JPH02197723A - Electric cooking apparatus - Google Patents

Abstract

PURPOSE:To minimize the number of times of feeding and cutting off a current flowing to a lamp heater or the number of times of a great change in a current by gradually reducing the output from the lamp heater in the range of a fixed output value or more each time a temperature detecting means for detecting the atmospheric temperature of the lamp heater detects a predetermined temperature or higher in and after a predetermined period of time. CONSTITUTION:In the title cooking apparatus, a temperature in a closed heating unit 2, namely, the atmospheric temperature of halogen lamps 3 is detected by a thermostat 8. Furthermore, a controller is programmed so as to gradually reduce the output from the halogen lamps 3 by 5% of their maximum output at each step during an ON period subsequent to each occasion that the thermostat 8 detects a predetermined temperature or higher to be turned OFF in and after a predetermined period of time. According to this constitution, the output from the lamps 3 is changed over from a high level to a low level in accordance with the ON/OFF of the thermostat 8. However, since the heating rate of the lamps 3 gradually approximates the amount of heat which is absorbed to a pan and the like, the period of changing over the output from the lamps 3 becomes remarkably longer as compared with conventional periods and, in the case where the heating rate of the lamps 3 is balanced with the amount of heat to be absorbed by the pan and the like, the state of a high output is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [First aspect of the invention] (Field of industrial application) The present invention relates to an electric cooker using a lamp heater as a heat source.

(Prior Art) In this type of electric cooker that has been considered in the past, a halogen lamp is generally used as a lamp heater, and the heat generated by this halogen lamp is used to heat the object to be heated. .

Specifically, a heating unit is constructed by covering the periphery and bottom of a group of multiple 7~logen lamps with a heat insulating material, and further covering the top surface of the heat insulating material with a translucent top plate made of heat-resistant glass or the like. . Then, a cooking container such as a pot is placed on the top plate, and the object placed in the pot is cooked using the heat emitted by the halogen lamp.

In such an electric cooker, the heat emitted from the nozzle lamp is transmitted to the pot (an object to be heated) by radiation or conduction via the top plate. The heat capacity of this top plate is relatively large, and the temperature of the top plate does not rise easily at the start of heating, resulting in poor heat conduction through the top plate and poor rise in temperature of the cooking container. Therefore, conventionally, high output (2KW) lamps have been used as 10-gen lamps so that the temperature of the top plate can rise quickly.

On the other hand, in this electric cooker, in order to increase thermal 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 a halogen lamp is continuously energized, the ambient temperature of the halogen lamp, that is, the air temperature inside the heating unit, gradually rises, and the heat resistance limit temperature (85
(approximately 0℃).

(Problem to be Solved by the Invention) Therefore, in conventional electric cookers, a thermostat is provided as a temperature detection means for detecting the temperature inside the heating unit, and when the inside of the heating unit reaches a predetermined temperature, the halogen lamp is turned off. I tried to turn off the electricity. However, with this type, when the halogen lamp is turned on again, the temperature inside the heating unit immediately rises and the halogen lamp is turned off again, which is a situation that occurs repeatedly in short cycles. The problem arises that the lifespan of the product is shortened. For example, as mentioned above, the heat emitted by a halogen lamp is transmitted to the pot by radiation or by conduction through the top plate, but pots with poor heat absorption properties, such as pots with good light reflectivity such as those made of aluminum, Since the radiant heat is reflected by the halogen lamp, the heat is trapped inside the heating unit, and as soon as the halogen lamp is turned on, the temperature rises to the thermostat's off operating temperature.As a result, the halogen lamp is turned on frequently. The power is cut off (see Figure 9). In addition, even with a pan with a darkened bottom and good heat absorption, the 7u disconnection occurs repeatedly in a fairly short period, although this is not as frequent as with a pot with poor heat absorption.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to reduce the number of times the lamp heater is turned on and off, or the number of times the current of the lamp heater changes greatly, thereby extending the life of the lamp heater. The goal is to provide electricity and cooking equipment that can be used to increase the cost of cooking.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the electric cooker of the present invention is provided with temperature detection means for detecting the ambient temperature of the lamp heater, and this temperature detection means The lamp heater is provided with output control means for gradually decreasing the output of the lamp heater within a range of a predetermined output value or higher each time a predetermined temperature or higher is detected after a certain period.

(Function) When the lamp heater is energized to start heating, the ambient temperature of the lamp heater gradually rises. Then, when the temperature detection means detects a temperature equal to or higher than a predetermined temperature after a predetermined time, the output of the lamp heater is reduced each time the temperature is detected. This means that the output (calorific value) of the lamp heater is automatically adjusted in a direction that balances the amount of heat taken by the object to be heated (such as a pot containing the object to be cooked). Therefore, the number of times the lamp heater is turned on and off, or the number of times the current of the lamp heater increases or decreases significantly, is reduced, resulting in a longer life.

Furthermore, since the output of the lamp heater does not fall below a certain level, the lamp heater has good heating performance even when water is added to the lamp while cooking, for example.

(Example) An example of the present invention will be described below based on FIGS. 1 to 8.

First, as shown in FIG. 4, an outer frame 1 of an electric cooking appliance is formed in the shape of a flat rectangular box, and heating units 2 are disposed at, for example, three positions inside the outer frame 1. As shown in FIGS. 5 and 6, these heating units 2 are constructed by sandwiching a plurality of halogen lamps 3, which are lamp heaters, between upper and lower oval heat insulators 4.5, for example, four halogen lamps. appeal heat body 5
is fixed to the inner bottom surface of the outer frame 1 by a saucer 6.

The upper surface of the heating element 4 of each heating unit 2 is covered with a top plate 7 made of heat-resistant glass or the like with a translucent property H.
The inside of the heating unit 2 is hermetically sealed. The temperature within this sealed heating unit 2, and therefore the ambient temperature of the halogen lamp 3, is outputted to a thermostat 8 as temperature detection means. This thermostat 8 includes a heat-sensitive part formed by disposing a metal rod (not shown) that expands and contracts according to temperature changes in a metal outer tube 9a, and a switch part that is turned on and off by the expansion and contraction of the metal rod of the heat-sensing part 9. 10, the heat sensitive part 9 is arranged inside the heating unit 2, and the switch part 10 is arranged outside the heating unit 2. The thermostat 8 is designed to turn off at temperatures above 750'C. Also,
An operation panel 11 is provided on the outer frame 1 in parallel with the Totsubu 1 notebook 7. This operation panel 11 has a seventh
As shown in the figure, "man" and "off" switches 12 and 13 for starting and stopping heating, a halogen lamp 3
[Manpower upJ and "input d" for adjusting the calorific value (between human power)
OwnJ switches 14 and 15 are provided, as well as a plurality of light emitting diodes 16 for displaying the magnitude of input to the halogen lamp 3. still,
The above various switches 12 to 15 and light emitting diode 16
are provided in each heating unit 2 in a one-to-one relationship, but in the drawing, only one corresponding to one heating unit is shown for convenience.

The electric circuit configuration of this electric cooker is as shown in FIG. 8 (only one heating unit is shown).Heating unit 2
The four halogen lamps 3 are connected in parallel to a power source 17, and the halogen lamps 3 are controlled to be turned on and off by a microcomputer 18.

The microcomputer 18 controls various electrical components included in the electric cooker, and receives signals from the thermostat 8 and various switches 12 to 15, and switches the light emitting diode 16 on and off according to the input signal. At the same time, a triac 19 connected in series with the three groups of halogen lamps is controlled via a drive circuit 20, thereby controlling the three groups of /10 gen lamps to be turned on and off. In this case, when the "person" switch 12 is operated, the microcomputer 18 keeps the halogen lamp 3 energized until the "off" switch 13 is operated.
Output (heat amount) of halogen lamp 3 while energized
is a high output during the ON period of the thermostat 8, and a low output during the OFF period of the thermostat 8, for example, the maximum output (2K
In this embodiment, control is performed within the range of 1/3 to 2/3 of W) to IKW. The output of the halogen lamp 3 is controlled by so-called phase control that controls the duty ratio of the triac 19. And thermostat 8
The output of the halogen lamp 3 during the ON period can be set by both the input switches 14 and 15, and the set output is switched by a signal from the thermostat 8. In other words, after a predetermined period, the microcomputer 18 turns off the halogen lamp 3 in the next ON period every time the thermostat 8 detects a predetermined temperature or higher and turns off after the start of cooking in this embodiment. The output of 596 (0, I K
It is programmed to gradually decrease by W). In this case, the output of the halogen lamp 3 is gradually decreased at a constant output value, for example, in the range of 1.6KW or more.
It is programmed so that when the temperature drops to W, even if the thermostat 8 is turned off thereafter, it remains at 1.6 KW during the on period. In this way, the microcomputer 18 functions as an output control means for controlling the output of the halogen lamp 3.

Next, the operation of the above structure will be explained with reference to the time charts of FIGS. 1 and 2.

The time charts in Figures 1 and 2 show the case where water is heated as a heating material (load) in a pot with a good heat absorption rate and a pot with a poor heat absorption rate, respectively. be.

First, to explain the case of a pot with good heat absorption rate using FIG.
vn Operate the J switch 15 to set the output (at high output) of the halogen lamp 3.

Now, set the output of halogen lamp 3 to its maximum output (2KW)
Suppose you set it to . Then, the heat emitted from the halogen lamp 3 is transferred directly to the pot placed on the top plate 7 by radiation or by conduction via the top plate 7, heating the pot while increasing the temperature inside the heating unit 2. also rises rapidly. When the temperature inside the heating unit 2 reaches a predetermined temperature or higher, the thermostat 8 is turned off (at time T8 in Figure 511), and upon receiving this off signal, the microcomputer 18 operates to set the halogen lamp 3 to low output. When the temperature inside the heating unit 2 drops to a certain level due to this large drop in the output of the halogen lamp 3, the thermostat 8 turns on (at time T2 in FIG. 1), and upon receiving this on signal, the microcomputer 18 turns the halogen lamp 3 on. It operates as output. At this time, the microcomputer 18 lowers the output of the halogen lamp 3 by 0.0 compared to the previous high output. The phase is controlled via the triac 19 so as to reduce the IKW, and as a result, the halogen lamp 3 generates heat with its output reduced from 2KW to 1.9KW. Although the temperature inside the heating unit 2 starts to rise again due to the high output heat generated by the halogen lamp 3, the output of the halogen lamp 3 is reduced by one step, so in the example of FIG. The amount of heat generated is almost in balance with the amount of heat absorbed by the pot. Therefore, from then on, the temperature inside the heating unit 2 will no longer rise to the temperature at which the thermostat 8 turns off, and the halogen lamp 3 will be continuously energized with an output of 1.9 KW. Then, after heating the cooking container for the desired time, turn off the switch 13.
Operate to finish cooking.

Next, the case of a pot with poor heat absorption rate will be explained with reference to FIG. 2. Assume that the output of the halogen lamp 3 is set to 2 KW and cooking is started in the same manner as described above. Then, the pot on the top plate 7 is heated, and the temperature inside the heating unit 2 (7) also 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 turned off. The output of is greatly reduced to IKW (at time T1 in FIG. 2). As a result, when the temperature inside the heating unit 2 drops to a certain level, the thermostat 8 is turned on, and the halogen lamp 3 becomes 0.0 lower than the previous high output. IK
Heat is generated at an output of 1.9 KW, which is a decrease in W (time T2 in Figure 2). However, in the case of Fig. 2, the output of the halogen lamp 3 is 1.9KW because the heat absorption rate of the pot is poor.
Even if the amount of heat generated by the halogen lamp 3 is still greater than the amount of heat absorbed by the pot, etc., the temperature inside the heating unit 2 rises to the predetermined temperature again, and the thermostat 8 is turned off again (point T in FIG. 2), and the output of the halogen lamp 3 is reduced to IKw. 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 to generate heat at an output of 1.8 KW, which is 0° IKW lower than the output at the previous high output ( (Figure 2 at T4).

In this way, each time the thermostat 8 is turned off, the output of the halogen lamp 3 at high output is gradually decreased by 0, IKW until it reaches 1.6 KW. If the output of the halogen lamp 3 still exceeds the amount of heat taken by the pot etc. even if the output is reduced to 1.6KW, the thermostat 8 will continue to turn on and off, but the output of the halogen lamp 3 will be taken away by the pot etc. Since it approaches the amount of heat, its on/off cycle becomes longer.

As described above, the thermostat 8 prevents the temperature inside the heating unit 2 from exceeding the heat resistance limit of the halogen lamp 3.1. While being controlled, the output of the halogen lamp 3 is adjusted and cooking is performed. Then, after heating the cooking container for a desired time, the user operates the "off" switch 13, thereby finishing the cooking.

In this way, according to this embodiment, each time the thermostat 8 detects a predetermined temperature (turns off), the output of the halogen lamp 3, that is, the amount of heat generated, is gradually reduced one step at a time in a direction that balances the amount of heat absorbed by the pot, etc. Automatically: J! The output of the halogen lamp 3 is switched between high and low as the thermostat 8 is turned on and off, but the cycle is different from the conventional one because the amount of heat generated by the halogen lamp 3 gradually approaches the amount of heat absorbed by a pot, etc. If the former becomes much longer than the latter and the former is in balance with the latter, the high output state remains. Therefore, the number of times the output of the halogen lamp 3 is switched high and low is extremely reduced, the number of large fluctuations in the value of the current flowing through the halogen lamp 3 is extremely reduced, and the life of the halogen lamp 3 can be extended. Moreover, since the high output period of each halogen lamp 3 is longer, cooking can be done faster.

Furthermore, according to this embodiment, after the output value of the halogen lamp 3 at high output has decreased to 1.6 KW, it will not be reduced any further, so that, for example, when pouring water while cooking boiled food, or after the end of heating cooking, Even if a new pot is placed on the top plate 7 without operating the OFF J switch 13, the heating performance is good.This will be explained in detail with reference to Figure 3. This figure shows the case where 2g of water is poured into a pot, the water in one pot is heated until it boils, and then another pot is heated until it boils without operating the "off" switch 13. , in the first pot it takes 656 hours for the water to boil.
It took a few seconds, but in the next pot the water was ready in 582 seconds! 11f!
It is understood that L means good heatability. If the minimum output at high output of halogen lamp 3 is not regulated,
With a pot with poor heat absorption, the output value at high output may drop to about IKW, and even if you try to heat a pot with good heat absorption without operating the "off" switch 13 after that, the IKW will still be low. Therefore, good heating properties as in this example cannot be obtained.

In the above embodiment, each time the thermostat 8 is turned off after the start of heating cooking, the output of the halogen lamp 3 during the subsequent high output is reduced one step at a time. The output of the halogen lamp is kept constant for 5 minutes regardless of whether the thermostat 8 is turned off, and each time the thermostat 8 is turned off after 5 minutes, the output of the halogen lamp 3 is decreased by one step (1
You can also make 4.

Further, in the above embodiment, the halogen lamp 3 is energized with the IKW output even when the thermostat 8 is off, but the halogen lamp 3 may be turned off.

[Effects of the Invention] As is clear from the above description, according to the electric cooker of the present invention, from a predetermined time onwards, each time the temperature detection means detects that the ambient temperature of the lamp heater has become equal to or higher than the predetermined temperature, By gradually reducing the output of the lamp heater in a range above a certain output value, the output of the lamp heater can be adjusted to reduce the output of the heated object, etc. while preventing the ambient temperature of the lamp heater from exceeding the heat-resistant limit temperature of the lamp heater. As a result, the number of times the lamp heater is turned on and off can be reduced, or the number of large changes in the current flowing through the lamp heater can be reduced, and the life of the lamp heater can be extended. Moreover, since there is a set limit for the gradual decrease in the lamp heater output, even if you add water during cooking or start a new cooking process without turning off the heat, the result will still be good. It exhibits heatability and has an excellent effect of being able to prevent the problem of excessively long cooking time.

[Brief explanation of the drawing]

1 to 8 show an embodiment of the present invention,
Figure 1 is a time chart showing the temperature changes of each part in the case of a pot with good heat absorption rate, Figure 2 is a time chart showing the temperature changes of each part in the case of a pot with poor heat absorption rate, and Figure 3 is the cutting operation. Figure 2 is a diagram equivalent to the experimental results when changing the heating pot without heating, Figure 4 is a perspective view of the entire electric cooker, Figure 5 is an enlarged vertical sectional view of the heating unit, and Figure 6 is FIG. 7 is a partially enlarged front view of the operation panel, FIG. 8 is an electric circuit (with I1111 configuration), and FIG. 9 is an enlarged perspective view of the heating unit i with the top plate removed. This is a diagram equivalent to Figure 2. In the figure, 2 is a heating unit, 3 is a halogen lamp (lamp heater), 4.5 is an upper and lower insulator, 7 is a top plate, 8 is a thermostat (temperature detection means), 18 is a microcomputer (output control means). Applicant: Toshiba Corporation

Claims (1)

[Claims] 1. A lamp heater is used as a heat source, the upper part of which is covered with a translucent top plate, and an object to be heated placed on the top plate is heated and cooked, and the ambient temperature of the lamp heater is temperature detection means for detecting the temperature, and output control means for gradually decreasing the output of the lamp heater within a range of a predetermined output value or more each time the temperature detection means detects a predetermined temperature or higher after a predetermined time. An electric cooker characterized by: