Burner arrangement for a heating device and heating device

Abstract

The invention relates to a burner arrangement (3) for a heating appliance (1) designed for the combustion of a fuel gas containing at least 80 percent hydrogen. The burner arrangement (3) has a burner outlet element (15) which defines a burner cavity (33) and has at least one outlet area (16) as a field with outlet openings (17) for the fuel gas from the burner cavity (33). Adjacent to and perpendicular to the at least one outlet area (16) is a primary flame chamber (28) of the burner outlet element (15).The burner arrangement (12) further comprises an ignition device (18) with at least one electrode (20, 21) that forms an ignition spark in an ignition spark generation section (29), wherein the ignition spark generation section (29) is positioned relative to the burner outlet element (15) such that it is located outside any primary flame chamber (28), and a lateral distance A (26) of the ignition spark generation section (29) to the primary flame chamber (28) satisfies the following condition: A ≤ 5 mm + D / 3. Here, D is a burner distance (30) of the ignition spark generation section (29) towards the burner outlet element (15). Furthermore, a heating device (1) with a burner arrangement (3) as proposed here is proposed.

Description

[0001] The invention relates to a burner arrangement comprising an ignition device for a heating appliance and a heating appliance that can be operated with hydrogen and / or a hydrogen-containing fuel gas.

[0002] Hydrogen as a fuel gas or as an additive to fuel gases is becoming increasingly important, and significant efforts are being made to adapt new and existing heating appliances for its operation. This applies not only to large systems but also to wall-mounted units for heating water and, more generally, to heating appliances for building heating and / or hot water supply.

[0003] Burners for use in such heating appliances are widely known. Such a burner is often mounted on a burner door, which is installed in a combustion chamber with a surrounding heat exchanger. The burner can comprise a burner body with at least one perforated area, also called a burner outlet element, from which a premixed, combustible fuel gas-air mixture (combustion mixture) can exit. The combustion mixture flows from a mixture channel through the burner door into the burner and exits through the burner outlet element into the combustion chamber, where it combusts. The burner can be cylindrical, (semi-)spherical, or flat.

[0004] Hydrogen differs from previously used fuel gases in several respects regarding its combustion and ignition behavior. In particular, a hydrogen flame is almost invisible to the human eye (but emits radiation in the ultraviolet spectral range), releases less heat than the combustion of carbon-based fuels, yet reaches higher temperatures. Furthermore, a significantly lower ignition energy is required for the ignition system to start a hydrogen-burning burner.

[0005] The ignition device can be located in or in the immediate vicinity of a burner outlet element in the combustion chamber and, when subjected to electrical voltage during commissioning, generates an ignition spark. For this purpose, the ignition device can comprise two electrodes, one of which is connected to the electrical ground of the heating appliance. Alternatively, the electrical ground can be formed by a component of the burner, for example, the burner itself or the burner outlet element, so that an ignition spark forms between one electrode and the grounded component, which represents the second electrode.

[0006] The aforementioned differing properties of a hydrogen flame lead to increased demands on the ignition electrode, particularly its heat resistance. This can cause accelerated wear on at least one of the ignition electrodes, which promotes delayed ignition, often resulting in a hard ignition. In addition to the necessary replacement of the ignition electrodes, this can also lead to damage to the heating device.

[0007] To reduce the risk of damage to the heating device and to ensure robust ignition operation, DE 10 2022 124 819 A1 proposes providing a primary and a secondary ignition device and, after an unsuccessful ignition attempt using the primary ignition device, initiating a new ignition attempt using the secondary ignition device. Disadvantages of this solution include the installation of two ignition devices and its failure to reduce wear on the ignition devices due to hydrogen combustion.

[0008] WO 2021 / 078 949 A1 proposes, for the ignition of a hydrogen-powered burner, that in a first phase of the ignition process, a combustion mixture with a combustion air ratio (lambda) of at least 1.85 is supplied and ignited by the ignition device. Subsequently, in a second phase after ignition, a combustion mixture with a reduced combustion air ratio compared to the first phase is supplied. A similar solution is proposed in DE 10 2022 124 819 A1. This method also fails to reduce the wear of an ignition device during hydrogen combustion.

[0009] The object of the present invention is to at least partially solve the problems described with reference to the prior art and, in particular, to propose a burner arrangement with an ignition device and a heating device that can reduce operational wear of the ignition device and thus enable robust ignition operation of a hydrogen-burning burner arrangement or a heating device comprising such a device.

[0010] Furthermore, the invention should not significantly increase the complexity of a burner arrangement and a heating device.

[0011] These problems are solved by the features of the independent claim. Further advantageous embodiments of the solution proposed here are specified in the dependent claims. It should be noted that the features listed in the claims can be combined with one another in any technologically meaningful way and define further embodiments of the invention. Furthermore, the features specified in the claims are further specified and explained in the description, which also presents further preferred embodiments of the invention.

[0012] This is achieved by a burner assembly for a heating appliance, designed for the combustion of a fuel gas containing at least 80 percent hydrogen. The burner assembly has a burner outlet element that defines a burner cavity and includes at least one discharge area as a field with discharge openings for the fuel gas from the burner cavity. Adjacent to and perpendicular to the at least one discharge area is a primary flame chamber of the burner outlet element, as well as an ignition device with at least one electrode that generates an ignition spark in an ignition spark generation section.The ignition spark generation section is positioned relative to the burner outlet element such that it is located outside any primary flame chamber, and a lateral distance A of the ignition spark generation section to the primary flame chamber satisfies the following condition: A ≤ 5 mm + D / 3, where D is a burner distance of the ignition spark generation section towards the burner outlet element.

[0013] The burner arrangement can be used with any heating appliance, particularly premixing or semi-premixing appliances designed for heating a building and / or providing heated drinking or domestic hot water. Specifically, the heating appliance can be a gas-fired boiler with a delivery system that draws in a mass flow of combustion air, to which a mass flow of fuel gas, corresponding to a predetermined combustion air ratio, is added via a gas valve. However, the heating appliance can also use oxidizers other than combustion air. The combustion mixture of fuel gas and combustion air can then be fed via a mixture channel to a burner arrangement proposed here. This arrangement comprises a burner with a burner cavity connected to the mixture channel, into which the combustion mixture can flow before exiting through a burner outlet element into a combustion chamber of the heating appliance, where it is combusted.The combustion chamber can be thermally coupled to at least one heat exchanger, which transfers the heat generated during combustion to a heat transfer medium, such as heating water or domestic hot water. This heat exchanger can be designed to cool the combustion gases to a temperature below the boiling point of water, thus utilizing the resulting condensation heat. Such a heating appliance can also be called a condensing boiler. The combustion gases can then be routed through a flue on the heating appliance to a building's exhaust system. The exhaust system can be a single- or multi-flue system. Multi-flue systems are those to which several heating appliances are connected.The heating appliances or the exhaust system may have backflow preventers that prevent exhaust gas from flowing from one heating appliance into another and potentially escaping. The heating appliance may, in particular, be a wall-mounted unit.

[0014] The heating appliance can operate at various points within a modulation or power range, thus enabling operation at different output levels. To increase efficiency and service life, modern heating appliances often feature a wide modulation range, for example, from 2.5 kilowatts [kW] to 21 kW, or a modulation ratio (ratio of maximum to minimum power) of 1:5. Due to the highly variable flame shapes and characteristics, a wide modulation range places high demands on the burner.

[0015] The heating appliance and burner assembly are designed for the combustion of (pure) hydrogen or a fuel gas with a high hydrogen content. Hydrogen as a fuel is advantageous due to the possibility of sustainable production. The hydrogen content in the fuel gas can be at least 80%, at least 90%, or, in particular, at least 95%.

[0016] The burner or burner outlet element can be made of any suitable material. Stainless steel is frequently used due to its good temperature and corrosion resistance, as well as its availability.

[0017] The geometric shape of the burner can be any form. In particular, cylindrical or flat burners are known. A burner cavity can be connected to the mixture channel of the heating device, and incoming fuel gas can be directed from the burner cavity into the combustion chamber of the heating device via fields of outlet openings arranged in a burner outlet element, forming an outlet area, and combusted.

[0018] The burner outlet element can be understood as a section of the burner surface with openings through which the combustion mixture flows. These openings (holes) are also referred to as exhaust ports. The area of ​​a combustion zone can be considered the area defined by the exhaust ports or exhaust zones, i.e., the smallest contiguous area in which all exhaust ports are arranged.

[0019] The burner outlet element can form a monolithic unit with the burner or be detachably connected to it, for example by means of a screw connection.

[0020] The burner outlet element can have a shape that is at least largely flat (planar) or a three-dimensional shape. A three-dimensional shape can consist of a raised or recessed area relative to the burner, or another form, such as a bulge.

[0021] The burner outlet element and the burner can have the same material thickness and be located within a known range. However, especially if the burner outlet element is detachably connected to the burner, different material thicknesses for the burner outlet element and the burner are also conceivable.

[0022] The exhaust openings in the combustion zone can be assigned to one or, in particular, several planar exhaust areas or fields. For example, the cumulative (summed) area of ​​the exhaust openings / fields of an exhaust area can be more than 3 percent [%] and less than 12.5 percent of the cumulative area of ​​all exhaust openings. A distance to an exhaust area can refer to the distance to a perimeter of the exhaust area, where the perimeter can be defined by a connecting line of all outer exhaust openings of an exhaust area. The perimeter can enclose an area within which all exhaust openings of the one or individual exhaust area / field lie.

[0023] A space without outlet openings can be arranged between the outlet areas / fields. The burner outlet element has one or more outlet areas / fields in which the outlet openings are grouped. It is possible for a plurality of fields (especially of equal size) to be provided. The fields are separated or spaced apart from each other by a gas-impermeable section of the burner outlet element, this field spacing being a multiple of the hole spacing of the outlet openings within the field, for example, even greater than 20% or even greater than 30% of a field dimension. By way of example, the minimum distance between two outlet areas can be at least 3 millimeters [mm] and not more than 100 millimeters. By way of example, the ignition device according to the present invention can be...at least one electrode of the ignition device is arranged in the area between two outlet areas.

[0024] For example, the distance between one outlet opening and the nearest outlet opening in the same outlet area / field can be less than 1 millimeter [mm]. In any case, the distance should be chosen to ensure the mechanical stability of the outlet openings.

[0025] The outlet openings can have any shape, in particular circular, rectangular, square, or elongated shapes. It is also possible to combine different shapes within a single outlet area. The shape of the outlet areas or outlet openings is irrelevant for the present invention.

[0026] The arrangement of the exhaust openings within an exhaust region / field is also arbitrary. The geometric shape of the exhaust region, as the outer contour of all exhaust openings within the exhaust region, can be, for example, rectangular, square, approximately circular, oval, or even rhombus- or polygonal. The orientation of non-rotationally symmetrical intake areas relative to the orientation of the combustion zone can also be varied. Generally, the arrangement of the exhaust openings within an exhaust region should be at least approximately uniformly distributed.

[0027] For example, the (flat) burner outlet element can have at least eight outlet areas / fields.

[0028] The outlet openings and / or outlet areas can define a primary flame chamber perpendicular to the surface of the burner outlet element on the side of the burner cavity facing away from the burner cavity. In this respect, a primary flame chamber can be understood, in particular, as an (imaginary) cylinder with the outlet area / field as its base, the height of which can lie in the direction of the combustion mixture's outflow from the burner outlet element. The perpendicular direction here refers to the direction perpendicular to a tangential plane of the surface of the burner outlet element in the respective outlet opening and / or outlet area. This tangential plane can be referenced to the center of the outlet opening or outlet area.

[0029] The ignition device of the burner assembly comprises at least one electrode. An ignition spark can form in a known or predefined spark-generating section of the electrode due to an ignition voltage between the electrode and an electrical ground point. The ground point can be formed by a second electrode or by a component of the burner, in particular the burner itself or the burner outlet element. The spark-generating section defines an area in which an ignition spark forms during normal operation of the ignition device.

[0030] The at least one electrode is arranged relative to the outlet openings or outlet areas such that the ignition spark forms outside or adjacent to each primary flame chamber, or the ignition spark generation section is located outside or adjacent to the primary flame chamber. In other words, the at least one electrode of the ignition device is arranged such that it is not directly exposed to the (currently) flowing combustion mixture, which advantageously reduces the temperature of the ignition device during burner operation and thus increases its service life. Therefore, the ignition device can be arranged such that the ignition spark generation section is located in a lateral boundary region around an outlet opening and / or an outlet area.

[0031] According to one embodiment, the entire electrode (at least one of the electrodes) can be located outside the primary flame chamber. Advantageously, this protects the entire electrode from the high temperatures of the primary flame chamber.

[0032] Alternatively, only part of the electrode, including the ignition spark generation section of at least one electrode, can be located outside the primary flame chamber. This means that temperature peaks typically occur at the ends of the electrodes, i.e., in the area of ​​the ignition spark generation section, thus significantly increasing the service life of the ignition system.

[0033] Furthermore, the at least one electrode of the ignition device is arranged such that a maximum lateral distance A of the ignition spark generation section to the nearest / adjacent primary flame chamber is determined, taking into account a burner distance D of the ignition spark or the ignition spark generation section to the burner surface, wherein the lateral distance A of the ignition spark generation section to the nearest / adjacent primary flame chamber fulfills the following condition: A ≤ 5 Millimeter + D 3 If the ignition spark generation section is not aligned parallel to the burner surface, the average burner distance D of the ignition spark generation section from the burner surface can also be used as the burner distance D. In an ignition device that uses the burner outlet element as a ground point, and where the burner distance D thus extends from the burner outlet element to the electrode, the average burner distance D can correspond to half the distance of one electrode from the burner outlet element, which forms the ground point. Therefore, the possible maximum lateral distance A of the ignition spark generation section from the primary flame chamber increases with increasing burner distance D.

[0034] This establishes a limited circumferential area with a lateral distance A adjacent to the primary flame chamber for ignition spark generation, whereby this area can be selected to be wider with increasing distance of the ignition spark generation section from the burner surface.

[0035] This limited circumference maintains a lateral safety distance of at least 1.5 mm to the primary flame chamber. This lateral safety distance can further minimize the risk of overheating of the ignition device. The safety distance can be selected or determined based on the displacement and / or (temporary) change of the flame, for example, flame vibration and / or movement / displacement that can occur during modulation processes. The lateral safety distance can also compensate for or account for tolerances, such as the alignment of the outlet openings relative to the surface of the burner outlet element, deviations of which can lead to a widening of the primary flame chamber.

[0036] If the lateral distance A between the ignition spark generation section and the primary combustion chamber is exceeded, there is a particular risk that an ignition spark will fail to ignite the combustion mixture, thus preventing the heating appliance from being operated. Furthermore, an excessively large lateral distance A increases the risk of delayed ignition, often referred to as a hard ignition, which is accompanied by loud noise and can damage the heating appliance. However, the lateral distance A should also take into account geometric tolerances, especially those relating to the burner position in relation to the ignition device or the ignition spark generation section, which could result in the ignition spark generation section being located within the primary combustion chamber.

[0037] According to one embodiment, the ignition spark generation section can at least partially meet the condition A ≤ 5 Millimeter + D 3 fulfill. According to a further embodiment, the entire ignition spark generation section can also fulfill the aforementioned condition.

[0038] According to one embodiment, the lateral distance A satisfies the following condition: A ≤ 5 Millimeter + D 5 In this design, the maximum lateral distance A of the ignition spark generation section to the nearest primary flame chamber is thus reduced, thereby bringing the ignition spark generation section closer to the mass flow of combustion mixture exiting through the outlet opening or outlet area. This condition is particularly relevant when the fuel gas contains less than 95 percent hydrogen.

[0039] According to one embodiment, the electrode gap Z of the ignition device, in which the ignition spark or the ignition spark generation section forms, can be in a range of 0.5 mm to 15 mm. The electrode gap Z denotes the distance of at least one electrode from the ground point, i.e., the distance from a first electrode to a second electrode (forming a ground point), or also the distance from one electrode to a burner outlet element forming the ground point. In other words, the electrode gap Z can correspond to the length of the ignition spark or the ignition spark generation section.

[0040] According to a further embodiment, the electrode gap Z can be in a range between 1.0 mm and 3.5 mm. Advantageously, a smaller gap requires less electrical power to generate the ignition spark. This can advantageously reduce the wear of the at least one electrode and its insulators, thus increasing the service life of the ignition device. For example, a hydrogen-containing fuel gas requires less ignition energy than carbon-containing fuel gases, which makes it possible to reduce the electrode gap Z, which represents the length of the resulting ignition spark.

[0041] The burner outlet element can have a plurality of outlet areas as fields, each with a plurality of outlet openings, wherein each field has a gas-impermeable frame having a frame width of at least 2.5 mm, or particularly 3.0 mm. The frame can be formed by a gas-impermeable section of the burner outlet element that separates or spaces the fields apart, this field spacing being a multiple of the hole spacing of the outlet openings within the field, for example, even greater than 20% or even greater than 30% of a field dimension. Preferably, all fields have such a frame. It is particularly preferred that the ignition spark generation section is positioned opposite such a frame.

[0042] It is possible for a multitude of outlet areas to be provided as fields with outlet openings arranged within a predetermined combustion zone of the burner outlet element, which is surrounded (circumferentially or enclosingly) by a gas-impermeable boundary region, with the ignition spark generation section positioned opposite this boundary region. The boundary region can be formed by outer sections of the (field) frames. The combustion zone can have an outer (circumferential) elevation or depression that constitutes a boundary, with the boundary region being defined between the outermost fields and this boundary.

[0043] According to one embodiment, the burner can have a flame arrestor. This can be arranged between the burner surface and the mixture channel and can be made of a known material. A flame arrestor can minimize the risk of flame flashback.

[0044] A further aspect is addressed in the proposal for a heating appliance featuring the burner arrangement presented here. The heating appliance is designed for the combustion of a fuel gas containing hydrogen. The burner arrangement can be located, at least partially, within a combustion chamber of the heating appliance.

[0045] The details, features, and advantageous designs discussed in connection with the burner arrangement can also occur in the heating appliance presented here, and vice versa. In this respect, full reference is made to the explanations provided there for a more detailed characterization of the features.

[0046] It should be noted as a precaution that the numerical terms used here ("first", "second", etc.) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and thus do not necessarily dictate any dependency and / or sequence between these objects, quantities, or processes. Should a dependency and / or sequence be required, this is explicitly stated here, or it will be obvious to a person skilled in the art upon studying the specific configuration described. Where a component can occur multiple times ("at least one"), the description of one of these components may apply equally to all or some of the multiple components, but this is not mandatory.

[0047] This proposal therefore presents a burner arrangement for a heating appliance and a heating unit that at least partially solves the problems described with reference to the state of the art. In particular, the burner arrangement and the heating unit enable a permanently robust ignition operation of the heating unit, thereby reducing the wear of the ignition electrodes.

[0048] Furthermore, the burner arrangement can be easily retrofitted to existing heating appliances by integrating an ignition device suitable for the heating appliance and corresponding to the invention into the burner arrangement.

[0049] The invention and its technical context are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not intended to be limited by the exemplary embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the situations described in the figures and combine them with other components and findings from the present description. It should be emphasized that the figures, and especially the depicted dimensions, are only schematic. They show: Fig. 1: a heating device proposed here, Fig. 2: a burner arrangement according to the prior art, Fig. 3: a burner arrangement proposed here, Fig. 4: a further representation of a burner arrangement proposed here, and Fig. 5: a sectional view of a burner arrangement proposed here.

[0050] Fig. 1 Figure 1 shows an exemplary and schematic representation of a proposed heating appliance 1. This appliance can draw in combustion air via a combustion air supply 4 through a conveying device 2 and add hydrogen-containing fuel gas from a gas supply 13 to the drawn-in mass flow of combustion air via a gas valve 5. The combustion mixture of fuel gas and combustion air can then be fed via a mixture channel 11 to a burner assembly 3 located in a combustion chamber 8. The burner assembly 3 can be attached to a burner door 6 and connected to the mixture channel 11 in such a way that the combustion mixture can flow into a burner cavity 33 surrounded by a burner 14. Subsequently, the combustion mixture can exit the burner assembly 3 via a burner outlet element 15 and be combusted. The burner outlet element 15 can be integrated into the burner 14 or, for example, attached to it by means of a screw connection 25.The burner assembly 3 can be arranged on a burner door 6. An ignition device 18 and a flame monitoring device 12 can also be arranged on the burner door 6. The flame monitoring device 12 can include a UV sensor, i.e., a sensor for detecting ultraviolet radiation. A heat exchanger 19 can be arranged on the combustion chamber 8, which can transfer the heat generated during combustion to a heat transfer medium, for example, heating water.

[0051] The combustion products can be fed from the combustion chamber 8 to an exhaust pipe (exhaust system) 10 via an exhaust pipe 9. The heating appliance 1 may also have a control and regulating unit 7. The heating appliance 1 is designed for the combustion of a fuel gas containing at least 80% hydrogen. For this purpose, the burner 3 may have a burner outlet element 15 suitable for the combustion of hydrogen.

[0052] Fig. 2 Figure 14 also shows an exemplary burner arrangement 3 according to the prior art. The burner 14 comprises a burner outlet element 15 with outlet areas 16, in which outlet openings 17 are grouped, and is attached to the burner door 6. A first electrode 20 and a second electrode 21 of the ignition device 18 are arranged such that they lie within a developing flame of the burner 3. The first electrode 20 is a live electrode connected to an insulator 31, and the second electrode 21 is connected to the electrical ground of the heating device 1. A disadvantage of arranging the ignition device 18 within a developing flame is that the ignition device 18, or rather the electrodes 20 and 21, become too hot and consequently wear out more quickly.

[0053] The Fig. 3 Figure 1 shows a burner 14 with a burner outlet element 15, in which outlet openings 17 are grouped into outlet areas 16. The entirety of all outlet areas 16 (i.e., the smallest area in which all outlet areas 16 are arranged) can form a combustion zone 34. A first position 22, a second position 23, and a third position 24 of the ignition device 18, corresponding to the invention, are shown. The combustion zone 34 has a circumferential gas-impermeable edge region 35.

[0054] Fig. 4 Figure 1 shows a more detailed representation of an outflow region 16, which comprises outflow openings 17, and a position of the ignition device 18 with first electrode 20 and second electrode 21. The electrodes 20, 21 are arranged such that the ignition spark forms in an ignition spark generation section 29 proposed according to the invention. This ignition spark generation section 29 is arranged outside of, or laterally around, a primary flame chamber 28. The first electrode 20 and the second electrode 21 have a (minimum) electrode gap Z 27 in which an ignition spark forms. The electrode gap Z 27 can thus also be understood as the length of the ignition spark or of the ignition spark generation section 29. A maximum possible lateral distance A 26 of the developing ignition spark or the ignition spark generation section 29 to the primary flame chamber 28 defines an arrangement of the at least one electrode 20, 21 with respect to the outflow area 16 or 28.the outlet openings 17 fixed.

[0055] Fig. 5 Figure 1 shows an exemplary and schematic cross-sectional view of the burner outlet element 15 through outflow regions 16. A lateral distance D 30, which can also be understood as a vector, extends from the outflow region 16 in a normal direction to a tangent plane 32 of the outflow region 16. Thus, in the primary flame chamber 28, all vectors emanating from the outflow region 16 lie in a normal direction. According to the invention, the ignition spark or the ignition spark generation section 29 does not form in the primary flame chamber 28, thereby preventing overheating of the electrodes 20, 21 of the ignition device 18.

[0056] The lateral distance A 26 depends on the burner distance D 30 of the ignition spark generation section 29 from the burner outlet element 15. The burner distance D 30 can also be understood as the vector of an outflow direction 30 of the combustion mixture from the outlet area 16 of the burner outlet element 15 into the combustion chamber 8. The lateral distance A 26 is defined as a function of the burner distance D 30 as A = 5 mm + D / 3. Thus, the lateral distance A 26 increases with increasing burner distance D 30.

[0057] An arrangement of the at least one electrode 20, 21 of the ignition device 18 such that the ignition spark generation section 29 can form at a maximum lateral distance A 26, which depends on the burner distance D 30, ensures a permanently robust ignition operation of the hydrogen-powered heating device 1. Advantageously, the wear of the electrodes 20, 21 of the ignition device 18 can be significantly reduced, since they are not exposed to the high temperatures in the primary flame chamber 28. Reference symbol list

[0058] 1 Heating unit 2 Conveyor device 3 Burner arrangement 4 Combustion air supply 5 Gas valve 6 Burner door 7 Control and regulating unit 8 Combustion chamber 9 Exhaust pipe 10 Exhaust system 11 Mixture channel 12 Flame monitoring 13 Gas supply 14 Burner 15 Burner outlet element 16 Outlet area 17 Outlet opening 18 Ignition device 19 Heat exchanger 20 First electrode 21 Second electrode 22 First position 23 Second position 24 Third position 25 Screw fastening 26 Lateral clearance A 27 Electrode clearance Z 28 Primary flame chamber 29 Ignition spark generation section 30 Burner clearance D, exhaust direction of combustion mixture 31 Insulator 32 Tangential plane 33 Burner cavity 34 Combustion zone 35 Edge area

Claims

1. Burner arrangement (3) for a heating appliance (1), designed for the combustion of a fuel gas containing at least 80 percent hydrogen, comprising a burner outlet element (15) which defines a burner cavity (33) and includes at least one outlet area (16) as a field with outlet openings (17) for the fuel gas from the burner cavity (33), wherein adjacent to and in the normal direction to the at least one outlet area (16) there is a primary flame chamber (28) of the burner outlet element (15), and an ignition device (18) comprising at least one electrode (20, 21) which forms an ignition spark in an ignition spark generation section (29), wherein the ignition spark generation section (29) is positioned relative to the burner outlet element (15) such that it is arranged outside each primary flame chamber (28),wherein a lateral distance A (26) of the ignition spark generation section (29) to the primary flame chamber (28) satisfies the following condition: A ≤ 5 mm + D / 3, where D is a burner distance (30) of the ignition spark generation section (29) towards the burner outlet element (15).

2. Burner arrangement (3) according to claim 1, wherein the side distance A (26) satisfies the following condition: A ≤ 5 mm +D / 5.

3. Burner arrangement (3) according to one of the preceding claims, wherein the ignition device (18) has two electrodes (20, 21) which have a minimum electrode gap Z (27) in the area of ​​the ignition spark generation section (29) which is in the range of 0.5 mm to 15 mm.

4. Burner arrangement (3) according to claim 3, wherein the minimum electrode spacing Z (27) is in a range of 1.0 mm to 3.5 mm.

5. Burner arrangement (3) according to one of the preceding claims, wherein the burner outlet element (15) is flat, curved or cylindrical.

6. Burner arrangement (3) according to one of the preceding claims, wherein the burner outlet element (15) has a plurality of outlet areas (16) as fields, each with a plurality of outlet openings (17), wherein the fields each have a gas-impermeable frame having a frame width of at least 2.5 mm.

7. Burner arrangement (3) according to one of the preceding claims, wherein a plurality of outlet regions (16) are provided as fields with outlet openings (17) arranged in a predetermined combustion zone (34) of the burner outlet element (15) which is surrounded by a gas-impermeable edge region (35), wherein the ignition spark generation section (29) is positioned opposite this edge region (35).

8. Heating appliance (1) comprising a burner arrangement (3) according to one of the preceding claims.

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