Cooking appliance with sealing umbrella sleeve

Abstract

The invention relates to a cooking appliance, in particular a combination cooking appliance with steam cooking function and / or microwave cooking function and / or oven function, comprising a cooking appliance housing within which a space for the control electronics is formed, a cooking chamber, the so-called muffle, formed by cooking chamber walls, with an opening in a cooking chamber wall, with a cooking appliance light having a light guide which is led through the opening in the cooking appliance wall into the cooking chamber, with a shield sleeve which is arranged flush with the opening of the cooking chamber wall and which is fixed on the outside of the cooking chamber wall facing away from the cooking chamber and through which the light guide is led, with an annular gap which surrounds the light guide, with a sealing ring which closes the annular gap and seals the cooking chamber against the outside environment, wherein the annular gap is formed between the light guide and the shield sleeve.the sealing ring is located in the annular gap between the shield sleeve and the light guide, the sealing ring is located near the end of the shield sleeve facing away from the cooking chamber.

Description

[0001] The invention relates to a cooking appliance, in particular a combination cooking appliance with steam cooking function and / or microwave cooking function and / or oven function, comprising a cooking appliance housing within which a space for the control electronics is formed, a cooking chamber, the so-called muffle, which is formed by cooking chamber walls, with an opening in a cooking chamber wall, with a cooking appliance light which has a light guide which is led through the opening in the cooking appliance wall into the cooking chamber, with a shield sleeve which is arranged flush with the opening of the cooking chamber wall and which is fixed on the outside of the cooking chamber wall facing away from the cooking chamber and through which the light guide is led, with an annular gap which surrounds the light guide, with a sealing ring which closes the annular gap and seals the cooking chamber against the outside environment.

[0002] A cooking appliance of this type is disclosed, for example, in EP 4 033 861 A1 of the applicant. The microwave cooking appliance described there – a combination cooking appliance with different cooking technologies is not claimed there – has a shielding sleeve to prevent microwave radiation from escaping through the opening in the cooking chamber wall, through which the light guide of a cooking appliance lamp is introduced into the cooking chamber. A sealing ring is installed near the cooking chamber in an annular gap between the cooking chamber wall and the light guide.

[0003] There is a trend in the cooking appliance industry to combine several cooking techniques in so-called combination appliances. It has long been common to offer ovens that also include a microwave cooking function. Relatively new are combination ovens that combine microwave cooking with steam cooking, or even the functions of a conventional oven with steam cooking. There are also appliances—though currently only a few models—that combine both microwave and steam cooking functions in a conventional oven.

[0004] Combination ovens like these are generally high-quality appliances from manufacturers, which is why they often include additional convenience features. One such feature is pyrolytic cleaning, which involves intensely heating the oven cavity and walls to temperatures of up to 500 degrees Celsius.

[0005] Every cooking appliance has at least one interior light that illuminates the cooking chamber, allowing users to assess the cooking progress of food, for example. To allow light into the cooking chamber, an opening in the wall is essential. This opening contains a light guide – in conventional lighting technology, a cover glass; with LED lights, usually a light guide rod – through which the light is directed into the cooking chamber.

[0006] Each cooking technique has its own requirements for sealing such an opening.

[0007] In microwave ovens, shielding the microwave radiation is paramount. The otherwise closed muffle – the opening for inserting the food is disregarded here – prevents microwave radiation from escaping the cooking chamber. Therefore, an opening in the cooking chamber wall must be fitted with a shield, the so-called microwave trap. Often, grid or mesh structures are used for this purpose, but these impede light coupling. Alternatively, it is known to use a shielding sleeve arranged on the outside of the cooking chamber wall, as in the aforementioned EP 4 033 861 A1, the diameter of which is adapted to the wavelength of the microwave radiation in such a way that it prevents the radiation from escaping along the length of the sleeve.

[0008] Sealing the opening against escaping cooking fumes is relatively easy to achieve in microwave ovens, as they are only exposed to moderately high cooking chamber temperatures.

[0009] Ovens typically cook food at high temperatures. Cooking temperatures of 250 degrees Celsius and above are now commonplace. In the case of a pyrolytic cleaning function, the oven cavity is heated to approximately 500 degrees Celsius. When sealing the opening for the oven light, these high cooking temperatures play a crucial role in two respects. Firstly, significant heat loss occurs through an improperly sealed opening in the oven wall, which initially reduces energy efficiency. Secondly, heat loss through the oven wall opening leads to disproportionately high heating of the space between the oven wall and the appliance housing. The control electronics, which are sensitive to high temperatures, are located in this space. Therefore, sealing the oven wall opening is necessary to minimize heat loss.

[0010] On the other hand, a problem arises with ovens in that the sealing element must withstand the high cooking temperatures, which is why elastic sealing elements, such as those shown in EP 4 033 861 A1, are considered unsuitable. Therefore, EP 3 820 249 A1 proposes a graphite ring as a seal for such cases.

[0011] The steam cooking function not only results in moderately high temperatures in the cooking chamber. A steam cooker also operates with a certain amount of positive pressure within the cooking chamber. Furthermore, there is a high level of humidity in the cooking chamber. The seal for the wall opening through which light enters the cooking chamber must therefore withstand moderately high temperatures, but its primary function is to ensure a pressure- and moisture-proof seal. Any moisture escaping through the opening in the cooking chamber wall into the aforementioned space for the appliance's electronics would destroy them.

[0012] The object of the invention is to create a cooking appliance with a sealing arrangement that accommodates each of the cooking techniques, in order to either create a uniformly constructed muffle for each type of appliance with one and the same sealing arrangement, or to be structurally free in the combination of selected or all of the aforementioned cooking techniques in a combination appliance.

[0013] The problem is solved by an object having the features of claim 1, in particular its characterizing features, wherein the annular gap between the light guide and the shielding sleeve is formed, the sealing ring is arranged in the annular gap between the shielding sleeve and the light guide, and the sealing ring is arranged near the end of the shielding sleeve facing away from the cooking chamber.

[0014] The key advantage of the invention lies in the fact that—regardless of the cooking technology—a shielding sleeve is provided through which the light guide is fed into the cooking chamber. This shielding sleeve can serve to absorb microwave radiation when a microwave cooking function is used. A sealing ring is then provided for sealing the cooking chamber. This ring is positioned at the end of the shielding sleeve facing away from the cooking chamber. This ensures that the sealing ring is significantly spaced from the cooking chamber. Even at high temperatures, such as those encountered during pyrolytic oven cleaning, the temperatures at the end of the shielding sleeve facing away from the cooking chamber can be kept low. Therefore, the shielding sleeve is also advantageous for use in appliances without a microwave cooking function, as it allows the seal to be positioned away from the cooking chamber and thus protects the seal from excessive temperature stress.

[0015] For this purpose, the shielding sleeve may be significantly extended beyond the dimensions required for microwave shielding, in particular extending into the area housing the cooking appliance's electronics. This is especially conceivable if the light coupling occurs in a side wall of the cooking chamber, thus providing sufficient space to extend the shielding sleeve all the way to the top of the cooking appliance.

[0016] The spacing of the sealing area of ​​the shield sleeve, i.e., the area in which the sealing ring sits, from the cooking chamber allows the use of elastomers as sealing rings, with high-temperature-resistant elastomers, particularly high-temperature-resistant silicones, being a preferred material for the sealing ring. Such elastomers also allow, among other things, for a seal against overpressure, such as that found in steam cooking appliances.

[0017] However, it is also possible to form the sealing ring using a stuffing box packing or a fiberglass cord, thus using materials that also have an advantage in terms of temperature tolerance compared to high-temperature resistant elastomers.

[0018] The umbrella sleeve can be permanently attached to the oven wall, for example by welding. However, it is not uncommon and advantageous for the invention if the umbrella sleeve forms a mounting flange through which at least one mounting pin is inserted, by means of which the umbrella sleeve is fixed to the oven wall.

[0019] It is advantageous if the shield sleeve is thermally decoupled from the cooking chamber wall. This prevents the shield sleeve, which is usually made of a metallic material, from heating up significantly due to the cooking chamber wall being exposed to the cooking temperature. This considerably helps to keep the sealing area of ​​the shield sleeve facing away from the cooking chamber, especially for elastic sealing elements, at a low temperature.

[0020] Thermal insulation is preferably achieved by placing a thermally insulating component, such as a fiberglass mat, a ceramic, a micanite disc or a graphite layer, between the mounting flange of the screen sleeve and the cooking chamber wall.

[0021] The invention provides that a fastening element is mounted on the fastening pin, which holds the fastening flange between itself and the oven wall. Sufficient pressure can be applied to the thermally insulating component by means of the fastening element to prevent steam from escaping between the oven wall, the thermally insulating component, and the fastening flange.

[0022] A so-called fastening part can, for example, be a nut that is screwed onto a fastening pin designed as a threaded bolt in order to hold the umbrella sleeve to the oven wall and, if necessary, also to apply the aforementioned pressure force.

[0023] However, it is also conceivable that the mounting pin is equipped with a pressure spring that exerts pressure on the mounting flange to ensure a defined fit against the oven wall. In this case, the pressure spring would be considered a mounting component.

[0024] Thermal insulation can be improved by placing a thermally insulating component, such as a fiberglass mat, a ceramic, a micanite disc or a graphite layer, between the mounting part and the mounting flange.

[0025] Should an electrical connection between the shielding sleeve and the oven wall be necessary, for example, to reliably absorb microwave radiation, this can be achieved using a suitable electrical conductor between the shielding sleeve and the oven wall. This can be accomplished by a direct connection from the shielding sleeve to the oven wall, which, in the case of thermal insulation, may only be present in certain areas. However, it is also possible to use electrical conductors, such as cables, or to rely on spring elements that ensure sufficient contact pressure between the shielding sleeve and the oven wall during installation.

[0026] A particularly preferred embodiment of the invention is one in which the end of the umbrella sleeve facing away from the cooking chamber is arranged in a cooling air stream.

[0027] This solution further reduces the thermal stress on the sealing area of ​​the shield sleeve.

[0028] It is a considerable advantage if the cooling airflow is the cooling airflow that cools the device electronics.

[0029] A better understanding of the invention and its further advantages can be found in the following description of an exemplary embodiment. It shows: Fig. 1 A schematic representation of the installation situation of a cooking appliance light of the first embodiment on a cooking chamber wall in view of the inner surface of the cooking chamber wall, Fig. 2 the representation according Fig. 1 View of the outer surface of the cooking chamber wall, Fig. 3 an exploded view of the illustration according to Fig. 1, Fig. 4 a longitudinal section through the cooking appliance light arranged on a cooking chamber wall Fig. 1, Fig. 5 an exploded view of the in Fig. 4. The facts shown, Fig. 6 a schematic representation of a cooking appliance according to the invention with the in Fig. 1 to 5 or the one in the Fig. 7 to 10 shown installation situations of a cooking appliance light. Fig. 7 A schematic representation of the installation situation of a cooking appliance light of the second embodiment on a cooking chamber wall in view of the inner surface of the cooking chamber wall, Fig. 8 the representation according Fig. 7 in view of the outer surface of the cooking chamber wall, Fig. 9 an exploded view of the illustration according to Fig. 7, Fig. 10 a longitudinal section through the cooking appliance light arranged on a cooking chamber wall Fig. 7, Fig. 11 the representation according Fig. 7 with sealing ring in alternative arrangement.

[0030] In the figures, a cooking appliance according to the invention is provided with the reference numeral 10.

[0031] The cooking appliance 10 is schematically represented in its entirety in Fig. Figure 6 shows the cooking appliance. It comprises a cooking appliance housing 11, which forms the outer, visible boundary of the cooking appliance 10 and within which all components of the cooking appliance 10 are arranged. The cooking appliance housing 11 has a cooking appliance door 12, through which a cooking chamber 13 is accessible. In the cooking chamber 13, a food item 15 to be cooked, here poultry as an example, is arranged on a food carrier 14. Above the cooking chamber 13, a control panel 16 is shown, behind which the control electronics of the cooking appliance 10 are arranged.

[0032] The cooking chamber 13 is enclosed by cooking chamber walls 17, which form the so-called muffle 18.

[0033] In Fig. Figure 6 shows the cooking appliance 10 partially broken open to show an exemplary, but not mandatory in its orientation and arrangement, installation position of a cooking appliance light 19 in the upper cooking chamber wall 17.

[0034] Fig. Figure 1 shows a schematic partial view of the installation situation of the oven light 19 in the upper oven wall 17, near the control panel. The inner side I of the oven wall 17, facing the oven, is visible, and it has an opening 20. Around the opening 20 are the heads 21 of fastening pins 22, by means of which a fastening flange 23 of a shade sleeve 24 is secured to the outer side A of the oven wall, facing away from the oven 13. The use of fastening pins 22 is optional and not essential for the invention. The shade sleeve 24, or its fastening flange 23, can also be connected to the oven wall 17, for example, by welding.

[0035] The cooking appliance light 19 has a rod-shaped light guide 25, which is fixed in a retaining part 26 of the cooking appliance light 19. This light guide 25 is led through the shade sleeve 24 into the area of ​​the opening 20 in the cooking chamber wall 17 and can thus supply light into the cooking chamber 13.

[0036] Fig. 2 shows one to Fig. 1. Analogous representation, although the perspective has been changed. The viewer is looking at the outer side A, i.e., the side of the cooking chamber wall 17 facing away from the cooking chamber 13. Here it can be seen that the fastening pins 22 are designed as screw bolts, onto which fastening parts 27 in the form of nuts have been screwed. These hold the fastening flange 23 between themselves and the cooking chamber wall 17.

[0037] Fig. Figure 2 further shows that the inner diameter of the shield sleeve 24 is larger than the outer diameter of the light guide 25 - which also applies to the diameter ratio of opening 20 and light guide 25 - so that an annular gap R is formed between the light guide 25 and the sleeve wall.

[0038] Fig. Figure 3 shows an exploded view of the arrangement of the cooking appliance light 19 and the cooking chamber wall 17 in Fig. 1. The following can be gleaned from this: The oven light 19 has a heat sink 28 on which a circuit board 29 is mounted by two mounting means 30. At least one LED (not labeled) is mounted on the circuit board 29, so that the circuit board 29 serves as the light source for the oven light 19. The circuit board also has unlabeled terminal blocks to which connecting conductors 31 are attached to supply the oven light with electricity.

[0039] A coupling cup 32, together with a swivel frame 33, forms the retaining part 26, by means of which the cooking appliance light 19 is fixed to a suitable support in the cooking appliance 10. The coupling cup 32 has a receiving sleeve 34 in which the light guide 25 is secured by means of a retaining spring 35. The light emitted by the LED enters the light guide 25 through an opening in the coupling cup 32 (not shown) and is then directed by it – as it Fig. 1 shows that it is fed into cooking chamber 17.

[0040] The umbrella sleeve 24 has, in addition to the sleeve body 36, a mounting flange 23, which is fixed at the end of the sleeve body 36 closest to the cooking chamber 13. The mounting flange is pierced by bores 37, through which the mounting pins 22 penetrate to fix the umbrella sleeve 24 to the cooking chamber wall 17. Fig. Figure 3 shows a thermally insulating component 38 in the form of an insulating ring. This insulating ring 38 has an opening 39 for the light guide 25.

[0041] In addition to the mounting flange 23, the insulating ring 38 and the cooking chamber wall 17 also have bores 37 for the passage of the mounting pins 22. These bores 37 are arranged in alignment with each other to allow unimpeded passage of the mounting pins 22.

[0042] The opening 20, the cooking chamber 17, the passage 39 of the insulating ring 38 and the passage channel 40 formed by the sleeve for the light guide 25 are also arranged in alignment with each other.

[0043] Fig. Figure 3 shows three further thermally insulating components 41 in the form of insulating discs. Furthermore, in Fig. 3 shows a sealing ring 42 which is placed around the light guide 25.

[0044] Fig. Figure 5 shows a vertical section in exploded view through the arrangement of the cooking chamber wall 17 and the cooking appliance light 19, whereby only the light guide 25 of the cooking appliance light 19 is shown for the purpose of a better overview.

[0045] Fig. Figure 5 shows how the components essential for the invention are arranged in relation to each other.

[0046] The opening 20 of the cooking chamber wall 17, the passage channel 40 of the sealing sleeve 24, the sealing ring 42, and the light guide 25 are aligned with each other. The optional insulating ring 38, if used, is also positioned in alignment with its passage 39. If the components are now assembled as described in Fig. As shown in Figure 4, the free end of the light guide rod 25, which is located away from the heat sink 28, is inserted in the area of ​​the opening 20 of the cooking chamber wall 17, in the present example according to Fig. 4. The light guide 25 passes through the opening 20 and its free end even reaches into the cooking chamber 13. In this way, it is possible to supply light to the cooking chamber 13.

[0047] The optical fiber 25 penetrates the sleeve body 36 of the shielding sleeve 24. In the case of the thermal insulation component 38 used here, in the form of the insulating ring 38, the optical fiber 25 also penetrates the opening 39. The sealing ring 42 surrounds the optical fiber 25 and is located in an end region of the shielding sleeve 24 facing away from the cooking chamber 13. The sealing ring 42 closes the annular gap R, so that the optical fiber 25 is sealed against the inner circumferential wall of the shielding sleeve 24.

[0048] In this way, the sealing ring 42 is sufficiently far removed from the area of ​​high temperature stress, namely the cooking chamber 13, so that even less temperature-stable materials can be used for the sealing ring 42. Elastomers that can seal particularly effectively against moisture and overpressure are especially preferred. This is of great importance when using steam cooking functions in cooking appliances 10.

[0049] To further improve thermal insulation, the invention proposes – as shown in the figures and in particular – Fig. Figure 4 shows the arrangement of an insulating ring 38 as a thermally insulating component between the mounting flange 23 of the shield sleeve 24 and the oven wall 17. This is preferably a thermally highly stable material, such as a ceramic, fiberglass, or similar material. In this way, heat transfer from the oven wall 17 to the shield sleeve 24 is significantly reduced, thereby also considerably reducing the temperature stress on a sealing ring 24.

[0050] Fig. 4 shows in conjunction with Fig. Figure 5, as well as the other illustrations, shows that heat dissipation to the shield sleeve 24 can be further reduced if insulating washers 41 are arranged between the mounting part 27, which rests on the mounting pins 22, and the mounting flange 23. In this way, heat transfer to the mounting flange 23 via the mounting pins 22 is significantly reduced. Depending on the specific installation situation, this can be of considerable advantage, but it is not essential for the invention.

[0051] What Fig. Figure 4 also shows that the insulating ring 38, i.e., the thermally insulating component between the mounting flange 23 and the cooking chamber wall 17, can be adapted as precisely as possible to the outer diameter of the light guide rod 25 or, in the case of more flexible materials, even manufactured with a slight undersize. In this way, the annular gap R in the area near the opening 20 of the cooking chamber wall 17 is significantly reduced or even completely closed. This reduces or even prevents warm air from entering the annular gap R from the cooking chamber, which in turn reduces heat dissipation from the cooking chamber 13 to the shield sleeve 24.

[0052] In this way, a way is created to reliably seal the opening 20 in the cooking chamber wall 17, required for the introduction of light from a cooking appliance light 19, for all common cooking methods (oven, steam cooking, microwave). Consequently, only a universal sealing arrangement is required, whereby, advantageously, elastomers can be used as the sealing ring 42. This not only makes it possible, for the first time, to produce a combination cooking appliance with all three cooking techniques, but also, in particular, to use a standardized oven cavity for any type of cooking appliance, thus reducing design and production costs.

[0053] In addition, the figures make it very easy to imagine that the shield sleeve 24, with its end near the light and containing the sealing ring 42, can be drawn into an area surrounded by cooling air, or that a partial flow of cooling air can be directed to that very end of the shield sleeve 24 in order to further reduce the thermal stress on the end containing the seal 42.

[0054] The invention also discloses a number of optional and supplementary features that can be used if the structural arrangement of the cooking appliance light 9 results in the arrangement of the sealing ring 42, spaced apart from the cooking chamber 13, being insufficient on its own. Such a structural arrangement may be present, for example, if the light coupling is not as described in Fig. 6 is sketched above the upper oven wall 17, near the control panel 16, but light coupling is provided in one of the side walls or even in the rear wall.

[0055] The Fig. Figures 7 to 10 show a second embodiment of the invention, which is similar to the first embodiment in most aspects; therefore, what has been said about the first embodiment largely applies to the second, in the Fig. The embodiment shown in figures 7 to 10 should be read.

[0056] In particular, the second embodiment also shows in Fig. 7 a cooking appliance light 19, the light guide rod 25 of which is inserted into a cooking chamber through a shade sleeve 24, penetrating an opening 20 in the cooking chamber wall 17. The shade sleeve 24 is secured with fastening pins 22, the heads 21 of which are in Fig. 7 can be seen, and the fastening parts 27 arranged thereon are fixed on the outside A of the cooking chamber wall 17 (see also Fig. 8) For this purpose, the umbrella sleeve 24 has a mounting flange 23.

[0057] The in Fig. The exploded view shown in Figure 9 depicts the cooking appliance light 19 in its heat sink 28, on which a circuit board 29 is secured by fastening means 30 – here, snap hooks. In this embodiment, the coupling cup 32 with its receiving sleeve 34 for the light guide rod 25 is designed without a swivel frame and is attached directly to the cooking appliance 10 to secure the cooking appliance light 19.

[0058] Also shown is the sealing ring 42, which, however, is arranged differently in the present second embodiment compared to the first embodiment, as will be discussed later. The shield sleeve 24 with its mounting flange 23, which is designed to rest on the schematically depicted oven wall 17, is also shown. Further details can be found in the description of the first embodiment.

[0059] The essential difference between the second embodiment of the invention and the one described in the Fig. The first embodiment described in 1 to 5 lies in the arrangement and design of the sealing ring 42, which is particularly evident in Fig. 10 can be seen.

[0060] The sealing ring 42 has an annular groove 43 formed between a sealing lip 44 and an annular wall 45.

[0061] The end of the ring wall 45 of the receiving sleeve 34, which is free towards the cooking chamber wall 17, is seated in the annular groove 43, with the sealing lip 44 being arranged in the annular gap R between the receiving sleeve 34 and the light guide 25. A sealing end face 46 of the sealing ring 42 points towards the shielding sleeve 24 and rests at least on its free end, which points away from the cooking chamber wall 17. However, an arrangement in which the sealing lip 44 slightly overlaps the free end of the shielding sleeve 24 is preferred.

[0062] It is easy to imagine that the sealing ring 42 according to Fig. The sealing ring 42 can be arranged rotated by 180°. The annular groove 43 of the sealing ring 42 then receives the free end of the shielding sleeve 24, with the sealing lip 44 then sitting in the annular space R between the shielding sleeve 24 and the light guide 25. In this way, regardless of the chosen arrangement of the sealing ring 42, a seal of the cooking chamber 13 against its external environment is ensured in an area with lower temperature exposure. This is in Fig. 11 shown.

[0063] As mentioned at the outset, it is conceivable to use a stuffing box packing or a fiberglass cord instead of the elastomer sealing ring 42, which in any case represents a preferred embodiment of the invention. In both cases, it is possible to create a sufficiently good seal, even for steam cookers, by compressing the sealing material if, despite all efforts, the temperature load in the area of ​​the shield sleeve 24 located away from the cooking chamber 13 is too high for the use of elastomer seals. REFERENCE MARK LIST 10 Cooking appliance 11 Cooking appliance housings 12 Oven door 13 Cooking chamber 14 cooking trays 15 groceries 16 Control panel 17 Oven wall 18 Muffles 19 Cooking appliance light 20 openings out of 17 21 heads 22 Fastening pin 23 Mounting flange 24 Umbrella sleeve 25 fiber optic cables 26 Holding part 27 Fastening part 28 heat sinks 29 Circuit board 30 Fasteners 31 connection conductors 32 coupling pot 33 swivel frames 34 Mounting sleeve 35 Retaining spring 36 shell bodies 37 bore 38 Thermally insulating component / insulation 39 Passage 40 Passage channel 41 Thermally insulating component / insulating disc 42 Sealing ring 43 Ring groove 44 Sealing lip 45 Ring wall 46 Sealing face Inside A Outside R annular gap QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] EP 4 033 861 A1 [0002, 0007, 0010] EP 3 820 249 A1

[0010]

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