EP2638330A1

EP2638330A1 - Forced convection oven

Info

Publication number: EP2638330A1
Application number: EP11778650.9A
Authority: EP
Inventors: Murat Kantas; Levent Akdag; Haluk Karatas; Mehmet Marasli; Cemalettin Kalayci; Mehmet Baris Gocer; Mehmet Zihni Gurlek
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2010-11-12
Filing date: 2011-11-04
Publication date: 2013-09-18
Also published as: WO2012062679A1

Abstract

The present invention relates to a cooking device (1) comprising an outer cabinet (2), an oven cavity (3) positioned such that there remains a gap between the outer cabinet (2) and itself, at least one heater (4) providing the air therein to be heated, at least one fan (5) which propels the heated air, a fan covering plate (6) which separates the section wherein the heater (4) and the fan (5) are situated from the oven cavity (3), at least one side wall (11) fastened to the both sides of the fan covering plate (6), a flange (17) situated on each of the both sides of the fan covering plate (6) and at least three passage gaps (10, 110, 210) disposed on each flange (17) so as to be one over the other with each other, and in the oven cavity (3) of which a homogenous heat distribution is provided.

Description

[Title established by the ISA under Rule 37.2] FORCED CONVECTION OVEN

The present invention relates to a cooking device that provides the cooking process to be realized effectively and homogeneously
At least one heater and one fan are provided in ovens wherein the cooking process is performed by means of convection. The casing of the cooking device is divided into two compartments by means of a fan covering plate. The heater and the fan are disposed in the compartment which remains between the rear wall of the casing and the fan covering plate and the other compartment forms an oven cavity wherein foods to be cooked are placed. The air heated by the heater is propelled by the fan and delivered into the oven cavity through the holes arranged on the fan covering plate and the food is provided to be cooked by means of heat transfer between the warm air and the food to be cooked.
In the state of the art, in order to perform the air circulation effectively, blowing holes through which the air propelled by the fan is blown into the oven cavity, and sucking holes through which the air transferred into the oven cavity is sucked back into the volume between the fan covering plate and the casing rear wall are provided on the fan covering plate. However, the warm air propelled by the fan is exposed to turbulence effects and corner losses until being received into the oven cavity since it circulates between the fan covering plate and the rear wall in an uncontrolled manner. As a result of this, the flow rate of the circulating air decreases and therefore, the cooking efficiency is reduced.
In multi level cooking devices wherein the cooking process is performed in more than one tray simultaneously, the side walls comprising horizontal channels thereon are utilized in order to perform a homogeneous cooking. Heated air is received from the volume between the fan covering plate and the casing rear wall to the side walls by means of the fan. This air flows through the channel and is delivered to the oven cavity by means of the holes positioned so as to blow the air to the lower and upper surfaces of the tray. By this method, although it is possible to provide a homogenous cooking by means of the holes extending along the tray at a single level, homogeneity cannot be provided between the levels since each channel is not subjected to the same flow rate and the air between the channels mixes with each other. Generally when the food in one level is cooked, the cooking device is stopped assuming that the same type of food in the other levels is also cooked and all the trays are taken from the cooking device simultaneously. In some cases this results in serving the food before it is fully cooked and hence in consumer dissatisfaction.
In the state of the art United States of America Patent Application No US5816234, the delivery of the air, which is received from the oven cavity by means of the fan on the rear wall, to the side walls from the heater room and from here again to the oven cavity by means of the openings, is described.
In the state of the art International Patent Application No. WO2005066549, taking the heated air from the heater room to the side walls by means of the holes situated on the fan covering plate side edges and blowing this air so that it sweeps the tray in the oven cavity from above and below by means of the holes situated along the horizontal axis on the channel, is described.
The aim of the present invention is the realization of a cooking device which provides a homogenous and effective cooking in all the levels of the oven cavity.
In the cooking device realized in order to attain the aim of the present invention, a fan covering plate that separates the section wherein the heater and the fan are located from the oven cavity, three passage gaps on each of the flanges situated on both sides of the fan covering plate and at least one side wall fastened to the side edge of the fan covering plate are disposed. The area of the middle passage gap is greater than the area of the lower and upper passage gaps.
In an embodiment of the present invention, while the areas of the lower passage gap and the upper passage gap are almost equal, the area of the middle passage gap is smaller than the total area of the lower passage gap and the upper passage gap. In the preferred embodiment of the present invention, the area of the middle passage gap is one and half times the area of the lower passage gap or the upper passage gap.
In another embodiment of the present invention, at least one sucking opening, at least one blowing opening and at least one guidance member are provided on the fan covering plate.
In another embodiment of the present invention, the total area of the passage gaps is one and half times to three and half times, preferably two and half times the total area of the blowing openings.
The air transferred from the blowing openings and the holes to the oven cavity is received back to the volume wherein the fan and the heater are situated preferably through the sucking openings disposed on the fan covering plate along the space occupied by the fan. Thus, a cycle that continues during the cooking process is attained.
In another embodiment of the present invention, the fan covering plate and the side walls are mounted angularly with respect to each other in the cooking device. This angle is between 30 and 60 degrees, preferably 45 degrees. In this embodiment, in order to mount the fan covering plate and the side wall with a suitable angle, the flanges of the fan covering plate and the surface of the side walls facing the fan covering plate are produced with a suitable inclination.
In another embodiment of the present invention, the side wall comprises at least one channel having one inlet port providing the air coming from the passage gaps to enter therein and at least one hole arranged along the horizontal axis thereon providing the air received from the inlet port to be blown to the oven cavity, and at least one guide providing the trays to be disposed in the oven cavity to be positioned. The air passing through the passage gaps is received into the channel by means of the air inlet port and while one part of this air flows in the channel, the other part is delivered to the oven cavity by means of the holes. Since equal amount of air passes through each passage gap by means of the different areas of the passage gaps, equal amount of air enters into the channels.
In another embodiment of the present invention, at least one separator is provided on the side wall, which extends along the gap between the inner surface of the side wall and the outer cabinet and prevents the air passage between the channels. Consequently, the equal amount of air received from the channel inlet ports is prevented from mixing with each other, and thus equal amount of air is provided in the channels during the cooking process.
In another embodiment of the present invention, the side walls are detachably mounted to the fan covering plate. In this embodiment, the guide provides the side wall and the fan covering plate to be fastened together and also itself to be grouped onto the side wall by means of its legs which are inserted both into the side wall and the fan covering plate.
In another embodiment of the present invention, the dimensions and shapes of the holes arranged along the channels on the side walls are equal to each other. Since there is air entrance into the oven cavity also through the blowing openings on the fan covering plate, the holes starts from a place close to the center of the channel and continues until the end of the channel on the side of the door. Thus, the portion of the foods facing the rear wall is prevented from being cooked more than the other portions.
By means of the present invention, the cooking process is homogenously and effectively realized in all the levels of the cooking device. Moreover, by means of the special structure of the side wall and the fan covering plate, leak-proof is provided between the fan covering plate and the side wall and between the channels on the side wall.
A household appliance realized in order to attain the aim of the present invention is illustrated in the attached figures, where:
Figure 1 – is the perspective view of the cooking device of the present invention.
Figure 2 – is the perspective view of the oven cavity.
Figure 3 – is the top view of the side wall and the fan covering plate.
Figure 4 – is the perspective view of the side wall and the fan covering plate.
Figure 5 – is the front perspective view of the side wall.
Figure 6 – is the rear perspective view of the side wall.
Figure 7 – is the front perspective view of the fan covering plate.
Figure 8 – is the rear perspective view of the fan covering plate and the fan.
The elements illustrated in the figures are numbered as follows:

Cooking device
Outer cabinet
Oven cavity
Heater
Fan
Fan covering plate
Sucking opening
Blowing opening
Guidance member
110. 210. Passage gap
Side wall
Channel
Inlet port
Hole
Guide
Separator
Flange

The cooking device (1) comprises

an outer cabinet (2),
an oven cavity (3) positioned such that there remains a gap between the outer cabinet (2) and itself,
at least one heater (4) providing the air therein to be heated,
at least one fan (5) which propels the heated air,
a fan covering plate (6) which separates the section wherein the heater (4) and the fan (5) are located from the oven cavity (3),
a side wall (11) fastened to each of the both sides of the fan covering plate (6),
a flange (17) extending backwards from each of the both sides of the fan covering plate (6) and
at least three passage gaps (10, 110, 210) disposed on each flange (17) so as to be one over the other with each other (Figure 1).

A fan covering plate (6) dividing the inner volume into two is disposed in the area near the rear wall of the preferably rectangular-shaped outer cabinet (2). The fan (5) and the heater (4) are located in the volume between the fan covering plate (6) and the outer cabinet (2). The side walls (11) fastened to the fan covering plate (6) are disposed at both sides of the outer cabinet (2). The volume remaining between the opposite side walls (11) and the fan covering plate (6) forms the oven cavity (3) together with the lower and upper surfaces of the outer cabinet (2) (Figure 2). The volume of the oven cavity (3) is generally greater than the volume wherein the fan (5) and the heater (4) are situated. The air heated by the heater (4) and propelled by the fan (5) is directed to the front surface of the fan covering plate (6) and the flanges (17). At least three passage gaps (10, 110, 210), which provide the air to be directed to the side wall (11), are disposed on each flange (17).
In the cooking device (1) of the present invention, the area of the middle passage gap (10) is greater than the areas of the passage gaps (110, 210) located therebelow and thereabove. Since the center point of the fan (5) and the center point of the fan covering plate (6) almost overlap, the flow rate of the air passing through the middle passage gap (10) located at the same horizontal level with the preferably axial type fan (5) is less than the flow rate of the air passing through the lower and upper passage gaps (110, 210). Accordingly, the areas of the lower and upper passage gaps (110, 210) are selected to be smaller than the middle passage gap (10) in inverse proportion with the flow rate of the air passing through the lower and upper passage gaps (110, 210). Thus, almost same amount of air passes through all the passage gaps (10, 110, 210) and a homogenous heat distribution is provided in the cooking device (1) in the vertical axis.
In an embodiment of the present invention, three passage gaps (10, 110, 210) are provided on each flange (17). In this embodiment, the area of the middle passage gap (10) is greater than the lower and upper passage gaps (110, 210).
In another embodiment of the present invention, while the areas of the lower passage gap (110) and the upper passage gap (210) are almost equal, the area of the middle passage gap (10) is smaller than the total area of the lower passage gap (110) and the upper passage gap (210). In the preferred embodiment of the present invention, the area of the middle passage gap (10) is one and half times the area of the lower passage gap (110) or the upper passage gap (210). These ratios are selected according to the air speed profile on the side edge of the fan covering plate (6), changing as per the speed, size and rotational direction of the fan (5) used.
In another embodiment of the present invention, the fan covering plate (6) comprises at least one sucking opening (7), at least one blowing opening (8) and at least one guidance member (9) which direct the air propelled by the fan (5) (Figure 5). The air propelled by the fan (5) is directed towards the blowing openings (8) and the passage gaps (10, 110, 210) on the fan covering plate (6). For the air to more easily reach the blowing openings (8) in the cut-out form situated on the fan covering plate (6), guidance members (9) extending from the inner surface of the fan covering plate (6) to the outer cabinet (2) are disposed on the fan covering plate (6) (Figure 7, Figure 8). The guidance members (9) are disposed in various geometry and sizes in different sections of the fan covering plate (6) depending on the angle and speed of the air coming from the fan (5). Thus, the amount of the air leaving the blowing openings (8) by impacting the guidance members (9) is increased. Consequently, a homogenous and effective air distribution is attained in the front side of the oven cavity (3). In the meantime, some amount of the air is directed to the passage gaps (10, 110, 210) on the flange (17) and passes from here to the side wall (11).
In another embodiment of the present invention, the total area of the passage gaps (10, 110, 210) is one and half times to three and half times the total area of the blowing openings (8). In the preferred embodiment of the present invention, the total area of the passage gaps (10, 110, 210) is two and half times the total area of the blowing openings (8). Since the air received to the side wall (11) flows along the entire side wall (11) in the horizontal axis, it is subjected to various losses. By means of the selected ratio, equal amounts of air are provided to be blown from the fan covering plate (6) and the side walls (11) and thus the foods in the tray are provided to be cooked more homogeneously.
The air delivered from the fan covering plate (6) and the side walls (11) to the oven cavity (3) is received back to the volume wherein the fan (5) and the heater (4) are situated preferably through the sucking openings (7) disposed on the fan covering plate (6) along the space occupied by the fan (5). Thus, a cycle that continues during the cooking process is attained.
In another embodiment of the present invention, the fan covering plate (6) and the side wall (11) are mounted angularly with respect to each other (Figure 3, Figure 4).
In a variation of this embodiment, the fan covering plate (6) and the side wall (11) are mounted to each other with an angle between 30 and 60 degrees. In the preferred embodiment of the present invention, this angle is 45 degrees. Thus, leak-proof is provided during the air passage from the volume wherein the fan (5) is situated to the side wall (11), and the cooking effectiveness is increased by reducing the corner losses.
In another embodiment of the present invention, the side wall (11) comprises at least one channel (12) having one inlet port (13) providing the air coming from the passage gaps (10, 110, 210) to enter therein and at least one hole (14) arranged along the horizontal axis thereon providing the air taken from the inlet port (13) to be blown to the oven cavity (3), and at least one guide (15) providing the trays (X, Y, Z) to be disposed in the oven cavity (3) to be positioned. The air passing through the passage gaps (10, 110, 210) is received into the channel (12) by means of the air inlet port (13) and while one part of this air flows in the channel (12), the other part is delivered to the oven cavity (3) by means of the holes (14). Since equal amount of air passes through each passage gap (10, 110, 210) by means of different areas of the passage gaps (10, 110, 210), equal amount of air enters into the channels (12). Moreover, since the air that enters the channel (12) is delivered to the oven cavity (3) along the horizontal axis by means of the holes (14), a homogenous air distribution is obtained. Consequently, the foods of the same type in the trays (X, Y, Z) positioned so as to be swept by the air exiting the holes (14) are cooked in an equal period of time since they are exposed to an almost equal amount of heat.
In another embodiment of the present invention, five passage gaps (10, 110, 210) are provided on each flange (17). One middle passage gap (10) and two lower and two upper passage gaps (110, 210) are provided in this embodiment.
In a variation of this embodiment, the side wall (11) comprises at least one separator (16) which extends along the gap between the inner surface thereof and the outer cabinet (2) and prevents the air passage between the channels (12) (Figure 6). Consequently, the equal amount of air received from the inlet ports (13) are prevented from mixing with each other, and thus equal amount of air is provided in the channels (12) during the cooking process.
In another embodiment of the present invention, the side walls (11) are detachably mounted to the fan covering plate (6). Thus, the side walls (11) can be easily taken out of the outer cabinet (2) and cleaned, and can be mounted to their place again afterwards.
In another embodiment of the present invention, the dimensions and shapes of the holes (14) arranged along the channels (12) on the side wall (11) are identical. Thus, the values such as temperature and pressure of the air blown from each hole (14) situated on the channel (12) are provided to be as same as possible. Since there is air entrance into the oven cavity (3) also through the blowing openings (8) on the fan covering plate (6), the holes (14) start from a place close to the center of the channel (12) and continue until the end of the channel (12) on the side of the door (Figure 6). Thus, the portion of the foods facing the fan covering plate (6) is prevented from being cooked more than the other portions.
By means of the present invention, the cooking process is homogenously and effectively realized in all the levels of the cooking device (1). Moreover, by means of the special structure of the side wall (11) and the fan covering plate (6), leak-proof is provided between the fan covering plate (6) and the side wall (11) and between the channels (12) on the side wall (11).
It is to be understood that the present invention is not limited to the embodiments disclosed above and a person skilled in the art can easily introduce different embodiments. These should be considered within the scope of the protection postulated by the claims of the present invention.

Claims

A cooking device (1) comprising

- an outer cabinet (2),

- an oven cavity (3) positioned such that there remains a gap between the outer cabinet (2) and itself,

- at least one heater (4) providing the air therein to be heated,

- at least one fan (5) which propels the heated air,

- a fan covering plate (6) which separates the section wherein the heater (4) and the fan (5) are situated from the oven cavity (3),

- a side wall (11) fastened to each of the both sides of the fan covering plate (6),

- a flange (17) extending backwards from each of the both sides of the fan covering plate (6) and

- at least three passage gaps (10, 110, 210) disposed on each flange (17) so as to be one over the other with each other,

characterized by at least one middle passage gap (10) the area of which is greater than the areas of the passage gaps (110, 210) located therebelow and thereabove.
A cooking device (1) as in Claim 1, characterized by three passage gaps (10, 110, 210) situated on each flange (17).
A cooking device (1) as in Claim 1 or 2, characterized by the lower passage gap (110) and the upper passage gap (210), the areas of which are almost equal.
A cooking device (1) as in Claim 3, characterized by the middle passage gap (10) the area of which is smaller than the total area of the lower passage gap (110) and the upper passage gap (210).
A cooking device (1) as in Claim 3, characterized by the middle passage gap (10) the area of which is one and half times the area of the lower passage gap (110) or the upper passage gap (210).
A cooking device (1) as in any one of the above claims, characterized by the fan covering plate (6) which directs the air propelled by the fan (5) and comprises at least one sucking opening (7), at least one blowing opening (8) and at least one guidance member (9).
A cooking device (1) as in Claim 6, characterized by the passage gaps (10, 110, 210) the total area of which is one and half times to three and half time the total area of the blowing openings (8).
A cooking device (1) as in Claim 7, characterized by the passage gaps (10, 110, 210) the total area of which is two and half times the total area of the blowing openings (8).
A cooking device (1) as in any one of the above claims, characterized by the fan covering plate (6) and the side wall (11) which are mounted angularly with respect to each other.
A cooking device (1) as in Claim 9, characterized by the fan covering plate (6) and the side wall (11) which are mounted to each other with an angle between 30 and 60 degrees.
A cooking device (1) as in Claim 9 or 10, characterized by the fan covering plate (6) and the side wall (11) which are mounted to each other with an angle of 45 degrees.
A cooking device (1) as in any one of the above claims, characterized by the side wall (11) that comprises at least one channel (12) having one inlet port (13) providing the air coming from the passage gaps (10, 110, 210) to enter therein and at least one hole (14) arranged along the horizontal axis thereon providing the air taken from the inlet port (13) to be blown to the oven cavity (3), and at least one guide (15) providing the trays (X, Y, Z) to be disposed in the oven cavity (3) to be positioned.
A cooking device (1) as in Claim 12, characterized by the side wall (11) that comprises at least one separator (16) which extends along the gap between the inner surface of the side wall (11) and the outer cabinet (2) and prevents the air passage between the channels (12).
A cooking device (1) as in any one of the above claims, characterized by the side wall (11) which is detachably mounted to the fan covering plate (6).