Patent Application
20160201921
This invention relates in general to a high power gas burner, in particular to dual gas burners for cooking appliances.
Gas burners typically include a burner head having a plurality of outlet ports, i.e. openings that are arranged on the circumference of the burner head through which gaseous fuel such as natural gas or propane fuel is distributed to the outside and further include a burner cover sitting on the burner head to form together with the burner head a combustion chamber.
Dual gas burner for cookers incorporate two gas burners that can be controlled separately and are either arranged radially around each other or on top of each other. For example, US 2014/0238384 A1 describes a dual gas burner where gaseous fuel is ignited at a first burner in a first step and subsequently gaseous fuel is ignited at a second, much larger, burner in a second step. The second, much larger, burner is arranged around the first burner, and can be ignited by means of a carryover slot in the surface of the second burner cover extending between the gas ports of the inner and outer burner.
However, most high power burners are unable to provide a steady and efficient combustion of the gaseous fluid. Also, the flames extending from the ports of the high power burners may extend when not always properly adjusted beyond the bottom of a cooking vessel which might be a pan or a pot that is located on the burner, so that the heat is not equally delivered to the bottom of the cooking vessel.
Therefore, there is a need for a more efficient burner that can be used in large-scale kitchen facilities.
This need is fulfilled by the dual gas burner according to independent claim 1.
The dual gas burner according to the present invention comprises an outer burner and an inner burner, wherein the outer burner having a first gas input and having a first burner head and a first burner cover forming a first combustion chamber, wherein the first burner cover that covers the first burner head, having a conical shaped protrusion in the center extending into the first combustion chamber.
The first burner head may have an annular, substantially flat base and a peripheral wall extending in the vertical direction on the circumference of the substantially flat base and having a plurality of outlet ports through which the gaseous fluid can emerge. The first burner head can be mounted on a burner elbow assembly that provides an inlet for receiving a mixture of gaseous fluid and air, and an outlet extending at an angle to the axis of said inlet. A passage connects the inlet and the outlet for passing a portion of the mixture directly from the inlet to the outlet. The substantially flat base of the first burner head can comprise an opening in the center to accommodate the outlet of the burner elbow in an airtight fashion.
For forming the first combustion chamber the first burner cover that might have a substantially flat and annular shape can be arranged on the first burner head. The first combustion chamber is then delimited by the annular, substantially flat base and peripheral wall of the first burner head and the substantially flat and annular surface of the first burner cover.
Also, the first burner cover has a conical shaped protrusion which might have an annular base and an apex in the center extending into the first combustion chamber and the apex might also be arranged above the center of the inlet. The protrusion and the first burner cover can be formed in one part. However, the conical shaped protrusion can be also mounted to an existing burner cover by means of a mechanical connection which might be a bolt and nut connection, and/or the conical shaped protrusion might be also glued to the burner cover. The conical shape can have a pointed end or a flat end that has a flat surface. The conical shaped protrusion can be also pyramidal having a corresponding base and 3 or more sides. The protrusion can have a height of just a few hundreds of an inch up to one inch and more. Advantageously, the conical shaped structure conditions the high flow, i.e. the flow in the burners that have a high thermal heating power of the gaseous fluid that is streaming into the combustion chamber and eliminates turbulences that would arise when the cone shaped structure would not be installed. This leads to a steadier and more equally distributed flow from the first inlet to outlet ports that are arranged in the first burner head. The resulting flame will be steadier. This avoids uneven heating of the cooking vessel, resulting in a better overall performance of the outer burner.
In one embodiment, the inner burner has a second burner head and a second burner cover forming a second combustion chamber and a second gas input which is independent from the first gas input, wherein the inner burner is arranged on top of the first burner cover.
The surface of the first burner head that is located opposite to the surface of the first burner head and which delimits the first combustion chamber can have any suitable means in its surface to hold the second burner head. The second burner cover might have peripheral walls extending downwards to mate, i.e. engage with the means in the first burner head to form the second combustion chamber. The second burner cover can be simply put on top of the first burner head to form the second combustion chamber. The second burner cover might comprise a peripheral wall having a plurality of outlet ports through which the gaseous fluid can emerge. The second gas input is independent from the first gas input, i.e. separate from the burner elbow assembly. The second gas input might be a pipe-like structure in the geometry of the parts forming the first combustion chamber. The second gas input might therefore extend through the first combustion chamber into the second combustion chamber.
In one embodiment, the second burner head is arranged in a depression of the first burner cover. As described above, with regards to the previous embodiments, the second burner is arranged on top of the first burner cover. Therefore, the first cover comprises a depression, e.g. a recess, a slot, or a cavity in its surface to mate, e.g. to engage with the second burner head. As described above, the second burner head might have peripheral walls extending downwards towards the first burner cover. These peripheral walls that might have the shape of a circular ring might then be placed in a corresponding circular depression on top of the first burner cover for arranging the inner burner on top of the first burner cover.
In another embodiment, the diameter of the outer burner is larger than the diameter of the inner burner. As described above, one purpose of the inner burner is to ignite the much more powerful outer burner. Therefore, the diameter of the inner burner, i.e. the size of the second combustion chamber, can be considerably smaller with respect to the size of the outer burner. Advantageously, a low power inner burner can be operated permanently, or semi-permanently, to instantaneously ignite the much more powerful outer burner, whenever heat from the outer burner is required.
In yet another embodiment, the high power dual burner comprises an igniter adapted to ignite the inner burner. The igniter might simply consist of one or multiple electrodes that are placed near and in coincidence with the inner burner. The electrode can be connected to a spark generating circuit that might be located inside the cooker to generate ignition sparks for igniting the inner burner. For example, when a valve is opened to supply the inner burner with gaseous fuel, the spark generating circuit can be activated in order to provide ignition sparks by the electrode of the inner burner.
In another embodiment, the first burner head comprises annular outlet ports spaced radially on its peripheral wall. As described above, the first burner head may have an annular, substantially flat base and a peripheral wall extending in the vertical direction from the circumference of the substantially flat base and having a plurality of outlet ports through which the gaseous fluid can emerge. Advantageously, by choosing an annular shape, as for example a round geometry for the ports, the gaseous fuel can be burned more efficiently compared to a gas burner that is equipped with rectangular slots that are commonly used in prior art burners. This is in particular achieved if the outlet ports are bored into the peripheral wall so that the complete border of the outlet ports is formed by the peripheral wall of the burner head and not by the combination of burner head and the burner cover as it is the case in the prior art. Also, the annular outlet ports can be arranged in one horizontal plane and being equally spaced from each other. However, the annular outlet ports can be also randomly distributed in the peripheral wall of the first burner head.
In one embodiment, each annular outlet port is inclined in a horizontal direction relative to a horizontal straight line originating from the center of the first burner head and intersecting the annular outlet port. The annular outlet ports might be introduced into the peripheral wall of the first burner as annular openings that form a channel and that are not aligned with a straight line running in the horizontal plane from the center of the peripheral wall towards the outside. All annular outlet ports might be inclined at the same angle following one horizontal direction. However, all annular outlet ports might be also inclined to follow the opposite horizontal direction. Advantageously, the flames originating from these inclined annular outlet ports are kept closer to the peripheral wall of the first burner head than flames originating from annular outlet ports that are orientated relative to the horizontal straight line origination from the center of the first burner head, i.e. which are not inclined. In case all annular outlet ports are inclined at the same angle, the resulting flames originating from the inclined annular outlet ports may combine in one spiral-shaped flame. The diameter of the spiral-shaped flame can be controlled by the inclination angle of the annular outlet ports. For example, angles up to and above 30° might be chosen as inclination angle of the annular outlet ports. By controlling the resulting flame in this manner, the resulting flame can be adjusted so as to not extend, or at least not substantially extend beyond the bottom of a cooking vessel. Therefore, the heat can be more efficiently delivered to the bottom of the cooking vessel.
In one embodiment, each annular outlet port is inclined in the horizontal direction at an angle of 1° to 20° relative to the horizontal straight line originating from the center of the first burner head and intersecting the annular outlet port.
In another embodiment, each annular outlet port is inclined in a vertical direction relative to a horizontal straight line originating from the center of the first burner head and intersecting the annular outlet port. Additionally, or alternatively to an inclination in the horizontal direction each annular outlet port can be also inclined in the vertical direction or y-direction. Alternatively, the annular outlet ports are inclined to point upwards into the direction of the cooking vessel. Advantageously, this also allows controlling the length of the originating flames. For example, an angle in the range of approximately 10° to 45° might be chosen to satisfactorily control the length of the originating flames.
In one embodiment, each annular outlet port is inclined in the vertical direction pointing towards the inner burner at an angle of 14° to 20° relative to the horizontal straight line originating from the center of the first burner head and intersecting the annular outlet port.
In another embodiment, each annular outlet port is inclined in the horizontal direction and in the vertical direction relative to a horizontal straight line originating from the center of the first burner head and intersecting the annular outlet port. Advantageously, by controlling the inclination of the annular outlet ports in both horizontal direction and in the vertical direction of the peripheral wall, the resulting flame can be controlled more efficiently.
In one embodiment, the high power dual gas burner is adapted to perform the following ignition sequence: (i) ignite the inner burner, and (ii) ignite the outer burner by means of the inner burner. As described above, it might be sensible to first ignite gaseous fuel at a smaller burner by electrical means which then ignites gaseous fuel at a second much more powerful power burner. In one embodiment the first burner cover comprises therefore a carryover slot extending over its radial direction adapted to transfer flames from the inner burner to the outer burner for igniting the outer burner. The carryover slot may form a passage for carrying gaseous fuel that might be already ignited along the radial direction from the inner burner to the outer burner to ignite the outer burner.
In another embodiment, the high power dual gas burner has a thermal heating power ranging from 5 KW up to 10 KW.
In the following the high power dual gas burner according to the present invention is further described by reference to the drawings shown in the figures, wherein:
The cross sectional view as shown in
Also, the embodiments shown in
According to one embodiment, all annular outlet ports 12a are inclined at the angle α relative to their respective horizontal straight line 14a originating from the center of the first burner to the annular outlet port 12a. However, the skilled person would know that the annular outlet ports 12 can be also inclined at the same angle following the opposite horizontal direction. In the here shown embodiment, each annular outlet port 12 is inclined in the horizontal direction of the peripheral wall 16 at an angle of 15° relative to the respective horizontal straight line 14 originating from the center of the first burner head 2 and intersecting the annular outlet port 12. However, the skilled person would know that other angles are possible depending on the application of the high power dual gas burner.
In
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The foregoing invention has been described in accordance with the relevant legal standards; thus, the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and do come within the scope of the invention. Accordingly, the scope of legal protection afforded this invention can only be determined by studying the following claims.
