WO2015135679A1

WO2015135679A1 - Multistage surface burner

Info

Publication number: WO2015135679A1
Application number: PCT/EP2015/051536
Authority: WO
Inventors: Ulrich Dreizler
Original assignee: Ulrich Dreizler
Priority date: 2014-03-11
Filing date: 2015-01-27
Publication date: 2015-09-17
Also published as: DE202014101097U1; EP3117146A1; EP3117146B1

Abstract

The invention relates to a burner (13) with surface combustion, having a first and at least one additional burner zone (34, 35), each of which has a feed (29, 37) for a fuel/air mixture in a combustion zone (51) and each of which has a woven membrane (49) for each burner zone (34, 35), the combustion zone (51) adjoining said fabric membrane. The burner also comprises a flashback barrier (48) which is arranged upstream of the woven membrane (49) and at a distance to the fabric membrane. Each burner zone (34, 35) has a separate feed (29, 37) for the fuel/air mixture, and each burner zone (34, 35) has a flame matrix (52), which are aligned in the same direction, in the combustion zones (51).

Description

[Designation of the invention prepared by ISA according to Rule 37.2] MULTI-STAGE SURFACE BURNER

The invention includes a burner with a surface combustion, which comprises a first and at least one further burner zone.

WO 2006/019279 A1 discloses a burner with a surface combustion, which comprises a housing which receives a fan at one end and supplies a fuel-air mixture to burner zones at the opposite end downstream. The burner zones each include a plate having a plurality of bores secured to the housing. These are assigned upstream of another mixing plate with additional holes. By the fan combustion air is supplied. Downstream of the supply of combustion air, individual feeds for the fuel are provided on the housing. In the housing, fuel and air are mixed at the mixing plate and supplied to the respective burner zone, wherein upstream of each burner zone adjacent partition walls are provided which extend to the fuel supply to supply the burner zones. However, all burner zones are supplied with the same air volume flow provided by the blower.

From WO 02/075211 A1, a gas burner is known, which comprises three burner zones, to each of which a gas-air mixture is supplied by separate feeds. These three burner zones are fed independently of each other, the gas-air mixture for combustion. The combustion surface or the combustion zone is formed by a frusto-conical lateral surface which comprises a first and a second burner zone. At the narrow end face of the frustoconical surface, the third burner zone is formed by a hemispherical surface. The flames exiting laterally on the lateral surface of the burner surface are inclined with respect to the exit plane by almost 90 ° in the direction of the center of the combustion chamber, which lies downstream of the gas feed. Due to the succession of burner zones, a very long combustion chamber is required.

Furthermore, a gas burner is known from WO 2010/044931 A1, which is used for the heating of water, which flows through a heat exchanger in a combustion chamber of the gas burner. This gas burner has a first and second burner zone, wherein the first burner zone comprises a combustion zone oriented radially to the longitudinal axis of the burner. Within the first burner zone, a gas-air mixture is supplied to a second burner zone, which comprises both a radially aligned combustion zone corresponding to the first burner zone and a further axially aligned combustion zone, which together form the second burner zone. For this purpose, a structurally complex structure is provided.

The invention has for its object to provide a burner with a surface system, which is constructed mehrzonig and a small space for arrangement in a burner plate or a burner and an efficient control includes and to provide a heat generator, which is physically small, but a high heat output allows.

This object is achieved by a burner in which each burner zone is supplied by a separate supply with a fuel-air mixture and the burner zones have a aligned in the same direction flame matrix. As a result, on the one hand, low-profile burner zones can be created in the installation depth, so that a plurality of burner zones can be arranged next to one another, which, on the other hand, can be controlled by the respective separate supply of fuel-air mixtures in accordance with the desired operating mode.

Preferably, the flame matrix of each burner zone is aligned axially with the flow direction of the fuel-air mixture between the flame arrestor and the tissue membrane. As a result, the flame matrix is perpendicular to the surface of the tissue membrane, so that a free exit of the individual flame from the tissue membrane without tilting or deflection is possible, whereby an increased efficiency in the combustion and thus increased efficiency in the heating of the burner chamber is made possible.

The respective tissue membrane of the burner zone is arranged according to a preferred embodiment in a same plane. As a result, a large-area burner can be subdivided into several burner zones with different or even the same area proportions as well as a separate control. Alternatively, the individual tissue membranes of each associated burner zones may be provided offset parallel to each other. This is preferably then provided in order to assign the individual burner zones to one another in a structurally compact manner.

The respective tissue membrane of the associated burner zones preferably has a maximum offset when arranged with a parallel offset from one another which is equal to or less than the length of a flame root of the flame matrix. As a result, a homogeneous flame matrix extending over all the tissue membranes of the burner zones can be achieved.

The length of the flame root of the respective flame matrix is preferably less than 100 mm and the longest at full load.

According to a first embodiment, a blower is provided for each burner zone. Thereby, a specific control and supply of the fuel-air mixture for each burner zone can be achieved, whereby the length of the flame root can be determined.

Alternatively, a common fan for supplying the fuel-air mixture and at least one of at least two leading to the respective burner zone supply a control valve may be provided for all burner zones of the burner. As a result, multiple burner zones can be controlled with only one common blower and be supplied by driving the control valve or control flaps with the fuel-air mixture.

According to a preferred embodiment, at least one ignition electrode and / or at least one monitoring electrode are assigned to the first burner zone to be ignited. For example, the first burner zone may be formed as a preliminary stage, which is first ignited and monitored in order to form a flame matrix in the combustion zone. Due to the second and / or further burner zone arranged adjacently thereto, this second or further burner zone can be switched on as a function of the feed of the fuel-air mixture, the flame matrix of the first burner zone being fed to the fuel-air / gas mixture for a second and / or further burner zone. or another adjacent burner zone and forms with this a common flame matrix.

According to a first embodiment of the combustion zone of the burner, a first burner zone is completely surrounded by the second and / or at least one further burner zone. This arrangement can also be reversed. As a result, it is possible to form, for example, two burner zones arranged concentrically to one another, which are usually activated in such a way that the smaller of the two zones is first ignited.

A further alternative embodiment of the combustion zone of the burner provides that the first and at least one further burner zone each have the same area fraction. Alternatively, the first burner zone may also be formed in the area deviating from the second or further burner zone, with the first burner zone preferably being smaller than the second burner zone in the case of two burner zones. Depending on the overall control ratio of, for example, the first and second burner stage, the size ratio of the respective burner zone is set. This depends on the heat generator to be fired and the downstream heat process. The total control ratio can be determined from the sum of the maximum power of the first and second burner zones in relation to the minimum power of the first burner zone. The same applies to more than two burner zones.

A further preferred embodiment of the invention provides a common contact line or a common contact point of the respective flame matrix between the first and at least one further burner zone. The flames of the flame matrix expand to the end of the respective flame in the flow direction of the fuel-air mixture, so that an expansion of the flame matrix is also given in the edge region of the combustion zone, whereby a simplified ignition of the adjacent combustion zone of another burner zone is made possible.

The first and at least one further burner zone preferably have a circular, rectangular or square geometry for forming a combustion zone. This allows an adaptation to the installation conditions are made possible. For example, a circular or square geometry may be provided for a cylindrical burner space. Furthermore, an oblong-rectangular burner with a first and a second burner zone can be formed and used for strip-shaped and elongate heating zones.

Furthermore, the second or further burner zone preferably has two to seven times the area fraction of the first burner zone. As a result, the first burner zone forms a preliminary stage and the second burner zone forms, for example, a main stage, preferably together with the precursor, for heating the combustion chamber.

A further preferred embodiment of the invention provides that the fuel-air mixture is mixed before the at least one blower and fed via the blower, the mixture of at least one burner zone. This is called a so-called premix burner. Alternatively, after the at least one blower, the fuel-air mixture can be mixed and then fed to the at least one burner zone. Such an embodiment is referred to as a postmix burner.

A preferred embodiment of the burner with the first and at least one further burner zone provides that they are arranged in a common burner head, so that the first and at least one further burner zone are arranged together on a burner plate to the burner chamber, which on a burner housing for closing the Burner space is attachable.

As an alternative to this embodiment, the first and at least one further burner zone can each be formed by a separate combustion head with a respective housing, which are arranged adjacent or adjacent to one another in a burner plate.

The object underlying the invention is further achieved by a heat generator, in which a burner can be used according to one of the embodiments described above. Preferably, the heat generator for heating a liquid, vapor or gaseous medium may be provided, in which preferably a supply line into a burner chamber of the housing of the heat generator leads to heat the medium flowing through the conduit. In particular, the conduit is part of a heat exchanger to heat, for example, water. Such a heat generator with a burner allows a small-sized arrangement with a high heat output.

The invention and further advantageous embodiments and developments thereof are described in more detail below with reference to the examples shown in the drawings and explained. The features to be taken from the description and the drawings can be applied individually according to the invention individually or in combination in any combination. Show it:

FIG. 1 shows a schematic sectional view of a burner with a first and a second burner zone,

FIG. 2 shows a diagrammatically enlarged view of a burner head of the burner according to FIG. 1 in a sectional illustration,

FIG. 3 shows a schematic side view of the combustion head according to FIG. 2,

FIG. 4 shows a schematic view of a first and a second burner zone, which is offset relative to one another, according to FIG. 2,

FIGS. 5a and 5b show schematic views of alternative embodiments for actuating the combustion head according to FIG. 2,

FIGS. 6a to 6e show schematic views of alternative embodiments of multi-stage combustion heads,

Figure 7 is a schematic sectional view of an alternative embodiment of the first and second burner zones to Figure 1 and

8 shows a schematic view of the burner zones according to FIG. 7.

FIG. 1 shows a schematic sectional view of a burner 13 on a heat generator 11 with a burner chamber 12, into which a heat exchanger or a liquid medium-carrying line 14 protrudes in order to heat the liquid medium guided through the line 14 and to dissipate the thermal energy of the flame , The heat transfer medium may also be vapor or gaseous. The heat generator 11 comprises a housing 16, which has at an end face an opening 17 with a pipe 18 for the discharge of hot combustion gases. Opposite lying the burner chamber 12 is closed by a burner plate 21 which receives a burner 13 with a burner head 23 with a fan 24. Such a burner 13 can be operated as a gas appliance in accordance with EN676 "Gas Blower Burner". Likewise, an operation according to EN746-2 on thermal processing plants in the field of industry and commerce is possible. A delineation of the respective areas of application is described in the corresponding standards under "area of application".

According to a first embodiment, air is supplied to the blower 24 via an air supply line 26. Furthermore, a fuel line 27 leads to the blower 24, wherein a certain amount of fuel is supplied to the blower 24 via a solenoid valve 28. This fan 24 preferably has a not-shown fan wheel, so that after the blower 24, a fuel-air mixture is generated and fed via a feed 29 to the burner head 23. Alternatively, a fuel-air mixture can be supplied to the blower 24 already.

The control of the solenoid valve 28 for determining the amount of supplied fuel via a control device 40, which can monitor and control the activation of the entire combustion process. The burner head 23 further comprises at least one ignition electrode 31 and at least one monitoring electrode 32, which are shown in Figure 1 only schematically and also connected to the controller 40 to forward data to the controller 40 or to drive the ignition electrode 31 to ignite the burner head 24.

The burner head 23 according to FIG. 1 is constructed in two stages by way of example and comprises a first burner zone 34 and a second burner zone 35. Each of these

burner zones

34, 35 can be individually controlled continuously from the smallest to the largest power. The second burner zone 35 is connected to the second burner zone 35, for example, by means of a feed 37 leading away from the housing 36 of the first burner zone 34. The feeder 37 may also branch off from the feeder 24 coming from the fan 24. The supply 37 comprises a control flap 38, which in turn is in communication with the control device 40 and can be controlled via it.

The structure of this multi-zone burner head 23 of the burner 11 will be described in more detail in the following Figures 2 and 3.

The burner head 23 according to the embodiment comprises a cylindrical housing 36 having a bottom 41 to which the feeder 29 is connected, through which the fuel-air mixture is supplied via the blower 24 of the first burner zone 34. Within the housing 34, a housing partition wall 43 is arranged to form the first and

second burner zone

34, 35, which forms a housing 44 for the first burner zone 34 together with the associated portion of the bottom 41. A housing 45 for the second burner zone 35 is formed by the housing partition wall 43 of the housing 44 and an outer wall 46 of the housing 34 of the burner head 23. In this outer wall 46, the feed opens 37 for supplying the fuel-air mixture. Alternatively, this feed can also be connected to the bottom 41 of the housing 45. Alternatively, the supply 37 may also be arranged on the bottom 41 of the housing 45. The housing 44 of the first burner zone 34 and the housing 45 of the second burner zone 35 are nested and combined with each other so that the second housing 45 concentrically surrounds the housing 44. Preferably, a common bottom 41 for the

housing

44, 45 is provided. Alternatively, the bottoms of the

housings

44, 45 may be offset from each other.

The first burner zone 34 includes a flashback barrier 48 as viewed from the bottom 41 and as viewed in the direction of flow of the fuel-air mixture and spaced therefrom and tissue membrane 49. The tissue membrane 49 may be spaced from the flashback barrier 48 by spacers or a wall section or the like. Downstream of the tissue membrane 49, a combustion zone 51 is provided within which a flame matrix 52 is formed, wherein the combustion zone 51 is delimited in the radial direction by a delimiting element 54.

The first burner zone 34 includes, for example, an ignition electrode 31 and one or more monitoring electrodes 32, which are arranged, for example, in the middle of the first burner zone 34 or in the housing 44 of the first burner zone. Due to this central arrangement of the ignition electrode 31 and monitoring electrode 32, the feed 29 of the fuel-air mixture is formed on the housing 44 by a fork-shaped connection 56 which covers, for example, three openings 57 in the bottom 41. The at least one ignition electrode 31 and / or monitoring electrode 32 can also be arranged in an edge region in the housing 44 of the first burner zone 34, so that a central or in the remaining area arranged in the bottom 41 supply of the fuel-air mixture is possible.

The second burner zone 35 also includes a flashback barrier 48 as seen in the flow direction and, spaced therefrom, a tissue membrane 49 to form an annular combustion zone 51. Preferably, again delimiting elements 54 are provided in the housing 45.

The limiting element 54 is designed to hold down the tissue membrane 49 to the spacer which positions the tissue membrane 49 at a predetermined distance from the flame arrester 48. On the other hand, the limiting element 54 is designed such that starting from the operation of the burner head 23 with the first burner zone 34 by a switch of the second burner zone 35 ignition of the flame matrix 52 of the second burner zone 35 due to the flame matrix 52 in the first burner zone 34 is made possible. The individual flames 59 emerging from the fabric membrane 49 expand at the end of the individual flames in the direction of flow, so that expansion of the flame matrix 52 in the edge region of the burner zone 34 is provided and if the fuel-air mixture is supplied via the adjacent burner zone 35 an automatic ignition of the burner zone 51 of the adjacent burner zone takes place.

The arrangement and design of the burner head 23 with a tissue membrane 49 spaced from the flame arrestor 49 enables the formation of a cool flame root, in particular when using a tissue membrane 49 according to WO 2012/065582, to which reference is made in its entirety.

FIG. 4 schematically shows the arrangement of the tissue membrane 49 of the first burner zone 34 and of the second burner zone 35 according to FIG. 2, these being aligned with a parallel offset a relative to one another.

At each fabric membrane 49, a flame matrix 52 is formed in the region of the combustion zone 51, which is composed of individual flames 59 and holding flames 60 arranged between them, the individual flames 59 protruding from the holding flames 60. The parallel offset between the tissue membrane 49 of the first burner zone 44 and the tissue membrane 49 of the second burner zone 45 corresponds at most to the flame root of the individual flame 59. The maximum offset a also applies to further tissue membranes 49 which are provided in further burner zones in multizone burners 11.

"Flame root" is understood to mean a zone of the individual flames 59 which keeps this individual flame 59 stabilized, so that it does not lift off the tissue membrane 49 or can go out. In the flame root of the fuel and oxygen is only partially ignited and is still partially separated. Only at the end of the flame root in the direction of flow of the fuel-air mixture, the exothermic reaction is completely started, which is then completely completed in the combustion of the flames. Consequently, in the flame root, the ignition of the combustion reaction - that is, the oxidation of a combustible material with oxygen, whereby the flame is formed - not yet completed. Unburned components of oxygen and combustible material may still be present. The flame root can be visually recognized in a premixed, stoichiometric fuel-air mixture as a flame on its blue core color, which is more visible than the rest of the flame.

In the schematic arrangement shown in Figure 4, the offset a may also be zero, that is, the tissue membrane 49 of the first burner zone 34 and that of the second burner zone 35 are arranged in a same plane.

FIGS. 5a and 5b show schematic views showing an alternative embodiment with regard to the supply of the fuel-air mixture to the burner head 23 of the burner 11 to FIGS. 1 to 3. FIG. 5a differs from the supply of the fuel-air mixture of FIG. 1 in that a branch 62 is provided in the supply line 29, which branches the volume flow fed through the blower 16, so that in each case a separate supply for the first and

second fuel stage

34, 35 is provided. Each

feeder

29, 37 comprises a separate control flap 38, which can each be activated separately from the control device 40 in order to control the respective volume flow.

FIG. 5b shows a feed for a fuel-air mixture to the burner head 23, in which each

burner zone

34, 35 is connected in each case to a

feed line

29, 37 to which a blower 24 is connected, so that each

burner zone

34, 35 is independent from the

other burner zone

35, 34 can be filled with a fuel-air mixture, so that the mixtures can also differ from each other.

FIGS. 6a to 6e show diagrammatic views from above of a burner 11 with, for example, two

burner zones

34, 35, which have different arrangements and geometries. It is understood that instead of two burner zones, it is also possible to provide a plurality of burner zones which have an analogous structure.

FIG. 6a shows an end view of the burner head 23 according to FIG. 2 with a round combustion zone 51, whereby FIG. 6a deviates in that the at least one ignition electrode 31 and / or monitoring electrode 32 is not centered but off-center in the tissue membrane 49 of the first burner zone 34 is arranged. Preferably, the second burner zone 35 comprises a multiple of the first burner zone 34 with respect to their surfaces. The second burner zone 35 completely surrounds the first burner zone 34. These have a common contact line 64 of the respective flame matrix 52. Along this contact line 64, the flame matrix 52 of the first burner zone 34 is skipped over to the second burner zone 35 when the second burner zone 35 is switched on. In multi-zone burners, a third burner zone can completely surround the second burner zone or the second and third burner zone can jointly surround the first burner zone. Alternatively, the first burner zone may also be formed in two or more zones and surrounded by an annular burner zone in analogy to the illustrated two-stage burner zone.

FIG. 6b shows an alternative embodiment to FIG. 6a. In this embodiment, the first and

second burner zones

34, 35 have equal areas, which are separated by the contact line 64, in each of which a combustion zone 51 with a semicircle for the first and

second burner zones

34, 35 is formed. Alternatively, here also the first burner zone 34 of the combustion zone 51 may comprise a circular arc segment and the second burner zone 35 occupy the remaining area

FIG. 6c shows an alternative geometric configuration of the combustion zone 51 to FIG. 6b, in that the first and

second burner zones

34, 35 are square, but with the same area division. Alternatively, in FIG. 6 c, a rectangular arrangement may also be provided.

With regard to an equal area distribution between the first and

second burner zones

34, 35, according to FIG. 6 d, a division with respect to a square combustion zone 51 can also take place via a diagonal contact line 64.

FIG. 6 e shows a further alternative embodiment, which comprises a flat-rectangular combustion zone 51 of the first and

second burner zones

34, 35, which comprise a common contact line 64. Such an embodiment is preferably provided in so-called ingot burners whose length comprises a multiple of the width.

Further geometric configurations and divisions with respect to the respective combustion zone 51 of the first and

second burner zones

34, 35 are also possible and conceivable. The same applies to three or more burner zones of a burner head 23, whose surface portions, for example, can change in predetermined stages, but which form a common surface with respect to a combustion zone 51 of the burner 11.

FIG. 7 shows an alternative embodiment to FIG. The structure of the burner 13 corresponds to that in Figure 1. Notwithstanding, in the embodiment in Figure 7 to Figure 1 provided that two separate burner heads 23 are associated with each other and received in a burner plate 21, wherein a burner head 23, a first burner zone 34 and a second Burner head, the burner zone 35 forms, which are preferably formed differently in size in the area of the combustion zone 51, as can be seen from the end view in Figure 8. In this case, the second burner zone 35 is preferably designed to be at least three times larger, preferably five times larger, than the first burner zone. Each burner head 23 is supplied via a blower 24 with a fuel-air mixture. Each burner head 23 has an analogous construction to the first burner zone 34 or second burner zone 35. In a housing of the burner head 23 downstream of the supply of the fuel-air mixture, a flame arrester and at a distance therefrom a tissue membrane 49 is provided, so that on one exit side of the tissue membrane in a combustion zone 51, a flame matrix 52 can form, the individual flames 59 and the holding flame 60 are aligned perpendicular to the plane of the tissue membrane 49. The individual flames 59 are thus aligned in the flow direction within the combustion zone 51. The housings 24 of the burner heads 23 for the first and

second burner zones

34, 35 may, for example, abut each other at a contact point 65 or have only a small spacing, and the at least one ignition electrode 31 and / or monitor electrode 32 may be positioned in a gusset resulting therefrom that a central or eccentric arrangement of the ignition electrode 31 and / or monitoring electrode 32 in the first burner zone 34 is not required. However, this can also be chosen. This makes it possible to skip the flame matrix 52 out of the first burner zone 34 into the second burner zone 35 when the burner 13 is connected to the second burner zone 35.

In the arrangement shown in FIG. 8, the ignition electrode 31 and monitoring electrode 32 can be assigned to the first burner zone 34 and a further monitoring electrode 32 can be assigned to the second burner zone 35. Alternatively, the ignition electrode 31 and / or monitoring electrode 32 may also be assigned separately from one another corresponding to the first and / or

second burner zones

34, 35.

The two burner heads 23 are adjusted with respect to the orientation of the tissue membranes 49 such that they lie in one plane or have a maximum offset a corresponding to FIG.

Claims

A burner (13) having a surface combustion comprising a first and at least one further burner zone (34, 35), each having a feed (29, 37) for a fuel-air mixture in a combustion zone (51) and for each Burner zone (34, 35) comprise a tissue membrane (49), which is followed by the combustion zone (51) and each having a flame arrester (48), which is upstream of the tissue membrane (49) and spaced apart, characterized in that each Burner zone (34, 35) each having a separate feed (29, 37) for the fuel-air mixture and the burner zone (34, 35) in the combustion zone (51) in the same direction aligned flame matrix (52).
Burner according to claim 1, characterized in that the flame matrix (52) of the burner zones (34, 35) is aligned axially with respect to the flow direction between the flame arrester (48) and the fabric membrane (49).
Burner according to claim 1 or 2, characterized in that the respective tissue membrane (49) of the burner zones (34, 35) are aligned in the same plane or parallel offset from one another.
Burner according to claim 3, characterized in that the tissue membranes (49) of the burner zones (34, 35) have a maximum offset (a) equal to or less than the length of the flame root of the flame matrix (52).
Burner according to claim 4, characterized in that the length of the flame root is less than 100 mm.
Burner according to one of the preceding claims, characterized in that a respective blower (24) is provided for each burner zone (34, 35).
Burner according to one of claims 1 to 5, characterized in that for the burner zones (34, 35) has a common fan (24) for supplying the fuel-air mixture and in at least one feed (29, 37) to the burner zones (34 , 35) a control flap (38) is provided.
Burner according to one of the preceding claims, characterized in that at least one ignition electrode (31) and / or at least one monitoring electrode (32) is associated or integrated with the first burner zone (34; 35) to be ignited.
Burner according to one of the preceding claims, characterized in that the first burner zone (34) is completely surrounded by the at least one further burner zone (35).
Burner according to one of the preceding claims, characterized in that the first burner zone (34) and the at least one further burner zone (35) each have the same area ratio.
Burner according to one of the preceding claims, characterized in that a common contact line (64) or a common contact point (65) of the adjacent flame matrices (52) is provided between the first and at least one further burner zone (34, 35).
Burner according to one of the preceding claims, characterized in that at least one first and at least one further burner zone (35) have a circular, rectangular or square combustion zone (51).
Burner according to one of claims 1 to 9, characterized in that the at least one further burner zone (35) has at least twice, preferably two to seven times, the area proportion of the first burner zone (34).
Burner according to one of the preceding claims, characterized in that the fuel-air mixture before the at least one blower (24) mixed or after the at least one blower (24) mixed and the at least one burner stage (34, 35) is supplied.
Burner according to one of the preceding claims, characterized in that the first and at least one further burner zone (34, 35) in a common burner head (23) are arranged.
Burner according to one of claims 1 to 13, characterized in that the first burner zone (34) and at least one further burner zone (35) in each case by a separate burner head (23) is formed.
Heat generator with a housing (16) which surrounds a burner chamber (12) which can be closed by a burner plate (21), characterized in that a burner (13) according to one of claims 1 to 16 can be arranged on the burner plate (21) ,