JPS6046786B2 - heating cooker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating cooker equipped with a temperature detection device and capable of maintaining heat at a set temperature, in which a timer device is switched in conjunction with the detection device. .

First, let's explain using a microwave oven as an example of a heating cooker.A microwave oven can perform the desired heating operation in a short time by simply setting a predetermined heating time on a timer device, and the heating cooking process can be completed quickly. As it has the advantage of being able to be carried out in an extremely clean environment, its popularity has gradually increased, and it now occupies a major position as a heating cooker in general households. In addition to cooking, there are also devices that reduce high-frequency output and enable long-term cooking, such as stewing.

By the way, among the various types of microwave ovens, the simplest one is one that allows cooking to be done within a set time by setting the timer device mentioned above. This guidebook allows the user to refer to the guidebook and perform the desired heating process. There is no need to set a timer device for the heating cooking time, which varies depending on the temperature state, and there are some that are equipped with a temperature detection device that operates to end the heating operation when a predetermined temperature is reached. For example, for dishes that contain a lot of water and require a considerable amount of time to reach a predetermined set temperature, such as the aforementioned stewed dishes, a timer device is used that only controls the simmering operation time after the set temperature is reached. A timer device is also being considered in which the timer device can be set to start operating when the temperature detection device detects the temperature. However, although these various shapes exist, each of them has its own shortcomings in terms of use.

In other words, the simple type uses the above-mentioned temperature detection stew (heat retention).
In the case of high-end models, even if it is possible to detect the temperature and then set the heat retention operation and time, the heating operation can be performed in the same way as the simple model, that is, by simply setting a timer device. Although it is easier to set a timer device for 1 minute, 2 minutes, and 3 minutes for cooking that is done most frequently, it is not possible to adjust the heating temperature individually. In addition, in the case of a timer device that allows you to set the cooking time equivalent to a simple type, and a temperature detection device, the above-mentioned warming operation cannot be performed. be. The present invention was made under these circumstances, and its purpose is to perform the functions that the conventional heating cookers described above had individually, that is, to start heating by starting the timer device from the start of heating. to carry out the cooking;
A heating cooking device with greatly improved usability that allows cooking to be performed until a predetermined set temperature is reached using a detection device, and in that case, allowing the subsequent warming operation time to be set using a timer device. It is about providing the equipment.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an external view of a microwave oven according to the present invention when the door is open, and FIG. 2 is a simplified wiring diagram of its power supply circuit.

In the figure, 1 is a main body, which has a heating chamber 2 inside which high-frequency energy is supplied, and a door 3 for opening and closing the opening of this heating chamber 2 is rotatably supported on the left side.
An operation panel 4 is provided on the right side, and the operation panel 4 is provided with, in order from the top, a cooking button 5, a temperature adjustment knob 6 for setting a predetermined temperature, and an operation knob 7a for a timer device 7. A temperature detector 8 is provided inside the chamber 2, the tip of which is inserted into the object to be heated 9, and the base end of the temperature detector 8 that is detachable from the inner wall of the heating chamber 2.

This temperature detection device 8 detects the temperature of the object to be heated using a temperature detection element and a thermistor 8a built into its tip, and as shown in FIG.
A parallel circuit is formed in the control circuit CON for operating the variable resistor 6a, which is rotatably operated by the temperature control knob 6, one end of which is connected to the DC power supply ■, and the other end connected to the base terminal of the transistor 10. and is grounded via a resistor 11. The transistor 10 has its collector terminal connected to the power supply V, its emitter terminal grounded via a resistor 12, and connected via a resistor 13 to the base terminal of a transistor 14. The emitter terminal of the transistor 14 is grounded, and the collector terminal is connected to the power supply V through a parallel circuit of the electromagnetic coil B1 of the relay B, a series circuit of a resistor 15, and a diode 16. The AC power supply E includes the first normally open switch A2 of the relay A, the high frequency generator 17, and the second normally open switch A2 of the relay A.
A parallel circuit of the normally open switch A3 and the cooking switch 5a,
A closed loop circuit constituted by a door switch 18 that responds to the opening and closing of the door 3, and a first switch 7b of the timer device 7.
1 Second switch 7C, its timer motor 7d, and relay C
A parallel circuit with electromagnetic coil C1, a series circuit of the third normally open switch A4 of relay A and the first changeover switch P1, a normally open switch B2 of relay B, and the first normally open switch of relay C. A parallel circuit with C2, a closed loop circuit constituted by the door switch 18, and a second changeover switch P2
A closed loop circuit is formed by the door latch switch 19, the normally closed switch B3 of the relay B, the electromagnetic coil A1 of the relay A, the second normally open switch A3 of the relay A, and the door switch 18. Timer device 7
The middle point of the connection between the second switch 7b and the third switch 7c and the middle point of the connection between the second changeover switch P2 and the door latch switch 19 are short-circuited, and the electromagnetic coil A1 of the relay A is short-circuited. A second normally open switch C3 of the relay C is interposed between the connection midpoint with the second normally open switch A3 and the normally open contact of the first changeover switch P1.

The second and third switches 7b and 7c of the timer device are closed by the setting operation of the timer device 7, and the first and second switches 7b and 7c are closed by the setting operation of the timer device 7.
With the installation of the temperature sensor 8 shown in FIG. 1, the connection state of the first changeover switch P1 is changed from the switch A4 to the switch C3 side, and the connection state of the changeover switches Pl and P2 is changed from the switch A4 to the switch C3 side, P2 is configured to be closed. In the power supply circuit configured as described above, first, when the temperature sensor 8 is not installed, the second
As shown in the figure, the changeover switch P1 is connected to the switch A4 side and the changeover switch P2 remains open, so the timer device 7 is operated and the switches 7b, 7c
is closed, the cooking switch 5 is turned on by operating the cooking button 5.
When a is closed, normally open switches A2 to A4 of relay A
is closed and held closed, and the high frequency generator 1
At the same time, the timer motor 7d starts rotating and starts extinguishing the set time.

At this time, switches C2 and C3 of relay C are also closed, but relay C in this case does not perform any special function. Therefore, when the detector 8 is not attached, the heating operation is performed for the time set by the timer device 7, similar to the operation of the simple type described above. Next, a case where the temperature sensor 8 is attached will be explained.

The changeover switch P1 is switched to the switch C3 side, and the changeover switch P2 is closed. If the cooking switch 5a is closed in this state without setting the timer 7, the normally open switches A2 to A4 of the relay A are closed and kept closed, and the power supply to the high frequency generator 17 is interrupted. will be started. Then, the temperature of the object to be heated rises due to the heating operation of the high frequency generator 17, and the combined resistance value of the thermistor 8a and variable resistor 6a in the detector 8 becomes below a predetermined value (that is, the object to be heated is at the set temperature ) and the transistor 10
, 14 are activated, a current flows through the electromagnetic coil B1 of the relay B, the switch B2 is closed, and the switch B3 is opened. Therefore, at this time, the power supply to the high frequency generator 17 is cut off by opening the switch B3, and at the same time, the power supply to the high frequency generator 17 is cut off by opening the switch B3.
The switches A2 to A4 are also opened, after which the temperature of the object to be heated decreases, and even if the relay B is reset, power is not supplied to the high frequency generator 17 again. Such an operation is suitable for reheating food that has been cooked once, and the operator can perform the desired heating operation without measuring the amount of food and calculating the corresponding heating time. I can do it. Next, the case of stewed dishes etc. mentioned above will be explained.

At this time, install the detector 8 and timer device 7.
When the boiling operation time is set to start after the heated object reaches a predetermined temperature, the high frequency generator 17 operates until the switch B3 is opened in the same way as described above. When the power supply is cut off, the timer motor 7d starts operating by closing the switch B2.
After that, when the temperature of the object to be heated decreases and the reset operation of relay B is performed and switch B3 is closed, the switches C2 and C3 of relay A are closed due to the operation of relay C, so switch A2 of relay A ~A4 is closed again, the power supply to the high frequency generator 17 is resumed, and the timer motor 7d is again closed.
The operation will also continue. Then, when the operation of relay B is repeated and heating cooking for the time set by the timer device 7 is completed, if relay B is operating to maintain switch B3 in the closed state at that point, it remains as it is. Heating continues, and when the temperature returns to a predetermined temperature, it is shut off. Thereafter, even if relay B performs a return operation, power supply to high frequency generator 17 is not restarted. In this way, by setting the detector 8 and the timer device 7, the operator can perform the desired stewed dish. Here, we have explained the simmering, that is, the warming operation, using stewed dishes as an example, but it is usually effective to carry out the heating operation along the temperature curve shown in Figure 3 for such cooking. Are known.

In the figure, the horizontal axis shows time S, and the vertical axis shows temperature T. The object to be heated is once heated to temperature Ta, and then kept warm between temperature Tb and temperature Tc, which are lower than temperature Ta. Become so. Note that this heat retention temperature is a fairly high value in the case of the above-mentioned stewed food, but in the case of the original heat retention, it is a relatively low temperature, and it is desirable to be able to control it. Fig. 4 shows that the temperature required for such heat retention can be arbitrarily set, and the temperature state of the heated object at each moment can be displayed on the meter 20, replacing the control circuit CON shown in Fig. 2. This is an example.

In FIG. 4, an AC power source E'' is connected to the other end of a capacitor 21 whose one end is grounded via a full-wave rectifier FD.
We are supplying electricity. The other end of the capacitor 21 is connected to the electromagnetic coil B of the relay B and one end of the resistor 22, and the other end of the coil B is connected to a PUT (programmable
It is connected to the gate terminal of a unijunction transistor (unijunction transistor) 23 and grounded via resistors 24 and 25. A Zener diode 26 is interposed between the power supply line 27 at the other end of the resistor 22 and ground, and a series circuit of a variable resistor 28 and a resistor 290 is also interposed between the power supply line 27 and ground. The midpoint of connection 29 is connected to the base terminal of transistor 30. The collector terminals of the transistors 30 and 31 are both directly connected to the power supply line 27, and the emitter terminals thereof are grounded via resistors 32 and 33, respectively, and a variable resistor 2' and a meter 20 are connected between the two emitter terminals. series circuit is connected. Temperature detector thermistor 8a'' and resistor 34
A series circuit consisting of a parallel circuit and a resistor 35 is also interposed between the power supply line 27 and ground, and its connection midpoint is connected to the base terminal of the transistor 31 and the comparison terminal of the comparison amplifier 36. The anode terminal of PUT23 is resistor 3
The power supply line 27 is connected to the power supply line 27 through a resistor 38, and its cathode terminal is grounded through a resistor 38 and connected to the base terminal of a transistor 40 through a variable resistor 39. The emitter terminal of the transistor 40 is grounded,
Its collector terminal is connected to the power supply line 27 via a potentiometer 41 and grounded via a resistor 42, and the setting terminal of the potentiometer 41 is interposed between the power supply line 27 and the ground via a potentiometer 43. Furthermore, the setting terminal of the potentiometer 43 is connected to the setting terminal of the comparator amplifier 36 and the midpoint between the resistors 24 and 25, and the output terminal of the comparator amplifier 36 is Connected to the gate terminal of PUT23.
The operation of the control circuit configured as described above will be explained with reference to the temperature curve diagram shown in FIG. In order to first set the desired temperature, variable resistors 28, 28'', 39 and potentiometers 41, 43, 44 are adjusted, respectively.
In this state, both the PUT 23 and the transistor 40 are cut off, so the thermistor 8a'' and the resistors 34 and 35
Decided with! The detected potential is detected by the potentiometer 41,
43, 44 and resistors 42, 24, 25, the output of the comparator amplifier 36 remains at a high level, and no current flows through the electromagnetic coil B', and the heating operation continues. When the temperature detected by the sensor 5 mister 8a'' reaches the temperature Ta in FIG. 3, the detected potential reaches the set potential and the output of the comparator amplifier 36 is inverted to a low level, thereby When a current flows through relay B and relay B enters the operating state (heating operation interrupted), PUT 23 and transistor 40 also become conductive, and transistor 40
into a conductive state set by variable resistor 39. According to such a series of operations, the voltage level of the setting terminal of the comparator amplifier 36 decreases, so even if the detected temperature falls below the temperature Ta, the above state (heating operation interrupted) is maintained, and only when the detected temperature falls to the temperature Tc. The output of comparator amplifier 36 returns to a high level, thereby interrupting the operation of relay B and restarting heating operation.

Then, in the next heating operation, the PUT 23 and the transistor 40 continue to be conductive, and the voltage level of the installed constant terminal of the comparison amplifier 36 is lower than the initial state, so the detected temperature is lower than the temperature Ta. It will be interrupted when Tb is reached. Thereafter, the heat retention heating operation between the temperature Tb and the temperature Tc is continued in the same manner. Incidentally, as the above-described heating control operation changes, the electric potential applied to the base terminal of the transistor 31 changes, so that the degree of conductivity of the transistor 31 also changes, and this change is displayed on the meter 20. .

As detailed above, in the control circuit of relay B shown in FIG. 4, temperatures Ta and Tc in FIG. 3 are set by potentiometers 41, 43, 44 and resistors 42, 44, 25,
The temperature n can be set by a variable resistor 39, and an effective heating operation can be performed for, for example, stewed dishes.

As described above, the present invention has realized a heating cooker that combines all the functions that conventional heating cookers had individually and has greatly improved usability, and has an extremely high industrial effect. It is a big thing.

[Brief explanation of the drawing]

Fig. 1 is an external view of a microwave oven showing an embodiment of the cooking device according to the present invention, Fig. 2 is its power supply circuit diagram, and Fig. 3 is a temperature curve diagram for explaining its preferred heat-retaining heating state. , FIG. 4 is a control circuit diagram for realizing this. In the figure, 2 is a heating chamber, 7 is a timer device, 8 is a temperature detector of a detection device, 17 is a high frequency generator which is a heating source, C,
Cl to C3 are relays of the heat retaining device, and Pl and P2 are changeover switches serving as switching means.

Claims (1)

[Scope of Claims] 1. A heating chamber for storing an object to be heated, a heating source for heating the object to be heated, a detection device for detecting that the object to be heated has reached an arbitrary set temperature, and a heat-retaining device for causing the heating source to perform a heat-retaining heating operation on the object to be heated after the detection device detects the set temperature; and a timer device for setting a heating operation time;
and a switching means for switching so that when the detection device is set, the timer device starts operation by the start of operation of the heat retention device, and when the detection device is not set, the timer device starts operation from the start of heating. A heating cooker.