Hot food system, warming base for a hot food system and method for handling hot food

Abstract

The invention relates to a hot food system comprising a heat-retaining base (2) comprising a heat storage material (1) and a crockery item (3) having a support contour on the underside of the crockery item. According to the invention, the underside of the crockery item and an upper side of the heat-retaining base (2) adjoin one another outside the support contour directly and / or at a distance of less than 0.5 mm over a contact area of ​​at least 30 cm2.

Description

[0001] The invention relates to a hot food system with a warming base comprising a heat storage material and a crockery part which has a support contour on the underside of the crockery part.

[0002] Warming bases are known in practice. These are preheated, for example, in a stacker. After a warming base is removed, a plate containing a hot meal can be kept warm for an extended period of time. This allows, in particular, the hot meal to be distributed without the hot meal cooling down too much before serving. It is also common for such warming bases, with a piece of crockery placed on top, to be covered by a cover, thus providing a degree of insulation and protection for the hot meal.

[0003] Corresponding warming bases often contain an organic phase change material, also known as wax. In addition to the designs known from practice ("Variotherm" from proHeq GmbH Hepp HOSPITALA - www.hepp-hospitala.de, "ClassicLine" from MenüMobil Food Service Systems GmbH - www.menu-mobil.com and "Heating Base HEI-DE" from ADH Systeme GmbH - www.adh-systeme.de), reference is also made to the generic state of the art according to DE 10 2013 013 736 B4 ( Fig. 12).

[0004] The familiar warming bases are designed to be combined with various tableware items, such as plates from different manufacturers. These items have a support contour on their underside, also known as a base. For example, conventional plates typically feature a circumferential projection that acts as a base, with the base forming a ring-shaped support surface both during use and on the warming base.

[0005] Conventional warming bases can be provided with a contour to prevent the plate base from slipping. Ring-shaped contours can then also secure plate bases of different diameters against slipping, at least to a certain extent. Furthermore, the conventional warming bases also feature a raised edge, which also provides a certain degree of lateral support for the tableware being held.

[0006] With the conventional heat-retaining bases, heat transfer can occur through convection, direct thermal contact via the support contour, and thermal radiation. For simplicity, the term convection also refers to situations where no direct thermal contact occurs, but rather heating occurs via air as an intermediate medium, even if the air is essentially at rest.

[0007] Due to the comparatively small contact area, direct thermal contact plays a minor role. Heating or keeping warm of the item of crockery placed on the warming base occurs primarily through convection, including heating via the air in a larger gap between the warming base and the item of crockery. At least as a rule, after a certain cooling period, a thermal gradient develops between the warmer warming base and the item of crockery placed on it.

[0008] To ensure sufficient heat transfer through the described mechanisms, the known heat-retaining bases are heated to a temperature of, for example, 110 °C to 130 °C, at which point the organic phase-change material in the form of wax melts. The melting point of the phase-change material is above 100 °C, and latent heat is released in the melting range upon cooling due to a phase change from liquid to solid.

[0009] With a uniform heat supply during heating or a uniform heat loss during cooling, the typical plateau in the phase transition occurs in the region of the melting temperature, so that the corresponding temperature can be maintained over a longer period of time.

[0010] The present invention is based on the object of providing a hot feed system which can be used more energy efficiently.

[0011] The subject matter of the invention and the solution to the problem are a warming system according to patent claim 1, a warming base according to patent claim 13 and a method for handling warm food according to patent claim 14.

[0012] According to a first aspect, the invention therefore relates to a warming system with a heat storage material-containing, in particular plate-shaped, warming base and a crockery item which has a support contour on the underside of the crockery item. According to the invention, the underside of the crockery item and an upper side of the warming base are in contact outside the support contour directly and / or over a distance of less than 0.5 mm at a contact surface of at least 30 cm. 2 (square centimeters) adjacent to each other.

[0013] Accordingly, the crockery item does not rest, or at least not only on its underside, on the upper surface of the warming base. Instead, a comparatively large contact surface of at least 30 cm 2 which enables direct thermal contact.

[0014] As described below, the upper side of the warming base can be shaped in such a way that the support contour, intended as a base, does not make direct contact with the underside of the crockery item. A support contour in the form of a circumferential crockery base can, for example, be accommodated in an associated recess, which can, in particular, have a depth of more than 3 mm relative to the contact surface.

[0015] Within the scope of the invention, the warming base and the crockery part are suitably matched to one another. It is consciously accepted that the warming base is not equally suitable for all crockery items with different contours on their underside. Rather, within the scope of the invention, a specific system is provided in which the shape of the underside of the crockery part is precisely adapted to the top of the warming base, particularly with regard to the support contour on the underside of the crockery part and the corresponding recesses on the top of the warming base.

[0016] Within the scope of the invention, heat is transferred largely from the warming base to the dishes through direct thermal contact. The aim is for the dishes to rest directly on the contact surface, although a small gap cannot always be ruled out in some places due to manufacturing reasons or tolerances. Within the scope of the invention, the distance in the area of ​​the contact surface is at least less than 0.5 mm. Furthermore, it is provided that the dishes actually rest directly on the warming base at least in sections, even if the described distance of less than 0.5 mm still remains in some sections.

[0017] The larger proportion of heat transfer through thermal contact results in a fundamentally different design of the overall system compared to conventional hot-feed systems. The greater proportion of direct thermal contact results in better heat transfer, which in turn reduces losses to the environment. Another important aspect is that large temperature gradients and temperature differences are not necessary to achieve the specified temperature for the item of cookware, meaning that the warming base generally needs to be heated less.

[0018] As is known per se, a phase-change material, in particular an organic phase-change material, which in practice is also referred to as wax, can be provided as the heat storage material. The phase-change material is usually arranged in an interior space of the heat-retaining base.

[0019] For example, the phase-change material can be arranged between two cover layers, which are formed, for example, from stainless steel sheet. Stainless steel can be formed into the desired shape by sheet metal forming, particularly punching or deep drawing.

[0020] Within the scope of the invention, in particular due to the changed heat transfer, a phase change material with a transition temperature and in particular a melting temperature between 50 °C and 90 °C, in particular between 63 °C and 83 °C can preferably be provided.

[0021] While the melting temperature of known heat-retaining bases is typically above 100 °C, for example, between 110 °C and 130 °C, the invention provides a lower transition temperature, whereby the heat-retaining base needs to be heated less intensely to initially activate and, in particular, melt the phase-change material before use. Accordingly, this results in significantly lower energy consumption, while significantly lower temperature losses occur during heat-retaining and subsequent handling due to the reduction in the phase-change temperature.

[0022] In addition to a significant improvement in energy efficiency, there are other significant advantages. Due to the lower temperature and more direct heat transfer, surrounding areas are also heated less. Neighboring cold food or similar items are less affected, and unwanted heating of the surrounding area, for example, in summer, is avoided.

[0023] Within the scope of the invention, the warming bases must first be heated above their melting point, although this temperature is preferably below 100°C. From a user's perspective, the warming bases are still hot at this point, but a significant reduction in temperature can also fundamentally reduce the risk of injury. For example, if the warming bases are touched without gloves or similar protection, the risk of burns is lower, and even if an injury does occur, the severity of the burn is correspondingly lower.

[0024] According to the state of the art, it is fundamentally conceivable that warming bases with a transition temperature above 100°C and good insulation could overheat hot food, potentially causing liquids in the 100°C range to evaporate or begin to boil, which could severely damage the food. However, within the scope of the invention, such a deterioration can be avoided as described.

[0025] In conventional methods for handling hot food, the crockery items, particularly in the form of plates, are also preheated, where corresponding crockery items can be provided, for example, at a temperature of approximately 90°C. Within the scope of the invention, with appropriately heated warming bases, there is initially no significant temperature difference between the crockery item and the warming base, but at the phase transition the temperature is kept constant or essentially constant by the latent heat.

[0026] According to the present invention, the coldest areas of the warming base are generally located opposite the tableware, so that the phase-change material will initially form there in its solid state, advantageously providing improved insulation to the outside. It should be noted that the common organic phase-change materials, also known as wax, are relatively good thermal insulators in their solid state.

[0027] In contrast, with state-of-the-art hot-food systems, the opposite behavior can be observed in individual cases, which is disadvantageous. This is because the tableware, especially plates, is initially significantly colder than the warming base, and the phase change is generally designed at a higher temperature. The plate, which is then colder than the warming base according to the state of the art, can then potentially lead to wax, a solid phase change material, forming on the upper side of the warming base, thus creating thermal insulation in the wrong place and further exacerbating the efficiency deficits described above.

[0028] According to a preferred embodiment of the invention, the phase-change material has a latent heat storage capacity of more than 150 kJ / kg (kilojoules per kilogram), in particular more than 200 kJ / kg. For example, the latent heat storage capacity can be in a range between 200 kJ / kg and 260 kJ / kg.

[0029] One suitable material is the organic phase-change material RT 70 HC from Rubitherm Technologies GmbH, Berlin. This phase-change material exhibits a phase change at approximately 70 °C, providing a high latent heat storage capacity in the aforementioned range, particularly due to its comparatively high crystallinity.

[0030] In this context, the heat-retaining base can contain, for example, 100 g (grams) to 300 g of phase-change material. Due to the low losses, a smaller amount of heat is also consumed to keep the assigned item of cookware at the desired temperature.

[0031] As is well known, the hot food system can also include a cover.

[0032] The item of tableware is, in particular, a plate or a bowl, with corresponding items of tableware often being round and at least substantially rotationally symmetrical. However, the invention is not limited to such configurations. In principle, items of tableware with a different shape, for example, a rectangular or oval base, are also contemplated. Within the scope of the invention, the warming base and the item of tableware are geometrically coordinated with each other, at least to a certain extent.

[0033] According to the invention, the contact surface has a size of at least 30 cm 2 The contact surface can be continuous or divided into several areas.

[0034] According to a preferred embodiment of the invention, the contact surface has a size between 50 cm 2 and 250 cm 2 , especially between 100 cm 2 and 150 cm 2 on.

[0035] Additionally or alternatively, the contact surface can extend over 10% to 50%, in particular over 20% to 30%, of the base area covered by the warming base. It should be noted that, according to a preferred embodiment, the underside of the dish does not rest on the support contour against the top of the warming base. Rather, a gap remains there, which is particularly preferably greater than 0.5 mm. The contact surface is then spatially separated from the support contour.

[0036] Furthermore, it is also preferred if the contact surface does not extend to the outer edges of the dish or the warming base. Heating of an outer edge of the dish does not significantly contribute to keeping the hot food warm and instead leads to heat loss into the environment, thus causing undesirable temperature losses.

[0037] Furthermore, according to a preferred embodiment, a central free zone is provided between the warming base and the cookware part, where no contact occurs and a distance of more than 0.5 mm exists. The central free zone is farthest from the edges and thus can cool down less rapidly. Accordingly, less heat may be required there. The described central free zone allows for particularly good heat utilization, while also better preventing local overheating.

[0038] Starting from the central free area, the contact surface can be provided as at least one contact surface ring extending therearound. According to a preferred embodiment of the invention, the contact surface can also have a total of several, for example, two or three, contact surface rings, in which case recesses are arranged between the contact surface rings, which can, for example, accommodate circumferential support contours such as a circumferential dish base or the like in such a way that the latter does not have direct contact.

[0039] The warming base is preferably designed to be stackable. This means that the height of a stack is less than the sum of the individual heights of the elements it contains.

[0040] The warming bases usually have a raised outer edge, whereby the height of the individual warming base can be between 20 mm and 30 mm.

[0041] The area covered by the warming bases can be between 300 cm 2 and 750 cm 2 , especially between 400 cm 2 and 500 cm 2 be.

[0042] As previously described, the warming base and the crockery part are designed to complement each other. The crockery part is not supported on the support contour, as is the case with normal use by an end user, but rather on the contact surface opposite the warming base. Accordingly, it is preferably provided that a gap remains at the edge of the crockery part relative to the underlying warming base. This applies in particular to crockery parts in the form of plates, which are approximately the same size as the associated warming base.

[0043] On the other hand, by specifically matching the warming base and the cookware section, the described gap can also be kept comparatively small to reduce heat loss due to convection in the edge area. The gap can, for example, be between 0.2 mm and 5 mm, and in particular between 0.5 mm and 3 mm.

[0044] The tableware is preferably made of ceramic, especially porcelain.

[0045] The invention has been described above with reference to a hot food system consisting of a warming base and an associated crockery item. It is understood that in practice, an overall system will comprise a large number of warming bases and crockery items that are generally coordinated with one another in the manner described. The warming bases and crockery items are, of course, interchangeable. It is also understood that different types of crockery items, such as plates and bowls, can be used within the scope of the invention, but these must be coordinated with the warming base in the manner described.

[0046] The invention also relates to the warming base itself, which is provided for the previously described hot food system. The warming base has at least one circumferential recess on its upper side, formed opposite a dish support surface intended as a contact surface, with a depth of more than 3 mm for contact-free reception of a particularly circumferential support contour of the dish.

[0047] The invention further relates to a method for handling hot food using the previously described hot food system. The warming base is heated to a temperature between 70°C and 99°C, preferably between 70°C and 90°C, with the preferably preheated crockery being placed on the warming base before or after at least one hot food item is portioned onto the crockery item.

[0048] The invention is explained below with reference to the figures. They show: Fig. 1 to Fig. 3 alternative embodiments of the hot food system according to the invention, Fig. 4 a detailed view of a warming base of the hot food system.

[0049] The Fig. Figure 1 shows a hot food system according to the invention, comprising a warming base 2 comprising a heat storage material 1 and a crockery item 3, which has a support contour on the underside of the item in the form of an outer crockery base 4a and an inner crockery base 4b. The support contour is provided to support the crockery item 3 in the form of a plate during its normal use.

[0050] In the illustrated combination with the warming base 2, however, the crockery item 3 does not rest on the support contour. Rather, the underside of the crockery item and an upper side of the warming base 2 border directly outside the support contour and / or over a distance of less than 0.5 mm on a contact surface of at least 30 cm. 2 to each other.

[0051] In the illustrated embodiment, the contact surface is formed by three contact surface rings 5a, 5b, 5c, which extend concentrically around a central free area 6. The central free area 6 accommodates the inner dish base 4b without contact.

[0052] The outer dish base 4a is also received outside the third contact surface ring 5c ​​in an outer recess 7a, also without contact. The dish part 3, however, is supported on the contact surface—that is, in this embodiment, on the contact surface rings 5a, 5b, 5c—on the upper side of the warming base 2.

[0053] The aim is to achieve the largest possible contact area, although a small gap of less than 0.5 mm may remain at the contact surface due to design constraints. This ensures that support is provided at least over part of the contact surface.

[0054] At the contact surface, efficient heat transfer occurs through direct thermal contact, or essentially through direct thermal contact. If a minimal gap remains, it can at least be bridged relatively easily using thermal conduction.

[0055] Already in the Fig. 1 shows that the heat storage material 1 in the form of an organic phase-change material—also referred to as wax—is arranged in an interior space of the warming base 2 between cover layers 8. The cover layers 8 can be formed, for example, from stainless steel sheet, which, for example, has a thickness of 0.7 mm.

[0056] Due to the comparatively large contact area of ​​at least 30 cm 2 and preferably between 50 cm 2 and 250 cm 2 A good thermal coupling is achieved between the warming base 2 and the crockery part 3 arranged thereon. In order to achieve a desired target temperature with respect to the crockery part 3, a smaller temperature gradient is therefore necessary between the warming base 2 and the crockery part 3.

[0057] In particular, it is provided that the heat storage material 1 in the form of the phase-change material has a melting temperature between 50 °C and 90 °C, in particular between 63 °C and 83 °C, for example approximately 70 °C. During the phase transition, a latent heat storage capacity of the phase-change material can be more than 150 kJ / kg, in particular more than 200 kJ / kg. With a correspondingly high latent heat storage capacity, comparatively small amounts of phase-change material, for example, 100 g to 300 g, are sufficient for efficient use in a typical application.

[0058] For example, the warming base 2 and preferably also the crockery part 3 can have a diameter between 20 cm and 30 cm, for example about 24 cm.

[0059] As in the Fig. 2, the hot feed system can also have a cover 9 which, with an otherwise identical design, can be Fig. 1 is arranged above the crockery part 3 and the warming base 2.

[0060] The Fig. Finally, Figure 3 shows a stew bowl instead of a plate as the tableware part 3, which is arranged on the warming base 2. When compared with the Fig. 1 it is immediately apparent that the stew bowl as part of the tableware 3 has a smaller diameter. Fig. 3, the crockery part has an inner crockery foot 4b and an outer crockery foot 4a. However, the outer crockery foot 4a is received in an inner recess 7b between the second contact surface ring 5b and the third contact surface ring 5c ​​without contact.

[0061] The tableware pieces 3 shown in the figures are made of porcelain. The outer recess 7a and the inner recess 7b are adapted to the support contour of the tableware pieces 3 so that they can be accommodated without contact. In particular, the recesses 7a, 7b preferably have a depth of at least 3 mm relative to the support contour.

[0062] The Fig. 4 finally shows a detailed view of the warming base 2, wherein the two cover layers 8 formed from formed stainless steel sheet with the heat storage material 1 arranged between them can be seen particularly clearly. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2013 013 736 B4

[0003]

Claims

[1] Hot food system with a warming base (2) comprising a heat storage material (1) and a crockery part (3) which has a support contour on the underside of the crockery part, characterized by that the underside of the crockery part and an upper side of the warming base (2) outside the support contour directly and / or over a distance of less than 0.5 mm on a contact surface of at least 30 cm 2 adjacent to each other. [2] Hot food system according to claim 1, characterized by that the contact area has a size between 50 cm 2 and 250 cm 2 and / or that the contact surface extends over 10% to 50% of a base area covered by the warming base (2). (based on a plan view) [3] Hot food system according to claim 1 or 2, characterized by that the support contour is designed as at least one circumferential dish base (4a, 4b). [4] Hot food system according to one of claims 1 to 3, characterized by that the underside of the dishes on the support contour does not rest on the top of the warming base (2). [5] Hot food system according to one of claims 1 to 4, characterized by that the contact surface extends as at least one contact surface ring (5a, 5b, 5ct) around a central free area (6). [6] Hot food system according to one of claims 1 to 5, characterized by that a phase change material, in particular an organic phase change material, is provided as heat storage material (1), wherein the phase change material is arranged in an interior space of the heat-retaining lower part (2). [7] Hot food system according to claim 6; characterized bythat the phase change material has a melting temperature between 50°C and 90°C, in particular between 63°C and 83°C and / or a latent heat storage capacity of more than 150 kJ / kg, in particular more than 200 kJ / kg, during the phase transition. [8] Hot food system according to claim 6 or 7, characterized by that the warming base (2) contains 100 g to 300 g of phase change material. [9] Hot food system according to one of claims 1 to 8, characterized by that it comprises a cover (9). [10] Hot food system according to one of claims 1 to 9, characterized by that the item of tableware (3) is a plate or a bowl. [11] Hot food system according to one of claims 1 to 10, characterized bythat the warming base (2) is stackable and has an outer, raised edge, wherein a height of the warming base (2) is between 20 mm and 30 mm and wherein the warming base (2) has an area between 300 cm 2 and 750 cm 2 covers. [12] Hot food system according to one of claims 1 to 11, characterized by that the tableware part (3) is made of ceramic, in particular porcelain. [13] Warming base (2) for a hot food system according to one of claims 1 to 12, wherein at least one circumferential recess (7a, 7b) formed opposite a crockery part contact surface and having a depth of more than 3 mm is provided on an upper side for contact-free reception of a (circumferential) support contour of the crockery part (3). [14] Method for handling hot food with a hot food system according to one of claims 1 to 12, wherein the warming base (2) is heated to a temperature between 70° and 99°C, wherein the preferably preheated crockery part (3) is placed on the warming base (2) before or after at least one hot food is portioned onto the crockery part (3).

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