The present invention relates to a gas burner for a domestic cooking hob.

Domestic cooking hobs in gas cooking appliances are often provided with a flat lid covering the exit opening of the burner. The top end of the burner and/or the lower edge of the lid have a number of openings on the side. Through these openings, the mixture of gas and primary air exits the burner and ignites. These burning flames have the shape of a star. Other forms of burners may have the general shape similar to two coaxial cylindrical or polygonal prismatic tubes, where the mixture of gas and primary air is streaming in a radial direction towards and/or away from a common axis of the tubes, i.e. the hollow interior and in the opposite radial direction outward from the outer tube.

These designs provide some protection for the flames against falling debris and spilled liquids, which may both occur during general cooking or frying operations. Falling particles and spilled liquids have clogged the flame exit holes, through which the mixture of gas and air exits the burner and ignites. By this clogging the operation of the burner is interrupted

It is one object of the present invention to provide an improved design with better protection of the flame against falling debris or spilled liquids.

Accordingly, a gas burner of a domestic cooking hob is disclosed, wherein a top surface of the cover comprises ridges and valleys along a circumferential direction of the cover, wherein inclined partial surfaces of the cover are arranged to connect said ridges and/or valleys, and wherein a respective ridge corresponds to a location being a local maximum of the top surface and a respective valley corresponds to a location being a local minimum of the surface.

The surface of such a cover of a gas burner makes sure that falling particles and spilled liquids follow a predetermined path. When falling particles and spilled liquids have such a predetermined path, the flame exit holes of the gas burner can be arranged so that the effected of falling particles and spilled liquids is reduced. Thereby, the flame exit holes can be protected against clogging. The underlying concept is similar to the idea of a watershed in a mountain landscape, where mountain ridges surround a valley. This valley is open to lower areas. Any water, be it from snow, rainfall or welling from the ground, has to flow in a direction away from the ridges down the mountain slopes to the bottom of the valley and from there to lower areas. Correspondingly, the gas burner described here has on its cover a surface which is arranged as a set of surfaces forming at least one, typically several valleys. These valleys are separated from each other by ridges. Valleys and ridges are connected by sloping surfaces, i.e. surfaces which are not horizontal.

In mathematical terms, a valley of the surface of the cover of the gas burner is a line or an area of the surface which is defined by points which are local minima of the surface. Ridges are defined as lines formed by points which are local maxima of the surface. Both terms, maximum and minimum are defined in terms of the height dimension, i.e. as extrema with respect to the direction of gravity. The direction of gravity is also used as a reference for the definition of a top surface.

Thus, when viewed from the standpoint of gravitational potential energy, ridges have the highest potential energy from all the elements of the top surface of the cover of the gas burner. The gravitational potential energy becomes lower when following the inclined partial surfaces away from a ridge toward a valley. The gravitational potential energy has its lowest values in the valley. In other words, the predetermined path which a fallen particle or spilled liquid will follow can be simply described as downhill.

According to an embodiment, a gas burner according to the above disclosure has flame exit holes which are located on the ridges of the cover.

A possibility to arrange the flame exit holes is by locating them directly along a line of a ridge. Streaming gases which are forming the flame and air following the heat of the flame will be pulled upward. Therefore, falling particles and spilled liquids are being directed away from the flame exit holes. Thus, a protection against clogging can be easily achieved by this selection for the location of the flame exit holes.

According to a further embodiment, flame exit holes are located on a side surface of the gas burner below the top surface of the cover. An arrangement of the flame exit holes of the gas burner on a side surface of a burner will also provide protection against clogging of the flame exit holes by falling particles and spilled liquids, because the arrangement of the surface guides falling particles and spilled liquids from the ridges down the sloping surfaces and from there down the valleys towards the periphery of the burner.

According to a further embodiment, the flame exit holes as described in the previous embodiment are located at least at a predetermined horizontal distance from an intersection of a valley with an outer termination line of the cover.

With such an arrangement of the flame exit holes, the protection of the flame exit holes against clogging by falling particles and spilled liquids is even further improved. Not only do the valleys direct falling particles and spilled liquids towards the periphery of the burner. Even if falling particles and spilled liquids should be directed back towards the gas burner, the likelihood that the falling particles and spilled liquids are being directed back to a flame exit hole is reduced, when the flame exit holes are located away from the area where the valley has its outflow towards the periphery of the burner.

According to a further embodiment, the valleys are inclined in a radially outward direction of the gas burner.

If the valleys are inclined towards an outer periphery of the burner, falling particles and spilled liquids cannot accumulate near the center of the gas burner. Further, this inclination helps in the protection against clogging for the flame exit holes. The falling particles and spilled liquids are directed away from the gas burner in a radial direction.

The inclination causes acceleration of particles and droplets, thus supporting the function of the cover to keep falling particles and spilled liquids away from the flame exit holes by directing them away from the burner itself. In mathematical terms, the absolute minimum of a valley with respect to height is located at the outer circumferential line of the cover of the gas burner, i.e. along the line where the surface of the cover meets the outer side surface.

According to a further embodiment, the ridges are inclined in a radially outward direction of the gas burner. Such an arrangement is also helpful for cleaning of the gas burner and its surroundings, because falling particles and liquids are directed to the outer periphery of the gas burner.

According to a further embodiment, the gas burner has an inner opening. In other words, the gas burner has an annular form, i.e. the shape of a circular or polygonal ring.

According to a further embodiment, the gas burner has a star-shaped footprint.

According to a further embodiment, the gas burner has a convex polygonal footprint. Such a footprint allows for easy cleaning of the gas burner and its surroundings

Further disclosed is a cover for a gas burner according to an embodiment.as described above.

Further disclosed is a cooking hob with a gas burner according to an embodiment as described above. A gas burner according to an embodiment as described above is used in a cooking hob.

Further disclosed is a cooking range with a gas burner according to an embodiment as described above. A gas burner as described above is used in one or more hobs of a cooking range.

Further possible implementations or alternative solutions of the invention also encompass combinations - that are not explicitly mentioned herein - of features described above or below with regard to the embodiments. The person skilled in the art may also add individual or isolated aspects and features to the most basic form of the invention.

Further embodiments, features and advantages of the present invention will become apparent from the subsequent description and dependent claims, taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a perspective view of a gas burner;

Fig. 2 is a perspective view of a different embodiment of a gas burner; Fig. 3 is a perspective view of a further embodiment of a gas burner;

Fig. 4 is a perspective view of a further embodiment of a gas burner; and

Fig. 5 is a perspective view of a further embodiment of a gas burner;

Fig. 6 shows a modification of the gas burner of Fig. 1.

In the Figures, like reference numerals designate like or functionally equivalent elements, unless otherwise indicated.

The top part of a gas burner of a domestic appliance used for cooking is shown in Fig. 1. The gas burner 2 has a cover 1 with a top surface 6. This top surface is formed by eight pairs of surfaces 3. These surfaces are inclined to the horizontal direction. The surfaces 3 are arranged in a manner that they contact each other alternately in ridges 4 and valleys 5. The ridges 4 are the top edges of the surfaces 3, while the valleys 5 are the lower edges of the surfaces 3. The ridges and valleys are extending in a radial direction of the burner 2 which has the shape of a star. The points of this star are rounded.

Falling particles and droplets are indicated by vertical arrows 41. While there are only arrows 41 in Fig. 1 indicating that particles and droplets are hitting ridges, it is understood that particles and droplets can fall on any point of the top surface 6. For simplicity, only arrows are shown which represent particles and droplets that are falling on ridges 4 which are the local maxima, i.e. the highest points of the top surface 6 of the cover 1 of the gas burner 2. The trajectories of particles and droplets hitting the top surface 6 in between the ridges 4 can easily be deducted from the following description which is concerned with particles falling onto the ridges 4. Any particle or droplet falling along one of the arrows 41 will be directed downward the inclined surface 3 as indicated by arrows 42. From there, the particle or droplet will slide further down the valley 5 until it falls from the edge of the top surface 6. The momentum of the particle or droplet will cause that the particle or droplet has a trajectory roughly following the arrow 43, i.e. away from the gas burner 2 and its flame exit holes 31. As can be seen, the flame exit holes 31 are located with their centers along a line of a ridge 4. This will help against clogging of flame exit holes 31 in two ways. First, the ridges 4 make only a small portion of the top surface 6. Thereby, the likelihood of a particle or droplet hitting any flame exit hole 31 is very low. Second, the gas mixture exiting the flame exit hole 31 creates a gas stream in a roughly upward direction. This gas stream together with the heat generated by the flame will help to direct particles or droplets away from the flame exit holes 31.

Fig. 2 shows a perspective view of a gas burner with a similar configuration than the gas burner shown in Fig. 1. The same reference numerals as in Fig. 1 have been used to indicate the respective parts. A main difference between Fig. 2 and Fig. 1 is that the gas burner 2 has an inner opening. In other words, the gas burner of Fig. 2 has an annular footprint. The gas burner 2 is formed basically by an octagonal ring with one or more inner channel(s) (not shown). Such a channel serves to guide the mixture of gas and air to the flame exit opening. The mixture of gas and air is fed to the gas burner from the bottom or from the side (not shown). Again, particles or droplets falling onto the top surface 6 will be directed away from the flame exit holes 31 which are located on the ridges 4 down sloped surfaces 3 and further along valleys 5 until they fall away from the gas burner 2. As can be seen from Fig. 2, valleys 5 may not only be lines, but also surfaces with an inclination that is either in value or in direction different from the inclination of a surface 3. In all embodiments, both the inclined surfaces 3 and the valleys 5 may be formed as a number of different surfaces.

Fig. 3 has a perspective view of a gas burner of the same basic design as the gas burner in Fig. 2. The main difference is that the gas burner of Fig. 3 does not have flame exit holes along the ridges 4. Instead, the gas burner 2 of Fig. 3 has flame exit holes 32 in the vertical outer surface 8 of the outer surface and in the inner surface 9 of the gas burner 2. These surfaces are extending in an upward direction, i.e. in a direction towards the cooking utensil when the gas burner is in use. Again, these flame exit holes are protected from falling particles and droplets because falling particles and droplets will be directed to the valleys 5 and from there to the periphery of the gas burner 2. This protective effect is even enhanced, because the flame exit holes 32 are located below the ridges. By this design, the location of the flame exit holes is far away from the valleys. This is shown by horizontal line 12 which is used to indicate the horizontal distance between flame exit holes 32 and valley 5. This horizontal distance helps to further reduce the likelihood of particles and droplets coming near the flame exit holes 32. It should be noted that in Figs. 3 and 4, the valleys have their lowest point located at the outer periphery of the ring- shaped gas burner. This arrangement will direct most of the falling particles away from the inner opening of the ring and towards the outer periphery of the ring-shaped gas burner.

The gas burner shown in Fig. 4 is very similar to the gas burner of Fig. 3. The main difference is that the flame exit holes 32 are now of a rectangular cross section. In other respects, Fig. 4 corresponds to Fig. 3 with the main exception of the arrangement of the flame exit holes. Further, in Fig. 4 the outer and inner termination lines 10, 11 of the cover 1 are indicated. Dashed lines have been added to indicate either the end of a valley 5 or the edge of a flame exit hole 32 which is located closest to a valley 5. The horizontal line 12 between two vertical dashed lines indicates the horizontal distance between valley 5 and flame exit hole 32.

A further embodiment is shown in Fig. 5 which has the same basic structure and flame exit holes 32 as shown in Fig. 4. Going beyond the configuration of Fig. 4, Fig. 5 now also includes flame exit holes 31 located on the ridges 4. Thus, the embodiment of Fig. 4 can be considered a combination of the embodiments of Fig. 4 and Fig. 2.

Fig. 6 shows a modification of the gas burner of Fig. 1. While the burner in Fig. 1 has a star-shaped footprint, the gas burner of Fig. 6 has an octagonal footprint. In contrast to the embodiments shown in Figs. 2 - 5, the embodiment of Fig. 6 does not have an annular footprint and therefore, no inner opening. Therefore, the ridges should also be inclined towards the periphery of the gas burner.

Any of the embodiments of Figs 2 - 6 may be realized with a cylindrical shape of the gas burner, i.e. with a circular footprint instead of a polygonal outer shape. In the embodiments of Figs. 2 - 5, the inner opening may also be circular instead of polygonal. Instead of the octagon which is shown in Figs. 2 - 6 as footprint of the gas burner, any other polygon may be selected. Regular polygons are preferred, because they match well with round cooking utensils. Depending on the shape of the cooking utensil to be used on the gas burner, other shapes can be used as well. Reference Numerals

1 cover

2 gas burner

3 inclined partial surface

4 ridge

5 valley

6 top surface

8 outer side surface

9 inner side surface

10 termination line

11 termination line

12 horizontal distance 31, 32 flame exit holes

41 arrow indicating falling particle or droplet

42 arrow indicating particle or droplet sliding down an inclined surface

43 arrow indicating particle or droplet sliding down a valley