JPH05280754A - Electric cooking device - Google Patents

Abstract

PURPOSE:To prevent an abnormal rise in the ambient temp. of a heater by a method wherein, when the prescribed minimum temp. of a lamp heater is not detected within a predetermined time after switching the lamp heater to a low output operation, its output is further lowered to a predetermined value. CONSTITUTION:When a lamp heater 3 is switched to a low output condition, its ambient temp. normally drops to a prescribed minimum temp. However, in the case of the cooking vessel, e.g. earthen pot, low in heat conductivity and good in heat insulation, since the quantity of heat produced by the lamp heater 3 exceeds that transferred to the cooking vessel, the ambient temp. of the lamp heater 3 does not drop to the prescribed minimum temp. but rises gradually. Since a temp. detecting means 8 does not detect the prescribed minimum temp. within a predetermined time, a control means 18 reduces the output of the lamp heater 3 to a predetermined low value. Therefore, the ambient temp. of the lamp heater 3 becomes low. This can prevent the ambient temp. of the lamp heater 3 from becoming abnormally high.

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 one for controlling the output of the lamp heater so that the ambient temperature does not become abnormally high.

[0002]

2. Description of the Related Art In this type of electric cooker, a halogen lamp is usually used as a lamp heater, and heat is cooked by the heat generated by the halogen lamp. Specifically, the periphery and bottom of a plurality of halogen lamp groups are covered with a heat insulator to form a heating unit, and the top surface of the heat insulator is covered with a translucent top plate such as heat-resistant glass. Then, a pan serving as a cooking container is placed on the top plate, and the food to be cooked in the pan is heated and cooked by the heat generated by the halogen lamp.

In such an electric cooker, the heat emitted from the halogen lamp is transferred to the pot by radiation or by conduction through the top plate. Since the heat capacity of this top plate is comparatively large, the temperature of the top plate does not rise easily at the start of heating, and the heat conduction through the top plate is expected to be thin, and the rise of the temperature of the pot deteriorates. Therefore, conventionally, a halogen lamp having a high output of, for example, 2 KW has been used so that the temperature of the top plate is quickly raised.

On the other hand, in this electric cooker, in order to improve the heat efficiency, the heat insulator and the 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 rises,
The heat-resistant limit temperature (about 600 ° C.) of the top plate and the heat-resistant limit temperature (about 850 ° C.) of the quartz glass tube constituting the bulb of the halogen lamp are exceeded.

Therefore, in the 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 according to the on / off state of the thermostat.

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 temperature falls to the lower limit set temperature. The on / off signal of the thermostat is input to a microcomputer, which is a control device, and the microcomputer controls the output of the halogen lamp to 2 KW when the thermostat is on and to 1 KW which is half when the thermostat is off. ..

According to this output control configuration, FIG.
As shown by the solid line, the temperature inside the heating unit does not deviate significantly from between the upper limit setting temperature and the lower limit setting temperature, so the bulbs of the top plate and halogen lamp do not rise to their heat-resistant limit temperature. Is done like this.

[0008] When the ambient temperature of the halogen lamp exceeds the upper limit set temperature, the halogen lamp is not cut off but kept in a low output state of 1 kW because the time required for cooking is cut off. This is to prevent this because it becomes long. In addition, the top plate, which had been brightly illuminated by the halogen lamp, suddenly went dark and made the user feel anxious that it might have broken down.

[0009]

According to the above-mentioned output control structure, the metal pot has good thermal conductivity in the case of normal cooking such as cooking using a metal pot. Therefore, when the output of the halogen lamp is reduced to 1 KW, the amount of heat released from the heating unit (mainly the amount of heat transferred to the pan side) exceeds the amount of heat generated by the halogen lamp.
As a result, the output of the halogen lamp is reduced, so that the temperature in the heating unit is lowered to the lower limit set temperature.

However, for example, when putting pebbles in a clay pot to bake potatoes, chestnuts, etc., the clay pot has low thermal conductivity, and the clay pot has a large heat capacity (including pebbles) and good heat retention. In addition, unlike cooking boiled food, there is no heat dissipation due to water evaporation, so even if the output of the halogen lamp is reduced to 1 kW when the heating progresses to a certain extent, contrary to a metal pot with good thermal conductivity, a halogen lamp The amount of heat generated in the heating unit exceeds the amount of heat dissipated from the heating unit, and as a result, the temperature inside the heating unit does not drop to the lower limit set temperature, and conversely, as indicated by the chain double-dashed line in Figure (a), Will rise 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.

The present invention has been made in view of the above circumstances. An object of the present invention is that the ambient temperature of the lamp heater is abnormally high even if the cooking is performed using a cooking container having good thermal conductivity and heat retention. It is to provide an electric cooker that is not likely to become.

[0012]

In order to solve the above problems, an electric cooker according to the present invention as set forth in claim 1 uses a lamp heater as a heat source, the upper part of which is covered with a top plate and placed on the top plate. For heating a cooking container such as a pot, temperature detecting means for detecting the ambient temperature of the lamp heater is provided, and the temperature detecting means detects the upper limit set temperature of the lamp heater when the lamp heater is energized. When the high output state is switched to the low output state and the lower limit set temperature is detected When the low output state is switched to the high output state and the output value in the high output state is gradually decreased each time the upper limit set temperature is detected Means is provided, and the control means switches the lamp heater to a low output state by detecting the upper limit set temperature of the temperature detecting means, and then 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.

In the electric cooker according to the second aspect, the control means reduces the output of the lamp heater to a constant low output value, and thereafter,
When the temperature detection means detects the lower limit set temperature within the predetermined time, the lamp heater is returned to the high output state and is controlled in the same manner as the control accompanying the start of energization, and the temperature detection means does not detect the lower limit set temperature within the predetermined time. It is sometimes characterized in that the lamp heater is configured to be cut off.

[0014]

According to the invention of the above means, when the lamp heater is energized in a high output state by the start of heating, the ambient temperature of the lamp heater gradually rises. 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 is lowered to the lower limit set temperature by this, the lamp heater becomes high output state again. Then, each time the temperature detecting means detects the upper limit set temperature, the output of the halogen lamp is gradually reduced. This is the output of the lamp heater (heat generation amount)
Is automatically adjusted in a direction that balances with the amount of heat lost to the cooking container (a pot containing the food to be cooked, etc.).

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 usually smaller than the amount of heat transferred to the cooking vessel, so the ambient temperature of the lamp heater is set to the lower limit. It drops to temperature. However, in a cooking container with low heat conductivity and good heat retention, such as a clay pot, the amount of heat generated by the lamp heater exceeds the amount of heat transferred to the cooking container, so the ambient temperature of the lamp heater drops to the lower limit setting temperature. Instead, it will gradually rise. 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 gradually decreases.

Then, after that, when the temperature detecting means detects the lower limit set temperature within the 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 of being 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 is reduced to a low output value, the lamp heater is cut off.
There is no risk of the lamp heater being left at high temperature for a long time.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.
It will be explained based on.

First, as shown in FIG. 5, the outer frame 1 of the electric cooker is formed in a flat rectangular box shape, and the inside thereof is, for example, 3 mm.
The heating unit 2 is arranged at the location. As shown in FIGS. 6 and 7, these heating units 2 sandwich a plurality of halogen lamps 3 as lamp heaters, for example, four halogen lamps 3 between upper and lower heat insulators 4 and 5, which have bottoms. The heat insulating body 5 is fixed to the inner bottom surface of the outer frame 1 via the saucer 6. In addition, these four halogen lamps 3
The total maximum output of 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 piece of heat-resistant glass. The inside of the heating unit 2 is sealed by being closely attached. The temperature inside 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 temperature change is arranged in an outer tube made of metal, and the metal rod of the heat sensitive portion 9 expands and contracts. It is composed of a switch unit 10 and
The heat sensitive section 9 is disposed in the heating unit 2 and the switch section 1
0 is arranged outside the heating unit 2. The off set temperature (upper limit set temperature) of the thermostat 8 is 7
The temperature is set to 50 ° C. and the ON set temperature (lower limit set temperature) is set to 700 ° C. Therefore, thermostat 8
Is an ON period until the temperature in the heating unit 2 rises to 750 ° C., and is an OFF period until the temperature in the heating unit 2 drops to 700 ° C. after the ON operation.

An operation panel 11 is provided on the outer frame 1 side by side with the top plate 7. On the operation panel 11, as shown in FIG. 8, respective switches 12 and 1 for "ON" and "OFF" 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 heat generation amount (substantially the same as the input amount) are provided, and the output of the halogen lamp 3 is large. Is provided with a plurality of light emitting diodes 16 for displaying. In this case, type "u
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 the range from its maximum output of 2 KW to 1.6 KW.

Although the various switches 12 to 15 and the light emitting diode 16 are provided in a one-to-one relationship with each heating unit 2, only the ones corresponding to one heating unit are shown in the drawings for the sake of convenience.

The electric circuit configuration of this electric cooker is as shown in FIG. 9 (only one heating unit is shown), and the four halogen lamps 3 of the heating unit 2 are connected in parallel to the AC power supply 17. The halogen lamp 3 group is controlled by the microcomputer 18 as a control means. The microcomputer 18 is adapted to receive power from a constant voltage circuit 19 connected to the AC power supply 17. An initialization circuit 20 is provided between the constant voltage circuit 19 and the microcomputer 18 to detect that the constant voltage circuit 19 has reached a predetermined voltage or higher when the power is turned on and initialize the microcomputer 18. ..

The microcomputer 18 controls various electric parts of the electric cooker, receives signals from the thermostat 8 and various switches 12 to 15, and receives the light emitting diode 16 in accordance with the input signals. The halogen lamp 3 group is controlled by turning off the power and controlling the triac 21 connected in series with the halogen lamp 3 group via the drive circuit 22.

In this case, the microcomputer 18 is
When the "ON" switch 12 is operated, the "OFF" switch 1
The halogen lamp 3 is energized until 3 is operated. The output of the halogen lamp 3 during the energization is controlled to be a high output during the ON period of the thermostat 8 and a low output during the OFF period, for example, an output of 1/2 of the high output. The output control of the halogen lamp 3 is performed by the triac 21.
Phase control via the.

The output of the halogen lamp 3 during the ON period of the thermostat 8 (the output in the high output state)
Is set by both the "input up" and "input down" switches 14 and 15, and the set output can be 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.
The output in the high output state of the
% (0.1 kW) is programmed to be gradually decreased. In this case, the output of the halogen lamp 3 is gradually reduced within a constant output value, for example, 1.6 KW or more, and when the output decreases to 1.6 KW, even if the thermostat 8 is turned off thereafter, 1.6 KW is maintained during the ON period. Is programmed to remain. Therefore, in the 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. Then, when the thermostat 8 detects the upper limit set temperature and turns off, the time counting operation is started, and thereafter, when 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 The output of No. 3 is configured to be lowered to a constant low output value lower than 0.8 KW which is the lower limit output value in 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 the case where the pebbles 24 are put in the clay pot 23 having a low heat conductivity to bake the potatoes 25 as shown in FIG. 2 and the heat conduction as shown in FIG. It shows the case of cooking a stew with a metal pan 26 having good properties.

First, referring to FIG. 3 showing the case of the metal pan 26 having good thermal conductivity, in order to start the heating cooking,
Operate the "ON" switch 12 to move the "Input up" switch 14
Alternatively, the "input down" switch 15 is operated to set the output of the halogen lamp 3 in the high output state.

It is now 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 conduction through the top plate 7 to heat the pot 26, while the temperature in the heating unit 2 also rises rapidly. When the temperature inside the heating unit 2 becomes equal to or higher than the upper limit set temperature, the thermostat 8 is turned off, and the microcomputer 18 receives the off signal.
Cuts the output of the halogen lamp 3 in half and switches to a low output state of 1 KW (time t1 in FIG. 3).

As a result, 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 a decrease of 0.1 KW from the previous high output (FIG. 3). (At time t2). Then, the temperature in the heating unit 2 again rises to the upper limit set temperature, and the thermostat 8 is turned off again (t in FIG. 3).
3), the output of halogen lamp 3 is half, 0.95K
Lowered to W. As a result, the temperature inside 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 ( Figure 3
Each time the thermostat 8 is turned off, such as t4), the output of the halogen lamp 3 at high output is 1.6K.
It is gradually reduced by 0.1 kW until it reaches W.

By the way, the rise in the temperature in the heating unit 3 means that the output of the halogen lamp 3 (heat generation amount) is the amount of heat released from the heating unit 3 (mainly the amount of heat absorbed by the pot 26).
Because it is above. And halogen lamp 3
The output in the high output state is gradually reduced each time the thermostat 8 is turned off, which means that the amount of heat generated by the halogen lamp 3 approaches the amount of heat absorbed by the pan 26.

Therefore, when the output of the halogen lamp 3 in a high output state is reduced to, for example, 1.8 KW, if the calorific value of the halogen lamp 3 and the absorbed calorific value of the pan 26 are in a balanced state, FIG. After that, as indicated by the dotted line, the temperature inside the heating unit 2 will be maintained between the upper and lower set temperatures. Therefore, the thermostat 8 does not turn off, and the halogen lamp 3 remains 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 dropped to 1.6 KW, the calorific value of the halogen lamp 3 still exceeded the absorbed calorific value of the pan 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 becomes longer.

On the other hand, when the thermostat 8 detects the upper limit set temperature and turns off, the microcomputer 18 switches the halogen lamp 3 to the low output state as described above, and starts the time counting operation. However, when the halogen lamp 3 is set to a low output state in the pot 26 having good thermal conductivity, the amount of heat released from the heating unit 2 (mainly the pot 26).
Absorbed heat amount) exceeds the heat value of the halogen lamp 3.

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

In the case of cooking using a normal pot having good thermal conductivity, when the halogen lamp 3 is made to have a low output, the calorific value of the halogen lamp 3 becomes larger than the heat dissipated from the heating unit 2. The temperature inside the heating unit 2 always drops to the lower limit set temperature, and the halogen lamp 3
However, the situation in which the temperature inside the heating unit 2 rises does not occur, even though the output is low.

By controlling the output of the halogen lamp 3 as described above, the heat generation amount of the halogen lamp 3 approaches the absorption heat amount of the pan 26, and the temperature inside the heating unit 2 heat-limits the halogen lamp 3 and the top plate 7. Cooking is performed while avoiding an abnormally high temperature such that the temperature becomes higher than or equal to the temperature. Then, after heating the pot 26 for a desired time, the "OFF" switch 13 is operated to complete the cooking.

Next, the case of the clay pot 23 having a low thermal conductivity will be described with reference to FIG. 1. Now, it is assumed 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, the clay pot 23 on the top plate 7 is heated, and the temperature inside the heating unit 2 also rises rapidly, and when the temperature inside 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 as described above (at time t1 in FIG. 1).

As a result, when the temperature inside the heating unit 2 is lowered 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 a decrease of 0.1 KW from the previous high output (Fig. At time t2), the halogen lamp 3 is switched between a high output state and a low output state according to the turning on and off 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 switches the halogen lamp 3 to the low output state as described above, and starts the time counting operation. However, when the output of the halogen lamp 3 is reduced at the beginning of heating,
Like the pot 26 with good thermal conductivity, the amount of heat generated by the halogen lamp 3 is smaller than the amount of heat radiated from the heating unit 2, so the inside of the heating unit 2 drops to the lower limit set temperature within a predetermined time T. To do. Therefore, the microcomputer 18 maintains the high / low switching control state in which the output of the halogen lamp 3 is controlled by switching between high and low.

However, as the heating of the clay pot 23 progresses, the thermal conductivity of the clay pot 23 is low, and the clay pot 23 has a good heat retaining property, and unlike the cooking of boiled food, the heat is not taken away by the evaporation of water. Even if the output of the halogen lamp 3 is low, the amount of heat generated by the halogen lamp 3 exceeds the amount of heat released by the heating unit 2.

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

Therefore, the microcomputer 18 is
At time t5, when the halogen lamp 3 is switched to the low output state and the timekeeping operation is started,
From 5 onward, the microcomputer 18 does not receive the ON signal from the thermostat 8 for a predetermined time T.
Will end counting (at this point in time in FIG.
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 is completed. Due to this reduction in the output of the halogen lamp 3, the temperature inside the heating unit 2 gradually decreases thereafter, and as a result, the temperature inside the heating unit 2 does not rise abnormally, and the top plate 7 and the halogen lamp 3 are prevented. There is no risk that the valve will exceed the heat resistant temperature.

After that, when the inside of the heating unit 2 is lowered to the lower limit set temperature, the thermostat 8 is turned on (at this time point is shown by t7 in FIG. 1). Then, the microcomputer 18 returns the output of the halogen lamp 3 to the high output state (2 kW in this case) at the beginning of energization, and thereafter, when the energization starts, the same control as the control, that is, the output of the halogen lamp 3 is turned on / off. High / low switching control is performed according to the level. When the thermostat 8 is not turned on within the predetermined time T after the halogen lamp 3 is switched to the low output state by turning off the thermostat 8, the microcomputer 18 outputs the output of the halogen lamp 3 in the same manner as described above. Repeat to reduce 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. Therefore, the output of the halogen lamp 3 is automatically adjusted to balance the absorbed heat amount of the cooking container. It can be adjusted. Therefore, when cooking using the clay pot 23, the heating unit 2 is operated when the halogen lamp 3 is in a low output state.
It is possible to prevent the situation where the internal temperature does not drop to the lower limit set temperature but rises to the utmost.

Even if the halogen lamp 3 is switched to the low output state, if the temperature inside the heating unit 2 rises, the output of the halogen lamp 3 is kept constant after a predetermined time T elapses. Output value (0.5
Since it is reduced to KW), it is possible to prevent the occurrence of a serious accident that damages the bulb of the halogen lamp 3 and the top plate 7. In this case, the halogen lamp 3
Was turned off, and then the thermostat 8 was turned on again t7
It is conceivable to re-energize the halogen lamp 3 at that time, but if this is done, the top plate 7 that had been brightly illuminated by the halogen lamp 3 will become completely dark, and the user will be notified of the end of cooking. Misidentify,
There is a risk of leaving the "off" switch 13 without operating it. Also, even if you do not make such a false positive,
There is a problem that it takes longer time to finish cooking,
In the present embodiment, such a problem does not occur.

10 and 11 show a second embodiment of the present invention. The second embodiment is different from the first embodiment in that the output of the halogen lamp 3 is reduced to a constant low output value of 0.5 KW, and then a predetermined time T1 (for example, several minutes) elapses. If the thermostat 8 is not turned on by then, the halogen lamp is turned off when the time T1 has passed.

That is, in FIG. 10, the thermostat 8 does not turn on until the predetermined time T elapses after the halogen lamp 3 is switched to the low output state, and the output of the halogen lamp 3 is reduced to 0.5 KW at time t6. It has been done. Then, the microcomputer 18 starts counting the elapsed time from the time t6. And
As shown by the chain double-dashed line in FIG. 1, when the thermostat 8 is turned on within the time T1 (this time is shown by t8 in FIG. 10), the time t1 elapses at the time t9 and the first embodiment and Similarly, the output of the halogen lamp 3 is returned to the high output state (2 KW in this case) at the beginning of energization, and thereafter, the high / low switching control state in which the output of the halogen lamp 3 is switched between high and low in accordance with ON / OFF of the thermostat 8 is maintained. When the thermostat 8 is turned off, the halogen lamp 3
When the thermostat 8 is not turned on within the predetermined time T after the switch to the low output state, the microcomputer 18 repeats to decrease 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 remains in the off state without turning on within the time T1 from the time t6, the microcomputer 18 determines that the time T1 is Time t
The halogen lamp 3 is turned off at 9 and the abnormality notification lamp 27 provided on the operation panel 11 as shown in FIG.
Light up. Then, the user uses this abnormality notification lamp 2
It is noticed that the inside of the overheating unit 2 has been overheated by turning on 7, and, for example, the "input down" switch 15 is operated to reduce the output of the halogen lamp 3, and the "on" switch 12 is operated again to restart the heating. To do.

As described above, according to this embodiment, even if the output of the halogen lamp 3 is reduced to a low output value, the halogen lamp 3 is turned off when the thermostat 8 does not turn on within the predetermined time T1. Therefore, the temperature inside the heating unit 2 is not left at the lower limit set temperature or higher for a long time, and the halogen lamp 3 and the top plate 7 can be protected perfectly. That is, even if the output of the halogen lamp 3 is reduced to a constant low output value (0.5 KW), the thermostat 8 does not turn on, that is, the temperature inside the heating unit 2 is left as it is for a long time at the lower limit set temperature or higher. Means that. The bulb of the halogen lamp 3 and the top plate 7 are adversely affected depending on the time. However, in this embodiment, the heating unit 2
There is no risk that the temperature inside will remain above the lower limit 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 the lamp heater is switched to the low output state, the output of the lamp heater is further lowered to a constant low level. With the configuration in which the output value is lowered, it is possible to prevent the ambient temperature of the lamp heater from being abnormally high even if the cooking is performed using a cooking container having good thermal conductivity and heat retention.

In the electric cooker according to the second aspect, when the temperature detecting means detects the lower limit set temperature within a predetermined time after the output of the lamp heater is lowered to a constant low output value, the lamp heater is energized. When the temperature detecting means does not detect the lower limit set temperature within a predetermined time, the same control as the accompanying control is performed.
Since the lamp heater is configured to turn off the power, the lamp heater will not be turned off if it is not left at a low output and the temperature detection means does not detect the lower limit set temperature within the predetermined time. Since the electric power is supplied to the lamp heater, there is no risk of the lamp heater being left at a high temperature for a long time, and the lamp heater and the top plate can be protected completely.

[Brief description of drawings]

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

[Figure 2] Partial vertical section side view when heating a clay pot

FIG. 3 is a diagram corresponding to FIG. 1 in the case of heating a normal metal pan.

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

FIG. 5 is a perspective view showing an outline of the entire electric cooker.

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

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

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

FIG. 9 is an electrical circuit configuration diagram.

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

FIG. 11 is a view corresponding to FIG.

FIG. 12 is a view 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 detection means), and 18 is a microcomputer (control means).
Is.

Claims (2)

[Claims] 1. A lamp heater serving as a heat source, the upper part of which is covered with a top plate to heat a cooking container such as a pot placed on the top plate, wherein temperature detecting means for detecting an ambient temperature of the lamp heater. And when the lamp heater is energized, the lamp heater is switched from a high output state to a low output state when the temperature detecting means detects the upper limit set temperature and a low output state to a high output state when the lower limit set temperature is detected. And a control means for controlling so as to gradually decrease the output value in the high output state each time the upper limit set temperature is detected, and the control means detects the upper limit set temperature by the temperature detection means, When the temperature detecting means does not detect the lower limit set temperature within a predetermined time after switching the output to a low output state, the output of the lamp heater is further increased. An electric cooker configured to reduce 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 when the temperature detecting means detects the lower limit set temperature within a predetermined time, returns the lamp heater to a high output state and energizes it. The electric cooking according to claim 1, wherein the electric power is controlled in the same manner as the control at 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.