JPS58140521A - Heating cooker - Google Patents

Abstract

PURPOSE:To enhance time efficiency, by a method wherein a sensing element is cleaned before starting cooking to constantly obtain a stable detecting performance, and heating is conducted without waiting for a sensor to return to an operative condition. CONSTITUTION:The interior of a heating chamber 1 is ventilated by a blowing means 4, a relative temperature sensor 12 comprised of the sensing means 13 capable of responding to steam and gases generated in the chamber 1 and a coil heater for cleaning the element 13 is provided at an exhaust part 11, and the heating output of a magnetron 3 is controlled in accordance with a signal from the element 13. The sensing element 13 is cleaned in the period from the moment an input signal for starting cooking is inputted to the moment the sensor 12 returns to the operative condition, and the magnetron 3 is operated for a predetermined period of time. The heating output of the magnetron 3 is set at a low output or the operation of the magnetron is stopped immediately before the sensor 12 returns to the operative condition, thereby momentarily reducing the quantity of steam or the like generated from an object 2 to be cooked, and then the heating output is increased after the sensor 12 returns to the operative condition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic heating device, and more particularly to a heating cooking device that automatically controls cooking using sensor means that is sensitive to water vapor emitted from an object to be heated. As shown in FIG. 1, in the microwave oven, a relative humidity sensor 12 that is sensitive to water vapor emitted from the object to be heated 2 is installed in the heating chamber 1 or inside the exhaust duct 11, so if the oven is used for a long time, droplets emitted from the object to be heated 2 will be detected. and volatile substances,
The sensor 12 becomes contaminated with oil smoke, etc., and its initial performance deteriorates during use.

There is a problem that the sensitivity cannot be obtained.
As shown in FIG. 2, a coil heater 14 is provided near the sensor element 13, and immediately after the start of cooking, the coil heater 14 is energized to heat the sensor element 13 to 400°C or higher to burn off the attached dirt.・Cleaning methods that maintain good sensitivity at all times have been devised and implemented for microwave ovens, etc. By the way, after the cleaning of this sensor 12 is completed, stable and good detection performance cannot be obtained immediately. , the reason for this will be explained based on FIG. 3a.

Figure 3 shows time on the horizontal axis and relative humidity on the vertical axis, and represents the change in relative humidity inside the exhaust duct 11 after heating started. Heating starts from point A, but cleaning of the sensor 12 also starts at the same time, so the ambient temperature of the sensor 12 increases rapidly due to the heating of the coil heater 14, and the relative humidity gradually decreases toward point B. I'm going to go. Point B is the point at which the sensor 12 reaches a predetermined temperature and cleaning is completed. Although there is a slight overshoot because the coil heater 14 is no longer energized at point B, the 7/12 is now cooled by the exhaust air and gradually returns to room temperature, so the relative humidity rises toward the 0 point. I will do it. After reaching the 0 point and returning the sensor 12 to a steady state, the temperature of the exhaust air gradually increases due to the progress of heating. This is the point at which the increase in relative humidity due to water vapor from the heated object 6 exceeds the decrease in relative humidity due to the rise in temperature of the exhaust air 5. After this point, the amount of water vapor from the heated object 2 increases, so the relative humidity is at point E, It increases to point F.

Generally, the relative humidity change amount ΔRH is detected from point D and the output of the magnetron 3 is automatically controlled to control heating.

By the way, it is clear from Figure 3a that this relative humidity change △RH beam +7- also occurs between point B and point 0 until the Jungian cycle ends and returns to the steady state, but the change in relative humidity during this period is Since it is not caused by a large amount of steam emitted from the object to be heated 2, it cannot be used to detect heating. Therefore, the detection by the sensor 12 occurs at time t. However, if we were to start heating at high output from the start of heating, if the object to be heated 2 is small, it would be necessary to wait for a long time. The time it takes for t to return to a steady state, that is, time t. The relative humidity reaches 100 degrees by the time it reaches time t. When it reaches 6 -'-i', it is conceivable that the relative humidity change amount ΔRH cannot be obtained. Therefore, as shown in FIG. 3, there is a method of using zero output from the start of cooking until time t and then increasing the output to high output after t.

C.

However, in the above method, no heating is actually performed from the start of heating to 1o, so the time required for heating is t. There was a drawback that it took an extra 9 hours and the efficiency deteriorated. Therefore, conventionally, the third
As shown in Figure C, there is a means to improve time efficiency by starting heating at high output from time t1 before reaching time 1c (1, -11). However, when determining tl, the time (1C-
1) Care must be taken to ensure that a large amount of water vapor is not released due to high-power heating during (1).

Therefore, the current situation is that the time (1o-1,) is only about 10 seconds, and although the time efficiency has improved, there has been a problem that the time efficiency has not been significantly improved.

Furthermore, another conventional example is shown in FIG. 3d. This is a method of heating at a low output PL for a predetermined time t1/, and then switching to a high output for heating.

There is also a conventional example shown in FIG. 3e. This is a method in which heating is performed in an intermittent operation during a predetermined time t11, with the heating being turned on for the time T1 and turned off for 72 hours, and switching to continuous operation at high output after t1'. In this case as well, the elements of low output PL, t1', t1', T1°T2 must be determined for the object to be heated 2, as in the conventional example described above. In other words, the output is determined so that a large amount of steam does not come out from the object to be heated 2, but from the start of cooking. If the energy absorbed by the heated object 2 during this period exceeds a predetermined level, a large amount of water vapor will be generated, so the time efficiency can only be improved to the same extent as the conventional example shown in Fig. 3C. .

Therefore, the present invention aims to eliminate the above-mentioned drawbacks and significantly improve time efficiency.Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) In FIG. 1, reference numeral 1 denotes a heating chamber, which is heated by applied energy placed therein. , 4 is a fan motor which cools the magnetron 3 etc. and blows ventilation air 7 into the heating chamber through the air duct 6 and the air outlet 6. The exhaust air 9 containing water vapor 8 from the food 2 is The air is discharged through the exhaust port 10 into the exhaust duct 11. Reference numeral 12 is a relative humidity detection sensor that is sensitive to the relative humidity of the exhaust air 9. FIG. 2 shows an enlarged view of the relative humidity detection sensor (hereinafter simply referred to as sensor) 12. 13 is a sensor element, 14 is a coil heater provided near the periphery of the sensor element 13, and 15 is a support portion made of an upper 2-mick material.

Next, control of heating power, which is a feature of the present invention, will be explained based on FIGS. 4a and 4b.

In the figure, at the same time as the start of cooking, high output is applied for a predetermined time t2.
The time t for the relative humidity detection sensor 12 to return to a steady state after heating to Heating is stopped until t, and after reaching t, heating is resumed at high output.

That is, changes in the amount of water vapor in the heating chamber 1 are shown in FIG. Amount of water vapor at the start of R treatment! . is determined by the environment in which the microwave oven is placed. The amount of water vapor increases to T2 due to high output heating from the start of cooking to t2. However, from t2 the sensor 12 becomes capable of sensing t. Since the output is zero until then, no steam is generated during this time.
In addition, the steam in the heating chamber 1 is transferred to the heating chamber 1 by a fan motor 4.
Therefore, the amount of water vapor in the heating chamber 1 returns to the initial amount x0 of water vapor, so the heating from the start of cooking to t has no effect on the detection of relative humidity. Moreover, even if a large amount of water vapor is generated due to heating from the start of cooking to t2, it is possible to return to the initial environmental condition between t2 and t2, so that there is sufficient water vapor between the start of cooking and t2. Energy can be added to ゛. Therefore, the heating time is shortened by the time t2, and time efficiency is improved.

FIG. 6 shows an embodiment of such an electric circuit.

16 is a commercial power source, and 17 is a contact inserted into the main circuit, which applies electricity to the UNL and fan motor 4 at the start of cooking. 19 is a high voltage transformer, 20 is a high voltage 1° capacitor, and 21 is a stack diode, which serves as an anode power supply to the magnetron 3. 23 is the contact point of the high voltage reed relay, which turns on the anode voltage to the magnetron 3.
It's off. The coil 22 is controlled by a microcomputer control section 18.

Further, FIG. 6 shows another embodiment of the above electric circuit. 26
is a relay, 24 is its coil, and control section 1
8. Further, the relay 26 and its coil 24 can be implemented with a triac.

With the circuit configurations shown in FIGS. 4 and 6 above, after the start of cooking, the high voltage reed relay 23 in FIG. 4 and the relay 26 in FIG. 6 are turned on until t2 to oscillate the magnetron 3, and then turned off after t2. The magnetron 3 is turned on again after tC to cause the magnetron 3 to oscillate and heat at a high output.

In the circuit shown in FIG. 5, the relay 26 is located on the low voltage side next to the high voltage transformer 19, so it does not require a special race inch and can be said to be economical.

Page 11 (Second Embodiment) Another embodiment is shown in FIG. 4C. In this embodiment, heating is performed at high output until a predetermined time t2' at the same time as cooking starts, and then at low output PL until time t when the sensor 12 returns to a steady state.
Heating is performed with ', and after 1C, switch to high output and heat.

Since the amount of water vapor generated from the object to be heated 2 is determined by the amount of heat applied to the object to be heated 2, if the low output PL' is set to such an output that almost no water vapor is generated, the amount of water vapor generated from the object to be heated 2 will be the same as that shown in Figure 4 above. As described in the embodiment, the environmental conditions can be returned to the same conditions as immediately after the start of cooking at 10 o'clock.

An electric circuit for implementing this embodiment is shown in FIG.

28 is the contact point of the power switching relay, and when it is on, the first high-voltage capacitor 2o and the second capacitor 26 are connected in parallel, so the combined capacitance is large. The output is low at times.

27 is a coil of a power relay switching relay, which is driven by a signal from the control section 18.

(Third Example) At the same time, it was heated at high output until a predetermined period of time, and then heated intermittently until 70 days, with OFF for 13 hours and ON for 74 hours. After that, the output is switched to high output. tli et al.
. The output is substantially low until time T1. In determining T2, it is necessary to make it the same as the low output PL' of the embodiment shown in FIG. 4C described above. The electric circuit for realizing this embodiment may be that shown in FIGS. 6 and 6 described above.

As is clear from the first to third embodiments described above, from t2' to to and from t2' to t. By heating at substantially low output during this period, cooking time efficiency can be further improved.

(Fourth Embodiment) Still another embodiment of the present invention is shown in FIGS. 8a and 8b. In FIG. Heat. Reference numeral 4 denotes an unmotor which cools the magnet 13 and passes through the air duct 6. One side blows air through the air outlet 6 into the heating chamber 1, and the other side blows air into the heating chamber 1 through the outlet 1o and is discharged into the exhaust duct 11. . The other side passes through the ventilation duct 6 and goes toward the exhaust duct 11 . The exhaust duct 11 is partially divided into upper and lower parts by a partition plate 29. sensor 12
is attached to the upper part of the exhaust duct 11 which is partially divided into two parts. The exhaust duct 11 and the ventilation duct are in communication. Inside the exhaust duct, there is a valve 3o and a solenoid 31.
Driven by. The air blown to the sensor 12 by the valve 3o is switched between air from the ventilation duct and exhaust from the heating chamber.

In the above configuration, the following operations are performed.

At the start of cooking, the valve 3o is placed in the position shown in FIG.
After the sensor 12 returns to the sensing state, the valve 3o moves to the position shown in FIG. 8, and only the exhaust air from the heating chamber is blown to the sensor 12. At this time, high frequency energy is applied as shown in Figure 9a, and the situation of steam generation is shown in Figure 9b1.
The change in the relative humidity of the 14th floor near the cell/seat 12 is shown in Figure 9C.The amount of water vapor increases from Io to Io due to heating from the start of cooking to 70, as shown in Figure 9C. The initial relative humidity RHO shifts to a lower humidity side by cleaning the sensor 12, but the sensor 12 is cooled by the air blown from the air duct 6, and the temperature rises to t.
Sometimes the relative humidity returns to almost the initial relative humidity RH□. Thereafter, the valve 3o is switched, and the exhaust air from the heating chamber 1 is sent to the sensor 12. Therefore, water vapor was generated at 70 o'clock! . increases to relative humidity RH(2. If 4(RH
c-RHo) reaches a predetermined relative humidity change amount ΔRH, it is determined that the object to be heated 2 has reached a certain cooking state, and the heating is automatically controlled.

If ΔRH has not been reached, as shown in Figure 9C,
As the temperature of the exhaust air increases, the relative humidity gradually decreases. The relative humidity RHmin at the point where the rise in relative humidity due to water vapor exceeds the rise in temperature is taken as the lowest value, and then the relative humidity 111 (increases due to the rapid increase in water vapor, and the weight increase of △RH from RHmin Detects and automatically controls heating.

In this way, by exposing the sensor 12 to the exhaust air after it returns to a sensing state, and until then exposing it to an atmosphere that is almost the same as the initial atmosphere, even if a large amount of water vapor is generated before /S 12 always detects the initial environment at time t0 and then detects the exhaust air, so 1. Previous water vapor evolution can also be detected. Furthermore, even if a large amount of water vapor is generated after t0, the relative humidity can be detected in the same manner as in the first embodiment described above.With this configuration, the detection of relative humidity can be performed for 70 minutes from the start of cooking, and after that. As described above, according to the present invention, the following effects can be obtained.

(1) According to the present invention, since the sensor element is cleaned at the start of cooking, stable detection performance is always obtained, and since heating is performed without waiting until the sensor returns to a sensing state, it is time efficient.

(2) Immediately before the sensor returns to a sensing state, the environmental conditions are always almost the same as those immediately after the start of cooking. Furthermore, since a large amount of energy can be applied before the sensor returns to a sensing state, the cooking time can be significantly shortened.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a heating cooker according to an embodiment of the present invention, Fig. 2 is an enlarged external perspective view of the sensor section of the same, and Figs. 3 a-e are relative humidity of a conventional heating cooker. FIG. 4a is a characteristic diagram showing changes in the amount of water vapor in the heating cooker according to the first embodiment of the present invention, and FIG.
Figure 4C is a characteristic diagram showing the heating pattern of the same device, Figure 4C is a characteristic diagram showing the heating pattern in the second embodiment of the present invention,
FIG. 4d is a characteristic diagram showing a heating pattern in the third embodiment of the present invention, FIG. 6 is an electric circuit diagram in the first embodiment of the present invention, and FIG. 6 is another electric circuit in the first embodiment. Fig. 7 is an electric circuit diagram in the second embodiment, Fig. 8a
,b is a side sectional view of a heating cooker according to a fourth embodiment of the present invention, and FIG. 17 Pemi b and c are characteristic diagrams showing changes in the heating pattern, water vapor amount, and relative humidity of the same vessel. 1... Heating chamber, 2... Heated object, 3.
... Magnetron (heating means), 4...
...7 Unmotor (air exhaust means), 11...Exhaust duct (exhaust part), 12...Medium/relative humidity detection sensor (
sensor means), 13...S/S element, 14...
... Coil heater, 18 ... Control section (control section). Name of agent: Patent Attorney Toshio Tsuchinakao LiIFIIJ 113 Figure 684 Figure @ 5 Figure 7 Figure 8 Figure 9

Claims (4)

[Claims] (1) A heating chamber for storing an object to be heated, a means for heating the inside of the heating chamber, an air blowing means for ventilating the inside of the heating chamber, an exhaust section communicating with the inside of the heating chamber, and a heating section provided in the exhaust section for heating the inside of the heating chamber. A sensor means having a sensor element sensitive to water vapor and gas generated indoors and a means for cleaning/cleaning the sensor element, and a control device controlling the heating output of the heating means based on a signal from the sensor element. cleaning the heating element within the time required from inputting an input signal to start cooking until the heating means returns to a sensing state and operating the heating means for a predetermined period of time; Immediately before the sensor means returns to a sensing state, the heating output of the heating means is reduced or stopped to determine the amount of water vapor or gas generated from the object to be heated. 2. A heating cooker configured to temporarily reduce the heating output and then increase the heating output after the heating output returns to a detectable state. (2) The heating output is set to high for a predetermined period of time within the time required for the sensor means to return to a sensing state after the input signal to start cooking is input, and after the predetermined period of time has elapsed, The heating cooker according to claim 1, wherein the output is zero until the sensing means returns to a sensing state. (3) The heating output is set to high for a predetermined period of time within the time required for the control means to return to a sensing state after the input signal for starting cooking is input, and after the predetermined period of time has elapsed, The heating cooker according to claim 1, wherein the output is substantially low until the sensor means returns to a sensing state. (4) During the time required for the sensor means to return to a sensing state after the input signal to start cooking is input, the supply of exhaust air to the detection section of the sensor means is stopped and the heating is continued. 3. The cooking device according to claim 1, wherein the exhaust air is supplied to a detection section of the sensor means after the sensor means returns to a sensing state.