure of the temperature detection unit. In a cooking device that stops combustion when the detected temperature is out of the allowable temperature range,
For a certain period of time immediately after ignition, there is provided disconnection detection canceling means that does not stop combustion even if the detected temperature is less than the set lower limit temperature, and when the frozen food is heated, the detected temperature after the lapse of the certain period of time is set as described above. A cooking device characterized in that the temperature reaches the lower limit temperature or more. When the cooking pan is placed, it comes into contact with the bottom of the pan and includes a temperature detection unit that detects the heating temperature of the food based on the electrical resistance value.
The temperature detected by the temperature detection unit is within an allowable temperature range that is equal to or lower than a set upper limit temperature set for preventing overheating and equal to or higher than a set lower limit temperature set for detecting a disconnection failure of the temperature detection unit. In a cooking device that stops combustion when the detected temperature is out of the allowable temperature range,
A lower limit temperature switching means for setting the set lower limit temperature immediately after ignition to a level lower than the detection temperature of the frozen food, and then switching to a temperature higher than the level;
A heater comprising: upper limit temperature switching means for setting the set upper limit temperature for preventing heating to a value higher by a predetermined temperature for a predetermined time after ignition. When the cooking pan is placed, it comes into contact with the bottom of the pan and includes a temperature detection unit that detects the heating temperature of the food based on the electrical resistance value.
The temperature detected by the temperature detection unit is within an allowable temperature range that is equal to or lower than a set upper limit temperature set for preventing overheating and equal to or higher than a set lower limit temperature set for detecting a disconnection failure of the temperature detection unit. In a cooking device that stops combustion when the detected temperature is out of the allowable temperature range,
For a certain period of time after ignition, the heating temperature gradient by the temperature detector is calculated without using the set lower limit temperature for detecting the disconnection failure, and a comparison is made as to whether or not the heating temperature gradient is greater than the set temperature gradient. If the temperature is equal to or lower than the set temperature gradient, the temperature detector is equipped with a temperature gradient monitoring means that determines that the temperature detection unit is disconnected and stops combustion. When the frozen food is heated, the temperature rises with a temperature gradient greater than the set temperature gradient for the predetermined time. A cooking device characterized by that. When the cooking pan is placed, it comes into contact with the bottom of the pan and includes a temperature detection unit that detects the heating temperature of the food based on the electrical resistance value.
The temperature detected by the temperature detection unit is within an allowable temperature range that is equal to or lower than a set upper limit temperature set for preventing overheating and equal to or higher than a set lower limit temperature set for detecting a disconnection failure of the temperature detection unit. In a cooking device that stops combustion when the detected temperature is out of the allowable temperature range,
It is monitored whether or not the temperature below the set lower limit temperature has continued for a certain period of time. If the temperature has continued for a certain period of time, it is determined that the temperature detection unit has failed and combustion is stopped. For example, it is provided with a continuation determination means that does not stop the combustion without determining the disconnection failure, and when the frozen food is heated, the continuation time during which the detected temperature is equal to or higher than the set lower limit temperature is less than the predetermined time. A heating cooker. 5. The cooking device according to claim 1, further comprising upper limit temperature switching means for setting the set upper limit temperature for preventing heating to a value higher by a predetermined temperature for a predetermined time after ignition.

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