WO2012117378A1

WO2012117378A1 - Cooking oven, particularly for household use

Info

Publication number: WO2012117378A1
Application number: PCT/IB2012/050991
Authority: WO
Inventors: Fabio Gambardella; Silvio Corrias; Carlo COLUMBARIA
Original assignee: Indesit Company S.P.A.
Priority date: 2011-03-03
Filing date: 2012-03-02
Publication date: 2012-09-07
Also published as: EP2681492A1; EP2681492B1; ITTO20110191A1

Abstract

The present invention relates to a cooking oven (1), particularly for household use, of the type that comprises: - a cabinet (2) with a muffle (3) housed therein, the latter being adapted to be closed by a door (4), - first (5A) and second (5B) panes, which are adapted to create at least one first gap (6A) in said door (4), - a cooling system (10) located above said muffle (3) and comprising a fan (11) and a delivery duct (12), which are adapted to blow a forced-air flow into said first gap (6 A); - exhaust means (20) associated with an aperture (3A) in the muffle (3), for drawing air from within said muffle (3) and exhausting it out of the oven (1). The peculiarity of the invention is that said exhaust means (20) comprise: - a first channel (21) formed on an upper portion of said delivery duct (12) and adapted to draw at least one portion of the air processed by said fan (11); - a second channel (22) for the passage of air coming from said aperture (3A), said second channel (22) comprising a first section (22A) substantially facing the fan (11) and a second section (22B) having such orientation as to lie over the first channel (21).

Description

"COOKING OVEN, PARTICULARLY FOR HOUSEHOLD USE"

DESCRIPTION

The present invention relates to a cooking oven, particularly for household use, as defined in the preamble of claim 1.

In household cooking ovens, doors are usually employed which comprise two or three parallel panes, particularly of glass, to allow visual monitoring of the food being cooked in the oven.

Prior art cooking ovens have the drawback that they have to prevent the outer pane from reaching excessive temperatures, and become dangerous in case of accidental contact therewith, particularly in case of pyrolytic ovens.

In an attempt to obviate this drawback, it is known in the art to form a door comprising at least one first and one second panes, which are adapted to create a gap therebetween, to reduce the transfer of heat from the oven to the outer pane.

Nevertheless, in spite of said gap, the outer pane still usually reaches an excessive temperature.

As a result, it is known in the art to blow air into said gap, by either natural or forced convection, to improve the cooling effect on the panes of the door of a cooking oven, particularly of the outer pane, as viewed relative to a muffle of the oven.

For instance, a cooking oven is, particularly for household use, is known in the art, of the type that comprises:

- a muffle which is adapted to be closed by a door,

- at least one first and one second panes, which are adapted to create a gap in said door,

- a cooling system located above said muffle and comprising a fan and a delivery duct, which are adapted to blow air into said gap.

According to the above described solution, this cooking oven comprises exhaust means associated with an aperture in the muffle, for drawing air from within said muffle and exhausting it out of the cooking oven.

Particularly, these exhaust means comprise a first channel formed on an upper portion of said delivery duct for the passage of air coming from said aperture, said first channel being associated with a second channel formed on said upper portion of the delivery duct and adapted to draw at least one portion of the air processed by said fan.

Nevertheless, this prior art solution suffers from certain drawbacks, as the area where the first and second channels join together is too close to the oven door; therefore, the air processed by the fan has too little space available for adequately facilitating the outflow of cooking fumes contained in the muffle.

This inevitably causes the exhaust means to be poorly effective in exhausting the air drawn from within the muffle out of the cooking oven.

A further drawback of the above solution is that, since the cooking fumes cannot adequately mix with the air flow processed by the fan, large amounts of condensation build up on the outer front wall of the oven.

Thus, the main object of the present invention is to obviate the above drawbacks and provide a cooking oven, particularly for household use, which is so designed as to effectively exhaust the air drawn from within said muffle out of the cooking oven.

Another object of the present invention is to provide a cooking oven, particularly for household use, comprising exhaust means which are so designed as to ensure optimal performance in exhaustion of the cooking fumes drawn from within the oven muffle, thereby avoiding the build-up of condensation and hence dripping on the outer front wall of the oven.

Another object of the present invention is to provide a cooking oven, particularly for household use, comprising a cooling system which is so designed as to allow the closing door of the muffle to ensure high efficiency in thermal insulation and cooling of the outer surface.

A further object of the present invention is to provide a cooking oven, particularly for household use, comprising a cooling system which is so designed as to allow the door to ensure adequate visibility of the oven muffle and the food contained therein.

In view of fulfilling such objects, the present invention provides a cooking oven, particularly for household use, incorporating the features of the annexed claims, which are intended as an integral part of the present description.

Further objects, features and advantages of the present invention will become apparent from the following detailed description and from the annexed drawings, which are only given by way of non-limiting example, in which:

- Fig. 1 is a lateral sectional view of an embodiment of a cooking oven, particularly for household use, according to the present invention;

- Fig. 2 shows a detail of the lateral section of Fig. 1, according to an advantageous embodiment of the present invention;

- Figs. 3 and 4 are an exploded perspective view and a perspective view respectively of a detail of the cooking oven, particularly for household use, according to the present invention.

Referring to the accompanying figures, numeral 1 generally designates a cooking oven, particularly for household use, the type that comprises:

- a cabinet 2 with a muffle 3 housed therein, the latter being adapted to be closed by a door 4,

- first 5A and second 5B panes, which are adapted to create at least one first gap 6A in said door 4,

- a cooling system, generally designated by numeral 10, located above said muffle 3 and comprising a fan 11 and a delivery duct 12, which are adapted to blow a forced-air flow into said first gap 6A.

Particularly, said fan 11 is a tangential fan, and is driven by a motor 13, advantageously of the type that can be controlled at variable speed by the electronic control system (not shown) of the cooking oven 1.

Alternatively, the fan 11 may be a centrifugal or axial fan.

Furthermore, the delivery duct 12 has such a shape as to provide optimal air conveyance into the first gap 6A of the door 4; particularly, such delivery duct 12 is substantially flat and flared and comprises at least one slot 12A for blowing a forced-air flow into said first gap 6 A; Figs. 3 and 4 show a plurality of slots 12A.

As particularly shown in Fig. 1, the door 4 of the cooking oven 1 may comprise a third pane 5C, which is adapted to create a second gap 6B with said second pane 5B.

Preferably, the third pane 5C is associated with the door 4 in such a manner as to keep said second gap 6B free of forced-air; nevertheless, the third pane 5C may be also associated with the door 4 in such a manner as to allow air from the cooling system 10 to flow through the second gap 6B.

In a preferred embodiment, if the cooking oven 1 comprises a plurality of gaps 6A, 6B, the first gap 6A with the forced air flowing therethrough is the inner one, i.e. the one closer to the muffle 3, and the third pane 5C is the outer plane, also having an aesthetic purpose.

Preferably, the door 4 comprises three panes 5A, 5B, 5C at the most, as the cooling system 10 affords highly effective thermal insulation of the muffle 3 and ensures an adequate temperature of the outer pane 5B, 5C, i.e. the one farther from the muffle 3; as a result, the cooling system 10 of the present invention allows the door 4 to be formed of not more than three panes 5 A, 5B, 5C.

As is known in the art, the walls of said muffle 3 are covered with a heat insulating material, and define a cooking compartment, which generally hold heating means (not shown), adapted to raise the temperature in said muffle 3 to a desired food cooking temperature and, in case of a pyrolytic oven, even to a temperature that can activate the cleaning feature to clean the walls of the muffle 3 by pyrolysis.

Furthermore, a space 7 extends between the cabinet 2 and the muffle 3 all around the walls of the muffle 3, to improve thermal insulation between the interior of the muffle 3 and the outer surface of the cabinet 2, said space 7 at least partially accommodating said insulating material, such as glass wool or foam glass.

It shall be noted that the air to be blown into the first gap 6A may be drawn by the cooling system 10 either from the space 7 and/ or from the exterior of the cabinet 2, e.g. through a plurality of slots 2A formed on said cabinet 2.

The sealing effect between the door 4 and muffle 3 is ensured by a gasket 8, generally made of rubber or fiberglass, which is placed either on the edge of the muffle 3 or on the door 4; Fig. 1 only shows the upper and lower portions of the gasket 8.

The cooking oven 1 also comprises exhaust means (generally designated by numeral 20 in the figures), which are associated with an aperture 3A in the muffle 3, for drawing air from within the muffle 3 and exhausting it out of the oven 1.

According to the present invention, these exhaust means 20 comprise:

- a first channel 21 formed on an upper portion of said delivery duct 12 and adapted to draw at least one portion of the air processed by said fan 11;

- a second channel 22 for the passage of air coming from said aperture 3 A, said second channel 22 comprising a first section 22 A substantially facing the fan 11 and a second section 22B having such orientation as to lie over the first channel 21.

Advantageously, said first channel 21 has a rectangular sectional shape with a height and a width of about 10 mm and about 70 mm respectively.

The position of the channel 22, particularly its second section 22B, is especially visible in Figs. 1 and 2, whereas Figs. 3 and 4 show the extension of the first section 22A.

Preferably, said at least one portion of air drawn from the first channel 21 is from 10% to 30%, more preferably from 10% to 20%, particularly about 13% of the airflow handled by the fan 11. This will facilitate the outflow of the cooking fumes contained in the muffle 3 without the use of a dedicated fan.

As particularly shown in Fig. 4, said second channel 22 substantially has a U- shape and comprises a third curvilinear section 22 which acts as a connection between said first 22A and second 22B sections.

Preferably, said second channel 22 is formed on a cover 23 which is adapted to be associated with said upper portion of the delivery duct 12.

Furthermore, particularly Figure 2 shows that said cover 23 is so designed as to include a portion 23A that slopes down towards the first channel 21, said portion 23A being particularly located at said second section 22B of the second channel 22. This arrangement allows the air flow in the second channel 22, particularly said second section 22B, to be conveyed towards the first channel 21; furthermore, it allows the air drawn from within said muffle 3 to be easily pulled by the air that flows in the first channel 21, for advantageously improved discharge of the air drawn from within the muffle 3 and contained in the second channel 22.

According to the present invention, these exhaust means 20 also comprise a plate 30 (as particularly shown in Figs. 1, 2 and 3), which is adapted to be joined to the cover 23 to form the base of the second channel 22; particularly, said plate 30 is fixed under the cover 23 at said second U-shaped channel 22 by known fastener means, such as a plurality of screws 31 (as clearly shown in Figs. 2 and 3), which fit into special housings 23B formed on the cover 23.

Alternatively, the plate 30 may be fixed to the cover 23 by means of rivets or mechanical interlocking arrangements.

In a preferred embodiment, said plate 30 comprises an orifice 32 (as shown in Fig. 3) to allow the air drawn from within the muffle 3 to flow into the second channel 22, particularly said orifice 32 being located at the first section 22A of the second channel 22.

Furthermore, said plate 30 comprises at least one notch 33 to allow the air drawn from within the muffle 3 to flow from the second channel 22 to the first channel 21.

Preferably, said at least one notch 33 has an hopper front shape and is located at the second section 22B of the second channel 22, and allows the air drawn from within the muffle 3 to be pulled through, by the air flow blown by the fan 11 and flowing into the first channel 21, into a third channel 24 formed on an upper portion of said delivery duct 12 and located downstream from the intersection between the first 21 and the second 22 channels. For optimized mixing of the cooking fumes in the air flow that pulls them through, the third channel 24 is at least 250 mm long. In the example of the figures, the length of the third channel 24 is about 300 mm.

As particularly shown in the annexed Figs. 2 and 3, said at least one notch 33 comprises a plurality of notches 33.

Once the plate 30 is attached to it, the cover 23 is welded, e.g. by vibration welding, to the delivery duct 12, to seal the channels 21, 22 and 24, for the plate 30 to be stably locked in its proper position of use.

The exhaust means 20 of the present invention may further comprise an actuator member (referenced 28 in Figs. 1 and 2), such as a gate valve, to discriminate, particularly during a cooking cycle, the time in which the cooking fumes are exhausted out of the cooking oven 1 by forced convection, from the time in which the cooking fumes are exhausted out of the cooking oven 1 by natural convection, or the time in which the muffle 3 is kept substantially tight.

The actuator member 28 is advantageously controlled to prevent or minimize the outflow of cooking fumes from the muffle 3 as the latter is being heated, to reduce the power consumption of the cooking oven 1, or during special cooking operations, such as steam cooking.

Preferably, said actuator member 28 is located substantially at the entrance of the first channel 21.

Furthermore, said actuator member 28 is associated to drive means (not shown), which allow it to assume:

- a first operating state PI (as shown by a solid line in Fig. 2), in which it completely closes the first channel 21 and prevents the air blown by the fan 11 to flow into said first channel 21. Substantially, in said first operating state PI, the cooking fumes may be exhausted out of the cooking oven 1 only by natural convention and, as a result, a very little flow of fumes comes out of the muffle 3;

- a second operating state P2 (as shown by a first broken line in Fig. 2), in which it partially closes the first channel 21 and allows only a portion of the maximum air flow that can be blown by the fan 11 to flow into said first channel 21. As a result, in said second operating state P2, the air drawn from within the muffle 3 and contained in the second channel 22 is only partially pulled through by the air flow blown by the fan 11, and only a reduced flow of cooking fumes is exhausted out of the cooking oven 1;

- a third operating state P3 (as shown by a second broken line in Fig. 2), in which it keeps the first channel 21 completely open and allows the whole air flow blown by the fan 11 to flow into said first channel 21. As a result, in said third operating state P3, the air drawn from within the muffle 3 and contained in the second channel 22 is wholly pulled through by the air flow blown by the fan 11, and the cooking fumes are entirely exhausted out of the cooking oven 1.

It shall be noted that said first PI, second P2 and third P3 operating states of the actuator member 28 as shown in Fig. 2 are such that the position of the actuator member 28 is offset along the first channel 21. In fact, the actuator member 28 preferably has a substantially vertical movement; thus, in said second P2 and third P3 operating states the actuator member 28 is located above the position as shown in Fig. 2 as a first operating state PI.

Alternatively, said actuator member 28 may be located in the third channel 24, i.e. downstream from the intersection between the first 21 and second 22 channels.

The exhaust means 20 of the present invention allow the first 21 and second 22 channels to be joined together substantially proximate to the fan 11; as a result, the air processed by said fan 11 has a wide space available for adequate mixing of the cooking fumes contained in the muffle 3 into the blown air flow that pulls through said cooking fumes out of the cooking oven 1. This will provide exhaust means 20 having an optimized effectiveness in the discharge of the fumes contained in said muffle 3.

Also, as the second channel 22 is formed with a second section 22B that lies over the first channel 21, improved mixing of the cooking fumes drawn from within said muffle 3 with the air processed by the fan 11 is obtained; this advantageously helps to improve the performances of the exhaust means 20 in exhausting said cooking fumes drawn from the muffle 3 out of the oven 1.

Moreover, by providing the plate 30 with at least one notch 33, the air drawn from within the muffle 3 is pulled through by the flow of air blown by the fan 11 in an improved manner.

Furthermore, the exhaust means 20 of the present invention allow the air flow drawn from within said muffle 3 to be kept separate from the flow of air blown into said first gap 6A by the cooling system 10. With the arrangement of keeping the two air flows separate from each other, the door 2 can be designed in such a manner as to ensure adequate visibility of the muffle 3 and the food contained therein, particularly because such design prevents said first gap 6A from becoming fouled and hence from requiring difficult cleaning operations.

Also, the cooling system 10 allows the closing door 4 of the muffle 3 to ensure efficient heat insulation and cooling of the outer surface of said door 4.

The exhaust means 20 are designed in such a manner that the air drawn from within said muffle 3 can be released above an upper edge 4A of the door 4, preferably in a space 40 created between the upper edge 4 A of the door 4 and a lower area 42 of a front panel 41.

There may be a short distance between the lower area 42 of the front panel 41 and the upper edge 4A of the door 4, indicatively ranging from about 2 mm and about 6 mm (and particularly nominally 4 mm or 4.5 mm), to create a nearly seamless surface between the front panel 41 and the door 4, thus leading to advantages in terms of exterior appearance and ease of cleaning of the cooking oven 1.

The, the air in said third channel 24 flows through at least one outlet 25 (as particularly shown in Figs. 2 and 4) and is released into said space 40.

Optimal mixing of cooking fumes into the air flow blown by the fan 11 prevents condensation build-up both on the front panel 41 and on the upper edge 4A of the door 4.

Thus, the cover 23 is adapted to be joined to said upper portion of the delivery duct 12 to enclose said first 21, second 22 and third 24 channels.

Figs. 1 2 and 3 further show that the exhaust means 20 of the present invention also comprise:

- a diverter element 26, particularly having a wedge shape, which is located in said third channel 24 to divert the air flow towards said at least one outlet 25. The diverter element 26 is preferably fitted in by laying it on the delivery duct 12 and securing the cover 23 to said upper portion of the delivery duct 12, the cover 23 being for instance secured by vibration or ultrasonic welding. Thus, the diverter element 26 is permanently trapped in position in its operating seat. Alternatively, the diverter element 26 may be formed of one piece with the delivery duct 12 or the cover 23;

- a tubular element 27 associated with the aperture 3A of the muffle 3 and connected through a gasket (not shown) to a slit 14 (as shown in Fig. 3) of the delivery duct 12 to allow the cooking fumes drawn from within the muffle 12 to reach said second channel 22.

In the embodiment of Fig. 2, the actuator member 2 can determine whether the cooking fumes have to be exhausted from the muffle 3 by natural convection only or with the help of forced convection.

Alternatively, the actuator member 28 may be designed in such a manner as to allow discrimination of the time in which the muffle 3 is kept substantially tight and the time in which the muffle 3 is in fluid communication with the exterior.

This may be achieved in various manners (not shown), including the following:

- the actuator member may be a butterfly valve (possibly having an adjustable opening degree) and be interposed between the tubular element 27 and the second channel 22;

- the actuator member may be inserted in the first channel 22A and may comprise a shutter having the same section as the first channel 22A and a drive mechanism for driving the shutter about a vertical axis, such that the shutter may move (possibly assuming intermediate positions) between a rest position parallel to the flow through the first channel 22A and a closed position orthogonal to the flow through the first channel 22A;

- the actuator member may be conceived in the form of a movable plate, adjacent to the plate 30 and capable of moving parallel thereto to obstruct or clear, as a gate and as needed, the one or more notches 33.

According to the present invention, the upper portion of the delivery duct 12 also comprises a plurality of coupling means 30 for fixing functional elements of the cooking oven 1 to said delivery duct 12. These functional elements are schematically shown in Fig. 4 and may include one or more of the following elements: an electronic card 51, an interface card 52, a door lock device 53 for locking the door 4 and so on.

Preferably, said coupling means 50 are formed by the same molding operation that forms the delivery duct 12, which is made of plastic.

If the cooking oven 1 comprises a microwave generator for at least one microwave-based or microwave-assisted cooking cycle, the door 4 has at least one protective shield therein to prevent microwaves from propagating therethrough, and the cooking oven 1 comprises a safety switch (not shown), which is designed to automatically turn off the microwave generator as the door 4 is opened. The safety switch is advantageously fixed to the cooking oven 1 by being joined to the delivery duct 12 through the coupling means 50.

It will be appreciated that, by providing the delivery duct 12 with coupling means 50 (such as ridges or seats) formed of one piece with the delivery duct 12, the assembly of the cooking oven 1 is greatly simplified, due to its reduced number of components which also involves lower costs. Furthermore, the functional parts are positioned in a more accurate manner, and may be more reliably and safely secured as compared to the prior art.

Concerning the cooling system 10, it is so designed as to generate a downward directed forced-air flow in said first gap 6A; forced air flows through said at least one slot 12A, and then is directed from the upper edge 4A to a lower edge 4B of the door 4.

Since the air flow for cooling the door 4 is separate from the hot flow of cooking fumes, it can adequately cool the entire door 4, including the upper edge 4A, which is where the user is more exposed to accidental contact, as it is close to the front panel 41 with the interface devices (not shown) of the cooking oven 1.

Preferably, an air conveyor element 4A is associated with said upper edge 4A, for conveying the air flow from the cooling system 10 into the first gap 6A and/ or the second gap 6B.

Said conveyor element 9A has a profile of such a shape as to change the direction of the air flow from the cooling system 10 by about 90°. The conveyor element 9A may be associated with the door 4 at the inlet section of the first gap 6A, or it may be associated with any other component of the cooking oven 1 at the outlet section of the delivery duct 12.

Furthermore, the lower edge 4B comprises deflector means 9B associated with said first 5A and second 5B panes, said deflector means 9B being bent in a direction opposite to the muffle 3; the provision of the deflector means 9B allows the air flow from said first gap 6 A and/ or said second gap 6B to be directed towards an external portion of the oven 1, particularly a portion external to said door 4. Advantageously, the flow is diverted in a manner such that it has at least one horizontal motion component.

Such deflector means 9B comprise a pair of deflectors, each possibly consisting of a particular element applied to the structure of the door 4 or obtained by appropriately shaping a structural element of the door 4.

As an alternative, the deflector means 9B may be provided as a single element having both the purpose of securing the first pane 5A, diverting the flow from the first gap 6A, and also, advantageously, collecting any condensation built up the first pane 5A.

Particularly, Figs. 3 and 4 show that the cooling system 10 comprises a cover 60 that is coupled to the underside of the delivery duct 12, said cover 60 having an opening 61 for the passage of the tubular element 27 associated with the aperture 3 A of the muffle 3.

Preferably, said cover 60 is made of sheet metal and is secured to the sides of the cooking oven 1; furthermore an insulating material (not shown) is interposed between said cover 50 and the muffle 3, to prevent any excessive heating of the air to be blown into said first gap 6A, due to the heat of said muffle 3.

The above description clearly shows the advantages of a cooking oven, particularly for household use, according to the present invention.

Particularly, the exhaust means 20 of the present invention allow the first 21 and second 22 channels to be joined together substantially proximate to the fan 11; as a result, the air processed by said fan 11 has a wide space available for adequate mixing of the cooking fumes contained into the air flow that pulls them through out of the cooking oven 1. This will provide exhaust means 20 having an optimized effectiveness in the discharge of the fumes contained in said muffle 3, which also do not form condensation on the outer front wall of the cooking oven 1.

The discharge of the air drawn from within the muffle 3 is further facilitated in that it is pulled through by the air flow that is blown by the fan 11, i.e. at least one portion of air from said fan 11.

Furthermore, the possibility of keeping the flow of air drawn from within said muffle 3 separate from the flow of air blown into said first gap 6A allows the door 4 to be designed in such a manner as to allow adequate visibility of the muffle 3 and the food contained therein, and to prevent said first gap 6 from being fouled thereby. This will avoid difficult cleaning operations.

Another advantage of the cooking oven 1 of the present invention is the provision of a plurality of coupling means 50 on the upper portion of the delivery duct 12; these coupling means 50 provide optimal fixation of functional elements of the cooking oven 1 to said delivery duct 12.

A further advantage is that said cooling system 10 can generate a downward- directed air flow in said first gap 6A, i.e. a flow directed from the upper edge 4A to a lower edge 4B of the door 4; this embodiment advantageously ensures adequate cooling of the upper edge 4 A of the door, which is the most dangerous for the user, as it is the one where an accidental contact is most likely to occur.

Thus, the particular embodiment of the cooking oven 1 of the present invention allows the door 4 to exhibit high efficiency in heat insulation and cooling of the outer surface.

Furthermore, the particular embodiment of the cooking oven 1 of the invention has the additional advantage of using a single fan 11 to both draw air from the muffle 3 and exhaust it above the upper edge 4A of the door 4 and to blow a forced-air flow into the first gap 6A.

Many variants may be envisaged for the cooking oven as illustratively disclosed herein, without departure from the novel concepts of the invention, and the disclosed details may be implemented in different manners, or replaced by technically equivalent parts.

Therefore, it will be appreciated that the present invention is not limited to the cooking oven, particularly for household use, as described above, but is susceptible to various modifications, improvements, replacements of equivalent elements and parts, without departure from the scope of the invention, as better defined in the following claims.

Claims

1. A cooking oven (1), in particular for household use, of the type comprising:

- a cabinet (2) internally housing a muffle (3) adapted to be closed by a door (4), - a first (5A) and a second (5B) panes adapted to create at least a first interspace

(6A) in said door (4),

- a cooling system (10) positioned above said muffle (3) and comprising a fan (11) and a delivery duct (12) adapted to blow air into said first interspace (6A),

- exhaust means (20) associated with an aperture (3A) in the muffle (3) for drawing air from within said muffle (3) and exhausting it outside the oven (1), characterised in that

said exhaust means (20) comprise:

- a first channel (21) obtained on an upper portion of said delivery duct (12) and adapted to draw at least one portion of the air processed by said fan (11);

- a second channel (22) for the passage of the air coming from said aperture (3A), said second channel (22) comprising a first section (22A) substantially facing the fan (11) and a second section (22B) so arranged as to overlap the first channel (21).

2. A cooking oven (1) according to claim 1, characterised in that said second channel (22) is substantially U-shaped and comprises a third curvilinear section (22C) that acts as a link between said first (22A) and second (22B) sections.

3. A cooking oven (1) according to one or more of the preceding claims, characterised in that said second channel (22) is obtained on a cover (23) adapted to be associated with, preferably welded to, said upper portion of the delivery duct (12).

4. A cooking oven (1) according to one or more of claims 1 and 2, characterised in that said cover (23) is so designed as to include a portion (23A) that slopes down towards the first channel (21), in particular said portion (23A) being provided in the region of said second section (22B) of the second channel (22).

5. A cooking oven (1) according to one or more of the preceding claims, characterised in that said exhaust means (20) comprise a plate (30) adapted to be associated with the cover (23) so as to constitute a base for the second channel (22).

6. A cooking oven (1) according to claim 5, characterised in that said plate (30) comprises at least one notch (33) allowing the air drawn from within the muffle (3) to pass from the second channel (22) to the first channel (21), in particular said at least one notch (33) having a hopper front shape and being positioned in the region of second section (22B) of the second channel (22).

7. A cooking oven (1) according to one or more of the preceding claims, characterised in that said exhaust means (20) comprise an actuator (28) for discriminating, in particular during a cooking cycle, between the periods in which the cooking fumes are evacuated outside the cooking oven (1) by forced convection, those in which the cooking fumes are evacuated outside the cooking oven (1) by natural convection, and those in which the muffle (3) is kept substantially tight.

8. A cooking oven (1) according to claim 7, characterised in that said actuator (28) is substantially positioned at the mouth of the first channel (21).

9. A cooking oven (1) according to claim 7, characterised in that said actuator (28) is inserted in said first channel (22A), and comprises a shutter whose section corresponds to that of said first channel (22A) and a mechanism for moving said shutter about a vertical axis.

10. A cooking oven (1) according to one or more of the preceding claims, characterised in that said exhaust means (20) comprise a third channel (24) obtained on an upper portion of said delivery duct (12), said third channel (24) being located downstream of the intersection between the first (21) and second (22) channels and being longer than 250 mm.

11. A cooking oven (1) according to claim 10, characterised in that said exhaust means (20) comprise at least one outlet (25) for releasing the air flowing in said third channel (24) into a space (40) obtained between an upper edge (4A) of the door (4) and a lower region (42) of a front panel (41).

12. A cooking oven (1) according to claim 11, characterised in that said exhaust means (20) comprise a diverter element (26), in particular wedge- shaped, positioned in said third channel (24) to divert the air flow towards said at least one outlet (25).

13. A cooking oven (1) according to one or more of the preceding claims, characterised in that said exhaust means (20) comprise a tubular element (27) associated with the aperture (3 A) in the muffle (3) and adapted to allow the air drawn from within the muffle (3) to reach said second channel (22).

14. A cooking oven (1) according to claim 13, characterised in that said cooling system (10) comprises a cover (60) coupled to the underside of the delivery duct (12), said cover (60) comprising an opening (61) associated with the hole (14) in the delivery duct (12) for allowing the tubular element (27) to be inserted and associated with the aperture (3 A) in the muffle (3).

15. A cooking oven (1) according to one or more of the preceding claims, characterised in that the upper portion of the delivery duct (12) comprises a plurality of coupling means (50) for securing some functional elements of the cooking oven (1) to said delivery duct (12), in particular said coupling means (50) being obtained during the same moulding operation carried out for manufacturing said delivery duct (12).