JPS6029524A - Heating cooker - Google Patents

Abstract

PURPOSE:To facilitate the cleaning operation of a heating chamber after cooking by a structure wherein cracking catalyst layer is formed onto the wall surface of the heating chamber. CONSTITUTION:The cleaning of a heating chamber is facilitated by preventing objects flown from food to be heated from putting on by baking while realizing the evenness of smooth surface and strength same as those of normal enamel layer through the formation of cracking catalyst layer 18 onto the inner wall surface of the heating chamber. In order to form cracking catalyst layer 18, firstly, for example, clean substrate metal 16 by degreasing and dry it by air drying. After that, the mixture of cracking catalyst consisting of powder such as Al2O3, SiO2, MgO or the like and powder of conposite compound such as zeolite, mullite, cordierite or the like, frits consisting of B2O3, Na2O, K2O, SiO2, TiO2, LiO2 or the like and slip consisting of mill agent, water or the like is coated onto the substrate metal by spraying and baked at 700 deg.C for 3-7min.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heating cooker in which a cracking catalyst layer is completely formed on the wall surface of the heating chamber, thereby making it easy to clean the inside of the heating chamber after cooking.

In recent years, heating cookers called self-cleaning open cookers have been steadily gaining popularity as their convenience has been recognized.

This type of self-cleaning type cooker always has an oxidation catalyst layer on the wall surface of the heating chamber, which oxidizes heating products such as oil scattered from the heated food during cooking and turns it into carbon dioxide gas and water. It is something.

The oxidation catalyst layer needs to be porous with a fine pore structure in order to exhibit its full catalytic performance. This is because the larger the specific surface area of the catalyst, the better in promoting the chemical reaction of the catalyst, oil, and oxygen on the catalyst surface at high temperatures.

However, this porous catalyst layer does not allow the supply of air (oxygen) necessary for oil combustion when a large amount of oil is splashed all at once and the catalyst surface is completely covered with oil. Since the oxidation reaction is cut off, the oxidation reaction no longer progresses, and the oxidation reaction progresses exclusively to tar, which sticks to the catalyst surface. This tarred substance is generated not only on the surface of the catalyst layer but also on the surface of the internal micropores, so even if the above-mentioned tarred substance is scraped off from the surface of the catalyst layer, the activity of the catalyst will not be restored. . Also from heated foods.

During cooking, proteins, carbohydrates, blood, seasonings, etc. are scattered outside of the oil, but these are not oxidized and purified during cooking. These are accumulated in the micropores of the catalyst layer, and together with the tarred oil mentioned above, they gradually deteriorate the activity of the catalyst. This is a self-cleaning cooker that fully utilizes the porous oxidation catalyst layer.

With its use, the lifespan of the h-shifted catalyst will be shortened, and it must be considered that the lifespan of the catalyst is considerably shorter than that of the cooking device itself.

Let's consider all the firing conditions for the porous oxidation catalyst layer.

The oxidation catalyst layer is usually fired by coating a mixture of oxidation catalyst and binder on a so-called enameled steel plate that has been enameled in advance, or by firing it directly onto a galvanized or aluminized steel plate. . If we look at the case where the entire catalyst layer is formed on an enameled steel plate, the base is enamel and the oxidation catalyst layer is properly bonded and the adhesion is excellent. When this is achieved, the catalytic components are excessively combined with the glassy material, thus forcing a reduction in the porosity of the catalytic layer. However, if you give priority to porosity.

It is inevitable that the adhesion between the base layer and the catalyst layer will deteriorate. Direct catalyst on galvanized steel plate or aluminized steel plate 1-
The situation is exactly the same when forming a party.

One possible solution to this situation is to use it as a binder for low softening point glass frit, thereby achieving excellent porosity and adhesion despite firing at an unprecedentedly low temperature. However, in order to lower the melting point of the binder, it is necessary to contain a large amount of an alkali component.If a binder containing a large amount of an alkali component continues to absorb moisture or soak in water after firing, Significant elution of alkaline components occurs, which eventually not only makes the film of the catalyst layer brittle, but also weakens the bond between the base layer and the catalyst layer, making it easy for the catalyst layer to peel off. See all recent cooking appliances. In addition to open heating, there are a growing number of products that have all the functions of steam heating, so binders containing a large amount of alkaline components such as those mentioned above cannot be used in cookers that have a steam heating function. High porosity is essential for the catalyst layer that exhibits full oxidation catalytic performance.

In addition, because of this, catalyst performance tends to deteriorate quickly due to the formation of tar due to particles scattered from foods. Yet again. Because it is porous, it is brittle and has low strength. Also, from the viewpoint of elution of alkaline components in the binder.

There is an aspect that makes it difficult to use the steam heating function in a heating cooker that is biased toward the metal.

The present invention was inspired by the above-mentioned problems of porous oxidation catalysts. Composed of a cracking catalyst that does not require porosity, it achieves the same level of smoothness and strength as a regular enamel layer, while completely preventing the burning of scattered particles from the heated food, making it possible to completely clean the heating chamber. It was made easy.

Since the cracking catalyst is not an oxidation catalyst, there will be no disappearance of scattered particles from the oxidation catalyst layer (disappearance due to oxidation reaction), but since persistent burning of the scattered particles will not occur, the labor required to clean the heating chamber will be significantly reduced. This is something that will be reduced.

The present invention will be explained in detail below.

FIG. 1 shows an electric open circuit equipped with loop-shaped sheathed heaters on each of the ceiling wall side and the bottom wall side in a heating chamber. In this first prisoner.

Reference numeral 1 denotes an electric open body, and 2 denotes a heating chamber formed inside this body 1. 3 is a heater provided on the ceiling wall 4 P side of the heating chamber 2, and 5 is a heater provided on the bottom wall 6 side. 7.8ij is the heater holder attached to the ceiling wall 4 and bottom wall 6 mentioned above. Reference numeral 9 indicates the inner wall of the heating chamber, 10 indicates the left side wall of the heating chamber, and 11 indicates the right side wall of the heating chamber. In addition, inside the heating chamber 2, there are stored a tray rack, a grilling plate supported by the tray tray, and a food to be heated placed on the grilling tray, but these are completely omitted in Fig. 1. ing. This door opens and closes the 12 heating chambers 2. 13 is a control panel, 14 is a dial for a heating time control device, and 15 is a dial for a temperature adjustment device. The inner wall surface of this electrically open heating chamber 2, that is, the ceiling wall 4. Bottom wall6. Back wall 9. A cranking catalyst layer is completely formed on the left side wall 10 and right side wall 11. FIG. 2 shows a cross section of the heating chamber wall on which the cranking catalyst layer has been formed. 16 is the base metal plate having the aluminum plating layer 171i, and 18 is the racking contact fired on the aluminum plating layer 17. -8i bonding layer provides excellent adhesion against stress such as heat shot and impact.

Now, what about the process of forming the cranking catalyst layer 18? Let me tell you. First, the base metal 16 is degreased, cleaned, and air-dried. AI! on the base metal 16 thus obtained! , 203, 8
A cranking catalyst composed of powders such as i02, MfO, and powders of composite compounds such as zeolite, mullite, and cordierite, and B2O3, Na2O, and K2O.

Frit made of 5i02, TiO2, LiO2, etc.

Spray the entire mixture with a slip consisting of a milling agent and water. The composition ratio of the cranking catalyst and the frit in this spray-applied mixture is adjusted so that the cracking catalyst component is 130 wt%. For the frit, the alkaline content such as Na2O and K20 is 20wt%.
Adjust so that When the frit components are adjusted in this way, the melting point is set at 600-650°C. Firing is carried out at a temperature of 700°C, which is slightly below the first transformation point of Fe in the metallographic structure of the steel sheet used as the base metal, making it possible to produce enamel with a low alkali content. It is in a molten state and the adhesion to the base metal is increased to the same level as ordinary enamel.
This temperature is necessary to achieve the same level of surface smoothness as ordinary enamel. The amount of spray-applied mixture is adjusted so that the layer thickness after firing is approximately 80 μm. A cranking catalyst is sufficient as long as it exhibits cranking performance at the interface between them, and like an oxidation catalyst, it completely oxidizes and eliminates the entire amount of oil that scatters and adheres, and does not stagnate, so there is no need for one layer itself to be porous. do not have. Therefore, its thickness can be reduced to a level that does not affect aesthetics. A cranking catalyst layer having a predetermined specification is formed through a firing process at 700° C. for 5 to 7 minutes depending on the composition and amount of the spray-applied mixture.

In this example, since the binder contains TiO2, the color after firing is white. Incidentally, one of the characteristics of this cranking catalyst is that it is possible to develop a variety of colors by adding one of various pigments. It is therefore optional to incorporate all pigments into the mixture for spray application.

In the embodiment configured as described above, a cracking catalyst layer 18 is formed on the inner wall surface of the heating chamber 2, and the cracking catalyst layer 18 has a strength comparable to that of ordinary enamel and has a dry surface.
), even if heating products such as oil generated during cooking adhere to the catalyst layer 18, the cracking action, that is, the thermal dissociation of fatty acids proceeds and evaporates. It also acts to prevent polymerization of substances that are difficult to thermally dissociate, and prevents oil from seizing on the cranking catalyst layer. As already mentioned.

For substances that polymerize and turn into mail, the polymerization is completely inhibited at the point of contact between the catalyst surface and the dirt substance, and only the seizure on the catalyst surface is prevented, so polymerization and mail formation progresses in areas that do not come into contact with the catalyst. It turns out.

However, even in this case, the inside of the heating chamber can be cleaned extremely easily.

Further, since the cranking catalyst has the same strength and surface smoothness as ordinary enamel, it has the advantage of being scratch resistant and easy to clean.

Since the present invention is as described above, it cannot be expected that the heating products scattered from the heated food during heating will be reduced over time as in the case of an oxidation catalyst, but the heating products will be removed from the entire wall surface. This has the effect of making it easier to clean the inside of the heating chamber due to its ability to prevent burn-in.

However, the catalyst of the present invention, which exhibits only the cranking performance, does not need to be porous at all and can be used with the surface smoothed to the same extent as ordinary enamel. There are aesthetic issues regarding the surface finish, so I think there are demands for a completely glossy surface or a certain degree of roughness, but these can be developed without taking into account the entire catalytic performance. It is. In the case of oxidation catalysts, the color of the catalyst layer after firing is black or blackish brown due to its composition (although gray ones are also made,
The term black here includes the tray as well.On the other hand, it can be said that the color development of cranking catalysts is completely free. If you look at recent open and open 1/2 units, the colors and alignment of the two-body casing have become richer, but the color inside the heating chamber is monotonous and unconventional. In the present invention, the heating chamber wall can be wrapped in various ways while taking into account the color of the main body casing.

In addition, in the case of a cranking catalyst, its melting point is 600 to 6
As expected to some extent from the fact that the temperature is 50°C, the softening point is approximately 500°C, which is a relatively high temperature.

Even when the fired catalyst layer comes close to a gas burner or an electric heater, it does not easily soften, and can withstand quite severe usage environments. This point is also much better than conventional oxidation catalysts.

In addition, the strength of the catalyst layer itself and the adhesion strength between the catalyst layer and its base material can be made comparable to that of ordinary enamel, and the resistance to water and steam is also comparable, so it has a steam heating function. It can also be safely used in cookers.

In Example 9, a cracking catalyst layer was completely fired on an aluminized steel plate, but the same effect can be obtained by forming a cracking catalyst layer on an ordinary enameled steel plate.

Also cranking catalysts, binders, and milling agents.

Needless to say, you can get it.

[Brief explanation of drawings]

This is the cause. 1... Book body. 4.6, 9, 10.11...Heating chamber wall surface. 16... Base metal. 17...Aluminum plating. 18... Cracking catalyst layer. Applicant: Hitachi Thermal Appliances Co., Ltd.

Claims (1)

[Claims] A cooking device characterized in that a cracking catalyst layer is formed on the inner wall surface of a heating chamber (2).