Gas burner, a cooking hob, and a gas cooking appliance

Abstract

A gas burner (1) for a gas cooking appliance (100), comprises: a connection device (53) configured to receive a combustible gas from a gas supply source; an injector device (34) positioned downstream of the connection device (53), the injector device (34) comprising at least one gas inlet for receiving the combustible gas from the connection device (53), at least one primary air inlet (13), and a mixing section (56) configured to mix the combustible gas and the primary air to a gas mixture; a burner head (23) positioned downstream of the injector device (34), the burner head (23) comprising a plurality of flame ports (31) and a distribution chamber (57) for distributing the gas mixture to the flame ports (31); and means (8, 18, 9) for guiding an airflow through at least one airflow region (50) for cooling at least one of the connection device (53), the injector device (34) and / or the burner head (23), wherein the airflow is different to a flow of primary air and combustible gas.

Description

[0001] 202401327

[0002] Gas burner, a cooking hob, and a gas cooking appliance

[0003] The present invention relates to a gas burner, a cooking hob, and a gas cooking appliance, for instance a gas hob. More specifically, this invention pertains to a gas burner that may be utilized with hydrogen as a combustible gas. Hydrogen, being a clean and efficient fuel, may offer advantages, for instance in terms of reducing carbon emissions or enhancing energy efficiency.

[0004] If the combustible gas is hydrogen, the unique physical and chemical properties of hydrogen need to be considered. Hydrogen, with an atomic number of 1, is the lightest and most abundant element. It exists predominantly as a diatomic molecule (H2) under standard conditions. Hydrogen gas is colorless, odorless, and highly flammable, with a wide flammability range of 4% to 75% in air. Its low molecular weight results in a high diffusivity.

[0005] Hydrogen combustion may produce nitrogen oxides (NOX), which are harmful pollutants. Although hydrogen combustion primarily produces water vapor as a byproduct, the high temperatures involved can cause nitrogen in the air to react with oxygen, forming NOX. Therefore, while the primary byproduct is water vapor, the formation of NOXshould be mitigated to avoid adverse environmental and health effects.

[0006] Despite these challenges, the potential benefits, for instance with respect to ecological effects, of hydrogen burners are significant.

[0007] It is one object of the present invention to provide an improved gas burner, e.g., for household appliances.

[0008] Therefore, a gas burner to burn a combustible gas for a gas cooking device is provided. According to an aspect, a gas burner for a gas cooking device comprises a connection device configured to receive a combustible gas from an external gas supply source. The gas burner further comprises an injector device positioned downstream of the connection device. The injector device comprises at least one gas inlet for receiving the combustible gas from the connection device, at least one primary air inlet, and a mixing section 202401327 configured to mix the combustible gas and the primary air to a gas mixture. The gas burner further comprises a burner head positioned downstream of the injector device. The burner head comprises a plurality of lateral flame ports and a distribution chamber for distributing the gas mixture to the flame ports. The gas burner further comprises means for guiding an airflow through at least one airflow region for cooling at least one of the connection device, the injector device and / or the burner head while the combustible gas is burned, wherein the airflow is different to a flow of primary air and combustible gas.

[0009] The guided airflow allows to carry away excess heat from the das burner thereby cooling the structural elements of the burner under operation. Using hydrogen as combustible gas, may lead to higher temperatures as with hydrocarbon-gas based burners.

[0010] According to an embodiment, the at least one primary air inlet may be interpreted as a plurality of primary air channels.

[0011] According to an embodiment, the connection device comprises a gas coupling piece configured to be connected to the gas supply source, and wherein the burner head comprises a central axis that is perpendicular to its top surface and passes through its geometric center, wherein the distance between the gas coupling piece and the central axis is at least 40 mm.

[0012] According to an embodiment, the distance between the gas coupling piece and the central axis is at least 45 mm, preferably at least 48 mm, more preferably at least 49 mm, more preferably at least 50 mm. Having a sufficient distance may protect the gas coupling piece from too high heat during operation and may thereby prevent deformations over time and may thereby prevent gas leaks.

[0013] The distance, is for example, measured with the point of the coupling piece being furthest away from the central axis of the burner head.

[0014] In embodiments, the means to guide the airflow through the at least one airflow region are configured such that the airflow region extends axially along the connection device. 202401327

[0015] According to an embodiment, the airflow region extends longitudinally, e.g., in an axial direction.

[0016] According to an embodiment, the injector device comprises an upper part and a lower part that is connected to the upper part through a jet injector configured to guide the combustible gas from the lower part to the upper part. The connection device comprises an injector holder for holding the lower part of the injector device. The injector holder is configured to receive the combustible gas from the gas coupling piece and to guide it to the lower part of the injector device. The injector holder comprises wings extending radially from a central axis as means to guide an airflow through the at least one airflow region. The wings at least partially enclose the airflow region.

[0017] In embodiments, the means for guiding an airflow give rise to a heat transfer from the burner to the environment. Air may flow from above the cooktop through an hob plate towards the coupling piece.

[0018] The wings may increase the surface area exposed to the airflow, which may improve heat dissipation. This could be advantageous for cooling at least some of the components of the gas burner, as an increased surface area might allow for more effective heat transfer.

[0019] The wings may include openings or channels, which may ensure a streamlined airflow. This may enhance a cooling effect and minimize turbulence, which may support an efficient operation.

[0020] The wings may act as conduits for heat generated by other parts of the device. By channeling this heat into the wings, it may be effectively transferred to the passing airflow, thereby potentially reducing operating temperatures and preventing overheating.

[0021] The wings may comprise specific materials that have high thermal conductivity, thereby enhancing their ability to dissipate heat. The overall structure may be configured to balance strength and thermal performance thereby ensuring that the device remains robust while effectively managing heat. 202401327

[0022] The wings may contribute to the longevity and reliability of the device. By maintaining lower operating temperatures, the risk of thermal damage to sensitive components may be reduced, potentially extending the lifespan of the device.

[0023] In embodiments, the wings may be arranged in a cloverleaf pattern.

[0024] In embodiments, the injector holder comprises only one, two, three or four wings.

[0025] According to an embodiment, the injector device is threaded to the injector holder.

[0026] According to an embodiment, the upper part of the injector device comprises two heads, one cylindrical head followed by (in downstream direction) a hexagonal head. The hexagonal head may allow to tighten the threaded connection between the injector device and the injector holder sufficiently. This may be advantageous because hydrogen has a high diffusivity and may easily escape if the threading is not sufficiently tight.

[0027] According to an embodiment, the height of the cylindrical head along the injection direction may be in the range between 3.5 mm - 6 mm and the respective height of the hexagonal head may be between 5 mm - 10 mm.

[0028] According to an embodiment, the injector holder comprises one, two or three wings, wherein the wings may transfer heat from the bulk of the injector holder towards the environment, e.g. through passing air.

[0029] According to an embodiment, at least one wing comprises at least one opening through which the airflow extends.

[0030] According to an embodiment, at least one of the at least opening of the at least one wing has a triangular or quadrilateral shape.

[0031] According to an embodiment at least one of the wings has an opening through which an ignition device may extend. 202401327

[0032] According to an embodiment, the gas burner comprises an ignition and / or safety system, in particular a spark plug and / or a thermocouple. The spark plug may be configured to ignite the combustible gas-air mixture. In embodiments, the thermocouple is connected to a magnet group to shut down the combustible gas in the case that the flame extinguishes unexpectedly.

[0033] According to an embodiment, the combustible gas contains hydrogen, preferably more than 80% by volume, more preferably more than 95% by volume, more preferably pure hydrogen.

[0034] The term “pure hydrogen” refers to hydrogen with a high degree of purity. It is understood that even gases referred to as “pure” may contain trace amounts of impurities due to limitations in purification processes. Therefore, “pure hydrogen” is intended to include hydrogen with a purity level of at least 97 %, 98%, 99%, 99.5%, 99.9%, 99.99%, 99.999%, or higher.

[0035] One potentially beneficial aspect of using hydrogen as a combustible gas is the elimination of CO2 emissions during combustion. Hydrogen combustion produces only water vapor as a primary byproduct, making it an attractive option for reducing greenhouse gas emissions and combating climate change.

[0036] Hydrogen also has a high energy content per unit mass, which may result in efficient and high-temperature combustion, making it suitable for applications requiring intense heat, such as cooking. This may be beneficial for cooking dishes that require sudden high heat followed by quick decrease of the heat. This capability is particularly useful for techniques like stir-frying, where one needs to sear ingredients at very high temperatures and then reduce the heat swiftly to avoid overcooking.

[0037] The rapid diffusivity of hydrogen, while posing containment challenges, also means that any leaked hydrogen may disperse quickly, reducing the risk of accumulation and subsequent explosion. 202401327

[0038] Hydrogen may be produced from a variety of renewable sources, such as water electrolysis using solar or wind power, aligning with broader goals of sustainability and energy independence.

[0039] The use of pure hydrogen burners might significantly reduce the environmental impact of cooking. By eliminating CO2 emissions, hydrogen burners may contribute to the reduction of the overall carbon footprint of households. This is particularly important in regions where cooking with biomass or fossil fuels is prevalent, as it may lead to substantial improvements in air quality and public health.

[0040] The pre-aeration, that may be considered as the mixing of combustible gas and primary air in the mixing section, may reduce NOXemissions that may occur during combustion of combustible gases comprising hydrogen.

[0041] According to an embodiment, the gas burner comprises a heat shield radially extending from a central axis of the gas burner and positioned between the connection device and the burner head.

[0042] According to an embodiment, the heat shield may be constructed from materials that possess high thermal resistance and reflectivity. Suitable materials may include stainless steel, which may offer high heat resistance and durability, or aluminum, which may provide good reflectivity and is lightweight or even in brass, which is commonly used. In embodiments, ceramic materials may be used due to their high thermal insulation properties.

[0043] According to an embodiment, the heat shield comprises openings through which the at least one airflow region extends. The openings may connect an area above a hob plate to an area below the hob plate. In embodiments, the heat shield rests in an aperture of the hob plate and / or on an edge of the aperture.

[0044] The term “opening” is considered to also include indentations, clearances, recesses, notches, and cutouts. 202401327

[0045] According to an embodiment, at least one of the openings of the heat shield may be axially aligned with an opening of one of the wings. This may allow for a cylindrical airflow region extending in axial direction.

[0046] According to an embodiment, the openings of the wings and the openings of the heat shield are shaped and aligned such that during operation of the gas burner an airstream may pass first through at least one opening of the heat shield and then through at least one opening of at least one wing.

[0047] An airstream may occur due to temperature differences during operation. However, one may also contemplate that the cooling air is conveyed along the airflow region, e.g., using a fan.

[0048] According to an embodiment, the heat shield comprises three openings.

[0049] According to an embodiment, the heat shield has a geometry that holds the burner head in a fixed position by means of an asymmetry, for instance in form of an opening of the heat shield and a corresponding protrusion of the burner cap preventing rotation.

[0050] According to an embodiment, the gas burner comprises at least one gasket positioned downstream of the injector holder. The at least one gasket comprises openings through which the at least one airflow region extends, and wherein the at least one gasket is at least partially made of heat resistant materials. In embodiments, the gasket is arranged between the wings and the heat shield. The gasket and the wings of the injector holder may have a same or similar shape.

[0051] According to an embodiment, the heat-resistant materials may comprise mica. Mica offers several potentially beneficial properties, including high thermal resistance and chemical stability. These characteristics make mica suitable for high-temperature applications, providing reliable performance and durability.

[0052] Mica can be a naturally occurring mineral that is based on a collection of silicate minerals and comprises varying amounts of potassium, iron, aluminum, magnesium, and water.

[0053] Mica products may resist chemicals, acids, gases, alkalis, and oils. Mica gaskets can be 202401327 implemented highly fireproof, incombustible, non-flammable, infusible. In embodiments, mica gaskets resist temperatures above 1.000 C°.

[0054] According to one embodiment, the heat-resistant materials may comprise graphite. Graphite provides potentially beneficial properties such as good sealing capabilities, especially at high temperatures, and good thermal conductivity, which aids in heat dissipation. Additionally, graphite gaskets are flexible and may conform to irregular surfaces, ensuring a tight seal.

[0055] According to one embodiment, the heat-resistant materials may comprise vermiculitebased, such as Thermic lite. Vermiculite-based materials can withstand very high temperatures and are resistant to a wide range of chemicals. They offer long-term reliability and maintain their sealing properties over extended periods of time.

[0056] According to one embodiment, the heat-resistant materials may comprise ceramic fiber. Ceramic fiber can withstand very high temperatures. It is lightweight and chemically stable, in particular resistant to many corrosive substances.

[0057] According to an embodiment, the at least one gasket is configured to allow air pass through, in particular not blocking an air flow through the airflow region.

[0058] According to another aspect, a gas burner comprises an injector device that comprises at least one gas inlet for receiving combustible gas, a mixing section and a jet injector. The mixing section is communicatively coupled to the jet injector and comprises a plurality of primary air channels for receiving primary air. The jet injector has an injection direction, the primary air channels have respective channel directions, and the channel directions may extend in an oblique direction with respect to the injection direction.

[0059] A direction can be considered oblique with respect to a reference direction if it is neither parallel, nor antiparallel nor perpendicular to the reference direction. One may also refer to a direction being inclined with respect to a reference direction.

[0060] According to an embodiment, the gas burner comprises a connection device configured to receive a combustible gas from a gas supply source. The gas supply source may be an 202401327 external gas supply source. For example, the gas supply source can be a port, gas cylinder or the like.

[0061] The connection device may include a threaded coupling that can be attached to a gas supply hose, ensuring a tight seal to prevent gas leaks during operation.

[0062] According to an embodiment, the connection device may comprise a quick-connect fitting that allows for easy attachment and detachment from the gas supply source. This quickconnect fitting may be designed to interface with typical gas supply connectors, facilitating rapid setup and removal, which may be useful in portable or temporary installations.

[0063] According to an embodiment, the injector device is positioned downstream of the connection device.

[0064] Downstream is considered to be a direction of a flow of combustible gas from the gas supply source towards a point of use. Upstream refers to an opposite direction. The gas burner ports or flames may be considered the point of use.

[0065] According to an embodiment, a burner head is positioned downstream of the injector device, the burner head comprising a plurality of flame ports configured to release the gas mixture. The gas mixture includes combustible gas, e.g., hydrogen, and ambient air introduced into the mixture as primary air. The gas mixture may burn from flame ports and can be inflamed, e.g., by an ignition device.

[0066] According to an embodiment, the burner head comprises a distribution chamber for distributing the gas mixture to flame ports. Flame ports can be formed by a burner cap placed on the burner head and specific contours at the interface between the cap and the head.

[0067] According to an embodiment, the distribution chamber is delimited by a burner cap positioned on the burner head.

[0068] According to an embodiment, the injection direction is colinear with a main axis of the injector device. 202401327

[0069] According to an embodiment, the injector device injection direction deviates from a main axis of the burner device due to a turn before the gas is injected. This turn may redirect the injection flow, allowing it to exit at a different angle, for instance turned by 90 degrees relative to the main axis. This may be beneficial for fitting the components into limited spaces.

[0070] According to an embodiment, the injection direction and the channel directions enclose angles between 60° and 100°.

[0071] In embodiments, the angles enclosed by the injection direction and the channel directions may be between 60° and 85°, preferably between 60° and 80°, more preferably between 65° and 75° more preferably between 67° and 73°, more preferably between 69° and 71°, more preferably 70°.

[0072] An inclination of the primary air channel not normal to the main axis of a jet injector may favor turbulences within a downstream Venturi tube and improve the homogeneity of the combustible gas-air mixture. The inclination may also reduce a risk of combustible gas exiting into the environment if a relatively low mass or volume flow is set.

[0073] In embodiments, all angles enclosed by the injection direction and the channel directions have the same size. This may help to avoid that amounts of hydrogen escape through the primary air channels.

[0074] According to an embodiment, a straight line along the injection directions and lines along the channel directions all meet at one converging point. If the angles enclosed by the injection direction and the channel directions are in the range between 1° and 89°, then this (hypothetical) point is downstream compared to that point on the line along the injection direction that has the axial height of the channel entries.

[0075] Angles mentioned herein are intended to include slight deviations, typically within a tolerance range, for instance a tolerance range of 10 degrees, 5 degrees, 2 degrees, 1 degree, 0.5 degrees, 0.2 degrees or 0.1 degrees, unless otherwise specified. 202401327

[0076] Respectively, terms like “parallel” and “perpendicular” are to be understood as including slight deviations within these tolerance ranges.

[0077] Absolute quantities like distances mentioned herein are intended to include slight deviations, for instance a relative tolerance range of 30%, 20%, 10%, 5%, 2% or 1% unless otherwise specified.

[0078] According to an embodiment, the number of primary air channels is between 8 and 12.

[0079] According to embodiments, the number of primary air channels is between 4 and 16, preferably between 6 and 14, preferably 8, 9, 10, 11 , or 12.

[0080] According to an embodiment, the primary air channels are distributed equidistantly circumferentially along the mixing section. An equidistant distribution may lead to a homogenous primary air intake thereby improving combustion quality and safety.

[0081] According to an embodiment, primary air channels are considered equidistant if the distance between each pair of neighboring channels is identical. This includes slight deviations of the distances within a tolerance range of 10%, 5%, 2% or 1%.

[0082] According to an embodiment, the air channels have elliptical cross-sections.

[0083] According to an embodiment, the air channels have circular cross-sections.

[0084] According to an embodiment, the primary air channels have cross-sectional diameters in the range between 0.8 mm and 1.2 mm.

[0085] According to an embodiment, the primary air channels have cross-sectional diameters in the range between 0.9 mm and 1.1 mm, preferably between 0.95 mm and 1.05 mm, more preferably 1 mm.

[0086] According to an embodiment, the gas burner comprises a burner head positioned downstream of the injector device. The burner head comprises a plurality of flame ports. The gas burner further comprises a burner cap positioned on the burner head, thereby 202401327 forming a distribution chamber between the burner head and the burner cap. The burner cap extends radially beyond all flame ports.

[0087] According to an embodiment, the flame ports are positioned laterally on the burner head, and the burner cap is disk-shaped and protrudes radially beyond the burner head by 3.5 mm to 6.5 mm.

[0088] According to an embodiment, a protruding portion of the burner cap is at least partially curved or angled (along a radial direction), for instance downward curved (axially). Such a geometry may help to stabilize the flame. One may contemplate of a protruding wing at the lateral edge of the burner cap.

[0089] According to an embodiment, the burner cap is disk-shaped.

[0090] According to an embodiment, the diameter of the burner cap is in the range between 60 mm and 90 mm, preferably, between 68 mm and 88 mm.

[0091] The pre-aeration may support the development of a shorter flame during the combustion of gases comprising hydrogen, which favors the use of pans of different diameters on the same burner.

[0092] According to an embodiment, the injector device comprises an upper part and a lower part that is communicatively coupled to the upper part through the jet injector. The upper part has an internal cup-shaped geometry and comprises a circumferential lateral side and a bottom side. The burner head comprises a Venturi tube. The Venturi tube comprising an inlet for receiving the gas mixture from the mixing section, an outlet for releasing the gas mixture to the distribution chamber, a converging section with decreasing diameter downstream of the inlet, a throat section with a constant diameter downstream of the converging section, and a diverging section with increasing diameter downstream of the throat section and upstream of the outlet. The Venturi tube reaches into the upper part of the injector device, thereby forming the mixing section enclosed between the lateral side of the upper part, the bottom side of the upper part and the inlet of the Venturi tube. 202401327

[0093] A Venturi tube may operate based on fluid dynamics principles to efficiently draw combustible gas and primary air into the tube and allow for a homogenous mixture. Initially, the gas mixture may enter the Venturi tube and flow through the converging section, where the cross-sectional area decreases. This reduction in area may increase the velocity of the mixture and decrease its pressure.

[0094] At the narrowest part of the tube, the throat section, the mixture may reach its maximum velocity and minimum pressure. This low pressure at the throat may maintain the suction effect that draws in combustible gas and primary air.

[0095] After passing through the throat, the hydrogen-air mixture may enter the diverging section, where the cross-sectional area increases. This may cause the velocity to decrease and the pressure to increase, allowing for a mixed combustible gas-air flow for combustion.

[0096] The pre-mixture of hydrogen and primary air may take place in the mixing section and in the Venturi tube. According to an embodiment, the resulting mixture has a lambda value between 6% and 20%, preferably between 8% and 12%, more preferably between 10 % and 12 %.

[0097] The lambda value for a hydrogen burner is considered to be the ratio of the actual amount of air supplied to the theoretically required amount of air for complete combustion. A lambda value of 1 indicates a stoichiometric mixture, where there is exactly that amount of air for the complete combustion of hydrogen. Values below 1 indicate a richer mixture (less air), while values above 1 indicate a leaner mixture (more air).

[0098] A sufficiently large lambda value, for instance at least 8 %, may avoid a too low aeration that might cause too low velocity and pressure values at the flame ports. Thereby too high temperatures and the corresponding risk of leaks may be avoided, also NOXemissions may be reduced. On the other hand, a sufficiently small lambda value, e.g., at most 12 %, may help to avoid flashback.

[0099] A flashback may occur if the flame propagates back into the burner, e.g., into the distribution chamber, moving upstream against the flow of the gas-air mixture. This may 202401327 occur when the flame speed exceeds the flow velocity of the unburned gas mixture, causing the flame to travel back through the flame ports.

[0100] According to an embodiment, the inner diameter of the throat section of the Venturi tube is in the range between 2.5 mm and 3 mm.

[0101] This geometry of the Venturi tube may support dragging the proper quantity of primary air and to avoid hydrogen recirculation, particularly when the burner is working on low power rates.

[0102] According to an embodiment, the distance between the inlet of the of the Venturi tube and the jet injector is between 1.8 mm and 4.5 mm.

[0103] The distance between the inlet of the of the Venturi tube and the jet injector is considered to be the distance between a point of the jet injector where the combustible gas is released from the jet injector into the mixing section and the inlet of the Venturi tube.

[0104] The suggested distances may prevent unburnt hydrogen and optimize the primary air entrainment.

[0105] According to an embodiment, the flame ports of the burner head may be designed as slits. The slits may vary in length and width to control the size and intensity of the flame.

[0106] According to an embodiment, the slits may be positioned laterally on the burner head.

[0107] According to an embodiment, the flame ports may be designed as slits with a rectangular cross-section.

[0108] The term “rectangular” as used herein also encompasses shapes that are substantially rectangular, including those with slightly rounded corners or minor deviations from perfect right angles. For instance, minor deviations may include angles that differ by up to 10 degrees from a perfect right angle. 202401327

[0109] According to an embodiment, the flame ports may be designed as slits with a triangular cross-section.

[0110] The term “triangular” as used herein also includes shapes that are substantially triangular, such as those with slightly curved sides or minor deviations

[0111] According to an embodiment, the flame ports may be designed as slits with a tapered cross-section. In this design, the width of the slit decreases from the outer surface towards the inner surface of the burner head. This tapering may help in directing the flame more accurately.

[0112] The term “tapered” as used herein refers to shapes where the width decreases progressively from one end to the other. This includes shapes that are not perfectly linear but maintain a general tapering form. For instance, minor deviations may include a tapering angle that varies by up to 10 degrees along the length of the taper.

[0113] According to an embodiment, the flame ports may be elliptical, e.g., circular, in shape.

[0114] According to an embodiment, the flame ports may be uniformly distributed around the burner head.

[0115] According to another embodiment, the flame ports may include a combination of different shapes, such as rectangular, triangular, and circular.

[0116] The term “elliptical” as used herein also encompasses shapes that are substantially elliptical.

[0117] According to an embodiment, at least one of the flame ports is a slit that comprises sides with a height (H) and a bottom with a width (W), wherein the height (H) is between 1 mm and 1.2 mm, and wherein the width (W) is between 0.6 mm and 1 mm.

[0118] According to an embodiment, the at least one slit has a rectangular cross-section. 202401327

[0119] The described height H and width W yields significantly smaller slits than used for conventional hydrocarbon gas burners. This may be particularly beneficial when the combustible gas is hydrogen due to the low quenching distance of hydrogen.

[0120] According to an embodiment, the number and cross-section of the flame ports is configured such that the power ratio of the burner during operation is in the range 80 - 110 W / mm2. The power ratio is the quotient of the power output of the burner and the surface area of the top side of the burner head. The power output of the burner is the product of the mass flow rate of the gas mixture and its calorific value.

[0121] The power ratio of the burner during operation is in the range 80 - 110 W / mm2may support the flame stability.

[0122] Furthermore, a cooking hob is provided. The cooking hob comprises a gas burner according to any one of the described embodiments.

[0123] The terms cooking hob, gas hob and hob may be used interchangeably in this context.

[0124] Furthermore, a gas cooking appliance is provided. The gas cooking appliance comprises a gas burner according to any one of the described aspects or embodiments and / or a cooking hob according to an embodiment described above.

[0125] According to one embodiment, the gas cooking appliance is a gas stove, in particular for combusting hydrogen. A gas stove may feature a cooktop with gas burners, hob plate and may include an oven underneath.

[0126] 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.

[0127] 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: 202401327

[0128] Figure 1 shows a perspective schematic view of a gas cooking appliance.

[0129] Figure 2 shows an expanded view along its central axis of an embodiment of a gas burner.

[0130] Figure 3 shows a perspective schematic view of a connection device for the gas burner of Fig. 2.

[0131] Figure 4 shows a top view of a connection device for the gas burner of Fig. 2.

[0132] Figure 5 shows a perspective view of an injector device for the gas burner of Fig. 2.

[0133] Figure 6 shows a cross-sectional view of the injector device of Fig. 4 with an inserted Venturi tube.

[0134] Figure 7 shows a cross-sectional view of the assembled gas burner of Fig. 2 and detailed views of aspects of the burner cap and the injector device and part of the Venturi tube.

[0135] Figure 8 shows a cross-sectional view of the burner head of the gas burner of Fig. 2.

[0136] Figure 9 shows a side view of the burner head of Fig. 8 and details of one flame port.

[0137] In the Figures, like reference numerals designate like or functionally equivalent elements, unless otherwise indicated.

[0138] Although the present invention has been described in accordance with preferred embodiments, it is obvious for the person skilled in the art that modifications are possible in all embodiments.

[0139] Figure 1 shows a perspective schematic view of a gas cooking appliance 100. The cooking appliance 100 is a gas hob and has a cooking or covering plate 101, on which there are four cooking hobs 104 are placed. An appliance housing 102 covers the bottom of the gas hob 100. At the right corner, a gas port 103 projects, into which gas flows in 202401327 coming from the external gas network. Internally, not shown, a manifold distributes the incoming gas, e.g., hydrogen, to the respective burner 1. Each cooking hob 104 comprises a gas burner 1 with its corresponding burner cap 25. The gas cooking appliance 100 comprises control knobs 48 for controlling the appliance.

[0140] The disclosed gas hob 100 and gas burners 1 are adapted to burn hydrogen in a reliable manner. Burning hydrogen may pose specific requirements, e.g., heat transfer, flow properties, mixture of the combustible gas and air, leakage integrity. Some of which are addressed by the aspects and embodiments shown in the following.

[0141] Figs. 2 - 9 show an embodiment of a gas burner 1 and its elements. The gas burner of Figure 2 may be used as one of the gas burners of the gas cooking appliance depicted in Figure 1.

[0142] The gas burner 1 is a hydrogen burner, and comprises, from top to bottom in the orientation of Fig. 2, a burner cap 25, a burner head 23, a heat shield 27, and a connection device 53. The burner 1 has a central axis 43 which reaches through a hop plate 2 (see Fig. 7) with an aperture when installed. A circular gasket 26 supports the heat shield 27 on the edge of the aperture, and a second gasket 11 is placed between the upper part of the connection device 53 and the shield 27.

[0143] When operated, hydrogen as combustible gas runs from a gas coupling piece 15 of the connection device 53 through a pipe 3 into an injector 34 held in an injector holder 9 of the connection device 53. A gas mixture is generated and fed through a Venturi tube 47 of the burner head 23.

[0144] The connection device 53 comprises the injector holder 9. The connection device 53 is depicted in detail in Figures 3 and 4. The injector holder 9 comprises three wings 4 which comprise openings 8. The wings 4 extend radially from the central axis 43, and the openings 8 are configured to enable an airstream for cooling purposes through an airflow region 50 through these openings 8. From the lower part, below the wings, of the injector holder 9 a gas pipe 3 extends radially with respect to the primary axis 43 of the burner 1. The gas pipe 3 terminates in a gas coupling piece 15. The gas coupling piece 15 may couple to a gas supply through a hydrogen tight fit and receives the hydrogen to be burnt. 202401327

[0145] The coupling piece 15 is, for example, coupled to a hose, internal pipe of the gas hob or another coupling means. The distance 60 between the gas coupling piece 15 and the primary axis 43 of the burner 1 is approximately 50 mm. Due to the distance of the coupling piece 15 to the center of the burner 1 heat generated during operation may dissipate sufficiently, so that a coupled gas supply is not damaged or subjected to excessive thermal stress.

[0146] An injector device 34 is positioned in the injector holder 9. The injector device 34 comprises a jet injector configured to release a combustible gas, for instance hydrogen. The injector device further comprises an upper part 6 comprising two heads 61 and 10, which can be better seen in Fig. 7. The first head 61 is cylindrical. The second head 10 is hexagonal. They extend above (with respect to the orientation of Figure 2) the injector holder 9 along the main axis 43 of the burner 1, wherein the cylindrical head 61 is positioned anterior to the hexagonal head 10 and wherein both heads 61, 10 are coaxially aligned, and wherein the height of the hexagonal head is greater than the height of the cylindrical head 61. Figs. 5 and 6 show the injector device 34 in detail.

[0147] The cylindrical head 61 comprises a plurality of primary air channels 13 configured to regulate the primary air entrainment. The primary air channels 13 are inclined by 20 degrees with respect to the horizontal with regard to the orientation of the figure. The primary air channels 13 are all positioned at the same height. The primary air channels 13 are uniformly distributed around the lateral surface area of the cylindrical head 61.

[0148] The hexagonal head 10 is positioned above (with regard to the orientation of the figure) the cylindrical head 61. The hexagonal head 10 is configured to be securely tightened by an appropriate tool, particularly having a sufficient height for this purpose. This tightening is sufficiently strong to ensure that no or only marginal amounts of hydrogen may escape.

[0149] Gaskets 11 , 26 are positioned on the injector holder 9 (Fig. 2). The gaskets 11 , 26 are fabricated from high-temperature resistant materials, for instance mica. They are configured such that they do not cover the openings 8 of the wings 4 of the injector holder 9 so that they do not hinder an air flow through these openings 8. The air flow may help to cool the components during use of the burner. 202401327

[0150] The heat shield 27 is positioned above the hexagonal head 10 and the gaskets 11 , 26 and below the top part of the burner head 23. The heat shield 27 is disk-shaped and comprises a central opening 19 through which the Venturi tube 47 may extend. The heat shield 27 is configured to absorb the flame heat and to decrease the temperature of the other components below. The heat shield 27 has three openings 18 to allow air circulation that may decrease temperatures in other components of the burner. The geometry of the heat shield 27 is configured such that a burner head 23 can be positioned on it in a fixed position. In particular, the burner head 23 cannot be rotated with respect to the primary axis 43 of the burner 1.

[0151] The burner head 23 functions as a base on which a cap 25 rests, and it functions also as a spreader in the following sense: The burner head 23 comprises a pipe 30 that fits into the central opening 19 of the heat shield 27 and acts as a Venturi tube. The pipe 30 is part of the burner head 23, but can alternatively be a separate piece connected to the injector device 34 in a hydrogen-impermeable manner and the top part of the head, ensuring that the gas mixture flows through while maintaining a tight seal to prevent any gas leakage. The burner head 23 thus comprises a Venturi tube 47 (see Figure 8) configured to enable mixing of the primary air with the combustible gas to a mixture.

[0152] The burner cap 25 is positioned on the burner head 23. The cap 25 comprises a wing 38 to favor flame stabilization. The cap has a protrusion 24 that fits into a corresponding opening 28 of the burner head 23, thereby preventing the cap 25 from rotation about the primary axis 43 of the burner.

[0153] A distribution chamber 57 is formed between the burner head 23 and the burner cap 25. The gas burner 1 of the embodiment also comprises an ignition system 12 comprising an ignition device, for instance a spark plug 64 and a thermocouple 63, the spark plug 64 being configured to produce a spark for igniting the gas-air mixture that exits flame ports 31 of the burner head 23. The ignition system extends through openings 14, 17 of the gasket 9 and through openings 7, 29 of a wing 4 of the injector holder 9 and through openings 20, 21 of the heat shield 27.

[0154] Figure 5 shows a perspective view of the injector device 34. The injector device 34 comprises a pipe 35 in the lower part 58 and comprises a second threading 36 which is 202401327 configured to engage with a first threading of an injector holder 9 (not depicted in Figure 3). The injector device 34 comprises a cylindrical head 61 which comprises the primary air channels 13 that are inclined by 20 degrees with respect to a plane orthogonal to the primary axis 43 of the cylindrical head 61 as explained above. In other words, the primary air channels are inclined by 70 degrees with respect to the primary axis 43 of the cylindrical head 61. The cylindrical head 61 is connected to a hexagonal head 10. The connection is hydrogen-impermeable.

[0155] Figure 6 shows a cross-sectional view of the injector device 34. The jet injector 37 is positioned between the upper part 6 and the lower part 58 and comprises an injection direction 62. In this embodiment, the injection direction is colinear with the main axis 62 of the injector device 34. The jet injector outlet 39 is positioned inside the cylindrical head 61.

[0156] The interior of the upper part 6 has a cup-shaped geometry with a lateral side or sidewall 66 and a bottom side 67.

[0157] The cylindrical head 61 comprises the primary air channels 13 reaching from the outside into the interior through the lateral side wall of the injector device 34 with channel directions 49. The size of the angles a between the injection direction 62 and the channel directions 49 is 70° in this embodiment. The hexagonal head 10 is positioned on the cylindrical head 61. The Venturi tube 47 of the burner head 23 reaches into the upper part 6 of the injector device 34, thereby forming the mixing section 56. The mixing section 56 is enclosed by the circumferential lateral side 66 of the upper part 6, the bottom side 67 of the upper part 6 and the inlet 54 of the Venturi tube 47. A distance 65 between the inlet 54 of the of the Venturi tube 47 and the jet injector 39 is between 1.8 mm and 4.5 mm. The mixing section 56 is further depicted in Fig. 6 and 7.

[0158] Figure 7 shows a cross-sectional view of the assembled gas burner of Figure 2 and The Venturi tube 47 of the burner head 25 is placed in the cylindrical head 61 such that the hydrogen and air can stream from the cylindrical head 61 into the Venturi tube 47. This is facilitated by the form of the Venturi tube 47 which enables a Venturi effect. In particular, the Venturi tube comprises a converging section 40 with decreasing cross-sectional area connected to the cylindrical head 61, followed by a cylindrical throat section 41, which then is followed by a diverging section 42 with increasing cross-sectional area. The 202401327

[0159] Venturi tube 47 increases the gas velocity through a narrow section, creating a low- pressure area that draws in more gas. Thereby a combustible mixture containing hydrogen and air is created that exits the Venturi tube 47 into the burner head 23 and then through the flame ports 31 for combustion.

[0160] The combustible gas enters through the gas coupling piece 15, and the flow of combustible gas 51 travels through the injector device 34 and the mixing section 56, where it mixes with primary air, to the burner head 38.

[0161] An airflow region 50 extends through an opening 18 of a heat shield 27 downwards through and along a wing 4. The cooling air 50 may run along the axial extension of the injector holder 9 and / or the tube 3.

[0162] The injector device is depicted in an enlarged view in the insert of Fig. 7. The jet injector 37 runs through the bottom side 67 into the first, cylindrical head 61 and interior of the second, hexagonal head 10. The jet injector 37 is configured to release combustible gas from the jet injector outlet 39 into the mixing section 56 of cylindrical head 61. Primary air enters through the primary air channels 13. The Venturi tube 47 reaches into the second and first head, such that a mixture of primary air and combustible gas can flow downstream into the Venturi tube 47. The gas mixture flows along the converging section 40, enters the throat section 41 and then the diverging section 42. From there, the gas mixture enters the distribution chamber 57 formed with the burner cap 25 and is available at the flame ports 31.

[0163] In the other enlarged view of Fig. 7, a section of the burner head 23 and the burner cap 25 is depicted. A lateral wing 38 of the burner cap 25 protrudes beyond the edge of the burner head 23 by a protruding distance 52 of approximately 5 mm. The protrusion 38 enhances the flame stability.

[0164] Figure 8 is a cross-sectional view of the burner head 23. The Venturi tube 47 is part of the head 23 and comprises the converging section 40 with decreasing cross-sectional area along the axis 43, followed by the cylindrical throat section 41 , which then is followed by a diverging section 42 with increasing cross-sectional area. Downstream of the Venturi tube 47 a spreader portion 57 follows that is configured to distribute the hydrogen-air mixture 202401327 uniformly to the flame ports 31 of the burner head 23 where they can exit the burner head 23 for combustion. The spreader portion 57 forms the distribution chamber 57 together with the burner cap 25.

[0165] Figure 9 shows a side view of the burner head 23 and in particular a detail focusing on one flame port 31. The flame port 31 is rectangular shaped and comprises sides 45 with height H and a bottom 46 with width W. The height is between 1 and 1.2 mm and the width is between 0.6 and 1 mm. Also the primary axis 43 of the gas burner 1 is depicted. The total cross-section of the flame ports 31 is, in particular chosen, such that the power ratio of the burner 1 is 80 - 110 W / mm2reflecting the caloric value of hydrogen as combustible gas.

[0166] The disclosed gas burners may be used to burn hydrogen as an eco-friendly alternative to natural gases. Heat distribution and / or gas flow specifics of hydrogen combustion is considered and addressed.

[0167] Reference Numerals:

[0168] 1 gas burner

[0169] 2 hob plate

[0170] 3 gas pipe

[0171] 4 wing

[0172] 6 upper part of injector device

[0173] 7 opening of wing for spark plug

[0174] 8 opening of wing

[0175] 9 injector holder

[0176] 10 second head

[0177] 11 gasket

[0178] 12 ignition system

[0179] 13 primary air inlet, air channels

[0180] 14 opening of gasket for thermocouple

[0181] 15 gas coupling piece

[0182] 17 opening of gasket for spark plug

[0183] 18 opening of heat sink 202401327

[0184] 19 central opening of heat sink

[0185] 20 opening of heat sink for thermocouple

[0186] 21 opening of heat sink for spark plug

[0187] 23 burner head

[0188] 24 protrusion of burner cap

[0189] 25 burner cap

[0190] 26 gasket

[0191] 27 heat shield

[0192] 28 opening of burner head for fixation of burner cap

[0193] 29 opening of wing for thermocouple

[0194] 30 Pipe

[0195] 31 flame port

[0196] 34 injector device

[0197] 35 Pipe

[0198] 36 second threading

[0199] 37 jet injector

[0200] 38 wing of burner cap

[0201] 39 jet injector outlet

[0202] 40 converging section of Venturi tube

[0203] 41 throat section of Venturi tube

[0204] 42 diverging section of Venturi tube

[0205] 43 primary axis of burner

[0206] 45 side of flame port

[0207] 46 bottom of flame port

[0208] 47 Venturi tube

[0209] 48 control knob

[0210] 49 channel directions

[0211] 50 airflow region

[0212] 51 flow of combustible gas

[0213] 52 protrusion distance of burner cap

[0214] 53 connection device

[0215] 54 inlet of Venturi tube

[0216] 55 outlet of Venturi tube

[0217] 56 mixing section 202401327

[0218] 57 distribution chamber

[0219] 58 lower part of injector device

[0220] 59 opening of gasket

[0221] 60 distance between gas coupling piece and central axis

[0222] 61 first head

[0223] 62 injection direction

[0224] 63 thermocouple

[0225] 64 spark plug

[0226] 65 distance between the inlet of Venturi tube and jet injector

[0227] 66 lateral side

[0228] 67 bottom side

[0229] 100 gas cooking appliance

[0230] 101 covering plate

[0231] 102 appliance housing

[0232] 103 gas port

[0233] 104 cooking hob a angle between injection direction and channel directions W width of flame port

[0234] H height of flame port

Claims

202401327CLAIMS1. A gas burner (1) for a gas cooking appliance (100), comprising: a connection device (53) configured to receive a combustible gas from a gas supply source; an injector device (34) positioned downstream of the connection device (53), the injector device (34) comprising at least one gas inlet for receiving the combustible gas from the connection device (53), at least one primary air inlet (13), and a mixing section (56) configured to mix the combustible gas and the primary air to a gas mixture; a burner head (23) positioned downstream of the injector device (34), the burner head (23) comprising a plurality of flame ports (31) and a distribution chamber (57) for distributing the gas mixture to the flame ports (31); and means (8, 18, 9) for guiding an airflow through at least one airflow region (50) for cooling at least one of the connection device (53), the injector device (34) and / or the burner head (23), wherein the airflow is different to a flow of primary air and combustible gas.

2. The gas burner (1) according to claim 1 , wherein the connection device (53) comprises a gas coupling piece (15) configured to be connected to the gas supply source, and wherein the burner head comprises a central axis (43) that is perpendicular to its top surface and passes through its geometric center, wherein the distance between the gas coupling piece (15) and the central axis (43) is at least 40 mm.

3. The gas burner according to claim 1 or 2, wherein the means to guide the airflow through the at least one airflow region (50) are configured such that the airflow region (50) extends axially along the connection device (53).

4. The gas burner (1) according to any one of claims 1 - 3, comprising a heat shield (27) radially extending from a central axis (43) of the gas burner (1) and positioned between the injector device (34) and the burner head (23).

5. The gas burner according to claim 4, wherein the heat shield (27) comprises at least one opening (18) through which the at least one airflow region (50) extends.2024013276. The gas burner (1) according to any one of claims 1 - 5, wherein the combustible gas contains hydrogen, preferably more than 80% by volume, more preferably more than 95% by volume, more preferably pure hydrogen.

7. The gas burner according to any one of claims 1 - 6, wherein: the injector device (34) comprises an upper part (6) and a lower part (58) that is connected to the upper part (6) through a jet injector (37) configured to guide the combustible gas from the lower part (58) to the upper part (6); the connection device (53) comprises an injector holder (9) for holding the lower part (58) of the injector device (34); the injector holder (9) is configured to receive the combustible gas from the gas coupling piece (15) and to guide it to the lower part (58) of the injector device (34); the injector holder (9) comprises wings (4) extending radially from a central axis (43) as means to guide an airflow through the at least one airflow region; and the wings (4) at least partially enclose the airflow region (50).

8. The gas burner according to claim 7, wherein: the upper part (6) has an internal cup-shaped geometry and comprises a circumferential lateral side (66) and a bottom side (67); and the burner head (23) comprises a Venturi tube (47), the Venturi tube (47) comprising: an inlet (54) for receiving the gas mixture from the mixing section (56); an outlet (55) for releasing the gas mixture to the distribution chamber (57); a converging section (40) with decreasing diameter downstream of the inlet (54); a throat section (41) with a constant diameter downstream of the converging section 40; a diverging section (42) with increasing diameter downstream of the throat section (41) and upstream of the outlet (55); and wherein the Venturi tube (47) reaches into the upper part (6) of the injector device (34), thereby forming the mixing section (56) enclosed between the circumferential202401327 lateral side (66) of the upper part (6), the bottom side of the upper part (6) and the inlet (54) of the Venturi tube (47).

9. The gas burner (1) according to claim 8, wherein the inner diameter of the throat section (41) of the Venturi tube (47) is in the range between 2.5 mm and 3 mm.

10. The gas burner (1) according to claim 8 or 9, wherein a distance between the inlet (54) of the of the Venturi tube (47) and an outlet of the jet injector (39) is between 1.8 mm and 4.5 mm.

11. The gas burner (1) according to any one of claims 8 - 10, wherein the upper part (6) comprises the at least one primary air inlet (13) which comprises a plurality of primary air channels (13).

12. The gas burner (1) according to any one of claims 1 - 11, wherein at least one of the flame ports (31) is a slit that comprises sides (45) with a height (H) and a bottom (46) with a width (W), wherein the height (H) is between 1 mm and 1.2 mm, and wherein the width (W) is between 0.6 mm and 1 mm.

13. The gas burner (1) according to any one of claims 1 - 12, wherein the number and cross-section of the flame ports (31) is configured such that the power ratio of the burner during operation is in the range 80 - 110 W / mm2, the power ratio being the quotient of the power output of the gas burner (1), which is the product of the mass flow rate of the gas mixture and its calorific value, and the surface area of the top side of the burner head (23).

14. A cooking hob (104) with a gas burner (1) according to any one of claims 1 - 13.

15. A gas cooking appliance (100) with a gas burner (1) according to any one of claims 1 - 13 and / or with a cooking hob (104) according to claim 14.

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