Stack heater

Abstract

The invention relates to a stack heating device for tableware items, in particular plates, and / or warming bases, comprising a housing (1), a receiving space (2) formed in the housing (1), at least one stack receptacle (3) arranged in the receiving space (2), and a heating device arranged in the housing (1). According to the invention, the heating device is formed by at least one infrared radiator (4).

Description

The invention relates to a stack heater for dishes, in particular plates, and / or keep-warm lower parts, having a housing, a receiving space formed in the housing, at least one stack receptacle arranged in the receiving space, and a heating device arranged in the housing.The present invention thus relates to the field of kitchen logistics and in particular to food distribution if food portions are to be provided in a larger quantity in a community or a gastronomy operation.Stacking devices for kitchen logistics are known in practice in many embodiments, for which purpose reference is made to the leaflet "Hupper-Stacking Devices" (https: / / www.hupper.com / media / pdf / 84 / eb / dc / built-in-stack operation instructions-Hupper.pdf, level 2019).Stacking devices are available in practice with and without a heating function, wherein the present invention relates specifically to a heated or heatable stacking device and thus a stacking heater.In a stack heater known from the cited leaflet, the heating device is designed as a heating body with a circulating air blower. A receiving space is formed in the housing, wherein two stack receptacles for plates or heat-retaining lower parts are arranged in the receiving space. The circulating air heating system heats up the entire interior substantially uniformly, wherein elements which are also accommodated in the stack receptacles, in particular in the form of plates and lower heat-retaining parts, are accordingly heated by the warm circulating air. A comparatively uniform heating can be achieved by the circulating air blower.In order to make possible the quick and reliable heating possible in the case of the usual dimensions of the stack heater and two stack receptacles, the output of the stack heater can be 3 kW, for example. Since the entire receiving space is heated by the circulating air blower, an inner wall of the housing is insulated from an outer wall of the housing with a thermal insulation. Due to the above-mentioned power, the stack heater must be connected to a separate power connection depending on the infrastructure. Even if the housing above the two stack receptacles is closable by hinged covers, considerable waste heat cannot be avoided. In addition to an energy efficiency requiring improvement, unpleasant environmental conditions can thus also result for operators.Stack heaters of the generic type are also known from CH 473 572 A and CH 430 087 A.According to CH 473 572 A, a tubular heater is arranged at a base of a receiving space, wherein here too the entire interior of a housing is heated up in order to heat up or keep warm plates and / or keep warm lower parts.According to CH 430 087 A, heating elements are provided which can be arranged directly on the stack receptacles. Even in the case of insulation, large heat losses can occur. Furthermore, the stack receptacles which are spatially separated from one another are also comparatively complicated to clean.It is an object of the present invention to provide a stack heater which has improved service properties.The invention and the object are achieved by a stack heater according to claim 1.Starting from a stack heater of the generic type, it is accordingly provided according to the invention that the heating device is formed by at least one infrared emitter.In the stack heater according to the invention, a fundamentally different heating principle is provided compared to the known designs. Instead of heating up the entire interior or at least one air gap to the tableware and / or keep-warm lower parts, according to the invention, heat is transferred by infrared radiation. Heating by infrared radiation results in the advantage that the air remaining in the receiving space is not heated directly, but at most indirectly.Even at a greater distance, the thermal energy can pass by infrared radiation from the heating device to the stack receptacle or to tableware and / or keep-warm lower parts arranged there. For example, a distance between 5 cm and 50 cm, in particular a distance between 10 cm and 30 cm, can be provided between the at least one infrared radiator and an adjacent stack of dishes, in particular plates, and / or keep-warm lower parts.According to a preferred embodiment of the invention, it is provided that an inner wall of the receiving space forms a type of reflector for the infrared radiation. The inner wall then reflects incident infrared radiation, while the infrared radiation is then largely absorbed or at least more strongly absorbed by accommodated tableware parts, in particular dishes, and / or keep warm lower parts.The inner wall can be formed, for example, from an aluminum layer as a reflector for the at least one infrared radiator, wherein porcelain as a typical material for dishes, in particular plates, and in particular stainless steel have a significantly greater absorption capacity for infrared radiation than the aluminum layer. Corresponding considerations apply not only to porcelain and stainless steel, but also to a number of other ceramic, vitreous, polymeric and metallic materials from which tableware can be formed.The infrared radiation can then be reflected on the inner wall multiple times and in particular without substantial losses, wherein only stacked tableware, in particular plates, or keep warm lower parts then absorb the infrared radiation and are thus heated up.It should be noted in principle that the at least one stack receptacle also has further components, such as a lifting frame and springs. While individual components of the stack receptacle can likewise be manufactured from a reflective material, other components, such as helical springs, can also be provided with a cover which reflects infrared radiation.The inner wall made of an aluminum layer and / or reflective covers made of aluminum can have a purity of at least 99%, for example, as a result of which a particularly good reflectivity with respect to infrared radiation is achieved.In principle, it is possible to configure the inner wall and / or covers to be particularly planar and smooth, so that they are also specular in the optical radiation region. With regard to the wavelength range of infrared radiation, however, such a particularly smooth surface is not absolutely necessary and at most leads to comparatively low increases in efficiency.A high purity is of particular importance for a good reflection of infrared radiation through the inner wall, but the surface can also be anodized to increase the resistance. As a result of the anodization, the formation of an oxide layer on aluminum, which also occurs naturally, is enhanced by anodic oxidation, resulting in improved protection against wear and corrosion. In this case, the anodizing does not have a significant effect on the reflectivity with respect to infrared radiation, although the resistance can be very significantly increased.In principle, various types of aluminum products are also suitable, taking into account the stated purity of preferably at least 99%. An aluminum sheet or an aluminum sheet with the material designation EN AW 5005 is suitable, for example. This is an alloy of aluminum and magnesium, with the magnesium content below about 1%. In contrast to other components, magnesium is deliberately added to the aluminum in a certain amount in order to achieve good functional properties. Components, on the other hand, are considered to be impurities, so that only maximum values are given for this purpose in the composition.EN AW 5005 is distinguished by very good corrosion resistance to atmospheric corrosion. Such good resistance is also of particular significance because, within the scope of the invention, easy cleaning of the stack heater is also advantageous.In this connection, according to a preferred embodiment of the invention, it is also provided that the at least one stack receptacle can be removed from the receiving space, preferably also without tools, so that the receiving space can then be cleaned particularly reliably and thoroughly.Especially with regard to the particularly high hygiene requirements in the field of food handling, particular advantages can thus also be obtained within the scope of the invention. This also applies in particular because the heating device is designed in the form of at least one infrared radiator in a particularly simple manner and, unlike in the case of the circulating air blower, there are no fans or the like.Since, within the scope of the invention, an active circulation of air within the receiving space is not necessary and is generally also not provided, contaminants can also be distributed less widely.As explained above, according to the invention, the dishes, in particular plates, and / or keep warm lower parts are heated or kept warm by infrared radiation, wherein the surrounding air is heated only secondarily. This also results in the fact that air remaining in the housing generally has a lower temperature than items of tableware received, in particular plates, and / or keep-warm lower parts, and moreover is also not circulated.Within the scope of the invention, therefore, significantly lower heat losses result from the warming-up of the entire housing or the outflow of warm or hot air, as compared with known stack heaters according to the prior art. The energy used is used substantially directly for heating or keeping warm the tableware, in particular plates, and / or keep warm lower parts, so that desired heating of the tableware, in particular plates, and / or keep warm lower parts can take place at significantly lower powers.An improved energy efficiency with regard to the heating of the tableware, in particular plates, and / or keep warm lower parts results in significantly lower electrical connection values for the stack heater with the same heating power with respect to the heating of the tableware, in particular plates, and / or keep warm lower parts. The stack heater can then also be used jointly in the context of the invention at a conventional power connection and / or with further electrical consumers.The improvement in the energy efficiency also results in a substantial cost saving, wherein the environment is also significantly less warmed up. Especially in the area of large kitchens with different heat sources, the working conditions can thereby be very considerably improved.Even if the infrared radiation can be distributed within the receiving space by reflection, it is provided according to a preferred embodiment of the invention that a plurality of infrared emitters are arranged around the at least one stack receptacle. For example, two infrared emitters can be provided at different positions or different sides of the stack receptacle, so that a particularly uniform radiation distribution can then also take place directly and via reflection.Suitable infrared emitters for heating purposes are known to the skilled person. According to a preferred embodiment, the at least one infrared emitter has a glass tube, in particular a straight glass tube and a heating coil accommodated therein. Corresponding infrared emitters are then straight and rod-shaped, wherein the at least one infrared emitter can then be vertically oriented with a longitudinal direction. The glass tube is preferably formed from quartz glass.Depending on the intended purpose and specific embodiment, for example, two to five infrared emitters can be provided as heating device.For a preferred embodiment of the stack heater with two stack receptacles, for example, three infrared emitters can be provided, which are then arranged at different locations of the interior space. The two stack receptacles are then preferably arranged at a distance from one another into the interior space, wherein the infrared rays can be distributed as freely as possible within the interior space. Apart from reflective covers, for example on springs of the stack receptacle, or the like, separate separating walls or the like are preferably dispensed with.The at least one infrared radiator can have a nominal power of between 250 W and 450 W, in particular between 300 W and 400 W.With a particularly preferred power of, for example, approximately 350 W, a total power of approximately 1 kW is then obtained in three infrared radiators, which total power is also sufficient to heat up a large amount of keep-warm lower parts in a comparatively short period of time. As already explained above, the power provided is then essentially used to specifically heat up or keep warm the tableware, in particular plates, and / or keep warm lower parts, wherein the air present in the receiving space is only heated secondarily and is also not actively converted.The at least one infrared radiator can have a color temperature in the range from 1600 K to 1900 K at the rated power. In particular, the color temperature is 1750 K + / - 100 K.In comparison with a known stack heater with a circulating air blower, movable, electrically driven parts are also dispensed with or largely dispensed with, so that noise emissions are additionally also avoided.Infrared emitters are distinguished in this context by a long service life and high robustness. Even if infrared emitters are subjected to a certain wear over the long term, a particularly simple replacement of the normally tubular infrared emitters can then be carried out if necessary. The at least one infrared emitter is in this case optionally covered by a grid or another protection within the receiving space, but otherwise exposed. The infrared emitter can also be provided with a standard socket which makes possible simple changeover by plugging in and / or latching and / or clamping.As explained above, the at least one infrared radiator can have a power of, for example, approximately 350 W and a color temperature of, for example, 1750 K + / - 100 K at the rated power. It is understood in principle that, within the scope of the invention, power regulation is also expedient in the heating device in order to provide different heating energy. In the case of a plurality of infrared emitters, individual ones can be switched off, for example, wherein a comparatively good energy distribution can then still be achieved by the reflection within the receiving space.Additionally or alternatively, the power of the individual infrared emitters can also be varied by suitable measures. For example, pulse width modulation is suitable, in which the power can be exactly predefined by the duty cycle, i.e. the on-off ratio.In order to achieve a uniform distribution of the infrared radiation, the preferably vertically oriented at least one infrared emitter can have a length between 300 mm and 800 mm, in particular between 400 mm and 700 mm. In particular, the at least one infrared emitter can extend over a major part of the height of the receiving space in order to achieve uniform illumination.While the inner wall is preferably formed from the aluminum layer as a reflector, an outer wall of the housing can be formed from stainless steel in order to achieve good resistance there. Even if the receiving space is heated to a lesser extent in comparison with embodiments from the prior art, insulation between the inner wall and the outer wall may be expedient for further optimization.According to a particularly preferred variant of the invention, the housing is arranged on rollers, so that the stack heater as a whole can be moved. However, the invention is not limited to such embodiments. Rather, the stack heater can also be provided for stationary use. A stationary use is considered, for example, when tableware, in particular dishes, and / or keep-warm lower parts are always required at the same position. In gastronomy operations, the stack heater can be arranged, for example, on a so-called Kellner pass, in order to provide warm or hot dishes there for erecting the dishes, it then being possible for the erected dishes to be taken over directly for output to a guest.In order to keep items of tableware, in particular plates, and / or keep warm lower parts ready at a desired temperature, a temperature sensor and / or a thermostat can be provided. However, it should be taken into account in the context of the invention that the air present in the receiving space is heated substantially only secondarily and thus does not allow reliable conclusions to be drawn about the actual temperature of the tableware and / or keep-warm lower parts. Against this background, a temperature sensor can also be arranged in a rear side of the inner wall in order to then determine the heating of the inner wall and thus to indirectly draw conclusions as to the temperature of the tableware and / or keep warm lower parts. Reference values for differently recorded elements can also be stored if necessary.The invention also relates to the stack heater described above, in which the at least one stack receptacle receives a stack having a plurality of dishes, in particular plates, or keep warm lower parts. The at least one stack receptacle can be provided, for example, for receiving 20 to 60, in particular 30 to 50, plates and / or lower heat-retaining parts. The plates are formed in particular from porcelain within the scope of the invention, although other configurations are also possible. For example, portion trays made of stainless steel are also known in the field of the sales of justicing completion institutions, which in the context of the invention are also referred to as tableware. The items of tableware can also be, for example, bowls, dishes, sub-trays, trays or the like. The invention is particularly suitable for dishes which can easily be stacked one above the other as a column, wherein each dish can be irradiated in sections, for example at its edge, by the infrared radiation.In principle, further tableware such as cups, cups or the like can also be provided. However, if these are arranged, for example, in baskets next to and above one another, then with inner tableware the keeping warm or the warming up can be impaired by shading effects. However, the basic mode of operation of the present invention can then also be utilized at least to a certain extent.Heat-retaining lower parts can preferably have, within the scope of the invention, a jacket made of stainless steel, wherein a wax or a comparable material is then provided as heat store within the jacket, which is subjected to a phase change between solid and liquid at a suitable temperature. A plateau then results during the warming up of the lower heat-retaining parts in the temperature profile, because supplied thermal energy at the temperature of the phase change is initially not used for further heating, but rather for melting the material. A corresponding plateau can generally also be detected by a temperature sensor and / or thermostat, wherein the occurrence of such a characteristic can then be advantageously used for controlling the heating device.In the described, frequently plate-shaped heat-retaining lower parts, it is then provided that the phase change material contained is melted during the removal from the stack heater, wherein then, during the transition into the solid state, a plateau of the temperature profile is advantageously provided again at an elevated temperature, with which tableware parts, in particular plates, and / or food, arranged on the heat-retaining lower part can be effectively kept warm.In a manner known per se, the housing can have a preferably closable removal opening on an upper side of the stack receptacle. For closing the removal opening, a hinged lid can be provided, for example. However, within the scope of the invention, the advantage is also obtained precisely in the open state that the air present in the receiving space is comparatively cold and is not actively circulated.The invention is explained below with reference to drawings. The following are shown: FIG. 1 shows a stack heater according to the invention in a perspective view, FIG. 2 shows the stack heater according to FIG. 1 in a side view, FIG. 3 shows the stack heater according to FIG. 1 in a view from above.The figures show a stack heater according to the invention for tableware, in particular plates, and / or keep-warm lower parts, having a housing 1, a receiving space 2 formed therein and two stack receptacles 3 arranged in the receiving space 2.The stack receptacles 3 are each provided to receive a stack of dishes, in particular plates, or keep-warm lower parts and have an otherwise customary and known design.Furthermore, the stack heater has a heating device arranged in the housing 1, which heating device is formed by three infrared emitters 4 in the exemplary embodiment shown. Two of the infrared emitters 4 are arranged centrally on one longitudinal side of the housing in housing corners and a further infrared emitter 4 is arranged centrally on the opposite longitudinal side. With respect to the individual stack receptacles 3, two of the infrared emitters 4 are thus arranged opposite one another.Apart from the stack receptacles 3 and the infrared emitters 4, the receptacle space 2 is substantially free and forms a reflector for the infrared radiation emitted by the infrared emitters 4. It is provided here that the receiving space 3 has an inner wall 5 made of an aluminum layer, wherein the aluminum layer has a purity of at least 99% and is anodized to improve the resistance. For example, an aluminum alloy EN AW 5005 is suitable, which is distinguished by a particularly good resistance, so that good cleaning of the receiving space 2 is also possible. For this purpose, the stack receptacles 3 can be removed from the housing 1 without tools.According to the invention, the tableware, in particular plates, or keep warm subparts, accommodated in the stack receptacles 3 are heated directly by the infrared radiation, while the air remaining in the receptacle space 2 is not subjected to any direct heating. In particular, no circulation of the air by means of a blower or the like is necessary either, and generally also not provided.In FIGS. 1 and 3, the housing 1 is opened on an upper side of one of the stack receptacles 3, wherein a hinged lid 6 is folded open. Even when the hinged lid 6 is open, there are only comparatively few heat losses, because the air contained in the receiving space 2 is colder than in a conventional stack heater and is also not subjected to any active circulation. This applies in particular if the opening on the upper side of the housing 1 is substantially formed by a stack of dishes, in particular plates, or a stack of keep-warm lower parts.Between the inner wall 5 formed from aluminum on the inner side of the receiving space 2 and an outer wall 7 of the housing 1, insulation is usually provided. Even if the receiving space 2 is heated to a lesser extent by the heating by means of infrared rays, corresponding insulation is nevertheless expedient.The three infrared emitters 4 are configured straight and rod-shaped according to the figures, wherein the infrared emitters 4 are vertically aligned with a longitudinal direction. The infrared emitters 4 have a conventional design with a glass tube and a heating coil accommodated therein. The glass tube is preferably formed from quartz glass.The housing 1 is arranged on rollers 8, so that the entire stack heating device can be moved. An electrical connecting line 9 is indicated in FIGS. 1 and 2.The three infrared emitters 4 typically have a length between 400 mm and 700 mm, wherein the infrared emitters 4 each have a rated power between 250 W and 450 W, in particular between 300 W and 400 W. The heating device formed by the three infrared rays 4 can have a total power of approximately 1000 W.The infrared emitters 3 have a color temperature of 1600 K to 1900 K, preferably 1750 K + / - 100 K, for example, at the rated power. In this case, a pulse width modulation is provided in particular for regulating the heating power, wherein the housing 1 can have a temperature sensor, not shown, and / or a thermostat.It can be seen in particular in FIG. 1 that switches 10 a, 10 bare provided on the outer side of the housing 1 in order to perform different settings. For example, it can be provided that different heating powers are set for plates on the one hand and keep warm lower parts on the other hand.At one of the switches 10b, fine adjustment of a temperature or the like can be performed by a rotary wheel.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedCH 473 572 A [0007,0008]CH 430 087 A [0007,0009]Cited Non-Patent LiteratureHupper Stackers" (https: / / www.hupper.com / media / pdf / 84 / eb / dc / built-in-stack operation instructions-Hupper.pdf, Level 2019

[0003]

Claims

A stack heater for dishes, in particular plates, and / or keep-warm lower parts, comprising a housing (1), a receiving space (2) formed in the housing (1), at least one stack receptacle (3) arranged in the receiving space (2) and a heating device arranged in the housing, characterised in that the heating device is formed by at least one infrared radiator (4).Stack heater according to Claim 1, characterized in that a plurality of infrared emitters (4) are arranged around the at least one stack receptacle (3).Stack heater according to one of the preceding claims, characterized in that the at least one infrared emitter (4) has a glass tube and a heating coil accommodated therein.Stack heater according to one of the preceding claims, characterized in that the at least one infrared emitter (4) is vertically aligned with a longitudinal direction.Stack heater according to one of the preceding claims, characterized in that the receiving space (2) has an inner wall (5) made of an aluminium layer as a reflector for the at least one infrared emitter (4).Stack heater according to claim 5, characterised in that the aluminium layer has a purity of at least 99% and is preferably anodized.Stack heater according to one of the preceding claims, characterized in that an outer wall (7) of the housing (1) is formed from stainless steel.Stack heater according to one of the preceding claims, characterized in that the housing (1) is arranged on rollers (8).Stack heater according to one of the preceding claims, characterized in that two to five infrared emitters (4) are provided.Stack heater according to one of the preceding claims, characterized in that the at least one infrared radiator (4) has a rated power of between 250 W and 450 W, in particular between 300 W and 400 W.Stack heater according to Claim 10, characterized in that the at least one infrared radiator (4) has a colour temperature of 1600 K to 1900 K at the rated power.Stack heater according to one of the preceding claims, characterized in that the housing (1) has a temperature sensor.Stack heater according to one of the preceding claims, characterized in that the housing (1) has a preferably closable removal opening on an upper side of the stack receptacle (3).Stack heater according to one of the preceding claims, characterized in that two stack receptacles (3) are provided next to one another in the receptacle space (2).Stack heater according to one of the preceding claims, characterized in that the at least one stack receptacle (3) receives a stack having a multiplicity of dishes, in particular plates, made of porcelain or stainless steel or heat-retaining lower parts having a jacket made of stainless steel.Stack heater according to one of the preceding claims, characterized in that the at least one stack receptacle (3) can be removed from the receptacle space (2).

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