Patent Description:
Particularly, the present invention relates to a cooking hob comprising a suction opening formed on an upper surface of the cooking hob and suction means configured to suck cooking fumes.

The hoods for domestic environments are now installed in all kitchens present in the homes, as their usefulness in extracting aeriform due to food preparation, i.e., cooking vapours, is now undisputed. It is therefore becoming increasingly important to have hoods for domestic environments that are actually able to eliminate the cooking vapours that are produced during the phases of food preparation.

To this end, hoods have been developed which are able to both suck and discharge the sucked air outside the home by means of suction means, and filter it and introduce it back into the domestic environment.

Among the various hoods on the market there are also the so-called down-draft hoods, which are often integrated in a cooking hob or alternatively in the top of a kitchen cabinet. In particular, the down-draft hood is configured to generate a downward current that is greater than the upward speed of the cooking vapour so that this vapour is sucked towards the cooking hob itself in a vertical downward direction.

For example, a cooking hob comprising a body configured to act as a support for the cooking activity and having an upper surface and an opposite lower surface is known in the state of the art. This cooking hob further comprises at least one cooking zone located at the upper surface of the body.

In addition, the cooking hob of the prior art comprises a suction opening formed in the upper surface of the body and suction means placed in fluid communication with the suction opening and configured to suck cooking fumes.

The suction means of the prior art comprise at least one electric motor configured to generate a flow of cooking fumes through the suction opening. This electric motor has a rotation axis which acts in a plane orthogonal to the upper surface of the body. In other words, the rotation axis of the electric motor is essentially vertical, i.e., perpendicular to the walking surface of a domestic environment in which such a cooking hob is installed.

Examples of such cooking hobs of prior art are known under the trade names of Bora Pure® and Bora Basic® and comprise a single single-suction electric motor and a pair of single-suction electric motors, respectively.

An example of a cooking hob in accordance with the preamble of claim <NUM> is shown in documents <CIT> and <CIT>.

Disadvantageously, during the operation of the cooking hobs of prior art, and in particular during the suction of cooking fumes through the suction opening, the suction means produce a noise which is particularly annoying for the user.

The value of the noise generated during operation has become a parameter to which the manufacturer and/or the user pay great attention, so much so that the energy label must indicate the relative decibel value produced at a given operating speed of the electric motor.

For this reason, there is a strong demand from appliance manufacturers for cooking hobs comprising increasingly quiet suction means.

In this context, the technical objective underlying the present invention is to provide a cooking hob which obviates the drawbacks in the prior art mentioned above.

In particular, it is an object of the present invention to make available a cooking hob comprising suction means which, when operated for suctioning cooking fumes, produce a lower noise level than those of the prior art.

The technical task mentioned and the objects specified are substantially achieved by a cooking hob as defined in claim <NUM>.

Thanks to the invention, it is possible to suck the cooking fumes produced by cooking food while producing an acceptable level of suction noise for the user.

Furthermore, with the invention, it is also possible to divide the cooking fumes within the suction means, thereby enabling a more efficient filtration of the cooking fumes, i.e., a better removal of the fats and vapours present within such cooking fumes.

Further characteristics and advantages of the present invention will become more apparent from the approximate and thus non-limiting description of a preferred, but not exclusive, embodiment of a cooking hob, as illustrated in the accompanying drawings, of which:.

With particular reference to the attached figures, a cooking hob is indicated by the number <NUM>.

Said cooking hob <NUM> comprises a body <NUM> configured to act as a support for the cooking activity.

In fact, as will become clearer in the following, the containers containing the food to be cooked are placed and suitably heated on this body <NUM>.

According to one aspect, the body is preferably square or rectangular in shape and has a predetermined thickness.

This body <NUM> has an upper surface <NUM> and a lower surface <NUM>.

Preferably, the upper surface <NUM>, i.e., the surface intended to act as a support for the containers containing the food to be cooked, is flat.

The upper surface <NUM> and the lower surface <NUM> are opposite each other along a longitudinal direction Y-Y.

Preferably, in use, i.e., when the cooking hob <NUM> is properly installed in a room (not illustrated in the appended figures), such as the kitchen of a domestic dwelling, this longitudinal direction Y-Y is substantially vertical, i.e., it is perpendicular to the walking surface of the room in which the cooking hob <NUM> is installed. Still in use, the lower surface <NUM> of body <NUM> faces the walking surface.

The cooking hob <NUM> comprises at least one cooking zone <NUM> located at the upper surface <NUM> of the body <NUM>. The container containing the food to be cooked is placed on the cooking hob <NUM> at cooking zone <NUM>.

Furthermore, the cooking hob <NUM> comprises at least one suction opening <NUM> formed on said upper surface <NUM> and suction means <NUM> placed in fluid communication with said suction opening <NUM> and configured to suck in cooking fumes. These suction means <NUM> are configured to suck in the cooking fumes produced by cooking the food through this suction opening <NUM>.

Preferably, the cooking hob <NUM> comprises a door <NUM> positioned at the suction opening <NUM>. This door <NUM> is switchable between a first position, in which it allows cooking fumes to be sucked in through the suction opening <NUM>, and a second position, in which the door <NUM> closes the suction opening <NUM>.

The suction means <NUM> comprise a motor fan <NUM> having a rotation axis X-X which lies in a plane parallel to the upper surface <NUM>.

In particular, when the cooking hob <NUM> is correctly installed in a room, this rotation axis X-X is parallel to both the upper surface <NUM> and the walking surface of the room in which the cooking hob <NUM> is installed, i.e., the rotation axis X-X is orthogonal to the longitudinal axis Y-Y.

In the present description, the term "lies in a plane parallel to the upper surface <NUM>" means that the rotation axis X-X of the motor fan <NUM> is substantially parallel to the surface <NUM>, i.e., that the rotation axis X-X lies in a plane that can provide for a variation of +/- <NUM>° with respect to the condition of parallelism. This variability of the parallelism condition may be due, for example, to constructional reasons of the motor fan <NUM>, to assembly reasons or to a design choice.

The motor fan <NUM> extends between a first <NUM> and an opposite second end <NUM> along the rotation axis X-X.

The suction means <NUM> are configured to divide the cooking fumes into a first and a second portion of the cooking fumes directed respectively towards the first <NUM> and the second end <NUM> of the motor fan <NUM>.

It should be noted that due to the arrangement of the rotation axis X-X of the motor fan <NUM> and to the division of the cooking fumes operated by the suction means <NUM>, the suction noise produced by the suction means <NUM> is lower than the corresponding suction noise produced by the cooking hobs of the prior art.

In fact, with particular reference to <FIG>, this figure shows a graph with the flow rate of sucked cooking fumes shown on the abscissa axis and the intensity of the produced noise shown on the ordinate axis.

In particular, said graph shows a first curve <NUM> relative to the cooking hob <NUM> in accordance with the present invention, a second curve <NUM> relative to a cooking hob of the prior art comprising a single single-suction electric motor, and a third curve <NUM> relative to a cooking hob of the prior art comprising a pair of single-suction electric motors.

As can be seen from said graph shown in <FIG>, for flow rate values of the sucked cooking fumes equal to about <NUM><NUM>/h, that is, for a flow rate value of the sucked cooking fumes typical of a normal use of the suction means of a cooking hob, the noise produced by the cooking hob <NUM> in accordance with the present invention is equal to about <NUM> dBA, while the noises produced by the cooking hob of the prior art comprising a single single-suction motor fan and by the cooking hob of the prior art comprising a pair of single-suction motor fans are about <NUM> dBA and <NUM> dBA, respectively.

The difference in value of the cooking hob in accordance with the present invention is therefore equal to <NUM> dBA compared to the cooking hob provided with a single single-suction motor fan and to <NUM> dBA compared to the cooking hob having a double single-suction motor fan.

These differences indicate a significant decrease in the noise perceived by the user with the same volume of air sucked in per hour, thus making the cooking hob <NUM> quieter than the state of the art.

In accordance with the invention, the suction means <NUM> comprise a first <NUM> and a second suction duct <NUM> in fluid communication with the suction opening <NUM> and respectively with the first <NUM> and second end <NUM> of the motor fan <NUM>.

The motor fan <NUM> is configured to suck the first portion of the cooking fumes through the first suction duct <NUM> and the second portion of the cooking fumes through the second suction duct <NUM>.

According to the invention, the fluid dynamic resistance of the first suction duct <NUM> is substantially equal to the fluid dynamic resistance of the second suction duct <NUM>. In the maximum preferred case, the fluid dynamic resistance of the first suction duct <NUM> is equal to the fluid dynamic resistance of the second suction duct <NUM>.

Still preferably, the length and the passage section of the cooking fumes of the first <NUM> and of the second suction duct <NUM> correspond to each other.

Thanks to the correspondence between the fluid dynamic resistance of the first suction duct <NUM> and the fluid dynamic resistance of the second suction duct <NUM>, the distribution of the cooking fumes between the first <NUM> and the second suction duct <NUM> is symmetrical. In other words, the first portion of the cooking fumes corresponds to the second portion of the cooking fumes. In other words, the cooking fume flow rate in the first suction duct <NUM> corresponds to the cooking fume flow rate in the second suction duct <NUM>.

In order to obtain the desired suction, the motor fan <NUM> comprises an electric motor and an impeller.

According to one aspect, the impeller is mechanically connected to the shaft of the electric motor. In this way, the rotation of the motor shaft of the electric motor causes the impeller to rotate and to thus be able suck the cooking fumes.

The impeller, which preferably consists of a single piece made by moulding, comprises a first half-part 51a and a second half-part 51b arranged at the first <NUM> and the second end <NUM> of the motor fan <NUM>, respectively.

The first half-part 51a of the impeller is configured to suck the first portion of the cooking fumes through the first suction duct <NUM>, and the second half-part 51b of the impeller is configured to suck the second portion of the cooking fumes through the second suction duct <NUM>.

In accordance with the invention, the cooking hob <NUM> comprises a pair of covering casings <NUM> connected to each other so as to define a housing <NUM>. The motor fan <NUM> is arranged in the housing <NUM>. The motor fan <NUM> is therefore supported and protected by the covering casings <NUM>.

According to the invention, the covering casings <NUM> define the first <NUM> and the second suction duct <NUM>. In other words, the shape and dimensions of the first <NUM> and second suction duct <NUM> are defined by the coupling between the covering casings <NUM>.

In accordance with the preferred embodiment of the invention, the cooking hob <NUM> comprises an operating unit <NUM> for the operation of the cooking hob <NUM>, for the control thereof and for the outflow of cooking vapours through first <NUM> and the second suction duct <NUM>.

The operating unit <NUM> is further configured to contain at least one heating element capable of heating the at least one cooking zone <NUM> and a command and control electronics of the cooking hob <NUM>.

By means of the operating unit <NUM> the user can selectively adjust the heating of the cooking zone <NUM> and operate the suction means <NUM>. In other words, by means of the operating unit <NUM> it is possible to operate the motor fan <NUM> and to adjust the rotation speed of said motor fan <NUM>.

The operating unit <NUM> is per se known to the person skilled in the art and will therefore not be described further.

This operating unit <NUM> is arranged below the body <NUM> of the cooking hob <NUM>. Preferably, this operating unit <NUM> is constrained to the lower surface <NUM> of the body <NUM>.

According to a preferred aspect, the covering casings <NUM> are arranged and constrained below the operating unit <NUM> and at least one covering casing <NUM> is reversibly constrained to the operating unit <NUM> to allow access to the housing <NUM>. By removing one of the covering casings <NUM>, it is possible to carry out maintenance activities on, for example, the motor fan <NUM>. In other words, at least one covering casing <NUM> is reversibly constrained to the operating unit <NUM> to allow the motor fan <NUM> to be reached.

In accordance with the preferred embodiment of the invention, a covering casing <NUM> is reversibly constrained to the operating unit <NUM>, while the other covering casing <NUM> is stably constrained to the operating unit <NUM>.

In an alternative embodiment both covering casings can be provided as reversibly constrained to the operating unit <NUM>.

In the portion of the housing <NUM> close to the covering casing <NUM> stably constrained to the operating unit <NUM>, the power supply unit (not illustrated in the accompanying figures) of the motor fan <NUM> is housed.

Still in accordance with the invention, the cooking hob <NUM> comprises a first 8a and a second filtering group 8b arranged in the housing <NUM> upstream of the respective first <NUM> and second suction duct <NUM> so as to filter the fats and the vapours that are present respectively in the first and second portion of the cooking fumes. Advantageously, the first and second portions of the cooking fumes are filtered separately, thus allowing a better filtration efficiency of the cooking fumes.

Preferably, the first 8a and the second filtering group 8b comprise respectively a grease filter comprising a metal grid and an activated carbon filter. The grease filter and the activated carbon filter are familiar to the person skilled in the art and will therefore not be described further.

In accordance with the preferred embodiment of the invention, the suction means <NUM> comprise a suction chamber <NUM> in fluid communication with the suction opening <NUM>. This suction chamber <NUM> is located downstream of suction opening <NUM>. Preferably, the suction chamber <NUM> is defined by the operating unit <NUM> and the covering casings <NUM>.

Said suction chamber <NUM> has a first <NUM> and a second outlet <NUM> in fluid communication, respectively with the first <NUM> and the second suction duct <NUM>. The suction chamber <NUM> is therefore located upstream of the first <NUM> and the second suction duct <NUM>. In other words, the suction chamber <NUM> is interposed between the suction opening <NUM> and the first <NUM> and the second suction duct <NUM>.

The separation of the cooking fumes between the first and the second portion of the cooking fumes occurs at the suction chamber <NUM>. In fact, the first portion of the cooking fumes passes from the suction chamber <NUM> to the first suction duct <NUM> through the first outlet <NUM>, while the second portion of the cooking fumes passes from the suction chamber <NUM> to the second suction duct <NUM> through the second outlet <NUM>. Preferably, the surface extent of the first outlet <NUM> corresponds to the surface extent of the second outlet <NUM>.

The first 8a and the second filtering group 8b are placed at the first <NUM> and second outlet <NUM> of the suction chamber <NUM>, respectively. Preferably, the first 8a and the second filtering group 8b are interposed between the suction chamber <NUM> and, respectively, the first <NUM> and the second suction duct <NUM>.

Still in accordance with the preferred embodiment of the invention, the covering casings <NUM> when constrained define an exhaust outlet <NUM> in fluid communication with the motor fan <NUM>. The suction means <NUM> are configured to expel the cooking fumes through this exhaust outlet <NUM>. The cooking fumes sucked through the suction opening <NUM> are then removed through the exhaust outlet <NUM>.

Preferably, the covering casings <NUM>, when constrained, define an exhaust duct <NUM>. Said exhaust duct <NUM> is configured to place the motor fan <NUM> and the exhaust outlet <NUM> in fluid communication. In other words, this exhaust duct <NUM> is located downstream of the motor fan <NUM> and upstream of the exhaust outlet <NUM>.

In accordance with the preferred embodiment of the invention, the path of the cooking fumes from the suction opening <NUM> to the exhaust outlet <NUM> provides for the passage of the cooking fumes in the suction chamber <NUM> through the suction opening <NUM>, dividing the cooking fumes into a first and a second portion of the cooking fumes at the suction chamber <NUM>, the reaching of the first end <NUM> of the motor fan <NUM> by the first portion of the cooking fumes through the first suction duct <NUM>, the reaching of the second end <NUM> of the motor fan <NUM> by the second portion of the cooking fumes through the second suction duct <NUM> and, finally, the rejoining of the first and second portion of the cooking fumes in the exhaust duct <NUM>, before expulsion through the exhaust outlet <NUM>.

Claim 1:
A cooking hob (<NUM>) comprising:
- a body (<NUM>) configured to act as a support for the cooking activity and having an upper surface (<NUM>) and a lower surface (<NUM>);
- at least one cooking zone (<NUM>) located at the upper surface (<NUM>) of the body (<NUM>);
- a suction opening (<NUM>) formed on said upper surface (<NUM>);
- suction means (<NUM>) placed in fluid communication with said suction opening (<NUM>) and configured to suck cooking fumes;
wherein:
- said suction means (<NUM>) comprise a motor fan (<NUM>) having a rotation axis (X-X), said motor fan (<NUM>) extending between a first (<NUM>) and an opposite second end (<NUM>) along said rotation axis (X-X);
- said suction means (<NUM>) comprise a first (<NUM>) and a second suction duct (<NUM>) in fluid communication with the suction opening (<NUM>) and respectively with the first (<NUM>) and the second end (<NUM>) of the motor fan (<NUM>)
- said suction means (<NUM>) being configured to divide the cooking fumes into a first and a second portion of the cooking fumes directed respectively towards the first (<NUM>) and the second end (<NUM>) of the motor fan (<NUM>), said motor fan (<NUM>) being configured to suck the first portion of the cooking fumes through said first suction duct (<NUM>) and the second portion of the cooking fumes through said second suction duct (<NUM>);
- the axis of rotation (X-X) lies in a plane parallel to this upper surface (<NUM>)
- the fluid dynamic resistance of said first suction duct (<NUM>) being substantially equal to the fluid dynamic resistance of said second suction duct (<NUM>)
characterizing in that it comprises:
- a pair of covering casings (<NUM>) connected to each other so as to define a housing (<NUM>), said motor fan (<NUM>) being arranged in the housing (<NUM>), said pair of covering casing (<NUM>) defining the first (<NUM>) and the second suction duct (<NUM>);
- a first (8a) and a second filtering group (8b) arranged in the housing (<NUM>) upstream of the respective first (<NUM>) and second suction duct (<NUM>) so as to filter the fats and the vapours that are present respectively in the first and second portion of the cooking fumes.