The present invention is directed to a gas cooking assembly and to a hob comprising the same.

Although many experienced cooks, irrespective of for domestic cooking or for commercial or gastronomical cooking, prefer gas cooking devices over electric or inductive cooking hobs, gas cooking devices often have difficulties to compete with glass ceramic hobs with electric or inductive heating in terms of ease and comfort of ease use, particularly under the aspect of flexibility and cleanability.

Thus gas cooking fields often require more effort for cleaning because, in contrast to electric or inductive glass ceramic hobs, a gas cooking field usually consists of several individual components, which when cleaning the hob have to be disassembled, individually cleaned, and then again reassembled.

EP 2 737 250 B1 addressed such problem by providing for a burner assembly having a central gas supply feeding a flame spreader which is fixedly connected to a grate for supporting a cooking vessel. While the grate either may be supported directly by the burner or may comprise supports legs that are connected to a base ring that rests on the cooktop surface, in all embodiments the burner has a centrally located feed duct that connects to a gas supply provided in the cooktop surface.

A similar approach is shown in EP 2 589 879 A1 which discloses a gas burner assembly in which a burner crown and a burner cap are attached to a cookware support so as to integrate the burner and the cookware support as a one-part-piece to facilitate handling. Similarly as in EP 2 737 250 B1, also the burner suggested in EP 2 589 879 A1 comprises a centrally located feed duct that connects to a gas supply provided in the cooktop surface. When it comes to flexibility, while in the field of glass ceramic hobs with electric or inductive heating it is quite common to provide for variable cooking zones, the size and/or shape of which can be varied, also in the field of gas cooking devices several attempts were made to provide for variable cooking zones.

Thus, in U.S. Pat. No. 6,017,211 A a gas cooking appliance was suggested having a cooktop surface and a plurality of gas burners, wherein for each burner there is provided a gas outlet in the cooktop surface, and wherein each burner comprises a circular burner nozzle having radial gas outlets, a gas inlet that is located off-center with respect to the circular shape of the burner nozzle, and two igniter openings for receiving an igniter fixedly provided in the cooktop surface, so that by rotating the burner nozzle by 180° about the gas inlet the position of the burner can be changed.

EP 0 677 705 A2 discloses a gas hob with a removable burner head which can be inserted in different positions, i.e. rotated by 90° or 180, so as to assume different working positions.

In EP 2 592 355 A1 and in EP 2 896 886 A1 there are disclosed hobs wherein a burner unit is mounted on a mechanical motion unit, in particular a motor driven turntable, so that the position of the heating element can be altered.

Furthermore, in US 20170067632 A1 there is disclosed a burner assembly for a cooktop having ring-shaped burner nozzle to which gas is provided by an eccentric gas supply along the ring, wherein the ring can be rotated about the gas supply to assume various positions.

While the above solutions that rely on mechanical motion units are quite complex and thus expensive to manufacture and, due to its mechanical components, are prone to wear and failure, the other solutions are disadvantageous in terms of handling and ease of use, since for moving the burner they all require a grate for supporting cooking vessels to be removed, the burner to be dislocated, and the grate to be reinstalled.

In view of the above, it is to be seen that there is room for improvement. The present invention aims to provide for a gas cooking assembly that provides for improvements in terms of handling and ease of use, and which particularly addresses both the issues of flexibility and cleanability.

In accordance with the present invention the above object is solved by a gas cooking assembly which comprises:

(a) a base part comprising:(a1) a cooktop surface;(a2) a gas outlet in the cooktop surface; and(a3) an ignition source in the cooktop surface; and

(b) an upper part comprising:(b1) at least one foot for supporting the upper part on the cooktop surface;(b2) a grate for supporting a cooking vessel;(b3) an annular flame spreader; and(b4) a gas inlet at the bottom side of the flame spreader;

wherein the upper part is an integral unit that is removable from the base part, wherein when the upper part is connected to the base part, the gas inlet of the upper part connects to the gas outlet of the base part.

The present invention thus provides for a burner assembly in which the upper part with the grate and the flame spreader is an integral unit which as a whole can be removed from and reinstalled to the base part, which facilitates handling of the device during removal, installation and cleaning, since only a single component is to be manipulated. Furthermore, given that the sole burner parts that are provided in the base part are the gas outlet and the ignition source, these elements can be provided in the cooktop surface in a manner that allows easy cleaning of the base part when the upper part has been removed.

The cleanability of the assembly can be further improved by adequate selection of the materials for the individual components. In that respect it should be noted that although the upper part is designed as an integral unit, the flame-spreader can be made from a different material than the grate or a burner cap that is formed with the grate. Thus, while the flame-spreader advantageously can be made for example of aluminum which facilitates high precision forming of the flame-spreader, such as to provide for minute gas outlet openings, the grate and any components formed therewith, such as a burner cap and/or legs for supporting the upper part, can be formed as a molded part which is provided with an easy to clean coating, such as an enamel coating.

Given that the sole elements to be connected when installing the upper part on the base part are the gas inlet and the gas outlet, the base part can be used with different upper parts, i.e. with upper parts that differ in the size and shape of the grate and/or that differ in the gas throughput of the flame spreader, i.e. in the power of the burner, but which all have a gas inlet of a common size and shape.

Furthermore, due to the flame spreader being an annular element, the gas inlet being not centrally located but eccentrically along the annular shape of the flame spreader, which allows positioning the upper part in different orientations with respect to the base part. Thus, the present invention for a gas cooking assembly which allows rotating the upper part, which when using more the gas cooking assembly with at least one further burner allows combining adjacent gas cooking zones so as to adapt the size and shape of the cooking zone to cooking vessels of different size and shape.

In particular, the grate may comprise an annular disk which interposes the flame spreader and which carries a plurality of bars for supporting a cooking vessel. In such embodiments, the annular disk of the grate provides a stable basis that interconnects the plurality of bars, which thus can be freely placed at any angular position of the annular disk, such as in a regular pattern of four bars that are arranged in a cross-like fashion, i.e. when measuring from a first bar at 90°, 180° and 270°. Of course also any other number and/or orientation of the bars is possible.

In such latter embodiments, a plurality of legs can be attached to the annular disk, wherein each leg has a foot for supporting the upper part on the cooktop surface. The grate thus can be configured as a stable stand-alone support, wherein the grate not only carries the cooking vessel, but also provides for the structural elements by which the upper part of the burner assembly an any cooking vessel placed thereon is supported by the cooktop surface.

In a particularly preferred embodiment, the bars for carrying a cooking vessel extend outwardly beyond the annular disk and merge into the legs, in which manner there can be provided for a large and stable supporting surface for carrying a cooking vessel and which at the same time provides for maximum stability for the standing of the legged grate on the cooktop surface, since the legs thus can be placed at a maximum distance to each other.

Advantageously, the legs can be are sized to provide for a distance between the flame spreader and the cooktop surface, so that the legs are the only elements of the upper part that are in contact with the cooktop surface, in which manner most part of the cooktop surface below the upper part remains free and thus is easy to clean after removal of the upper part.

The flame spreader can have a generally U-shaped cross-sectional shape having inner and outer annular walls with a plurality of recesses along the upper edge of the inner and/or outer wall. Together with a corresponding capping element that closes the U-shape at the top side, such as the bottom side of the grate to which the flame spreader directly abuts, or a cap ring which is interposed between the flame spreader and the grate, the internal volume of the U-shape forms a gas distribution chamber by which gas is passed from the gas inlet to the plural burner openings that are formed as recesses along the upper edge of the inner and/or outer wall. While the flame spreader thus can be configured selectively as a burner nozzle comprising a circular outwardly directed gas flow, as a burner nozzle comprising a circular inwardly directed gas flow, or as a burner nozzle that ejects two concentric flame rings, configuring the respective outlet openings as recesses along the upper edge of the inner and/or outer wall facilitates manufacturing of the flame spreader.

As already was mentioned above, the flame spreader can directly abut against the bottom side of the grate, in which case the grate also acts as cap element for closing the U-shape of the flame spreader.

In the alternative, there also can be provided a dedicated cap ring which is interposed between the flame spreader and the grate, wherein the cap ring rests on the upper edge of the inner and outer walls of the flame spreader.

Irrespective of whether the flame spreader abuts against the bottom side of the grate or a dedicated cap ring is interposed between the flame spreader and the grate, the grate or cap ring serves to close the upper open side of the U-shaped flame spreader so as to form a distribution chamber to which gas is supplied via the gas inlet and from which gas is ejected via the plurality of openings that are provided by the recesses along the upper edge of the inner and/or outer wall. Providing a dedicated cap ring can be advantageous in terms of controlling gas exit from the flame spreader. That is, for example when the grate is formed of enameled metal, the bottom side of the grate might not be sufficiently even to prevent uncontrolled gas exit at the location of contact between the flame spreader and the grate, in which case a dedicated cap ring can be provided, so as to reliably close the distribution chamber of the flame spreader. The cap ring can be made of a different material than the materials that are used for the flame spreader and/or the grate which allows using alternative manufacturing techniques that may provide for improved performance, such as better coupling of parts and/or higher precision in dimensional control of the parts.

The flame spreader can be attached to the grate by a plurality of clamps or bolts, so that the upper part comprising the at least one foot, the grate and the annular flame spreader, is reliably combined into an integral unit that can be handled as a single piece

In order not to impede the gas flow through the annular spreader, the flame spreader can comprise a plurality of lugs that extend outside of the annular shape of the flame spreader and which are located below bars of the grate, wherein bolts extend through the lugs into the bars.

To provide for a connection between gas outlet and gas inlet, and at the same time to provide for means for facilitating the placement of the upper part with respect to the base part, the gas inlet can comprise a duct protruding downwards from the upper part, and the gas outlet of the base part can comprise a receptacle for insertion of said duct. When installing the upper part on the base part, the upper part is placed above the base part in a manner so that the protruding duct is oriented to coincide with the receptacle of the base part, whereupon the upper part is lowered to thus insert the duct into the receptacle.

In preferred embodiments, the gas outlet of the base part protrudes upwards from the base part, so that the upper edge of the gas outlet is located above the cooktop surface. When the device is to be cleaned with the upper part having been removed from the base part, the cooktop surface with the base part thus can be safely wetted with cleaning liquid without risk of water flowing into the gas outlet. Providing for a raised configuration of the gas outlet further can facilitate aligning the upper part with respect to the base part, since thus both the duct of the upper part and the corresponding receptacle of the base part can be easily haptically located and thus serve as locator elements that facilitate the alignment.

The duct and the receptacle can be shaped to allow insertion of the duct into the receptacle only at a predetermined orientation of the upper part with respect to the base part. The duct and the receptacle thus not only act as locator elements, but also ensure proper angular orientation of the upper part with respect to the base part. It should be understood that in such embodiments the predetermined orientation needs not be a single orientation, but also may comprises a plurality of orientations, such as an orthogonal pattern of orientations in which the upper part, starting from a first orientation, selectively can be located turned by 90°, by 180° or by 270°.

In such embodiments the duct and the receptacle can have a cross-sectional shape which has a single axis of symmetry, so as to allow insertion of the duct into the receptacle only at two predetermined orientations of the upper part with respect to the base part, so that the upper part selectively can be set onto the base part in a first orientation and in a second orientation in which the upper part is rotated by 180° with respect to the first orientation.

Restricting the orientation of the upper part to a first orientation and to a second orientation in which the upper part is rotated by 180° with respect to the first orientation has the advantage that in such embodiments the duct and the receptacle can be given a lengthy shape, such as a an oblong shape or a generally rectangular shape, optionally with rounded corners, in which the longer axis extends tangentially to the annular shape of the flame spreader which allows for a substantially larger cross-section, and hence flow area, of the gas supply duct, as if the duct and the receptacle have a, for example, circular shape. Furthermore, the duct can have a shape that itself influences the flow characteristics of the fuel gas-air mixture as it is passed via the duct to the distribution chamber of the flame spreader, such as selecting a shape for the interior wall of the duct which provides for a Venturi effect on the gas air mixture as it passes through the duct. Thus, the duct can have a shape which provides for a constriction or throat along the length of the duct, so that the fuel gas-air mixture is accelerated when passing the duct.

The base part further can comprise an adjustable Venturi assembly for control of the flow of air that is used in the mixture of fuel gas and air which is fed via the distribution chamber to the plurality of gas outlet openings. In order to allow installation of the burner assembly in a kitchen bench without any parts protruding beyond the thickness of the bench, the adjustable Venturi assembly preferably is configured for horizontal installation. The adjustable Venturi assembly can be designed to draw in primary air from the ambient of the burner assembly under the cooktop surface. Upon mixing such air with fuel gas that is supplied from a gas supply, the fuel gas-air mixture flows upwards through the vertical inlet duct into the distribution chamber of the flame-spreader.

To shut off the gas flow to the gas cooking assembly in case that the burner flame extinguishes, such as by an unintended interruption of the gas supply, a strong air flow, or liquid spilling over the burner assembly, the base part further may comprise a thermocouple for providing a flame signal indicating that the burner flame is ignited, and a safety valve for shutting off the gas supply if the thermocouple no longer provides the flame signal. In such embodiments the thermocouple senses the temperature near the burner nozzle. If it is determined that the temperature has fallen below a preset minimum temperature, it is assumed that the burner flame no longer is burning and hence the gas supply is shut off by the safety valve.

The gas cooking assembly of the present invention can be used in a hob in combination with at least one further gas burner which either may be a conventional fixed gas burner or another gas cooking assembly of the present invention, so that by changing the orientation of the gas cooking assembly of the present invention the distance between the at least two gas burners can be varied, such as to selectively provide for two individual cooking zone, or to provide for one combined cooking zone for heating larger lengthy cooking vessels.

Thus, a hob may comprise two gas burners, on which at least one is a gas cooking assembly as suggested herein, which is located such that the gas inlet is located at a distance to the second burner so that the grates of the two gas burners selectively can be placed adjacent to each other to form a combined cooking zone, or the upper part of the inventive gas cooking assembly can be turned by 180° so that its grate is located at a larger distance to the second burner. When drawing a line through the centers of the burners, the gas inlet of the rotatable burner assembly thus would be placed on such line facing away from the second gas burner.

Similarly, in a hob having three gas cooking zones, the burners may be arranged to be located along a line passing through the centers of the burners, wherein the middle one can be located such that the gas inlet is located 90° above or below the connection line, so that by rotating the middle burner, the burner can be placed so as to form a triangle. Further, one or two of the burners to the left and to the right can be oriented such that the gas inlet is located on the said connection line at a distance that such burner selectively can be placed proximal to the middle burner, so as to form a combined cooking zone.

