WO2005115207A1

WO2005115207A1 - Cooking utensil for induction range

Info

Publication number: WO2005115207A1
Application number: PCT/KR2004/002065
Authority: WO
Inventors: Bong-Gi Baek
Original assignee: Bong-Gi Baek
Priority date: 2004-05-28
Filing date: 2004-08-18
Publication date: 2005-12-08
Also published as: JP2005334638A; KR20040068042A

Abstract

A cooking utensil used for cooking a food item on an induction range. The cooking utensil comprises a utensil body manufactured by die casting or deep drawing in the shape of a container capable of accommodating the food item, the utensil body having a bottom heating plate; a first magnetic plate attached to a lower surface of the bottom heating plate of the utensil body; an aluminum plate attached to a lower surface of the first magnetic plate; and a second magnetic plate attached to a lower surface of the aluminum plate. Each of the magnetic plates comprises a metal plate containing a ferrum constituent, such as a steel plate, an aluminum-plated steel plate, and a plate having a predetermined degree of magnetism, for example, SUS430. The utensil body is made of aluminum. The plates are coupled by pressing or high-frequency heat fusion.

Description

[DESCRIPTION] [Invention Title] COOKING UTENSIL FOR INDUCTION RANGE [Technical Field] The present invention a cooking utensil for an induction range, in which a first magnetic plate, an aluminum plate and a second magnetic plate are sequentially stacked on a lower surface of a bottom heating plate of a utensil body manufactured by die casting or deep drawing and are coupled to the bottom heating plate by high-frequency heat fusion or pressing.

[Background Art] As generally known in the art, a cooking utensil used for cooking a variety of food items has a utensil body and a grip which is fixed to the utensil body. The utensil body possesses a bottom hea ing plate. However, conventional cooking utensils made of stainless steel or aluminum have a defect in that, due to concentration of heat on a certain portion of the bottom heating plate, the likelihood of the bottom heating plate to be deformed is increased. This heat deformation occurs to different degrees in a gas range and an induction range, so that a food item cannot be evenly cooked and thereby a taste of the food item is degraded. Specifically, in the case of a cooking utensil used for an induction range, since heat is not uniformly distributed over the entire surface of a bottom heating plate, temperature cannot be stably controlled in an induction range. As a consequence, for example, oil contained in a food item accommodated in the cooking utensil may reach an unintentionally high temperature and thus be burned away.

[Disclosure] [Technical Problem] Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide a cooking utensil for an induction range, in which a first magnetic plate, an aluminum plate and a second magnetic plate are sequentially stacked on a lower surface of a bottom heating plate of a utensil body manufactured by die casting or deep drawing and are coupled to the bottom heating plate by high-frequency welding, whereby the cooking utensil can be reliably used for the induction range due to characteristics of the magnetic plates and the bottom heating plate of the utensil body is prevented from being deformed due to a combined function of heat expansion characteristics of the magnetic plates and the aluminum plate.

[Technical Solution] In order to accomplish this object, according to one aspect of the present invention, there is provided a cooking utensil used for cooking a food item on an induction range, comprising: a utensil body manufactured by die casting or deep drawing in the shape of a container capable of accommodating the food item, the utensil body having a bottom heating plate; a first magnetic plate attached to a lower surface of the bottom heating plate of the utensil body; an aluminum plate attached to a lower surface of the first magnetic plate; and a second magnetic plate attached to a lower surface of the aluminum plate. According to another aspect of the present invention, each of the first and second magnetic plates comprises a metal plate containing a ferrum constituent, such as a steel plate, an aluminum-plated steel plate, and a plate such as SUS430, which has a predetermined degree of magnetism. According to another aspect of the present invention, the utensil body is made of aluminum. According to another aspect of the present invention, the first magnetic plate, the aluminum plate and the second magnetic plate are sequentially stacked on the bottom heating plate of the utensil body, and are coupled to the bottom heating plate by pressing or high-frequency heat fusion. According to another aspect of the present invention, the high-frequency heat fusion is implemented in a manner such that powder and adhesive agent are inserted between two adjoining plates and the plates are heat-fused one to another at a predetermined temperature for a predetermined time under a high-frequency condition. According to another aspect of the present invention, the pressing is implemented in a manner such that the second magnetic plate is defined, by a perforator, with a plurality of holes which are arranged along concentric circles and each of which is delimited by a projection extending upward from an upper surface of the second magnetic plate, that the utensil body is placed on a press die with the lower surface of the bottom heating plate facing upward, the first magnetic plate and the aluminum plate are sequentially stacked on the lower surface of the bottom heating plate, and the second magnetic plate is placed on the aluminum plate with its projections facing the bottom heating plate, and that the second magnetic plate is pressed to allow the projections to be driven into the bottom heating plate through the aluminum plate and the first magnetic plate, whereby the first magnetic plate, the aluminum plate and the second magnetic plate, which are stacked one upon another, are rigidly coupled to the lower surface of the bottom heating plate of the utensil body to serve as a bottom heating section. According to another aspect of the present invention, each of the first and second magnetic plates is made of ferrite-based stainless steel containing a substantial amount of ferrum, so that a number of electron waves are induced to promote heat generation. According to another aspect of the present invention, the cooking utensil for the induction range comprises a frying pan. According to still another aspect of the present invention, the cooking utensil for the induction range comprises a pot. According to yet still another aspect of the present invention, the first magnetic plate which is coupled to the lower surface of the bottom heating plate of the utensil body comprises an aluminum-plated steel plate, so that the first magnetic plate can be rigidly coupled to the bottom heating plate due to the presence of an aluminum constituent when the cooking utensil is made of aluminum. The present invention relates to a cooking utensil used for cooking a food item on an induction range, characterized in that a utensil body is manufactured by die casting or deep drawing of aluminum, and that a first magnetic plate, an aluminum plate and a second magnetic plate are sequentially stacked on a bottom heating plate of the utensil body and are coupled to the bottom heating plate by pressing or high-frequency heat fusion, whereby the utensil body has a four-layered bottom structure. In other words, the present invention relates to a cooking utensil used for cooking a food item on an induction range, characterized in that a utensil body is manufactured by die casting or deep drawing of aluminum to have the shape of a container capable of accommodating the food item and possesses a bottom heating plate serving as a first bottom element, that a first magnetic plate serving as a second bottom element is attached to a lower surface of the first bottom element, an aluminum plate serving as a third bottom element is attached to a lower surface of the second bottom element, and a second magnetic plate serving as a fourth bottom element is attached to a lower surface of the third bottom element, and that the second through fourth bottom elements are coupled to the first bottom element by pressing or high-frequency heat fusion. Therefore, in the present invention, due to the fact that the magnetic plates are attached to the lower surface of the bottom heating plate of the utensil body, as an alternate current is applied to an induction coil, magnetic force lines are created. Thus, when the cooking utensil having a predetermined degree of magnetism is placed on a center portion of the magnetic force lines, an eddy current is produced in a bottom heating section of utensil body so as to generate heat, whereby the cooking utensil of the present invention can be effectively used for an induction range. At this time, the bottom heating plate of the utensil body made of aluminum is prevented from being deformed due to a combined function of characteristics owned by the magnetic plates and the aluminum plate. Concretely speaking, since the plate made of a material having a predetermined degree of magnetism, such as a steel plate, is attached to the lower surface of the bottom heating plate of the utensil body made of aluminum, to allow the utensil body to be used in an induction range, the bottom heating plate is prevented from being deformed due to a low thermal expansion coefficient of the steel plate. Also, by the fact that the aluminum plate which is less deformed by heat than the steel plate is attached to the lower surface of the steel plate and the second magnetic plate is attached to the lower surface of the aluminum plate, and that the plates are coupled to the bottom heating plate by high-frequency heat fusion or pressing to constitute the cooking utensil for an induction range, the bottom heating section of the utensil body is prevented from being deformed. In the above description, each of the magnetic plates comprises a metal plate containing a ferrum constituent, such as a steel plate and an aluminum-plated steel plate, having excellent heat resistance, heat reflection characteristic, high-temperature corrosion resistance, and workability. Further, a plate belonging to a stainless steel series having a predetermined degree of magnetism, such as SUS430, can be used to constitute each magnetic plate. It is preferred that the magnetic plate comprises the aluminum-plated steel plate. The reason to this is that, since the magnetic plate is coupled to the element made of aluminum, when coupling the plates by high-frequency heat fusion to the bottom heating plate, an excellent coupling strength is achieved. It is preferred that the aluminum-plated steel plate has an aluminum-plating thickness in the range of 7-25 mm. This is because electronic induction heating of the cooking utensil by the induction range is not hindered in that range. In the above description, the first and third bottom elements made of aluminum have respectively attached to their lower surfaces the magnetic plates which have different thermal expansion coefficients. Accordingly, in the cooking utensil of the present invention, the bottom heating plate of the utensil body is prevented from being deformed thanks to ductility, thermal expansion coefficient, and so on, of aluminum. Also, the bottom heating section exhibits excellent properties in association with expansion, shrinkage, etc., due to combined characteristics of the bottom elements made of aluminum and the magnetic bottom elements. It is to be readily understood that the present invention can be applied to all cooking utensils. In this regard, FIG. 2 illustrates a frying pan as an example of a cooking utensil to which the present invention is applied. In this example, a body of the frying pan is first manufactured by die casting of aluminum. Next, an aluminum-plated steel plate, an aluminum plate and a stainless steel plate are sequentially stacked on a lower surface of a bottom heating plate of the pan body. Then, after these plates are coupled to the bottom heating plate by high-frequency heat fusion, the resultant structure experiences finishing work. Alternatively, the pan body can be manufactured by deep drawing of aluminum. The finishing work includes attaching a grip to the pan body and coating a corrosion-resistant material such as fluorine resin, on an inner surface of the frying pan which is to be brought into contact with a food item. [Description of Drawings] The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: FIG. 1 is a cross-sectional view illustrating a state wherein plates are coupled according to the present invention; FIG. 2 is a partially-enlarged side view illustrating a frying pan as an example of a cooking utensil in accordance with.an embodiment of the present invention; and FIG. 3 is a cross-sectional view illustrating a state wherein the plates are coupled to a bottom heating plate of a utensil body by a press in accordance with another embodiment of the present invention.

[Best Mode] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In the following description and drawings, the same reference numerals are used to designate the same or similar components, and so repetition of the description on the same or similar components will be omitted. FIG. 1 is a cross-sectional view illustrating a state wherein plates are coupled according to the present invention; FIG. 2 is a partially-enlarged side view illustrating a frying pan as an example of a cooking utensil in accordance with an embodiment of the present invention; and FIG. 3 is a cross-sectional view illustrating a state wherein the plates are coupled to a bottom heating plate of a utensil body by a press in accordance with another embodiment of the present invention. Methods for sequentially coupling a first magnetic plate, an aluminum plate and a second magnetic plate to a lower surface of a bottom heating plate of a utensil body according to the present invention will be described below. In a first method which is directed for high-frequency heat fusion, the first magnetic plate, the aluminum plate and the second magnetic plate are sequentially stacked on the lower surface of the bottom heating plate of the utensil body with powder and adhesive agent inserted between two adjoining plates, whereby a bottom heating section is constituted. Then, after positioning the resultant structure in a high-frequency induction furnace, a high frequency is induced at a predetermined temperature for a predetermined time, thereby coupling the plates to the bottom heating plate. In the above description, the high-frequency heat fusion is implemented at a temperature of 400-550^° C for 15-20 seconds while inducing the high frequency in the high-frequency induction furnace, so that the bottom heating section is coupled to the bottom heating plate by heat fusion. The powder inserted between two adjoining plates is aluminum welding agent such as potassium fluor aluminate (KalF4, K2A1F5 ?H20). In a second method which is directed for pressing, the second magnetic plate serving as the fourth bottom element is defined, by a perforator, with a plurality of holes which are arranged along concentric circles and each of which is delimited by a projection extending upward from an upper surface of the second magnetic plate. Next, the utensil body is placed on a press die with the lower surface of the bottom heating plate facing upward, the first magnetic plate and the aluminum plate are sequentially stacked on the lower surface of the bottom heating plate, and the second magnetic plate is placed on the aluminum plate with its projections facing the bottom heating plate. Thereafter, the second magnetic plate is pressed to allow the projections to be driven into the bottom heating plate through the aluminum plate and the first magnetic plate, whereby the first magnetic plate, the aluminum plate and the second magnetic plate which are stacked one upon another are rigidly coupled to the lower surface of the bottom heating plate of the utensil body to serve as the bottom heating section. In a third method, the second magnetic plate having projections extending upward from an upper surface thereof is coupled to the aluminum plate serving as the third bottom element by pressing. Then, in a state wherein powder (aluminum welding agent) is applied on both surfaces of the first magnetic plate serving as the second bottom element, the first magnetic plate which has powder applied thereon and the combination of aluminum plate and the second magnetic plate which are coupled to each other by pressing are sequentially stacked on the lower surface of the bottom heating plate. Thereupon, the plates are coupled to the bottom heating plate by high-frequency heat fusion, whereby the bottom heating section can be coupled to the utensil body of the cooking utensil. In a fourth method, in order to sequentially stack and couple the first magnetic plate, the aluminum pate and the second magnetic plate on and to the lower surface of the bottom heating plate, after heating the utensil body of the cooking utensil and the bottom heating section to a predetermined temperature, the plates are coupled to the bottom heating plate by pressing. At this time, it is preferred that the predetermined temperature is lower than a melting point of the aluminum. In the present invention, each of the first and second magnetic plates is made of ferrite-based stainless steel containing a substantial amount of ferrum, so that a number of electron waves are induced to promote heat generation. The second magnetic plate serving as the fourth bottom element can be formed in the shape of a capsule to cover the second and third bottom elements coupled to the lower surface of the bottom heating plate so that side surfaces of the second and third bottom elements are not exposed to the outside. Also, the reason why the fourth bottom element is formed in the shape of a capsule is in that, when coupling the bottom heating section to the lower surface of the bottom heating plate by high-frequency heat fusion, as the first magnetic plate and the aluminum plate respectively serving as the second and third bottom elements are melted, molten metal is prevented from leaking sideward, whereby the bottom heating section of the cooking utensil can render an aesthetically-appealing outer appearance. In the present invention, since the die casting procedure for manufacturing the utensil body by pouring molten aluminum into a mold and the deep drawing procedure for forming an aluminum sheet into the shape of the utensil body by a press are well known in the art, detailed description thereof will be omitted herein. While the frying pan was explained in the above embodiment, a person having ordinary skill in the art will readily recognize that the present invention can be applied to other cooking utensils for an induction range. In the above description, each of the magnetic plates respectively serving as the second and fourth bottom elements comprises a metal plate containing a magnetic constituent, such as a steel plate and an aluminum-plated steel plate, having excellent heat resistance, heat reflection characteristic, high-temperature corrosion resistance, and workability. Further, a plate belonging to a stainless steel series having a predetermined degree of magnetism, such as SUS430, can be used to constitute each magnetic plate. It is preferred that each magnetic plate has a thickness of 0.56-1 mm. The present invention is characterized in that the first magnetic plate, the aluminum plate and the second magnetic plate are sequentially stacked on and coupled to the lower surface of the bottom heating plate so as to prevent the bottom heating plate from being deformed. Also, it is preferred that the aluminum plate interposed between the magnetic plates has a thickness of 1-2 mm.

[Industrial Applicability] As apparent from the above description, the cooking utensil for an induction range according to the present invention provides advantages in that, since a bottom heating section constituted by a first magnetic plate, an aluminum plate and a second magnetic plate is coupled by high-frequency heat fusion or pressing to a lower surface of a bottom heating plate of a utensil body manufactured by die casting or deep drawing, heat resistance and corrosion resistance of the cooking utensil for an induction range are improved to prevent the bottom heating plate from being deformed by heat generated in the bottom heating section. Consequently, a food item heating effect can be maximized, and it is possible to produce a quality cooking utensil for an induction range with a minimum manufacturing cost. Namely, it is possible to optimally manufacture a cooking utensil for an induction range, which does not experience any heat deformation, and has high thermal conductivity and excellent corrosion resistance and heat resistance. While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiment and the drawings, but, on the contrary, it is intended to cover various modifications and variations within the spirit and scope of the appended claims.

Claims

[CLAIMS] [Claim 1] A cooking utensil used for cooking a food item on an induction range, comprising: a utensil body manufactured by die casting or deep drawing in the shape of a container capable of accommodating the food item, the utensil body having a bottom heating plate; a first magnetic plate attached to a lower surface of the bottom heating plate of the utensil body; an aluminum plate attached to a lower surface of the first magnetic plate; and a second magnetic plate attached to a lower surface of the aluminum plate. [Claim 2] The cooking utensil as set forth in claim 1, wherein each of the first and second magnetic plates comprises a metal plate containing a magnetic constituent, such as a steel plate and an aluminum-plated steel plate, or a late belonging to a stainless steel series having a predetermined degree of magnetism, such as SUS430. [Claim 3] The cooking utensil as set forth in claim 1, wherein the utensil body is made of aluminum. [Claim 4] The cooking utensil as set forth in claim 1, wherein the first magnetic plate, the aluminum plate and the second magnetic plate are sequentially stacked on the bottom heating plate of the utensil body, and are coupled to the bottom heating plate by pressing or high-frequency heat fusion. [Claim 5] The cooking utensil as set forth in claim 4, wherein the high-frequency heat fusion is implemented in a manner such that powder and adhesive agent are inserted between two adjoining plates and the plates are heat-fused one to another at a predetermined temperature for a predetermined time under a high-frequency condition [Claim 6] The cooking utensil as set forth in claim 4, wherein the pressing is implemented in a manner such that the second magnetic plate is defined, by a perforator, with a plurality of holes which are arranged along concentric circles and each of which is delimited by a projection extending upward from an upper surface of the second magnetic plate, that the utensil body is placed on a press die with the lower surface of the bottom heating plate facing upward, the first magnetic plate and the aluminum plate are sequentially stacked on the lower surface of the bottom heating plate, and the second magnetic plate is placed on the aluminum plate with its projections facing the bottom heating plate, and that the second magnetic plate is pressed to allow the projections to be driven into the bottom heating plate through the aluminum plate and the first magnetic plate, whereby the first magnetic plate, the aluminum plate and the second magnetic plate, which are stacked one upon another, are rigidly coupled to the lower surface of the bottom heating plate of the utensil body to serve as a bottom heating section. [Claim 7] The cooking utensil as set forth in claims 1 or 6, wherein each of the first and second magnetic plates is made of ferrite-based stainless steel containing a substantial amount of ferrum, so that a number of electron waves are induced to promote heat generation. [Claim 8] The cooking utensil as set forth in claim 1, wherein the cooking utensil for the induction range comprises a frying pan. [Claim 9] The cooking utensil as set forth in claim 1, wherein the cooking utensil for the induction range comprises a pot. [Claim 10] The cooking utensil as set forth in claim 1, wherein the first magnetic plate which is coupled to the lower surface of the bottom heating plate of the utensil body comprises an aluminum-plated steel plate, so that the first magnetic plate can be rigidly coupled to the bottom heating plate due to the presence of an aluminum constituent when the cooking utensil is made of aluminum.