Burner having an exhaust gas recirculation device
The burner with an exhaust gas recirculation device using a jet pump and specific geometric ratios addresses intake capacity and turbulence issues, achieving efficient combustion performance and nitrogen oxide reduction for diverse fuels.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- KUESOL ADDITIVE GMBH
- Filing Date
- 2025-12-17
- Publication Date
- 2026-06-25
AI Technical Summary
Existing burners face limitations in exhaust gas intake capacity and turbulence, leading to inefficient nitrogen oxide reduction and inability to separately control fuel gas and combustion air volumes, particularly when using different fuels like methane and hydrogen.
A burner with an exhaust gas recirculation device featuring a jet pump operated by combustion air, incorporating a drive gap and specific geometric ratios for flow channels to optimize combustion stoichiometry and enable separate control of fuel gas and combustion air volumes, allowing for larger exhaust gas post-combustion and reduced nitrogen oxide formation.
The solution enables efficient exhaust gas recirculation, optimizing combustion performance and reducing nitrogen oxide emissions, while maintaining independent control over fuel gas and combustion air volumes, suitable for various fuels including methane, hydrogen, and their mixtures.
Smart Images
Figure DE2025101196_25062026_PF_FP_ABST
Abstract
Description
[0001] KPSP 008 WO T4b.docx
[0002] Burner with an exhaust gas recirculation device
[0003] The invention relates to a burner with an exhaust gas recirculation device having the features of the preamble of claim 1.
[0004] US Patent 2018 / 0080647A1 discloses a method and a combustion device for reducing nitrogen oxide formation. This method employs a Venturi nozzle positioned just upstream of the burner nozzle to draw in exhaust gas from outside the furnace chamber and dilute it within the fuel gas mixture. Since the burner features an open exhaust gas path outside the combustion chamber tube and draws exhaust gas from within the furnace chamber, a combination with an upstream recuperator is generally possible. However, the exhaust gas intake capacity is limited by the fact that only small openings can be provided in the wall of the Venturi nozzle at its constriction point to avoid excessively impeding the flow of the air-fuel gas mixture inside. Despite this limitation, the radial entry of the exhaust gas into the Venturi nozzle creates turbulence when it encounters the gas mixture flowing past at a right angle.A further disadvantage is that the mixture of fuel gas and combustion air must already be formed before entering the Venturi nozzle, and therefore the flow velocities of air and fuel gas can no longer be individually controlled. The object of the invention is therefore to improve a burner of the type mentioned above in such a way that a larger volume of exhaust gas can be post-combusted in order to eliminate larger proportions of nitrogen oxides. Furthermore, the volume flows of fuel gas and combustion air should be separately adjustable, in particular to enable the combustion of different fuel gases such as methane and hydrogen, or mixtures thereof, with the same burner.
[0005] This problem is solved by a burner having the features of claim 1.
[0006] The burner according to the invention has an exhaust gas recirculation device with a jet pump operated by combustion air, which has a drive gap formed upstream of the mixing plane of the combustion gases flowing into the combustion chamber tube, in front of the combustion chamber tube. This ensures that the flow of the combustion gas itself remains completely unaffected. Instead, the combustion gas is directed directly to the burner nozzle, where the mixture of combustion air and aspirated exhaust gas is added.
[0007] The invention provides the following measures for a burner, in particular a so-called cold air burner, which uses fresh air as an oxidizing agent and which is not significantly preheated above the ambient temperature, in order to optimize both the burner performance and the nitrogen oxide reduction:
[0008] - Downstream of the jet nozzle and the exhaust gas intake opening(s), an exhaust gas flow channel is formed between an inner surface of an external eductor and an outer surface of an internal flow control element.
[0009] The inclinations of the surface areas of the flow-guiding element and the ductor are chosen such that the ratio of the area of a trapping slot to an outlet slot is between 1:7 and less than 1:1. For an annular slot, the areas refer to the area of the annular slot. For a series of individual openings along an annular contour, which function like an annular slot, the area refers to the sum of all the clear opening areas.
[0010] Preferably, the ratio of the area of the trapping slot to the outlet slot is between 1:2 and 2:5. Preferably, the ratio of the area of a trapping slot to an outlet slot is between 1:7 and less than 1:1, or between 2:5 and less than 5:5.
[0011] The width of the trapping gap is preferably at least 1% of the mean diameter of the trapping gap, for example 0.7 mm for a diameter of 70 mm.
[0012] The geometry provided according to the invention optimizes the stoichiometric conditions of combustion and thereby directly influences the burner output. For example, it is found that with air as an oxidizer, per 1 mm 2 With a combustion gap area, a maximum burner output of 0.1 kW to 0.3 kW can be achieved. With different oxidizers, the combustion gap area changes inversely proportional to the change in oxygen content.
[0013] At the same time, it follows that per 1 mm 2The area of the exhaust gas intake opening with air as an oxidizer is designed for a maximum burner output of 0.001 kW to 0.1 kW, and here too, the area of the exhaust gas intake opening may need to be adjusted inversely proportional to the change in oxygen content.
[0014] When the oxygen content in the oxidizer changes from 21% in air to another oxidizer, all surfaces change in proportion to the increase or decrease in the oxygen content, so that as a result the ratios of the surfaces related to each other in a burner designed according to the invention remain constant.
[0015] A preferred embodiment links the aforementioned relationships such that the area of the intake gap is smaller than the area of the intake gap, and the latter is smaller than or at most equal to the area of the outlet gap. This results in a gradual widening in the direct flow path. This creates the necessary negative pressure to achieve a suction effect and also accounts for the increase in volume during the transition from supplied air to the air-exhaust mixture.
[0016] It is also advantageous if the ratio of the area of the exhaust gas intake opening to the area of the trap gap is between 1:3 and 3:1.
[0017] Preferably, the ratio of the area of the trap gap to the area of the drive gap is between 1 : 20 and 10 : 20.
[0018] The recirculation rate can be controlled by the size of the flow gap formed at the beginning of the flow channel. The recirculation rate indicates the ratio of the exhaust gas volume flow to the combustion air volume flow.
[0019] The width of the exhaust intake opening should be between 6 mm and 15 mm. It has been determined that a high exhaust gas flow rate can be achieved within this range and unstable combustion is avoided, with the aforementioned dimension surprisingly being largely independent of the diameter of the exhaust intake opening.
[0020] The minimum height of the trap gap should be 1% of the diameter, for example at least 0.7 mm for a diameter of 70 mm.
[0021] The exhaust gas flow channel has a length L1, which is measured between its beginning at the trap gap, downstream of the exhaust gas intake opening, and an end where the exhaust gas flow channel opens into the combustion chamber tube at a distance L2 from the burner nozzle. The ratio of L1 : L2 should be greater than zero but no more than 2:1.
[0022] The volume of the exhaust gas-air mixture flowing past and through the burner nozzle is limited by the minimum cross-section of the nozzle flow area between the combustion chamber tube and the burner nozzle, with the ratio between the outlet area and the minimum nozzle flow area preferably being between 7:20 and 18:20.
[0023] The preferred design of the exhaust gas recirculation device further provides that the inner pipe opens into or onto an inlet opening of an eductor, the diameter of which is larger than that of the combustion chamber pipe. The combustion chamber pipe is connected to this eductor, with an annular exhaust gas intake opening formed between the outer surface of the inner pipe and the edge of the inlet opening. At the exhaust gas intake opening, the recuperator burner opens towards the furnace chamber, into which the recuperator burner projects, allowing exhaust gas to be drawn in directly from there.
[0024] In a further improved design, the annular jet gap can be conically angled inwards. This results in a more homogeneous mixing of combustion air and exhaust gas before this mixture reaches the axial position where the fuel gas is added.
[0025] The drive gap is preferably annular, in particular circular, and converges in the direction of flow. Similarly, the exhaust gas intake opening and / or the collection gap are also annular, in particular circular.
[0026] "Annular" within the meaning of the invention refers not only to a circular cross-section, but also to a meandering cross-section of the drive gap, particularly when the jet pump is connected to an upstream heat transfer body with a linked arrangement of several combustion air outlet openings. The drive gap is adapted to the shape of the outlet openings on the end face of the heat transfer body by its meandering shape. In this case, the shape of the exhaust gas intake opening and / or the collection gap preferably follows the shape of the drive gap and is therefore also meandering. The drive gap is generally continuous, with only a few support points provided within it to maintain an outer nozzle ring at a distance from an inner tube or the like.
[0027] Furthermore, it is possible to design the air gap as an alternating sequence of closed and open cross-sectional areas along a circumferential line. Such a design of the air gap is particularly feasible using additive manufacturing processes and serves the specific purpose of increasing the flow velocity of the combustion air by reducing its cross-sectional area in the flow channel, thereby achieving a jet pump effect. In many cases, a converging air gap shape is not required for this purpose.
[0028] Preferably, the opening of the propulsion gap is formed within the cross-section of the trapping gap, so that the propulsion jet is directed directly into the trapping gap. It can also be advantageous if the jet direction of the fresh air jet entering through the propulsion gap is precisely aligned with the centerline of the trapping gap, so that all flow directions are aligned.
[0029] According to the invention, the jet pump creates a burner for dilute combustion through exhaust gas intake. Exhaust gas recirculation reduces nitrogen oxide formation, whether using natural gas, hydrogen, or other fuels such as propane, butane, LPG, or ammonia. The invention's narrow annular gap at the jet pump nozzle generates a thin but large-area jet due to its large diameter. The large surface area of the annular airflow ensures effective exhaust gas intake into the combustion chamber tube, with only the outer surface of the airflow acting as the intake.
[0030] Within the annular airflow, a flow-free interior space is formed. Gas supply lines and other elements such as a mixing unit for mixing fuel gas with air or an air-exhaust mixture, an ignition device, a burner nozzle, etc., can be routed within this interior space and therefore do not represent any flow obstructions.
[0031] The mixing unit must offer the lowest possible air resistance, which can be achieved, for example, by reducing the number of blades in the mixing unit.
[0032] Preferably, the aforementioned elements are connected to form a burner insert that can be removed as a whole from the combustion chamber tube. For such a burner design with a centrally fed or removable burner insert, the exhaust gas recirculation device designed according to the invention therefore presents neither a structural obstacle nor a functional flow impediment.
[0033] In order to be able to operate the burner with either natural gas or hydrogen, preferably two fuel gas lines are provided, which are only joined together directly at the burner nozzle.
[0034] Preferably, an inner tube adjoining the burner base is provided, containing an inner cavity with a continuous clear opening cross-section. The burner unit, in which the burner nozzle, fuel gas lines, etc., are connected, can be inserted from the burner base through the cavity of the inner tube or pulled out towards the rear, towards the burner base.
[0035] To minimize flow resistance, it is preferably provided that the burner base on one side and the eductor on the other are connected to each other via several spacer elements distributed around the circumference. These very slim spacer elements hardly impede flow, so that the exhaust gas intake opening extends functionally over almost 360°. The eductor, the spacer elements, and the combustion chamber tube or burner base can be manufactured as a single piece using an additive manufacturing process.
[0036] The jet pump integrated into the burner designed according to the invention causes the exhaust gas to recirculate into the combustion air. This changes the composition of the mixture of combustion air, fuel gas and exhaust gas that burns at the burner nozzle.
[0037] In combustion technology, the qualitative terms "rich" and "lean" are commonly used to describe the ratio between oxidizer and fuel. This ratio remains unchanged during exhaust gas recirculation, as only another gas (exhaust gas) is added. However, to describe changes in the properties of the gas mixture during different operating stages, such as start-up, a "lean" fuel gas-air mixture, as defined in the present invention, has a high exhaust gas content and a lower oxygen concentration. Conversely, a "rich" fuel gas-air mixture describes a state in which little to no exhaust gas is recirculated, resulting in a higher oxygen concentration.
[0038] In this sense, a gas mixture of combustion air, fuel gas, and exhaust gas is considered "lean," meaning that the ignition potential of such an unheated mixture is reduced. Therefore, the burner goes out when cold as soon as exhaust gas is recirculated.
[0039] The invention, with further advantageous embodiments, is explained in more detail below with reference to the exemplary embodiments shown in the drawings. The figures show in detail:
[0040] Fig. 1 shows a burner with an exhaust gas recirculation device in perspective view;
[0041] Fig. 2 shows the burner in a perspective sectional view; Fig. 3 shows parts of the burner in longitudinal section;
[0042] Fig. 4 Parts of the burner in perspective view with visualized
[0043] Gaps and openings;
[0044] Fig. 5 shows the exhaust gas recirculation device in an enlarged section of a perspective sectional view and
[0045] Fig. 6 shows another embodiment of a burner in a schematic longitudinal section.
[0046] Figure 1 shows a side view of a burner 100 according to the invention. A burner base 10 comprises a base housing 17 with an air inlet nozzle 13. It is closed at the rear by a closing flange 14. A combustion chamber flange 11 serves to attach the base housing 17 to a furnace wall. A housing section 12 of the base housing 17 projects through the combustion chamber flange 11. A combustion chamber tube 30 connects to the housing section 12 and tapers at its end at a burner mouth cone 31. However, the housing section 12 and the combustion chamber tube 30 do not transition directly into one another, but are connected via an interposed eductor 32, which is held on the housing section 12 by spacer elements 36. The inner diameter of the eductor 32 at the transition to the housing section 12 is larger than the outer diameter of the nozzle ring, which is hidden in Figure 1.In between, an outwardly open exhaust gas intake opening 53 extending over the entire circumference is formed. An inspection tube 49 allows probes and sensors to be inserted from the end flange 14.
[0047] The internal structure of the burner 100 is illustrated by the perspective sectional view in Fig. 2.
[0048] A burner nozzle 41 divides the combustion chamber tube 30 into a combustion chamber 33 and an intermediate chamber 35. The burner nozzle 41 is supplied with fuel gas such as methane and / or hydrogen via fuel gas lines 42, 43. An inner tube 15 is arranged in the base housing 17, such that an air channel 16 is formed between its outer wall and the inner wall of the base housing 17, which terminates at a jet nozzle 20.
[0049] The burner nozzle 41, the fuel gas lines 42, 43, an inner cone 44, an inspection tube 49 and possibly other probes are combined to form a burner insert which can be inserted as a whole into a cavity 18 in the inner tube 15 from the rear side of the base housing 17 after the end flange 14 has been removed.
[0050] The jet nozzle 20 consists of an arrangement of fine nozzle openings extending around the circumference, which together form a driving gap 51. This refers to the opening area – regardless of whether it is an endless, slot-shaped gap or, as in the exemplary embodiment, a plurality of bores.
[0051] The air flowing out of the blowing gap 51 forms a blowing jet that flows past the exhaust gas intake opening 53 at high velocity. This causes exhaust gas to be drawn in from a furnace chamber into which the combustion chamber tube 30 projects. The exhaust gas drawn in at the exhaust gas intake opening 53 mixes with the fresh air exiting the blowing gap 51. The mixture flows through an exhaust gas flow channel 57, which is formed between an inner surface of the outer ductor 32 and an outer surface of an inner flow-guiding element 56. The exhaust gas flow channel 57 begins immediately behind the peripheral exhaust gas intake opening 53.
[0052] The annular gap at the inlet to the exhaust gas flow channel 57 is referred to as the trap gap 52. The flow-guiding element 56 and the exhaust gas flow channel 57 formed by it extend into the intermediate chamber 35, but terminate at a distance from the burner nozzle 41. An outlet gap 54 is formed at the end of the exhaust gas flow channel 57. The base housing 17, the jet nozzle 20, the inner tube 15, and the flow-guiding element 56, along with other elements in the center, are manufactured using an additive manufacturing process and are thus formed as a single piece. To compensate for stresses due to differing thermal expansion, the inner tube 15 transitions into the area of the jet nozzle 20 and the flow-guiding element 56 via a corrugated tube section 19.
[0053] Figure 3 shows a cross-sectional view of the area between the jet nozzle 20 and the burner nozzle 41. This clearly illustrates the relative sizes of the annular gap areas at the beginning and end of the exhaust gas flow channel 57, i.e., the ratio of the area of the trap gap 52 to the area of the outlet gap 54, which in the example shown is 1:2.
[0054] Furthermore, the inclined position of the exhaust gas flow channel 57 is evident. The center line M of the intermediate chamber 35 and the burner nozzle 41 form an angle of 7° with the center line MA of the diverging exhaust gas flow channel 57.
[0055] The inclination and widening of the diverging exhaust gas flow channel 57 result in the outflowing exhaust gas air mixture being directed predominantly onto an outer circumferential area of the burner nozzle 41. The center of the intermediate chamber 35, on the other hand, remains largely unaffected by the exhaust gas air mixture and thus free for the formation of the flame in the center of the burner nozzle 41.
[0056] An ignition insert 48 can be inserted from the burner base 10. For this purpose, a feedthrough tube 45 is integrated into an inner cone 44, which forms the rear boundary of the intermediate chamber 35. A feedthrough tube 46 for the inspection tube 49 is also integrated therein.
[0057] Fig. 5 shows the exhaust gas recirculation device 50 in an enlarged section of a perspective sectional view, particularly to illustrate the relative positions of the jet nozzle 20, the gaps 51, 52 and 54, and the exhaust gas intake opening 53. Fig. 6 shows a schematic longitudinal section of a slightly modified embodiment of a burner 100'. Here, too, a burner base 10' with a base housing 17' with an air inlet nozzle (not visible) is shown.
[0058] In a housing section 12', the base housing 17' initially widens conically and then narrows again after reaching a maximum diameter. A combustion chamber tube 30' connects to the housing section 12', tapering at its end to a burner mouth cone 31'. The housing section 12' and the combustion chamber tube 30' do not merge directly into one another, but are connected by an interposed, funnel-shaped eductor 32', which is held in place on the housing section 12' by spacer elements. An outwardly open exhaust gas intake opening 53', extending around the entire circumference, is formed between the housing section 12' and the eductor 32'.
[0059] A burner nozzle 41' divides the combustion chamber tube 30 into a combustion chamber 33' and an intermediate chamber 35'. The burner nozzle 41' is supplied with fuel gas such as methane and / or hydrogen via fuel gas lines.
[0060] An inner tube 15' is arranged in the base housing 17', such that an air channel 16' is formed between its outer wall and the inner wall of the base housing 17', which terminates at a jet nozzle 20'. This forms a first part of an exhaust gas recirculation device 50'.
[0061] The jet nozzle 20' consists of an arrangement of fine nozzle openings extending around the circumference, which together form a driving gap 51'. The driving gap area is the entire opening area at the driving gap – regardless of whether it is an endless, slot-shaped gap or, as in the exemplary embodiment, a plurality of bores.
[0062] The air flowing out of the blowing gap 5T forms a blowing jet that flows past the exhaust gas intake opening 53' at high velocity. This causes exhaust gas to be drawn in from an outer furnace chamber into which the combustion chamber tube 30' projects. The exhaust gas drawn in at the exhaust gas intake opening 53' mixes with the fresh air exiting the blowing gap 5T or with another oxidizer. The mixture flows through an exhaust gas flow channel 57', which is formed between an inner surface of the outer ductor 32' and an outer surface of an inner flow-guiding element 56'. The exhaust gas flow channel 57' begins immediately behind the peripheral exhaust gas intake opening 53' at the so-called catch gap 52.The inner flow-guiding element 56' and the exhaust gas flow channel 57' formed by it together with the inner surface of the eductor 32' extend into the intermediate chamber 35', but terminate at a distance from the burner nozzle 4T. An outlet gap 54' is formed at the end of the exhaust gas flow channel 57'.
[0063] In contrast to the first embodiment of a burner 100, described with reference to Figures 1 to 5, in this second embodiment of a burner 100' in Figure 6, both the jet nozzle 20' and the subsequent exhaust gas flow channel 57' are inclined at a significantly larger angle of 30° to 90° with respect to the central axis of the combustion chamber tube 30', and the exhaust gas flow channel 57' is no longer directly aligned with the burner nozzle 4T. This large inclination reduces the length of the exhaust gas recirculation device 50' within the burner 100'.
[0064] The flow control element 56' terminates at a central fuel gas line 43'. The intermediate chamber 35' in the combustion chamber tube 30' therefore has an annular cross-section. This annular cross-section is constant. Consequently, the mixture of fresh air and exhaust gas, fed into the burner nozzle from the rear, slows down and becomes more uniform, starting from the outlet gap 54'. Reference symbol:
[0065] 100; 100' burner
[0066] 10; 10' burner base
[0067] 11 Combustion chamber flange
[0068] 12; 12' Housing section
[0069] 13 air intake nozzles
[0070] 14 End flange
[0071] 15; 15' inner tube
[0072] 16; 16' Air duct
[0073] 17; 17' Base case
[0074] 18 Cavity
[0075] 19 Corrugated pipe section
[0076] 20 jet nozzles
[0077] 30; 30' combustion chamber tube
[0078] 31; 31' Brenner mouth cone
[0079] 32; 32' Eductor
[0080] 33; 33' Burner chamber
[0081] 35; 35' Intermediate chamber
[0082] 36 spacer elements
[0083] 41, 41' burner nozzle
[0084] 42, 43 Fuel gas lines
[0085] 44 inner cones
[0086] 45 Feedthrough pipe
[0087] 46 Feedthrough pipe
[0088] 47 inner cones
[0089] 48 Ignition insert
[0090] 49 Inspection tube
[0091] 50; 50' Exhaust gas recirculation device
[0092] 51; 51' drive gap
[0093] 52; 52' Catch gap
[0094] 53; 53' Exhaust intake opening
[0095] 54; 54' Exit gap
[0096] 56; 56' Flow guidance element
[0097] 57; 57' Exhaust gas flow channel
Claims
KPSP 008 WO A4.docx Patent Lawsuit:
1. Burner (100; 100') with an exhaust gas recirculation device (50; 50'), comprising at least: a burner base (10; 10') and a combustion chamber tube (30; 30') in which at least one burner nozzle (41; 41') is positioned, at which at least one fuel gas line (42, 43; 43') opens, wherein the exhaust gas recirculation device (50; 50') is provided with a combustion air-operated jet pump (20) comprising a jet pump nozzle with a propagation gap (51; 5T) and designed to generate an annular propagation jet for drawing in exhaust gases from outside the combustion chamber tube (30; 30'), and the exhaust gas recirculation device (50; 50') comprises, in the flow direction behind the propagation gap (51; 5T), at least: a [missing information] extending over at least a part of the circumference or extending over the exhaust intake opening extending the entire circumference (53;53') and / or an arrangement of several exhaust gas intake openings extending around the circumference, and / or an exhaust gas intake opening routed inwards into the combustion chamber tube (30; 30') via a flow deflection element, characterized in that downstream of the friction gap (51; 5T) and the exhaust gas intake opening(s) (53; 53') an exhaust gas air mixture flow channel (57; 57') is formed between an inner surface of an external eductor (32; 32') and an outer surface of an internal flow guide element (56; 56'), which extends longitudinally between a trapping gap (52; 52') and an outlet gap (54; 54'), and that the inclinations of the surfaces of the flow guide element (56; 56') and the eductor (32; 32') to each other are selected such that the The ratio of the area of the entire trapping gap (52; 52') to the area of the entire exit gap (54; 54') is between 1 :7 and less than 1 :
1. KPSP 008 WO A4.docx 2. Burner (100; 100') according to claim 1 , characterized in that the area of the driving gap (51 ; 5T) is smaller than or equal to the area of the trapping gap (52; 52') and this is smaller than or equal to the area of the exit gap (54; 54').
3. Burner (100; 100') according to claim 2, characterized in that the ratio of the area of the exhaust gas intake opening (53; 53') to the area of the trap gap (52; 52') is between 1 :3 and 3:
1.
4. Burner (100; 100') according to claim 3, characterized in that the width of the exhaust gas intake opening (53; 53') is 6 mm to 15 mm.
5. Burner (100; 100') according to claim 3 or 4, characterized in that the ratio of the area of the drive gap (51 ;51') to the area of the catch gap (52;52') is between 1 :20 and 10:
20.
6. Burner (100; 100') according to one of the preceding claims, characterized in that the outlet gap (54; 54') is arranged at a distance L2>0 to the burner nozzle (41 ; 41 ').
7. Burner (100; 100') according to claim 6, characterized in that the exhaust gas flow channel (57; 57') between the trapping gap (52; 52') and the outlet gap (54; 54') has a length L1 and terminates in the combustion chamber tube (30; 30') at a distance L2 from the burner nozzle (41), wherein the ratio of L2 : L1 is > 0 to 2:
1.
8. Burner (100; 100') according to one of the preceding claims, characterized in that the opening of the drive gap (51 ; 51 ') is formed within the cross-section of the trap gap (52; 52').
9. Burner (100; 100') according to one of the preceding claims, characterized in that the drive gap (51 ; 5T) and / or the exhaust gas intake opening (53; 53') and / or the catch gap (52; 52') is / are each annular in shape.
10. Burner (100; 100') according to one of the preceding claims, characterized in that the drive gap (51; 5T) and / or the exhaust gas intake opening KPSP 008 WO A4.docx (53; 53') and / or the trapping gap (52; 52') each has a meandering course.
11. Burner (100; 100') according to one of the preceding claims, characterized in that the drive gap (51; 51') and / or the exhaust gas intake opening (53; 53') and / or the catch gap (52; 52') each run in an annular shape endlessly, i.e. without interruptions.
12. Burner (100; 100') according to one of the preceding claims 1 to 10, characterized in that the drive gap (51; 51') and / or the exhaust gas intake opening (53; 53') is (are) each formed by an arrangement of several openings arranged on a circumferential line, wherein the area of the drive gap (51; 5T) and / or the area of the exhaust gas intake opening (53; 53') and / or the area of the intake gap (52; 52') is each defined by the sum of all clear areas that functionally define the respective gap.
13. Burner (100; 100') according to one of the preceding claims, characterized in that the volume of the exhaust gas-air mixture flowing at and through the burner nozzle is limited by the minimum cross-section of the nozzle flow area between the combustion chamber tube and the burner nozzle, wherein the ratio between the outlet area and the minimum nozzle flow area is between 7:20 and 18:
20.
14. Burner (100; 100') according to one of the preceding claims, characterized in that the jet direction of the fresh air jet entering through the drive gap (51; 5T) is aligned with the center line of the capture gap (52; 52').