PT109068B - MULTI-USE CERAMIC ARTICLE FOR COOKING FOODS AND RESPECTIVE MANUFACTURING METHOD - Google Patents

Abstract

The present invention relates to an article of ceramic for cooking food and to the manufacturing method. THE CERAMIC ARTICLE OBJECT OF THE PRESENT INVENTION IS IN CERAMIC (PORCELAIN), FOR FOOD COOKING, AND ADAPTED TO SUPPORT VARIOUS SOURCES OF HEAT, INCLUDING THE OVEN TO THE FIREPLACE, ELECTRIC OVEN, GAS OVEN, MICRO-WAVES, GAS STOVE AND ELECTRICAL STOVES, RADIATION OR HALOGEN MONITORING PLATES, SAFETY INDUCTION CERAMICS (WITH EXPLOSION IMPEDIMENT) AND TO SUPPORT STORAGE IN REFRIGERATOR OR FREEZER AND WASHING IN THE DISHWASHER, FOR ITS MANUFACTURING METHOD SPECIFICALLY PRESENT AT LEVEL OF PASTE, DESIGN AND DECALCOMANIA.

Description

DESCRIPTION

MULTI USED CERAMIC ITEM FOR COOKING FOOD AND THEIR MANUFACTURING METHOD

Technical Domain of the Invention

The present invention relates to a ceramic food cooking article and its manufacturing method. The ceramic article object of the present invention is ceramic (porcelain) for cooking food and adapted to withstand various heat sources including wood oven, electric oven, gas oven, microwave oven, gas cookers and electric stoves, radiation or halogen glass ceramic hobs, safe induction ceramics (with explosion prevention) and also to support storage in a refrigerator or freezer and dishwasher washing, for this their manufacturing method. presents specificities in folder, design and decal.

State of the Art

There are currently several setbacks in the use of objects in the kitchen area, in different materials depending on the type of use we want to give it, see:

(a) For cooking in a wood oven, electric or gas oven, a plastic utensil may not be used;

(b) For cooking in a microwave oven, a metal utensil may not be used;

c) For cooking on an induction hob, it is not possible to use a utensil made solely of glass, plastic or ceramic. In particular, however, it is known that by applying to the bottom of a ceramic container an electrically conductive layer capable of generating eddy currents makes it possible to cook on an induction hob;

(d) for cooking on a gas cooker or on an electric cooker or on a ceramic or radiation glass ceramic hob, ie in order to cook by bringing in direct contact with the flame or by an electrical resistance or intense light not It is possible to use an article made only of conventional plastic, ceramic or glass, with the exception of Pyrex - arcoflame.

In addition to the existing setbacks mentioned above, which implies that we have various utensils of various materials depending on the type of equipment we will use in the preparation of our food, we must also take into account that:

• Cooking utensils must satisfy various cooking modes offered by different heat sources.

• To achieve satisfactory effects when cooking in a microwave oven or induction hob, it is essential to make the metal part compatible with eddy currents compatible;

• For satisfactory effects when cooking on a gas stove or induction hob, it is essential to make compatible the metal part capable of generating eddy currents in direct contact with a flame, ie not to alter or destroy the metal part in any way. contact with the flame;

• to allow the utensil for cooking can pass from a storage in the freezer, where the storage temperature substantially in the range of - 20 ⁰ C for cooking on a gas hob, where the flame temperature is above 500 ⁰ C and also to allow rapid heating on an induction hob, it is essential to reduce the coefficient of thermal expansion of the cooking utensil;

• Cooking utensils must meet certain hygienic requirements, one of which concerns the low porosity of the article to minimize a retention of food and / or cleaning liquids within the pores of the utensil. It is indispensable that the cooking utensil has sufficient thermal and mechanical resistance to prevent the appearance of micro cracks that make it likely to retain food and / or cleaning liquids.

Thus, it is found that there is currently a procedure which consists of applying to the outer part of an electrically conductive layer, carried out by a transfer deposition method of said electrically conductive layer by means of a silver-based metal film, constituting a conductive layer of electricity. This feature is particularly advantageous for allowing the use of an induction hob. The heat distribution to the sides of the cooking utensil is currently insufficient, however, which limits some cooking operations, requiring preheating and a reasonable volume of liquid to allow cooking in the gas and heat sources. induction.

All these problems are solved with the present invention, since the ceramic article object of the present invention has:

• a geometrical configuration of the outer base that more efficiently and evenly distributes heat from the outer base to the side walls of the appliance in the heat sources to be used, such as gas stoves and electric cookers, radiation or ceramic glass hobs. halogen and induction ceramics, thus allowing for better heat distribution, which makes it more efficient than products found in the nearest prior art;

• a geometry and ceramic paste in its constitution that, when using a heat source such as the gas stove, avoids the mass concentration in the union of the base of the utensil with the side walls, which makes it difficult to pass heat to the sidewalls;

• a geometry that allows the application of the conductive layer of electricity to the base next to the utensil sidewall, which using an induction heat source allows much better heat distribution to the utensil sidewalls.

With these new features it is possible to perform certain cooking operations without preheating the cooking utensil and allows for more diversified cooking operations, as long as not dry, such as sautéing, stewing, besides the already This is the unexpected technical effect of the present invention, that is, a multipurpose ceramic product which can be used for baking, stewing, braising, etc., as it allows various modes of cooking in different cooking modes. different heat sources such as electric oven, gas oven, microwave oven, gas cookers and hobs, radiation and halogen glass ceramic hobs and induction hobs, as well as freezer and refrigerator storage, dishwasher use and with additional safety conditions in the use of induction hobs, being attached to this patent application tests performed to the prosthesis invention in the competent authorities and proving the said effects.

To achieve the above advantages and effects the present invention provides:

1) a specific and innovative ceramic paste composition;

2) a geometry of the configuration at the distinct outer base. It is noted that the geometry of the outer base allows the application of decal for better heat distribution across the sides of the appliance, in particular in heat sources from halogen and radiation ceramic hobs and induction hobs;

3) a decal designed for the optimization of the conductive layer of electricity, which in addition to the use of the appliance in different heat sources (electric oven, gas oven, microwave oven, gas stoves and electric plates, glass ceramic hobs by radiation and halogen) for cooking, also allows use on the induction hob. These platinum rows have been developed with the characteristic of preventing the explosion of the utensil, even by misuse, thus adding a safety factor in its use in induction hobs.

In the prior art search are found the following patent documents: EP2431345B1; US8714403B2; EP2361896A1; W02011055043A3; EP2496120A2; FR48438260853;

FR2959405A1; WO9634923A1; FR2643023A1; USD0688084S;

USD0659463S; USD0667273S; USD0653909S; USD0653496S;

USD0549040S; USD0557062S; USD0479780S; USD0459635S;

USD0427489S and USD0312189S. We add that none of the identified documents reveal products with the characteristics and effects of those of the present invention.

Description of the invention

The present invention relates to a multipurpose ceramic food cooking article and method of manufacture, which describes the technical characteristics.

As noted above, the identified technical effects are achieved by ceramic paste, outer base geometry and decal, so it is important to define each of these product specificities.

The ceramic paste from which the ceramic part in question is produced has the following composition: quartz (silicon dioxide), kaolin (aluminum silicates), alkaline earth metals such as aluminum oxide and magnesium oxide, and metals. alkali in pre-determined mass / mass (w / w) percentages. Preferably, the ceramic paste contains 35% (w / w) to 45% (w / w) quartz, 15% (w / w) to 25% (w / w) silicates, 35% (w / w) to 45% (w / w) aluminum oxide, 5% (w / w) to 10% (w / w) magnesium oxide, and 0.5% (w / w) to 2% (w / w) oxides lithium where the sum is 100 or even slightly less than 100 if the paste contains other compounds or minor impurities.

The specificity of the ceramic paste with which the present invention is produced, in particular the incorporation of alkali metals, enables the ceramic product to increase its conductivity and resistance to thermal shock.

The current need for the ceramic utensil to start cooking food is avoided.

preheating cooking and other

Defined the ceramic paste of the product that reaches the geometry of the recess the proposed objectives was studied the configuration in the outer base, which particularity represented, freight or circular, in figure 2 by reference number ² (1), which concerns the position of a circular recess, less than the

- 8 perimeter of the article, which may have discontinuities (4), with the particularity of being preferably 9.24mm inwardly from the base, a space where a row of platinum per decal can be applied, which allows a faster and homogeneous preheating / heating. In fact, if this circular recess (1) did not exist at the base of the product, the part would be damaged in the cooking of the enameled part. The position of this circular recess (1) is hereinafter referred to as freight.

For explanation of the technical effect described above, that of the part not being damaged in cooking, it should be noted that the present invention is completely enamelled, including the base, which is also required for decal application. Once the article has been completely enamelled, the freight enamel (1) is removed by cleaning.

This freight cleaning operation allows the enamel piece to be baked, preventing the base from being in contact with the oven refractory plates, since only the freight (1) is in contact with the refractory plate. In case of contact of enameled surfaces with the refractory plates, the present invention will be damaged. The freight (1) must have a minimum height of 3mm that prevents contact of the base of the article with the refractory plates and a maximum height of 6mm that allows the induction plate activation, shown in figure 2. The clearance of the freight, shown In Figure 2, in relation to the outer perimeter of the base it must be between 9 and 10 mm, that is, the distance is sufficient for a row of decal platinum to be applied in this interval.

It only remains to define the decal designed for the optimization of the conductive layer of electricity, which refers to a set of platinum rows (3), which are circular magnetic strips in mass (not liquid) that should have thicknesses. totaling a weight of 0.90gr al, 25gr platinum. Particularly the outermost row of platinum (2) is applied between the end of the base and the utensil freight (innovative feature).

The number of platinum strips (3) may vary depending on the size of the part base. As for decal configuration, specifically applying a platinum row between the freight (1) and the outer perimeter of the utensil base is essential for better heat distribution and homogenization to the utensil walls, ensuring greater thermal resistance when of induction.

For the sake of descriptive sufficiency of the product, which makes it possible to cook food in different separate heat sources, the method of manufacture of the article, which included the following steps:

1) prepare a ceramic paste comprising quartz (silicon dioxide), kaolin (aluminum silicates), alkaline earth metals such as aluminum oxide and magnesium oxide, and alkali metals in predetermined mass percentages. In other words, the ceramic paste contains 35% (w / w) to 45% (w / w) quartz, 15% (w / w) to 25% (w / w) silicates, 35% (w / w) m) 45% w / w aluminum oxide, 5% w / w 10% w / w magnesium oxide, and 0.5% w / w 2% w / w ) of lithium oxides in which the sum is 100 or even slightly less than 100 if the paste contains other compounds or minor impurities;

2) preparation of a ceramic slip by stirring the ceramic paste in an aqueous suspension:

(a) diluting the ceramic slurry in the suspension to an aqueous suspension having a density of between 1,750 and 1,850 and a viscosity of between 280 and 350 degrees Gallenkamp (viscosity measured with a torsion viscometer on the Gallenkamp apparatus type);

b) Processing the liquid pulp (including by filter press) for a sufficient time, preferably about 2h, and under a predetermined pressure until a plastic pulp with a water content has been reduced by 16% (m / m) and 20% (w / w);

3) shaping the ceramic slip to obtain a ceramic piece in the proper shape (conformation), which consists in obtaining the desired shape of the ceramic article. For example, a round casserole (Figure 1) / cocotte, or tajine. This step may be carried out using conventional techniques such as pottery, pressure filling, counter-molding, mechanical pressing, isostatic pressing of ceramic keratin or powder spray;

4) cooking the shaped article carried out at a ceramic firing temperature between 980 ° C and 1010 ° C, for a time between 4 and 5 hours (information from 4h rising to 5h descending = 9h total) to obtain a very porous intermediate ceramic product which allows the absorption of enamel;

5) Preparation of the enamel powder, with a density between 1,3gr / cc to 1,5 gr / cc, which should include quartz (silicon dioxide), kaolin (aluminum silicate), aluminum oxide, magnesium oxide. and potassium silicate, in predetermined mass percentages, preferably: contains 60% (w / w) to 80% (w / w) of quartz, 10% (w / w) to 20% (w / w) aluminum oxide, 5% (w / w) to 10% (w / w) of magnesium oxide, and 0.5% (w / w) to 5% (w / w) potassium oxides where the sum is equal at 100% (w / w)). Note that the enamel powder has a mineralogical composition rich in cordierite, corundum, quartz and mullite, adjacent to the mineralogical core composition of the ceramic product obtained in step 7), described below. Enamel powder may also have a cordierite content of between about 40% (w / w) and

60% (m / m) and a percentage of corundum between about

8% (w / w) and 15% (w / w);

6) preparing an enamel slip by stirring the aqueous suspension enamel powder to a density of 1,300 to 1,700, with or without sizing additives which may promote the adhesion of the enamel slip to the ceramic paste;

7) Enameling of the ceramic piece proceeds by coating the intermediate ceramic product with a layer of enamel slip. Enameling is performed by a method of dipping and / or spraying the enamel slip with an application thickness of between 100 microns and 200 microns. Note that the glaze slip must have a composition similar to that of the ceramic paste, ensuring that the enamel layer on the cookie body after baking will have the same thermal and mechanical properties as the cooked ceramic paste, particularly in regards low porosity, low coefficient of thermal expansion and high mechanical strength;

!) baking the enameled workpiece at a ceramic firing temperature of between 1360 ° C and 1390 ° C, adapted to activate the cordierite combination for a time of 4 to 6 hours sufficient to achieve cordierite nucleation and crystallization and to a ceramic product having an enamel-coated core is obtained. This ceramic piece has a mineralogical composition rich in cordierite, corundum, quartz, mullite and glassy phase, with a cordierite of 40% (m / m) to 60% (m / m) and a percentage of corundum between 8%. (w / w) and 15% (w / w), and wherein said product has the following intrinsic characteristics:

• coefficient of thermal expansion: 0.19% to 0.22% at 573 ² C; between 28 and 34ppm / ° C, preferably 31ppm / ° C;

• coefficient of water absorption in a volume between 0.02% and 0.18%;

• bulk density greater than 2.6;

The cooking of the enameled ceramic piece is carried out in a reducing atmosphere.

In addition, cordierite is a mineral species consisting of aluminum magnesium silicate, A13Mg2AlSi5018 general formula. The ceramic core stroke corresponds to the ceramic paste after roughing, cutting and baking. In addition, the massive presence of cordierite (about 40% (w / w) and 60% (w / w)) is associated with reinforcement, ie corundum up to 8% (w / w) to 15% (w / w). / m). For indication, corundum, or alpha alumina, is a mineral species composed of crystallized anhydrous formula of A12O3, which is referred to as α-Α12Ο3. The hardness of the ore is 9 on the Mohs scale, making it the second hardest mineral after diamond. Cordierite has excellent heat resistance characteristics, and corundum present excellent mechanical resistance characteristics, so that its association contributes significantly to the thermal and mechanical properties of the baking product obtained by this method.

In addition, the ceramic core has a white, glassy, dense and translucent appearance after firing, which approximates the appearance of porcelain, possibly with an ivory or satin cream tone following the appearance of enamel after baking, Especially appreciated in the food industry.

In the firing step of the enameled ceramic piece is carried out according to a temperature program comprising the following successive intervals:

(a) temperature range between 100 ² C and 650 ° C over a period of 1 to 2 hours;

(b) temperature change between 650 ° C and 1000 ° C over a period of 1 to 2 hours;

(c) temperature range between 1000 ° C and 1300 ° C over a period of 1 to 2 hours with a temperature range of about 1280 ° C for a period of 100 minutes;

(d) temperature range between 1300 ° C and 1390 ° C over a period of 0.5 to 1 hours;

and) Variation temperature between 1390 ° C and 1000 ° C during a period between 0.5 and 1 hours; f) Variation of temperatures between 1000 ° C and 150 ° C during a period of between 3 and 6 hours; g) Variation temperature between 150 ° C and 30 ° C during a period of between 1 and 2 hours

The temperature cycle is particularly advantageous in allowing nucleation and crystallization of cordierite.

Additionally and for the purpose of using the appliance in an induction heat source, after step 8) an electrically conductive layer capable of generating eddy currents may be applied to the outer base of the appliance, and whose thickness is preferably between 10 and 25 microns. The application of this conductive layer, as it is at the base of the kitchen utensil, still allows its use in the microwave oven.

This electrically conductive layer embedded in a decal has the following key features:

(a) the application of platinum rows, which are magnetic bands, in circular form;

(b) application of platinum rows by mass (not liquid);

(c) Platinum rows shall have a thickness of a total weight of 0.90gr to 1.25gr of platinum;

d) The outermost row of platinum is applied between the end of the base and the freight of the utensil;

These platinum rows are designed to prevent the explosion of the appliance even from misuse, thus adding a safety factor to its use in induction hobs.

This method of applying the decal conductive layer is particularly advantageous for controlling and mastering the deposit thickness and for controlling the induction heating capability of the product by adapting the ratio between the active surface (product surface covered by the electrically conductive layer) and neutral surface (surface of the article not covered by the electrically conductive layer), improving the efficiency of the utensil by the proposed innovation with the new part configuration design.

Additionally and for fixing the decal (which incorporates the conductive layer of electricity) an additional firing is performed at a ceramic firing temperature between 800 ° C and 850 ° C for a time between 7 to 9 hours. With this additional firing, an annealed molten enamel overlay of 800 ² ° C to 850 ° C is obtained, which is particularly advantageous for protecting the metal film, in particular from scratching and washing, and also to prevent degradation and even Even destroy the metal foil when the product is placed over an electric resistance or a gas stove flame.

Brief Description of the Figures

Figure 1 - Side view of a preferred kitchen utensil. Perspective view of a preferred kitchen utensil.

Figure 2 - View of the outer base preferably of the kitchen appliance with the decal applied, where it is possible to visualize the representation on the freight base (1) and its discontinuities (4), the platinum tapes (3) and the tape. outermost plate (2), between the freight and the outer edge of the base.

Figure 3 - Preferred top view of the kitchen utensil.

Leiria, March 27, 2017

Claims (9)

1. Multipurpose ceramic food cooking item characterized by: (a) consist of ceramic paste composed of 35% (w / w) to 45% (w / w) of quartz, 15% (w / w) to 25% (w / w) silicates, 35% (w / w) m) 45% w / w aluminum oxide, 5% w / w 10% w / w magnesium oxide 0.5% w / w 2% w / w lithium oxide, kaolin and alkali metals; (b) has an outer base with a freight (1) around the perimeter and a set of non-liquid circular mass (3) rows of platinum having a thickness of a total weight of 0,90g a, 25g of platinum and the outermost row of platinum (2) is located between the outer base end and the freight (1). Article according to claim 1, characterized in that the freight (1) has discontinuities (4). Article according to the preceding claim, characterized in that the freight is located 9.24mm inwards from the outer base. Article according to Claim 1, characterized in that the platinum tapes (3) are magnetic strips. Method of manufacturing an article according to claims 1 to 4, comprising the following steps: (a) preparation of ceramic paste; b) preparation of ceramic slip by stirring the ceramic paste in an aqueous suspension with the following steps: (i). diluting the ceramic slurry in the suspension until an aqueous suspension having a density between 1.750 and 1.850 and whose viscosity is between 280 and 350 degrees Gallenkamp; (ii). process the liquid paste, preferably about 2 hours, and under a predetermined pressure until it has a plastic paste with a content of water was i; reduced between 16% (m / m) and 20% (m / m; W) modeling ceramics; gives slip ceramic in article in d) cooking of article conformed to a temperature pottery burning between 980 ° C and 1010 ° C, during one time between 4 and 5 hours; (e) preparation of the enamel powder, having a density between 1,3gr / cc to 1,5 gr / cc, which contains quartz, kaolin, aluminum oxide, magnesium oxide and potassium silicate; (f) preparing an enamel slip by stirring the aqueous suspension enamel powder to a density of 1,300 to 1,700 with or without sizing additives; (g) enameling of the ceramic piece by coating the article with a layer of enamel slip by dipping and / or spraying the enamel slip with an application thickness of between 100 microns and 200 microns and a composition similar to paste ceramics; (h) cleaning the enamel of the freight (1); (i) cooking the enamelware in a reducing atmosphere at a ceramic firing temperature of between 1360 ° C and 1390 ° C for 4-6 hours; j) application on the outer base of the platinum rows (3) and the outermost platinum row (2) between the base end and the freight (1); (k) additional firing at a ceramic firing temperature between 800 ° C and 850 ° C for a time between 7 and 9 hours. Method according to claim 5, characterized in that the enamel powder has 60% (w / w) to 80% (w / w) quartz, 10% (m / m) The 20% (w / w) aluminum oxide, 5% (m / m) a 10% (m / m) in oxide of magnesium, and 0.5% (w / w) at 5% (m / m) of oxides in potassium. Method according to the preceding claims, characterized in that the enamel powder has a percentage of cordierite between about 40% (w / w) and 60% (w / w) and a percentage of corundum between about 8% (w / w). / m) and 15% (w / w). Method according to Claim 5, characterized in that the enamel piece firing step has a temperature program comprising the following successive intervals: The) temperatures period between in between 1 and 2 100 ° C hours; and 650 ° C during one B) temperatures in between 650 ° C and 1000 ° C during one period between 1 and 2 hours; W) temperature between 1000 ° C and 1300 ° C during one period between 1 and 2 hours with landing in temperature at fence at 1280 ° C for one period in 100 minutes; d) temperature between 1300 ° C and 1390 ° C during one time between 0.5 and 1 hours; e) temperature between 1390 ° C and 1000 ° C for a period between 0.5 and 1 hours; f) temperatures between 1000 ° C and 150 ° C for a period of between 3 and 6 hours; g) temperature between 150 ° C and 30 ° C for a period of 1 to 2 hours. 9. A method according to claim 5 , characterized by the steps of applying the outer base of the platinum lines (2) (3), the burning temperature is 850 C and the time ² being 3h.