Title : "method for the production of a heatable ceramic plate and the plate obtained"

Abstract

The present patent application relates to a method for manufacturing a ceramic plate-type utensil. This utensil is specifically designed to keep the food placed on it at a consistent temperature. In particular, the present patent application concerns a method for producing a heatable ceramic plate, which is compatible both technologically and economically with ceramic product manufacturing techniques. The method aims to produce a heatable plate that maintains its aesthetic appearance without alteration and does not present substantial differences compared to known types of plates. The obj ect of the present patent application finds application in the field of manufacturing household utensils, particularly in the sector of tableware and more specifically ceramic tableware, and even more particularly in porcelain or maiolica.

Description

[0001] Title: "METHOD FOR THE PRODUCTION OF A HEATABLE CERAMIC PLATE AND THE PLATE OBTAINED"

[0002] DESCRIPTION

[0003] The present patent application relates to a method for manufacturing a ceramic plate-type utensil. This utensil is specifically designed to keep the food placed on it at a consistent temperature. In particular, the present patent application concerns a method for producing a heatable ceramic plate, which is compatible both technologically and economically with ceramic product manufacturing techniques. The method aims to produce a heatable plate that maintains its aesthetic appearance without alteration and does not present substantial differences compared to known types of plates. The object of the present patent application finds application in the field of manufacturing household utensils, particularly in the sector of tableware and more specifically ceramic tableware, and even more particularly in porcelain or maiolica.

[0004] According to known techniques, a utensil of the type ceramic, porcelain, or maiolica plate is made through a series of steps that, depending on the production methods, may vary slightly but essentially consist of:

[0005] Preparation of a clay mixture,

[0006] Molding for creating the desired shape, known as the forming phase, which is carried out at an industrial level using stamping techniques .

[0007] Drying,

[0008] Optional decoration,

[0009] First firing at a high temperature, approximately between 800°C and 1400°C, Glazing,

[0010] Second firing at a temperature generally higher than the first firing,

[0011] Cooling and finishing.

[0012] Tools made using the above-mentioned method or, in general, ceramic, porcelain, or maiolica utensils have the disadvantage of cooling the contents quickly. This is because they have a large surface area for heat exchange with the surrounding air on one side and with the contents on the other, and they are made from materials with low thermal conductivity.

[0013] This has led to the proposal of various solutions to improve the maintenance of the temperature of tableware. It is well known that both in the catering industry and in domestic settings, there is a need to keep a cooked dish at the right temperature while waiting to be served, as well as the need to prevent the dish from cooling down quickly once it has been served.

[0014] It is well known that common serving dishes allow the maintenance of the dish's temperature for a short period; typically, in fact, a serving plate is made of ceramic material, which is itself known for its heat-conducting properties.

[0015] Although plastic is a material with lower heat conductivity compared to ceramic, plates made of plastic material present a series of other disadvantages compared to ceramic, making them unsuitable for certain contexts.

[0016] Conventionally, in order to ensure that a serving plate allows the dish to arrive at the table hot and to keep the dish at the desired temperature for as long as possible once served, it is a common practice to warm the plates.

[0017] A well-known solution, therefore, involves the use of appropriate heating devices— commonly called "plate warmers "—which consist of a compartment or container with a typically front opening. Inside, there are heating elements, usually electric serpentine heaters or electrically powered heating components.

[0018] Inside the dish warmer cabinet, a series of plates are placed, which are heated to a temperature ranging between 60°C and 80°C for several hours. When the dish is cooked and ready to be served, the compartment / container is opened, a heated plate is taken out, the dish is placed on top of it, and then it is served.

[0019] The aforementioned solution, commonly employed in establishments such as restaurants or similar venues, entails a series of disadvantages as detailed below. Firstly, the aforementioned solution requires a dedicated and adequate space for the housing of the compartment / container, a requirement that may not be feasible in the case of small-sized professional kitchens and is particularly challenging in domestic environments .

[0020] Furthermore, the aforementioned solution involves electrical energy consumption that impacts the operational costs of the facility, whether professional or domestic. nTo partially address the disadvantages associated with the solution of the type described above, prior art discloses known solutions aimed at developing means that entail lower energy consumption and are suitable for use in both domestic and professional environments, with a reduced footprint. The patent application US4505252 describes the implementation of a plate featuring an internal cavity within which wax is contained.

[0021] During the cooking phase, according to the well-known technique referred to as the "lost wax technique, " the wax evaporates, thereby leaving an internal air cavity. However, this cavity does not provide a prolonged period of thermal insulation to limit the cooling of the dish placed on the plate. nConventionally, this type of solution comprises a heating plate connected to the electrical network, on which a ceramic plate is placed.

[0022] Other known solutions in the prior art do not include the association of devices to the electrical network but rather a flat structure capable of containing a heated fluid, typically water, within the body of the plate itself. For example, application DE10060054 describes the implementation of a pair of elements wherein a first element comprises a concave structure formed by a pair of spaced walls and an inlet through which a predetermined amount of hot water is introduced.

[0023] Within the concavity of the first element, a second element is inserted, designed to contain a food item, which is maintained at a desired temperature through heat transfer from the hot water present in the first element According to what i s disclosed in the aforementioned document , upon the occurrence of the cooling of the food, the second element i s l ifted, the first element is emptied of the cooled water, and subsequently re fi lled with hot water .

[0024] The above-mentioned solution thus entails a time-consuming procedure and represents a relatively inef fective approach, since the water sti ll needs to be heated— potential ly multiple times— and during the interval between the emptying and refilling o f the first element , the food inevitably cools down .

[0025] For dishes and tableware that must be placed empty on the table or handed from person to person, the device described in the aforementioned document is unsuitable , as it would render the tableware exces sively bulky .

[0026] Other solutions known in the prior art describe dish structures or the li ke that have been suitably modi fied in order to allow the insertion, at their base, of a metal element that has been previously heated .

[0027] For example, US 1049385 describes the structure of a deep plate which includes a through opening at the base , within which a metal plate , previously heated, is slidably inserted .

[0028] However , the aforementioned solution does not constitute an ef fective solution, as it requires the time-consuming operation of inserting and removing the heating element , resulting in a loss o f both time and e ffectiveness .

[0029] In the prior art , solutions are also known that involve the creation of dual-chamber utens il s , these utensils being intended for maintaining the temperature o f the food contained therein .

[0030] For example , patent application US 4485636 describes a substantially cyl indrical dual-chamber container that includes a base chamber extending laterally and downward, equipped with a diaphragm to allow, during the expansion phase due to the refrigeration of the water placed in the chamber , the escape of any air present .

[0031] The manufacturing process of the container described in the aforementioned document there fore involves a production method that i s not compatible with the commonly known production process for ceramic plates . As such, the teachings of the aforementioned document do not allow for the creation of a method for producing a ceramic plate that includes a cavity in its lower surface , into which a fluid with high thermal inertia is inserted, the fluid being substantially contained within the finished ceramic plate .

[0032] Document JP2000107003 describes the production of a teapot that has been suitably improved in order to enhance its thermal insulating properties .

[0033] In particular, the invention described in the aforementioned document consists o f a hollow body that is introduced into the body of the teapot , the hollow body being spaced apart from the inner surface of the teapot, thereby creating a gap between the outer surface of the hol low body and the inner surface o f the teapot , with said gap being fi lled with thermal insulating material .

[0034] According to the di sclosure in the aforementioned document, the method for manufacturing the described invention involves producing the hol low body in ceramic and providing it with a spout for the exit o f hot beverage, producing the teapot body in ceramic, said body having an opening where the spout o f the hollow body i s accommodated once inserted into the teapot body, welding the ceramic hol low body to the teapot body, firing and f inishing the hol low body / teapot body assembly, f il ling the space between the hol low body and the teapot body with thermal insulating material , the fi ll ing being achieved by inj ecting the thermal insulating material through a hole made at the base of the teapot body, with the hole being sealed at the conclusion of the method .

[0035] The manufacturing process o f the teapot described in the aforementioned document there fore involves a production method that i s not compatible with the commonly known production process for ceramic plates . As such, the teachings of the aforementioned document do not allow for the creation of a method for producing a ceramic plate that includes a cavity in its lower surface , into which a fluid with high thermal inertia is inserted, the fluid being substantially contained within the finished ceramic plate . WO16069349 describes the production of an article of the type of plate, said plate being suitably shaped for the purpose of retaining heat and thereby maintaining the temperature of the food.

[0036] According to the disclosure in the document, the plate comprises a surface on which food can be placed, an internal compartment, a phase change material within the internal compartment, and an electrically conductive element within the internal compartment which is thermally coupled to the phase change material.

[0037] According to the aforementioned document, the phase change material is designed to melt in response to the heating of the electrically conductive element by an electromagnetic induction heater; furthermore, the electrically conductive element is present in an amount such that when the electrically conductive element is heated by the electromagnetic induction heater, all or at least a significant portion of the phase change material melts.

[0038] According to the disclosure in the aforementioned document, the phase change material is sufficiently close to the food placement surface so that at least part of the heat emitted by the phase change material while cooling after being melted is absorbed by the food on the food placement surface.

[0039] In some exemplary embodiments, the phase change material may be wax, a hydrated inorganic salt, or another type of material that undergoes a phase change under appropriate conditions, and the electrically conductive element may be made of metal wool, sheet metal, or iron. GB2522207 describes the creation of a serving plate comprising a lower surface that includes an internal cavity. According to the invention described in document D4, the internal cavity is filled with phase change material, such as wax. According to the description, the wax is inserted into the cavity by injection through a hole made in the lower surface of the serving plate.

[0040] According to the aforementioned document, the invention is realized by producing the main body with a lower cavity, into which the wax is introduced.

[0041] As with the inventions described in the previously cited documents, the manufacturing process of the invention described in document D4 is neither advantageous nor compatible with the commonly known production process for a ceramic plate, without significantly altering its shape characteristics.

[0042] Patent application US20060219712 concerns the production of a dish of the plate type that can be used in a microwave oven, capable of absorbing energy in a short time and releasing it as heat for an extended period.

[0043] According to the aforementioned document, the plate is made up of three rigid elements, with a first upper element having the typical characteristics of a plate, said first upper element cooperating with a second lower element to form a sealed cavity.

[0044] In particular, the second lower element is made of microwave- transparent material and contains a mass of solid material.

[0045] Specifically, the mass of solid material contained in the sealed cavity consists of a homogeneous mixture of red clay, stoneware, or other ceramics, with a small percentage of iron filings or particles. The solutions described in the aforementioned documents involve manufacturing processes that are not compatible with the known techniques for producing ceramic products.

[0046] In particular, during the first and second firing stages, the products described in the aforementioned documents could not be obtained, as the high temperatures to which the product would be subjected would cause the evaporation of the phase change material inserted within the product itself, as well as the melting of any electrically conductive metal elements contained therein.

[0047] Patent application EP3562355 describes an alternative solution, namely the creation of a ceramic tableware article comprising a passive thermal storage means, said article comprising at least one ceramic shell defining an internal cavity that houses the thermal storage means, said shell defining an inner edge that delineates a communication opening between the internal volume of the shell and the exterior of the plate, said plate comprising a means for sealing the communication opening made of a thermosetting material that fills the opening flush with the outer wall of the shell. According to the aforementioned document, in a preferred embodiment, the passive thermal storage means comprises a gel.

[0048] According to the aforementioned document, the method for manufacturing the plate consists of: forming the ceramic shell by casting the slip into a mold of the desired shape, said mold including a space for the formation of the cavity into which the slip is introduced, hardening the slip in contact with the mold wall and allowing the non-hardened slip to exit through an appropriately made opening, drying, firing, and glazing according to known techniques, injecting a thermal storage medium through the opening made in the shell, sealing the opening using resin or polymer.

[0049] In an alternative embodiment, the product described in the aforementioned document is obtained by separately manufacturing two semi-shells, each made using known techniques and shaped in such a way that they can be joined and complement each other to form, once assembled, an internal cavity into which the thermal storage medium is injected.

[0050] The processes described in the aforementioned document involve a number of disadvantages in terms of time for manufacturing, as well as potential disadvantages in terms of the performance of the resulting product, said disadvantages being caused by the presence of residual air in the cavity following the phase where the nonhardened slip exits .

[0051] Consequently, once the thermal storage medium is injected, during the thermal expansion of the medium subjected to heating, the expansion of the residual air also occurs, with the risk of overpressure and subsequent plate rupture.

[0052] This procedure entails a significant disadvantage in terms of time and various production stages, as well as high costs.

[0053] The purpose of the invention claimed in this patent application is therefore to overcome the disadvantages of the prior art described thus far, particularly by providing a method for obtaining a ceramic plate that allows for maintaining the temperature of the food placed in it, while being advantageous compared to the methods known in the prior art.

[0054] In particular, the invention claimed in this patent application relates to the method for manufacturing a heatable plate and the product obtained thereby, said method involving the creation of a single monoblock that undergoes the first and second firing stages as well as the glazing stage, said monoblock including an internal cavity into which a thermal storage medium is injected at the end of the process.

[0055] Brief description of the figures

[0056] The invention claimed in this patent application is depicted, by way of example and not limitation, in the attached drawings in which: Figures 1, 2, and 3 show schematic views of the plate subject of the present patent application.

[0057] Detailed description

[0058] With reference to the attached figures, the invention claimed in this patent application is indicated by reference number 100.

[0059] According to the invention claimed in this patent application, the plate (100) comprises a substantially circular upper surface (100.1) and a substantially circular lower surface (100.2) , with the lower surface (100.2) having a diameter that is less than or at most equal to the diameter of the upper surface (100.1) .

[0060] According to the invention claimed in this patent application, the upper surface (100.1) and the lower surface (100.2) are spaced apart to form a cavity (1) that extends along the peripheral surface of the lower surface (100.2) .

[0061] According to the invention claimed in this patent application, the lower surface (100.2) includes a first hole (2.1) and a second hole (2.2) , said first and second holes (2.1, 2.2) being positioned on the peripheral surface of the lower surface (100.2) so as to serve as a passage between the internal space of the cavity (1) and the external space of the inner surface (100.2) . In particular, the first hole (2.1) and the second hole (2.2) are positioned at the ends of the diameter (d) of the lower surface (100.2) .

[0062] According to the invention claimed in this patent application, the manufacturing of the plate (100) as described herein includes: The manufacturing of the plate (100) having a substantially circular upper surface (100.1) and a substantially circular lower surface (100.2) , with the upper surface (100.1) being spaced apart from the lower surface (100.2) to create a cavity (1) that extends along the peripheral surface of the lower surface (100.2) , said peripheral surface of the lower surface (100.2) having a first and a second hole (2.1, 2.2) , each positioned at the ends of the diameter (d) of the lower surface (100.2) . This manufacturing takes place using known techniques and includes the following stages: forming using a mold, drying, optional decoration, first firing at high temperature, glazing, second firing at high temperature, cooling, and finishing.

[0063] Filling the cavity (1) with a high thermal inertia material in gel form through the first hole (2.1) , causing the exit of the air present in the cavity (1) through the second hole (2.2) . Sealing of the first hole (2.1) with a sealing material.

[0064] Insertion into the second hole (2.2) of a control device, such as a pressure control valve.

[0065] According to the invention claimed in this application, the plate (100) manufactured as previously described is first introduced into a device such as a microwave oven and heated to a temperature between 50°C and 60°C.

[0066] Subsequently, the cooked dish is placed on the heated plate (100) , which is then served.

[0067] The invention, as previously described, therefore advantageously achieves the goal of creating a heating plate without altering the commonly known manufacturing process.

[0068] Moreover, the presence of a second hole on the lower surface of the plate thus manufactured prevents the presence of air volume within the cavity and allows for the control of the internal pressure exerted by the expansion of the gel during heating or by any res idual air pres sure , thanks to the insertion of a pressure control valve in the second hole .

[0069] The plate manufactured as described thus advantageously achieves the goal of keeping the dish contained within it heated, while maintaining the same aesthetic appearance as a common plate, without impacting the plate ' s visual des ign .

Claims

CLAIMS1. Method for the production of a heatable ceramic plate (100) said method comprising the steps of forming the plate using a mold, drying, first firing, second firing, cooling, and finishing said method being characterized in that the ceramic plate produced consists of an upper circular surface (100.1) and a lower circular surface (100.2) , said lower surface (100.2) having a diameter smaller than or at most equal to the diameter of the upper surface (100.1) , werein the upper (100.1) and lower (100.2) surfaces are spaced apart to form a cavity (1) that extends along the perimeter of the lower surface (100.2) , and werein the lower surface (100.2) has a first hole (2.1) and a second hole (2.2) , said first and second holes (2.1, 2.2) being located on the perimetral surface of the lower surface (100.2) so as to provide as a passage between the interior of the cavity (1) and the exterior— of the inner surface (100.2) said first hole (2.1) and the second hole (2.2) being positioned at diametrically opposite portions of the lower surface (100.2) wherein at the end of the finishing process, the cavity (1) is filled with material of high thermal inertia, said filling occurring through the first hole (2.1) so that any air present in the cavity escapes through the second hole (2.2) .

2. Method as claimed in claim 1, characterized by the fact that the material of high thermal inertia is in gel form.

3. Method as claimed in claims 1 and 2, characterized by the fact that the first hole (2.1) is sealed by applying sealing material .

4. Method as claimed in claims 1, 2 and 3, characterized by the fact that a pressure control valve is applied to the second hole (2.2) .

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