JPS5918319A - Heat-cooking utensil - Google Patents

Abstract

PURPOSE:To improve the time efficiency of automatic cookig utensil equipped with a moisture and gas sensor and the like, by constituting such that a sensor element may be cleaned after a cooking start signal is inputted and the ventilation of heating compartment may be stopped until the sensor recovers its sensing capability. CONSTITUTION:An operation is started to clean a sensor simultaneously with a continuous heating of heat-cooking utensil after its cooking operation is started. The ventilation fan of heating compartment is kept inoperative until the sensor recovers its sensing capability. That is, the fan is rendered inoperative at the moment that a relative humidity inside the heating compartment is increased. This manner of operation can raise a humidity inside a room. Upon the sensor recovering its sensing capability, the fan is brought into operation again. All these controls are performed by microcomputer. This constitution can eliminate the risk of smoking and firing because the utensil emits no exhaust gas while the senser lacks its sensing capability, whereby permitting the utensil to heat a foodstuff continuously after started and to improve its time efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic heater, and more particularly to a heating cooker that automatically controls cooking using sensor means that is sensitive to water vapor or gas emitted from an object to be heated. It is.

Conventional Structure and Problems Conventionally, as shown in FIG. 1, in a microwave oven, a relative humidity detection sensor 12 that is sensitive to water vapor emitted from an object to be heated 2 is installed inside the heating chamber 1 or exhaust duct 11, so it is long. When used for a long time, droplets from the heated object 2 and volatile substances,
The sensor 12 becomes contaminated with oil smoke, etc., and its initial performance deteriorates during use.

There is a problem that sensitivity cannot be obtained. Therefore, a coil heater 14 is provided near the sensor element 13 as shown in FIG. 2, and the coil heater 14 is energized immediately after the start of cooking to heat the sensor element 13 to 4000C or more.
A cleaning method has been devised and implemented for microwave ovens and the like that burns away the adhering dirt and maintains good performance and sensitivity at all times. By the way, after the cleaning of the sensor 12 is completed and the power supply to the coil heater 14 is stopped, the sensor 12 cannot immediately obtain stable and good detection performance. The reason for this will be explained based on FIG. 3a.

FIG. 3a shows time on the horizontal axis and relative humidity on the vertical axis, and shows the change in relative humidity inside the exhaust duct 11 after heating starts. 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 sensor 12 is now cooled by the exhaust air and gradually returns to room temperature, so the relative humidity rises toward the 0 point. go. 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, and therefore decreases toward point D. Point D is the point where the increase in relative humidity due to water vapor emitted from the object to be heated 2 is greater than the decrease in relative humidity due to the rise in temperature of the exhaust air, and after this the amount of water vapor from the object to be heated 2 increases, so the relative humidity decreases. increases from point E 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 Fig. 3a that this relative humidity change amount ΔRH also occurs between point B and point 0 until the steady state is returned after cleaning is completed, but the change in relative humidity during this period is due to the change in the heated object. Since it is not caused by a large amount of steam emitted from 2, it cannot be used for heating p detection.

Therefore, it is necessary to wait for the time t0 for detection by the sensor 12.

By the way, if heating is started at high output from the start of heating, if the object to be heated 2 is small, the sensor 12
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. It is conceivable that when the relative humidity change amount ΔRH is reached, a situation will arise in which the relative humidity change amount ΔRH cannot be obtained. Therefore, as shown in FIG. 3, time t has elapsed since the start of cooking. Until then, the output will be zero. There is a way to make it higher output.

However, in the above method, no heating is actually performed from the start of heating to t, so the time required for heating is the entire time t. This has the disadvantage that it takes a lot more time and is less time efficient. Therefore, conventionally, the third
As shown in Figure C, at time t. Time t1 before reaching
There was a way to improve time efficiency by starting heating at high output (1 cm11). However, when determining t1ffi, the time (1
, -11) must be determined carefully to avoid producing large amounts of water vapor due to high-power heating between . Therefore, the current situation is that the time (1o-11) can only be taken about 1o seconds, and although the time efficiency has improved, there has been a problem that the time efficiency has not been significantly improved. Another conventional example will be shown. This is a method of heating at a low output PL for a predetermined time t' and then switching to a high output for heating.

There is also a conventional example shown in FIG. 3e. This is a method of heating in an intermittent operation for a predetermined time period of 11'', with T1 on and off for 12 hours, and after t1L/time, switching to continuous operation at high output.In this case, too, the above conventional example Similarly, low output PL, t1', tl'' mountains.

Each element of T2 must be determined with the object to be heated 2 in mind. 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. .

In addition, a conventional example in which the exhaust duct has been devised in order to eliminate the above-mentioned drawbacks will be explained with reference to FIGS. 4a and 4b.

In the figure a, reference numeral 1 denotes a heating chamber in which food 2 placed therein is heated with high frequency energy oscillated from a magnetron 3. Reference numeral 4 denotes a fan which cools three magnetrons and blows air through a blower duct 5, one blows air into the heating chamber 1 through a blower port 6, and is discharged through an exhaust port 10 into an exhaust duct 11. The other side passes through the ventilation duct 6 and heads toward the exhaust duct 11 . The exhaust duct 11 is partially divided into upper and lower parts by a partition plate 16. The 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. A valve 17 is constructed within the exhaust duct and is driven by a solenoid 18. The air blown to the sensor 12 by the valve 17 is switched between air from the ventilation duct and exhaust from the heating chamber.

With the above configuration, after the cleaning of the 7/12 is finished, until the sensor 12 becomes capable of sensing,
As shown in FIG. 4a, the valve 17 is not exposed to the steam 8 in the heating chamber 1, and thereafter, as shown in the same figure, the valve 17
As a result of this operation, the heating chamber 1 is exposed to the steam 8 in the heating chamber 1.

In other words, even if the amount of steam generated from the heated object 2 reaches its maximum before the sensor 12 can detect it, the sensor 12 will detect it as the amount of change in steam at least when the operation of the valve 1a is reversed. is possible. This made it possible to start the heating operation at the maximum output at the same time as cooking started, and to perform continuous heating.

However, even with the above configuration, there were still drawbacks that could not be resolved. It is a heated material with extremely low moisture content.
For example, in the heating of heat sinks, the moisture content of the object to be heated disappears only in the initial heating operation, and there are cases where almost no steam is generated. In such a case, no matter how devised the exhaust duct 11, etc., the sensor 1
2 could not be detected, which could lead to smoke and ignition, which could be said to be a serious drawback.

OBJECTS OF THE INVENTION It is an object of the present invention to eliminate the drawbacks of the conventional example as described above and to significantly improve time efficiency.

Structure of the Invention In order to achieve the above object, the heating cooker of the present invention includes 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 completely ventilating the heating chamber, an exhaust section communicating with the heating chamber, a sensor element provided in the exhaust section and sensitive to water vapor and gas generated within the heating chamber, and means for cleaning the sensor element. and a control unit for controlling the heating output of the heating means according to a signal from the sensor element, and cleaning the sensor element after an input signal for starting cooking is input, and The air blowing means for ventilating the heating chamber is at least temporarily stopped until the sensor means returns to a sensing state, thereby making it possible to automatically heat food with very low moisture content.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 5 to 7.

In FIG. 5, a heated object 2 generates steam 8 in a heating chamber 1 by high frequency waves generated from a magnetron 3. In FIG. After cooling the magnetron 3, the wind generated from the 77 chamber 4 passes through the ventilation duct 5 and is exhausted to the outside through the exhaust duct 11 while ventilating the inside of the heating chamber 1. The sensor 12 is located at the bottom of the exhaust duct 11, and a partition plate 19 is provided at the top of the exhaust duct 11.

Now, the relationship between the generation of steam by the heating operation, which is a feature of the present invention, and the fan rotation operation will be explained with reference to FIGS. 6 and 7.

FIG. 7a shows the heating operation, in which heating is performed continuously from the start of cooking. From time tF shown in the figure to 1, 1, the rotation of the fan 4 is stopped, and then the rotation is continued for a further time t. After that, the fan 4 starts rotating again.

These controls are performed by sending signals from a control section 20 including a microcomputer shown in FIG. 6 to all relays 21. Note that 22 represents a diode automaton 23 a capacitor, and 24 represents a high voltage transformer.

7, c, and d show the state of steam in each part by controlling the operation of the notebook fan 4.

First, this figure shows the transition of the amount of water vapor generated from the heated object 2 when heating the heated object 2 with extremely low moisture content, and as shown in the figure, the time t in the figure. Until then, the amount of steam generated is decreasing, until the point t above. After this point, steam generation completely disappears. Next, C in the same figure shows the relative humidity change inside the heating chamber 1, and as shown in the figure, it gradually increases at the same time as the heating starts, and the relative humidity increases at the time tF.
After a certain period of time has elapsed, that is, when the fan 4 is stopped, it rises rapidly. This is because the water vapor in the heating chamber 1 is diluted by the rotation of the fan 4, but the fan 4 suddenly stops and the water vapor in the heating chamber 1 is trapped inside the heating chamber 1. Furthermore, in FIG. C, when the fan starts rotating from tc, the water vapor that has remained until then escapes into the exhaust duct 11, so that the relative humidity rapidly decreases again.

Now, in the same manner, the change in relative humidity near the sensor 12 shown in d of the same figure will be explained. After the heating starts, the relative humidity in the heating chamber 1 increases for a while as the relative humidity changes, but the temperature changes from time tF to time t in the figure. It continues to descend. this is,
This is because since the fan 4 has stopped, air containing water vapor cannot circulate to the lower part of the exhaust duct 11. Furthermore, the figure t. When the temperature has completely passed, the water vapor accumulated in the heating chamber 1 starts to be exhausted all at once, and the relative humidity near the sensor 12 rapidly increases. This change in relative humidity ΔRH is large because it is due to the stored water vapor even if the heated object 2 contains very little water vapor, and is large enough for the sensor 12 to sense.

As is clear from the above explanation of the operation, even if the worst situation occurs in which the water vapor generated from the object to be heated 2 completely disappears by the time the sensor 12 becomes able to sense the 10 points, the fan 4
By stopping the water vapor and preventing it from escaping, it is stored and then exhausted all at once when the sensor 12 becomes able to detect it. This eliminates the problem of smoke and ignition occurring without the sensor 12 being able to detect it. Operations can now be performed continuously from the start, greatly improving efficiency.

Furthermore, if a partition plate 19 is provided at the top of the exhaust duct 11 like the exhaust duct 11 shown in FIG. 5, it is possible to prevent the water vapor in the heating chamber 1 described above from escaping by natural exhaust. , even more effective.

Further, if the sensor 12 is provided at the lower part of the exhaust duct 11, steam will reach the sensor 12 only when the fan 4 is rotated, which is effective.

In addition, even if the cooling air is stopped for a short time, Magnetro/3 has a large heat capacity, so the temperature will not rise suddenly, and there will be no problem in actual use.

Effects of the Invention As described above, according to the present invention, by retaining water vapor in the heating chamber at the initial stage of heating, it is possible to automatically heat and cook objects with low moisture content, further expanding the menu of automatic cooking. be.

[Brief explanation of drawings]

Fig. 1 is a side sectional view showing a conventional heating cooker, Fig. 2 is an external perspective view showing the sensor means of the same, Figs. 3 a-e are explanatory views of the operation of the same, Figs 4 a and b 5 is a side sectional view showing another conventional heating cooker, FIG. 5 is a side sectional view showing a heating cooker which is an embodiment of the present invention, FIG. 6 is the circuit diagram, and FIG.
Figures a to d are explanatory diagrams of the same operation. 1...Heating chamber, 2...Heated object, 3...
... Magnetron (heating means), 4...
・Fan (air blowing means), 5...Blower duct, 11
...Exhaust duct (exhaust part), 12...Sensor (sensor means), 13...Sensor element, 1
4... Coil heater (means for cleaning)
, 2o...Suppression club. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4 Figure 5

Claims (3)

[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 that is sensitive to water vapor and gas generated indoors and a means for cleaning the sensor element, and a control section that controls the heating output of the heating means based on a signal from the sensor element, After the input signal to start cooking is input, the sensor element is cleaned and the air blowing means for ventilating the heating chamber is temporarily stopped while the sensor element returns to a sensing state. A heating cooker. (2) The heating cooker according to claim 1, wherein the exhaust section is provided with an exhaust duct having a barrier section at the upper part that prevents natural exhaust, and a sensor element is provided below the exhaust duct. (3) The heating cooking device according to claim 1, wherein ventilation in the heating chamber is stopped only for a certain period of time immediately before the sensor means returns to a sensing state.