EP1010384B1 - Cooking apparatus and method for heat treatment of a cooking product with steam - Google Patents

Description

The invention relates to a cooking appliance for heat treatment of a food with a cooking space for holding a food and one with the cooking space via a steam supply connectable steam generator. The invention relates Furthermore, a method for heat treatment of a food in such a Cooking appliance.

Cooking appliances for heat treatment (e.g. thawing, reheating, cooking, roasting, Baking) of a cooking product introduced into a cooking chamber with a steam / air mixture (Fluid) as heat transfer are known in different versions. They have in common that the steam required for this purpose by a steam generator is generated, which essentially integrated into the cooking chamber (internal Steam generator) or outside of the cooking chamber and arranged with this example. can be connected via a steam supply line (external steam generator). With "Steam supply" is the entire channel of steam from the steam generator referred to the cooking space.

There are, for example, cooking appliances with a cooking vessel and a lid-like Cover enclosing a cooking space. Either in the cooking vessel or in the cover is a steam generator.

Other cooking appliances have a muffle which can be closed by a door, in which the cooking chamber is located. This group includes steam ovens, which are special equipment, especially for the heat treatment of Serve with steam (steam ovens). Furthermore belong to this group Combination cooking appliances, in particular baking and roasting ovens, in which besides the conventional types of heating, such as top and / or bottom heat and / or heating air circulation, also a steam operation for treating the food with a Steam / air mixture can be selected.

EP 0 673 615 A1 shows a steam oven with one of a muffle and a door enclosed cooking space and an internal steam generator. This includes a heatable plate on the muffle bottom and one above the plate ending, connected to a water reservoir, through a valve lockable water supply pipe. Water coming to the hot plate evaporates, and the steam produced rises in the cooking chamber due to its Buoy up from bottom to top of the introduced food over on.

In the Kombinationsgargerät disclosed in EP 0 277 337 B1 is in the Muffle bottom of the cooking chamber a pot-like, by means of electrical heating elements heated evaporation vessel inserted, which is connected to a Water supply line is connected. In steam operation is in the Evaporative tank filled water through the heating elements for Evaporation brought. The generated steam rises from the evaporation tank in the oven.

In DE 36 39 872 C2 is a cooking appliance with one of a pot-shaped cooking vessel and a lid-like cover surrounded cooking space described. In the Cover is an external steam generator housed, the one Evaporation tank and a steam heater for heating and Evaporating the filled into the evaporation vessel water. Of the In this way, excess steam generated by a steam supply in pressed the cooking chamber.

DE 195 37 751 A1 and EP 0 666 046 A1 show combination cooking appliances in each case an external steam generator, which in the DE 195 37 751 A1 illustrated embodiments outside the muffle and in the EP 0 666 046 A1 shown inside the muffle in an installation room behind the cooking chamber is arranged. The steam generator is with the cooking space over a Steam supply connectable and has a water-fillable Evaporation tank with a steam radiator to evaporate in the Evaporative container filled water. The steam in the Steam generator in excess generated steam escapes due to Pressure gradient between steam generator and cooking chamber via the steam supply line in the cooking space.

In the known cooking appliances, especially those with external Steam generator, is disadvantageous that for the supply of the cooking chamber with steam an overpressure must be built in the steam generator, by a Excess amount of steam is generated. This results in a considerable energy and water consumption and a high amount of condensate.

The invention is based on the task, a cooking appliance and a method in which, while maintaining a good cooking result the Steam supply in the cooking chamber is improved and the disadvantages of the state of the Technology can be avoided.

To solve this problem is in a cooking appliance of the type mentioned proposed that there is a flow unit for promoting in the Steam generator has generated steam in the cooking chamber.

The flow unit may be used in cooking appliances with external steam generator (e.g. Steam ovens, combination cookers, cooking appliances with cooking vessels and one Cover-like cover, etc.) are used. It creates a flow of the steam generator in the direction of the cooking chamber, resulting in an improved, more uniform supply of steam results in the cooking chamber. Due to the Steam delivery by means of the flow unit is in the inventive Cooking appliance excessive steam production to build one for the Steam supply of the cooking chamber required overpressure not required. As a result, the energy consumption for steam generation, the Water consumption and condensate reduced. The by the Flow unit generated flow also causes in the steam generator a Lowering the pressure, resulting in a boiling point reduction of the vaporized Water and thus leads to further energy savings.

To further improve the steam supply and the accessibility for example To facilitate the case of required maintenance is the flow unit in a preferred embodiment of the invention in the oven, preferably in Mouth region of the steam supply line, arranged. Alternatively, she could For example, in or on the steam supply line (for example in a bypass), in Steam generator or be arranged at another location in the oven.

In an advantageous embodiment of the invention, the cooking appliance has a Cooking chamber associated convection fan with one of a drive motor driven convection fan for circulating steam and / or air in the cooking space. In this way, by the flow unit in the Garraum promoted steam with the existing air in the oven or the existing vapor / air mixture well mixed and the generated vapor / air mixture evenly distributed in the cooking space. Depending on your needs can Flow unit and convection fan individually or together in operation.

Basically, any device can be used as a flow unit, the can generate a flow, e.g. a pump, a reciprocating compressor, a blower or another compressor type. In an advantageous embodiment of the invention the flow unit as an intake fan with one of a drive motor driven Ansauglüfterrad formed. In this case, the intake fan is arranged so that the steam generator on its suction side and the cooking chamber on its pressure side lie. In this way, commercially available, in oven area already for other purposes (e.g., hot air blower) are advantageously used components for the Steam extraction can be used.

The intake fan may preferably be a radial fan, which sucks the vapor along its axis of rotation and it in the radial direction blows away. Such a blower type has a high efficiency and is suitable especially good to build up a sufficient pressure gradient. Dependent on from the location of the suction fan, the design of the steam supply etc., other types of fans can be used advantageously.

Preferably, the suction fan and the convection fan have one common drive motor on. The fact that both with a drive motor Fan wheels are driven, the design effort of the cooking appliance reduced. Furthermore, it is advantageous if the Ansauglüfterrad and the Rotate convection fan around a common axis of rotation. Through this Measure becomes a particularly uniform distribution of steam in the oven achieved since the sucked by the Ansauglüfterrad steam directly with the fluid swirled by the convection fan wheel is mixed.

The invention also provides a process for the heat treatment of a Gargutes in a cooking appliance of the type mentioned. In the process is the steam generated in the steam generator by means of a flow of a Flow unit is generated, promoted in the cooking chamber.

The fact that the steam conveyed by the flow targeted and not as a result pressed a built in the steam generator pressure in the cooking chamber is, essentially only as much steam is generated, as it is for the Steam supply of the cooking chamber is required. This reduces the energy and water consumption as well as the accumulation of condensate.

Fig. 1

ein erstes Ausführungsbeispiel des erfindungsgemäßen Gargerätes in einer Schnittdarstellung in Seitenansicht und

Fig. 2

ein zweites Ausführungsbeispiel des erfindungsgemäßen Gargerätes in einer Schnittdarstellung in Seitenansicht.

Two exemplary embodiments of the cooking appliance according to the invention and the method according to the invention will be described below with reference to schematic representations. Show it:

Fig. 1

a first embodiment of the cooking appliance according to the invention in a sectional view in side view and

Fig. 2

A second embodiment of the cooking appliance according to the invention in a sectional view in side view.

Fig. 1 shows an example of a cooking appliance 1 according to the invention Combination cooking appliance (baking and roasting oven with steam function). It points in one Housing 2 a muffle 3, which is surrounded by an insulating material 4 and at her Front side by a door 5 with handle 6 is closed. Muffle 3 and door 5 are surrounded a cooking chamber 7 for receiving a food. Through a partition wall 9, the is arranged such that between its edge and the wall of the cooking chamber. 7 at least one passage opening 10 remains, the cooking chamber 7 in a front Gargutaufnahmebereich 7a and a rear steam supply portion 7b divided. The cooking appliance 1 also has a Wrasenaustrittsöffnung 8, the cooking chamber. 7 connects with the atmosphere and thus always ensures an open system. she is in the present embodiment in the lower region of the cooking chamber. 7 formed between the muffle front and the door 5. Not shown is a optional condensate drain to remove condensed Water from the cooking chamber 7. In the upper part of the front of the cooking appliance 1 is an operating element 11, with which an operator has the desired operating function of the cooking appliance 1 can be arranged.

Furthermore, a steam generator 12 can be seen, the below the muffle. 3 is arranged. This has an evaporation container 13 for receiving to evaporating water and a steam heater 14 for heating in the Evaporation container 13 located water. The not shown Water supply to the steam generator 12 may for example by means of a Water supply line or one of the operator fillable movable Wassereinfüllbehälters done.

Of course, the steam generator 12 could also be at a different position (for example above, laterally, behind or within the muffle 3). Further In the context of the invention, other types of steam generators may also be advantageous be used, for example, a steam generator, an atomizer and having a radiator for vaporizing the atomized water.

The steam generator 12 is connected via a steam supply line 15 with the cooking chamber. 7 it is not absolutely necessary that these - as shown - is guided by the insulating material 4 of the muffle 3. However, this arrangement has in the Compared to a running in the space between the housing 2 and insulation Steam supply 15 the advantage that the steam on the transport substantially does not cool and condensation is counteracted. Also one within the cooking chamber 7 laid steam supply 15 would be possible. The Steam supply line 15 opens at the rear wall 16 of the muffle 3 in the Steam supply area 7b of the cooking chamber 7, but could of course also at another point in the cooking chamber 7 open.

The cooking appliance 1 further comprises a flow unit 17 for conveying in the Steam generator 12 generated steam in the cooking chamber 7. This is in the Cooking chamber 7 arranged in the mouth region 18 of the steam supply line 15 and as An intake fan 19 is formed, the one of an electric drive motor 20 via an axle 21 driven Ansauglüfterrad 22 has. The fan wheel back is facing away from the rear wall 16 of the muffle 3. When the intake fan 19 acts it is a radial fan, which in operation, the steam along its axis of rotation sucks (suction side 23a) and blows away in the radial direction (pressure side 23b). The Steam supply line 15 opens at the suction side 23a of the intake fan 19, so that via the steam supply line 15 and the steam generator 12 at the intake fan suction side 23a lies. In order to achieve a good conveying effect, it can be advantageous be when the garraumseitige end portion 24 of the steam supply line 15 and the Axle 21 of the intake fan 19 include an angle. In a the Embodiment corresponding arrangement of steam supply line 15 and Injection fans 19 have in practice angles between 15 ° and 75 °, preferably an angle of about 45 ° proven. Whether an angle or which angle depends on the particular arrangement and training of the Steam generator 12, the steam supply line 15, the flow unit 17 u.a. from.

In the area of the rear wall 16 of the muffle 3 is behind the partition 9 also a Convection fan 25 with a Konvektionslüfterrad 26 for circulating steam and / or air in the cooking chamber 7 is arranged. With the convection fan 25 it can advantageously also be a radial fan. convection fan 25 and intake fan 19 have in the illustrated embodiment a common drive motor 20. This is the Ansauglüfterrad 22 in Direction of the partition wall 9 upstream Konvektionslüfterrad 26 on the same Axis 21 as attached to the Ansauglüfterrad 22, wherein the Lüfterradrückseiten facing each other. Alternatively, the Ansauglüfterrad on a the Convection fan-axis surrounding, rotatable sleeve be attached, so that Although both fans with the same drive motor, but independent are operable from each other. The Ansauglüfterrad 22 can be smaller in diameter be as or substantially the same size as the Konvektionslüfterrad 26 be. Instead of two fan wheels, a special fan could also be used, which combines the functions of suction fan and convection fan.

The convection fan 26 and / or the Ansauglüfterrad 22 is of a surrounded annular fan heater 27 (shown greatly simplified). Convection fan 25 and fan heater 27 form in a conventional manner a hot air blower for heating the cooking chamber 7. The heating of However, cooking space 7 does not have to take place or not only via the hot air blower, but could alternatively or additionally by conventional heating elements for upper and / or Lower heat can be achieved. The provision of a Ansauglüfterrad 22nd and / or the Konvektionslüfterrad 26 surrounding fan heater 27 has but the advantage that the steam / air mixture. before it's over the least a passage opening 10 in the Gargutaufnahmebereich 7a passes, if necessary can be heated by the fan heater 27. This allows a Heat treatment of the food with a smaller fluid Steam saturation level.

In the housing 2, a control device 28 is accommodated over Control lines 29 with the components to be controlled of the cooking appliance. 1 (Drive motor 20, fan heater 27, steam heater 14, etc.) is connected. About the control element 11 of the controller 28 to be controlled Heat treatment process specified.

In the steam supply line 15 is a steam valve 30 or another shut-off element arranged, via the control device 28 for controlling the steam supply in the cooking chamber 7 is controlled. Alternatively, a shut-off element could e.g. by doing Steam generator be provided. If no steam supply into the cooking chamber. 7 should be done, the steam valve 30 is substantially closed, so that even at running intake fan 19 is conveyed substantially no steam. By doing However, steam generator 12 can always be a certain way in this way Amount of steam are kept available, so that after opening the Steam valve 30 steam can be conveyed immediately if it is the respective Heat treatment process required. By the steam valve 30 is thus a particularly fast adjustment of the steam supply to the adjusted Cooking chamber conditions achieved.

For operating the cooking appliance 1, the operator puts on the operating element 11 desired for the cooking product located in the Gargutaufnahmebereich 7a Heat treatment process, which is controlled by the controller 28. If a heat treatment is to take place with steam, the activated Control device 28, the steam radiator 14, in the Evaporation 13 of the steam generator 12 heated water filled and evaporates, and the drive motor 20 of the intake fan 19. Das rotating suction fan 22 causes a flow in the steam supply line 15, by the steam generated in the steam generator 12 into the steam supply area 7 b is conveyed, and that he sucks the steam through the steam supply line 15 from the steam generator 12 and blows it in the radial direction away in the cooking chamber. 7 By the current generated by the convection fan 26 also current current is blown away from the Ansauglüferrad 22 with steam from the Convection fan 26 from the Gargutaufnahmebereich 7a at the Suction side 31a sucked air or sucked vapor / air mixture evenly mixed. Via the pressure side 31b of the convection fan 25 flows the fluid through the at least one passage opening 10 in the Gargutaufnahmebereich 7a and transfers the heat to the food. By the Wrasenaustrittsöffnung 8 escapes the fluid to the outside.

When performing special heat treatment operations, the Control device 28 also selected radiator (fan heater 27, Radiator for top or bottom heat etc - if available) in combination with or drive completely without steam. For example, if the food is with a Steam / air mixture treated a relatively low degree of vapor saturation is to be, the controller 28 may e.g. the fan heater 27 activate to heat the fluid.

In some heat treatment processes with a vapor / air mixture can it may be advantageous to supply the steam at regular intervals or as needed to interrupt or reduce. For this purpose, the control device 28 closes the Steam valve 30 substantially wholly or partially, wherein the steam heater 14th is controlled so that a certain amount of steam in the steam generator 12th remains. In this way, steam is available quickly, if that Steam valve 30 for a renewed or increased steam supply again or further is opened.

In the cooking appliance 1 shown in FIG. 2, the steam supply into the cooking chamber 7 controlled by the controller 28 via the steam production by the Control device 28, the steam heater 14 and / or the flow unit 17th (here: the suction fan 19) controls. If no steam is to be produced, is about turning off or reducing the heating power of the steam heater 14, the temperature of the water in the evaporation vessel 13 is lowered, so that even when the intake fan 19 is running substantially no steam is produced. Alternatively or additionally, the steam production can also via the operation of the Ansauglüfters 19 are controlled. For this purpose, the control device 28 holds this evaporating water by means of the steam heater 14 substantially on a constant temperature below the boiling temperature at normal pressure (i.e. of the prevailing in the steam generator 12 with the intake fan 19 off Pressure). Only one through the current intake fan 19 in the steam generator 12th caused pressure reduction and thus boiling point reduction leads to Evaporation of the water. In a further variant could additionally an in the steam supply line 15 arranged shut-off be provided.

Incidentally, structure and function of the second embodiment correspond essentially those of the first embodiment.

The invention was exemplified in the embodiments with reference to a Baking and roasting oven with steam function described, however, is not on one limited such cooking appliance.

LIST OF REFERENCE NUMBERS

1

Cooking appliance

2

casing

3

muffle

4

insulating material

5

door

6

Handle

7

oven

7a

Gargutaufnahmebereich

7b

Steam supply area

8th

Wrasenaustrittsöffnung

9

partition wall

10

passage opening

11

operating element

12

steam generator

13

Evaporation container

14

steam radiators

15

steam supply

16

rear wall

17

flow unit

18

mouth area

19

suction fan

20

drive motor

21

axis

22

Ansauglüfterrad

23a

Suction side of 19

23b

Print page of 19

24

end

25

convection fan

26

Konvektionslüfterrad

27

fan heater

28

control device

29

control lines

30

steam valve

31a

Suction side of 25

31b

Print page of 25

Claims (14)

1. Cooking appliance for heat treatment of stock to be cooked, with a cooking chamber (7) for receiving stock to be cooked and a steam generator (12) connectible with the cooking chamber (7) by way of a steam feed duct (15), characterised in that the cooking appliance (1) comprises a flow unit (17) for conveying steam, which is produced in the steam generator (12), into the cooking chamber (7).
2. Cooking appliance according to claim 1, characterised in that the flow unit (17) is arranged in the cooking chamber (7), preferably in the mouth region (18) of the steam feed duct (15).
3. Cooking appliance according to claim 1 or 2, characterised in that it comprises a convection fan (25), which is associated with the cooking chamber (7), with a convection fanwheel (26), which is driven by a drive motor (20), for the circulation of steam and/or air in the cooking chamber (7).
4. Cooking appliance according to one of the preceding claims, characterised in that the flow unit (17) is constructed as a suction fan (19) with a suction fanwheel (22) driven by a drive motor (20), wherein the suction fan (19) is so arranged that the steam generator (12) lies at its suction side (23a) and the cooking chamber (7) at its pressure side (23b).
5. Cooking appliance according to claim 4, characterised in that the suction fan (19) is constructed as a radial fan which inducts the steam along its axis of rotation and blows it away in radial direction.
6. Cooking appliance according to claim 4 or 5, characterised in that the suction fan (19) and the convection fan (25) have a common drive motor (20).
7. Cooking appliance according to claim 6, characterised in that the suction fanwheel (22) and the convection fanwheel (26) rotate about a common axis of rotation.
8. Cooking appliance according to one of the preceding claims, characterised in that it comprises a control device (28).
9. Cooking appliance according to claim 8, characterised in that for control of the steam feed into the cooking chamber (7) a steam heating body (14) of the steam generator (12) and/or the flow unit (17) is or are controllable by means of the control device (28).
10. Cooking appliance according to claim 8 or 9, characterised in that for control of the steam feed into the cooking chamber (7) it comprises a blocking element (30) which is controllable by the control device (28) and which is preferably arranged in the steam feed duct (15).
11. Method of heat treatment of stock, which is to be cooked, in a cooking appliance with a cooking chamber (7) for receiving stock to be cooked and a steam generator (12) connectible with the cooking chamber (7) by way of a steam feed duct (15), characterised in that the steam produced in the steam generator (12) is conveyed into the cooking chamber (7) by means of a flow which is produced by a flow unit (17).
12. Method according to claim 11, characterised in that the steam is sucked out of the steam generator (12) by means of a flow unit (17), which is arranged in the cooking chamber (17), via the steam feed duct (15) and blown into the cooking chamber (7).
13. Method according to claim 11 or 12, characterised in that the steam feed into the cooking chamber (7) is controlled by means of a control device (28) in that this controls a steam heating body (14) of the steam generator (12) and/or the flow unit (17).
14. Method according to one of claims 11 to 13, characterised in that the steam feed into the cooking chamber (17) is controlled by means of a control device (28) in that this opens or closes as required a blocking element (30) preferably arranged in the steam feed duct (15).

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