EP2877787A1

EP2877787A1 - An oven comprising an air circulation fan

Info

Publication number: EP2877787A1
Application number: EP13731046.2A
Authority: EP
Inventors: Burak AKCAN; Servet TURGUT
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2012-07-27
Filing date: 2013-06-10
Publication date: 2015-06-03
Also published as: WO2014016031A1

Abstract

The present invention relates to an oven (1) comprising an outer body, an oven cavity (2) situated in the outer body and wherein the cooking process is performed, a casing (3) produced from ferromagnetic metal material and defining the oven cavity (2), a motor (4) mounted to the casing (3) rear wall, a fan (5) connected to the motor (4) and providing the circulation of the hot air in the oven cavity (2), a shaft (6) providing the fan (5) to be driven by the motor (4), an opening (7) arranged on the casing (3) rear wall and through which the shaft (6) passes and a magnet (8) that is fitted over the shaft (6) and attached to the casing (3) rear wall so as to cover the opening (7).

Description

AN OVEN COMPRISING AN AIR CIRCULATION FAN

The present invention relates to an oven comprising a fan that provides hot air circulation therein.
In ovens with turbo function, the hot air in the oven cavity is circulated by means of a fan, thus providing a homogeneous heat distribution. In the ovens of this type, a fan motor is placed onto the rear wall of the casing that forms the oven cavity and the fan motor rotates the fan in the oven cavity by means of a shaft passing through the casing rear wall. An opening is arranged on the casing rear wall, through which the shaft passes and the diameter of the opening is much larger than the diameter of the shaft due to mechanisms at the end of the shaft such as flange disc, that fix the fan to the shaft. Due to the diameter of the opening being larger than the diameter of the shaft, heat leaks out of the oven cavity, and the leaking heat directly reaches the fan motor and causes the fan motor to overheat and to be damaged. Moreover, in pyrolytic ovens with self-cleaning function at 500 °C, due to heat leakage out of the said opening, the desired temperature level cannot be reached and the oven cannot perform the self-cleaning function. One solution is to use a sealing gasket between the opening and the shaft; however, it is obvious that sealing gaskets cannot withstand high temperatures at this region.
In the International Patent Application No. WO2009091641, a self-cleaning rotisserie oven is disclosed. A bushing is provided between the shaft and the channel through which the shaft rotating the fan motor passes. The inner diameter of the bushing is variable in the axial direction and furthermore an O-ring seal is placed between the bushing and the shaft.
The aim of the present invention is the realization of an oven comprising a fan providing hot air circulation therein and wherein the hot air in the oven cavity is prevented from leaking to the outer environment.
In the oven realized in order to attain the aim of the present invention, explicated in the first claim and the respective claims thereof, the motor of the fan providing the hot air circulation is mounted onto the casing rear wall and the motor shaft is connected to the fan in the oven cavity by passing through an opening larger than the diameter of the shaft, arranged on the casing rear wall. A magnet fitted over the shaft and attached to the casing rear wall so as to cover the opening prevents the hot air in the oven cavity from leaking to outside by serving as a sealing gasket.
The circular disc shaped magnet has a larger diameter than that of the opening and with the effect of magnetic attraction, is attached onto the surface of the casing rear wall facing the motor and all around the opening so as to be concentric with the opening
The shaft hole located at the center of the magnet and through which the shaft passes has a larger diameter than that of the shaft, thus the shaft easily rotates in the shaft hole and the shaft is prevented from rubbing against the magnet and getting abraded.
In the oven of the present invention, amount of heat leakage out of the oven cavity is decreased, energy saving is provided and the fan motor is provided to be protected against high temperatures in the oven.
The oven realized in order to attain the aim of the present invention is illustrated in the attached figures, where:
Figure 1 – is the schematic view of an oven.
Figure 2 – is the partial view of the casing situated in an oven and of a fan motor connected to the casing.
Figure 3 – is the view of detail D in Figure 2.
The elements illustrated in the figures are numbered as follows:

Oven
Oven cavity
Casing
Motor
Fan
Shaft
Opening
Magnet
Shaft hole

The oven (1) comprises an outer body, an oven cavity (2) situated in the outer body and wherein the cooking process is performed, a casing (3) produced from ferromagnetic metal material and defining the oven cavity (2), a motor (4) mounted to the casing (3) rear wall, a fan (5) connected to the motor (4) and providing the circulation of the hot air in the oven cavity (2), a shaft (6) providing the fan (5) to be driven by the motor (4) and an opening (7) arranged on the casing (3) rear wall and through which the shaft (6) passes.
The oven (1) of the present invention comprises a magnet (8) fitted over the shaft (6) and attached to the casing (3) rear wall with the effect of magnetic attraction so as to cover the opening (7).
The magnet (8) surrounds the shaft (6), covers the opening (7), and provides leak-proofing, thus preventing heat in the oven cavity (2) from leaking through the opening (7) and affecting the motor (4). Due to its structure, the magnet (8) is not affected by the oven cavity (2) heat, is not deformed and provides a secure leak-proofing.
In an embodiment of the present invention, the magnet (8) is disc shaped and has a larger diameter than that of the opening (7).
In an embodiment of the present invention, the magnet (8) is attached to the rear surface of the casing (3) rear wall facing the motor (4).
In another embodiment of the present invention, the magnet (8) comprises a shaft hole (9) arranged at the center thereof and having a larger diameter than that of the shaft (6) so that the shaft (6) can easily pass therethrough (for example shaft (6) diameter: 6 mm, shaft hole (9) diameter: 6.5 mm) Thus, the shaft (6) is provided to easily move in the shaft hole (9) while operating. The shaft (6) is prevented from rubbing against the magnet (8) with a hardness value greater than that of the shaft (6) and thus the outer surface of the shaft (6) is prevented from being abraded.
With the effect of magnetic attraction, the magnet (8) is attached to the edge of the circular opening (7), hence to the surface of the casing (3) rear wall facing the motor (4) so as to be concentric with the opening (7) The shaft (6) is passed through the shaft hole (9), the motor (4) is mounted to the casing (3) rear wall and the fan (5) is connected to the end of the shaft (6) inside the oven cavity (2). The shaft (6) passes through the magnet (8) without touching the inner wall of the shaft hole (9). The surface area of the magnet (8) contacting the casing (3) rear wall is much larger than the surface area of the inner wall of the shaft hole (9), thus it is not possible for the shaft (6) to displace the magnet (8) with the effect of magnetic attraction and the concentric positions of the shaft (6) – the shaft hole (9) – the opening (7) are preserved. The cross-sectional area remaining between the shaft (6) and the opening (7) and through which the hot air may leak from the oven cavity (2) to outside is a few hundred mm² (for example 200 – 300 mm²) and in the embodiment of the present invention wherein the magnet (8) covers the opening (7), the cross-sectional area between the shaft hole (9) and the shaft (6) is reduced to a few mm² (for example 4 – 6 mm²). The shaft (6) freely rotates in the shaft hole (9) while the motor (4) is operated. Thus, amount of heat leak through the narrow gap between the shaft (6) and the shaft hole (9) is not significant.
In the oven (1) of the present invention, heat leakage out of the oven cavity (2) is significantly reduced, energy saving is provided and the motor (4) is protected against high temperatures.
It is to be understood that the present invention is not limited by 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

An oven (1) comprising an oven cavity (2) wherein the cooking process is performed, a casing (3) defining the oven cavity (2), a motor (4) mounted to the casing (3) rear wall, a fan (5) connected to the motor (4) and providing the circulation of the hot air in the oven cavity (2), a shaft (6) providing the fan (5) to be driven by the motor (4) and an opening (7) arranged on the casing (3) rear wall and through which the shaft (6) passes, characterized in that a magnet (8) that is fitted over the shaft (6) and attached to the casing (3) rear wall so as to cover the opening (7).
An oven (1) as in Claim 1, characterized in that the magnet (8) that is disc-shaped and has a larger diameter than that of the opening (7).
An oven (1) as in Claim 1 or 2, characterized in that the magnet (8) that is attached to the surface of the casing (3) rear wall facing the motor (4).
An oven (1) as in any one of the above claims, characterized in that the magnet (8) comprising a shaft hole (9) arranged at the center thereof and having a larger diameter than that of the shaft (6).