EP3089590A1

EP3089590A1 - Cooking oven with improved hot air circulation

Info

Publication number: EP3089590A1
Application number: EP13815788.8A
Authority: EP
Inventors: Metin Gur
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2013-12-30
Filing date: 2013-12-30
Publication date: 2016-11-09
Also published as: WO2015101399A1

Abstract

The present invention relates to a cooking oven (1) comprising a chamber (2) for cooking food therein, a cell (3) including a fan (4) for generating air flow, an intake port (5) for drawing air into the cell (3) by the suction effect of the fan (4), a heater for heating the air taken into the cell (3), and a control unit for controlling the heater and the fan (4), one or more than one channel (7) including an inlet port (8) which is fluidly connected to the discharge end of the fan (4).

Description

COOKING OVEN WITH IMPROVED HOT AIR CIRCULATION

The present invention relates to a cooking oven. The present invention particularly relates to a cooking oven which has means for cooking food by convective heat transfer. The present invention more particularly relates to a cooking oven which has a jet impingement heat transfer facility.
The jet impingement technology enables cooking, baking or drying food faster than the conventional cooking technologies. In a cooking oven utilizing the jet impingement technology, hot air is jetted onto the food through a plurality of orifices by using a fan and a heater. Thereby, a relatively large amount of heat can be transferred to the food within a relatively short time. Hence, the cooking time drastically decreases. Due to the shortened cooking time, the jet impingement technology is widespreadly used by the food industry, particularly in the mass production of food. However, the jet impingement technology can also be used in domestic type cooking ovens.
A problem with the jet impingement method is that the juice of the food rapidly escapes. Therefore, the outcome of the cooking process may easily degrade. Another problem with the jet impingement technology is that there is a risk that the food may not be uniformly cooked. A fast heat transfer can easily compromise uniform cooking. In particular, in case of a non-uniform impingement of the hot air jets onto the food, as some parts of the food which receive relatively more jets of hot air become well done, other parts which receive relatively less jets of hot air may still require additional time for the completion of the cooking. Therefore, the outcome of a cooking process may easily degrade.
CA 2 512 912 A1 discloses a high speed oven which utilizes the jet impingement method. This high speed oven includes a cooking chamber, a fan and a heater which are arranged to suck the air out of the chamber and to discharge the air, after heating the same into the chamber through a jet plate. This high speed oven has a turntable for improving uniform cooking of the food.
A drawback of the above-mentioned high speed oven is that turntable includes several mechanical parts which require additional manufacturing steps. This incurs extra costs. Moreover, the structure and the control of the oven become relatively sophisticated.
An objective of the present invention is to provide a cooking oven which overcomes the aforementioned drawbacks of the prior art and which has an improved functionality and usability.
This objective has been achieved by the cooking oven according to the present invention as defined in claim 1. Further achievements have been attained by the subject-matters respectively defined in the dependent claims.
The cooking oven of the present invention comprises one or more than one channel which includes an inlet port and a plurality of outlet openings. The inlet port is fluidly connected to the discharge end of the fan in a cell, which generates hot pressurized air. The plurality of outlet openings are arranged to jet the hot pressurized air vertically downwards into the chamber. The cooking oven of the present invention further comprises air intake means for fluidly connecting an intake port of the cell to an ambient air outside the chamber and/or to an air inside the chamber. The air intake means is controlled so as to draw ambient air outside the chamber and/or air inside the chamber into the cell by the suction effect of a fan.
By virtue of the air intake means the relative humidity in the cooking chamber can be prevented from decreasing rapidly during the hot air circulation. Thereby, a rapid drying of the food can prevented and the food can be cooked while retaining most of its juice.
In an embodiment, the cooking oven has only one channel which forms the entire ceiling of the cooking oven. The outlet openings are arranged uniformly into the ceiling of the cooking chamber.
In another embodiment, the cooking oven has a plurality of channels which together form the entire ceiling of the cooking oven. The channels are separated from each other, for example by partition walls. The hot air is equally shared between the channels and uniformly impinged onto the food. In a version of this embodiment, the channels extend spirally outward from a center of the ceiling to a periphery thereof. The outlet openings of each channel are sequentially arranged along an entire span of the spiral-shaped channel. In another version of this embodiment, the fan has spiral-shaped blades and is centered at a vertex of the plurality of channels.
In an alternative version of this embodiment, the channels are not stationary but rotatably arranged. The rotatable channels are suspended from the ceiling or embedded into a recess of the ceiling of the cooking oven. The rotatable channel extends radially outward from a center of the ceiling to a periphery. Thereby, hot air jets can be uniformly swept over the entire food. In version of this embodiment, the rotatable channels are made from a light-weight metal material so as to rotate under the influence of the hot air being jetted without any auxiliary means such as motor. Thereby, the energy efficiency of the cooking oven has been increased.
In another embodiment, inlet ports or the outlet openings of the channels can be selectively be opened/closed to set a desired portion of the cooking chamber for the cooking.
In another embodiment, the cooking oven has a roasting mode, a grilling mode, a steam cooking mode, and a normal cooking mode. In this embodiment, the wattage of the heater and a speed of the fan is adjusted in accordance with the selected mode. Thereby, the need for installing any additional heating resistance on a lower interior portion or an upper interior portion of the cooking chamber has been both obviated. Also a flow path of the hot air jets has been cleared from obstacles like electrical resistances which have become superfluous.
In another embodiment, an additional heater has been installed underside the cooking chamber. In this embodiment, the cooking oven has only two heaters, namely the heater in the cell, and the additional heater under the cooking chamber.
By the present invention a cooking oven has been provided which generates a uniform jet of hot air towards the food in the cooking chamber. Due to the improved flow characteristic of the hot air, the food can be uniformly cooked. By the present invention, a rapid drying of the food has been prevented and the food can be cooked while retaining most of its juice. By the present invention the usability of the cooking oven has been increased to enable grilling, roasting or normal cooking by using not more than two heaters. By the present invention, the need for electrical heating resistances including a grill resistance and an upper resistance has been obviated. Thereby, the overall structure has been simplified without compromising the functionality of the cooking oven.
Additional advantages of the cooking oven according to the present invention will become apparent with the detailed description of the embodiments with reference to the accompanying drawings in which:
Figure 1 - is a schematic perspective partial view of a cooking oven according to an embodiment of the present invention;
Figure 2 - is another schematic perspective partial view of a cooking oven according to an alternative embodiment of the present invention.
The reference signs appearing on the drawings relate to the following technical features.

Cooking oven
Chamber
Cell
Fan
Intake port
Tray
Channel
Inlet port
Outlet opening
Ceiling
Blade
Motor
Wall

The cooking oven (1) comprises a chamber (2) for cooking food therein, a ceiling (10) above the chamber (2), a cell (3) including a fan (4) for generating air flow above the ceiling (10), an intake port (5) for drawing air into the cell (3) by the suction effect of the fan (4), a heater (not shown) for heating the air taken into the cell (3) and a control unit (not shown) for controlling the heater and the fan (4) (Figs. 1 and 2)
The cooking oven (1) according to the present invention comprises one or more than one channel (7) including an inlet port (8) which is fluidly connected to the discharge end of the radially blowing fan (4) which blows the hot air radially in the cell (3) and a plurality of circular-shaped outlet openings (9) arranged on the channel (7) longitudinally for jetting the hot air vertically downwards into the chamber (2). The cooking oven (1) according to the present invention further comprises air intake means (not shown) for fluidly connecting the intake port (5) of the cell (3) to an ambient air outside the chamber (2) and/or to an air inside the chamber (2). The control unit is configured to control the air intake means to draw ambient air outside the chamber (2) and/or air inside the chamber (2) into the cell (3) by the suction effect of the fan (4) (Figs. 1 and 2).
In an embodiment, the cooking oven (1) comprises only one channel (7). This single channel (7) includes an inlet port (8) which is fluidly connected to the fan (4) in the cell (3) and a plurality of outlet openings (9) for jetting the hot air vertically downwards into the chamber (2). The outlet openings (9) are uniformly arranged on an upper portion of cooking chamber (2). In this embodiment, a bottom of the channel (7) configures the ceiling (10) of the cooking chamber (2). The outlet openings (9) are uniformly formed into the ceiling (10).
In another embodiment the cooking oven (1) comprises a plurality of channels (7) (Figs. 1 and 2). In this embodiment, each channel (7) includes an inlet port (8) which is fluidly connected to the radially blowing end of the fan (4) in the cell (3) and a plurality of outlet openings (9) for jetting the hot air vertically downwards into the chamber (2). In this embodiment, the channels (7) are separated from each other by partition walls (13). Thereby, the hot air discharged from the cell (3) is equally shared by the channels (7). Hence, the hot air can be uniformly impinged onto the food.
In another embodiment, the air intake means includes a valve mechanism (not shown) which fluidly connects the intake port (5) of the cell (3) to an ambient air outside the chamber (2) and/or to an air inside the chamber (2). In this embodiment, the control unit controls the valve mechanism so as to mix the ambient air and the hot air at a desired ratio. In a version of this embodiment, said ratio is determined based on the humidity inside the chamber (2) which is detected by a humidity sensor (not shown).
In another embodiment, the plurality of channels (7) are arranged above the ceiling (10) of the chamber (2) (Fig. 1). Each channel (7) is configured by a portion of the celling (8), two opposing walls (13) and a portion of an upper cover (not shown). In this embodiment, each channel (7) extends spirally outward from a center of the ceiling (10) to the periphery of the ceiling (10). The walls (13) have a spiral shape. In this embodiment, the plurality of outlet openings (9) of each channel (7) are sequentially formed into the ceiling (10) along an entire span of the channel (7). Thereby, the hot air discharged from the cell (3) is equally shared between the channels (7) and uniformly conveyed to the outlet openings (9). In a version of this embodiment, the fan (4) has a plurality of spiral shaped blades (11). The fan (4) is arranged above the ceiling (10) and at a vertex of the plurality of channels (7) (Fig. 1). Thereby, the hot air is effectively forced into the channels (7). The hot air jetted from the plurality of outlet openings (9) forms a curtain of hot air which uniformly impinges onto the food.
In an alternative embodiment, the cooking oven (1) has a plurality of channels (7) which are rotatably arranged under the ceiling (10) of the chamber (2) so as to rotate around an axis which is perpendicular to the ceiling (10) (Fig. 2). In this embodiment, each channel (7) extends radially outward from a center of the ceiling (10) to the periphery of the ceiling (10). Thereby the hot air can be swept over the food. The hot air inside the cooking chamber (2) is effectively stirred as the plurality of channels (7) rotates. In a version of this embodiment, the cooking oven (1) has four cylindrical shaped channels (7) which are arranged to constitute a cross-shaped structure.
In another version of this embodiment, the channels (7) are made from a light-weight metal material so as to rotate under the influence of the hot air being jetted out through the outlet openings (9).
In an alternative version of this embodiment, the cooking oven (1) further comprises a motor (not shown) which is arranged to rotate the channels (7). In a version of this embodiment, a motor (12) of the fan (4) can be utilized in combination with a reduction gear (not shown) to rotate the channels. In another version of this embodiment the light-weight material is aluminum. Due to the heat capacity of the metal channels (7), the cooking process is continued for a while by the heat radiated off the channel (7) after the jetting of hot air has been terminated. This is particularly advantageous in case of baking pastry or the like. Thus, the metal channels (7) function temporarily as a substitute for a conventional heating resistance disposed on a ceiling (10) of the chamber (2).
In another embodiment, the cell (3) has a truncated cone shape. The cell (3) is configured by a central portion of the ceiling (10) and an upper cover (not shown).
In another embodiment, the outlet openings (9) are circular-shaped (Figs. 1 and 2). The size of a circular-shaped outlet opening (9) is chosen so as to enable jetting of the hot air.
In another embodiment, the circular-shaped outlet openings (9) are arranged sequentially in radial directions and said outlet openings (9) having decreasing diameters from the center to the periphery of the ceiling (10). The size of a circular-shaped outlet opening (9) is chosen so as to enable jetting of the hot air.
In another embodiment, the cooking oven (1) comprises a sensor (not shown) for detecting a rise of the food and for outputting a signal indicative of said detected rise. In this embodiment, the control unit is further configured to reduce a rotation speed of the fan (4) in accordance with the detection signal.
In another embodiment, the control unit has a plurality of user selectable modes including a roasting mode, a grilling mode, and a normal mode. In this embodiment the motor (12) of the fan (4) is a variable speed motor (12). In this embodiment, the control unit is configured to set the wattage of the heater and the speed of the fan (4) in accordance with the selected mode. Thereby, the need for installing any additional heating resistance on a lower interior portion and an upper interior portion of the cooking chamber have been both obviated, and thereby, a flow path of the hot air jets have been cleared from obstacles like electrical heating resistances.
In another embodiment, the cooking oven (1) comprises a steam generator (not shown) having a steam outlet. The stem outlet opens into the cell (3) at an upstream side of the heater. Thereby, the steam can be slightly heated prior to jetting onto the food. In this embodiment, the control unit further includes, in addition to the above-mentioned modes, a steam cooking mode to perform steam cooking.
In another embodiment, the cooking oven (1) comprises means (not shown) for separately opening/closing the inlet ports (8) or the outlet openings (9) of the channels (7). Thereby, a desired portion of the cooking chamber (1) i.e., a specific part thereof can be selectively subjected to jets of hot air.
In another embodiment, the cooking oven (1) comprises a cooling system (not shown) for ventilating its electrical parts or the like. In this embodiment, an exhaust port (not shown) of the cooling system is fluidly connected to an intake port (5) of the cell (3) at an upstream side of the heater. Thereby, preheated air supplied from the cooling system can be conveyed into the cell (3). This increases an energy efficiency of the cooking oven (1). In a version of this embodiment, a blower and a blower motor of the cooling system has been used instead of the fan (4) and the motor (12) of the cell (3). Thereby, the overall structure of the cooking oven (2) has been further simplified.
In another embodiment, the heater is arranged on an upstream side of the fan (4). Thereby, the stream of hot air outflowing from the fan (4) into the channels (7) is not disturbed by the presence of the heater.
In another embodiment, a shaft of the motor (12) is provided, in addition to the fan (4), with a ventilator (not shown) for cooling the exterior parts of the cooking oven (1).
In another embodiment, an additional heater (not shown) has been installed underside the cooking chamber (2). In this embodiment, the cooking oven (1) has only two heaters, namely the heater in the cell (3) and the additional heater under the cooking chamber (2).
The cooking oven (1) according of the present invention can be operated in various different ways. In the subsequent description two operation schemes will be explained in detail. The schemes can be used in combination, i.e., simultaneously or sequentially.
In a first operation scheme, said additional heater is energized. Thereby, a lower tray (6) is heated from below. The rotational speed of the fan (4) is reduced. The air intake means is controlled such that the cell (3) draws hot air from the cooking chamber (2) via the intake port. Thereby, a hot air curtain is impinged through the plurality of outlet openings (9) onto the food inside the tray (6) while the latter is also heated from below.
In another operation scheme, the rotational speed of the fan (4) and the wattage of the heater in the cell (3) are respectively adjusted to desired levels through a user input. The air intake means is controlled such that the cell (3) draws ambient air from the outside of the cooking chamber (2). The hot air is impinged through the plurality of outlet openings (9) onto the food in the tray (6).
In each of the first scheme and the second scheme, the additional heater arranged under the cooking chamber (2) and the heater arranged in the cell (3) can be used in combination, i.e., simultaneously or sequentially. In each of the first and second schemes, the air intake means can be controlled to draw ambient air from an outside of the chamber (2) and hot air from an inside of chamber (2) at any desired ratio.
By the present invention a cooking oven (1) has been provided which generates a uniform jet of hot air towards the food in the cooking chamber (2). Due to the improved flow characteristic of the hot air, the food can be uniformly cooked. By the present invention a rapid drying of the food has been prevented. Hence, the food can be cooked while retaining most of its juice. By the present invention the usability of the cooking oven (1) has been increased to enable grilling, roasting or normal cooking by using not more than two heaters. By the present invention, the need for electrical heating resistances including a grill resistance and an upper resistance has been obviated.

Claims

A cooking oven (1) comprising a chamber (2) for cooking food therein, a ceiling (10) above the chamber (2), a cell (3) including a fan (4) for generating air flow above the ceiling (10), an intake port (5) for drawing air into the cell (3) by the suction effect of the fan (4), a heater for heating the air taken into the cell (3) and a control unit for controlling the heater and the fan (4), characterized in that one or more than one channel (7) including an inlet port (8) which is fluidly connected to the discharge end of the radially blowing fan (4) and a plurality of outlet openings (9) arranged on the channel (7) for jetting the hot air vertically downwards into the chamber (2).
The cooking oven (1) according to claim 1, characterized in that a plurality of channels (7) are arranged above the ceiling (10) of the chamber (2), wherein each channel (7) extends spirally outward from a center of the ceiling (10) to a periphery of the ceiling (10), and wherein the plurality of outlet openings (9) of each channel (7) are sequentially formed into the ceiling (10) along an entire span of the channel (7).
The cooking oven (1) according to claim 2, characterized in that the circular-shaped outlet openings (9) being arranged sequentially in radial directions and said outlet openings (9) having decreasing diameters from the center to the periphery of the ceiling (10).
The cooking oven (1) according to claim 2, characterized in that the fan (4) has a plurality of spiral shaped blades (11), wherein the fan (4) is arranged above the ceiling (10) and at a vertex of the plurality of channels (7).
The cooking oven (1) according to claim 1, characterized in that a plurality of channels (7) are rotatably arranged under the ceiling (10) of the chamber so as to rotate around an axis which is perpendicular to the ceiling (10), wherein each channel (7) extends radially outward from a center of the ceiling (10) to a periphery of the ceiling (10).
The cooking oven (1) according to claim 5, characterized in that four cylindrical shaped channels (7) which are arranged to constitute a cross-shaped structure.
The cooking oven (1) according to claim 5 or 6, characterized in that the channels (7) are made from a light-weight metal material so as to rotate under the influence of the hot air being jetted through the outlet openings (9).
The cooking oven (1) according to any one of the claims 5 to 7, characterized in that a motor (12) which is arranged to rotate the channels (7).
The cooking oven (1) according to any one of the claims 1 to 8, characterized in that a sensor for detecting a rise of the food and for outputting a signal indicative of said detected rise, wherein the control unit is configured to reduce a rotation speed of the fan (4) in accordance with the detection signal.
The cooking oven (1) according to any one of the claims 1 to 9, characterized in that the control unit has a plurality of user selectable modes including a roasting mode, a grilling mode, and a normal mode wherein the control unit is configured to set a wattage of the heater and a speed of the fan (4) in accordance with the selected mode.
The cooking oven (1) according to any one of the claims 1 to 10, characterized in that a steam generator having a steam outlet, wherein the stem outlet opens into the cell (3) at an upstream side of the heater.
The cooking oven (1) according to any one of the claims 1 to 11, characterized in that means for separately opening/closing the inlet ports (8) or the outlet openings (9) of the channels (7).
The cooking oven (1) according to any one of the claims 1 to 12, characterized in that a cooling system for ventilating electrical parts, wherein an exhaust port of the cooling system is fluidly connected to an intake port (5) of the cell (3) at an upstream side of the heater.
The cooking oven (1) according to any one of claims 1 to 4, characterized in that the heater is arranged on an upstream side of the fan (4).
The cooking oven (1) according to any one of claims 1 to 14, characterized in that air intake means for fluidly connecting the intake port (5) of the cell (3) to an ambient air outside the chamber (2) and/or to an air inside the chamber (2), wherein the control unit is configured to control the air intake means to draw ambient air outside the chamber (2) and/or air inside the chamber (2) into the cell (3) by the suction effect of the fan (4).