EP1853094A1 - Microwave antennas configuration, accessory with such a microwave antennas configuration and equipment with at least such an accessory - Google Patents

Abstract

The configuration has a cooking chamber, in which an accessory (1) is arranged for positioning by two cooking product container in the cooking chamber in order to treat cooking items on the cooking product container in two certain handling level at times. The antennas (4,4a-4f,4'a-4'f) are formed as fourth part of detuned wavelength bars in order to load cooking items in handling level with equal microwave energy. Independent claims are also included for the following: (1) an accessory for cooking appliance (2) a cooking appliance has cooking chamber.

Description

The invention relates to an antenna configuration for a cooking appliance with a cooking chamber, in which at least one accessory for introducing at least two food supports in the cooking chamber for the treatment of food on the Gargutträgern in at least two each determined by a food support treatment levels at least temporarily, which is a variety of antennas, and with a separate from the cooking chamber equipment or technical space in which at least one microwave source is arranged, the antennas are fed via a covered by the accessory line from the microwave source with microwaves of wavelength λ, per treatment level at least one antenna for Microwave radiation is arranged and each treatment level is arranged in a resonator for the microwave radiated into the cooking chamber, which is determined by a food support and the cooking space cover or between two food support; and an accessory with such an antenna structure and a cooking appliance with at least one such accessory.

In the non-pre-published EP 05026912 a generic cooking appliance is described with a microwave generating device, using a likewise generic antenna structure, which largely in a generic accessory of the cooking appliance, such as in the oven of the cooking appliance can be arranged Horden rack, a hooking ladder or the like extends. This antenna structure allows a targeted decoupling of microwaves in different treatment levels for items to be cooked in the cooking chamber, without details of the same are disclosed. However, there is described a coupling and feedthrough system from a microwave conductor outside the oven into a microwave conductor in the oven. The microwave conductors can as Coaxial lines be executed, wherein the microwave conductor in the oven a U-shaped carrier of the accessory as an outer conductor of the coaxial line in which an inner conductor extends, can be guided by the microwaves from the microwave source to all the antennas of an antenna structure may include.

The US 5,334,403 discloses a device for drying, regenerating and thawing having a plurality of treatment levels, each treatment level being associated with a traveling magnetron having at least one antenna. In this case, the antennas can be variably placed between slide-in strips above or below a food item in a treatment level, which leads to a complicated and expensive construction.

Furthermore, from the US 2004/0004074 a Mikrowellengargerät known in which a cooking chamber has several microwave extraction points, which are fed by a microwave source. However, this microwave oven has only one cooking level.

A disadvantage of the above-mentioned prior art is that for a variety of cooking levels or treatment levels food is not easy to feed inexpensive and even microwave energy. For example, the use of a large number of magnetrons consumes a lot of space in a device or technical room of a device. In addition, the synchronization of magnetrons is extremely complicated, especially when a uniform entry of microwave energy in food to be cooked in different treatment levels is desired, since the microwave radiation of different antennas influence each other, e.g. can weaken and possibly reverse.

The present invention is therefore based on the object, the generic antenna structure for a cooking appliance further such that the disadvantages of the prior art are overcome. In particular, an antenna structure for a cooking appliance is to be provided, which enables a uniform energy input into food to be cooked in different treatment levels. In addition, the antenna structure should be as simple and space-saving as possible, save costs, simplify handling and reduce the susceptibility to interference. Finally, the decoupling of microwaves should be as close as possible to a food to be able to treat the food to be targeted.

This object is achieved in that the antennas are designed as detuned λ / 4 rods to act on food in each treatment level with substantially the same microwave energy.

It is preferred that the detuning of radiating into different resonant bodies and can be fed by a microwave source antennas is adapted to the distances of the respective resonator from the microwave source and / or the dimensioning of the respective resonant body.

It can be provided that an antenna is the more detuned, the larger the associated resonant body, and / or an antenna is less detuned, the more antennas are placed between this antenna and the microwave source.

The invention also proposes that the intensity of the detuning of an antenna over its length and / or its diameter is set relative to an optimum λ / 4 antenna, preferably with a plurality of feedable via a microwave source and in each case with different resonance bodies Arranged essentially the same dimension antennas, the antenna, which is arranged in the resonator arranged farthest from the microwave source closest to an optimal λ / 4 antenna.

Furthermore, it can be provided that each antenna is associated with a recess in a waveguide of the line system, and the strength of the detuning of an antenna is set by the surface of the recess.

Preferred embodiments of the invention are characterized in that the waveguide at least in the cooking chamber comprises a coaxial conductor with an inner conductor, in particular in the form of a circular conductor and arranged around it, in particular U-shaped in cross-section outer conductor, which is preferably provided by the accessory includes.

The invention also relates to an accessory for a cooking appliance with an antenna configuration according to the invention, in the form of a tray rack, a rack-mounted trolley or a hooking ladder.

It can be provided that the distances of the food support to each other are substantially equal and the top shelf in the cooking space has a distance from the cooking space, which is greater than the distances of the food support to each other, preferably the length of the fed from a microwave source and different food supports assigned antennas increases with the distance to the microwave source, apart from the top food carrier associated with the antenna.

The invention also proposes that each antenna is spaced apart from the respectively associated food support in order to avoid a short circuit and flashovers, wherein preferably the distances of the antennas to the respective food supports are substantially equal.

Embodiments of the invention are characterized by two in the cooking chamber substantially vertical support, at least one intermediate horizontal support and rails for supporting the Gargutträger, which extend substantially parallel to the horizontal support between the vertical supports.

It can be provided that each waveguide in the cooking chamber comprises a coaxial conductor whose grounded outer conductor are formed by the carriers in which extend the inner conductor.

With the invention, it is again proposed that the antennas each extend substantially perpendicularly from an inner conductor within a vertical carrier substantially parallel to the Gargutträgern and / or rails in the direction of a recess in the inner conductor belonging to the outer conductor or through it.

Furthermore, it can be provided that the microwaves are fed into the oven from below into the accessory.

It is also proposed according to the invention that the accessory with a microwave source via a coupling piece for microwaves is detachable and connectable.

It can be provided that between the inner conductor in a first vertical support and the coupling piece a first switch and / or between the inner conductor in the second vertical support and the coupling piece, a second switch is arranged, wherein preferably the inner conductor is arranged in the horizontal support between the first and the second switch.

With the invention it is also proposed that the coupling piece is connected to one of the two vertical supports, wherein preferably each waveguide of the two vertical supports substantially the same microwave energy can be supplied.

Furthermore, it can be provided that at least one end of at least one vertical support is equipped with a microwave-reflecting end piece, wherein preferably each of the two vertical supports has such a reflective end piece at each of its ends, so that standing waves form in the coaxial lines of the vertical supports ,

It can be provided that between the two reflective end pieces of each vertical support at least one switch and a plurality of antennas are arranged.

Finally, the invention also proposes a cooking appliance with a cooking chamber which is delimited by four side walls, a cooking chamber ceiling and a cooking chamber floor and in which an accessory according to the invention is arranged adjacent to two opposite side walls.

The invention is thus based on the surprising finding that it allows the antenna configuration according to the invention, via a plurality of antennas microwaves of wavelength λ evenly into different superimposed arranged by inserts in a cooking chamber treatment levels in the cooking chamber by a detuning of the antennas in energy radiated by the sound boxes formed by the inserts is adapted to reduce their field strength at each of their extraction points. It is inventively possible that microwaves are fed only at one point in an already necessary for cooking food accessory, so as to realize a space-saving and cost-effective, uniform application of food with microwave energy in each slot.

A special material and space saving results according to the invention, if the antenna structure including the line system is at least partially integrated in carriers or rails and / or posts of the accessory, as already in the non-prepublished EP 05026912 described.

The detuning of the antennas of the individual bays can be achieved in that the length of the antennas deviates from the optimum length of a λ / 4 antenna. It is particularly advantageous for reasons of space saving to detune the antennas by shortening compared to the optimal λ / 4 geometry. In order to ensure as uniform as possible exposure of the individual slots, or better the food arranged thereon, with microwave energy, the radiated at the various antenna positions energy that causes a reduction in field strength in the waveguide of the accessory, be taken to the effect that the same amount of Energy can be emitted from the nth antenna only if a larger percentage of the remaining residual field strength is coupled out of the same. This can be achieved by the length of the n-th antenna being slightly larger than the length of the (n-1) th antenna and thus closer to the optimum antenna geometry of λ / 4.

However, the same effect can be achieved by increasing the thickness of the antennas. An attenuation of the radiated energy can also be achieved by a recess in the microwave (outer) conductor is reduced around the antenna around. All these effects are used according to the invention to influence the energy of the microwave radiated by an antenna.

Also according to the invention, the dimensioning of each resonator in the cooking chamber, which is determined in particular by the distance between two slots to each other to take into account. Namely, if the distance between two slots is large, more modes and polarizations of an antenna radiated microwaves in the limited by the two slots resonance body can be formed so that more energy from the antenna in the resonator preferably on a baking sheet between two slots arranged food is emitted. This is according to the invention by It is taken into account that the length of the antennas in larger resonant bodies is shortened to a greater extent, ie they are more detuned than in the case of the remaining antennas.

Figur 1

eine perspektivische Darstellung eines Zubehörteils für ein Gargerät, ohne Einschubschienen;

Figur 2a

eine Seitenlängsschnittansicht eines Abschnitts des Zubehörteils von Figur 1, jedoch mit einer Einschubschiene, zur Verdeutlichung eines Leitungssystems einer erfindungsgemäßen Antennenstruktur mit Blick auf eine Antenne; und

Figur 2b

eine Querschnittansicht des Leitungssystems von Figur 2a, mit einer Drehung relativ zur Ansicht der Figur 2a um 90° um eine horizontalen Linie.

Further features and advantages of the invention will become apparent by way of example from the following detailed description of preferred embodiments of the invention, with reference to schematic drawings. Showing:

FIG. 1

a perspective view of an accessory for a cooking appliance, without slide rails;

FIG. 2a

a side longitudinal sectional view of a portion of the accessory of Figure 1, but with a slide-in rail, illustrating a line system of an antenna structure according to the invention with respect to an antenna; and

FIG. 2b

a cross-sectional view of the conduit system of Figure 2a, with a rotation relative to the view of Figure 2a by 90 ° about a horizontal line.

In the figures 1 to 2b, an inventive accessory 1 in the form of a hooking ladder with slide rails 10 for baking sheets (not shown) or the like food support and an antenna structure 4 for use in a cooking appliance (not shown). The antenna structure 4 comprises a multiplicity of antennas 4a-4f, 4'a-4'f, which are supplied with microwave energy as follows for the purpose of emitting microwaves of a wavelength λ:

About a Einkopplungsstück 9, in the not pre-published DE 10 2006 007 734.2 is described, microwaves of wavelength λ from a microwave source (not shown) of a switch 7 are supplied. At the switch 7, the corresponding microwave energy is split into two equal parts and then continued via coaxial. In each coaxial conductor, the corresponding microwaves pass along a grounded outer conductor 2 and inner conductor 3 extending therein to connections 6 of the inner conductor 3 to the antennas 4a-4f, 4'a-4'f, which, depending on their size, extend from the inner part 3 to extends to or beyond a recess 5 of the outer conductor 2 out into the cooking chamber of the cooking appliance.

Each of the inner conductor 3 is in a vertical in the installation situation carrier 11, 13 or post or horizontal beam 12 or rail of the accessory, which simultaneously represents the associated outer conductor 2, introduced and formed as a circular conductor to the carrier 11-13 to cooperate to provide a coaxial conductor, as already in the EP 05026912 described. In this case, two vertical support 11, 13 are provided, each representing a grounded shield and the support of rails 10, one of which is shown in Figures 2a and 2b serve. The rails 10 are arranged between the antennas 4 and parallel to them from a vertical support 11 to the other vertical support 13 to carry baking trays in different treatment levels in the cooking chamber of the cooking appliance. The superimposed baking trays determine resonant bodies into which the microwave energy is radiated. Between the two vertical supports 11, 13 a horizontal support 12 is provided in the installation situation, namely for the connection of the two vertical supports 11, 13, which in turn constitutes a grounded outer conductor 2 for an inner conductor 3 guided therein. So that only one of the carriers 11-13 is to be connected to the microwave source via the coupling-in piece 9, the inner conductor of the horizontal carrier 12 extends between two switches 7. In other words, microwave energy passes from the coupling piece 9 into a first switch 7 and from there into The coaxial line of a first vertical support 11 and the coaxial line of the horizontal support 12 via the horizontal support 12 and another switch 7 then again enters microwave energy in the coaxial line of the second vertical support 13. In the end of each of the two vertical support 11, 13 is respectively a reflective end piece 8 is provided which serves to generate a standing wave in the respective coaxial conductor.

Is microwave energy arrived at a compound 6 of the inner conductor 3 with an antenna 4, a portion of this energy for irradiation of microwave along the antenna 4 through the corresponding recess 5 in the outer conductor 2 in the oven between two baking trays or between the cooking chamber and a baking sheet or between a baking tray and the cooking chamber ceiling. The proportion of the radiated energy is determined by the length and the diameter of the antenna 4 and the size of the recess 5 in the outer conductor 2. As a result, for example, in the case of six antennas 4a-4f, 4'a-4'f, only 1/6 of the energy of the microwave at each lowermost antenna 4a or 4'a of each vertical carrier 11, 13 is produced per vertical carrier 11, 13 decouple. The rest of Microwave energy is forwarded to the next antenna 4b or 4'b in each carrier 11, 13, which is a bit longer than the respective lowest antenna 4a, 4'a, so that at this point also 1/5 of the remaining energy of the microwave can be radiated. Thus, the energy of the microwave radiated from the second antenna 4b or 4'b is the same as the radiated energy of the first antenna 4a or 4'a. Since a standing wave is formed in the coaxial conductors 2, 3, at each antenna 4a-4f, 4'a-4'f 1/6 of the microwave energy supplied to each vertical carrier 11, 13 in the illustrated extension of the antennas 4a-4e, 4'a-4'e from bottom to top in the cooking chamber, apart from the respective uppermost antennas 4f and 4'f, are emitted. Because of the large distance between the top trays and baking tray and the Garraumdekke that exceeds the between two bays or baking trays, namely, a plurality of microwave modes of different polarization is allowed to apply the top baking sheet and thus a food arranged thereon (not shown) why the uppermost antennas 4f, 4'f are shortened. The second uppermost antennas 4e, 4'e also preferably represent substantially λ / 4 antennas. In other words, the microwave radiation with which a food to be cooked can be acted upon on a baking sheet between two inserts, for each baking tray, so each treatment level substantially equal.

Figures 2a and 2b show a portion of the left vertical support 11 of the accessory 1 of Figure 1 with a view of a U-shaped recess 5 and an antenna 4, which is perpendicular to the inner conductor 3. The U-shaped recesses 5 extend in a side wall 11 a of the likewise U-shaped support 11 up to the free edge, while at the other edge, the rail 10 is mounted parallel to the antenna 4.

In another embodiment of the accessory according to the invention, the carriers are formed as tubes, so that a waveguide structure is formed in which can be dispensed with an inner conductor. The coupling of microwave can be achieved in such an arrangement by recesses in the tubes, wherein the size of the recesses is adapted to the order and the size of the distances of the bays.

An inventive accessory can be easily removed from the oven and installed in the same by the Einkopplungsstück 9 in a designated Sleeve on the cooking chamber bottom (not shown) is inserted. The coupling of the microwave is done preferably capacitive and / or inductive, so that contamination does not lead to malfunction. Such Einkopplungsstück is not pre-published in the DE 10 2006 007 734.2 described.

Advantageously, a cooking device according to the invention has two antenna structures, namely on two opposite sides of a cooking chamber, which, however, can both be connected to a microwave source via a single coupling and feedthrough system. The distribution of energy can be achieved by switch 7 and / or at least one further coupling piece 9.

The features of the invention disclosed in the foregoing description, in the claims and in the drawings may be essential both individually and in any combination for the realization of the invention in its various embodiments.

LIST OF REFERENCE NUMBERS

1

Accessory / hook-in ladder with antenna structure

2

outer conductor

3

inner conductor

4, 4a-4f, 4'a-4'f

antenna

5

Recess in the outer conductor

6

Connection of the inner conductor with antenna

7a, 7b

switch

8th

reflective tail

9

Einkopplungsstück

10

Rail for insert

11

vertical carrier

11 a

Side wall

12

horizontal carrier

13

vertical carrier

Claims (19)

Antenna configuration for a cooking appliance with a cooking chamber, in which at least one accessory (1) for introducing at least two Gargutträgern in the cooking chamber for the treatment of food on the Gargutträgern in at least two each determined by a Gargutträger treatment levels at least temporarily arranged, the a plurality of Antennas (4, 4a - 4f, 4'a- 4'f) carries, and with a cooking chamber separate equipment or technical space in which at least one microwave source is arranged, wherein the antennas (4, 4a - 4f, 4'a - 4'f) can be fed from the microwave source with microwaves of wavelength λ via a line system encompassed by the accessory (1), at least one antenna (4, 4a-4f, 4'a-4'f) for irradiation of microwaves per treatment plane is arranged and each treatment level is arranged in a resonator for radiated microwave oven in the oven, by a food support and the cooking space cover or between two food support n is fixed, characterized in that
the antennas (4, 4a-4f, 4'a-4'f) are designed as detuned λ / 4-bars, in order to act on food in each treatment level with substantially the same microwave energy. Antenna configuration according to claim 1, characterized in that
the detuning of antennas (4, 4a-4f, 4'a-4'f) which radiate into different resonance bodies and can be fed by a microwave source is adapted to the distances of the respective resonance body from the microwave source and / or the dimensioning of the respective resonance body. Antenna configuration according to claim 2, characterized in that
an antenna (4, 4a-4f, 4'a-4'f) is the more detuned the larger the associated resonant body, and / or an antenna (4, 4a-4f, 4'a-4'f) less is detuned the more antennas are placed between this antenna and the microwave source. Antenna configuration according to one of Claims 1 to 3, characterized in that
the amount of detuning of an antenna (4, 4a-4f, 4'a-4'f) is adjusted along its length and / or diameter relative to an optimal λ / 4 antenna, preferably at a plurality of via a microwave source susceptible antennas (4, 4a-4e, 4'a-4'e), which are each arranged in different resonant bodies with substantially the same dimensions, the antenna (4e, 4'e) which is arranged in the resonance body farthest from the microwave source, closest to an optimal λ / 4 antenna. Antenna configuration according to one of Claims 1 to 4, characterized in that
each antenna (4, 4a - 4f, 4'a- 4'f) is associated with a recess (5) in a waveguide (2) of the ductwork, and the strength of the detuning of an antenna (4, 4a - 4f, 4'a - 4'f) is set by the surface of the recess (5). Antenna configuration according to one of the preceding claims, characterized in that
the waveguide at least in the cooking chamber a coaxial conductor with an inner conductor (3), in particular in the form of a circular conductor, and a arranged around it, in particular U-shaped in cross section outer conductor (2), which is preferably provided by the accessory (1) comprises. An accessory for a cooking appliance with an antenna configuration according to any one of the preceding claims, in the form of a tray rack, a rack-mounted trolley or a hooking ladder (1). Accessory according to claim 7, characterized in that
the distances of the food support to each other are substantially equal and the top shelf in the cooking space has a distance from the cooking space, which is greater than the distances of the food support to each other, preferably the length of the fed from a microwave source and different food supports associated antennas (4, 4a 4f, 4'a-4'f) increases with the distance to the microwave source, apart from the antenna (4f, 4'f) associated with the uppermost food support. Accessory according to claim 7 or 8, characterized in that
each antenna (4, 4a-4f, 4'a-4'f) is spaced from the respectively associated food support for the purpose of avoiding a short circuit and flashovers, the distances of the antennas (4, 4a-4f, 4'a) preferably being 4'f) are substantially equal to the respective food supports. Accessory according to one of claims 7 to 9, characterized by
two in the cooking space substantially vertical support (11, 13), at least one intermediate horizontal support (12) and rails (10) for supporting the food supports, substantially parallel to the horizontal support (12) between the vertical supports (11, 13). Accessory according to claim 10, characterized in that
each waveguide in the cooking chamber comprises a coaxial conductor whose grounded outer conductor (2) are formed by the carriers in which the inner conductors (3) extend. Accessory according to claim 11, characterized in that
the antennas (4, 4a-4f, 4'a-4'f) are each substantially perpendicularly from an inner conductor (3) within a vertical carrier substantially parallel to the food supports and / or rails (10) in the direction of a recess ( 5) in the outer conductor (2) belonging to the inner conductor (3) or extending therethrough. Accessory according to one of claims 7 to 12, characterized in that
the microwaves in the cooking chamber are fed from below into the accessory (1). Accessory according to one of claims 7 to 13, characterized in that
the accessory (1) is detachable and connectable to a microwave source via a microwaveable coupling (9). Accessory according to claim 14, characterized in that
between the inner conductor in a first vertical support (11) and the coupling piece (9) a first switch (7a) and / or between the inner conductor in the second vertical support (13) and the coupling piece (9) a second switch (7b) is arranged, wherein preferably the inner conductor in the horizontal support (12) between the first and the second switch (7a, 7b) is arranged. Accessory according to claim 14 or 15, characterized in that
the coupling-in piece (9) is connected to one of the two vertical supports (11), it being possible for each waveguide of the two vertical supports (11, 13) to be supplied with essentially the same microwave energy. An accessory according to any one of claims 7 to 16, characterized in that at least one end of at least one vertical support (11, 13) is equipped with a microwave reflecting end piece (8), preferably each of the two vertical supports (11, 13) on each has its ends such a reflective end piece (8), so that in the coaxial lines of the vertical support (11, 13) standing waves form. Accessory according to claim 17, characterized in that
between the two reflective end pieces (8) of each vertical support (11, 13) at least one switch (7a, 7b) and a plurality of antennas (4, 4a - 4f, 4'a- 4'f) are arranged. Cooking appliance having a cooking chamber which is delimited by four side walls, a cooking chamber cover and a cooking chamber floor and in which adjacent to two opposite side walls in each case an accessory according to one of claims 7 to 17 is arranged.

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