CN118044335A - Cooking chamber door for microwave cooking appliance and microwave cooking appliance - Google Patents
Cooking chamber door for microwave cooking appliance and microwave cooking appliance Download PDFInfo
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- CN118044335A CN118044335A CN202280064457.1A CN202280064457A CN118044335A CN 118044335 A CN118044335 A CN 118044335A CN 202280064457 A CN202280064457 A CN 202280064457A CN 118044335 A CN118044335 A CN 118044335A
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- 238000010411 cooking Methods 0.000 title claims abstract description 91
- 230000004888 barrier function Effects 0.000 claims abstract description 7
- 238000005192 partition Methods 0.000 claims description 44
- 238000005452 bending Methods 0.000 claims description 34
- 125000006850 spacer group Chemical group 0.000 claims description 17
- 230000005855 radiation Effects 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- 230000006872 improvement Effects 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000003466 welding Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 101100204059 Caenorhabditis elegans trap-2 gene Proteins 0.000 description 2
- 238000013016 damping Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000003698 laser cutting Methods 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B6/00—Heating by electric, magnetic or electromagnetic fields
- H05B6/64—Heating using microwaves
- H05B6/76—Prevention of microwave leakage, e.g. door sealings
- H05B6/763—Microwave radiation seals for doors
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- Electric Ovens (AREA)
Abstract
A cooking chamber door (T) for a microwave cooking appliance (G) having at least one lambda-trap (2) with a plurality of barrier teeth (4) arranged adjacently in rows, the bases of the barrier teeth lying in the same plane (3), wherein at least two of the barrier teeth (4) have different heights (h). A microwave cooking appliance (G) having a cooking chamber with a charging opening surrounded by a muffle flange (7); and having a cooking chamber door (T) according to any one of the preceding claims. The invention can be used particularly advantageously in microwave cooking appliances having an uneven, in particular convex, muffle flange.
Description
Technical Field
The invention relates to a cooking chamber door for a microwave cooking appliance, comprising at least one lambda-trap having a plurality of partition teeth arranged adjacently in rows, the bases of the partition teeth lying in the same plane. The invention also relates to a microwave cooking appliance having a cooking chamber, the charging opening of which is surrounded by a muffle flange; and has such a cooking chamber door. The invention is particularly advantageously applicable to microwave cooking appliances having uneven, in particular convex, muffle flanges.
Background
A household microwave cooking appliance requires shielding means to prevent microwaves from passing between its closed door and a muffle flange (Muffelflansch) opposite the door when the microwaves are running. As shielding means, microwave traps in the form of so-called Lambda/4 or Lambda quarter traps (Lambda-Viertel-Falle) are well known. The lambda quarter trap may be a trap immersed in the cooking chamber, as described in DE 3328748 A1, and/or may be arranged on the door, for example behind an inner glass plate of the door, as described in EP 1 426 692 A1 or DE 28 536 16 A1. Also known are microwave traps consisting of two or more lambda quarter traps cascaded one behind the other, as disclosed in EP 2 271 177 A1.
Particularly common is a lambda quarter trap on the outer edge of the door, which is covered by a microwave-transparent (mikrowellentransparenten) material in order to prevent damage and soiling, as disclosed in US 20110290230 A1 and EP 3 225 079 A1. A particularity of EP 3 225,079 A1 is that the lambda trap is also suitable for a muffle flange, which is not geometrically in one plane, but is spherically shaped (so-called "bulge (Bombierung)"). The formation of such a sphere provides thermal and deformation properties, in particular of the flange under the influence of heat. The disadvantage in this case is, of course, an increased complexity in the overall construction of the door. In order to achieve adequate tightness, the current state of the art requires a complex deep-drawn door which perfectly follows the spherical profile of the flange, and a partition which must be fastened by welding to the bottom of the door, as described in EP 3 225 079 A1. Since bending along the curved edges is not possible, it has not been possible to produce doors in the form of deep-drawn and folded components in a way that is simple to design and inexpensive.
Disclosure of Invention
The object of the present invention is to at least partially overcome the disadvantages of the prior art and in particular to provide a cooking chamber door for a microwave cooking appliance that can be produced simply and cost-effectively and that, in the closed state, enables a high attenuation of microwaves even if the muffle flange is uneven.
This object is achieved according to the features of the independent claims. Preferred embodiments are found in particular in the dependent claims.
The object is achieved by a cooking chamber door for a microwave cooking appliance, comprising at least one microwave trap structure according to the lambda-trap principle, which has a plurality of partition teeth arranged adjacent (nebeneinander) in rowsThe bases of the diaphragm teeth lie in the same plane, wherein at least two of the diaphragm teeth have different heights.
Since the bases of the diaphragm teeth lie in the same plane, they can be produced simply and inexpensively by means of a bending process along a rectilinear edge ("main bending line"). By means of their different heights, the advantage is achieved that their distance from the muffle flange of the charging opening to be closed by the cooking chamber door, in particular also from uneven, for example convex, muffle flanges, can be adjusted. This in turn enables a high attenuation to be maintained.
The muffle flange is understood to mean, in particular, a flange surrounding the filling opening of the cooking chamber (also referred to as muffle) or a band-shaped curved edge of the muffle. The muffle flange may be an integral partition of the muffle or may be separately manufactured and then fastened to the muffle, such as welded thereto.
The spacer teeth are understood to be, in particular, strips bent up from a strip-shaped edge ("spacer") such as, for example, from a sheet metal along a main bending line, in particular at 90 °. The attachment of the strip to the main bend line may also be referred to as its base. Starting from its base, the diaphragm tooth is bent again or in most cases twice more, in particular in each case again by 90 ° in the same direction, so that the diaphragm tooth forms an "L" shape in the case of a single bending and an angular "U" shape in the case of a double bending. The L-shaped baffle teeth can be produced in particular at low cost, while the U-shaped baffle teeth enable particularly effective microwave attenuation. Only microwave traps having "U" -shaped baffle teeth are further described below without limiting versatility.
Adjacently disposed bulkhead teeth may be understood in particular as bulkhead teeth which are arranged in succession along a common main bending line.
The height of the spacer teeth corresponds in particular with a 90 ° bend angle to the length of the section between the main bending line and the subsequent first bending line ("first tooth section"). This is similar to the distance between two bending lines following the main bending line and the section between the planes defined by the webs ("second tooth section") at a 90 ° bend angle. The fact that at least two of the separator teeth have different heights may also mean that the length of the first tooth section for at least two of the separator teeth is different.
However, the basic shape of the diaphragm teeth can in principle also be designed otherwise. In this way, the individual tooth sections can be configured straight or at least one of the tooth sections can be configured curved. Tooth sections meeting at a bending line or bending lines may also have a bending angle therein of more or less than 90 °.
One improvement is that all of the spacer teeth have the same width and/or basic shape (e.g., the same bend angle). One improvement is that the second tooth sections of all the diaphragm teeth have the same length.
One improvement is that the lambda trap has a row of circumferential spacer teeth. In this case, in particular, four diaphragm sections or edge sections are formed, each having a plurality of diaphragm teeth arranged next to one another, wherein the diaphragm teeth of a common edge section have the same main bending line. The edge sections may in particular comprise an upper edge section which runs horizontally when the door is set up, a lower edge section which runs parallel to the upper edge section and at a distance from it, a left edge section which runs vertically when the door is set up, and a right edge section which runs parallel to the left edge section and at a distance from it. The edge sections can be directly connected to one another or can have a transition section with a separator tooth between two respective edge sections, which has a main bending line that is inclined to the edge sections.
One design is that the height of the partition teeth arranged on the common edge section of the cooking chamber door increases from the center of the edge section to the ends of the edge section. It is particularly advantageous if the cooking chamber door is arranged to cover, for example, a spherical or ellipsoidal convex muffle flange.
One design is that at least two separator teeth arranged next to each other on a common edge section have the same height. This simplifies the manufacture of the diaphragm teeth. Another advantage is that if the section of the muffle flange opposite the baffle teeth is not flat, a slightly different distance from the muffle flange by the baffle teeth gives rise to a widening of the effective frequency of the trap under superposition.
One design is that the spacer tooth with a greater height has a tooth section between the edge of the end side and the closest bend line thereof ("third") that has a length that is smaller than the length of the third tooth section of the spacer tooth with a relatively smaller height. This achieves the advantage that the effective frequency shift of the diaphragm tooth can be corrected to the desired effective frequency, in particular can be completely compensated, by changing the length of its third tooth section.
One improvement is that the length of the diaphragm tooth (that is to say its length in the unbent state) and the length of the second tooth section are identical for at least two diaphragm teeth having different heights. This means that the first tooth segment length plus the third tooth segment length, which corresponds to the height of the separator tooth, is the same for the separator tooth. Thus, if one separator tooth has a greater height than the other separator tooth, its third tooth segment is shorter to the same extent. Alternatively, however, the length of the spacer teeth may be different for at least two spacer teeth having different heights.
In one embodiment, the cooking chamber door has an overlap surface protruding on the appliance side in the region enclosed by the partition teeth and thus also by the partition, which overlap surface is configured to follow the shape of the muffle flange. In this way, a door gap with a uniform gap width can advantageously be set between the overlapping surface and the muffle flange when the door is closed.
One design is that the diaphragm teeth are machined from a diaphragm that represents the door bottom edge area integral with the door bottom of the cooking chamber door. In other words, the partition with the partition teeth represents an integral partition of the bottom of the integrated door. Since the spacer teeth can have different heights, the bending lines of the spacer teeth can run straight even if the overlapping surfaces are uneven. In this way, it is advantageously possible to dispense with the separate production of the partition provided with the partition teeth and subsequent fastening to the door bottom by welding. By eliminating the welding process, the door bottom can be manufactured more cost-effectively, more consistently and more accurately, for example, by reducing the small effects caused by thermal welding distortion and part alignment accuracy variations. This allows the door bottom to be manufactured more accurately in large batches and reproducibly with small deviations.
The object is also achieved by a microwave cooking appliance having a cooking chamber, the charging opening of which is surrounded by a muffle flange; and has a cooking chamber door as described above. The microwave cooking appliance may be constructed similarly to a cooking chamber door and vice versa, with the same advantages.
An improvement is that the microwave cooking appliance is a household microwave cooking appliance. The microwave cooking appliance may be a stand-alone appliance or may be a combination appliance. The combination may be, for example, an oven/microwave combination, a microwave/steam cooking combination, or a combination having all three functions.
One design is that the muffle flange is an uneven muffle flange. This may be advantageous for improving the thermal and deformation properties of the muffle flange under the influence of heat. An uneven muffle flange is understood to mean, in particular, a muffle flange whose surface on the door side does not lie in a plane. In particular the door side surface of such a muffle flange may have a height variation in the circumferential direction.
One design is that the muffle flange is a muffle flange that is convex at least in sections in the circumferential direction, either geodesic or ellipsoidal. This can be produced particularly simply. Such a muffle flange is to be understood as meaning, in particular, a muffle flange whose door-side surface has the shape of a sphere or ellipsoid protruding toward the door along at least one of its (upper, lower, left and/or right) edge sections. In one refinement only the upper and lower edge sections are convex, in another refinement only the left and right edge sections are convex, and in yet another refinement all edge sections are convex. In principle, however, the surface shape of the muffle flange is not limited and may, for example, be wavy or free-shaped in the circumferential direction.
One design is that the muffle flange is an uneven muffle flange and that the distance ("tooth pitch") d of the baffle teeth from the muffle flange is at least approximately equal when the cooking chamber door is closed. In this way, a particularly high maximum attenuation can advantageously be achieved even only in a relatively narrow microwave frequency range.
The tooth pitch d of the bulkhead teeth is to be understood as the shortest distance to the muffle flange, in particular, when the door is closed. The tooth pitch may correspond to the distance of the front edge of the first tooth section from the muffle flange in the case of a baffle tooth bent vertically from the baffle plane. In the case of a 90 ° bend relative to the first tooth section, this also corresponds to the distance of the second tooth section from the muffle flange. The tooth pitch d can be set by selecting the height h of the diaphragm tooth, for example, according to d=c-h, where c is the distance ("gate pitch") of the base of the diaphragm tooth or the diaphragm plane from the muffle flange.
One design is that the tooth distance d of the partition tooth and the muffle flange is within a predetermined bandwidth b when the cooking chamber door is closed, wherein b >0. Thus, for example, the spacer teeth having the same gate spacing c can have different heights of a maximum of b, or the spacer teeth having different gate spacing of a maximum of b can have the same height. A more effective damping effect of the microwave trap, whether a flat or uneven muffle flange, can thereby be achieved over a wider microwave frequency range.
It has proved to be particularly advantageous if the bandwidth b is at least approximately 0.5mm, since this gives a particularly advantageous widening of the effective frequency of the microwave trap and at the same time a particularly effective attenuation.
One of the designs is that of a design,
The muffle flange is an uneven muffle flange,
Conceptually, the base of the partition teeth, in particular of the common edge section, and the gate distance c of the opposing muffle flange can be subdivided, starting from a minimum distance c 0, into a plurality of successive steps ("distance steps") and
The door has the same height from the bulkhead teeth belonging to a determined distance class.
This design advantageously makes it possible to achieve a widening of the effective frequency of the microwave trap particularly simply in terms of design. The door distance c, which also corresponds to the local distance of the bulkhead from the muffle flange, is also imaginarily subdivided into classes [ c 0;c0+s1[,[c0+s1;c0+s2 [, where s 1、s2 is the class height of the first, second height classes. All of the spacer teeth in which the gate distance c falls into one of the height levels have the same height. The smallest distance c 0 occurs in the region of the muffle flange that projects furthest toward the door or the partition, for example, in the case of a spherically convex edge section, typically the center thereof.
One improvement is that the grade heights are the same, i.e. s 1＝s2 =.
One design is that the class height s corresponds to a preset bandwidth b, i.e. s=b. Which may advantageously be about 0.5mm.
One design is that the height of the spacer teeth of a determined distance class corresponds to the average distance of the distance class minus a preset bandwidth. The height h 1 associated with the first distance class [ c 0;c0 +b ] is therefore h 1＝(c0+c0+b)/2-b＝c0+b/2-b＝c0 -b/2. The height h 2 of the separator teeth associated with the second distance class [ c 0+b;c0 +2.b [ which links the first distance class ] is h 2＝(c0+c0+3·b)/2-b＝c0 +b/2, etc. In particular, the height of the diaphragm teeth increases with the bandwidth b with successive distance steps. The tooth pitch d can in particular remain in the same value range for different distance classes.
In one example, assume c 0 = 5mm and b = 0.5mm. Thus, the door distance c= [5; all the baffle teeth of 5.5[ mm opposite to a section of the muffle flange can for example have the same height h 1 =4.75 mm and thus have a height in the range [0.25; tooth pitch d in 0.75 mm. With a gate distance c= [5.5; all the baffle teeth of 6[ mm opposite a section of the muffle flange can for example have the same height h 2＝h1 +b=5.25 mm and thus likewise have a height in the range [0.25;0.75 mm, etc.
Drawings
The above features, features and advantages of the present invention, and the manner of attaining them and the method of attaining them, will become more apparent and be better understood by reference to the following description of exemplary embodiments of the invention taken in conjunction with the accompanying drawings.
Fig. 1 shows a door bottom of a cooking chamber door for a microwave cooking appliance in a view from obliquely above, with a partition having a plurality of partition teeth;
fig. 2 shows a schematic view of a partition tooth in a side view as a sectional view, which is opposite a muffle flange of a microwave cooking appliance with a cooking chamber door closed;
fig. 3 shows in a side view, as a sectional view, a bulkhead tooth mounted into the cooking chamber door, which is opposite a muffle flange of the microwave cooking appliance with the cooking chamber door closed;
fig. 4 shows a schematic representation of the edge section of the muffle flange, with opposite baffle sections, in plan view;
Fig. 5 shows a schematic view, not to scale, of the edge section of the muffle flange in a plan view similar to fig. 4, with opposed bulkhead sections, without bulkhead teeth;
FIG. 6 illustrates the attenuation effect of a microwave trap having identical baffle teeth, not according to the present invention, as a plot of microwave radiation transmission versus microwave frequency; and
Fig. 7 shows the attenuation effect of a microwave trap according to the invention with different barrier teeth as a graph of the transmission of microwave radiation versus the microwave frequency.
Detailed Description
Fig. 1 shows a door bottom 1 of a cooking chamber door T for a microwave cooking appliance G in a view from obliquely above, with a partition 3 having a plurality of teeth machined from it ("partition teeth" 4) as a microwave trap 2 in the form of a lambda-quarter trap. The cooking chamber door T can in particular be manufactured from a single sheet metal part, for example by means of known material processing methods such as cutting (for example laser cutting), bending, deep drawing, etc.
The door bottom 1 now has an overlap surface, in particular surrounding the projectionA landing surface) 5, which encloses a through-opening for a microwave sealing window 6, shown here inserted, and which, after installation into a microwave cooking appliance G, is located opposite a muffle flange 7 (see for example fig. 2 and 3). The overlapping surface 5 follows the shape of the muffle flange 7 so that a gap with an at least approximately uniform gap width is obtained between them in the case of a closed cooking chamber door T. If the surface of the muffle flange 7 opposite the cooking chamber door T is not flat, the overlapping surface 5 is also not flat. The partition 3 surrounding the overlapping surface 5 from the outside circumferentially represents the edge region of the door bottom 1.
As also shown in fig. 2, adjacently disposed separator teeth 4 of respective sections of separator 3 are bent at about 90 ° relative to the plane of the remaining separator 3 by following a common straight main bend line 8. The position of the main bending line 8 thus also corresponds to the position of the base or foot of the separator tooth 4.
Each of the separator teeth 4 is also bent in the same direction by about 90 ° on one other bending line 9 and then bent in the same direction by about 90 ° on yet another bending line 10. Each separator tooth 4 thus has a "U" shape with a first, in particular straight, tooth section 11 extending between the main bending line 8 and the bending line 9, a second, in particular straight, tooth section 12 extending between the bending line 9 and the bending line 10, and a third, in particular straight, tooth section 13 extending between the bending line 10 and the end side edges of the separator tooth 4.
The maximum height perpendicular to the plane of the diaphragm 3 corresponds to the height h of the diaphragm teeth 4. If the tooth sections 11, 12 and 13 are bent straight and at an angle of 90 ° to one another, the height h of the spacer tooth 4 corresponds to the length of the first tooth section 11.
With the cooking chamber door T closed, the partition 3 has a defined distance ("gate distance") c from the muffle flange in some areas, and the partition teeth 4 bent from the partition 3 have a distance ("tooth distance") d from the muffle flange 7. In particular, d=c-h may be at least approximately.
As shown in fig. 1, the partition plate 3 has four sections in its circumferential direction, namely an upper section 3a, a lower section 3b, a left section 3c, and a right section 3d in the state where the cooking chamber door T is built up. Each of the sections 3a to 3d has a plurality of separator teeth 4 arranged adjacently in rows. The separator teeth 4 of each of the segments 3 a-3 d have the same main bend line 8, respectively, but need not have the same bend lines 9 and 10. The main bending lines 8 of the upper and lower sections 3a, 3b are parallel to each other and perpendicular to the main bending lines 8 of the left and right sections 3c, 3d. In addition, a comparatively short transition section 3e is provided here, for example, between the sections 3a to 3d, which each has a single diaphragm tooth 4 whose main bending line is angularly offset by 45 ° from the main bending line 8 of the adjoining sections 3a to 3d. With this well geometry, complete shielding is achieved even in the corners.
Fig. 3 shows, as a sectional view, a partition tooth 4 which is installed into the cooking chamber door T in a side view, opposite the muffle flange 7 of the microwave cooking appliance G with the cooking chamber door T closed and thus the front covered cooking chamber 16. In addition to fig. 1 and 2, a cover 14 is now also shown which is fitted over the diaphragm tooth 4, for example for protecting the diaphragm tooth 4. A sealing element 15 is arranged on the cover element 14, which seals the gap between the overlapping surface 5 and the cover element 14. The cover 14 and/or the seal 15 may be made of a microwave transparent material, such as a silicon material.
Fig. 4 shows a schematic view of one edge section of the muffle flange 7 in a top view, with the opposite edge section or partition section 3a, 3b, 3c or 3d of the cooking chamber door T. The surface of the muffle flange 7 facing the cooking chamber door T is uneven, i.e. symmetrical in the direction of extension, with an earth or ellipsoidal convex. In particular the muffle flange may have a surface resembling the shape of a rotational ellipsoid.
Fig. 5 shows a schematic representation of an edge section of the muffle flange 7 in a plan view similar to fig. 4, with opposite edge sections of the partition 3 or partition sections 3a, 3b, 3c or 3d, without partition teeth having different section ranges a 1、A2 and a 3 and distances c 0 to c 3 and b.
Referring to fig. 5, the gate distance c between the baffle 3 (and thus the base of the baffle teeth) and the muffle flange 7 increases from the shortest gate distance c 0 in the center of the section towards the edge, depending on the shape of the muffle flange 7. The value range of the gate distance c obtained here can be subdivided, conceptually, starting from the shortest gate distance c 0, into a plurality of (here: three) partitions or distance classes, here, for example, three distance classes [ c 0;c0+b[,[c0+b;c0 +2·b [ and [ c 0+2·b;c0 +3·b [, wherein the class heights of all distance classes correspond to the bandwidth b, respectively. Associated with these three distance classes is the corresponding section range a 1、A2 or a 3.
Referring now additionally to fig. 4, the door distance c belongs to the first (minimum) distance class and therefore all of the bulkhead teeth 4-1 falling into the zone range a 1 have the same height h 1. The height h 1 may be, for example, h 1＝c0 -b/2. The door distance c belongs to the second distance class and therefore all diaphragm teeth 4-2 falling into the section range a 2 have the same height h 2. The height h 2 may be, for example, h 2＝c0 +b/2. The door distance c belongs to the third distance class and therefore all diaphragm teeth 4-3 falling into the section range a 3 have the same height h 3. The height h 3 may be, for example, h 3＝c0 +3/2·b. This principle can be generalized to less or more than three distance levels and/or other shapes of the muffle flange 7, if desired.
One possibility is to correct for an undesired shift of the maximum effective frequency of the individual diaphragm teeth 4-1, 4-2, 4-3 due to the different heights h 1、h2、h3 of the diaphragm teeth 4-1, 4-2 or 4-3 in such a way that the third tooth section 13 thereof is changed, in particular in such a way that the total tooth length resulting from the addition of the lengths of the individual tooth sections 11, 12 and 13 and the length of the second tooth section 12 remain constant.
Fig. 6 shows the transmission of microwave radiation (in dB) through a microwave trap not according to the invention in the mode |s 21 | versus the microwave frequency f (in MHz). The diagram is established by simulating a household appliance G having a flat muffle flange and a cooking chamber door similar to the cooking chamber door T of fig. 1, but having partition teeth of the same and in particular of the same height. If, as is usual so far, the geometry of the baffle teeth surrounding the cooking chamber door is exactly the same, then the ideal effective frequency of the microwave trap (at which the attenuation is greatest) is also exactly the same.
The ideal effective frequency is approximately centered in the ISM band considered herein, ranging between 2400MHz and 2500 MHz. The main effective frequency of the microwave source, in this case 2446MHz under the magnetron, is ideally chosen. Transmission at the ideal effective frequency achieves-80 dB attenuation. In order to achieve a perfect attenuation effect, at least-60 dB attenuation should be achieved in the frequency range of the effective frequency between 2435MHz and 2457MHz plotted and thus a frequency width of about 22MHz, as indicated by the double arrow shown by the dashed line. Outside this frequency range, increased leakage radiation may occur in some cases, which should be avoided for reasons of standardization if necessary for the safety of the user.
Depending on tolerances occurring during the manufacture of the microwave cooking appliance, the frequency range of the effective frequency with an attenuation of at least-60 dB may deviate. Furthermore, microwave sources are not generally frequency stable: the magnetron having an operating frequency of any value within 2420MHz to 2480MHz is operated within its specification range. It is therefore advantageous to use a microwave trap whose frequency range of the effective frequency with an attenuation of at least-60 dB is as wide as possible. The absolute "attenuation depth" is minor: if the leakage radiation of 0.5mW/cm 2 is emitted at an attenuation of-60 dB, the leakage radiation of 0.05mW/cm 2 is emitted at an attenuation of-70 dB, and the leakage radiation of 0.005mW/cm 2 is emitted at an attenuation of-80 dB. This is well below the usual limit of 1.0mW/cm 2 to 10mW/cm 2. However, as indicated above, a value of 0.05mW/cm 2 can only be achieved within a narrower frequency band. Outside this frequency band, the value increases rapidly, reaching inadmissibly high values even if the geometrical deviations or frequency variations of the magnetron are small. This increases the pressure to maintain tight manufacturing tolerances and/or to use magnetrons with narrow operating bands. Both of which greatly increase the cost of the microwave cooking appliance.
Fig. 7 shows a graph of the attenuation of the transmission of microwave radiation in the mode |s 21 | versus the microwave frequency f (in MHz) for a microwave trap 2 with partition teeth 4-1, 4-2, 4-3 of different heights, as is in principle the case with reference to partition teeth 4-1, 4-2, 4-3 shown in fig. 4. The hierarchical division of the height of the diaphragm teeth 4-1, 4-2, 4-3 brings about a surprising advantage.
This is due to the slight shift in the effective frequency of each baffle tooth caused by the change in geometry of the muffle flange locally in the opposed baffle teeth. As can be seen from fig. 4, the tooth spacing d between the diaphragm teeth 4-1, 4-2, 4-3 and the muffle flange 7 is different in most, in particular in all diaphragm teeth 4-1, 4-2, 4-3. The pitch d influences the damping effect of the respective diaphragm tooth 4-1, 4-2, 4-3, which results in a deviation of the position of the respective ideal effective frequency. In this case, in particular, there is no longer only one microwave trap acting in a unified manner, but rather a superposition of a plurality of traps, which correspond to the individual partitions 4-1, 4-2, 4-3.
The total effect of the shown superposition reduces the maximum attenuation value, but as mentioned above, this is not decisive. The bandwidth of the effective frequency (with an attenuation of at least-60 dB) is in turn advantageously increased from about 22MHz to about 28MHz. Improved stability with respect to manufacturing tolerances and/or the use of microwave sources with larger frequency variations is thereby obtained.
Of course, the invention is not limited to the embodiments shown.
The invention can thus also be applied to flat muffle flanges in general. Deviations or variations in the geometry of the diaphragm teeth can be introduced in a targeted manner, resulting in a shift in the effective frequency thereof. These deviations may for example relate to the length of the first tooth section and thus the height of the separator tooth and/or the length of the third tooth section. The length of the second tooth section may also be varied in some cases.
In general, "a (an)", "an (eine)" and the like are to be understood as singular or plural, particularly "at least one" or "one or more" and the like, unless explicitly excluded from this, such as "exactly one" and the like.
Numerical descriptions may also include the numbers given as well as the usual ranges of tolerances, provided that they are not explicitly excluded.
List of reference numerals
1 Door bottom
2 Microwave trap
3 Partition board
3A-3e separator sections
4 Baffle teeth
5 Overlapping surfaces
6 Window
7 Muffle flange
8 Main bending line
9 Bending line
10 Bending line
11 First tooth segment
12 Second tooth segment
13 Third tooth segment
14 Cover piece
15 Seal
16 Cooking chamber
C door distance
D pitch
G microwave cooking utensil
H height of partition teeth
T-shaped cooking chamber door
Claims (14)
1. A cooking chamber door (T) for a microwave cooking appliance (G) having at least one lambda-trap (2) with a plurality of barrier teeth (4) arranged adjacently in rows, the bases of the barrier teeth lying in the same plane (3), wherein at least two of the barrier teeth (4) have different heights (h).
2. Cooking chamber door (T) according to claim 1, wherein the height (h) of the partition teeth (4) arranged on the common edge section (3 a-3 d) of the cooking chamber door (T) increases from the centre of the edge section (3 a-3 d) towards the end of the edge section (3 a-3 d).
3. Cooking chamber door (T) according to claim 2, wherein at least two partition teeth (4) arranged adjacently on a common edge section (3 a-3 d) have the same height.
4. Cooking chamber door (T) according to any one of the preceding claims, wherein the partition tooth (4) with a greater height (h) has a third tooth section (13) between the edge of the end side and the bending line (10) closest thereto, the length of which is smaller than the length of the third tooth section (13) of the partition tooth (4) with a relatively smaller height (h).
5. Cooking chamber door (T) according to any one of the preceding claims, wherein the cooking chamber door (T) has an overlapping surface (5) protruding on the appliance side within the area enclosed by the partition tooth (4), said overlapping surface being configured following the shape of a muffle flange (7).
6. Cooking chamber door (T) according to any of the preceding claims, wherein the bulkhead teeth (4) are machined from a bulkhead (3) representing an integral edge area of the door bottom (1) of the cooking chamber door (T).
7. A microwave cooking appliance (G) having a cooking chamber with a charging opening surrounded by a muffle flange (7); and having a cooking chamber door (T) according to any one of the preceding claims.
8. Microwave cooking appliance (G) according to claim 7, wherein the muffle flange (7) is an uneven muffle flange (7) and the tooth pitch (d) of the baffle teeth (4) and the muffle flange (7) is at least approximately equal with the cooking chamber door (T) closed.
9. Microwave cooking appliance (G) according to claim 7, wherein the pitch (d) of the baffle teeth (4) and the muffle flange (7) is within a preset bandwidth (b).
10. The microwave cooking appliance (G) according to claim 9, wherein the bandwidth (b) is at least about 0.5mm.
11. The microwave cooking appliance (G) according to any one of claims 9 to 10, wherein,
-The muffle flange (7) is an uneven muffle flange (7),
-The base of the partition teeth (4) of the common edge section (3 a-3 d) and the gate distance (c) of the muffle flange (7) can be subdivided, starting from a minimum gate distance (c 0), into a plurality of successive distance classes, in particular of the same class height, and
-All the bulkhead teeth (4) of which the door distance (c) belongs to a determined distance class have the same height (h).
12. The microwave cooking appliance (G) according to claim 11, wherein the distance levels have the same level height and the level height corresponds to a preset bandwidth (b).
13. Microwave cooking appliance (G) according to claim 12, wherein the height (h) of the spacer teeth (4) of a determined distance level corresponds to the average door distance (c) of the distance level minus the bandwidth (b).
14. Microwave cooking appliance (G) according to any one of claims 7 to 13, wherein the muffle flange (7) is at least sectionally an outwardly convex muffle flange (7).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102021210592.0 | 2021-09-23 | ||
| DE102021210592.0A DE102021210592A1 (en) | 2021-09-23 | 2021-09-23 | Cooking chamber door for a microwave oven and microwave oven |
| PCT/EP2022/074569 WO2023046447A1 (en) | 2021-09-23 | 2022-09-05 | Cooking chamber door for a microwave oven and microwave oven |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118044335A true CN118044335A (en) | 2024-05-14 |
Family
ID=83398256
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202280064457.1A Pending CN118044335A (en) | 2021-09-23 | 2022-09-05 | Cooking chamber door for microwave cooking appliance and microwave cooking appliance |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN118044335A (en) |
| DE (1) | DE102021210592A1 (en) |
| WO (1) | WO2023046447A1 (en) |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA742105B (en) * | 1973-05-02 | 1975-03-26 | Amana Refrigeration Inc | Multilength microwave oven choketype energy seal |
| CA1120551A (en) | 1977-12-13 | 1982-03-23 | Shuji Ohkawa | Door seal arrangement for high-frequency heating apparatus |
| JPS5933793A (en) | 1982-08-18 | 1984-02-23 | 松下電器産業株式会社 | High frequency heater |
| KR0176801B1 (en) * | 1995-12-29 | 1999-05-15 | 구자홍 | Microwave leakage shielding apparatus for microwave oven |
| DE10256624B4 (en) | 2002-12-03 | 2005-12-08 | Miele & Cie. Kg | microwave oven |
| EP2271177B1 (en) | 2009-07-02 | 2013-02-27 | Electrolux Home Products Corporation N.V. | A wave choke system for an oven door of a microwave oven |
| US9179506B2 (en) | 2010-05-26 | 2015-11-03 | Lg Electronics Inc. | Door choke and cooking apparatus including the same |
| DE102014224053A1 (en) * | 2014-11-25 | 2016-05-25 | BSH Hausgeräte GmbH | Haushaltsgargerät |
| EP3057381B1 (en) * | 2015-02-11 | 2017-08-23 | Electrolux Appliances Aktiebolag | An oven door for a microwave oven |
-
2021
- 2021-09-23 DE DE102021210592.0A patent/DE102021210592A1/en active Pending
-
2022
- 2022-09-05 WO PCT/EP2022/074569 patent/WO2023046447A1/en active Application Filing
- 2022-09-05 CN CN202280064457.1A patent/CN118044335A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE102021210592A1 (en) | 2023-03-23 |
| WO2023046447A1 (en) | 2023-03-30 |
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