KR930004202B1 - Electric cooking appliance - Google Patents

Abstract

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Description

Electric cooker

1 to 8 show an embodiment according to the present invention,

1 is a time chart showing the temperature change of each part in the case of a pot having good heat absorption rate.

2 is a time chart showing the temperature change of each part in the case of a pot with poor heat absorption rate.

FIG. 3 is a diagram corresponding to FIG. 2 showing experimental results when the pot is changed without a conversion operation.

4 is a perspective view of the entire electric cooker.

5 is an enlarged longitudinal sectional view of the heating unit.

6 is an enlarged perspective view of the heating unit showing a state where the top plate is removed.

7 is a partially enlarged front view of the operation panel.

8 is an electrical circuit diagram,

9 is a view corresponding to FIG. 2 in the conventional electric cooker.

* Explanation of symbols for main parts of the drawings

2: heating unit 3: halogen lamp (lamp heater)

4,5: upper and lower insulators 7: top plate

8: thermostat (temperature detection device) 18: microcomputer (output control device)

The present invention relates to an electric cooker using a lamp heater as a heat source.

In this type of electric cooker that has been proposed in the related art, a halogen lamp is usually used as a lamp heater, and the heated object is heated by heat generated by the halogen lamp.

Specifically, the heating unit is formed by covering the periphery and the bottom of the plurality of halogen lamps with an insulator, and the top surface of the insulator is covered with a top plate having a property of passing light such as heat-resistant glass. A cooking vessel such as a pot is placed on the top plate, and the heated object is heated and cooked in the pot by the heat generated by the halogen lamp. In such an electric cooker, the heat generated from the halogen lamp is transferred to the pot (heated object) as radiant heat or as conduction heat through the top plate. Since the heat capacity of the top plate is relatively large, the top plate temperature does not easily rise at the start of heating, so heat conduction through the top plate cannot be expected, and the rate of increase of the cooking vessel temperature decreases. Therefore, a lamp of high power (2KW) has been used as a halogen lamp since the past.

On the other hand, in such an electric cooker, the inside of the heating unit is configured as a closed space by closely contacting the heat insulator and the top plate in order to increase the thermal efficiency. Therefore, when the halogen lamp is continuously energized, the ambient temperature (ambient temperature) of the halogen lamp, that is, the air temperature inside the heating unit is gradually increased, and the heat resistance limit temperature (about 850 ° C.) of the quartz glass tube forming the bulb of the halogen lamp is gradually increased. Will be exceeded. Therefore, in the conventional electric cooker, the thermostat is provided as a temperature detection device for detecting the temperature inside the heating unit, so that the electricity supply to the halogen lamp is stopped when the inside of the heating unit reaches a predetermined temperature.

However, in such a cooker, as shown in FIG. 7, when the halogen lamp is re-energized, the internal temperature of the heating unit is raised immediately, and the state in which the power supply to the halogen lamp is stopped again frequently occurs in a short cycle. There is a problem of shortening.

For example, as described above, the heat generated by the halogen lamp is transmitted as radiant heat to the pot, or as conduction heat through the top plate, and reflects radiant heat in the case of a pot having poor heat absorption, for example, a pot having good light reflectivity. Therefore, heat is easily accumulated inside the heating unit by the reflected heat, and when the halogen lamp is energized, the temperature is immediately raised to the thermostat-off operating temperature, and as a result, the halogen lamp is frequently energized (see FIG. 10).

In addition, even if the bottom of the pot is black, the heat-absorbing pot is not as frequent as the pot of heat-absorbing, as shown in Figure 9, but the breakthrough is repeated in a fairly short cycle.

On the other hand, in Figs. 9 and 10, when the room temperature is 23-25 ° C. and 2 liters of water are heated, the thermostat is turned on and off, and the thermostat of the thermostat (refer to the explanation later). The relationship between the surface temperature of and the bulb surface temperature of the halogen lamp is shown.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned facts, and its object is to reduce the number of energization and disconnection of the lamp heater, or to reduce the number of times the value of the current flowing into the lamp heater is greatly changed, thereby prolonging the life of the lamp heater. An electric cooker can be provided.

In order to achieve the above object, the electric cooker according to the present invention is provided with a temperature detecting device for detecting an ambient temperature of a lamp heater, and when the temperature detecting device detects that the temperature is higher than a predetermined temperature after a predetermined time, the lamp described above every time. An output control device will be installed to gradually reduce the heater output.

When the lamp heater is energized by the operation at the start of heating, the ambient temperature of the lamp heater is gradually increased.

After the predetermined time, if the temperature detecting device detects that the temperature is higher than or equal to the predetermined temperature, the output of the lamp heater gradually decreases every time it is detected. This means that the lamp heater output (heating amount) is automatically adjusted to match the amount of heat absorbed by the heated object (pot with the cooked material). Therefore, the lifespan is long because the number of times before the lamp heater is disconnected or the number of times that the current flowing through the lamp heater is greatly increased or decreased is reduced.

In addition, since the lamp heater is not below a constant output value, for example, heating is good even when water is added while cooking.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS. 1 to 8.

First, as shown in FIG. 4, the outer circumferential surface 1 of the electric cooker is formed in a flat rectangular shape, and is disposed in the heating unit 2 in three places, for example. As shown in FIGS. 5 and 6, these heating units 2 support a plurality of halogen lamps 3, which are lamp heaters, for example, four by elliptical upper and lower insulators 4 and 5, so that the floor is supported. The lower insulator (5) having the bearing is fixed to the inner bottom surface of the outer circumferential surface (1) by the receiving plate (6).

And the upper surface of the upper heat insulating body 4 of each heating unit 2 is covered with the top plate 7 which can pass the light of one heat-resistant glass, etc. This top plate 7 is an upper heat insulating body ( The inside of the heating unit 2 is sealed by being in close contact with 4). The temperature inside the sealed heating unit 2, that is, the ambient temperature of the halogen lamp 3 is a thermostat 8, which is a temperature detecting device, is a metal rod (not shown) that can be stretched by a temperature change inside the metallic exterior 9a. And a switch unit 10 on which the metal rod of the heat sensing unit 9 is turned on and off according to expansion and contraction, and the heat sensing unit 9 includes a heating unit 2. It is disposed inside and the switch unit 10 is disposed outside the heating unit (2). In addition, this thermostat 8 is comprised so that it may turn off when it becomes 750 degreeC or more by design.

Moreover, on the outer peripheral surface 1, the operation panel 11 is provided in parallel with the top plate 7. As shown in Fig. 7, the operation panel 11 includes the switches 12 and 13 of "on" and "off" for heating start and stop, and the amount of heat generated (input amount) of the halogen lamp 3. Each switch 14 and 15 of "input up" and "input down" for adjusting is provided, and at the same time, a plurality of light emitting diodes 16 for displaying the input amount to the halogen lamp 3 are provided. have.

On the other hand, the various switches 12 to 15 and the light emitting diodes 16 are provided in each heating unit 2 one by one, but the drawings show only one heating unit for convenience. The electric circuit configuration of this electric cooker is shown in FIG. 8 (only one heating unit is shown), and the four halogen lamps 3 of the heating unit 2 are connected in parallel to the power source 17. The halogen lamps 3 are integrally controlled by the microcomputer 18.

The microcomputer 18 controls various electric components provided in the electric cooker, and receives signals from the above-mentioned thermostat 8 and various switches 12-15 and according to the input signal. By controlling the triac 19 connected in series with the halogen lamps 3 through the driving circuit 20 at the same time as energizing the above-described light emitting diode 16, the halogen lamps 3 are integrally controlled. .

In this case, when the "on" switch 12 is operated, the microcomputer 18 keeps the halogen lamp 3 in the energized state until the "off" switch 13 is operated. In this energized state, the halogen lamp 3 is operated. (3) The output (heating amount) is a high output when the thermostat 8 is on, and a low power (eg, 1 / 3-2 / 3 of the maximum output (2KW) when the thermostat 8 is off). , 1KW in this embodiment. The output control of the halogen lamp 3 is performed by the duty ratio control of the triac 19, so-called phase control.

The halogen lamp 3 output when the thermostat 8 is on can be set by both the switches 14 and 15 of "input up" and "input down" while the set output is It can be converted by the signal from the stat (8).

That is, according to the present embodiment, the microcomputer 18 detects that the thermostat 8 becomes over a predetermined temperature after the start of heating after a predetermined time, and then the halogen lamp 3 during the next on period until it is turned off. The output is programmed to gradually decrease by 5% (0.1 KW) of its maximum output (2 KW). In this case, the halogen lamp 3 output is gradually lowered within a certain output value, for example, in the range of 1.6KW or more, and when lowered to 1.6KW, thereafter, the thermostat 8 is programmed to turn on again to 1.6KW in the next on-time even if the thermostat 8 is turned off. have. Thus, the microcomputer 18 is made possible as an output control apparatus which controls the halogen lamp 3 output.

Next, the operation of the above configuration will be described with reference to the time charts of FIGS. 1 and 2. The time charts of FIGS. 1 and 2 show a case where two liters of water are heated in a pot having a high heat absorption rate and a pot having a low heat absorption rate.

First, in accordance with FIG. 1 illustrating a pot having high heat absorption rate, the "on" switch 12 or the "input up" switch 14 or the "input down" switch 15 may be operated to operate the heating cooking. To set the output (at high output) of the halogen lamp 3.

For example, if the halogen lamp 3 is set to its maximum output (2 KW), the heat generated from the halogen lamp 3 is directly or as radiant heat to the pot lying on the top plate 7 or the top plate 7. The pot is heated by conduction heat through, while the temperature inside the heating unit 2 also rises rapidly.

When the temperature inside the heating unit 2 becomes higher than the predetermined temperature, even when the thermostat 8 is turned off (Fig. 1, T ₁ ), the microcomputer 18 outputs the halogen lamp 3 according to the off signal. It is operated to lower. When the temperature inside the heating unit 2 drops to a certain temperature according to the output of the halogen lamp 3, the thermostat 8 is turned on (Fig. 1 T ₂ time point), and the microcomputer according to the on signal is used. 18 is operated to increase the output of the halogen lamp 3. At this time, the microcomputer 18 controls the phase of the halogen lamp 3 through the triac 19 so that the output of the halogen lamp 3 is reduced to 0.1KW from the previous high output to be 1.9KW, so the halogen lamp 3 is lowered from 2KW to 1.9KW. Heat is generated. As the halogen lamp 3 heats again at high power, the temperature inside the heating unit 2 also rises again. However, since the output of the halogen lamp 3 decreases by one step, in the example of FIG. 1, the amount of heat generated by the halogen lamp 3 It is almost equal to the amount of heat absorbed by the pot.

Therefore, since then, the temperature inside the heating unit 2 will not rise to the off operation temperature of the thermostat 8, and the halogen lamp 3 will continue to energize with the output 1.9KW. After the cooking vessel is heated for a desired time, the cooking is completed by operating the " off " switch 13.

Next, a case where the pot has a poor heat absorption rate will be described with reference to FIG. 2, where the cooking of the heating is started by setting the output of the halogen lamp 3 as described above. Then, the pot on the top plate 7 is heated and at the same time the temperature inside the heating unit 2 rises rapidly. When the temperature inside the heating unit 2 reaches a predetermined temperature, the thermostat 8 is turned off and the halogen lamp 3 ) Is greatly reduced to ₁ KW (Fig. 2 T ₁ time point).

Accordingly, when the inside of the heating unit 2 is lowered to a certain temperature, the thermostat 8 is turned on, so that the halogen lamp 3 is energized to generate heat at an output of 1.9 KW, which is 0.1 KW lower than at the previous high output (FIG. 2 T ₂ time points).

However, in the case of FIG. 2, since the heat absorption rate of the pot is low, even if the halogen lamp 3 is lowered to the output 1.9KW, the calorific value of the halogen lamp 3 is still larger than the amount of heat absorbed by the pot, and thus the heating unit 2 The internal temperature is raised to a predetermined temperature again, the thermostat 8 is turned off again (second time point T ₃ ), and the output of the halogen lamp 3 is lowered to 1 KW.

Accordingly, when the internal temperature of the heating unit 2 is lowered and the thermostat 8 is turned on again, the halogen lamp 3 is energized so as to generate heat of 1.8 kW, which is 0.1 kW lower than at the previous high power. ₄ time points).

In this way, whenever the thermostat 8 is turned off, the output of the halogen lamp 3 will fall by 0.1KW. If the output of the halogen lamp 3 is still exceeding the amount of heat absorbed by the pot, even if it falls to 1.6 KW, the thermostat 8 repeats the on and off, but the output of the halogen lamp 3 is absorbed by the pot. The on / off cycle is long because it is close to the amount of heat. In this way, while the temperature inside the heating unit 2 is controlled so that it may not become more than the heat-resistant limit temperature of the halogen lamp 3 by the thermostat 8, the halogen lamp 3 output is adjusted and heated and cooked. After the cooking vessel is heated for a desired time, the cooking is completed by operating the " off " switch 13.

As described above, according to the present invention, whenever the thermostat 8 detects a predetermined temperature (off operation), the output of the halogen lamp 3, that is, the amount of heat generated is decreased by one step, and is adjusted to match the amount of heat absorbed by the pot. As the thermostat 8 is turned on and off, the halogen lamp 3 is repeatedly converted to high power and low power, but the cycle is conventional because the halogen lamp 3 output gradually approaches the amount of heat absorbed by the pot. The period is extremely long compared to the product, and high power is maintained when the former and the latter become matched.

Therefore, the number of times that the halogen lamp 3 is converted to high output and low output is greatly reduced, and the number of times that the value of the current flowing through the halogen lamp 3 is greatly converted is also extremely reduced, and the lifetime of the halogen lamp 3 is long. In addition, since the time per high output period of the halogen lamp 3 is long, heating can be performed more quickly.

Further, according to the present embodiment, since the value at the time of high output of the halogen lamp 3 is lowered to 1.6 KW, it is no longer lowered. For example, when water is added while cooking food or after the completion of heating, Even when the other pot is placed on the top plate 7 without being operated, the " off " switch 13 can be heated. This will be described in more detail with reference to FIG. 3.

3, two liters of water are put in two pots and the electric cooker is heated to one pot until the water is boiled, and then the other pot is heated until the water is boiled without operating the "off" switch 13. One case is shown. As can be seen in FIG. 3, the first pot is 656 seconds when the water is boiling, but the next pot is 582 seconds and the water is boiling, and the heating is good. If the minimum output at the time of high output of the halogen lamp 3 is not regulated, the value at the time of high output may be reduced to about 1 KW in the case of a pot with low heat absorption, after which the heat without operating the " off " Even when the pot having high absorbency is heated, it is heated to 1KW as it is, and thus, good heatability cannot be obtained as in the present embodiment.

On the other hand, in the above embodiment, each time the thermostat 8 is turned off after the start of the heating cooker, the output of the halogen lamp 3 is reduced by one step at the time of subsequent energization. The halogen lamp output may be made constant regardless of the off operation of the thermostat 8 for 5 minutes, and the halogen lamp 3 output may be decreased by one step each time the thermostat 8 is turned off after 5 minutes.

In the above embodiment, the halogen lamp 3 is energized at an output of 1 KW while the thermostat 8 is off, but this may be cut off.

As can be seen from the above description, according to the electric cooker according to the present invention, whenever the temperature detecting device detects that the lamp heater atmosphere temperature becomes higher than the predetermined temperature after a predetermined time, the lamp heater output is in the range of the predetermined output value or more. By gradually reducing the temperature, the lamp heater output can be made close to the amount of heat absorbed by the heated object while keeping the lamp heater atmosphere temperature not exceeding the heat resistance limit temperature of the lamp heater. It is possible to reduce the number of times the flowing current is greatly increased and decrease, thereby extending the lamp heater life.

In addition, it is possible to exert good heating properties even when water is added during heating cooking or other heating cooking is performed without the "off" operation, and it is possible to prevent the time required for heating cooking from becoming too long in advance. There is.

Claims (1)

A case 1, a lamp heater 3 disposed in the case, a translucent top plate 7 disposed above the lamp heater, and a control device for controlling the energization of the lamp heater, An electric cooker for heating and cooking a heated object to be placed, comprising: a temperature detecting device (8) for detecting an ambient temperature of the lamp heater portion, wherein the control device is heated by a predetermined initial output of the lamp heater; After a predetermined time has elapsed since the start, whenever the temperature detecting device detects that the temperature rises above a preset temperature lower than the heat resistance limit temperature of the lamp heater, the lamp heater output is set to be lower than the initial output value and the initial output value. An electric cooker, characterized in that it is provided with an output control device (18) which gradually decreases between output values.

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