Cooking appliance with atomizing device

Abstract

Cooking appliance (1) comprising a heater (5) for heating a cooking chamber (2) by means of a hot exhaust air stream (S) and comprising an atomizing device (21) arranged on the heater (5) for humidifying the cooking chamber (2), wherein the atomizing device (21) is configured to spray water mist (W) into the exhaust air stream (S) of the heater (5), the heater (5) is a forced-air heater comprising a blower (7) and an annular heating element (8) surrounding the blower (7), and the atomizing device (21) is arranged at an exhaust opening (12) of a housing (6) accommodating the heater (5), characterized in that the atomizing device (21) has a common supply channel (14) for pressurized water for several atomizing nozzles (23), the forced-air heater comprises the blower (7) and the annular heating element (8). contained in a pot-like housing (6) and two crossed struts (22) are arranged in the discharge airflow (S),which are connected to the supply channel (14), each of the struts (22) having atomizing nozzles (23) on its side facing away from the direction of flow of the discharge air stream (S).

Description

[0001] The invention relates to a cooking appliance which has a cooking chamber which can be heated by means of a circulating air heater and an atomising device arranged on the circulating air heater for introducing water mist into the cooking chamber.

[0002] DE 103 47 614 A1 discloses a cooking appliance with an interior space that can be closed by a door, comprising a cooking chamber and a blower chamber, separated from the cooking chamber by an air guide member with at least one intake opening and one exhaust opening, for at least one blower device, a heating device and a humidification device, wherein the humidification device has at least one water supply line and at least one outlet, wherein the water supply line comprises a deflection device for water guided therein, which is connected at one end to the wall of the blower chamber opposite the air guide member and at its other end positions the outlet in such a way that a spray jet of the outlet strikes a fan wheel of the blower device directly.

[0003] GB 2 146 222 A describes that in a known method for baking, for example, bread, the dough pieces are exposed to a steam atmosphere, which is created by introducing steam from a boiler into the oven, in order to cause the top of the loaf to glaze, reduce cracking of the top of the loaf, and reduce the elasticity of the loaf. In order to reduce the running costs of the oven, according to GB 2 146 222 A, atomizers are attached to the oven, and liquid water is supplied to the atomizers to create a steam atmosphere in the oven. Preferably, the atomizers are of a type that are fed not only with liquid water, but also with compressed air, which causes the water to atomize.

[0004] DE 10 2004 001 221 A1 discloses a device and a method for closing / opening at least one inlet and / or outlet of a container, in particular of a cooking appliance, with a sealing body which can be displaced between a position keeping the inlet and / or outlet at least partially open and a position closing the inlet and / or outlet at least substantially fluid-tight. It is provided that the sealing body is coupled to a volume of a switching fluid via a force coupling mechanism, so that with the aid of a change in the pressurization of the switching fluid, the sealing body can be displaced between the open and the closed position.

[0005] It is the object of the present invention to provide a simple and reliable way of nebulizing a cooking chamber, by means of which calcification and thermal stress on the circulating air heating system are minimized.

[0006] This object is achieved by means of a cooking appliance according to claim 1. Preferred embodiments can be found in particular in the dependent claims.

[0007] The cooking appliance has a cooking chamber, in particular an oven pipe, that can be heated by a heater. The cooking chamber is typically defined by a muffle and a cooking chamber door. The heater can, for example, be arranged as a circulating air heater on a wall, in particular the rear wall, of the muffle and usually has a fan and a ring heater arranged around the fan. When the circulating air heater is in operation, air is sucked in from the cooking chamber by the fan, heated by the ring heater, and blown back into the cooking chamber. Furthermore, an atomizing device is arranged on the heater for humidifying the cooking chamber. The atomizing device is designed to spray water mist into at least one exhaust air stream of the heater, in particular into an area behind a fan and a heater. As a result, neither the fan nor the heater are sprayed with water, so that no minerals (limescale, etc.) build up on their surfaces.) deposits. Instead, the minerals are dissolved in hot air and cannot bond as firmly to the surfaces of the device. Furthermore, the minerals are comparatively easy to remove from the muffle walls. Another advantage is that thermal stresses are avoided, which can occur when these surfaces cool due to uneven wetting with water and which can potentially lead to cracking. Another advantage is that atomization can be achieved using simple technology and few components.

[0008] The heating system is a convection heater. This is already present in most ovens, allowing humidification of the cooking chamber with simple means and without the need for complex adjustments. The convection heater contains the fan and the ring heater surrounding the fan in a pot-like housing.

[0009] The atomizing device is located at an outlet opening of a housing that houses the heater. This allows for simple and cost-effective installation of the atomizing unit while simultaneously requiring minimal installation depth and ensuring particularly early mixing of the water mist with the exhaust air stream.

[0010] In principle, the type of atomizing nozzle is not limited and can include, for example, single-component pressure nozzles (such as turbulence, flat jet, impact and hollow cone pressure nozzles), dual-component or pneumatic nozzles (such as airbrush nozzles) or mechanical atomizers (such as ultrasonic nebulizers).

[0011] The atomization device has a plurality of atomizing nozzles and a common supply channel (“common rail”) for the plurality, in particular all, of the atomizing nozzles.

[0012] Furthermore, two crossed struts are arranged in the exhaust air flow, which are connected to the supply duct, each of the struts having atomizing nozzles on its side facing away from the flow direction of the exhaust air flow.

[0013] The multiple atomizing nozzles can advantageously be operated together. Alternatively or additionally, the atomizing nozzles or subsets of the atomizing nozzles can be controlled individually. Individual control allows for particularly finely dosed water mist application, and it can also be spatially variable.

[0014] For spatially uniform spraying or injection into an exhaust air flow, in particular of a conventional circulating air heater with a round exhaust opening, the supply channel can advantageously be designed to be annular at least in sections.

[0015] For effective mixing of the water mist with the exhaust air flow over a short distance, the at least one atomizing nozzle can advantageously be aligned such that it sprays perpendicular to a flow direction of the exhaust air flow.

[0016] Alternatively or additionally, the at least one atomizing nozzle can also be aligned so that it sprays parallel to a flow direction of the exhaust air flow.

[0017] For simple and reliable adjustment of the introduction of water mist, it is preferred if the cooking appliance has a control device configured to control the amount of water mist sprayed into the exhaust air stream. The control may, for example, comprise continuous spraying or intermittent spraying ("steam burst"). In the case of intermittent spraying, the control may comprise the duration of a spray burst and the interval between spray bursts. Particularly with continuous spraying, it may be advantageous if the control device can adjust the spray volume by adjusting the water pressure.

[0018] A predetermined relationship between humidity and temperature can advantageously be achieved by adjusting the amount of water mist sprayed into the exhaust air stream depending on the air temperature in the mixing zone. A mixing zone is understood to be the area in which the sprayed water mist and the exhaust air stream still mix significantly. The mixing zone can, in particular, include an area between the atomizing device and a baffle. In this case, it may be preferable to only spray when the temperature in the mixing zone is greater than or equal to 100°C, in particular greater than or equal to 120°C, because this ensures rapid evaporation of the water mist.

[0019] A predetermined relationship between humidity and temperature can also be advantageously achieved by adjusting the amount of water mist sprayed into the exhaust air stream depending on the air temperature in the cooking chamber. In this case, it may be preferable if spraying only occurs when the temperature in the cooking chamber is greater than or equal to 100°C, in particular greater than or equal to 120°C.

[0020] A constant humidity in the cooking chamber can be advantageously achieved if the amount of water mist sprayed into the exhaust air stream can be adjusted depending on the required humidity.

[0021] Advantageously, the atomizing device can be configured to spray water mist into at least one of the heater's multiple exhaust air streams. For this purpose, the heater can have multiple exhaust openings, e.g., exhaust nozzles. Water mist can then be sprayed into all exhaust air streams, particularly for uniform atomization, or water mist can be selectively sprayed into one or more selected exhaust air streams for targeted atomization.

[0022] The cooking appliance can, for example, be designed as a stove or an oven.

[0023] The method is used to humidify a cooking chamber, whereby water mist is sprayed into at least one exhaust air stream of a heater, in particular a recirculation heater.

[0024] The invention is described in more detail schematically in the following figures using an exemplary embodiment. For clarity, identical or equivalent elements may be provided with identical reference numerals. Fig. 1 shows a front view of an open oven; Fig. 2 shows an oblique view of a circulating air heating pot of an oven with an atomizing device; Fig. 3 shows the atomization device from Fig. 2 from the front; and Fig. 4 shows an atomization device according to the invention from the front.

[0025] Fig. 1 shows a front view of an oven 1 with a view into an open cooking chamber (oven) 2. An oven door for closing the cooking chamber 2 is omitted for clarity. The open cooking chamber 2 is defined by a muffle side wall 3 and a muffle rear wall 4. Arranged in the muffle rear wall 4 is a circulating air heater 5 which, in a pot-like housing 6, contains a fan 7 and a ring heater 8 surrounding the fan 7. To illustrate the circulating air heater 5, a baffle that usually covers the front of the circulating air heater 5 is omitted. In circulating air mode, the fan 7 draws air from the then closed cooking chamber 2 and returns the drawn-in air past the hot ring heater 8 back into the cooking chamber 2. This allows the cooking chamber 2 to be heated evenly. The associated exhaust air flow can be at least partially directed by the baffle.The operation of the oven 1 is controlled or regulated by a control device 9, which receives its inputs from a control panel 10. To regulate the cooking chamber temperature, a temperature sensor 11 connected to the control device 9 is arranged in or on the cooking chamber 2. An oven 1 equipped in this way is well known.

[0026] Fig. Figure 2 shows the circulating air heater 5 in greater detail. The fan 7 is located in the pot-like housing 6, and the ring heater 8 with two heating coils is located at the edge of the fan 7. When the fan 7 is in operation, an exhaust air flow S is generated, indicated by the arrow, which blows air through an exhaust opening 12 in the housing 6 into the Fig. 1 shown cooking chamber 2, possibly deflected by the baffle wall.

[0027] To increase the humidity in the cooking chamber 2, an atomizing device 13 is provided at the edge of the exhaust opening 12. The atomizing device 13 has an annular supply channel 14 running around the edge of the exhaust opening 12, which carries pressurized water. The supply channel 14 is supplied with water via a pressurized water supply line 15, wherein a pump 16 connected to the water supply line 15 is provided to generate pressure. The pump 16 can be connected directly to a fresh water supply or to a storage tank. The pump 16 is controlled by the control device 9, e.g., with regard to the water pressure to be generated. For faster and more precise water supply to the supply channel 14, an optional shut-off valve 17 is interposed between the pump 16 and the supply channel 14, the optional opening and closing of which can also be controlled by the control device 9.To dampen pressure fluctuations, a pressure vessel 18 may be present in the pressurized part of the water supply line 15.

[0028] The control device 9 is thus configured to control the amount of water mist sprayed into the exhaust air stream S, as well as a spray profile. The control can, for example, consist of setting a time interval between two opening phases and / or the duration of the opening phases of the atomizing nozzles 19. The control device 9 can be connected to the temperature sensor 11 to control the spraying; the control device 9 can then adjust the atomization based on a cooking chamber temperature. A second input variable can be a measured air humidity, which can be measured, for example, by means of a humidity sensor 20 in the mixing area of ​​the water mist and the exhaust air stream S or in the cooking chamber 2. The control device 9 can then adjust the air humidity to a desired target air humidity by actuating the atomizing device 13.

[0029] For atomization, the atomizing device 13 has atomizing nozzles 19 mounted equidistantly on the inner edge of the supply duct 14, which spray a water mist W into the exhaust air stream S of the recirculating air heater 5. For this purpose, the atomizing nozzles 19 are directed inwards, perpendicular to the flow direction of the exhaust air stream S. A main spray direction of the atomizing nozzles 19 is thus perpendicular to the flow direction of the exhaust air stream S, which here corresponds to the y-direction. When the atomizing device 13 is operated together with the recirculating air heater 5, the water mist W is sprayed into the hot exhaust air stream S behind the fan 7 and the annular heater 8 by means of the atomizing nozzles 19. This increases the humidity in the exhaust air stream S, while the temperature is lowered by absorbed evaporative heat. This moist air stream is blown into the cooking chamber 2 and distributed very evenly.Since the water does not reach the fan 7 or the annular heating element 8, they do not become calcified. In the worst case, a small amount of limescale may build up on the muffle wall or on oven shelves, but it is easily removed. Furthermore, the fan 7 and the annular heating element 8 are not subjected to mechanical stress by local cooling of the surface. Furthermore, the circulating air heating system 5 itself requires little or no modification, providing a simple and cost-effective method for nebulization.

[0030] Fig. 3 shows the atomization device 13 from Fig. 2 from the front. The atomizing nozzles 19 each spray a water mist W essentially perpendicular (directed within the x,z plane) to the exhaust stream S (parallel to the y-axis).

[0031] Fig.4 shows a further atomization device 21, in which two crossed struts 22 are now arranged in the exhaust air stream S, which are connected to the supply duct 14. Each of the struts 22 has atomizing nozzles 23 on its downstream side, which point in the direction of the exhaust air stream S and thus spray essentially in a flow direction of the exhaust air stream S. The sprayed mist is entrained by the exhaust air stream S and distributed in the cooking chamber 2.

[0032] Of course, the present invention is not limited to the illustrated embodiments. Water can, in principle, be sprayed into the exhaust air stream S at any angle. Furthermore, the atomizing nozzles do not need to be supplied via a common supply channel (“common rail”); individually supplied atomizing nozzles can also be used, e.g., as pump-nozzle injection nozzles. The atomizing nozzles can be driven mechanically and / or hydraulically, for example. The atomizing nozzles can also be arranged within the housing of the circulating air heater behind the fan and the annular heater, or even spaced apart from the circulating air heater. List of reference symbols 1 oven 2 cooking chamber 3 Muffle side wall 4 muffle back wall 5 Recirculating air heating, heating 6 housings 7 fans 8 ring heaters 9 Control device 10 Control panel 11 Temperature sensor 12 Exhaust opening of the housing 13 Atomization device 14 supply channel 15 Water supply line 16 Pump 17 Shut-off valve 18 pressure vessels 19 Atomizing nozzle 20 Humidity sensor 21 Atomization device 22 struts 23 Atomizing nozzle S Exhaust air flow W Water mist

Claims

[1] Cooking appliance (1), comprising a heater (5) for heating a cooking chamber (2) by means of a hot exhaust air stream (S) and comprising an atomizing device (21) arranged on the heater (5) for humidifying the cooking chamber (2), wherein the atomizing device (21) is designed to spray water mist (W) into the exhaust air stream (S) of the heater (5), the heater (5) is a circulating air heater which contains a fan (7) and a ring heater (8) surrounding the fan (7), and the atomizing device (21) is arranged on an exhaust opening (12) of a housing (6) accommodating the heater (5), characterized byin that the atomizing device (21) has a common supply channel (14) for pressurized water for a plurality of atomizing nozzles (23), the circulating air heating contains the fan (7) and the annular heating element (8) in a pot-like housing (6), and two crossed struts (22) are arranged in the exhaust air flow (S), which are connected to the supply channel (14), each of the struts (22) having atomizing nozzles (23) on its side facing away from the flow direction of the exhaust air flow (S). [2] Cooking appliance (1) according to claim 1, characterized by that the at least one atomizing nozzle (23) is aligned such that it sprays parallel to the flow direction of the exhaust air flow (S). [3] Cooking appliance (1) according to one of the preceding claims, characterized by that it has a control device (9) which is designed to control an amount of water mist (W) sprayed into the exhaust air stream (S). [4] Cooking appliance (1) according to claim 3, characterized by that the quantity of water mist (W) sprayed into the exhaust air stream (S) is adjustable depending on an air temperature in a mixing range of water mist (W) and exhaust air stream (S). [5] Cooking appliance (1) according to claim 3 or 4, characterized by that the quantity of water mist (W) sprayed into the exhaust air stream (S) can be adjusted depending on the air humidity. [6] Cooking appliance (1) according to one of the preceding claims, characterized by that the atomizing device (21) is designed to spray water mist (W) into at least one exhaust air stream of a plurality of exhaust air streams of the heater (5). [7] Cooking appliance (1) according to one of the preceding claims, characterized by that the atomizing device (21) is designed to spray water mist (W) in pulses into the exhaust air flow (S) of the heater (5). [8] Cooking appliance (1) according to one of the preceding claims, characterized by that the atomizing device (21) is designed to spray water mist (W) into the exhaust air flow (S) of the heater (5) when a temperature in a mixing area and / or in the cooking chamber (2) is greater than or equal to 100°C.

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