JPH02219913A - Heating and cooking device - Google Patents

Abstract

PURPOSE:To perform thawing with high efficiency by a method wherein a planelike far infrared ray radiation heater the surface of which is formed of a material emitting electromagnetic waves of a specified wavelength or above is provided to a cooking chamber in which food is contained, and the drive of the heater is controlled so that, during thawing of frozen food, the temperature of a heater surface is adjusted to be in a specified temperature range. CONSTITUTION:Heater surfaces 7' and 8' radiating an electromagnetic wave of a wavelength of 2mum or more with a high efficiency is formed of radiation panels 7a and 8a, respectively. A controlling circuit to control energization to heaters 7 and 8 so that the temperatures of the heater surfaces 7' and 8' are detected by a thermistor and the detecting temperature is adjusted to 180-250 deg.C when thawing cooking is selected is incorporated in a space behind a panel 11. Electromagnetic waves are radiated with high efficiency, and even when a part of a frozen food is thawed and a moisture content is generated, the moisture content and unthawed parts are heated without the occurrence of nonuniformity, and thawing is progressed rapidly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooking device for cooking food, and particularly to one that can enjoy the function of defrosting frozen food.

[Conventional technology]

In recent years, with the rapid spread of frozen foods, the proportion of thawing cooking in cooking operations has increased. Conventionally, heating cooking devices equipped with the function of thawing frozen foods have been equipped with microwave heating means as a heating source. They used a microwave which was hot.

[Problem to be solved by the invention]

Conventional addition! P: 1 for cooking equipment. During thawing, if a portion of the frozen food is thawed by microwave heating and moisture is generated, the heating is concentrated on this portion, causing a problem that the unthawed portion is not heated.

That is, in general, microwave absorption and accompanying heating are expressed by the following equation.

In addition, Q is the heat generated per unit volume per hour i (cal)
.

f is the microwave frequency () Iz, l (e.g. 2.45
x 10'Hz).

V is the magnitude of the microwave electric field (V/m), ε is the dielectric constant of the heated object, and -δ is the dielectric loss angle.

As shown in this equation, microwave absorption and the accompanying heating are proportional to the loss coefficients ε and -δ of the heated object, and when there are both large and small loss coefficients, , the heating rate of each will be different.

Here, the loss coefficient of ice (-13℃) is 28X10-',
Water loss factor is 123000 x 10” at 25°C,
40200XIF' at 55℃, and the loss coefficients of ice and water are significantly different. Therefore, when a portion of frozen food is thawed by microwave heating and generates moisture, the heating concentrates on this moisture, causing the The thawing part will not be heated.

For this reason, in conventional heating cooking devices, in order to alleviate such uneven heating during thawing, the microwave oscillator is operated intermittently to alternately repeat microwave oscillations and pauses.
In addition to suppressing the excessive concentration of heating on the parts that have thawed into water, the method used is to gradually change the state of ice into water through heat exchange with the heated water.

However, this method has the disadvantage that it takes a long time to decompress and it is very difficult to decompress completely.

Furthermore, this type of heating cooking device requires a high frequency power source such as a magnetron as a microwave oscillator, which increases equipment costs and requires a radio wave/L/structure in the door etc. and a safety device when opening the door. The drawback is that it is necessary and structurally complex.

The present invention has been made in consideration of the above-mentioned problems of the conventional technology, and its purpose is to provide a simple and inexpensive cooking device that can thaw and cook frozen foods with high efficiency. This is what I am trying to do.

[Failure to solve the problem]

In order to achieve the above object, in the heating cooking apparatus of the present invention, the surface of the two heaters is 2μ in the cooking chamber where the poor items are stored.
A planar far-infrared radiation heater made of a material that emits electromagnetic waves with a wavelength of m or more with high efficiency is provided, and the heater surface is heated to 180 to 250° C. when frozen food is thawed. The invention is characterized in that it includes a control means for controlling the driving of the motor.

[For production]

Figures 3 and 4 show the absorption spectra of water and ice (-10°C), respectively.
, it is clear that they have the same peak for electromagnetic waves around 15 μm.

This means that there is little non-uniformity in the heating of water and ice even if some of it becomes water due to thawing.

Part 2 of FIG. 5 shows that it is possible to radiate an electromagnetic wave having a wavelength around 6 μm at which the base density is maximum according to Wien's displacement law.

Therefore, by controlling the temperature of the far-infrared radiation heater surface of the far-infrared radiation heater installed in the cooking room at 180 to 250°C, electromagnetic waves with a wavelength of around 6 μm can be radiated from the heater surface with extremely high efficiency. As a result of being efficiently absorbed by water and ice, even if water is generated by thawing the frozen food, this water and the unthawed portion are heated without any unevenness, and thawing is completed in a short time and reliably. I will do it.

Here, if the heater surface temperature is controlled to 700°C, electromagnetic waves with a wavelength of around 8 μm can be emitted, and water and ice can be heated without being selective, but in this case, as is clear from Figure 4, Since ice does not have an absorption spectrum for electromagnetic waves (infrared rays) with a wavelength of less than 3 μm, there is a disadvantage that a lot of thermal energy is wasted. However, in this case,
Since the absolute amount of thermal energy is large, it can be used when rapid thawing is required.

Furthermore, if an attempt is made to radiate electromagnetic waves with a wavelength of around 15 μm, which has the same high absorption in water and ice, the heater surface must be made much taller than normal crystal, which is impractical.

In addition, in heating cooking other than thawing, the effect of irradiation with far infrared rays is widely known from experience.

〔Example〕

An example will be explained using FIG. 1 and FIG. 2.

(1) is the main body of the heating cooking device, and (2) is a cooking chamber formed within the main body (1), the front opening of which is openable and closable by a door (3). (4) is a 1.1/A tray that is stored in the central part of the cooking chamber (2) in a vertically adjustable manner, on which the grill (5) is supported, on which the food to be heated (6) is placed. is placed.

(7) & (8) are planar far-infrared radiation upper and lower heaters installed on the ceiling and bottom of the cooking chamber (2), respectively. The radiating plates (7a) and (8a) made of ceramics mainly made of zirconia, magnesia, alumina, etc. are attached to the top and bottom plates of the cooking chamber (2) through the radiating plates (7a) and (8a), respectively. (8a) forms a heater surface (d, (8)' that emits iii:(d waves with high efficiency) each having a wavelength of 2 μm or more.

Here, the lower heater (8) functions to maintain the internal temperature at a predetermined temperature during the 5-thaw cooking process.

αυ is an operation panel placed on the front right side of the main body (1); 1. The cooking selection switch (6) is equipped with several cooking selection switches (6) that are suppressed depending on the food to be prepared, a mechanical timer switch Q3 for setting cooking time, etc., and is compatible with thawing and cooking of frozen foods. Defrost by suppressing and setting the time with timer switch Q4, 1il
I-filling is executed.

In the space behind this panel 0p, when thawing cooking is selected, a heater (7), which detects the temperature of the heater surface (7/, A control circuit for controlling energization to (8) is built-in.

When defrosting and cooking, the frozen food is placed on the grill (5), the door (3) is closed, and after selecting defrost cooking with the selection switch αa, the timer is set for the predetermined cooking time. When set with switch α, thawing cooking starts.

Therefore, by driving and controlling both heaters (7) and (8) by the control circuit, each heater surface (7)
)'.

(Since the temperature of the heater is controlled at 180 to 250 degrees Celsius, electromagnetic waves with a wavelength around 180 μm are radiated from the surface of this heater (7) /, <8) / with high efficiency, causing some of the frozen food to thaw. Even if moisture is produced during the process, this moisture and the unfrozen portion are heated without causing non-uniformity, and thawing proceeds rapidly.

In addition, the moisture generated by thawing is collected in the tray (4).

In addition, cooking of food in one's own room can be achieved by selectively operating the corresponding cooking selection switch @.

Heater (7) so that the quality of cooking can be adjusted according to the content of cooking.
(8) is driven and controlled.

Note that a microcomputer may be used as a control means for controlling the drive of the heaters (7) and (8), and various switches on the operation panel Qυ may be replaced with touch type switches.

〔Effect of the invention〕

Since the present invention is configured as described above in Section 5, it produces the effects described in Section 7 below.

The temperature of the far-infrared radiant heater surface installed in the cooking room is controlled at 180 to 250 degrees Celsius during thawing, which increases the electromagnetic waves that can heat water and ice from the heater surface without causing unevenness. It can radiate energy efficiently and thaw frozen foods efficiently.It eliminates the need for intermittent operation unlike microwave heating that has selective heating properties, and enables continuous heating, significantly reducing thawing time. Can be shortened,
In addition, it is possible to provide an inexpensive and simple heating cooking device with a thawing cooking function without requiring a high frequency power source or a radio wave seal or other complicated materials as in the case of microwave heating.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the heating cooking apparatus according to the present invention, in which FIG. 1 is a cutaway front view, and FIG. 2 is a perspective view.
4 and 4 are characteristic diagrams showing the absorption spectra of water and ice, respectively, and FIG. 5 is a characteristic diagram showing the subspectral radiant energy curve of a black body. (2)...Cooking chamber, (7), (8)...Far-infrared radiation upper and lower heaters 2 (7)/, (8)/.
heater surface.

Claims (1)

[Claims] (1) The heater surface is 2 μm in the cooking chamber where food is stored.
A planar far-infrared radiating heater made of a material that emits electromagnetic waves of the above wavelengths with high efficiency is provided, and the drive of the heater is controlled so that the temperature of the heater surface is 180 to 250 degrees Celsius during thawing of frozen food. A heating cooking device characterized by comprising a control means for controlling.