JP2835238B2 - Electric cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric cooker using a lamp heater as a heat source, and more particularly to an electric cooker whose output is controlled so that the ambient temperature of the lamp heater does not become abnormally high.

[0002]

2. Description of the Related Art In an electric cooker of this type, a halogen lamp is usually used as a lamp heater, and cooking is performed by heat generated by the halogen lamp. Specifically, the heating unit is configured by covering the periphery and the bottom of the plurality of halogen lamp groups with a heat insulator, and further, the upper surface of the heat insulator is covered with a light-transmitting top plate such as heat-resistant glass. Then, a pot serving as a cooking vessel is placed on the top plate, and the object placed in the pot is cooked by heat generated by a halogen lamp.

[0003] In such an electric cooker, heat generated from the halogen lamp is transmitted to the pot by radiation or conduction through a top plate. Since the heat capacity of the top plate is relatively large, the temperature of the top plate does not easily rise at the start of heating, heat conduction via the top plate is expected to be thin, and the rise of the temperature of the pot is deteriorated. Thus, conventionally, a halogen lamp having a high output of, for example, 2 KW is used so that the temperature of the top plate rises quickly.

On the other hand, in this electric cooker, in order to enhance the thermal efficiency, a heat insulating body and a top plate are brought into close contact with each other to form a closed space inside the heating unit. Therefore, when the halogen lamp is continuously energized, the ambient temperature of the halogen lamp, that is, the air temperature in the heating unit gradually increases,
It exceeds the heat resistance limit temperature (about 600 ° C.) of the top plate and the heat resistance limit temperature (about 850 ° C.) of the quartz glass tube constituting the bulb of the halogen lamp.

Therefore, in a conventional electric cooker, a thermostat is provided as a temperature detecting means for detecting the temperature in the heating unit, and the output of the halogen lamp is controlled in accordance with the on / off of the thermostat.

More specifically, as shown in FIG. 12, the thermostat turns off when the ambient temperature of the halogen lamp rises to the upper limit set temperature, and turns on when the ambient temperature drops to the lower limit set temperature. Then, the on / off signal of the thermostat is input to a microcomputer as a control device, and the microcomputer controls the output of the halogen lamp to 2 KW when the thermostat is on, and to half the 1 KW when the thermostat is off. .

According to this output control configuration, FIG.
As shown by the solid line, the temperature in the heating unit does not greatly deviate from between the upper limit set temperature and the lower limit set temperature, so that the top plate and the bulb of the halogen lamp do not rise to their heat-resistant limit temperatures. It is done as follows.

[0008] When the ambient temperature of the halogen lamp is higher than the upper limit set temperature, the halogen lamp is not cut off and is kept in a low output state of 1 kW because of the time required for cooking when the cutoff occurs. This is to prevent this since the length becomes longer. In addition, the top plate, which had been brightly illuminated by the halogen lamp, suddenly goes dark, giving the user an uneasy feeling that a malfunction may have occurred.

[0009]

According to the above-described output control structure, in the case of ordinary heating cooking such as cooking using a metal pot, the metal pot has good heat conductivity. Therefore, when the output of the halogen lamp is reduced to 1 KW, the amount of heat radiation from the heating unit (mainly, the amount of heat transferred to the pot side) exceeds the amount of heat generated by the halogen lamp.
As a result, the temperature inside the heating unit decreases to the lower limit set temperature due to the reduction in the output of the halogen lamp.

However, for example, when a pebble is put in a clay pot to bake potatoes and chestnuts, the clay pot has low thermal conductivity, and the clay pot has a large heat capacity (including pebbles) and has good heat insulation. In addition, unlike cooking cooking, there is no heat radiation due to evaporation of water, so if heating progresses to a certain extent, even if the output of the halogen lamp is reduced to 1 KW, a halogen lamp, contrary to a metal pot with good heat conductivity, is used. Of the heating unit exceeds the amount of heat radiation from the heating unit. As a result, the temperature in the heating unit does not decrease to the lower limit setting temperature, and conversely, as shown by the two-dot chain line in FIG. Becomes ascending beyond. Eventually, the temperature inside the heating unit becomes abnormally high, and the top plate and the bulb of the halogen lamp become damaged above the heat-resistant limit temperature.

[0011] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an apparatus in which the atmosphere temperature of a lamp heater is abnormally high even when cooking is performed using a cooking container having good heat conductivity and heat retention. An object of the present invention is to provide an electric cooker that is unlikely to become an electric cooker.

[0012]

According to a first aspect of the present invention, there is provided an electric cooker in which a lamp heater is used as a heat source, the upper part of the electric heater is covered with a top plate, and the electric heater is placed on the top plate. A heater for heating a cooking vessel such as a hot pot, provided with a temperature detecting means for detecting an ambient temperature of the lamp heater, and the temperature detecting means detects the upper limit set temperature of the lamp heater with the start of energization of the lamp heater. Control to switch from the high output state to the low output state and to switch from the low output state to the high output state when detecting the lower limit set temperature and to gradually decrease the output value in the high output state every time the upper set temperature is detected. Means is provided, and the control means switches the lamp heater to a low output state by the upper limit set temperature detection of the temperature detection means, and thereafter, within a predetermined time, When degree detecting means does not detect the lower limit set temperature, and is characterized in that it is configured to lower to a lower constant low output value an output of the lamp heater.

[0013] In the electric cooker according to the second aspect, after the control means reduces the output of the lamp heater to a constant low output value,
When the temperature detecting means detects the lower limit set temperature within a predetermined time, the lamp heater is returned to the high output state and controlled in the same manner as the control accompanying the start of energization, and the temperature detector does not detect the lower limit set temperature within the predetermined time. Sometimes, the lamp heater is configured to be turned off.

[0014]

According to the present invention, when the lamp heater is energized in a high output state by the start of heating, the ambient temperature of the lamp heater gradually increases. Then, when the temperature detecting means detects the upper limit set temperature, the output of the lamp heater is reduced, and when the ambient temperature of the lamp heater falls to the lower limit set temperature, the lamp heater is again set to the high output state. Then, every time the temperature detecting means detects the upper limit set temperature, the output of the halogen lamp is gradually reduced. This is the output (calorific value) of the lamp heater
Is automatically adjusted in a direction that balances the amount of heat taken by the cooking container (such as a pot containing the food).

On the other hand, when the lamp heater is switched to the low output state, the amount of heat generated by the lamp heater is normally smaller than the amount of heat transferred to the cooking vessel side, so that the ambient temperature of the lamp heater is set to the lower limit. Drops to temperature. However, in a cooking vessel such as an earthen pot with low heat conductivity and good heat retention, the heat generated by the lamp heater exceeds the amount of heat transferred to the cooking vessel, so the ambient temperature of the lamp heater drops to the lower limit setting temperature. Instead, it gradually rises. Then, since the temperature detecting means does not detect the lower limit set temperature within the predetermined time, the control means reduces the output of the lamp heater to a constant low output value. Therefore,
The ambient temperature of the lamp heater becomes lower.

After that, when the temperature detecting means detects the lower limit set temperature within a predetermined time, the control means controls the lamp heater in the same manner as the control accompanying the start of energization, so that there is no possibility that the lamp heater will be left at a low output. .

If the temperature detecting means does not detect the lower limit set temperature within a predetermined time after the output of the lamp heater has been reduced to a low output value, the lamp heater is cut off.
There is no possibility that the lamp heater will be left for a long time while the ambient temperature is high.

[0018]

1 to 9 show a first embodiment of the present invention.
It will be described based on.

First, as shown in FIG. 5, the outer frame 1 of the electric cooker is formed in a flat rectangular box shape, for example, 3
A heating unit 2 is provided at the location. As shown in FIGS. 6 and 7, these heating units 2 sandwich a plurality of, for example, four, halogen lamps 3 as lamp heaters between upper and lower heat insulators 4 and 5 each having an oval shape. The heat insulator 5 is fixed to the inner bottom surface of the outer frame 1 via the saucer 6. These four halogen lamps 3
Is set to, for example, 2 KW.

The upper surface of the upper heat insulator 4 of each heating unit 2 is covered with a translucent top plate 7 such as a single piece of heat-resistant glass. The inside of the heating unit 2 is hermetically sealed. The temperature in the sealed heating unit 2, that is, the ambient temperature of the halogen lamp 3, is detected by a thermostat 8 as a temperature detecting means.

The thermostat 8 is turned on and off by a heat-sensitive portion 9 in which a metal rod (not shown) which expands and contracts due to a temperature change is disposed in a metal outer tube, and the metal rod of the heat-sensitive portion 9 expands and contracts. And a switch unit 10.
The heat sensing unit 9 is disposed in the heating unit 2 and the switch unit 1
0 is provided outside the heating unit 2. The off set temperature (upper limit set temperature) of the thermostat 8 is 7
The on-set temperature (lower limit set temperature) is set to be 700C. Therefore, thermostat 8
Is an ON period until the temperature inside the heating unit 2 rises to 750 ° C., and an OFF period until the temperature inside the heating unit 2 falls to 700 ° C. after the ON operation.

An operation panel 11 is provided on the outer frame 1 so as to be aligned with the top plate 7. As shown in FIG. 8, the operation panel 11 has "ON" and "OFF" switches 12 and 1 for starting and stopping heating.
3. "Input up" and "input down" switches 14 and 15 for adjusting the output of the halogen lamp 3, that is, the amount of heat generation (substantially the same as the input amount), and the magnitude of the output of the halogen lamp 3 Are provided in plurality. In this case, enter
The output of the halogen lamp 3, which can be adjusted by both the "p" and "input down" switches 14 and 15, is set in a range from its maximum output of 2 KW to 1.6 KW.

Although the above-mentioned various switches 12 to 15 and the light emitting diodes 16 are provided in a one-to-one relationship with each heating unit 2, only one corresponding to one heating unit is shown in the drawing for convenience.

As shown in FIG. 9 (only one heating unit is shown), the four halogen lamps 3 of the heating unit 2 are connected in parallel to an AC power supply 17 as shown in FIG. The halogen lamp group 3 is controlled by a microcomputer 18 as control means. The microcomputer 18 receives power from a constant voltage circuit 19 connected to an AC power supply 17. Further, between the constant voltage circuit 19 and the microcomputer 18, there is provided an initialization circuit 20 for detecting that the voltage of the constant voltage circuit 19 has become equal to or higher than a predetermined voltage when the power is turned on and initializing the microcomputer 18. .

The microcomputer 18 controls various electric components included in the electric cooker, receives signals from the thermostat 8 and various switches 12 to 15, and receives the signals from the light emitting diodes 16 in accordance with the input signals. The halogen lamps 3 are controlled by controlling the triac 21 connected in series with the halogen lamps 3 via a drive circuit 22 while turning off the power.

In this case, the microcomputer 18
When the “ON” switch 12 is operated, the “OFF” switch 1
The halogen lamp 3 is turned on until the operation of the halogen lamp 3 is performed. During this energization, the output of the halogen lamp 3 is controlled to a high output during the on-period of the thermostat 8, and to a low output during the off-period, for example, to 出力 of the high output. The output of the halogen lamp 3 is controlled by the triac 21
This is performed by phase control via.

The output of the halogen lamp 3 during the ON period of the thermostat 8 (output in a high output state)
Is set by both the "input up" and "input down" switches 14 and 15, and the set output is switched by a signal from the thermostat 8 after the start of energization. .

That is, the microcomputer 18 turns on the halogen lamp 3 each time the thermostat 8 detects the upper limit set temperature and turns off after the halogen lamp 3 is energized.
Of the maximum output (2 KW) of 5
% (0.1 KW). In this case, the output of the halogen lamp 3 is gradually reduced in a range of a constant output value, for example, 1.6 KW or more. When the output decreases to 1.6 KW, the thermostat 8 is thereafter turned off and remains on during the ON period. Programmed to remain. Accordingly, in a state where the output of the halogen lamp 3 is controlled by switching between high and low (high / low switching control), the output value in the low output state is 0.8.
KW is the lower limit.

Further, the microcomputer 18 has a timer function for performing a time counting operation by a timer program or the like. When the thermostat 8 detects the upper limit set temperature and turns off when the thermostat 8 detects the upper limit set temperature, if the thermostat 8 detects the lower limit set temperature and does not turn on within a predetermined time T (for example, 15 minutes), the halogen lamp 3 is configured to be reduced to a constant low output value lower than 0.8 KW, which is the lower limit output value of the low output state in the high / low switching control, for example, 0.5 KW.

Next, the operation of the above configuration will be described with reference to the time charts of FIGS.

The time charts of FIGS. 1 and 3 show a case where pebbles 24 are put in a clay pot 23 having low heat conductivity as shown in FIG. This shows a case in which stew cooking is performed using a metal pot 26 having good properties.

First, referring to FIG. 3 showing the case of a metal pan 26 having good heat conductivity, in order to start heating cooking,
Operate the “input” switch 12 and the “input up” switch 14
Alternatively, the user operates the “input down” switch 15 to set the output of the halogen lamp 3 in the high output state.

Now, it is assumed that the output of the halogen lamp 3 in the high output state is set to its maximum output of 2 KW. Then, first, the halogen lamp 3 generates heat with a high output of 2 KW,
The heat is transmitted to the pot 26 placed on the top plate 7 by radiation or by conduction through the top plate 7, and the pot 26 is heated, while the temperature in the heating unit 2 also rises rapidly. When the temperature in the heating unit 2 becomes equal to or higher than the upper limit set temperature, the thermostat 8 is turned off.
Reduces the output of the halogen lamp 3 by half and switches to a low output state of 1 KW (at time t1 in FIG. 3).

When the temperature inside the heating unit 2 drops to the lower limit set temperature, the thermostat 8 is turned on, so that the halogen lamp 3 generates heat at an output of 1.9 KW, which is 0.1 KW lower than the previous high output (FIG. 3). At time t2). Then, the temperature in the heating unit 2 rises again to the upper limit set temperature, and the thermostat 8 is turned off again (t in FIG. 3).
3 times), the output of halogen lamp 3 is half of 0.95K
It is reduced to W. As a result, the temperature in the heating unit 2 decreases, and when the thermostat 8 is turned on again, the halogen lamp 3 is energized so as to generate heat at an output of 1.8 KW, which is 0.1 KW lower than the output at the time of the previous high output ( FIG.
Each time the thermostat 8 is turned off, the output at the time of high output of the halogen lamp 3 becomes 1.6K.
It is gradually reduced by 0.1 KW until it becomes W.

By the way, the rise in the temperature inside the heating unit 3 means that the output (heat generation) of the halogen lamp 3 is the amount of heat radiated from the heating unit 3 (mainly the amount of heat absorbed by the pan 26).
It is because it exceeds. And the halogen lamp 3
Is gradually reduced each time the thermostat 8 is turned off, which means that the calorific value of the halogen lamp 3 approaches the absorbed calorific value of the pot 26.

For this reason, assuming that when the output of the halogen lamp 3 in the high output state is reduced to, for example, 1.8 KW, the calorific value and the absorbed heat amount of the pot 26 are balanced, FIG. Thereafter, as indicated by the dashed line, the temperature in the heating unit 2 is maintained at a temperature between the upper and lower set temperatures. Therefore, the thermostat 8 is not turned off, and the halogen lamp 3 is kept at 1.8K until the end of heating.
The output state of W is maintained.

Further, as shown by the solid line in FIG. 3, even when the output of the halogen lamp 3 in the high output state was reduced to 1.6 KW, the calorific value of the halogen lamp 3 still exceeded the amount of heat absorbed by the pot 26. In that case, the thermostat 8 is turned on and off thereafter. However, since the amount of heat generated by the halogen lamp 3 approaches the amount of heat absorbed by the pot 26, the on / off cycle of the halogen lamp 3 becomes longer.

On the other hand, when the thermostat 8 detects the upper limit set temperature and turns off, the microcomputer 18 starts the timing operation in addition to switching the halogen lamp 3 to the low output state as described above. However, in the pan 26 having good heat conductivity, when the halogen lamp 3 is set to the low output state, the amount of heat radiation from the heating unit 2 (mainly the pan 26)
Of the halogen lamp 3).

For this reason, the temperature in the heating unit 2 gradually decreases, and before the microcomputer 18 finishes counting the predetermined time T, the temperature falls to the lower limit set temperature. Therefore, the microcomputer 18 supplies the predetermined time T
The ON signal is input from the thermostat 8 before elapse, and as a result, the microcomputer 18 maintains the high / low switching control state in which the output of the halogen lamp 3 is switched by high / low control.

As described above, when cooking is performed using a pot having a good thermal conductivity, when the halogen lamp 3 is set to a low output, the amount of heat generated by the halogen lamp 3 is smaller than the amount of heat radiation from the heating unit 2. Therefore, the temperature inside the heating unit 2 always drops to the lower limit set temperature, and the halogen lamp 3
Does not occur even though the power is reduced to a low level.

By controlling the output of the halogen lamp 3 as described above, the calorific value of the halogen lamp 3 is set close to the absorbed heat of the pot 26, and the temperature in the heating unit 2 is set to the heat resistance limit of the halogen lamp 3 and the top plate 7. Heat cooking is performed while preventing the temperature from becoming abnormally high such as the temperature. Then, after heating the pot 26 for a desired time, the "OFF" switch 13 is operated to end the cooking.

Next, the case of the earthen pot 23 having low heat conductivity will be described with reference to FIG. 1. Assume that the output of the halogen lamp 3 is set to 2 KW and heating is started in the same manner as described above. Then, while the pot 23 on the top plate 7 is heated, the temperature in the heating unit 2 also rises rapidly, and when the temperature in the heating unit 2 reaches the upper limit set temperature,
Since the thermostat 8 is turned off, the halogen lamp 3 is switched to the low output state of 1 KW in the same manner as described above (at time t1 in FIG. 1).

When the temperature inside the heating unit 2 drops to the lower limit set temperature, the thermostat 8 is turned on, so that the halogen lamp 3 generates heat at an output of 1.9 KW, which is 0.1 KW lower than the previous high output (FIG. 1). At time t2), the halogen lamp 3 is switched between a high output state and a low output state in accordance with the on / off state of the thermostat 8, and the output of the halogen lamp 3 is increased by 0.1 KW each time the thermostat 8 is turned off. It is gradually reduced.

On the other hand, when the thermostat 8 detects the upper limit set temperature and turns off, the microcomputer 18 starts the timing operation in addition to switching the halogen lamp 3 to the low output state as described above. However, at the beginning of heating, if the output of the halogen lamp 3 is reduced,
As in the case of the pot 26 having good thermal conductivity, the amount of heat generated by the halogen lamp 3 is smaller than the amount of heat released from the heating unit 2, so that the inside of the heating unit 2 drops to the lower limit set temperature within a predetermined time T. I do. Accordingly, the microcomputer 18 maintains a high / low switching control state in which the output of the halogen lamp 3 is switched by high / low control.

However, when the heating of the earthen pot 23 proceeds, the heat conductivity of the earthen pot 23 is low, and the earthen pot 23 has a good heat retaining property and, unlike cooking of stew, does not lose heat due to evaporation of water. Even if the output of the halogen lamp 3 is in a low output state, the heat generation amount of the halogen lamp 3 exceeds the heat release amount of the heating unit 2.

After the amount of heat generated in the low output state of the halogen lamp 3 exceeds the amount of heat transferred from the heating unit 2 to the earthen pot 23, the thermostat 8 is turned off.
When the thermostat 8 is turned off and the output of the halogen lamp 3 is reduced by turning off the thermostat 8, the temperature in the heating unit 2 does not drop to the lower limit set temperature, and conversely rises. As a result, the thermostat 8 remains in the off state.

For this reason, the microcomputer 18
At time t5, when the halogen lamp 3 is switched to the low output state and the timekeeping operation is started, at time t5
After that, the microcomputer 18 does not receive the ON signal from the thermostat 8 for a predetermined time T.
Is terminated (at this point, t is shown in FIG. 1).
6).

Then, the microcomputer 18 reduces the output of the halogen lamp 3 to a constant low output value of 0.5 KW at the time point t6 when the counting of the predetermined time T ends. Due to the reduction in the output of the halogen lamp 3, the temperature inside the heating unit 2 gradually decreases thereafter. As a result, the temperature inside the heating unit 2 does not become abnormally high. There is no possibility that the valve will become higher than the heat resistant temperature.

Thereafter, when the temperature in the heating unit 2 drops to the lower limit set temperature, the thermostat 8 is turned on (this point is indicated by t7 in FIG. 1). Then, the microcomputer 18 returns the output of the halogen lamp 3 to the high output state at the beginning of energization (in this case, 2 KW), and thereafter, in accordance with the start of energization, the same control as the control, that is, the output of the halogen lamp 3 is turned on / off of the thermostat 8. The high / low switching control for switching the high / low is performed according to the control. If the thermostat 8 is not turned on within a predetermined time T after the halogen lamp 3 is switched to the low output state by turning off the thermostat 8, the microcomputer 18 changes the output of the halogen lamp 3 in the same manner as described above. It is repeated to lower to 0.5 KW.

As described above, according to the present embodiment, the output of the halogen lamp 3 is gradually reduced each time the thermostat 8 is turned off, so that the output of the halogen lamp 3 is automatically adjusted in a direction to balance the heat absorbed by the cooking vessel. Can be adjusted. Therefore, when cooking using the earthen pot 23, when the halogen lamp 3 is in a low output state, the heating unit 2
It is possible to prevent the occurrence of a situation in which the internal temperature does not decrease to the lower limit set temperature but rises as much as possible.

When the temperature inside the heating unit 2 rises even after the halogen lamp 3 is switched to the low output state, the output of the halogen lamp 3 is further reduced after a predetermined time T has elapsed. Output value (0.5
KW), it is possible to prevent the occurrence of a serious accident leading to damage to the bulb of the halogen lamp 3 and the top plate 7. In this case, the halogen lamp 3
And then the thermostat 8 is turned on again at t7
It is also conceivable that the halogen lamp 3 is re-energized at this point in time. However, in this case, the top plate 7 which has been brightly illuminated by the halogen lamp 3 becomes completely dark, so that the user is notified that cooking is completed. Misunderstanding,
There is a risk that the "off" switch 13 is left without being operated. Also, even if you do not make such a misconception,
There is a problem that the time until the end of cooking becomes longer,
In this embodiment, such a problem does not occur.

FIGS. 10 and 11 show a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that a predetermined time T1 (for example, several minutes) further elapses after the output of the halogen lamp 3 is reduced to a constant low output value of 0.5 KW. If the thermostat 8 does not turn on by then, the halogen lamp is cut off when the time T1 has elapsed.

That is, in FIG. 10, after the halogen lamp 3 is switched to the low output state, the thermostat 8 does not turn on until a predetermined time T has elapsed, and the output of the halogen lamp 3 is reduced to 0.5 kW at time t6. It shall have been done. Then, the microcomputer 18 starts counting the elapsed time from the time t6. And
As shown by the two-dot chain line in FIG. 1, when the thermostat 8 is turned on within the time T1 (this time is indicated by t8 in FIG. 10), at the time t9 when the time T1 has elapsed, the first embodiment is replaced with the first embodiment. Similarly, the output of the halogen lamp 3 is returned to the high output state at the beginning of energization (in this case, 2 kW), and thereafter, the high / low switching control state for switching the output of the halogen lamp 3 to high or low according to the on / off of the thermostat 8 is maintained. When the thermostat 8 is turned off, the halogen lamp 3 is turned off.
If the thermostat 8 is not turned on within the predetermined time T after the power supply is switched to the low output state, the microcomputer 18 repeatedly reduces the output of the halogen lamp 3 to 0.5 kW.

On the other hand, as shown by the solid line in FIG. 10, when the thermostat 8 is kept off without being turned on within the time T1 from the time t6, the microcomputer 18 sets the time T1 at that time. Elapsed time t
9, the halogen lamp 3 is turned off, and an abnormality notification lamp 27 provided on the operation panel 11 as shown in FIG.
Lights up. Then, the user operates the abnormality notification lamp 2
7 turns on and notices that the inside of the overheating unit 2 has been overheated. For example, the "input down" switch 15 is operated to lower the output of the halogen lamp 3, and the "on" switch 12 is operated again to restart the heating. I do.

As described above, according to this embodiment, even if the output of the halogen lamp 3 is reduced to a low output value, if the thermostat 8 is not turned on within the predetermined time T1, the halogen lamp 3 is cut off. Therefore, the temperature inside the heating unit 2 is not left as it is above the lower limit set temperature for a long time, and the protection of the halogen lamp 3 and the top plate 7 can be ensured. That is, even if the output of the halogen lamp 3 is reduced to a certain low output value (0.5 KW), the fact that the thermostat 8 does not turn on means that the temperature in the heating unit 2 is left for a long time at the lower limit set temperature or higher. Means that. Depending on the time, the bulb of the halogen lamp 3 and the top plate 7 are adversely affected. However, in this embodiment, the heating unit 2
There is no danger that the temperature inside will remain above the lower limit set temperature for a long time.

[0056]

As described above, according to the present invention, the following effects can be obtained.

In the electric cooker according to the first aspect, when the temperature detecting means does not detect the lower limit set temperature within a predetermined time after switching the lamp heater to the low output state, the output of the lamp heater is further reduced to a constant low level. With the configuration in which the output value is reduced, it is possible to prevent the ambient temperature of the lamp heater from being abnormally high even when heating and cooking is performed using a cooking container having good heat conductivity and heat retention.

In the electric cooking device according to the second aspect, after the output of the lamp heater is reduced to a constant low output value, when the temperature detecting means detects the lower limit set temperature within a predetermined time, the lamp heater is turned on. When the temperature detection means does not detect the lower limit set temperature within a predetermined time,
Since the lamp heater is configured to be turned off, the lamp heater will not be left at a low output, and if the temperature detecting means does not detect the lower limit set temperature within a predetermined time, the lamp heater will be turned off. Since the lamp heater is charged, there is no possibility that the lamp heater will be left for a long time while the ambient temperature is high, and the lamp heater and the top plate can be protected completely.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the output control form of a halogen lamp, a change in the ambient temperature of a halogen lamp, and a change in on / off of a thermostat when a clay pot is heated in the first embodiment of the present invention.

FIG. 2 is a partial longitudinal side view when heating a clay pot.

FIG. 3 is a diagram corresponding to FIG. 1 when a normal metal pan is heated.

FIG. 4 is a diagram corresponding to FIG. 2 when a normal metal pan is heated.

FIG. 5 is a perspective view schematically showing the entire electric cooker.

FIG. 6 is a vertical sectional front view of a heating unit.

FIG. 7 is a perspective view of a heating unit.

FIG. 8 is a plan view of a switch portion.

FIG. 9 is a block diagram of an electric circuit.

FIG. 10 is a view corresponding to FIG. 1, showing a second embodiment of the present invention;

FIG. 11 is a diagram corresponding to FIG. 8;

FIG. 12 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

2 is a heating unit, 3 is a halogen lamp (lamp heater), 7 is a top plate, 8 is a thermostat (temperature detecting means), 18 is a microcomputer (control means)
It is.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F24C 7/04 301

Claims (2)

(57) [Claims] 1. A temperature detecting means for detecting an ambient temperature of a lamp heater, wherein the lamp heater is used as a heat source, a portion above the cover is covered with a top plate, and a cooking vessel such as a pot placed on the top plate is heated. Switching the lamp heater from a high output state to a low output state when the temperature detecting means detects the upper limit set temperature and starting from a low output state to a high output state when detecting the lower limit set temperature with the start of energization of the lamp heater. And control means for controlling the output value in the high output state to be gradually reduced every time the upper limit set temperature is detected, and wherein the control means detects the upper limit set temperature of the temperature detecting means, thereby detecting the lamp heater. When the temperature detection means does not detect the lower limit set temperature within a predetermined time after switching to a low output state, the output of the lamp heater is further increased. An electric cooker configured to lower to a low constant low output value. 2. The control means reduces the output of the lamp heater to a constant low output value, and returns the lamp heater to a high output state and energizes when the temperature detection means detects a lower limit set temperature within a predetermined time. 2. The electric cooking apparatus according to claim 1, wherein the control is performed in the same manner as the control associated with the start, and when the temperature detecting means does not detect the lower limit set temperature within a predetermined time, the lamp heater is turned off. vessel.