FOOD PREPARATION DEVICE

Description

[0001] The present invention relates to a device for preparing food, comprising a housing and a preparation chamber inside the housing which is intended and configured to receive food to be prepared therein, an access door for opening and closing an access door opening to the preparation chamber, a heating element which is intended and configured to apply and maintain an increased temperature in the preparation chamber, at least first air displacing means which are intended and configured to generate a forced airflow and carry it over the heating element in order to spread heat generated by the heating element over the preparation chamber, and electronic control means which are intended and configured to control one or more functions of the device, wherein the housing comprises a further chamber, separated from the preparation chamber, in which the control means are at least partially accommodated.

[0002] The invention relates here particularly to a combi-steamer, i.e. a steam oven in which a food product is prepared or finished at increased temperature and under the influence of steam so that it is ready for consumption. Such a device is for instance known from European patent application EP 0 089 025 A1. Described therein is a steam oven in the form of a cabinet-like housing in which a preparation chamber is accommodated. Situated in the preparation chamber is a fan with a heating element therein for heating the air flowing therethrough. During operation, the fan generates a forced hot airflow in the preparation chamber, which is guided via the walls of the preparation chamber. This results in a particularly homogeneous temperature distribution in the preparation chamber, which enhances the preparation of a product to be prepared therein and allows multiple products simultaneously at different levels. This known apparatus furthermore comprises a steam generator which produces hot steam during operation and lets it into the preparation chamber via an inlet provided close to the fan for this purpose.

[0003] Such an apparatus is usually applied as an oven, wherein a temperature of typically more than a hundred or even more than two hundred degrees Celsius is applied in the preparation chamber. From a viewpoint of safety of the surrounding area, a similar temperature increase of the outer casing of the housing of the device is undesirable. In order to prevent this, and otherwise also from a viewpoint of energy saving, the outer walls of the device are usually thermally insulated. This however means that the heat is trapped in the device and that this may cause electronic components forming part of the control device to become hot, which, in extreme cases, may result in overheating. Opening of the access door must also be done with the necessary caution. As a result of the steam generation, a certain overpressure prevails in the preparation chamber, whereby hot steam will exit as soon as the access door is opened.

[0004] DE 10 2019 205 337 A1 and FR 2726633 A1 disclose further prior art devices for preparing food.

[0005] The present invention has for its object, among others, to provide a device for preparing food at increased ambient temperature, wherein the above described dilemma and danger are obviated to at least significant extent.

[0006] The invention is defined by the device according to claim 1. Preferred embodiments are defined in the dependent claims.

[0007] In order to achieve the stated object a device of the type stated in the preamble has the feature according to the invention that the housing comprises outside the preparation chamber in heat-exchanging contact with the chamber an air channel which is separated at least vapour-tightly from the chamber, that further air displacing means are provided for generating and maintaining a further airflow in the air channel, and that the air channel comprises adjacently of the access door opening an air inlet for the further airflow.

[0008] The invention thus provides further air displacing means, particularly in the form of a further fan, for generating and maintaining a cooling airflow which is drawn in from outside the apparatus and which is brought into heat-exchanging contact with the further chamber in which the control electronics are concealed. These parts of the device are hereby able to relinquish heat to this airflow and so carry it away out of the device. This results in an active cooling of the further chamber in which the electronics are accommodated.

[0009] Because the inlet of the further air channel is situated adjacently of the access door, an effective extraction can thereby also be provided as soon as the access door is opened, whereby hot air and / or steam which escapes then is extracted in effective manner, which provides additional safety particularly in the case of a combi-steamer. The vapour-tight separation between the air channel as the chamber with control electronics ensures that any steam and / or moisture carried away here cannot penetrate to the electronics which are usually vulnerable thereto. In this way the invention provides with the further airflow not only an effective cooling of the control, but also an effective extraction of the preparation chamber when the access door is opened.

[0010] The air inlet comprises adjacently of the access door opening an air gap which extends along at least substantially a whole side of the access door. An extraction is thus generated on at least one side of the access door, over almost a whole height or width of the access door opening, when the access door opens. At least one side where the access door moves away from the housing is preferably selected for this purpose, such as particularly a side remote from a hinge side in the case of a swing door.

[0011] The access door is double-walled, comprising a first wall and a second wall which extend at least substantially parallel to each other and maintain here a cavity relative to each other, and the air inlet is in open communication with the cavity. Use is here made of a double-walled access door which is itself already thermally insulating owing to the cavity formed therein. Owing to the open communication between the air inlet and the cavity between the two walls of the access door, the cooling airflow will furthermore be drawn through the cavity, whereby the access door is likewise actively cooled. This results in a particularly effective cooling of the access door. In practice all this can be dimensioned such that the access door does not become any hotter than lukewarm on the outside, and thereby remains completely safe. This is particularly desirable from a viewpoint of user safety. A particular embodiment of the device according to the invention has the feature here that the first wall and the second wall each comprise an at least partially transparent window in order to moreover give the user a continuous view of the preparation process taking place in the preparation chamber.

[0012] The air inlet connects at least substantially airtightly to the cavity in the access door in a closed position of the access door, and the cavity opens onto a surrounding area on an opposite side. The at least substantially airtight connection avoids false air from being drawn in and thus enhances an effective airflow via the cavity. The fresh ambient air which is here drawn in from outside upstream of the air inlet will here firstly provide for a cooling of the access door, which is preferable from a safety perspective.

[0013] According to the invention, particularly in the form of a combi-steamer, steam means are provided therein for generating a stream-air mixture in the preparation chamber. According to an embodiment, the preparation chamber is provided with a steam discharge for evacuating an excess of the steam-air mixture from the preparation chamber, and that the housing comprises a further air channel for carrying a further airflow in heat-exchanging contact with at least a part of the steam discharge. A further airflow can here be guided over the steam discharge via the further air channel for the purpose of an active cooling of the part of the steam-air mixture escaping from the preparation chamber. This enhances condensation thereof, whereby a water buffer in the apparatus can optionally be replenished, and furthermore prevents steam from being blown out of the device.

[0014] A further particular embodiment of the device has the feature here that the further air displacing means are also able and configured to generate and maintain the further airflow in the further air channel. The further air displacing means are thus utilized not only for one or more of cooling of the access door, extraction of hot air and / or steam at the edge of the opened access door and the control electronics, but also to maintain the further airflow over the steam discharge.

[0015] A further preferred embodiment of the device has the feature here that the steam discharge comprises a condenser in heat-exchanging contact with the further air channel, that the preparation chamber is provided with a liquid discharge, and that the condenser comprises a condensation discharge which debouches in the liquid discharge of the preparation chamber. Condensation which was separated by the condenser is thus discharged via the liquid discharge which is already present for evacuation of any moisture and cleaning agents from the preparation chamber.

[0016] In a further preferred embodiment the device according to the invention is characterized here in that the liquid discharge comprises a water trap and that the condensation discharge debouches upstream of the water trap in the liquid discharge. Although liquid can freely pass the water trap, steam or hot air is met with a counterpressure which is determined by a water column in the water trap. The water trap thus builds up a barrier to steam during operation, so that this steam cannot escape via the liquid discharge. The condensation discharge to the water trap ensures that this water column is replenished, i.e. refilled, continuously and thereby that this barrier is maintained, without a fixed water connection or similar water supply from outside being required for this purpose. The device according to the invention can therefore advantageously be applied as autonomous stand-alone apparatus with only an electrical connection.

[0017] Although for the further air displacing means separate fans can in each case be applied in each air channel outside the preparation chamber in order to provide for an airflow therein, a further preferred embodiment of the device according to the invention has the feature that the further air displacing means comprise a collective fan which is able and configured to generate and maintain separate airflows in a number of air channels outside the preparation chamber during operation. This results in a significant saving in the number of components in the device, and a corresponding amount of space is saved in the apparatus.

[0018] The invention will be further elucidated hereinbelow with reference to an exemplary embodiment and an accompanying drawing. In the drawing: Figure 1is a cross-sectional view of an exemplary embodiment of a device according to the invention with an access door in a closed position; Figure 2is a cross-sectional view of the device of figure 1 with the access door in opened position; and Figure 3is a rear view of the apparatus of figure 1.

[0019] It should otherwise be noted that the figures are purely schematic and not always drawn to (the same) scale. Some dimensions in particular may be exaggerated to greater or lesser extent for the sake of clarity. Corresponding parts are designated in the figures with the same reference numeral.

[0020] The device shown in figure 1 comprises a so-called combi-steamer for preparing food, particularly meals, also including finishing and heating of dishes and meals which were already cooked previously, also referred to as regeneration. The device comprises an apparatus enclosed by an outer casing 10 and housing a preparation chamber 20 and a further chamber 30 in which are accommodated inter alia control electronics 35 (not shown in the figure) for a control device of the apparatus. The preparation chamber 20 is accessible via an access door 40 provided for this purpose, which in this case takes a double-walled form and comprises a transparent inner window 41 and an outer window 42, mutually separated by a hollow cavity 43.

[0021] Situated in the preparation chamber 20 are heating means in the form of an electrical heating element 21 which is controlled thermostatically by the control electronics 35 and so imposes a set preparation temperature in the preparation chamber. Air displacing means in the form of a fan 22 disposed at the heating element 21 serve for distribution of heat through the preparation chamber 20. The heating element 21 and the fan 22 are separated from the remaining part of the preparation chamber 20, also referred to hereinafter as the oven space, by a fan grating 25, also referred to as vent plate, which introduces a certain air resistance and thereby provides for a better distribution over a width and height of the oven space 20 of an airflow forced through fan 22. The fan grating 25 maintains a recess 24 to the inner walls of oven space 20 all around in order to provide a circulation of the airflow over the walls of oven space 20 and then back to fan 22 again.

[0022] The preparation chamber further comprises a water inlet 23 whereby water can be let in during operation. When preparing food in preparation chamber 20, steam is created in that water is introduced via the water inlet 23 into the preparation chamber 20 and is drawn in by fan 22. Water here comes into contact with the heating element 21, whereby steam is created. This steam is then entrained by the hot airflow and thus finds its way into preparation chamber 20. The water inlet 23 thus forms part of steam means which additionally comprise a water connection and feed conduit with pump and (scale) filter 29, see figure 3, to the water inlet 23. With a view to a more autonomous stand-alone setup a refillable water reservoir can instead also be used as steam source in the apparatus. The steam means are also controlled by the control device 35.

[0023] According to the present invention, the appliance comprises outside the preparation chamber 20 further air displacing means in the form of a further fan 60. In contrast to the fan 22 in preparation chamber 20, this second fan 60 maintains a cooling airflow L1, L2 which is continuously drawn in from outside. For this purpose the fan 60 is connected to a first air channel 61 in the apparatus, through which a first airflow of cool outside air is drawn in. This air channel 61 extends along substantially a whole surface of a metal bottom of the chamber 30, extending thereunder, and is separated therefrom vapour-tightly in order to avoid this airflow from entering chamber 30. An active cooling of electronics 35 and remaining components inside chamber 30 is thus achieved by the heat-exchanging contact which takes place thereby between the airflow L1 and the content of chamber 30.

[0024] The first air channel 61 is fed from an air inlet 62 in the form of a narrow gap extending above the access door 40 over practically a whole door width along the apparatus door opening of apparatus housing 10. When access door 40 is closed (see figure 1), the air inlet 62 here connects closely to an open outer end of the cavity 43 in the access door and is thus in open communication with the cavity 43. At an opposite outer end the cavity 43 opens over practically a whole width onto an open intermediate space 63 relative to the adjacent part of the housing 10. The cavity 43 is here thus in open communication with the surrounding area and so provides for a possible intake of fresh, cool outside air if access door 40 is closed. The second fan 60 draws the cool outside air through the cavity 43 of the access door 40, which takes a dual form. With this airflow L1 the fan 60 maintains active cooling of access door 40, particularly the outer window 42 thereof, during operation.

[0025] When access door 40 is opened, see figure 2, fan 60 remains operational, whereby an underpressure continues to prevail at the inlet 62 of air channel 61. The steam S, which is now able to escape preparation chamber 20, will hereby be drawn in at the inlet 62 of air channel 61. A speed of the fan 60 can here optionally be increased for a powerful extraction, which prevents steam from exiting the apparatus on the front side. Instead, steam is now carried away to the rear via the air channel 61 and the fan 60. In channel 61 the steam will evaporate almost entirely above preparation chamber 20 and leave the apparatus as water vapour on the rear side. The vapour-tight separation between air channel 61 and control chamber 30 prevents steam or water vapour from being able to penetrate to the electronics 35 which are vulnerable thereto. Dehumidifying means, such as for instance an (additional) condenser, can optionally be provided in or downstream of the air channel 61 in order to ensure that only dry air leaves the device on the rear side of the apparatus. These means can be provided in the apparatus both upstream and downstream of the fan 60, but can for instance also be arranged externally of the housing in the form of an additional module on the outlet 65.

[0026] On a rear side the apparatus has a second air inlet 67 for cool air from the surrounding area. This second air inlet 67 debouches in a second air channel 66, into which a second cooling airflow L2 is drawn by fan 60. This second airflow L2 is carried more or less directly over the heat exchanger 55 of the condensation tube 51, or at least brought into heat-exchanging contact therewith. The condensation tube 51 thereby functions all the more effectively as condenser for enhancing condensation of substantially all steam escaping from the preparation chamber. Downstream of fan 60, the two cool airflows L1, L2 find their way to a shared air outlet 65 on a rear side of the apparatus.

[0027] Situated at the bottom of the oven space is a liquid discharge for collecting excess moisture, such as for instance drip water, condensation and / or cleaning agent, but also greases, crumbs and any other food residues. The liquid discharge comprises here a discharge opening 26 in a bottom plate of the preparation chamber 20 through which steam can also escape. Provided downstream of and somewhat below the bottom plate of the preparation chamber is a water trap 27. Condensation and other liquid running off via the discharge opening can freely pass the water trap 27. Steam from the preparation chamber is however stopped by the water trap and can only move via the condensation tube 51. Present in the apparatus downstream of water trap 27 is a removable reservoir 28 in which this moisture is collected together with any residues entrained therein. A coupling can optionally also be provided here for connection to a fixed water discharge at the apparatus.

[0028] Water trap 27 offers a barrier to steam escaping oven space 20 via discharge opening 26. Water trap 27 thereby provides for a slight overpressure in preparation chamber 20, which is determined by a height of a water column in the water trap. Steam thereby rises in a steam discharge with a condenser in the form of a condensation tube 51. The condensation tube 51 has a wall of aluminium and is surrounded by a heat exchanger 55 which provides for an adequate cooling and heat discharge. Steam will thereby precipitate almost wholly in the form of condensation in condensation tube 51. Any remaining, uncondensed steam can leave the apparatus on the rear side via a steam outlet 52, see figure 3, provided for this purpose. In contrast, steam condensed onto he wall of condensation tube 51 (condensation) runs downward therealong and is carried away via water trap 27 to collecting reservoir 28. Water trap 27 is thus continuously replenished, i.e. the level thereof is maintained.

[0029] Although the invention has been further elucidated above with reference to only a single exemplary embodiment, it will be apparent that the invention is by no means limited thereto. On the contrary, many variations and embodiments are still possible within the scope of the invention for a person with ordinary skill in the art. In the example use is thus made of a combi-steamer oven, but the invention can also be applied in fan ovens without steam feature. In addition to or instead of a convection-based heating element, as in the example, use can likewise be made of different types of heating means, such as for instance on the basis of microwaves or infrared lamps.

[0030] Besides baking in hot air, use can further also be made of a preparation process on the basis of deep-frying in hot air, as for instance also applied in consumer products referred to as Air Fryers ®< . The invention generally provides an additional cool air flow outside the preparation chamber for cooling control electronics thereby, wherein this airflow outside the preparation chamber can also be utilized for one or more other purposes, such as for instance cooling of an access door or cooling of a condenser for excess steam. The scope of the invention is defined in the appended claims.

Claims

1. Device for preparing food, particularly a combi-steamer, comprising a housing (10) and a preparation chamber (20) inside the housing which is intended and configured to receive food to be prepared therein, an access door (40) for opening and closing an access door opening to the preparation chamber, a heating element (21) which is intended and configured to apply anc maintain an increased temperature in the preparation chamber, at least first air displacing means which are intended and configured to generate a forced airflow and carry it over the heating element in order to spread heat generated by the heating element over the preparation chamber, and electronic control means (35) which are intended and configured tc control one or more functions of the device, wherein the housing comprises a further chamber (30), separated from the preparation chamber, in which the control means are at least partially accommodated, wherein the housing comprises outside the preparation chamber in heat-exchanging contact with the chamber an air channel (61) which is separated at least vapour-tightly from the chamber, wherein further air displacing means (60) are provided for generating and maintaining a further airflow (L1) in the air channel, wherein the air channe comprises adjacently of the access door opening an air inlet for the further airflow, and wherein steam means are provided therein for generating a steam-air mixture in the preparation chamber, characterized in that the air inlet comprises a first air inlet (62) adjacently of the access door (40), comprising an air gap which extends along at least substantially a whole side of the access door, and a further air inlet (63), in that the access door (40) is double-walled, comprising a first wall (41) and a second wall (42) which extend at least substantially parallel to each other and maintain here a cavity (43) relative to each other, in that the first air inlet (62) is in open communication with the cavity (43) on a first side of said cavity and connects at least substantially airtightly to the cavity in the access door in a closed position of the access door (40), and in that the cavity (43) is in open communication with a surrounding area on an opposite side via said further air inlet (63).

2. Device according to claim 1, characterized in that the first wall and the second wall each comprise an at least partially transparent window.

3. Device according to one or more of the preceding claims, characterized in that the preparation chamber is provided with a steam discharge for evacuating an excess of the steam-air mixture from the preparation chamber, and that the housing comprises a further air channel (66) for carrying a further airflow (L2) in heat-exchanging contact with at least a part of the steam discharge.

4. Device according to claim 3, characterized in that the further air displacing means are also able and configured to generate and maintain the further airflow in the further air channel.

5. Device according to claim 3 or 4, characterized in that the steam discharge comprises a condenser in heat-exchanging contact with the further air channel, that the preparation chamber is provided with a liquid discharge, and that the condenser comprises a condensation discharge which debouches in the liquid discharge of the preparation chamber.

6. Device according to claim 5, characterized in that the liquid discharge comprises a water trap and that the condensation discharge debouches upstream of the water trap in the liquid discharge.

7. Device according to one or more of the preceding claims, characterized in that the further air displacing means comprise a collective fan which is able and configured to generate and maintain separate airflows in a number of air channels outside the preparation chamber during operation.