EP1972856A2

EP1972856A2 - Cooking appliance

Info

Publication number: EP1972856A2
Application number: EP08250896A
Authority: EP
Inventors: Nigel Green
Original assignee: Aga Foodservice Group PLC
Current assignee: AGA Rangemaster Group Ltd
Priority date: 2007-03-16
Filing date: 2008-03-14
Publication date: 2008-09-24
Anticipated expiration: 2028-03-14
Also published as: GB0705058D0; EP1972856A3; EP1972856B1

Abstract

A cooking appliance comprises a main body housing at least one oven, a hob mounted on the top of the main body which includes at least one heating region, a heat deflecting baffle which is provided within the main body and which substantially partitions the oven from the hob, one or more airflow control openings which are provided in the baffle and which permit air to flow in a controlled manner from the side of the baffle facing the oven to the side of the baffle facing the hob, a fan which draws air into the region of the main housing on the oven side of the baffle. At least two vents are provided with one on the hob side of the baffle through which air in the hob region can escape the main body, and at least one further vent on the oven side of the baffle through which air can escape the main housing.

Description

This invention relates to improvements in cooking appliances, especially cookers of the range cooker type.
A range cooker is typically a freestanding cooker having one or more ovens, optionally a grill, and a top mounted hob. The earliest range cookers were intended to be fitted into the chimney openings of large houses to replace inefficient open fires. Nowadays they are more likely to be installed in an alcove or perhaps between fitted cabinets in a kitchen as an alternative to a built in appliance.
An ideal cooking appliance would include an oven which does not loose any heat at all through its walls, but in practice all ovens will do this to a lesser or greater extent. This hot air will heat the space surrounding the oven within the main body of the cooker. Vents must be provided in the main body to allow this hot air to escape. If the hot air is not managed correctly any electronic devices within the main housing, such as control circuitry for the ovens, could be damaged. Typically, one or more vents are provided along the upper front edge of the cooker facia to allow hot air to escape. A fan may also be provided at the rear to suck or blow cooling air through the interior and to help scrub the hot air to the outside.
This simple arrangement works well for most cooking appliances. However, the applicant has realised that in some cases there may still exist excessive temperatures. One particular concern is the use of an inductive type hob which will include control electronics that are heat sensitive which could be damaged if exposed to excessive heat. These will often be located at the top of the housing where the hot air rises to meet them and hot spots can occur if care is not taken.
According to a first aspect the invention provides a cooking appliance comprising a main body housing at least one oven, a hob mounted on the top of the main body which includes at least one heating region, a heat deflecting baffle which is provided within the main body and which substantially partitions the oven from the hob, one or more airflow control openings which are provided in the baffle and which permit air to flow in a controlled manner from the side of the baffle facing the oven to the side of the baffle facing the hob, a fan which draws air into the region of the main housing on the oven side of the baffle, and at least one vent through which the air forced across the baffle can escape from the housing.
Preferably at least two vents are provided with one on the hob side of the baffle through which air in the hob region can escape the main body, and at least one further vent on the oven side of the baffle through which air can escape the main housing.
The applicant has appreciated that the provision of a baffle between the oven and the hob, dividing the air is blown by a fan into two airstreams, allows the air flow across the hob better to be controlled. This can allow more accurate cooling or the use of a small, and hence quieter and more efficient, fan. In effect it can provide a cushion of air above the baffle that protects the underside of the hob from hot air rising from the ovens. It also permits heat to be independently scrubbed from the ovens and any part of the hob which requires cooling.
The baffle may comprise a plate, perhaps of metal such as aluminium, which extends from the back of the main oven body to the front to effectively divide the air flow into two paths. It may be disposed generally in a horizontal plane in parallel with the hob.
The single fan, located below the baffle, may be the only source of air flow (other than natural convection currents created by the rising of hot air in the housing) for scrubbing hot air from within the main body. The sizing and number of the baffle openings may be selected to permit a fixed proportion of the air blown by the fan to pass across the underside of the hob and across the ovens. More air may flow below the baffle than above it.
The fan may be located at the rear of the main housing, and may suck air into the housing to blow it across the ovens and baffle.
The openings in the baffle may comprise elongate louvres. They may be formed by stamping or pressing a plate of material to form the baffle. They may comprise elongate slots, and most preferably at least one edge of the slot is deflected out of the plane of the plate to form a ramp which guides the flow of air through the plate and then parallel to the plate. The ramps preferably project into the region above the baffle. In this way, air that is passed through the slot hits the ramp and is steered towards the front of the baffle and then out of the housing.
The spacing of the baffle from the underside of the hob may be between 1cm and 5 cm, or up to 10cm or 20cm. This has been found to provide a uniform flow of air across the underside of the hob.
The main body may be substantially 90cm or 120cm wide and have a depth of substantially 60cm.
The hob may comprise an inductive hob including one or more inductive heating regions or elements. Such hobs are well known and rely on the principle that a ferromagnetic material placed in a rapidly changing magnetic field will heat up due to hysteresis in the material or due to eddy currents that are set up in the material. It may therefore include at least one magnetic coil whose shape defines a heating region below a glass/ceramic upper surface and electronic circuitry for driving and controlling the magnetic field in the coil. It may comprise a self-contained inductive hob which includes all of components required to operate the inductive heating zones with the exception of perhaps the user operable controls. These are typically knobs or buttons that will be located separately on the upper front facia of the cooking appliance.
Other types of hob may be provided, such as halogen hobs or ceramic hobs. These are to a lesser extent more tolerant of heat exposure as they rely on less complex electronics. However, they may still benefit from the improved heat management provided by the baffle. A hob which combines one or more inductive elements with one or more radiant elements may be provided. The hob may be in one piece or may comprise more than one piece. For example a single piece containing 5 inductive elements may be provided or two pieces- one containing inductive elements and the other radiant ones.
The cooking appliance may comprise a range cooker which may be free standing.
It may include a grill and preferably two or more ovens. The grill may be located with the oven(s) below the baffle. The grill and ovens may be insulated with one or more layers of insulating material to help minimise heat loss. The grill may be located within an oven.
The provision of a grill and multiple ovens provides such a high power heat source that a conventional design without the baffle could not keep temperatures at the underside of the hob to such a low level as to stop the electronics of an inductive hob overheating (typically around 80-85oC). The baffle has been found by the inventors to provide an effective solution to this problem.
There will now be described, by way of example only, one embodiment of the present invention with reference to and as illustrated in the accompanying drawings of which:

Figure 1 is a schematic view of a cooking appliance;
Figure 2 is a partial side view of an embodiment of a cooking appliance in accordance with the present invention;
Figure 3 is a view corresponding to Figure 2 showing the flow of air through the cooking appliance when the cooling fan is operated;
Figure 4 is a partial view in perspective from the front of the cooking appliance of Figure 2; and
Figure 5 is a partial view in perspective from the rear of the appliance of Figure 2

As shown in Figures 1 to 5 of the accompanying drawings, a cooking appliance comprises a main cooker housing 10 supported on four legs 20 so as to be free standing. The housing or body comprises an open topped box having front, back and side walls of pressed steel. The box contains a pair of insulated oven cavities 30,40 and a grill cavity 50. Each cavity is in accessible through to a respective opening in the front wall of the housing and is closed by a door (not shown) fixed to the front wall by one or more hinges.
Each oven cavity 30,40 is provided with a heating element at the rear and an (optional) fan 35,45 for circulating air around the oven cavity. The heating element may comprise a gas burner or an electric heating element. In use the heat source heats the air in the oven. A thermostat measures the air temperature in the oven, and feeds the temperature to a controller. The controller regulates the temperature in the oven according to the measured temperature and a temperature demand setting controlled by a knob on the front of the oven housing.
The grill 50 operates in a similar manner, with the key difference being that the heat source is located within the cavity of the grill itself so as to provide direct radiant heating of any food in the grill.
The body 10 is of such a height that a space 60 is defined above the ovens and grill. Hot air that escapes from the ovens will rise up to fill this space.
The top of the housing 10 is covered with a self contained hob unit 70 which defines a worktop and cooking area. This comprises a glass ceramic surface substantially 60cm from front to back and 120cm across. Below the surface is mounted at least one inductive heating element 75 in the form of an electromagnetic coil. The coil is driven with current from an electronic drive circuit 76 which is itself controlled by an electronic control circuit. These electronics have a limited maximum operating temperature of typically 85 degrees centigrade. The applicant has appreciated that this could be exceeded if the hot air rising from the ovens and grill is allowed to impinge upon the electronics without controlling the airflow in the space above the ovens.
To control the air flow, a fan 80 is provided in the rear wall of the oven housing with its axis aligned generally with the middle of the chamber into which the hot air rises. The fan 80 is driven by a drive circuit which is controlled by a temperature sensor (not shown). The control circuit may be set to operate the fan whenever one of the ovens or grill is ON, or perhaps whenever the temperature measured by the sensor exceeds a predefined temperature. The sensor can be located in the space above the ovens 30,40 and grill 50.
The location of the fan can be seen in Figures 2 to 5 of the accompanying drawings. The fan 80 sucks air from outside the oven housing and blows it out into the space 60 above the ovens, creating an airflow towards the front of the housing 10. The bulk of this air is permitted to escape through a set of slots 90 in the front wall of the housing. These slots are located below the level of control buttons and knobs 100 on the front of the cooker, and a heat deflecting shield 110 is provided on the outside of the housing below the control knobs 100. This shield, as is known in the art, ensures the hot air is directed away from the knobs 100.
To further improve the management of the air flow in the cavity a plate like baffle 120 is provided. This lies in a horizontal plane a small distance below the hob and effectively divides the cavity into an upper and lower section. Its front/back and width dimensions therefore equal the internal dimensions of the main housing. to prevent air in the cavity flowing up around the sides of the plate to contact the underside of the hob. It is located above the fan.
The plate baffle 120 does not completely stop air from the fan reaching the underside of the hob. Some flow of air from the lower to the upper section is permitted by way of a set of slots or louvers 125 provided in the plate.
The louvres 125 direct some of the air flow of the lower section into the upper section and encourage it to flow towards the front of the upper section. It can then escape the upper section through a set of slots 130 in the front of the housing above the control knobs and just below the front edge of the hob.
In use the plate baffle 120 keeps the bulk of the hot air flow from the ovens and fan away from the hob yet allows some controlled air flow to pass over and cool the electronics of the hob. This airflow can be seen in Figures 4 and 5 of the accompanying drawings. Because the plate is positioned close to the underside of the hob a good laminar flow can be established for uniform cooling of the underside. A cushion of air is also established above the plate to help isolate the hob from the hot air of the ovens. Alternatively, through careful selection of the location of the slots 125 in the plate 120 the cooling air can be directed to just those regions where it is needed.

Claims

A cooking appliance comprising a main body housing 10 at least one oven 30, 40, a hob 70 mounted on the top of the main body 10 which includes at least one heating region, a heat deflecting baffle 120 which is provided within the main body 10 and which substantially partitions the oven 30, 40 from the hob 70, one or more airflow control openings 125 which are provided in the baffle 120 and which permit air to flow in a controlled manner from the side of the baffle facing the oven 30, 40 to the side of the baffle facing the hob 70, a fan 80 which draws air into the region of the main housing 10 on the oven side of the baffle 120, characterised in that the appliance includes at least two vents through which air forced across the baffle can escape through, one vent 130 being provided on the hob side of the baffle through which air in the hob region can escape the main body, and at least one further vent 90 on the oven side of the baffle through which air can escape the main housing.
A cooking appliance according to claim 1 in which the baffle 120 comprises a plate which extends from the back of the main oven body to the front to effectively divide the air flow into two paths.
A cooking appliance according to any preceding claim in which the fan 80 is located at the rear of the main housing 10, and sucks air into the housing to blow it across the ovens 30, 40 and baffle 120.
A cooking appliance according to any preceding claim in which the openings 125 in the baffle 120 comprise elongate louvres.
A cooking appliance according to any preceding claim in which the spacing of the baffle 120 from the underside of the hob 70 is between 1cm and 5 cm, or up to 10cm or 20cm.
A cooking appliance according to any preceding claim in which the hob 70 comprises an inductive hob including one or more inductive heating regions or elements.
A cooking appliance according to any preceding claim which comprises a range cooker which is free standing.