NZ549610A - Oven with concealed fan shroud - Google Patents

Abstract

An oven that has a concealed fan for circulating air to aid the cooking of food is disclosed. The oven has a cooking chamber 4 with a base 7, roof, and side walls 5, inside an external shell. A fan chamber is defined is defined between an internal rear wall 6 and an external rear wall 20 of the cooking chamber. The internal rear wall joins to the roof and base, but not to the side walls, and includes a centrally located air transfer opening 9. A baffle wall 16 in front of the internal wall is connected to the floor and there is a gap between the top of the baffle wall and the roof, creating a top slot. The internal wall and baffle wall are connected at the sides defining an antechamber. A fan located behind the internal rear wall draws air through the top slot, into the antechamber, and through the air transfer opening and expelling the air through the gaps between the internal and baffle wall sides and the sides of the cooking chamber.

Description

10052464003* ;5*96 10 NEW ZKALAND PATKNTS ACT, 1953 COMPLETE SPECIFICATION OVEN WITH CONCEALED FAN SHROUD We, FISHER & PAYKEL APPLIANCES LIMITED, a company duly incorporated under die laws of New Zealand of 78 Springs Road, East Tamaki, Auckland, New Zealand, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: Intellectual Prooerty Office of N.Z. 3 1 AOb" 2008 I -1 IV E nj FIELD OF THE INVENTION The present invention relates to convection ovens with an integral fan to aid in the circulation of heated air for cooking purposes.

DESCRIPTION OF THE PRIOR ART It is known in the prior art to improve the cooking efficiency in ovens by reducing the uneven distribution of hot air and the temperature differences within the oven cooking cavity by means of a fan that is located within, or which is located so as to affect the air in the oven cavity. Ovens employing this technique are commonly called convection ovens. Usually the fan is located behind the rear wall of the oven cavity, in a central position. The fan is usually protected by a shroud or similar that is located in an aperture in the rear wall directly in front of the fan, the shroud having slots or grooves that allow the fan to circulate the air inside the oven cavity. In use, air is drawn in from the oven cavity through apertures in the shroud, and then driven back into the oven cavity by the fan, either through other apertures in the shroud, or through other apertures located further away from the shroud - e.g. in the rear wall, or in the side walls of the cooking cavity. An example of this arrangement is shown in Figure 1.

US 6,718,965 discloses a baffle panel for an oven, which is located in front of a shroud similar to that described above. The baffle panel acts as a flue spout, and does not substantially conceal or overlap with the rear wall of the cooking cavity.

US 5,568,803 discloses an oven that has a shaped baffle plate located in front of the fan and rear wall of the oven cooking cavity. The baffle plate is substantially the same size as the rear wall of the cooking cavity, with openings at the sides to allow air from the fan to enter the coolong cavity. Air is drawn into the fan from behind the fan as well as through a central shroud aperture, and the airflow path is not exclusively through the central shroud apertures. The baffle plate also contains holes that enhance the airflow.

EP 1,512,919 discloses an air conditioning unit where air is drawn in from behind the fan (i.e. from an outside area), the conditioned air then being driven into a room or similar area from side apertures in the air conditioning unit.

Prior art systems such as those referred to above can have disadvantages. The shroud inlet apertures can require guarding. This guarding restricts the open area of the apertures and can be unsightly. Also, once cooking residues start to accumulate on either the fan blades, the shroud, or both, this can look messy and unhygienic. Furthermore, the shroud is usually difficult to clean because of the guarding and the nature of aperture pattern.

As well as this, with units of the type that draw air in from an area outside the heated cooking cavity, this air may be cooler than the air already circulating in the cooking cavity, and heating this air to the required temperature can add to die thermal load of the heating elements that arc keeping the cooking cavity at the user required temperature. These types of design can also add complexity to the overall oven design.

It is an object of the present invention to provide an oven that goes some way towards overcoming the above disadvantages, or which will at least provide the public with a useful choice.

SUMMARY OF THE INVENTION Accordingly in a first aspect the present invention may be said to consist in an oven for cooking food comprising: an external shell having a front side with an opening formed therein, a cooking chambcr located within said external shell, having a front opening co-located with said external shell front opening, a controllable heating source provided within said external shell for supplying sufficient heat to the inside of said chambcr to cook food positioned therein, a door moveable between a closed position closing the open front of said external shell and said chamber, and an open position, said cooking chamber including side walls, a base, a roof, an internal rear wall and an external rear wall, said internal rear wall including an air transfer opening positioned substantially centrally, said external rear wall running between and connected to said side walls, said roof and said base, to define with said internal rear wall a fan chambcr behind said air transfer opening, said internal rear wall running between, and connected to, said base and said roof, a baffle wall, located in front of said internal rear wall and connected to said floor, said baffle wall sized such that a top slot is created between said roof and the top edge of said baffle wall, with a cooking space in front of said baffle wall, said internal rear wall and said baffle wall defining an antechamber closed at the sides and bottom, open to the cooking chambcr at the top, and open to said fan cavity through said air transfer opening, said internal rear wall and said baffle wall being narrower than said cooking chamber and leaving a slot at cither side for air flow between said fan chamber and said cooking space, a fan, located behind said internal rear wall, for drawing air through said air transfer opening, in use, said fan drawing air from said cooking space through said top slot into said antechamber, through said air transfer opening in said internal rear wall into said fan chamber, and then expelling said air back into said cooking chamber through said slots at either side.

Intellectual Property Office of M.Z. \ 8 SEP 2006 r p r. p i \/ p n Preferably said rear corners of said external rear wall are concave.

To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

The invention consists in the foregoing and also envisages constructions of which the following gives examples.

BRIEF DESCRIPTION OF THE DRAWINGS One preferred form of the present invention will now be described with reference to the accompanying drawings.

Figure 1 shows a partial plan view of an oven construction of the prior art type, with air from the cooking cavity being pulled through a central shroud opening by a fan, and then expelled back into the cooking cavity via a pair of vertical slots at each side of the rear wall.

Figure 2 shows an oven to which the present invention can be applied.

Figure 3 is a perspective view of a cooking chambcr which can be used with the oven of Figure 2, with the roof of the chamber not shown for clarity. The Figure shows a baffle wall located towards the rear of the cooking chambcr, an internal rear wall behind the baffle wall, an external rear wall behind the internal rear wall, and a shroud in the internal rear wall shown as hidden detail. Details of the airflow within the oven are also shown.

Figure 4 is a plan view of the oven of Figure 2, showing airflow over the top of the baffle wall, and then through the shroud into the fan, with the air then expelled back into the cooking cavity via slots at each side of the rear wall.

Figure 5 is a side view of the oven of Figures 3, 4 and 5.

DETAILED DESCRIPTION OF THE INVENTION The preferred embodiment of the invention shall now be described with reference to Figures 2-5.

An oven 1 is shown in Figure 2. The basic structure of the oven 1 is an outer casing, external shell, or cabinet 2 with an open front face. The oven 1 can be of the type that is fitted independently, or which may be used as part of a range, with a separate cooktop located above the oven 1, for heating pots and pans. In the embodiment shown in the Figures, the oven is of the independent type. The oven of the present invention is suitable for either gas burner or electric element cooking, or both.

In the preferred embodiment of the present invention, an oven cavity or cooking chamber 4 is nested inside the outer casing 2. An example of the preferred embodiment of the cooking chamber 4 is shown in Figure 3. The cooking chamber 4 has an open front, two internal side walls 5 (right and left), an internal rear wall 6, an external rear wall 20, a base 7 and a roof 8. It should be noted that the external rear wall 20 is not on the outside of, or external to, the oven 1, it is the outside or external rear wall of the cooking chamber 4.

The external rear wall 20 is connected to the side walls 5 and the base and roof 7, 8 to form closed or sealed seams. The internal rear wall 6 runs the height of the cooking cavity 4, and is connected to the base 7 and roof 8. The internal rear wall 6 is of slightly lesser width than the external rear wall 20 (and therefore the width of the cooking chamber 4). The edge portions 21 of the internal rear wall are bent slightly toward the open front of the cooking chambcr 4. This bend and the relative dimensions of the internal rear wall 6 and cooking chamber 4 leaves two narrow gaps or slots 11 between the side walls 5 and the edge portions 21, running from the roof 8 to the base 7.

A fan 10 is located behind the internal rear wall 6, between the internal rear wall 6 and the external rear wall 20. The fan 10 is located at a substantially central position in the internal rear wall 6. The fan 10 is driven by a motor 15. The motor 15 is located behind the internal rear wall 6.

The preferred embodiment of the internal rear wall 6 includes an opening 23, substantially the same diameter as the fan 10, and located directly in front of the fan 10. A shroud 9 fills or closes the opening. The preferred form of the shroud 9 is a plate that includes a plurality of perforations, louvers, or both passing through it (generally referred to as apertures). It should be noted that in alternative embodiments, the central area of the rear wall 6 can be perforated or louvercd directly to form a 'shroud' area. This alternative removes the requirement for forming a central opening which is then closed by adding a shroud. Whichever construction is used, the result is to form an air transfer opening in the internal rear wall.

As described above, the external rear wall 20 runs between, and is connected to, the side walls 5, the roof 8 and the base 7, with the internal rear wall 6 in front of the rear wall, the fan located in this space. The space or chamber defined by these elements, located behind the air transfer opening, is referred to in this specification as the fan chamber.

A baffle wall 16 is located in the cooking cavity 4, directly in front of the internal rear wall 6, and spaced a small distance from internal rear wall 6. The baffle wall 16 is preferably substantially the same size as, but slightly shorter than, the internal rear wall 6. The baffle wall 16 is narrower than the width of the cooking cavity 4. The slots 11 pass each side of the baffle wall 16. When the baffle wall 16 is in place, a top slot 17 remains between the top edge of the baffle wall 16 and the roof 8 of the cooking chamber 4.

The internal rear wall 6 and the baffle wall 16 define an antechamber, closed at the sides and bottom, open to the cooking chamber 4 at the top, and open to the fan cavity through the air transfer opening or shroud 9, As described above, the edge portions 21 of the internal rear wall 6 are bent slightly forward. It is preferred that the outer edges of the edge portions 21 are connected to the side edges of the baffle wall 16 to form closed seams.

In use, air is drawn over the top of the baffle wall 16, through the top slot 17. Air then flows down between the baffle wall 16 and the internal rear wall 6 and into the fan 10 through the shroud 9. The air is then expelled from the sides of the fan 10, between the internal rear wall 6 and the external rear wall 20. The air then re-enters the cooking cavity 4 via the slots 11. The space between the internal rear wall 6 and the external rear wall 20 can include a heating element or similar (not shown). However, this heating element can be located elsewhere in the oven 1 as required.

In the preferred embodiment, the rear corners 22 of the cooking cavity 4 are curved or concave. The corners 22 arc cither fitted with curved elements placed at the rear corners of the cooking cavity 4, running from floor to roof, or the external rear wall 20 is bent and shaped to form the curved corners 22. The angled forward edge portions 21 and the curved corners 22 have the effect of allowing air expelled from the fan 10 to flow smoothly around the rear corners of the cooking cavity 4 and back into the main area of the cooking cavity 4, with reduced turbulence to disrupt the airflow.

The baffle wall 16 as described above has the advantage of shielding the internal rear wall 6 and the shroud 9 from food spillages or similar (e.g. grease spitting, etc). Any food spillages will hit the baffle wall 16. However, as the baffle wall 16 is smooth and it has no apertures or other difficult to clean features, it can be easily wiped clean when cleaning is required.

WHAT WE CLAIM IS: 1. An oven for cooking food comprising: an external shell having a front side with an opening formed therein, a cooking chamber located within said external shell, having a front opening co-located with said external shell front opening, a controllable heating source provided within said external shell for supplying sufficient heat to the inside of said chamber to cook food positioned therein, a door moveable between a closed position closing the open front of said external shell and said chamber, and an open position, said cooking chamber including side walls, a base, a roof, an internal rear wall and an external rear wall, said internal rear wall including an air transfer opening positioned substantially centrally, said external rear wall running between and connected to said side walls, said roof and said base, to define with said internal rear wall a fan chamber behind said air transfer opening, said internal rear wall running between, and connected to, said base and said roof, a baffle wall, located in front of said internal rear wall and connected to said floor, said baffle wall sized such that a top slot is crcatcd between said roof and the top edge of said baffle wall, with a cooking space in front of said baffle wall, said internal rear wall and said baffle wall defining an antechamber closed at the sides and bottom, open to the cooking chamber at the top, and open to said fan cavity through said air transfer opening, said internal rear wall and said baffle wall being narrower than said cooking chamber and leaving a slot at either side for air flow between said fan chambcr and said cooking space, a fan, located behind said internal rear wall, for drawing air through said air transfer opening, in use, said fan drawing air from said cooking space through said top slot into said antechamber, through said air transfer opening in said internal rear wall into said fan chamber, and then expelling said air back into said cooking chambcr through said slots at either side. 2. An oven as claimed in claim 1 wherein the rear corners of said external rear wall are concave.

Claims (1)

1. CLAIMS » Intellectual Property Office of N.Z. 18 SEP 2006