DE102012006849A1 - Cooking apparatus e.g. combination damper used in e.g. large-scale catering place, has passive chip that is arranged in cooking chamber and provided with chip antenna which is detuned or shielded by each accessory - Google Patents

Abstract

The cooking appliance (10) has a cooking chamber (12) which is arranged with several accessories (20) to contain the food. A passive chip (32) e.g. surface acoustic wave (SAW) or bulk acoustic wave (BAW) chip is arranged in cooking chamber. An antenna (24) transmits and receives the signal with respect to passive chip. The passive chip is arranged with a chip antenna which is detuned or shielded by each accessory. An independent claim is included for a method for detecting loading of cooking apparatus.

Description

The invention relates to a cooking appliance having a cooking chamber in which a plurality of accessories can be arranged, which can carry food, wherein in the cooking space at least one passive chip is arranged, in particular a SAW / BAW chip, and the cooking appliance has an interrogation unit, by means of a Signal can be sent and a response of the chip can be received. The invention further relates to a holder for passive chips and a method for detecting the loading of a cooking appliance having a plurality of insertion levels, can be inserted into the accessories, wherein the insertion levels passive chips are assigned, in particular SAW / BAW chips.

In cooking appliances, which are used in particular for commercial kitchens and for large catering, a holder is arranged in the oven usually (also referred to as Einhängegestell) in which various accessories can be added in several levels, such as a rack, a baking sheet, a grill plate or a Rust. For automated, optimal control of each selected cooking process, it is desirable that it can be automatically detected how many accessories are located inside the cooking chamber and in which rack level. If the controller of the cooking appliance is aware that, for example, the cooking appliance has been charged with a large amount of accessories and thus food to be cooked, the respective cooking program can be operated with different process parameters than with a feed of only a small amount of food.

From the DE 43 24 015 C1 Accordingly, a so-called load indicator is known, with the automatic can be detected in which of the bays of a Einhängegestells an accessory is inserted. For this purpose, mechanical switches or photocells are provided on the suspension rack.

From the DE 10 2008 031 378 A1 a cooking appliance is known which uses RFID tags for insertion identification, which can be attached to the food storage container, for example. To detect the RFID tags, RFID antennas are provided in the interior of the cooking appliance.

All these solutions have in common that they require a relatively high effort. Mechanical switches or light barriers on the hanger rack require the hanger rack to be wired and provide a reliable electrical connection with a controller of the cooking appliance. RFID tags require a lot of effort regarding the provided in the cooking chamber of the cooking device antennas, so that all RFID tags can be read reliably.

The object of the invention is to enable a reliable load detection with less effort.

To achieve this object, the invention provides for a cooking appliance and a holder of the type mentioned above, that the antenna of the chip is arranged so that it can be detuned by an accessory or shielded. In a method of the aforementioned type, it is provided that all chips are interrogated simultaneously and an accessory is recognized by the fact that no or only a very weak response can be received by the chip associated with the corresponding insertion level. The invention is based on the basic idea to go exactly the opposite way for the purpose of load detection as in the prior art, when there are chips, such as RFID tags, queried to detect the presence of an accessory. In the prior art, a great deal of effort has to be made to reliably ensure, with all possible configurations of accessories inside the cooking chamber of the cooking appliance, that all the chips can be reliably read out. According to the invention, the accessories to be used are then used to change or worsen the reception properties with regard to the chip assigned to the corresponding insertion level such that the chip sends no or only a weak response signal when it is interrogated. The invention builds on the knowledge that it is structurally much easier to detune or shield the antenna of a chip with an accessory than that it can be ensured that, regardless of the type and number of accessories located in the cooking chamber all Chips can be reliably queried. This is especially true because the chips can be fixedly mounted on the suspension rack or other suitable locations in the cooking chamber so that there is no optimal feeding or receiving position to the polling antenna or the polling antenna without loading. The positioning of the chips in the cooking chamber also has the advantage that standard accessories can be used in most embodiments.

According to one embodiment of the invention, it is provided that the interrogation unit has a interrogation antenna, which is arranged so that the antenna of the chip lies with the accessory inserted in the shielding shade of the accessory. In this embodiment, it is exploited that many of the accessories are solid, plate-shaped metal components that can be used excellently for shielding electromagnetic radiation.

Preferably, it is provided that the antenna is arranged by a defined by the insertion rail insertion level at a distance which is small compared to the wavelength of the frequency with which the chips are queried. This embodiment is based on the physical effect that an electromagnetic wave impinging on an electrically conductive wall is reflected by it and forms a standing wave in front of the wall, wherein the wall is a node of the electric field strength. The antenna is now close to the electrically conductive wall, which is specifically formed here by an inserted accessory such as a grill plate or a baking sheet, the antenna of the chip can hardly receive electromagnetic radiation. This effect is particularly pronounced when the antenna is at a distance from the accessory that is less than or equal to one tenth the wavelength of the radiation used to interrogate the chips.

Preferably, it is provided in the cooking appliance or on the holder that this distance is smaller than 2 cm and in particular smaller than 1.2 cm. In this way, the electromagnetic radiation typically used to interrogate the chips, which has a wavelength of the order of 12 cm, can reliably ensure that the antenna of the chip can no longer be interrogated after the accessory has been inserted.

It can also be provided that the antenna is assigned a shielding plate, so that it lies with the accessory inserted in a narrow gap between the shielding plate and the accessory. The term "narrow gap" is understood to mean that the thickness of the gap is less than half the wavelength of the electromagnetic radiation used to interrogate the chips. In such a gap between two electrically conductive walls, which are formed here by the shield and the inserted accessory, electromagnetic radiation can not penetrate sufficiently far to query the chip can.

According to one embodiment of the invention it is provided that the insertion rail is associated with a pair of chips with mutually perpendicular antennas. With this configuration, in which one antenna is aligned parallel to the plane defined by the grid and the other perpendicular to this plane, it is possible to recognize different types of accessories. If both chips can not be queried, it can be concluded that a solid, plate-shaped accessory is inserted. If, on the other hand, only one of the chips can be interrogated, but not the other, it can be concluded that the inserted accessory is a rust. Namely, electromagnetic oscillations oriented perpendicular to the plane defined by the grate can easily be received by one of the two chips, while vibrations oriented parallel to the grate can not be received by the other antenna.

According to one embodiment of the invention, it is provided that an insertion rail two chips are assigned at a distance from each other, in particular in the region of the front and the rear end of the corresponding insertion rail. This makes it possible to distinguish different depths accessories from each other. If only one of the chips is no longer interrogatable, it is an accessory with a shallow depth. If both chips are no longer interrogatable, it is a deep accessory.

In another embodiment, the positions of the chips and special accessories are matched to one another such that the accessory has modifications that merely shield or detune reception for particular chips provided therefor. Such modifications can be used to distinguish accessories that would otherwise be indistinguishable.

The various configurations can also be combined.

In order to be able to differentiate between different chip levels, it is preferably provided that a set of chips having a decoded coded ID is used, the chips used being selected from the number space such that a simultaneous ID of all chips is obtained. Common chips use a decimal coded ID, usually in the 0 to 9999 range. If, for example, the chips with the numbers 1 and 11 were in the cooking chamber, it would not be possible to distinguish whether only the chip with the number 11 or additionally the chip with the number 1 is in the cooking chamber, since the response signal received by the interrogation unit is a "1 "At the one-digit of the response signal, which can come from both the chip with the ID 0001 and the chip with the ID = 0011. For this reason, it is useful to use the chips with the ID of 0000 to 0009, chips with a tens digit of 1 to 9 and a unit digit of 0 (that is, 0010, 0020, 0030,... 0090), chips having a hundredth place of 1 to 9 and a tens and a unit of 0 (ie 0100, 0200, 0300, ... 0900) and chips with a thousandth place from 1 to 9 with a hundred, ten and one digit from 0 (ie 1000, 2000, 3000 , ... 9000) used. With this selection of chips, 37 different chips can be interrogated simultaneously and recognized unambiguously (if they return a response signal). From the missing response signals can be close at which point an accessory is located in the cooking chamber.

As an alternative to coding with 4 decimal digits, a coding in the dual system can be used in which each bit is assigned to a specific chip. In general, many reflectors per chip would be necessary, but not here, since each chip sends only one specific bit. A special design could be used to get as many as possible readable IDs.

The invention will be described below with reference to various embodiments, which are illustrated in the accompanying drawings. In the drawings show:

1 in a schematic sectional view of an inventive cooking appliance;

2 in a perspective view of a holder, the cooking device of 1 can be used with inserted therein accessories;

3 schematically a first variant of the attachment of chips to a slide rail;

4 schematically a second variant;

5 schematically a third variant; and

6 schematically a fourth variant.

In 1 is schematically a cooking appliance 10 shown, which is intended for professional use in commercial kitchens and large catering. It may be, for example, a combi steamer that can prepare different food with hot air and / or superheated steam. The corresponding cooking processes preferably run automatically depending on the particular food to be cooked, the desired final state and also of the loading of the cooking appliance. Those components of the cooking appliance such as a steam generator, a fan, a control unit, etc., which are not required for understanding the invention are not shown here.

The cooking appliance 10 contains a cooking space 12 which is accessible via a door (not shown). Inside the cooking chamber 12 there is a holder 14 , which is also known as a hanging rack, as it is mounted in Einhängegestaltungen inside the cooking chamber. The holder consists of a plurality of substantially vertically extending support rods 16 and a plurality of substantially vertically extending insertion rails 18 , each on two support bars 16 are attached and pairwise together define a shelf level. The shelf levels are in 1 denoted by E1, E2, ... E9. The slide rails 18 are designed as a profile part and can have different cross sections depending on the requirement. It is crucial that the slide rails 18 different accessories 20 can be inserted. The accessories can generally be food carriers, for example a baking tray, a cooking tray, a grill plate, a pizza plate, a grid, etc., on which food is to be cooked 22 located.

The cooking appliance 10 is with a polling antenna 24 provided here on a side wall 26 of the cooking chamber 12 is arranged. In principle, it is possible to use more than one antenna in the oven. Also, the polling antenna does not necessarily have to be on the sidewall 26 of the cooking chamber 12 but may also be arranged on the door of the cooking appliance, for example in the form of wire loops in a door glazing, or the interrogation antenna may be on the back wall, ceiling or bottom of the cooking chamber 12 to be placed.

The antennas 24 which are part of an interrogation unit serve to send an interrogation signal and receive a response signal. The radio signals used for the interrogation signal may have a wavelength of the order of 12 cm. Depending on the frequency ranges that are released for such radio signals in different countries, however, deviations may arise here. The response signal is from an evaluation unit 28 evaluated, which is also part of the query unit and with a controller 30 of the cooking appliance 10 communicates. The controller is responsible for the cooking processes that take place in the cooking appliance 10 can expire. It is understood that the evaluation unit 28 and the controller 30 implemented as part of a software.

That from the polling antennas 24 received response signal comes from passive chips 32 , which are located inside the cooking chamber. Particularly suitable for the passive chips are SAW / BAW chips, which can be read out without contact. For this purpose, an interrogation signal is sent to the chip (comparable to radar technology), and the chip reflects a response signal that can be evaluated. A SAW chip is a special embodiment that works with surface acoustic waves (SAW). Such a chip contains in each case an antenna, a transducer and a reflector structure. The transducer converts an electromagnetic wave received via the antenna, the interrogation signal, into a surface acoustic wave propagating on the piezoelectric material from which the SAW chip is formed. The surface wave is reflected by the reflector structure, wherein at the same time a coding takes place. The coding is in particular a unique identification number. The reflected signal is converted by the converter again, so that a response signal can be sent back from the antenna. A BAW chip operates essentially in the same way, in which case no surface waves are used, but wave propagation takes place inside the material (BAW = bulk acoustic wave).

In principle, other passive chips can be used, which can be interrogated contactless by means of electromagnetic radiation.

The chips 32 are in the embodiments shown in the figures on the slide rails 18 of the hanging rack 14 appropriate. In this case, preferably, each insertion rail 18 with at least one chip 32 Mistake. As in 2 is shown, the chips can be either about the middle of a slide rail 18 be attached, or it can per slide rail 18 two chips 32 be used, one of which is located near the front end and the other in the vicinity of the rear end. If there are two chips on a slide rail 32 can be used, it can be detected whether in the corresponding slide rail is an accessory with shallow depth or with great depth; in the first case, only one of the two chips can be queried successfully, while in the second case, neither of the two chips can be queried.

In principle, it is also possible not to attach the chips directly to the suspension rack, but to fix it elsewhere in the cooking chamber so that a suitable fixed position results relative to accessories, which can be inserted into the slide rails. For example, the chips can be mounted on a separate holding device, which is mounted independently of the suspension rack in the cooking chamber (for example, as a retrofit) and which positions the chips or their antennas in a suitable location, so that they are influenced in the desired manner by the accessories. The holding device can be arranged in the vicinity of the suspension rack or in the vicinity of the rear wall between the Einhängegestellen.

Thus, it should be taken into account that the chips 32 even if they are below as on the slide rails 18 attached may be attached in the same way to a separate holder.

In 3 schematically is a first embodiment with a chip 32 shown, whose ID can be read when in his assigned slide rail 18 no accessory is located, whereas an accessory in the slide rail prevents the chip from being interrogated.

Schematically represented is one of the slide rails 18 to which the chip can be attached. In the exemplary embodiment shown here, the insertion rail has a recess 40 on, below which the chip 32 is arranged, in particular so that its antenna 42 in the region of the recess 40 lies. When in the slide rail 18 no accessory 20 is located, the antenna can 42 receive an interrogation signal from the polling unit via the polling antenna 24 can be sent out. In response to the interrogation signal, the chip sends 32 a response signal, which can consist here in particular of its ID. If, however, the accessory 20 located in the slide rail, it means that near the antenna 42 of the chip 32 a comparatively solid metal component is located. This can have different physical effects depending on the respective geometric conditions in the cooking chamber and on the insertion rail.

An effect may be that when the accessory is inserted 20 the antenna 42 located in the shade of the accessory, since such a sheet metal component shields electromagnetic radiation.

Another reason that the chip 32 can no longer be queried if an accessory 20 in the corresponding slide rail 18 may be that the accessory 20 As an electrically conductive body in the vicinity of the antenna, the capacitance of the electrical resonant circuit formed by the antenna changes. It is advantageous that the largest possible capacity arises to the antenna, depending on their design, for example, in particular to the tips. As a result, the resonant frequency of the antenna no longer coincides with the frequency of the interrogation signal. The chip can therefore no longer receive the interrogation signal and accordingly no longer send a response signal. For this effect, usually a narrow-band antenna is advantageous, ie an antenna which has a good reception power only in a narrow frequency band.

A third effect of the accessory 20 may be that it acts as an electrically conductive wall, which is a zero of the exciting field (Node). Also in this case the antenna can 42 the interrogation signal is not or only insufficiently received. This effect is due to the fact that when a plate-shaped accessory 20 the electric field parallel to the plate surface in the vicinity the plate disappears, ie at a distance which is small compared to λ / 4. If the electric field of the vibrating antenna vibrates substantially parallel to the plate, it can no longer receive. Particularly pronounced is this effect when the distance A between the antenna 42 and the wall, so the accessory 20 , small compared to the frequency used for the interrogation signal, in particular less than one tenth of the wavelength. Since the frequencies commonly used to interrogate SAW / BAW chips have a wavelength of around 12 cm, so should the distance between the antenna 42 and the accessory 20 maximum on the order of 12 mm.

In 4 a second embodiment is shown. For the components known from the preceding embodiment, the same reference numerals are used, and reference is made in this regard to the above explanations.

In the embodiment according to 4 is the chip 32 an additional metallic wall in the form of a shielding plate 50 assigned. When in the slide rail 18 an accessory 20 is located, lies the chip 32 between two parallel, electrically conductive walls. The distance B of these walls from each other is chosen smaller than λ / 2, so that the electromagnetic wave is in the gap between the shield 50 and the accessory 20 can not spread. Thus, also the antenna of the chip 32 receive no interrogation signal anymore.

In 5 a further embodiment is shown. As an accessory 20 a rust is used here. To distinguish a rust from a plate, two chips are used 32 used, whose antennas are oriented differently. This is in 5 schematically indicated by the fact that the antenna of the left chip 32 (Shown as a short piece of wire protruding from the housing of the chip) is arranged parallel to the bars of the grate and the antenna of the right chip 32 is arranged perpendicular to the bars of the grate. If it is the accessory 20 is a rust, one of the two chips can not be queried. The chip whose antenna is aligned to receive the radiation aligned parallel to the grate will not receive an interrogation signal here while that one whose antenna is aligned to receive the radiation which oscillates perpendicular to the grate will receive and respond to the interrogation signal becomes.

In 6 a fourth embodiment is shown, which is based on a different operating principle. In the embodiment according to 6 the accessory (at least not primarily) acts on the antenna of the chip 32 but changes the load impedance.

In 6 is schematically a converter 60 shown that (in the case of a SAW chip) a surface wave 62 which was generated in response to an interrogation signal coming from the antenna 42 was received. The converter 60 is a first, fixed plate 64 associated with metal. If the accessory 20 is inserted, is the converter 60 between two electrically conductive plates, so that there changes the capacity compared to a state without an accessory. This also changes the load impedance, resulting in a change in the RF response of the SAW chip.

For load detection, the interrogation unit can detect whether the response signal corresponds to a state with normal load impedance, with the result that no accessory is present in the corresponding slide rail, or if the chip 32 was detuned by the changed load impedance. If a narrowband antenna is used, it can be tuned to the chip so that it can only transmit the response signal at "normal" load impedance, whereas no (or only a very weak) interrogation signal can be sent with a changed load impedance, ie detuned chip , In this respect, a very bad response signal from the interrogation unit in the same way as the case that no response signal is received.

As already mentioned above, as an alternative to attachment to the rails of the suspension rack, the chips can also be arranged only in the vicinity of the rails. For example, the chips can be arranged at the end of a rail. It is also possible to arrange the chips below a rail so that they lie in the vicinity of the side wall of the container in deep containers, which are inserted as an accessory. The dipole antenna is arranged parallel to the container wall or vertically (capacitive detuning). Furthermore, it is possible to arrange the chips above a rail with the dipole antenna downwards, that is directed towards a possibly inserted metal sheet. The splint should then not be too close or must be cut out.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4324015 C1 [0003]
• DE 102008031378 A1 [0004]

Claims (10)

Cooking appliance ( 10 ) with a cooking space ( 12 ), in which several accessories ( 20 ) can be arranged, which can carry food, wherein in the cooking chamber ( 12 ) at least one passive chip ( 32 ), in particular a SAW / BAW chip, and the cooking appliance ( 10 ) an interrogation unit ( 24 . 28 ), by means of which a signal is sent and a response of the chip ( 32 ), characterized in that the antenna ( 42 ) of the chip ( 32 ) is arranged so that it by an accessory ( 20 ) can be detuned or screened. Cooking device according to claim 1, characterized in that the interrogation unit is a polling antenna ( 24 ), which is arranged so that the antenna ( 42 ) of the chip ( 32 ) with the accessory ( 20 ) lies in the shade of the accessory. Bracket ( 14 ) for passive chips ( 32 ) for a cooking appliance according to claim 1 or claim 2, provided with or arranged in the vicinity of a plurality of slide rails, can be inserted into the accessories, wherein on the holder in each case at least one passive chip ( 32 ), in particular a SAW / BAW chip, is arranged such that the antenna ( 42 ) of the chip ( 32 ) by an accessory ( 20 ) can be detuned or screened. Holder according to claim 3, characterized in that the antenna ( 42 ) of one of the slide rails ( 18 ) defined at a distance (A) which is small compared to the wavelength of the frequency with which the chips ( 32 ). Holder according to claim 3 or claim 4, characterized in that the distance is smaller than 2 cm. Holder according to one of claims 3 to 5, characterized in that the antenna ( 42 ) a shielding plate ( 50 ) so that when the accessory is inserted ( 20 ) in a narrow gap between the shielding plate ( 50 ) and the accessory ( 20 ) lies. Holder according to one of claims 3 to 6, characterized in that the insertion rail ( 18 ) a pair of chips with perpendicularly oriented antennas ( 42 ) assigned. Holder according to one of claims 3 to 7, characterized in that a slide rail ( 18 ) two chips ( 32 ) are assigned at a distance from each other. Method for detecting the loading of a cooking appliance ( 10 ), which has several levels of insertion (E1, E2, .., E9), into the accessories ( 20 ) can be inserted, wherein the insertion levels passive chip ( 32 ), in particular SAW / BAW chips, characterized in that all the chips ( 32 ) and an accessory ( 20 ) is recognized by the fact that from the corresponding rack level (E1, E2, ... E9) associated chip ( 32 ) no or only a very weak answer is received. Method according to claim 9, characterized in that a set of chips ( 32 ), which has a decimal coded ID, whereby the chips used ( 32 ) are selected from the number space such that when all the chips are queried simultaneously ( 32 ) gives a unique ID.

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