EP0704656B1 - Burner head element - Google Patents

Abstract

The cut-out portions (10,12) extend in the length wise direction of the insert, and in which the fuel is discharged. They end at different distances from the fuel-discharge head (4). The cut out portions can extend for different lengths in the lengthwise direction and/or for different distances inwards towards the insert axis. The front and/or rear cut-out portions can be joined together by a ring portion running in the peripheral direction. There can be a baffle (2) upstream of the cut-out portions and of cylindrical or funnel shape, in the latter case widening in the flow direction.

Description

The invention relates to an insert for a device for igniting or burning of fuels, in particular a heating device according to the preamble of claim 1, such as one of the FR-A-1 370 708 is known.

Furthermore, the present invention relates to a device for igniting or Burning fuels, especially a heater according to the Preamble of claim 8, corresponding to FR-A-1 370 708.

Corresponding inserts or devices, such as mixed ignition devices with an oil atomization device or a gas combustion device with a surrounding this oil atomization device or gas combustion device Pipe are well known. The pipe in question points around its circumference extending annular constriction sections or widening sections. Based on this construction, the temperature distribution within the tube is that can also be referred to as a flame tube, based on the entire diameter, equal.

Because of this known, generally used version of the generic Device or the generic use occur locally in a heating device very high temperatures leading to a comparatively very high Share nitrogen oxides in the combustion gas or in the exhaust gas.

FR-A-1 370 708 describes an insert for a device for ignition or Burning fuels, in particular for a heating device, is known. This known use is in the direction of fuel ejection, i.e. in the direction of the flame, provided with several sections that sit on a cylindrical base body. These sections are twisted to each other so that a swirl the gases occur within the associated burner. So this is known Use designed as a swirl body and is intended to swirl the gases within cause the burner to face inwards, which is why the twisted Sections or slats are provided. This is intended to ensure that the soot number can be reduced to near zero, while the No reduction in the nitrogen oxide content in the combustion gas or in the exhaust gas is addressed.

It is the object of the present invention, an insert or a device propose that when burning fuel to a lesser extent of nitrogen oxides in the combustion gas or in the exhaust gas.

This object is achieved by using the features listed in claim 1 solved.

A device with the features of claim 8 solves that of the present Object underlying the invention equally.

Advantageous refinements according to the invention are given in the subclaims Are defined.

The advantages to be achieved according to the invention are based on the fact that the use and the Device for igniting or burning fuels in the area of use which has or in the course of the fuel ejection direction at least one bluff body, and each group of sections at least substantially equally inward Cylinder axis of the base body comprises curved sections, each section group ends at a diameter range.

This results in a narrowing of the cross section in a first region generated of the insert, which leads to the fact that supplied combustion gas or air is led together with hot gases to the inside of the flame, with a lack of oxygen is present. Due to this lack of oxygen, the flame core temperature is reduced and the proportion of thermal nitrogen oxides is effectively reduced.

A further part of the required combustion gas or the required combustion air is supplied through further sections formed at a greater distance from the fuel ejection device, so that the flame is supplied with the required combustion oxygen in portions over an enlarged distance. As a result, the amount of air or oxygen required for complete and effective combustion is supplied, but over a range that is lengthened by technical means, so that the combustion range is extended. As a result, the maximum temperatures that occur are reduced, and consequently the quantities of thermal nitrogen oxides (NO, NO _x ) that occur can be reduced.

It is also important that the tapering of the insert is not closed Cones are formed. This would cause the flame speed in Area of the first constriction increase so much that the flame speed would be greater than the ignition speed of the fuel-air mixture. This would lead to the flame from the fuel ejection device or stands out from the desired area and the combustion is hardly in one desirable scope could be regulated.

Through an insert designed according to the invention or an insert according to the invention trained device it is possible to sum the resulting gas flow velocities to shrink, although the air speed in the Area of the first constriction formed by at least some of the sections is quite high. This is because the speed of the air or Combustion gases where the sections or lamellae leave openings, is greatly reduced. The high flow rate cannot cope with this react the flame so that the flame is in the desired and if necessary optimum range and does not tend to move away from that optimal area to solve.

Advantageously, the sections should be in the fuel ejection direction Longitudinal direction of the fuel ejection device at least partially be of different lengths, the relevant sections preferably in Groups are essentially the same length. It has proven to be particularly advantageous proven if the respective sections are of equal length in two stages and thus be divided into two groups. If necessary, there could be more Groups, e.g. a third group or level of essentially the same Sections or fins may be provided, possibly with larger heating devices.

Leave groups or levels of different lengths with the relevant sections are also adjusted in that the sections are at least partially different are oriented far inwards or are curved inwards.

Very significant advantages can be achieved in that the different Distance from portions ending at the fuel ejector a circumferential extent are connected to each other.

In this case, either the sections ending at the front can be Cylinder or the like can be combined or the rear sections can be summarized accordingly.

Are the sections or slats by means of such a ring or cylinder or the like summarized, this results in a stabilization of the sections or slats, so that the slats through during operation thermal influences are neither deflected nor moved in the positions can. In addition, this training ensures that the air outlet flows be separated. Thereby, the air outlet flow passes through the least wide sections or lamellae extending to the front is produced, directed inwards and the air outlet flow through the most advanced slats is generated, is directed to the outside.

A particularly advantageous arrangement results from the fact that the extension or the ring on the radially inward edge of the respective sections is arranged. The slats or sections are advantageously in two groups ending at different distances from the fuel ejection device divided.

If the extension or the ring is arranged on the shorter group of plates, then the separation of the air outlet flows can be even more favorable. It can the outer air of the short sections or lamellas better with the inner air of the most forwardly extending sections or slats.

All groups of slats of the same length have a corresponding extension or a corresponding ring or cylinder, so the mentioned advantages for certain applications.

A combination of different lengths and different lengths is particularly advantageous sections oriented far inwards, which may have groupings with can result in different levels.

The individual sections can be continuous and / or continuous or be differently shaped or oriented inward. Advantageously is used in the area in front of or in the course of the fuel ejection device, hereinafter referred to as oil or gas injection nozzle, or "nozzle" for short, arranged at least one bluff body. This bluff body advantageously has in continuation of the fuel ejection device or the longitudinal direction the nozzle has a substantially central opening through which the fuel or a flame corresponding to it can pass through. Through this also known as baffle block is ensured that in A pressure increase in the area in front of the baffle plate and in the area behind the baffle plate a decrease in pressure occurs in connection with the invention leads to the combustion area further apart by the additional negative pressure, which is also suitable for the flame at a predetermined Point to keep the combustion area further apart is, whereby the maximum occurring temperatures are further reduced can, which can further reduce the generation of nitrogen oxides.

In this case, there must advantageously be a sufficient one between the bluff body and the insert Stay clear to supply a sufficient amount of combustion gas or combustion air.

The bluff body can advantageously be in the fuel ejection direction or in The longitudinal direction of extension of the fuel ejection device extends cylindrical or conical or funnel-like, preferably widening Have range. In this way, the said negative pressure zone can be more pronounced, which leads to the flame in the area of the bluff or the Baffle plate is held. The effects mentioned can still be achieved reinforce that the cylindrical or conical or funnel-like area at least partially extending to different extents in the fuel ejection direction Has partial areas. This can be used to make further improvements, for example achieve that the bluff body around the substantially central opening if necessary has recesses connected to this central opening.

Due to the above-mentioned designs of the bluff body, which however, any combination can be used on the one hand fix the flame at a certain point in the combustion chamber and on the other hand pull apart such that the peak temperature in the flame is reduced, whereby the proportion of nitrogen oxide in the exhaust gas can be reduced.

Instead of one insert designed according to the invention, several can also be used Inserts that are similar or equally designed are used. One insert can surround the other insert or one insert of several other missions. It is also preferable if there are free spaces or channels between the individual inserts through which Combustion gas or combustion air can be supplied.

Experiments have shown that it is particularly advantageous if the sections of the Insert designed according to the invention in at least one, preferably two Levels are divided, and the sections assigned to the respective levels in are essentially the same. So a first stage can be made up of shorter ones a predetermined dimension inwardly curved sections or slats consist, while the second stage of longer, also curved inwards Sections or slats can exist. This will make the area over which Combustion air is supplied across the flame. In addition, as already pointed out, a first area with an oxygen deficiency generates, which leads to the peak temperatures in the flame can be reduced, which means that less nitrogen oxides are generated during combustion.

Experiments have shown that it is particularly advantageous if the distance between the rearmost front edge of the bluff body in the direction of fuel ejection or in the longitudinal direction of the fuel ejection device, and the in the longitudinal direction at the foremost end, each with a comparable design Sections or respective steps, approximately equal to 0 to approximately 0.5 times the diameter D of the stake.

Furthermore, extensive tests have shown that the diameter of the fuel in the direction of fuel ejection or in the longitudinal direction of the fuel ejection device front end of the sections or slats, each approximately are the same, or the sections or lamellae of the first stage, for example equal to 0.7 to about 1.3 times the diameter of the bluff body should. The corresponding advantageous dimension range of the second stage is between 0.7 to 1.7 times the diameter of the bluff body.

The device according to the invention for igniting or burning fuels, which is preferably to be used as a heating device, is advantageous with an insert according to the invention or according to one of the previously discussed preferred embodiments.

It is also particularly advantageous if the device according to the invention is equipped with at least one blower device that enters the combustion chamber Combustion gas or combustion air supplies. This is due to the air flow preferably creates an overpressure in front of the baffle plate, while behind the Baffle plate a negative pressure is generated. The use with its preferably in Groups of at least substantially equally designed sections or Lamellas ensure that the feed is distributed in the longitudinal direction Combustion air, with the advantageous consequences listed above. Here the air required for combustion is at a pressure of about 4 to 30, preferably 6 to 20 millibars, on the bluff body or the baffle plate. A lower overpressure is sufficient for smaller burner capacities, while for larger burner capacities a higher overpressure or the resulting Vacuum is preferable to the flame in the desired, given Area.

Fig. 1

eine aufgeschnittene Seitenansicht eines erfindungsgemäß ausgestalteten Einsatzes;

Fig. 2

eine Ansicht einer Ausführungsform des erfindungsgemäß ausgebildeten Einsatzes in einer Frontalansicht;

Fig. 3

eine Fig. 1 entsprechende Ansicht, wobei anstelle einer Öleinspritzdüse (Fig. 1) eine Gaszuführeinrichtung angeordnet ist;

Fig. 4

einen Einsatz mit einem alternativ ausgebildeten Staukörper in einer aufgeschnittenen Seitenansicht;

Fig. 5

einen erfindungsgemäßen Einsatz in einer Frontansicht, wobei diese Figur auf Abmessungsverhältnisse gerichtet ist;

Fig. 6

in einer aufgeschnittenen Seitenansicht eine Ausführungsform eines Einsatzes mit einer zusätzlichen Rezirkulationseinrichtung;

Fig. 7

eine aufgeschnittene Seitenansicht einer Ausführungsform eines Einsatzes mit einem Stabilisationsring;

Fig. 8

eine aufgeschnittene Seitenansicht einer Ausführungsform eines Einsatzes mit einem unterschiedlich angeordneten Stabilisationsring; und

Fig. 9

eine aufgeschnittene Seitenansicht einer Ausführungsform eines Einsatzes mit mehreren Stabilisationsringen.

The present invention is explained in more detail below on the basis of preferred embodiments with reference to the attached figures, further advantages and features according to the invention being disclosed. Show it:

Fig. 1

a cut side view of an insert designed according to the invention;

Fig. 2

a view of an embodiment of the insert designed according to the invention in a front view;

Fig. 3

a view corresponding to FIG. 1, wherein a gas supply device is arranged instead of an oil injection nozzle (FIG. 1);

Fig. 4

an insert with an alternatively designed bluff body in a cut-away side view;

Fig. 5

an insert according to the invention in a front view, this figure is directed to dimensional relationships;

Fig. 6

a cut side view of an embodiment of an insert with an additional recirculation device;

Fig. 7

a cut side view of an embodiment of an insert with a stabilizing ring;

Fig. 8

a cut side view of an embodiment of an insert with a differently arranged stabilization ring; and

Fig. 9

a cut side view of an embodiment of an insert with several stabilization rings.

In the figures, they are functionally identical or at least essentially functionally matching components usually with the same reference numerals featured.

1 shows a preferred embodiment of an embodiment according to the invention Insert marked with the reference number 1. The insert 1 surrounds a baffle plate 2, an oil atomizing nozzle 4 and an ignition device 3.

The insert 1 according to the invention has two groups of at least essentially identically designed sections or lamellae 10, 12 by a Base body 11 go out. The slats 10 are in the longitudinal direction of Oil atomization nozzle 4 shorter than the fins 12 of the second group or second Level of use 1 designed according to the invention.

The sections or lamellae 10 have a first one from the wall of the insert 1 angled section 10a, which has a continuous rounding in passes over a second, further inwardly bent section 10b. The slats 10 end at their in the longitudinal direction of the oil atomization device or nozzle 4 front end 10c. The air supplied from the rear is over the Slats 10 guided into the interior of a combustion chamber in which this insert 1 is arranged. The sections or lamellae 10 are designed such that not enough air is led inwards to the supplied Amount of fuel to supply appropriate amount of combustion air, which in In a defined area there is a lack of oxygen, which leads to the supplied fuel where it would otherwise, if there is sufficient air supply would be present, is not completely burned. This will reduce the combustion temperatures reduced and less nitrogen oxides are generated.

The sections or slats 12 are in the area in which the slats 10 are already bent inwards towards an axis of symmetry of the insert, still aligned unchanged in the direction of extension of the base body of the insert 1. In other words, a section 12a of each lamella 12 leaves the Airflow of the supplied combustion air in an area in which the fins 10 are already effective, essentially unaffected. Later, in one Area 12b, the fins 12 ensure that a further portion of the combustion air is distracted inwards. Ensure end portions 12c of the fins 12 ultimately for the fact that the further portion of the combustion air is also inside is passed, whereby the still for the at least substantially complete Combustion of the supplied fuel required combustion air supplied is, which burns the unburned portions of the fuel can be.

It is advantageous as far as between the first slats 10 and second slats 12 Slits (see Fig. 1) are available to close them or during manufacture the slats to ensure that no slits are formed. Existing slots can e.g. can be closed by welding sheet metal. Slots can otherwise avoided by suitable plastic deformation of the insert wall will.

Would the group of first fins 10 and the group of second fins 12 are each formed as a closed funnel or cone, so the Flame speed in the area of the constriction increase so much that the Flame speed would be greater than the ignition speed of the oil-air mixture or a gas-air mixture (see Fig. 3). This would take off lead to the flame, which would create undefined conditions.

The baffle plate 2 has an at least approximately central hole or a central one Opening 2a through which fuel can pass. A section 2b serves as an obstacle to a stream of combustion air coming from behind. This can be substantially perpendicular to the direction of extension of the nozzle 4 or downstream greatly flared or slightly receding towards the outside be trained. That is, section 2b is from the radial plane of the Opening 2a starting at an angle above 0 °, preferably about 5 ° to 15 ° or 20 ° deflected. Larger angles up to 35 ° and beyond are also available usable. The section 2c adjoining the section 2b faces the radial plane preferably at an angle of about 50 ° to 90 °. At this section 2b another section 2c follows at about 2/3 of the radius of the insert 1. This is slightly tapered downstream in the direction of extension of the nozzle 4 and about the same length as section 2b. Between the widened There is a gap between the end of section 2c and the inside of insert 1 of preferably about 1/12 of the inner diameter of the insert 1, wherein this Distance approximately between 1/10 and 1/14 of the inner diameter of this insert 1 can lie. The sections 2c of the bluff body or the baffle plate 2 provide for the fact that the portions of the combustion air bypassed the baffle plate in reach the effective range of the slats 10, 12.

The combustion air supplied from behind, for example by means of a fan, is at section 2b of the baffle plate 2. Here arises in the direction of fuel ejection an overpressure zone in front of the baffle plate, in which an overpressure can preferably prevail between 6 and 20 millibars. Part of the air is passed through the opening 2a of the baffle plate 2, while the remaining Amounts of combustion air through the space between the baffle plate 2 and the insert 1 is passed through. In the fuel discharge direction behind the baffle plate 2 or behind the section 2b creates a vacuum zone, which causes the flame to be held at a predetermined point can. Accordingly, the baffle plate is also referred to as a flame holder. The negative pressure created by the baffle plate 2 is extended in one Area due to the divided supply of combustion air via the fins 10, 12 balanced, and the room in which otherwise the combustion of the fuel would run is in the longitudinal direction over a larger area extends, the combustion temperatures and thus the proportion of nitrogen oxides is greatly reduced.

2 that the lamellae 10 are bent further inwards, while the fins 12 are arranged on a larger diameter. Depending on Type of heating device in which the insert according to the invention is used the slats 10, i.e. the shorter slats, also less far behind be curved on the inside, in particular less far than the longer slats 12.

Inside, between the fins 10, 12 of the insert 1, the bluff body or to recognize the baffle plate 2. Between the edge 2d of the baffle plate 2 and the the diameter given by the fins 10 is still a top view short distance remained. However, the slats 10 can also continue be curved inside, so that here in the top view the space between the Insert 1 and the baffle plate 2 can no longer be seen. The same can also apply to the slats 12.

In the case of the embodiment according to FIGS. 1 and 2, the slats 10, 12 same size. However, it is also possible to make the slats 10 larger or larger to be smaller than the lamellae 12 in order to achieve certain effects in the control to achieve the flow of combustion air.

The baffle plate 2 has a plurality of recesses 2e, about their dimensions the negative pressure created behind the baffle plate or that in front of the baffle plate arising overpressure, as well as that behind the baffle plate standing amount of combustion air, can also be set.

3, the insert 1 or the baffle plate 2 are in principle the same designed as the relevant parts according to FIGS. 1 and 2.

Instead of the oil atomization nozzle 4, however, there is a gas nozzle 5 with a plurality of Openings provided. Some of the openings are located in front of the baffle plate, while part of these openings through which the gaseous fuel can pass behind the baffle plate 2. However, it is also possible to arrange all the openings of the nozzle 5 behind the baffle plate 2, or the Openings of the nozzle 5 in a different way in front of or behind the baffle plate to arrange. It is only necessary to have an appropriate air supply Way to control, for example by opening 2a or other components of the baffle plate 2 are dimensioned differently, or the Free space between the baffle plate 2 and the insert 1 is dimensioned differently. Accordingly, the slats 10 and 12 can also be dimensioned in such a way that a different arrangement of the nozzle 5 becomes possible. The same applies for the embodiment according to FIGS. 1 and 2 or the nozzle 4.

In FIG. 4, in contrast to the embodiment according to FIG. 1, there is a baffle plate 2 provided with cylindrical side walls 2c. The cylindrical Side walls 2c run at a right angle to section 2b of the baffle plate 2. The section 2c of the baffle plate has extended sections 2f, so that the end 2d of the baffle plate 2 further in the fuel discharge direction is extended and once has a smaller extension. This allows the Also influence the flow of the combustion air and thus the vacuum range adjust beyond the baffle plate 2.

As can be seen, the individual lamellae 10, 12 all begin along the same origin line 14. Provided the slats by cutting or punching out are made from the material of the base body of the insert 1 to prefer this. However, if the material is drawn, the line of origin can of the slats 10 with respect to the line of origin of the slats 12 also be offset in the longitudinal direction.

The distance between the rear end line 2d of the baffle plate 2 and the front Experience has shown that the end 10c of the slats 10 can preferably be about 0 to 0.5 times the diameter of the insert 1.

As can be seen from Fig. 5, the division of the slats of the insert or the respective groups or levels of slats from 4 to 24 or even go beyond. The inner diameter of the longer fins 12 can be between 0.5 and 1.5 times the diameter of the baffle plate 2. The preferred range is between 0.7 and 1.3 times the diameter the baffle plate 2. The inside diameter defined by the fins 12 is formed, from about 0.5 to 2 times the diameter of the Baffle plate 2 can be created, but with a range of 0.7 to 1.7 times Diameter of the baffle plate 2 is preferred.

FIG. 6 also shows an overtube 20 which is used for the in gases present in the combustion chamber due to the flame speed or to recirculate the gas flow caused by the flame. This measure can lead to additional afterburning of fuel residues. The The overtube 20 can have approximately the same diameter as the insert 1 have or a slightly larger diameter than the base body of the Insert 1 has. A slightly smaller diameter could also be considered be considered expedient, the overtube 20 with the fins 10, 12 corresponding slats could be provided.

While in the above embodiments only two groups of each Slats 10, 12 have been described, it is also easily possible, a third or further groups of at least substantially equally trained To provide slats with a different longitudinal extent.

The main advantage of the arrangement according to the invention from insert 1, the Baffle plate 2 and the nozzle 4 and 5, also referred to as the combustion head is, among other things, in a very substantial reduction in the See share of nitrogen oxides.

The one for an application according to the invention or a combustion head according to the invention In contrast, the estimated effort is relatively low, so that a cost / benefit analysis is clearly in favor of the benefit. The use according to the invention can also be used in a very economical manner use conventional heating burners. The renovation work required for this are, are only very small and can be, if necessary, by a corresponding Modification of the use designed according to the invention is usually the largest Do part.

7 shows an embodiment according to the present invention, those with regard to the arrangement and design of the insert 1 or the flame tube 1, the baffle plate 2 and the ignition device 3 or the fuel nozzle 4th is designed to be comparable to the embodiment according to FIG. 1. Instead of Embodiment according to FIG. 1 can of course also corresponding training 3, 4 or 6 can be used to those discussed below to provide for essential technical changes.

7 is on the longer slats 12 on the front, inwards directed edge 12d of the slats 12 provided a ring 28 which is substantially is rigidly connected to each of the slats 12 of this slat group. The ring 28 acts on the air flows as well as on the flame and the mechanical Stability of insert 1 self-stabilizing. Ring 28 is preferred trained closed.

This very advantageous training makes it possible, on the one hand, to area in which the combustion occurs to stretch, creating a more perfect combustion is achieved, and on the other hand it is possible in a predetermined by the ring 28 Area to provide a particularly strict control of the flame, which, however, due to the axial gaps between the shorter lamellae 10 and the longer slats 12 can at least partially be dissolved again.

In the embodiment shown in FIG. 8, one corresponding to the ring 28 Ring 26 set on the shorter blades 10. This also makes the in 7 discussed and also set out in the introduction to the description Benefits achieved.

In the embodiment shown in FIG. 9, both groups are lamellae 10, 12 equipped with corresponding rings 26, 28, so that the effects discussed can be reinforced or combined.

Claims (8)

1. Insert for a device for igniting or burning fuels, more particularly for a heating device

   a) by preference with a cylindrical main body (11) and

   b) with at least two sets of sections (10, 12) assigned to the main body (11), whereby

   c) in the fuel ejection route or in the route of longitudinal extension of the insert (1), the sets of sections (10, 12) each end at different distances from a fuel ejector (4, 5), characterised in that

   d) at least one retaining element (2) is situated in the area of the insert (1), before or in the course of the fuel ejection route and

   e) each set comprises sections (10, 12) which essentially have an identical inward curve towards the cylinder axis of the main body (11), whereby each section set ends at a diametral area.
2. Insert according to Claim 1, characterised in that the front and/or rear sections (10, 12) are connected to one another in circumferential direction via a circulating extension (26, 28), whereby the extension(s) (26, 28), by preference, takes the form of a ring or a cylinder, extending in a radial and/or axial direction from the main body (11).
3. Insert according to one of Claims 1 or 2, characterised in that, by preference, the retaining element (2) has a cylindrical, conical or funnel-shaped expanding area (2c), extending in the fuel ejection route or in the route of longitudinal extension of the fuel ejector (4, 5).
4. Insert according to Claim 3, characterised in that the area (2c) has part areas (2f) which extend to differing degrees in the fuel ejection route or in the route of longitudinal extension of the fuel ejector (4, 5), and the retaining element (2), in particular around the essentially central opening (2a), may have recesses (2e) which are connected with the latter.
5. Insert according to one of Claims 1 to 4, characterised in that a pipe (20) is provided as a continuation of the main body of the insert (1), by preference partly covering it.
6. Insert according to one of Claims 1 to 5, characterised in that at least one further insert surrounding the insert is present, with sections (10, 12) which are directed inwards and/or extended to different degrees.
7. Insert according to one of Claims 3 to 6, characterised in that the distance between one rearmost front edge (2d) of the retaining element (2), in the fuel ejection route or the route of longitudinal extension of the fuel ejector (4, 5), and the end (10c), provided in the route of longitudinal extension, of a similarly formed section or a corresponding stage is approximately 0 to 0.5 times the diameter D of the insert (1), whereby, if applicable, the diameter, particularly the internal diameter, which is formed by the shorter sections (10), is approximately equal to 0.7 to 1.3 times the diameter of the retaining element (2) or, if applicable, the diameter or internal diameter which is formed by the longer sections (12) or formed by the second stage or set of sections (12) is approximately equal to 0.7 to 1.7 times the diameter of the retaining element (2).
8. Device for igniting or burning fuels, more particularly a heating device

   a) with at least one fuel ejector (4, 5),

   b) with a combustion chamber,

   c) with an insert surrounding the fuel ejector (4, 5) in the fuel ejection route or in the extension route of the fuel ejector (4, 5), with the characteristics of at least one of Claims 1 - 7.

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