JPH06213460A - Heating cooker - Google Patents

Abstract

(57) [Abstract] [Purpose] To shorten the time required to heat the sensor element to the characteristic stable temperature when the power is turned on so that the sensor element does not become high temperature even if it receives heat from the heating chamber. The zener voltages of the first to third zener diodes 42 to 44 connected to the base of the first transistor 40 are set to high, medium and low in the same order. When the ambient temperature of the sensor elements 14, 15 detected by the temperature sensor 12 is low, the second and third transistors 45, 46
Is turned off, and when a certain temperature is exceeded, the second transistor 4
5 is turned on, and when the temperature becomes high, the third transistor 46
Turn on. As a result, the voltage applied to the heater 16 is high,
Since it changes to middle and low, the sensor elements 14 and 15 can be heated to the characteristic stable temperature in a short time, and even if the sensor elements 14 and 15 receive heat from the heating chamber during oven cooking, the detection elements 14 and 15 do not become so high in temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating cooker equipped with a gas sensor for detecting gas such as water vapor or alcohol generated from an object to be cooked.

[0002]

2. Description of the Related Art A heating cooker, for example, a microwave oven, is equipped with a gas sensor for detecting gas such as steam or alcohol generated from an object to be cooked, and cooking is controlled based on the output of the gas sensor. Has been converted.

A gas sensor used in this type of microwave oven is provided with a sensor element showing a resistance value according to the gas concentration and a heater for heating the sensor element, and the gas attached to the sensor element is heated by the heater. It is made to diverge so that stable detection characteristics can always be obtained.

[0004]

By the way, in the microwave oven, when the power plug is connected to the outlet of the commercial power source, the heater of the gas sensor is energized to cause the sensor element to have a constant temperature necessary to diffuse the adhering gas. (Characteristic stable temperature; for example, about 50 ° C.), and thereafter, the heater is always energized to keep the sensor element heated to that temperature. As a result, the gas sensor shifts from an unstable state in the temperature rise process accompanying the start of energization of the heater to a stable state by maintaining a constant temperature, and in a standby state where stable detection characteristics can be exhibited no matter what time cooking starts. Becomes

However, the output (heat generation amount) of the heater is not so large because it is sufficient if the sensor element can be maintained at a constant temperature in the standby state. For this reason, when the power is turned on with the power plug connected to a commercial power outlet, the temperature of the sensor element rises slowly, and the unstable period until the sensor element is heated to a constant temperature becomes long. It was

On the other hand, FIG. 12 shows the rate of resistance change of the sensor element when the temperature of the atmosphere is changed without changing the gas concentration of the atmosphere of the gas sensor. As can be seen from the figure, when the temperature of the sensor element rises, the resistance value decreases even if there is no change in the gas concentration, and the same state is exhibited as if the gas concentration had changed.

Therefore, for example, in a microwave oven with an oven function, when the temperature of the sensor element rises due to the influence of the high temperature atmosphere in the heating chamber during cooking in the oven, the output (voltage) of the gas sensor The correlation between the gas concentration and the gas concentration changes, and normal cooking control cannot be performed.

The present invention has been made in view of the above circumstances, and an object thereof is to shorten the time required for the sensor element to reach the characteristic stable temperature when the power is turned on, and to be thermally influenced by the heating chamber, for example. However, it is an object of the present invention to provide a heating cooker capable of preventing the sensor element from becoming so high in temperature.

[0009]

The cooking device according to the present invention comprises:
A sensor equipped with a gas sensor having a sensor element for detecting a gas such as water vapor or alcohol generated from an object to be cooked, and a heater for heating the sensor element, detecting the ambient temperature of the sensor element, and detecting the ambient temperature. The heat generation amount of the heater is controlled based on the temperature.

In this case, a temperature sensor for detecting the ambient temperature of the sensor element may be provided, and control means for controlling the amount of heat generated by the heater based on the temperature detected by the temperature sensor may be provided. Further, a resistor whose resistance value changes according to temperature is used as a temperature sensor for detecting the ambient temperature of the sensor element, and this temperature sensor is used with respect to the heater when the voltage applied to the heater is The connection may be changed so as to change according to the change in resistance value.

[0011]

When the power is turned on, the ambient temperature of the gas sensor is low, so the amount of heat generated by the heater increases, and the temperature of the sensor element rises in a short time to reach a stable state. Further, when the atmospheric temperature of the gas sensor rises, for example, when cooking in an oven, the amount of heat generated by the heater decreases, and the temperature rise of the sensor element is reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 1 to 4 by applying it to a microwave oven with an oven function. FIG. 4 shows a schematic configuration of a microwave oven. In FIG. 4, a waveguide 2 is connected to the heating chamber 1 and is radiated from a magnetron 4 provided in a machine chamber 3 during cooking in a microwave oven. Microwaves are supplied into the heating chamber 1 through the waveguide 2. During the operation of the magnetron 4, the cooling fan 5 provided in the machine room 3 is driven, and the wind blown from the cooling fan 5 cools the magnetron 4, and a part of the wind is in the heating chamber 1. It is taken in and is discharged from the exhaust duct 6 to the outside.

Further, an oven heater 7 and a circulation fan 8 are provided on the rear side of the heating chamber 1, and during heating in the oven, the air heated by the heater 7 is circulated by the circulation fan 8 on the back side of the heating chamber 1. It is circulated through the group of holes 1a. A turntable 10 rotated by a motor 9 is arranged at the bottom of the heating chamber 1.

A gas sensor 11 for detecting the gas generated from the food, such as water vapor and alcohol, is arranged in the exhaust duct 6, and the ambient temperature of the gas sensor 11 is provided in the vicinity of the gas sensor 11. A temperature sensor 12 including a thermistor for detecting is provided.

As shown in FIG. 3, the gas sensor 11 has a sensor element 14 for detecting water vapor and a sensor element 15 for detecting alcohol on a base 13 made of ceramics.
And a heater 16 for heating both of these sensor elements 14 and 15 to diffuse gas attached to the sensor elements 14 and 15. In this embodiment, both sensor elements 14 and 15 are integrally formed into a cylindrical shape, and a heater 16 is provided inside thereof.
Then, the sensor elements 14 and 15 and the heater 16
Is covered by a protective net 17. The sensor elements 14 and 15 have resistance values that change according to the water vapor concentration and the alcohol concentration, respectively.

FIG. 1 shows the configuration of a control circuit relating to the gas sensor 11. In FIG. 1, the control circuit 18 includes a microcomputer 19 as a control means. Then, each sensor element 1 of the gas sensor 11
One of terminals 4 and 15 is connected to the positive power supply terminal + Vcc,
The other terminal has a plurality of resistors 20 to 2 connected in parallel.
Output ports O1 to O6, O7 to O12 of the microcomputer 19 via 5, 26 to 31, respectively.
It is connected to the. The resistors 20 to 25 group, the resistor 2
The groups 6 to 31 constitute a voltage dividing circuit together with the sensor elements 14 and 15, and the common connection point is the port I1 of the microcomputer 19 and the port I1 of the microcomputer 19 via the filter circuit composed of the resistors 32 and 33 and the capacitors 34 and 35. It is connected to I2.

At the start of cooking, the microcomputer 19 actually drops the ports O1 to O6 and O7 to O12 to a low level to actually form a voltage dividing circuit from the resistors 20 to 25 and the resistors 26 to 31. The resistance to be selected is selected so that the optimum combined resistance value can be obtained in relation to the sensor elements 14 and 15. That is, the sensor element 1
The characteristics of Nos. 4 and 15 are slightly different for each product, and the characteristics also change depending on the environment in which they are used. Therefore, this is corrected by selectively setting an optimum combined resistance value.

Further, one terminal of the temperature sensor 12 is connected to the power supply terminal + Vcc, and the other terminal is grounded via the resistor 36. The resistor 36 constitutes a voltage dividing circuit together with the temperature sensor 12, and its common connection point is the resistor 37.
It is connected to the input port I3 of the microcomputer 19 through a filter circuit composed of a capacitor 38 and a capacitor 38.

The input ports I1 to I3 are A / D
It serves as an input port of the converter, and the voltage signal input to each port is converted into a digital value and processed by the microcomputer 19.

On the other hand, the heater 16 of the gas sensor 11 is supplied with electric power via the applied voltage control circuit 39. In the applied voltage control circuit 39, the first transistor 4
The collector of 0 is connected to the positive power supply terminal + V1, and the emitter is grounded via the heater 16. The base of the first transistor 40 is connected to the positive power supply terminal + V1 via the resistor 41 and the cathodes of the first to third Zener diodes 42 to 44. The anode of the first Zener diode 42 is grounded, and the second and third Zener diodes 43 are
The anodes of and 44 are connected to the collectors of the second and third transistors 45 and 46, respectively.
Then, the second and third transistors 45 and 46
Is grounded and the base is connected to the output ports O13 and O14 of the microcomputer 19.

Here, the Zener voltages of the first to third Zener diodes 42 to 44 are highest in the first Zener diode 42, lowest in the third Zener diode 44, and second Zener diode 43. It is set in the middle of them. Then, the emitter voltage of the first transistor 40, and hence the applied voltage of the heater 16, is set to high, medium, or low depending on which of the first to third Zener diodes 42 to 44 functions.
Controlled in stages.

That is, the emitter voltage of the first transistor 40 is a voltage obtained by subtracting the voltage between the base and the emitter from the base voltage. When the second and third transistors 45 and 46 are both off, the first Zener diode 42 is in a functional state, so that the base voltage of the first transistor 40 is the first Zener diode 42. The zener voltage is 42, and the voltage applied to the heater 16 at this time is a high voltage indicated by VH in FIG. When the second transistor 45 turns on,
Since the second Zener diode 43 becomes functional, the base voltage of the first transistor 40 becomes the Zener voltage of the second Zener diode 43 which is one step lower,
The applied voltage of the heater 16 at this time is VM in FIG.
When the second and third transistors 45 and 46 are both turned on, the voltage becomes a medium standard voltage shown by
Since the third Zener diode 44 is in a functioning state, the base voltage of the first transistor 40 becomes the Zener voltage of the third Zener diode 44, and the voltage applied to the heater 16 at this time is a low voltage indicated by VL. Becomes

Next, the operation of the above configuration will be described. Figure 2 now
It is assumed that the power plug (not shown) of the microwave oven is connected to the outlet of the commercial power source at the time indicated by t1. Then,
The power is turned on and the microcomputer 1
9 is initialized and starts to operate according to a predetermined program, reads the temperature detected by the temperature sensor 12 at regular intervals, and reads the detected temperature from the first reference temperature T1, shown in FIG.
The second reference temperature T2 (T1 <T2) is compared. Further, when the power is turned on, the first transistor 40 is turned on and the heater 16 of the gas sensor 11 is turned on.

Since the temperature of the heater 16 of the gas sensor 11 is still low when the power is turned on, the temperature detected by the temperature sensor 12 is the first reference temperature T1 as shown in FIG. 2 (a).
Lower than that of the microcomputer 19
Causes the ports O13 and O14 to go low, turning off the second and third transistors 45 and 46.
Therefore, the second and third Zener diodes 43 and 44 are deactivated and the first transistor 4
The base voltage of 0 is held at the Zener voltage of the first Zener diode 42. As a result, the heater 16 is
As shown in FIG. 2D, the high voltage TM is applied, and the heater 16 receives a large amount of electric power to generate a large amount of heat.

Thus, when the power is turned on, the heater 16
Since the amount of heat generated is large, the sensor elements 14 and 15 are heated strongly to a characteristic stable temperature at which the adhering gas can be released in a short time, and the sensor elements 14 and 15 are in a standby state.

On the other hand, the heat generated by the heater 16 causes the ambient temperature of the gas sensor 11 to gradually rise. When the temperature detected by the temperature sensor 12 reaches the first reference temperature T1 shown in FIG. 2 (a) (this time is shown by t2), the microcomputer 19 switches the output port O13 to the high level. Then, the second transistor 45 is turned on as shown in FIG. Then, the second Zener diode 43 operates in place of the first Zener diode 42, so that the base voltage of the first transistor 40 becomes the Zener voltage of the second Zener diode 43. As a result, the medium standard voltage VM is applied to the heater 16 as shown in (d) of FIG.
15 is kept at a constant temperature, and the sensor elements 14 and 15 are kept in a stable state.

Now, suppose that after the sensor elements 14 and 15 are heated to the characteristic stable temperature and are in the standby state, the oven cooking is started at the time indicated by t3 in FIG. Then,
Since the inside of the heating chamber 1 is heated to a high temperature by the heater 7 for the oven and the circulating fan 8, the thermal influence thereof reaches the sensor elements 14 and 15. When this happens, the ambient temperature of the gas sensor 11 naturally rises, and when the temperature detected by the temperature sensor 12 reaches the second reference temperature T2 (this point is shown by t4 in FIG. 2), the microcomputer 19
Switches the output port O14 to the high level state and turns on the third transistor 46. Then, instead of the second Zener diode 43, the third Zener diode 44
Becomes functional, the base voltage of the first transistor 40 becomes the Zener voltage of the third Zener diode 44. As a result, the low voltage VL is applied to the heater 16 as shown in FIG. 2 (d), the amount of heat generated by the heater 16 decreases, and even if there is a thermal influence from the heating chamber 1. The temperature of the sensor elements 14 and 15 should not be so high.

As described above, according to this embodiment, the heat generation amount of the heater 16 is controlled according to the ambient temperature of the gas sensor 11, so that the heat generation amount of the heater 16 becomes large when the power source is turned on at a low ambient temperature. Sensor element 14, 15
The time required to reach a stable state can be shortened. Also,
When the gas sensor 11 becomes thermally affected in the heating chamber 1 during cooking in the oven, the calorific value of the heater 16 decreases and the temperature of the sensor elements 14 and 15 is prevented from increasing so much. There is no possibility that the characteristics of the above will change, and the cooking control by the microcomputer 19 will be performed normally.

Incidentally, FIG. 2 (e) shows a change in the detection signal (voltage) of one sensor element 14 input to the input port I1 of the microcomputer 19, and the solid line in this embodiment shows The broken line shows the case where the voltage applied to the heater 16 is set to the standard voltage VM which is always medium after the power is turned on. In the case of the oven cooking shown in the figure, an object to be cooked is not placed in the heating chamber 1, but the inside of the heating chamber 1 is simply heated to a high temperature by the heater 7 for the oven and the circulation fan 8 (idling). is there.

As is apparent from FIG. 2 (e), when the standard voltage VM is constantly applied to the heater 16 (corresponding to the prior art), the temperature rise of the sensor elements 14 and 15 when the power is turned on is slow. Therefore, the time required for the detection characteristics to stabilize becomes longer, and when the oven cooking is started, it is affected by the heat from the heating chamber 1. It is understood that the characteristics of the sensor elements 14 and 15 change due to the change of On the other hand, in this embodiment, when the power is turned on, the time required for the sensor elements 14 and 15 to reach a stable state is short,
Further, it can be seen that the detection signal is stable and the characteristics of the sensor elements 14 and 15 do not change even in the case of baking.

FIG. 5 shows a second embodiment of the present invention. The difference from the first embodiment is that the temperature sensor 12 is provided in the gas sensor 11. Specifically, the temperature sensor 12 is mounted on the base 13, and the sensor elements 14, 1
5 and the heater 16 are covered with a protective net 17. In this way, the temperature sensor 12 is replaced by the gas sensor 1
If it is provided in No. 1, the temperature of the portion closer to the sensor elements 14 and 15 can be detected.

FIG. 6 shows a third embodiment of the present invention. The difference from the first embodiment is the heat generation control structure of the heater of the gas sensor. That is, as shown in the figure, the heater 47 of the gas sensor 11 is composed of three resistance heating elements 48 to 50. One terminal of these resistance heating elements 48 to 50 is connected to the emitter of the transistor 52 of the constant voltage circuit 51, and the other terminal is connected to the collectors of the transistors 53 to 55, respectively. The emitters of the transistors 53 to 55 are grounded, and the bases are connected to the output ports O15 to O17 of the microcomputer 19.

On the other hand, in the constant voltage circuit 51, the collector of the transistor 52 is connected to the positive power supply terminal + V1, the base is connected to the cathode of the Zener diode 56 and the positive power supply terminal + V1 via the resistor 57. ing. The anode of the Zener diode 56 is grounded. Therefore, when the power is turned on, a constant voltage obtained by subtracting the voltage between the base and emitter of the transistor 52 from the Zener voltage of the Zener diode 56 is applied to each of the resistance heating elements 48 to 50.

The temperature detected by the temperature sensor 12 is the first
When the temperature is lower than the reference temperature T1 of (1) when the power is turned on, the microcomputer 19 sets one output port O15 to the high level to turn on the transistor 53, and the temperature detected by the temperature sensor 12 exceeds the first reference temperature T1. Then, in addition to the output port O15, the port O16 is set to the high level to turn on the transistor 54, and when the temperature detected by the temperature sensor 12 exceeds the second reference temperature (during oven cooking, etc.), the output port O17 is also set to the high level. Then, all the three transistors 53 to 55 are turned on.

Therefore, depending on the temperature detected by the temperature sensor 12, only one resistance heating element 48 is energized (large heat generation amount), or two resistance heating elements 48 and 49 are energized (medium heat generation amount). Alternatively, a state in which all of the three resistance heating elements 48 to 50 are energized (small heat generation amount) can be obtained, so that the same effect as that of the first embodiment described above can be obtained.

FIG. 7 shows a fourth embodiment of the present invention. The difference from the first embodiment is the specific construction of the gas sensor. That is, a ceramic substrate 60 is mounted on the base 59 of the gas sensor 58. This board 6
On the upper surface of 0, sensor elements 61 for detecting water vapor and sensor elements 62 for detecting alcohol are provided on the left and right sides thereof, and a heater 63 is provided between these sensor elements 61, 62.

Here, the sensor elements 61 and 62 are
Is, for example, a sintered powder obtained by adding a different additive to zinc oxide as a base material on the upper surface of the substrate 60 by a known printing means and firing it. The heater 63 uses carbon powder as the printing means. It is adhered onto the substrate 60 by the above method and is covered with a peeling preventive agent 64 and baked. With this configuration, both sensor elements 61 and 62 can be efficiently heated by the heater 63, and the gas sensor 58 can be made thin as a whole. A temperature sensor may be mounted on the board 60.

When the sensor elements 61, 62 and the heater 63 are provided on the substrate 59 by the printing means, the heater 6 is provided on the back surface of the substrate 65 as shown in FIG. 8 showing the fifth embodiment of the present invention.
3 is provided and the sensor elements 61 and 62 are provided on the upper surface of the substrate 65, the substrate 65 can be made small in the width direction, so that the gas sensor can be made even smaller.

9 and 10 show a sixth embodiment of the present invention. The same parts as those in FIG. 1 showing the first embodiment are designated by the same reference numerals and only different parts will be described. In this embodiment, the resistor 66 shown in FIG. 9 is used as the temperature sensor, and the resistor 66 is used for the sensor elements 14 and 15.
4 is provided at the same position as the temperature sensor 12 shown in FIG.

One end of the resistor 66 is connected to the gas sensor 1
The first heater 16 is grounded in series, and the other end is connected to the constant voltage circuit 67. The constant voltage circuit 67 is the low voltage circuit 5 in the third embodiment shown in FIG.
6 has the same configuration as that of FIG.
The same reference numeral is given to omit detailed description. The resistor 66 has a positive temperature characteristic that the resistance value increases as the temperature rises, and is made of nickel, for example.

The temperature coefficient of the resistor 66 is 6900 × 1.
At about 0 ^-6, for example, a temperature coefficient of resistance of the nichrome heater made of 16 is about 20 × ^{10 -6.} Due to the large difference in temperature coefficient from the heater 16, the resistor 66
The resistance value of is substantially smaller than the resistance value of the heater 16 at room temperature, and is substantially the same as the resistance value of the heater 16 when the gas sensor 11 is heated by the heater 16 and reaches a characteristic stable temperature. The resistance value of the heater 16 is significantly larger than the resistance value of the heater 16 when the temperature is high due to the influence.

In this embodiment thus constructed, it is assumed that the power plug of the microwave oven is plugged into the outlet at the time t1 in FIG. 10 and the power is turned on. At this time, the resistance value of the resistor 66 is smaller than the resistance value of the heater 16 as shown in FIG.
As shown in (c), the voltage applied to the heater 16 is high, so that the heater 16 is supplied with a large amount of electric power to generate a large amount of heat and the temperature of the gas sensor 11 rapidly increases as shown in FIG. The temperature rises to the characteristic stable temperature.

When the gas sensor 11 is heated to the characteristic stable temperature (this time is indicated by t2 in FIG. 10), the resistor 66
Since the resistance value of is substantially equal to the resistance value of the heater 16, the voltage applied to the heater 16 is medium, the amount of heat generated by the heater 16 is medium, and the gas sensor 11 is maintained at the characteristic stable temperature.

It is assumed that the oven cooking is started at the time indicated by t3 in FIG. Then, the ambient temperature of the gas sensor 11 rises, so that the resistance value of the resistor 66 changes to the heater 16
Significantly higher than the resistance value of. Then, the applied voltage of the heater 16 becomes low, the heat generation amount of the heater 16 becomes small, and the temperature of the gas sensor 11 is prevented from rising so much.

FIG. 10 (d) shows changes in the detection signal of the sensor element 14 input to the microcomputer 19, as in FIG. 2 (e). In the case of the present embodiment, the solid line shows the heater 16 and the broken line shows it. The applied voltage of is set to a standard voltage which is always medium after the power is turned on, that is, a voltage corresponding to the applied voltage from time t2 to time t3 among the applied voltages of the heater 16 shown in FIG. Show. As is apparent from FIG. 10, even with the configuration of the present embodiment, the time required for the sensor elements 14 and 15 to reach a stable characteristic state when the power is turned on is short, and oven cooking or the like is performed. In this case, the temperature of the sensor elements 14 and 15 can be prevented from rising so much.

FIG. 11 shows a seventh embodiment of the present invention. The difference from the sixth embodiment is that the resistor 68 used as a temperature sensor is a low antibody having a negative temperature characteristic. It is in. In this embodiment, the resistor 68
Is connected in parallel to the heater 16, one end of a parallel circuit of the heater 16 and the resistor 68 is connected to the constant voltage circuit 67 via the resistor 69, and the other end is grounded.

In such a configuration, as the ambient temperature of the gas sensor 11 rises, the combined resistance value of the parallel circuit of the heater 16 and the resistor 68 increases, so the voltage applied to the parallel circuit (heater). 16 applied voltage) becomes gradually lower as the ambient temperature of the gas sensor 11 rises. For this reason, the heater 16 receives a high applied voltage when the power is turned on and is in a high heat generation state, and when the gas sensor 11 rises to a characteristic stable temperature, it receives a medium applied voltage and is in a medium heat generation state, and when oven cooking or the like is performed. The applied voltage is lowered and the heat generation is low. Therefore, even if it is configured as in the present embodiment, it is possible to obtain the same effect as that of the sixth embodiment.

In the sixth and seventh embodiments, the resistors 66 and 68 may be provided in the gas sensor 11 as in the temperature sensor 12 shown in FIG. 5, and the gas sensors shown in FIGS. You may use the thing of the structure shown in FIG.

Besides, the present invention is not limited to the embodiments described above and shown in the drawings. For example, a gas sensor may be provided with only one sensor element to detect one kind of gas, and There are various conceivable methods for controlling the heat generation amount of the heater of the gas sensor, such as duty ratio control and PWM control. Furthermore, the present invention is not limited to gas sensors for microwave ovens, but can be widely applied to gas sensors for general heating cookers, and various modifications can be made without departing from the scope of the invention.

[0050]

As described above, according to the present invention, the ambient temperature of the sensor element is detected, and the heat generation amount of the heater for heating the sensor element is controlled based on the detected temperature. When the heater is turned on, the amount of heat generated by the heater can be increased to shorten the time required for the gas sensor to reach the characteristic stable temperature, and when cooking in an oven, the amount of heat generated by the heater can be reduced to reduce the sensor element. This has an excellent effect that stable detection characteristics can be exhibited without increasing the temperature so much.

[Brief description of drawings]

FIG. 1 is a control circuit configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a signal generation state of each unit after power is turned on.

FIG. 3 is a perspective view of the gas sensor shown partially broken away.

FIG. 4 is a vertical sectional front view showing a schematic configuration of a microwave oven.

FIG. 5 is a view corresponding to FIG. 3 showing a second embodiment of the present invention.

FIG. 6 is a circuit configuration diagram of a main part showing a third embodiment of the present invention.

FIG. 7 is a perspective view of a gas sensor showing a fourth embodiment of the present invention.

FIG. 8 is a perspective view of a main part of a gas sensor showing a fifth embodiment of the present invention.

FIG. 9 is a circuit configuration diagram of essential parts showing a sixth embodiment of the present invention.

FIG. 10 is a view corresponding to FIG.

FIG. 11 is a circuit configuration diagram of a main part showing a seventh embodiment of the present invention.

FIG. 12 is a characteristic diagram for explaining a defect of a conventional gas sensor.

[Explanation of symbols]

1 is a heating chamber, 11 is a gas sensor, 12 is a temperature sensor, 1
Reference numerals 4 and 15 are sensor elements, 16 is a heater, 18 is a control circuit, 19 is a microcomputer (control means), 39 is an applied voltage control circuit, 47 is a heater, 48 to 50 are resistance heating elements, 51 is a constant voltage circuit, 58 is a gas sensor, 6
0 is a substrate, 61 and 62 are sensor elements, 63 is a heater, 6
Reference numeral 5 is a substrate, and 66 and 68 are low antibodies (temperature sensors).

Claims (6)

[Claims] 1. A gas sensor having a sensor element for detecting a gas such as water vapor or alcohol generated from an object to be cooked, and a heater for heating the sensor element. A heating cooker characterized by being configured to detect and control the amount of heat generated by the heater based on the detected temperature. 2. A gas sensor having a sensor element for detecting a gas such as water vapor or alcohol generated from an object to be cooked and a heater for heating the sensor element, wherein the ambient temperature of the sensor element is A heating cooker comprising a temperature sensor for detecting and a control means for controlling the amount of heat generated by the heater based on the temperature detected by the temperature sensor. 3. The heater according to claim 2, wherein the heater comprises a plurality of resistance heating elements, and the control means controls the heating value of the heater by selecting a resistance heating element to be energized. Heating cooker. 4. A gas sensor having a sensor element for detecting a gas such as water vapor or alcohol generated from an object to be cooked and a heater for heating the sensor element, wherein a resistance value changes depending on temperature. The changing resistor is used as a temperature sensor for detecting the ambient temperature of the sensor element, and this temperature sensor is used for the heater so that the voltage applied to the heater changes according to the change in the resistance value of the temperature sensor. A cooker characterized by being connected to. 5. The cooking device according to claim 2, wherein the temperature sensor is provided on the gas sensor. 6. The gas sensor is characterized in that a plurality of sensor elements for detecting different gases and a heater for heating the sensor elements are provided on one substrate by a printing means. The cooking device according to any one of claims 1 to 5.