Cooking chamber door for a cooking appliance and cooking appliance

Abstract

Cooking chamber door (18) for a cooking appliance (10) with a microwave unit (16), comprising at least one inner pane (22), one outer pane (24) and a perforated plate (26), wherein the perforated plate (26) is arranged between the inner pane (22) and the outer pane (24), wherein the perforated plate (26) is spaced from the inner pane (22) and / or outer pane (24) such that an expansion space (38) is provided for the perforated plate (26), and wherein the perforated plate (26) has an embossing (40), characterized in that the embossing (40) on the inner pane (22) results in at least one temperature hotspot (44).

Description

[0001] The invention relates to a cooking chamber door for a cooking appliance with a microwave unit, comprising at least one inner pane, one outer pane, and a perforated plate, wherein the perforated plate is arranged between the inner pane and the outer pane. Furthermore, the invention relates to a cooking appliance for cooking food, comprising a cooking chamber, a microwave unit, and a cooking chamber door.

[0002] A perforated plate is used in the cooking chamber doors of a cooking appliance with a microwave unit to prevent microwave radiation from escaping from the cooking appliance. In double-glazed cooking chamber doors, the perforated plate is positioned between an inner and outer pane, with both the inner and outer panes being made of tempered soda-lime glass.

[0003] The outer pane of a cooking chamber door is the glass pane facing the cooking appliance's surroundings. If the cooking chamber door comprises more than two panes of glass, for example, triple glazing, multiple inner panes are provided. The multiple inner panes are then also referred to as the intermediate pane(s) and the cooking chamber pane, with the cooking chamber pane facing (directly) the cooking chamber. The perforated sheet is usually located between the cooking chamber pane and the subsequent middle pane if the cooking chamber door has more than two panes of glass.

[0004] At high temperatures, the perforated sheet expands, causing it to come into contact with one of the adjacent panes. This can leave marks on the glass, obscuring the view into the cooking chamber. Accidental contact between the perforated sheet and one of the panes can also cause damage to that pane due to the mechanical stress caused by the accidental contact.

[0005] Furthermore, at temperatures above 280°C, the tempering in the soda-lime glass of the inner and outer panes is reduced, making the glass pane more prone to cracking if it comes into contact with cold liquids, for example. To prevent this, borosilicate glass can be used, which is less temperature-sensitive and therefore does not heat up as quickly. However, the use of borosilicate glass is expensive, especially compared to soda-lime glass, which also increases the price of the cooking appliances.

[0006] From DE 102 56 624 A1 a microwave oven is known whose door has a viewing window and additionally a perforated plate which is part of a microwave trap.

[0007] The object of the invention is to provide a cooking chamber door for a cooking appliance which is a cheap and simple alternative to borosilicate glass and guarantees a high level of durability.

[0008] This object is achieved according to the invention by a cooking chamber door for a cooking appliance with a microwave unit, wherein the cooking chamber door comprises at least one inner pane, one outer pane, and a perforated plate. The perforated plate is arranged between the inner pane and the outer pane, with the perforated plate being spaced apart from the inner pane and / or outer pane, thereby providing expansion space for the perforated plate. Furthermore, the perforated plate has an embossing that results in at least one temperature hotspot on the inner pane.

[0009] The invention therefore provides that the perforated sheet is placed between the at least one inner pane and the outer pane in such a way that, despite possible temperature-induced expansion of the perforated sheet, no contact occurs between the perforated sheet and the adjacent pane, in particular the inner pane. In principle, expansion of the perforated sheet is counteracted by the perforated sheet comprising an embossing that stabilizes the perforated sheet or reduces the expansion of the perforated sheet so that no contact can occur. Such embossing of the perforated sheet is simple and inexpensive to manufacture, so that excessive thermal expansion of the perforated sheet and consequently contact between the perforated sheet and the adjacent pane can be avoided without major expenditure. The embossing is therefore a stiffening embossing.

[0010] The embossing allows the hotspot to be created in a targeted manner, as the reflected microwaves are directed accordingly, so that the service life of the cooking chamber door, especially that of the inner pane, is not affected.

[0011] As already explained above, the cooking chamber door can have two or more panes, whereby in the case of more than two panes, one cooking chamber pane and one or more intermediate panes are provided.

[0012] If more than two panes are provided, the perforated sheet is preferably arranged between a cooking chamber pane and an intermediate pane directly adjacent to the cooking chamber pane to achieve the best possible microwave shielding. A heat-reflecting layer can also be provided on one of the intermediate panes. If a double pane is provided, the perforated sheet is arranged between the inner pane, which serves as the cooking chamber pane, and the outer pane.

[0013] According to one embodiment, the embossing is provided on the side of the perforated sheet facing the inner pane. The embossing therefore curves towards the outer pane in the area of ​​the embossing. In other words, the pressure for the embossing is exerted on the side of the perforated sheet facing the inner pane. This results in a compact design, as the perforated sheet already has a frame-like edge all the way around for assembly purposes and projects towards the outer pane. The embossing therefore extends into the space already provided. In addition, the outer pane is less sensitive due to its distance from the cooking chamber and heats up more slowly. Thus, the glass temperature of the outer pane is lower than that of the inner pane, so that contact with cold liquids poses a lower risk of the glass pane shattering.

[0014] Furthermore, the embossing can be designed to focus the microwaves reflected from the perforated sheet along a bending line onto the inner pane. The embossing can therefore create a targeted direction of the reflected microwaves, so that the majority of the energy is absorbed along the bending line of the inner pane, thus preventing damage to the inner pane. This is because the embossing can direct the microwaves to specific areas, creating targeted hotspots on the inner pane, particularly in areas not exposed to cool liquids. Furthermore, other components in the area of ​​the cooking chamber door that are sensitive to temperatures can be protected in this way.

[0015] According to a further embodiment, the embossing is applied circumferentially to the perforated sheet. This provides the best possible stiffness for the perforated sheet, so that unwanted deformation of the perforated sheet due to expansion at high temperatures can be almost completely avoided.

[0016] According to a further embodiment, the embossing is designed such that the perforated sheet has a surface within the circumferential embossing that is parallel to a base surface of the perforated sheet. Thus, the distance between the perforated sheet and the inner pane remains unchanged, allowing the installation space required for the cooking chamber door to be kept as small as possible. The embossing stiffens the surface, thus counteracting expansion due to the high temperatures in the cooking chamber and the energy of the microwaves impinging on the perforated sheet.

[0017] Preferably, the perforated sheet is U- or V-shaped. These embossings are easy to produce, resulting in minimal additional costs.

[0018] As an alternative to U- or V-shaped embossing, which corresponds to semicircular and triangular beads, box or trapezoidal beads can also be used.

[0019] The perforated sheet can therefore have a peripheral edge and a flat base, with holes provided in the base. The embossing is formed between the peripheral edge and the base. Thus, the embossing can be formed in an area that has holes and / or in an area that does not have holes. If the embossing is formed in an area that has holes, the embossing process is easier to perform, as less force is required to emboss the perforated sheet. Embossing in an area that does not have holes, on the other hand, is more stable.

[0020] Furthermore, the object is achieved according to the invention by a cooking appliance for cooking food. The cooking appliance comprises a cooking chamber, a microwave unit and a cooking chamber door comprising at least one inner pane, an outer pane and a perforated plate, wherein the perforated plate is arranged between the inner pane and the outer pane. The perforated plate of the cooking chamber door is at a distance from the inner pane and / or a distance from the outer pane, such that an expansion space for the perforated plate is provided between the inner pane and the perforated plate and / or between the outer pane and the perforated plate. At least one spacer is arranged at least between the inner pane and the perforated plate and / or between the outer pane and the perforated plate. The inner pane is in particular the cooking chamber pane, i.e. the pane which directly borders the cooking chamber.The at least one spacer holds the perforated sheet directly in its central position between the inner and outer panes, particularly with respect to the inner pane. This ensures that even if the perforated sheet expands, no contact can occur with the inner or outer pane. The spacer essentially prevents any marks left by the perforated sheet on the inner or outer pane and generally prevents contact with the inner or outer pane. Furthermore, such spacers are quick and easy to implement.

[0021] In particular, only one expansion space is provided, i.e., either an expansion space between the inner pane and the perforated sheet or an expansion space between the perforated sheet and the outer pane. In this case, the at least one spacer is also provided either only between the inner pane and the perforated sheet or only between the perforated sheet and the outer pane.

[0022] The spacers are preferably made of Teflon, so they don't leave marks on the panes. Furthermore, Teflon is a microwave-safe material that's also suitable for use at high temperatures, i.e., temperatures above 300°C.

[0023] According to one embodiment, at least two spacers are provided, in particular more than two spacers, evenly distributed over the surface of the perforated sheet, for example, four spacers. This ensures that the desired distance is maintained at every position of the perforated sheet and minimizes possible temperature-related expansion of the perforated sheet.

[0024] Further advantages and features of the invention will become apparent from the following description and the drawings, to which reference is made. In the drawings: - Fig. 1 a schematic representation of a cooking appliance according to the invention; - Fig. 2 a schematic view of a cooking chamber door according to the invention; - Fig. 3 a schematic view of a cooking chamber door in Fig. 2 perforated sheets used; - Fig. 4 a schematic side view of the perforated sheet from Fig. 3; - Fig. 5 a schematic representation of the energy density in the area of ​​an embossing of the perforated sheet; and - Fig. 6 a schematic representation of a cooking chamber door with spacers.

[0025] In Fig. 1 schematically shows a cooking appliance 10 which comprises a cooking chamber 14 enclosed by a housing 12 and a microwave unit 16.

[0026] In addition, the cooking appliance 10 has a cooking chamber door 18 with which access to the cooking chamber 14 is possible by opening or closing the cooking chamber door 18.

[0027] The cooking chamber door 18 of the cooking appliance 10, which is Fig. 2, is provided with a window 20 through which the cooking chamber 14 can be viewed from the outside. The window 20 consists of at least two transparent glass panes, in particular an inner pane 22 and an outer pane 24.

[0028] A perforated plate 26 is arranged between the inner pane 22 and the outer pane 24. The perforated plate 26 is thus arranged in the window 20.

[0029] In cooking appliances 10 with more than two glass panes, the pane facing the surroundings is referred to as the outer pane 24, while the pane facing the cooking chamber 14 can be referred to as the cooking chamber pane. Any panes located between the cooking chamber pane and the outer pane 24 can be referred to as center or intermediate panes. Both the cooking chamber pane and the center or intermediate panes represent inner panes 22.

[0030] Generally, in cooking appliances 10 with more than two glass panes, the perforated plate 26 is located between the inner pane 22, which serves as the cooking chamber pane, and the outer pane 24. Specifically, the perforated plate 26 is located between the cooking chamber pane and the adjacent middle or intermediate pane. In the case of a double pane, the perforated plate 26 is arranged between the inner pane 22, which serves as the cooking chamber pane, and the outer pane 24.

[0031] The cooking chamber door 18 has a frame 28 which supports the individual glass panes 22, 24 and the perforated sheet 26.

[0032] As in Fig. 3, the perforated plate 26 has a peripheral edge 30 with teeth 32 extending therefrom, which are spaced apart from one another, so that the resulting tooth structure functions as a microwave trap.

[0033] The peripheral edge 30 surrounds a base area 34, which has a plurality of holes 36, of which Fig. 3, only some are shown schematically. The exact number and shape of the holes 36 depends on the cooking appliance 10.

[0034] Since the perforated plate 26 is provided as a microwave shield in the cooking chamber door 18 to prevent the microwave radiation from escaping from the housing 12 of the cooking appliance 10 and still allow the operator to look into the cooking chamber 14, the holes 36 have a diameter that ensures that the perforated plate 26 functions as a microwave trap.

[0035] The base surface 34 of the perforated plate 26 is located in a plane parallel to the circumferential edge 30. The base surface 34 is closer to the inner pane 22 than the circumferential edge 30, which is closer to the outer pane 24.

[0036] Additionally, in the embodiment shown, a distance is provided between the perforated plate 26 and the inner pane 22, which corresponds to an expansion space 38 for the perforated plate 26. Alternatively or additionally, an expansion space can also be provided between the perforated plate 26 and the outer pane 24.

[0037] In order to stiffen the base surface 34 and counteract possible expansion due to high temperatures, the perforated sheet 26 also has an embossing 40.

[0038] The embossing 40 is preferably applied to the side of the perforated sheet 26 facing the inner pane 22. This means that the curvature created by the embossing 40 extends in the direction of the outer pane 24, wherein the embossing 40 does not exceed the plane of the peripheral edge 30, as can be seen from Fig. 4. This results in a compact design despite the embossing 40.

[0039] As in Fig. As can be seen in Figure 3, the embossing 40 can be formed circumferentially on the perforated sheet 26. This achieves the highest possible stiffening and prevents thermal expansion of the perforated sheet 26.

[0040] However, it is also possible that, for example, corner areas of the perforated sheet 26 do not have an embossing 40.

[0041] The embossing 40 is formed in particular between the peripheral edge 30 and the base surface 34, so that depending on the embodiment, the embossed area can have holes 36 or alternatively, like the peripheral edge 30, has no holes 36.

[0042] The surface 42 surrounded by the embossing 40 is parallel to the base surface 34 of the perforated sheet 26. In particular, the surface 42 surrounded by the embossing 40 corresponds to the base surface 34.

[0043] As particularly in Fig. As can be seen in Figure 4, the embossing 40 shown is V-shaped. Of course, instead of a V-shaped embossing 40, which is also referred to as a triangular bead, a semicircular bead, a box bead, or a trapezoidal bead can also be used.

[0044] In Fig. Figure 5 shows the temperature distribution in the cooking chamber 14 and in the inner pane 22. It can be seen that a temperature hotspot 44 occurs in the inner pane 22 due to the embossing 40 in the perforated sheet 26. This is because the perforated sheet 26 reflects the microwaves in a concentrated manner due to the embossing 40, so that the microwaves impinge on the inner pane 22 along a bending line 46, where the temperature hotspot 44 occurs.

[0045] Based on the shape and / or location of the embossing 40, the temperature hotspot 44 can be shifted on the inner pane 22 so that the resulting temperature hotspots 44 can be directed to comparatively less risky areas.

[0046] Additionally, other components in the area of ​​the cooking chamber door 18 that are sensitive to temperature can also be protected. These include, for example, a cooking chamber seal and lighting, which are not shown in the figures for clarity. By specifically directing the temperature hotspots 44, the temperature of individual components can be reduced so that they can be touched by a user.

[0047] The glass panes used in the cooking chamber door 18 are typically tempered soda-lime glass. However, the tempering in soda-lime glass is reduced at a glass temperature of approximately 280°C, making the glass pane more prone to cracking. Therefore, it is important to avoid unwanted temperature hotspots 44 to prevent damage to the pane, especially upon contact with cold liquids.

[0048] This is ensured by the embossing 40, as the temperature hotspots 44 are directed to areas where (cold) liquids typically do not come into contact with the pane. Therefore, there is no risk of the glass pane shattering.

[0049] Another embodiment of a cooking chamber door 18 is shown in Fig.6, in which, in addition to the expansion space 38, at least one spacer 48 is provided, which is arranged between the inner pane 22 and the perforated plate 26, in particular contacts both the inner pane 22 and the perforated plate 26.

[0050] As an alternative to the embodiment shown, the expansion space 38 can be provided between the outer pane 24 and the perforated plate 26, so that the at least one spacer 48 is then arranged between the outer pane 24 and the perforated plate 26, in particular contacts the outer pane 24 and the perforated plate 26.

[0051] It is also possible that two expansion spaces are provided, namely between the inner pane 22 and the perforated plate 26 and between the outer pane 24 and the perforated plate 26. At least one spacer 48 can then be provided in each of the two expansion spaces.

[0052] Preferably, a plurality of spacers 48 are provided, which are evenly distributed over the surface 42, for example four spacers 48 or six spacers 48.

[0053] The spacers 48 are preferably made of Teflon so that they can withstand high temperatures, i.e., temperatures above 300°C, and do not leave marks on the inner pane 22 or the outer pane 24. The spacers 48 allow the perforated plate 26 to be positioned centrally and to maintain this position even during operation of the cooking appliance 10.

Claims

[1] Cooking chamber door (18) for a cooking appliance (10) with a microwave unit (16), comprising at least one inner pane (22), one outer pane (24) and a perforated plate (26), wherein the perforated plate (26) is arranged between the inner pane (22) and the outer pane (24), wherein the perforated plate (26) has a distance from the inner pane (22) and / or outer pane (24), so that an expansion space (38) is provided for the perforated plate (26), and wherein the perforated plate (26) has an embossing (40), characterized by that the embossing (40) on the inner pane (22) results in at least one temperature hotspot (44). [2] Cooking chamber door (18) according to claim 1, characterized by that the embossing (40) is provided on the side of the perforated plate (26) which faces the inner pane (22). [3] Cooking chamber door (18) according to one of claims 1 and 2, characterized bythat the embossing (40) is arranged to reflect the microwaves reflected from the perforated plate (26) in a bundled manner along a bending line (46) onto the inner pane (22). [4] Cooking chamber door (18) according to one of the preceding claims, characterized by that the embossing (40) is formed circumferentially on the perforated plate (26). [5] Cooking chamber door (18) according to claim 4, characterized by that the embossing (40) is designed such that the perforated plate (26) has a flat surface (42) within the circumferential embossing (40) which is parallel to a base surface (34) of the perforated plate (26). [6] Cooking chamber door (18) according to one of the preceding claims, characterized by that the embossing (40) of the perforated plate (26) is U- or V-shaped. [7] Cooking chamber door (18) according to one of the preceding claims, characterized bythat the perforated plate (26) has a peripheral edge (30) and a flat base surface (34) in which holes (36) are provided, wherein the embossing (40) is formed between the peripheral edge (30) and the base surface (34). [8] Cooking appliance (10) for cooking food, comprising a cooking chamber (14), a microwave unit (16) and a cooking chamber door (18) comprising at least one inner pane (22), an outer pane (24) and a perforated plate (26), wherein the perforated plate (26) is arranged between the inner pane (22) and the outer pane (24), wherein the perforated plate (26) has a distance to the inner pane (22) and / or a distance to the outer pane (24), so that an expansion space (38) for the perforated plate (26) is provided between the inner pane (22) and the perforated plate (26) and / or an expansion space (38) for the perforated plate (26) is provided between the outer pane (24) and the perforated plate (26), wherein at least one spacer (48) is arranged at least between the inner pane (22) and the perforated plate (26), and / or wherein between the outer pane (24) and the At least one spacer (48) is arranged in the perforated plate (26). [9] Cooking appliance (10) according to claim 8, characterized bythat at least two spacers (48) are provided, in particular more than two spacers (48), which are evenly distributed over the surface (42) of the perforated plate (26).

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