JPS6026321Y2 - Cooking device - Google Patents

Description

[Detailed description of the invention] This invention relates to cooking appliances such as electronic ovens, electric ovens, gas ovens, etc., and particularly to cooking time control.The purpose of this invention is to detect the cooking state of food and heat it appropriately. It is in.

Generally, the heating time of food is determined by various quantities such as the initial temperature, weight, specific heat, and absorbed energy of the food.

However, in conventional cooking devices such as microwave ovens, the heating time is determined based on the type and amount of food to be heated.

Therefore, in this case, among the various quantities that contribute to determining the heating time, the specific heat of the food, the initial temperature of the food, and the final temperature of the food are not particularly taken into account, and cooking errors may occur if the heating time is set for this purpose. The reality is that

Therefore, in order to solve the problems of the conventional heating time setting, the present invention provides a humidity sensor and a heating element that refreshes the humidity sensor, and energizes the heating means after refreshing the humidity sensor with this heating element. It is.

That is, it is equipped with a humidity sensor that measures (senses) the humidity increased by water vapor generated from the food being heated, and a heating element that increases the temperature near the humidity sensor, and the heating element is energized before heating the food. This evaporates dust and moisture adhering to a portion of the humidity sensor.

Thereafter, the current flowing to the heating element is reduced, thereby maintaining the relative humidity near the humidity sensor slightly lower than the humidity in the heating chamber or kitchen at that time.

Or, the same effect can be achieved by applying cooling air from a magnetron to the humidity sensor (the humidity will be slightly lower than that in the heating room or kitchen)
There is.

After that, the heating means starts heating the food,
This measures the water vapor generated from the food, and when the humidity rises to a predetermined value, the heating is stopped.

An embodiment in which the present invention is applied to a microwave oven will be described below with reference to the accompanying drawings.

In Figure 1, 1 is the microwave oven body, 2 is the food installed in heating chamber A, 3 is a blow-in fan, 4 is a magnetron, and 5 is a humidity sensor, which is installed at the exhaust port A' of heating chamber A. ing.

Further, 6 is a heating element that heats the atmosphere near the humidity sensor 5, 7 is a humidity increasing type, 8 is a cooking state detection circuit, and 9 is a control circuit for the heating element 6.

In this configuration, food 2 is placed in heating chamber A and the cooking button (
(not shown).

Then, the control circuit 9 of the heating element 6 is activated, whereby the heating element 6 generates heat to blow off the dust attached to the humidity sensor 5 and water vapor (absorbed moisture) from the previous use, thereby refreshing the humidity sensor 5.

When this has been completed (in this embodiment, the surface of the humidity sensor 5 has reached 400 degrees Celsius or higher), a small current is applied to the heating element under the control of the control circuit 9 to lower the relative humidity by an amount calculated from the relative humidity at that time. 6.

Thereafter, when the humidity sensor 5 cools down from the high temperature caused by the above-mentioned refreshing, the magnetron 4 is energized to start cooking.

Then, the food 2 emits steam, the humidity sensor 5 senses the relative humidity at that time, the cooking state sensing circuit 8 detects the relative humidity difference from the time when cooking started, and this controls the radio wave oscillation of the magnetron 4. be.

FIG. 2 is a graph of the relative humidity detected by the humidity sensor 5 in the state described in FIG. 1.

~T5 represents time, and Ho and H5 represent humidity at each time.

T the time you just pressed the cooking button and the humidity at that time.

, HO, then T1. Hl
The relative humidity is at its lowest.

Then, when the current to the heating element 6 is switched to a minute current, the humidity sensor 5 is cooled and the relative humidity increases.

Note that the humidity of the magnetron 4 in a state where the cooling air temperature and the atmospheric temperature of the humidity sensor 5 are balanced is T2.
．． It becomes H2.

At T2, if the magnetron 4 is energized and heating continues, the amount of water vapor generated from the food 2 will be greater than the amount of water vapor generated by the magnetron 4.
The cooling air temperature becomes higher, and the relative humidity gradually decreases accordingly.

The point at which the amount of water vapor generated from food 2 increases and the humidity begins to rise is T3. At H3, the cooking state sensing circuit 8 of FIG. 1 stores the relative humidity at this point (note that the cooking state sensing circuit 8 does not store the humidity up to T2).

) Then, at the time T4 when a change in relative humidity greater than the preset relative humidity is detected? Either finish cooking at H4 (stop magnetron 4) or, depending on the content of cooking, further heat for a time k (T4 - T2), which is the time from T2 to T multiplied by a constant (depending on the content of cooking). Finish cooking.

In this embodiment, the operations described above are performed.

Here, the relative humidity T1. When the cooking state sensing circuit 8 stores H□, the time T2. when the heating element 6 returns to near normal temperature. Since the relative humidity at H2 changes beyond the preset relative humidity (H4-H3), the magnetron 4 may stop a short time after the start of cooking.

Therefore, in order to prevent this, in this embodiment, the time T2 until this refresh is completed is set by the cooking state sensing circuit 8.
It has a built-in delay circuit (usually within a few minutes) to prevent it from operating.

In addition, in this embodiment, the magnetron 4 is not operated when necessary for refreshing, but is operated after several minutes (T2), for example, to start cooking, so that malfunctions due to refreshment are avoided as described above. It does not occur.

Furthermore, the completion of refreshing is a recovery time that does not cause malfunctions, and there is no need for the temperature to completely return to room temperature.

That is, it is sufficient to complete the refreshment before steam is generated from the food to be cooked, and the magnetron operation may be performed before the temperature completely returns to room temperature.

It goes without saying that even during refreshment, the same effect can be achieved if the circuit and configuration are such that it emits low-power high-frequency waves and completes refreshment before steam comes out from the food being cooked.

As described above, according to the present invention, since cooking starts after refreshing, heating time control is not affected by changes in relative humidity caused by refreshing, and therefore the initial temperature, weight, and Accurate time control is performed in accordance with specific heat, absorbed energy, etc., and as a result, cooking mistakes are avoided.

[Brief explanation of drawings]

FIG. 1 shows the constituent countries of a cooking appliance according to an embodiment of the present invention, and FIG. 2 shows a characteristic diagram of the cooking appliance. A... Heating chamber, 2... Food, 4...
... Magnetron (heating means), 5 ... Humidity sensor, 6 ... Heating element.

Claims (1)

[Scope of utility model registration request] (1) A heating device that heats food, a humidity sensor that detects humidity that changes when the food is heated by the heating device, and a heating element that is provided to refresh the humidity sensor, and A cooker configured to start heating food as early as the time corresponding to the output before the sensor refresh is completed. (2.) The cooking appliance according to claim 1, which is configured to perform heating with low output while the humidity sensor is being refreshed.