EP1030106A2 - Blue-flame burner with optimized combustion characteristics - Google Patents

Abstract

The burner has a housing (10) with a flame tube (14) enclosing the combustion chamber (92) and behind this is an pre- combustion chamber (48) with a central nozzle assembly (24) from where the fuel stream broadens out within the combustion chamber. A dividing wall separates a fan in the pre-combustion chamber from the combustion chamber, the fan forcing sufficient air (102) through for approximately stoichiometric combustion with a blue flame. There is a second stream of combustion air (106) entering the chamber a short distance away from the first stream and radially outside it. Its purpose is to stabilise recirculation in the chamber.

Description

The invention relates to a burner for liquid media comprising a burner housing which a support tube and a adjoining flame tube, one in the Support tube arranged in a prechamber with nozzle a nozzle generating a fuel jet, one in the Flame tube arranged essentially mixing tube-free burner chamber in which the fuel jet spreads Separating element between the prechamber and the combustion chamber a central opening through which the fuel jet passes, a fan for generating a in the combustion chamber incoming combustion air flow, which is close to the fuel jet Partial stream includes, being in the combustion chamber the fuel with a blue-burning flame essentially burns stoichiometrically or near stoichiometrically.

DE-OS 40 09 222 discloses a burner for stoichiometric Burning liquid or gaseous fuels from an atomizer nozzle. This burner is around the atomizer nozzle through an aperture in air Combustion chamber guided, in which the emerging from the nozzle Fuel also occurs.

In addition, are in the wall of the combustion chamber parallel to Slit-shaped openings running in the direction of flow are provided, through which a recirculation of cold combustion gases from outside the burner tube leading to the Fuel and that entering around the atomizer nozzle Air can be added to make a stoichiometric in the combustion chamber To get combustion.

EP-A-0 430 011 also discloses a blue-burning one Burner in which there is a mixture around an atomizing nozzle from fresh air and recirculating combustion gases and be mixed before again with that of the Atomizer nozzle coming to a stoichiometric fuel Cause combustion.

In all of the exemplary embodiments, in front of the level, in which is an orifice of the nozzle, a mixture of combustion air and recirculating combustion gas and after This mixes the combustion air in a mixing chamber and the recirculating combustion gases with the fuel, which then enter the actual combustion chamber. At special embodiments is the supply of Fresh air divided, on the one hand, into a first part, the directly mixed with the recirculating combustion gases, and on the other hand in a second part, which the Flows around the atomizer nozzle and serves to close the atomizer nozzle cool so that the cooling of the atomizer nozzle, in particular the oil nozzle, is adjustable. This fresh air is then also in a mixing chamber with the remaining fresh air and the recirculating combustion gas as well as the fuel mixed.

A controllable burner is known from DE-OS 27 12 564, in which a baffle plate is present and downstream the baffle plate creates a negative pressure area by generating a rotating hollow air column is created so that combustion gases be sucked back into this vacuum area. The rotating hollow air column is thereby in radial Radial slots running in the direction and covered with scoops generated.

In addition, there are external air supplies for higher outputs intended for fresh air.

In addition, the atomizer nozzle with the ignition electrodes is in arranged in a closed room, which only so much fresh air is supplied as required to move the spark is.

DE-PS 29 08 427 discloses a burner in which first a sub-stoichiometric one with the addition of flue gases Combustion in a primary combustion zone with immediate supply of one that envelops the fuel flow Jacket air flow takes place and then in a superstoichiometric secondary combustion zone, in the residual air over the peripheral area of the primary combustion zone is fed, further combustion takes place.

The residual air is coaxial around the respective burner fed around regulated in at least two sub-flows, the from the burner mouth after a certain free flow path reach the flame.

A so-called blue burner is known from DE-OS 31 09 988, in which an internal recirculation via a mixing tube is forced, the one emerging from an atomizing nozzle The fuel jet on the one hand surrounds this directly Combustion air is supplied and on the other hand further air passage holes are provided radially on the outside are, however, radially inside the mixing tube lie.

EP-A-0 538 761 describes a burner with recirculation known in which the external recirculation by a longitudinal direction of the slots is generated, this Slots run with their longitudinal direction in the circumferential direction.

In addition, fresh air that flows around the nozzle is through an orifice is blown into the combustion chamber.

Similar burners are for example from DE-PS 27 00 671 or DE-PS 38 01 681 known.

These burners are designed to form a stable recirculation flow a so-called mixing tube is required which is a single recirculation flow of hot gas sets and thus enables a blue burning of the flame.

A flame burning blue means that this flame burns a completely gasified fuel, what especially when using oil as fuel Requires that from the nozzle in the Small oil droplets first emerging from the fuel jet until completely burned by the flame to evaporate.

The problem with these known burners is that the overall design of the burner is a coordination of all parts required for a single burner output, so that a burner for other burner capacities a completely new design required.

Starting from DE-OS 40 09 222, the invention is the Task based on a burner of the generic type to improve that as low a pollutant and stable stoichiometric or near stoichiometric combustion allowed.

This task is described in the case of a burner Art solved according to the invention in that in the combustion chamber in addition to the partial stream close to the fuel jet recirculation-stabilizing partial flow of combustion air occurs, which is compared to the partial flow near the fuel jet Radially external individual flows at a defined distance includes that one of the blue-burning flame to the non-burning part of the fuel jet retreating inner recirculation flow trains and that the recirculation-stabilizing partial flow the combustion air stabilizes the internal recirculation flow.

The advantage of the solution according to the invention can be seen in that through the additional recirculation stabilizing Partial flow of the combustion air stabilizes the inner Recirculation flow in the combustion chamber is possible.

This creates a burner, through which locally defined supply of the combustion air flow there is the possibility essentially without mechanical flow guiding Elements in the combustion chamber have stable recirculation flows and thus ensure a blue burning of the flame.

As an alternative or in addition to this, the above is mentioned Task with a burner of the type described above solved according to the invention in that in the burner housing Openings are provided through which a cold combustion gas leading external recirculation flow into the Combustion chamber enters the outer recirculation flow enters the combustion chamber near the separating element and so is great that a flame root of the blue-burning flame is at least 1 cm from the nozzle, and that there is a non-burning between the nozzle and the flame root Part of the fuel jet with the addition of Combustion air spreads out conically.

The advantage of this solution according to the invention is in particular to be seen in the fact that the external recirculation flow, the according to the prior art was only used the content of harmful combustion gases, in particular To reduce nitrogen oxides, are now used according to the invention the flame root at a sufficiently large distance to be positioned by the nozzle, namely in that the external recirculation flow sufficiently additional essentially not oxidizing or only slightly oxidizing Gas is introduced into the combustion chamber, thus the Mass flow through the combustion chamber increased and thus the necessary Distance between the flame root and the nozzle, which is required to have a sufficiently long to get the non-burning part of the fuel jet, the is required to completely evaporate the droplets to reach.

In particular, in this embodiment, the sufficient length of the non-burning part of the fuel jet created the opportunity to get the hot gases out the inner recirculation flow the non-burning part of the fuel jet and thus the possibility of the oil droplets in the fuel jet with certainty to evaporate to the flame root, so that ultimately one stable blue-burning flame that is highly insensitive against minor changes in the setting parameters is.

Alternatively or in addition to those described above Solutions to the above task at a Burner of the type mentioned in the introduction solved that openings are provided in the burner housing, through which an external, cold combustion gas leading Recirculation flow enters the combustion chamber that external recirculation flow near the separating element in the Combustion chamber enters and that this is an internal recirculation flow shields against the separating element, which itself as in the combustion chamber from the blue-burning flame to the non-burning part of the fuel jet retreating Current forms.

In this solution according to the invention, this is usually the case to reduce pollutants, especially nitrogen oxides, external recirculation flow used according to the invention used to the hot combustion gases of the inner Recirculation flow compared to the cold separator shielding and thus cooling them too much Prevent combustion gases through the cold separator. Rather, these hot combustion gases essentially become with little or no cooling of the fuel jet supplied to the best possible by the heat input To ensure evaporation of the oil droplets.

The solution according to the invention also has in connection with the use of an external recirculation flow great advantage that due to the lack of mechanical Flow control elements in the combustion chamber, in particular due to the missing mixing tube, no problems with pollutant emissions that occur at the start of the burner cause the external recirculation to vary must be set. Rather, the invention Solution the big advantage that already at the start of the Optimal low-pollution combustion takes place, so that the laborious regulation of external recirculation, like described for example in DE-PS 39 06 854, although still can be carried out, however, due to the available good pollution levels without this regulation is required.

With regard to the course of the internal recirculation flow No further details have so far been given in the combustion chamber. An advantageous exemplary embodiment provides that the inner recirculation flow originating from the flame on an inside of the flame tube towards the Separator flows. In this position, the inner Recirculation flow through the recirculation stabilizing Partial flow of the combustion air is particularly simple and sustainable stabilize.

In a particularly useful embodiment with inner recirculation flow is the inner recirculation flow burning yellow.

A particularly beneficial effect of the internal recirculation flow, especially with regard to heat transfer on the fuel jet to evaporate the oil droplets reach themselves when the inner recirculation flow through the recirculation-stabilizing partial flow passes through.

Regarding the direction in which the recirculation stabilizing Partial flow were entering the combustion chamber in connection with the previous explanation of the exemplary embodiments no details given. For example could the recirculation-stabilizing partial flow in parallel be directed towards the cone of the fuel jet. Especially However, it is advantageous if the recirculation stabilizing Partial flow essentially parallel to the direction of flow of the fuel jet enters the combustion chamber.

It is particularly advantageous if the partial streams are independent of the set amount of air on the same Enter the combustion chamber.

By locally determining the entry of the partial flows in the combustion chamber can stabilize the recirculation flow with every adjustment of fuel quantity and Air volume particularly advantageous with the simplest of means to reach.

In connection with the previous explanation of individual exemplary embodiments was not discussed about which Partial flows the air volume is set.

From the combustion calculation it would be theoretically possible via the partial stream close to the fuel jet or via the recirculation-stabilizing partial flow or over both the To make air volume adjustable.

For the sake of simplicity and a streamlined Solution, however, it is advantageous if to adjust the Air volume only one of the partial flows to adapt to the The amount of fuel is adjustable.

To stabilize the recirculation flows in everyone Setting the amount of air and amount of fuel has turned out to be proven particularly useful when the recirculation stabilizing Partial flow adjustable with regard to the air volume is. About the adjustability of the recirculation stabilizing Partial stream can be particularly advantageous Stabilization of the recirculation flow with every burner output achieve because this partial flow directly on the training of the recirculation flows and thus one The same setting can be made so that the recirculation flow is direct due to the local entry of this Partial flow can be stabilized in the combustion chamber.

The recirculation-stabilizing partial stream preferably occurs in the form of a ring flow interrupted in the circumferential direction to their fuel jet into the combustion chamber, whereby the stabilization of the recirculation flow still is further improved since at the points of the interruption a "flow" of the ring current in the radial direction in is easily possible while between breaks stabilizing vortices are generated.

Because at maximum fuel quantity a maximum gas velocity occurs in the flame, it is also particularly advantageous if the amount of air in the recirculation stabilizing Partial flow at maximum fuel quantity maximum and at minimum amount of fuel is minimal, so the amount of air of the recirculation-stabilizing partial flow at maximum Amount of fuel and thus the highest gas velocity Flame also has sufficient recirculation flow for maintains a blue flame burning in the combustion chamber.

Regarding the adjustability of the recirculation flow it has also proven to be advantageous if the amount of air in the partial stream close to the fuel jet with all settings the amount of fuel is constant, so that the partial flow near the fuel jet always a basic supply of the Ensures fuel jet with air. In extreme cases the amount of air in the partial stream near the fuel jet is dimensioned so that at the maximum amount of fuel, the amount of air in recirculation-stabilizing partial flow is maximum and minimal amount of fuel the combustion air flow only through the sub-stream close to the fuel jet is formed.

In an advantageous embodiment of the invention It is provided that the amount of air in the vicinity of the fuel jet Partial flow between approximately 0.6 times and about 0.2 times the amount of air at the maximum recirculation-stabilizing partial flow, this being is provided in particular in a burner, the Burner output can be varied by a factor of five.

With regard to the type of formation of the fuel jet were in the explanation of the previous embodiments no details given. This is how one looks special simple and effective working embodiment before that the fuel jet is one of a simply connected Nozzle outgoing pointed cone, in particular essentially a full cone, in which the most homogeneous possible distribution of droplets of the oil is present.

With regard to the alignment of the partial flow close to the fuel jet when entering the combustion chamber were also still no details given. So looks an advantageous one Embodiment that the near-fuel partial flow in essentially parallel to the flow direction of the Fuel jet enters the combustion chamber.

The partial stream close to the fuel jet preferably occurs in the process flowing around the fuel jet into the combustion chamber a good mixing of this part of the combustion air with the Allow fuel jet in the combustion chamber.

This can be achieved particularly advantageously if the partial stream close to the fuel jet and the fuel jet through the same central inflow opening in the separating element in the Enter the combustion chamber.

Regarding the location of the supply of the near fuel jet So far, no partial flow into the combustion chamber has been identified Information provided. This is an advantageous embodiment that the sub-stream near the fuel jet in the area a periphery of the nozzle head of the nozzle flows into the combustion chamber.

However, it is even more advantageous, particularly because of the spatial conditions in the area of the nozzle when the fuel jet is close Partial flow along a defined outer profile of the nozzle head flows and therefore in the immediate vicinity of the fuel jet enters the combustion chamber.

In the simplest case, this can be done for those close to the fuel jet Partial flow required cross section available ensure that the partial flow near the fuel jet passes through a passage between the nozzle head and an edge of one for the inflow opening provided near the fuel jet flows into the combustion chamber so that the size of the Pass through the flow cross-section for the fuel jet Specifies partial flow.

A particularly advantageous mixing of the near fuel jet Partial flow and the fuel in the combustion chamber results when the inflow opening for the designed to generate turbulence is.

In the simplest case, it is provided that the inflow opening with a swirl edge or a swirl cutting edge is.

With regard to the construction of the burner housing were related with the previous embodiments none detailed information. So looks an advantageous one Embodiment before that the burner housing a prechamber comprises, in which the nozzle is arranged and which is separated from the combustion chamber by the separating element. On Such construction of the burner housing has the advantage of great simplicity and high structural flexibility.

In connection with the previous exemplary embodiments was not discussed in more detail, like the combustion air flow is led into the combustion chamber.

It is particularly advantageous if the entire combustion air flow is passed through the antechamber as this a particularly simple construction of the burner guaranteed.

This is also for reasons of constructive simplicity preferably provided that the combustion air flow through the separating element enters the combustion chamber.

With regard to the guidance of the combustion air through the separating element is expediently provided that the separating element Inlet opening facing the nozzle for the fuel jet Has partial flow.

In addition, it is expediently provided, in particular around the recirculation-stabilizing partial flow on the desired place in the combustion chamber to let that the separating element relative to the inflow opening for the partial stream near the fuel jet at least one radially external Opening for the recirculation stabilizing Has partial flow.

Regarding the design of the combustion chamber have been related with the previous embodiments also no details given. So looks an advantageous one Embodiment before that the combustion chamber of a flame tube of the burner is enclosed, so that this flame tube of the burner a defined geometric environment of the combustion chamber and thus in particular a defined training of Allows recirculation flows.

This flame tube is preferred for lowering the nitrogen oxide emission with openings for the formation of the external recirculation flow Mistake.

With regard to the design of the combustion chamber itself, Connection with the previous description of each Exemplary embodiments made no further details. So look an advantageous embodiment that the combustion chamber extends from a plane that is close the nozzle opening. Such training the The combustion chamber allows optimal guidance of the individual Recirculation currents, especially the inner and the external recirculation flow to the non-burning part of the fuel jet.

A particularly simple and efficient design of the combustion chamber provides that this between the separator and the Area of the flame root has a substantially constant Has cross section. This gives the advantage of being sufficient Space for guiding and training the recirculation flows, especially the inner recirculation flow is available.

No specific information was given regarding the separating element made. For example, the separating element according to of EP 0 430 011. Constructively special however, it is simple if the separating element is an aperture.

The aperture in turn could also be curved be as follows. As for example from DE-OS 40 09 222 known. However, it is particularly advantageous if the aperture extends in a plane because such a form of Aperture also optimally guides the recirculation flows to the non-burning part of the fuel jet in the Area of the aperture allowed.

It is particularly favorable if the combustion chamber moves away from you penetrate the non-burning part of the fuel jet and has around this recirculation space, what optimal options for feeding the individual Recirculation flows to the non-burning part of the Offers fuel jet.

The recirculation space is expediently designed in such a way that that it extends at least to the flame root, to have enough space for the internal recirculation flow to accomplish.

In order to stabilize the recirculation flows particularly optimally it is envisaged that the recirculation stabilizing Partial stream enters the recirculation room.

The recirculation-stabilizing partial stream is preferably formed so that it is symmetrical about an axis of the combustion chamber and thus to an axis of the recirculation space in this occurs.

The recirculation-stabilizing partial stream is preferably designed so that it lies in the form of a cylinder Current image enters the combustion chamber. This form of the recirculation-stabilizing partial flow enables one particularly optimal stabilization of the internal recirculation flow.

In particular, the cylinder is designed as a circular cylinder, which lies through one in the middle of it Pitch circle is set.

With regard to the current picture, no further details were given made. For example, it would be possible to view the current picture as a uniform closed ring flow in the form of Cylinder. However, it is particularly advantageous if the current picture is composed of parallel component streams is because these item streams the possibility create the recirculation flows in a particularly advantageous manner through the recirculation stabilizing Partial flow in the area of the non-burning part of the fuel jet to let it pass through.

This is particularly advantageously possible when the component streams arranged at a constant angular distance from each other are to defined gaps between the individual component flows to create through which the recirculation flows can step through.

With regard to the dimensioning of the component flows in relation it has to the angular distances between them proven to be particularly advantageous when the ratio of Angular distance between two component streams to the angular width the inlet cross-section of each component flow is between about 10 and about 0.1.

It is more advantageous if this ratio is between approximately 3 and about 0.1, better between about 2 and about, 0.1, more preferably between about 1 and about 0.1, and it has proven particularly optimal if this Ratio in the range of about 1.5 to about 0.3 lies.

Furthermore, no further details on the Dimensioning of the recirculation space made. Preferably it is provided that the circular ring area has a pitch circle diameter which is in a range of approximately 0.2 to about 0.7 an outer diameter of the combustion chamber or the recirculation room

A particularly optimal effect of the recirculation stabilizing Partial flow can be achieved if the recirculation space, one for example the inside diameter of the Flame tube has the corresponding outer diameter, which is about 1.5 to 3 times larger than the diameter of the Pitch circle of the circular cylinder.

It is even more advantageous if the recirculation space is one Outside diameter, which is about 1.8 to about 2.6 times, more preferably about 2 to about 2.5 times, larger is the diameter of the pitch circle of the circular cylinder. Particularly optimal results have been obtained if the Outside diameter of the recirculation space approximately 2.4 ± 10% times as large, more optimally about 2.5 times, as large as the pitch circle diameter.

In particular to optimally stabilize the flame, and to prevent the flame from flickering spatially, it has turned out to be proven particularly useful when referring to the recirculation space a flame chamber connects.

This flame chamber can have the same inner diameter for large outputs have as the recirculation space, in particular for small services, however, it has to do with spatial stabilization proved to be advantageous if the flame space has a maximum diameter is the same size or smaller than the recirculation space.

Particularly preferred values result when the diameter of the flame space in the range of approximately 0.6 to 0.9 times of the diameter of the recirculation space. Especially It is advantageous if the inner diameter of the flame space in the range of approximately 0.8 times the inner diameter of the Recirculation space.

With regard to the expansion of the combustion chamber, too no defined information given. Also around the flame Keeping it as stable as possible has proven advantageous proven if the flame is one in the combustion chamber Has flame root.

Regarding the initiation of the external recirculation flow No detailed information has so far been placed in the combustion chamber Information provided. For example the initiation of the external recirculation flow into the Combustion chamber take place in accordance with EP 0 430 011. Especially However, it is advantageous if the outer recirculation flow separated from the combustion air flow into the combustion chamber entry.

This embodiment has the great advantage that the outer recirculation flow is defined on the one hand lead and on the other hand with regard to the mass flow can also be defined defined what for the invention Aspects, especially the guidance of the external recirculation flow to shield the internal recirculation flow from the separating element and the dimensioning of the Mass flow to achieve a sufficiently long non-burning Part of the fuel jet is important. This is also the volume for the internal recirculation flow fixed.

This can be done constructively with particularly simple means then reach when the outer recirculation flow through Recirculation openings in the flame tube directly into the combustion chamber entry.

With regard to the dimensioning of the external recirculation flow So far, no quantitative information has been provided made. An advantageous exemplary embodiment provides that an area of the entry for the combustion air flow in openings provided in the combustion chamber approximately the area of the recirculation openings provided in the flame tube for the outer recirculation flow. With this dimensioning a is sufficient large mass flow in the recirculation flow ensures around a sufficiently elongated part of the non-burning Get fuel jet in the combustion chamber.

It is also possible to have a flow stabilization element in the flame tube to arrange, which is from the aperture in Direction of a foot area of the flame up to a maximum of approximately over a quarter of the distance between the aperture and the Flame extends. This flow stabilization element has nothing to do with what is known from the prior art Mixing tube, since the known mixing tube is only the formation of a single recirculation flow while the inventive Flow stabilization element also like this is trained that it is the formation of several by the Recirculation-stabilizing partial flow of definable recirculation flows allows, especially the training of required for the respective fuel quantities and air quantities Recirculation currents.

For this reason, it is particularly advantageous if the flow stabilizing element a maximum of about one Sixth of the distance between the bezel and the foot area the flame extends.

The flow stabilization elements explained above are, however, for the sufficient stabilization of recirculation flows not absolutely necessary and always create the risk of soot deposits in the burner.

Especially when soot deposits in the combustion chamber like this to be prevented as well as possible is advantageous provided that the combustion chamber be free from within the same arranged flow stabilization elements for the Recirculation is formed.

In particular, the combustion chamber - as already mentioned at the beginning mentioned - trained without mixing tube.

On the question of setting the air volume of the combustion air flow no further details have so far been given. So one sees advantageous embodiment before that for adjustment an adjustment device for the air volume of the combustion air flow is provided.

The setting device is preferably designed such that with an adjustment of the air volume the place of entry of the Combustion air flow into the combustion chamber in the radial direction Fuel jet is essentially invariant. This has the great advantage that by determining the location of the Entry of the combustion air flow an optimal stabilization the recirculation with all fuel quantity settings and amount of combustion air is possible.

It has proven to be particularly advantageous if the adjusting device Locally fixed openings for the combustion air flow which has different cross sections are adjustable.

Conveniently, this is solved constructively so that the Adjustment device an adjusting element rotatably mounted on the panel with which the cross section of one in the Aperture provided opening is adjustable.

In the simplest case, the setting element can be rotated formed on the bezel shim, which in different rotational positions relative to the aperture and the openings provided in the panel can be brought.

On the one hand, this setting element can be designed that it is adjustable in different discrete setting positions is.

Alternatively, it is advantageous if the adjusting element is continuously adjustable so that it is continuous the cross sections between a maximum value and a The minimum value can be varied.

The adjusting device can be designed so that it manually, for example with an appropriate tool, is adjustable.

It is special in the case of variable control of the air volume advantageous if the setting device has a controllable actuator is adjustable.

So far, with regard to the adjustability of the nozzle no further details were given either. So looks an advantageous one Embodiment before that the nozzle is a return nozzle is.

Such a return nozzle is particularly easy to do adjust that this is an adjustable return valve is assigned, which enables the return of the return nozzle variably adjustable and thus also that of the Adjust the amount of fuel dispensed from the nozzle.

In the simplest case, the return valve is designed that with this different amounts of fuel of the fuel jet are permanently adjustable. It is even more advantageous however, if the return valve is continuously adjustable is so that continuous adjustment and adjustment the amount of fuel is possible.

Especially when the amount of fuel is controlled should, it is advantageously provided that the return valve is adjustable by means of an actuator.

A particularly advantageous embodiment of the invention Solution provides that the burner has a control with which the amount of fuel and the amount of air of the combustion air flow are adjustable. With such a Control can be a simple optimal setting of both the amount of fuel and the Amount of combustion air, especially with regard to a stoichiometric or near stoichiometric combustion, to reach.

It is preferably provided that the control the Actuator of the return valve controls.

Alternatively or in addition, it is advantageous if the Control controls the actuator of the setting device.

In the case of activation, only one of the two actuators it is conceivable to adjust the amount of fuel or Air quantity, or vice versa, to be specified and over the Actuator for the other size a fine adjustment to make. However, it is particularly advantageous if the controller is both the actuator of the return valve as well as the actuator of the adjusting device controls.

It is also advantageous, in particular for a complete one Ensure combustion of the fuel when the control associated with a complete combustion sensing probe is.

So there is also the possibility that the control the amount of air and the amount of fuel corresponding to one stoichiometric or near stoichiometric combustion sets.

With regard to the specification of the burner output, please provide a controller according to the invention also several Possibilities conceivable. This is an advantageous embodiment before that control burner outputs fixed can be specified. Alternatively, it is conceivable that the Control burner outputs can be variably specified.

A particularly advantageous embodiment provides that the controller according to a predetermined performance The amount of fuel and the amount of air correspond on the one hand to this Performance and on the other hand in terms of a stoichiometric or near-stoichiometric combustion.

In connection with the exemplary embodiments according to the invention So far it has been assumed that the adjustability the amount of fuel through the nozzle through a and the same nozzle is possible.

Alternatively, see an advantageous embodiment before that the amount of fuel is adjustable in that the Burner as a kit that can be used in the same burner housing different nozzles is formed. The setting the amount of fuel takes place in that the appropriate nozzle is inserted into the burner.

It is preferably provided that the nozzles are all in the essentially the same spray pattern and especially one in have substantially the same outer contour on the air flow side and just deliver different amounts of fuel.

It also provides an advantageous embodiment the adjustment of the amount of air before that the amount of air such adjustable that the burner as a kit with in the same Burner housing with replaceable insert parts the amount of air of the combustion air flow is formed. By the Providing the different adjustment parts is therefore one Adjustment of the combustion air flow possible.

It is particularly advantageous if using the adjustment parts the local entry of the combustion air flow into the combustion chamber is also adjustable.

It is preferably provided that all adjustment parts at least a partial flow of the combustion air flow can be set is.

It is particularly expedient if the inflow location of the Partial flows is the same for all setting parts.

A particularly advantageous embodiment provides that with the adjustment parts the fuel stream close to the fuel jet is constant while the recirculation stabilizing Partial flow with different setting parts different values can be set.

Regarding the constructive solution, one is special advantageous embodiment provided that the kit an identical burner housing for all burner outputs includes.

In particular, it is provided that the kit for everyone Burner performance includes an identical fan.

It is also advantageous if the kit is identical Combustion chamber includes.

Finally, it is advantageous if the kit is available for all Burner performance includes an identical nozzle assembly.

Further features and advantages of the solution according to the invention are the subject of the following description and the graphical representation of some embodiments.

Fig. 1

einen Längsschnitt durch ein erstes Ausführungsbeispiel eines erfindungsgemäßen Brenners;

Fig. 2

einen ausschnittsweisen Längsschnitt durch eine Düse des erfindungsgemäßen Brenners;

Fig. 3

eine vergrößerte Darstellung eines Frontbereichs der Düse gemäß Fig. 2;

Fig. 4

einen Schnitt längs Linie IV-IV in Fig. 3;

Fig. 5

einen Schnitt längs Linie V-V in Fig. 1 bei maximalem oder auf null reduziertem rezirkulationsstabilisierendem Teilstrom mit teilweise weggebrochener Einstellscheibe;

Fig. 6

einen Schnitt wie in Fig. 5 bei reduziertem rezirkulationsstabilisierendem Teilstrom mit teilweise weggebrochener Einstellscheibe;

Fig. 7

einen Schnitt wie in Fig. 5 bei minimalem rezirkulationsstabilisierendem Teilstrom;

Fig. 8

eine perspektivische Darstellung der Verhältnisse in der Brennkammer bei teilweise weggebrochenem Flammrohr;

Fig. 9

eine vergrößerte ausschnittsweise Darstellung des in Fig. 1 gezeigten Schnitts im Bereich der Blende, bei maximalem rezirkulationsstabilisierendem Teilstrom in der oberen und auf null reduziertem minimalem rezirkulationsstabilisierendem Teilstrom in der unteren Hälfte;

Fig. 10

einen Schnitt ähnlich Fig. 1 eines zweiten Ausführungsbeispiels des erfindungsgemäßen Brenners;

Fig. 11

einen Schnitt ähnlich Fig. 1 eines dritten Ausführungsbeispiels des erfindungsgemäßen Brenners;

Fig. 12

einen Schnitt ähnliche Fig. 1 eines vierten Ausführungsbeispiels;

Fig. 13

einen Schnitt ähnlich Fig. 1 eines fünften Ausführungsbeispiels;

Fig. 14

einen Schnitt ähnlich Fig. 1 eines sechsten Ausführungsbeispiels des erfindungsgemäßen Brenners;

Fig. 15

einen Schnitt längs Linie XII-XII in Fig. 14 bei maximalem rezirkulationsstabilisierendem Teilstrom und der zur Einstellung desselben vorgesehenen Blende;

Fig. 16

einen Schnitt wie in Fig. 15 bei eingesetzter Blende für einen reduzierten rezirkulationsstabilisierenden Teilstrom; und

Fig. 17

einen Schnitt wie in Fig. 15 bei eingesetzter Blende für den minimalen, auf Null reduzierten rezirkulationsstabilisierenden Teilstrom.

The drawing shows:

Fig. 1

a longitudinal section through a first embodiment of a burner according to the invention;

Fig. 2

a fragmentary longitudinal section through a nozzle of the burner according to the invention;

Fig. 3

an enlarged view of a front portion of the nozzle of FIG. 2;

Fig. 4

a section along line IV-IV in Fig. 3;

Fig. 5

a section along line VV in Figure 1 at maximum or reduced to zero recirculation-stabilizing partial flow with partially broken shim.

Fig. 6

a section as in Figure 5 with reduced recirculation-stabilizing partial flow with partially broken shim.

Fig. 7

a section as in Figure 5 with minimal recirculation-stabilizing partial flow.

Fig. 8

a perspective view of the conditions in the combustion chamber with the flame tube partially broken away;

Fig. 9

an enlarged fragmentary representation of the section shown in Figure 1 in the area of the orifice, with maximum recirculation-stabilizing partial flow in the upper and reduced to zero minimal recirculation-stabilizing partial flow in the lower half.

Fig. 10

a section similar to Figure 1 of a second embodiment of the burner according to the invention.

Fig. 11

a section similar to Figure 1 of a third embodiment of the burner according to the invention.

Fig. 12

a section similar to Figure 1 of a fourth embodiment.

Fig. 13

a section similar to Figure 1 of a fifth embodiment.

Fig. 14

a section similar to Figure 1 of a sixth embodiment of the burner according to the invention.

Fig. 15

a section along line XII-XII in Figure 14 with maximum recirculation-stabilizing partial flow and the aperture provided for adjusting the same.

Fig. 16

a section as in Figure 15 with the aperture used for a reduced recirculation-stabilizing partial flow. and

Fig. 17

a section as in Fig. 15 with the aperture used for the minimum, reduced to zero recirculation-stabilizing partial flow.

A first embodiment of an inventive Brenners, shown in Fig. 1, comprises one as a whole with 10th designated burner housing with a support tube 12 and a to this adjoining flame tube 14.

In the support tube 12 is in an opposite of the flame tube End region of a fan designated as a whole with 16 arranged, which has a fan drive 18 and a fan wheel 20 includes. This fan 16 produces a Support tube 12 passing through air flow 22, which in the direction of the flame tube 14 flows.

Furthermore, one is designated as a whole by 24 in the support tube 12 Nozzle block arranged, which is a nozzle holder 26 with a screwed into this nozzle 28. The Nozzle 28 is described in detail below Return nozzle is formed and is via a nozzle feed 30 supplied with liquid fuel, in particular oil, while a part of the fuel supplied in the nozzle feed line 30 again flows back, throttling the return via an in adjustable return valve arranged in the nozzle return line 32 34 is possible.

The feeding of the fuel into the nozzle feed line 30 takes place via a fuel feed pump 36, which is preferably is also driven by the drive 18 of the blower 16, in particular on the same shaft as the impeller 20. This fuel feed pump 36 is via a pump feed line 38 is fueled and also has a return line 40 connected in which excess fuel flows back from the fuel feed pump 36. In these Return line 40 also opens the nozzle return line 32 after the return valve 34.

2, 3 and 4, the nozzle 28 includes one Nozzle head 50, which in turn rests on a nozzle body 52 is screwed on, and receives a swirl body 54.

The nozzle head 50 in turn is also still in the nozzle carrier 26 screwed so that the nozzle body 52 in one Recess 56 of the nozzle carrier 26 is located, the recess 56 forms a fuel supply area 58, which with the Nozzle feed line 30 is connected and a return area 60, which is connected to the nozzle return line 32.

The fuel entering the fuel supply area 58 preferably flows through a filter 62 and then overflows two opposite inlet channels 64 of the nozzle body 52 in further inlet channels 66 in the swirl body 54 and of these, as shown in Fig. 3, in an annular Inlet space 68 of the swirl body 54, which by a support plate closing the swirl body 54 on the end face 70 is closed. From the annular inlet space 68 the fuel enters swirl channels 72 lying radially within the annular inlet space 68 Swirl chamber 74, in which there is a corresponding to the orientation of the swirl channels 72 forms circumferential swirl flow and the fuel passes from this swirl chamber 72 an annular circumferential gap 76 in a spray hole 78, from which a conical fuel jet 80 exit.

The spray bore 78 is opposite in the swirl body 54 a return channel 82 is arranged which the swirl body 54 passes through and arranged in a nozzle body 52 Return channel 84 merges, which then finally in the return area 60 of the recess 56 opens, which then in turn in connection with the nozzle return line 32 stands.

Further details of the nozzle 28 used according to the invention result from the German patent 42 15 122, to which full reference is made in this connection.

The nozzle assembly 24 together with the nozzle 28 is within the Support tube 12 arranged in a prechamber 48, which also is penetrated by the air flow 22.

The antechamber 48 is closed off by one as a whole 90 designated and inserted into the support tube 12, on which is located downstream of the nozzle 28 a combustion chamber 92 connects, which is surrounded by the flame tube 14. Also the flame tube 14 is preferably held on the support tube 12.

The aperture 90 is arranged so that the spray bore 78th with a nozzle opening near or in plane 89 of the Aperture 90 is located and the fuel jet emerging at the nozzle 28 80 essentially completely in the combustion chamber 92 spreads.

For this purpose, the aperture 90 is coaxial with the longitudinal axis 86 the inflow opening 94 arranged in the nozzle 28. The Inflow opening 94 is also chosen so large that between an edge 96 of the inflow opening 94 and one of this edge 96 facing outside 98 of the nozzle head 50 an annular Passage 100 remains through which a fuel jet near Partial stream 102 of a total of 48 from the prechamber the combustion air flow flowing through the combustion chamber 92 passes through.

In order to reduce the flow velocity in the partial flow 102, is the edge 96 of the inflow opening 94 with a Vortex edge 104 provided, which for vortex formation in the partial flow 102 leads and for example by a step-shaped Cross-sectional constriction of the inflow opening 94 is formed.

Another partial flow 106 of the from the pre-chamber 48 in the Combustion chamber 92 entering combustion air flow passes through radially outside the inflow opening 94 in an annular region 108 arranged openings 110 through which a pitch circle 109, preferably at equal angular intervals and with spaces 111 around the center of the annulus area 108 are arranged.

The openings 110 preferably have a reference to the pitch circle 109 an extension in the azimuthal direction which one Corresponds to an angle which is approximately one to two times the the extent of the spaces 111 corresponding angle is.

The openings 110 can, however, overlap in the azimuthal direction extend an angle that is about 0.1 to about 8 times the angle of the extension of the gaps 111 corresponds.

The openings 110 are arranged so that the partial flow 106 of the combustion air flow through the spaces 111 between the openings 110 in the form of a circumferential direction interrupted ring flow corresponding flow pattern in the combustion chamber 92 enters and thus the training an inner recirculation flow 112 and also one external recirculation flow 119 in the combustion chamber 92 stabilized so that a flame root 114 one in the Combustion chamber 92 forming flame 116 essentially in is the same distance from the aperture 90, regardless of one amount of fuel carried by the fuel jet 80 and a corresponding through the partial streams 102 and 106 in the Combustion chamber 92 entering the corresponding amount of combustion air.

The flows according to the invention in the combustion chamber 92 are shown in Fig. 8, thus the fully conical Fuel jet 80 close to the cylindrical fuel jet Partial stream 102, which with a flow direction 103 enters the combustion chamber 92, which is parallel to a flow direction 79 of the fuel jet 80. Furthermore the recirculation stabilizing partial flow 106 which has a flow direction 79 parallel flow direction 107 in the form of individual flows 105 enters the combustion chamber 92, the individual flows 105 lie on a circular cylinder, the cross-section on the aperture 90 has the shape of the circular ring region 108 and defined by the pitch circle 109 lying in the middle of the jacket is.

The flame root 114 in turn joins one non-burning part 81 of the fuel jet 80, which a length of about 1 to about 4 cm, preferably about 1 to about 3 cm, on and from it spreads the flame 116, which is on one Inner wall region 15 of the flame tube 14 creates before it this leaves.

The area of the combustion chamber 92 from the aperture 90 to Inner wall area 15 on which the flame 116 forms a so-called recirculation space 91. In this flows on the one hand in the form of an internal recirculation 112 hot gas between the flame tube 14 and the partial flow 106 back in Direction to aperture 90 and in front of aperture 90 between the individual flows 105 in the direction of non-burning part 81 of the fuel jet 80 around the non-burning fuel on the way to the flame root 115 and also to heat the combustion air.

In addition occurs after arranged in the flame tube 14 after the aperture 90 outer recirculation openings 118 cold combustion gas from the respective boiler in the form of the outer Recirculation flow 119 into the recirculation space 91 close to the glare and essentially prevents contact between the hot gases of the inner recirculation flow 112 and the cold aperture 90.

The outer recirculation flow 118 also occurs close to the screen between the individual streams 105 and mixes then with the combustion air flow 102, 106 by the Increase flame tube 14 mass flow passing so far that the flame root 114 at a constant distance of at least 2 cm from the aperture 90 and thus also from the Nozzle 28 remains that the non-burning part 81 of the Fuel jet 90 is long enough to drop the oil droplets in to evaporate it almost completely.

Preferably the sum of the areas is that for entry the combustion air flow into the openings provided in the combustion chamber, in particular the sum of the area openings 110 and the inflow opening 94, dimensioned so that they are approximately at most the sum of the areas of the recirculation openings for the external recirculation, especially the sum of the areas of the formed as elongated slots in the circumferential direction outer recirculation openings 118 corresponds.

The ratio of the area of the recirculation openings 118 to The area of the central inflow opening 94 is between approximately 0.3 to about 19.2, preferably between about 0.9 and 5.1. The recirculation chamber 91 then closes the Flammraum 117 on.

The first one shown in FIGS. 1 to 9 is preferred Embodiment of the partial stream 102 near the fuel jet trained that this at the smallest burner output corresponding recirculation flow without the recirculation stabilizing Partial stream 106 stabilized (FIG. 9 lower half) and then for large burner capacities Recirculation-stabilizing partial flow 106 stabilization takes over (Fig. 9 upper half) that the near fuel jet Partial stream 102 can no longer afford.

If the burner is dimensioned differently, it is also possible to at the lowest power, both near the fuel jet Stream 102 and a minimal recirculation stabilizing Provide partial stream 106.

Such a stabilization of the recirculation flows 112 and 119 can be reached in particular if, for example corresponding to the inner diameter of the flame tube Outside diameter of the recirculation chamber 91 of the combustion chamber 92 about 1.5 to about 3.9 times, yet better about two to three times the diameter of a partial circle 109 of the circular ring region 108 It is more advantageous if the inner diameter of the recirculation space 91 of the combustion chamber 92 which is approximately 2.2 to about 2.6 times, better still about 2.2 to about 2.5 times the diameter of the pitch circle 109.

The ratio of the diameter of the pitch circle 109 to The diameter of the central inflow opening 94 is between about 1.0 and about 4.2, preferably about 2.6 to about 4.0, more preferably about 2.8 to about 3.5, and preferably between about 1.82 and about 2.0.

In addition, it is advantageous if the central inflow opening 94 is dimensioned so that an outer diameter of the recirculation chamber 91 of the combustion chamber 92 about 3.4 to about 8.5 times, better still about that 4 to 6 times, better still about 4.4 to approximately 5.9 times the diameter of the central inflow opening 94 is.

The diameter ratios at which the invention adjustable blue burners in all performance ranges works are summarized in Table I, the Corresponding outer diameter of the recirculation space 91 Inner diameter of the flame tube with "flame tube (14)", the Diameter of the pitch circle with "pitch circle (109)" and the Diameter of the inflow opening with "inflow opening (94)" are designated.

Preferred ranges of diameter ratios, staggered after individual burner outputs, Table II shows, the Burner with these diameter ratios with low Emissions works. Optimal emission values are approximate with the diameter ratios given in Tables III and IV available.

To adjust the combustion air volume of the combustion air flow different burner capacities is one as a whole 120 designated adjustment device is provided, which, like shown in Fig. 5 to 7, an annular Includes shim 122, which with the openings 110 identical openings 124, which also in the same angular distances as and in the openings 110 radial distance from a center of the annulus area 108 are arranged. Annular shim 122 is in turn, as shown enlarged in Fig. 9, in a cylindrical disk-shaped provided in the aperture 90 Well 126, which is open to the antechamber 48. The rotatable guidance of the shim takes place over the Storage of the same with its outer edge 128 on one cylindrical edge 130 of depression 126.

The shim 122 is adjustable so that, as in 5 to 7, either openings 124 are congruent with the openings 110, so that the maximum cross section for the individual openings 110 replacing partial flow 106 is available, or rotatable so that the openings 124 are no longer congruent the openings 110 and only the overlapping one another Areas of openings 110 and 124 the partial flow 106 pass so that the air volume of the partial flow 106th is reduced, as shown in Fig. 6. The partial stream 106 can, as shown in Fig. 7, be completely interrupted, namely, if the openings 124 on the gap between the Openings 110 are available.

To rotate the shim 122, this is in one Provide partial area of its outer edge with teeth 132, in which a toothing 134 as a whole with 136 designated setting pinion of the setting device 120 intervenes. This setting pinion is in turn rotatable the aperture 90 stored, and in the simplest case in one another cylindrical bearing recess 138 in the aperture 90 stored, the rotatable bearing by the concern the teeth 134 on cylindrical wall surfaces 140 of the Storage deepening 138 takes place. The deepening of the warehouse opens 138 to the antechamber 48.

Both the shim 122 and the pinion 136 are in their respective recesses 126 and 138 through 9 fixing elements not shown in the drawing held so that they each bottom on the wells issue.

In the case of the first embodiment, the setting pinion 136, for example, self-locking in the storage recess 138 stored and for example with a slot 142 provided, which makes it possible with a conventional screwdriver to turn the setting pinion 136 so that adjustment of the shims 122 is also possible, the respective settings of the shims 122 maintained by the self-locking adjustment pinion 136 become.

The first embodiment now works so that interrupted partial flow 106 as the amount of combustion air only from the partial flow 102 through the passage 100 into the combustion chamber 92 incoming combustion air is available. Corresponding this amount of air is adjusted by the nozzle 28th amount of fuel dispensed into the fuel jet 80, where the amount of fuel is adjusted so that the flame 116 blue burns and a stoichiometric or near stoichiometric Combustion sets. This setting the amount of fuel takes place via the setting of the return valve 34 and thus via the nozzle return line 32 in the Return line 40 from the fuel stream returning from the nozzle 28.

For larger capacities, you can adjust the shim 122 in addition to the partial stream close to the fuel jet 102 of the combustion air flow contribute to the partial flow 106, wherein this partial flow 106 at higher burner capacities Recirculation flow 112 additionally stabilized. At maximum The amount of combustion air in partial flow 106 represents the entry of the combustion air flow from the pre-chamber 48 into the combustion chamber 92 approximately 5 times the cross-sectional area is available as with partial flow 106 completely prevented.

An adjustment of the nozzle 28 into the fuel jet 80 amount of fuel dispensed takes place through the already mentioned setting of the return valve 34 with corresponding Throttling of the return from the nozzle 28 Fuel.

With all power settings of the invention Brenner is a distance from the flame root 114 of the flame 116 of aperture 90 is substantially constant and it is at all burner power settings a blue burn the Flame 116 with essentially stoichiometric or Near stoichiometric combustion adjustable.

In a second embodiment of the invention Brenners, shown in Fig. 10, are those parts that are identical to the first embodiment, with the same Provide reference numerals. Regarding the description these parts can therefore refer to the explanations of the first embodiment full reference is made.

In contrast to the first embodiment, which none additional flow guide elements in the combustion chamber 92, is in the second embodiment Flow guide ring 150 is provided, which is at a distance of the aperture 90 is arranged, and with its front edge 152 up to a maximum of a quarter of a distance between the aperture 90 and the foot portion 114 of the flame 116 extends. Furthermore, the flow guide ring 150 with a the rear edge 154 facing the panel 90 at a distance from the Aperture 90 arranged so that the recirculation flow 112 between that in the edge 154 and a front face 156 of the Aperture 90 from the side of the aperture 90 in the flow guide ring 150 can occur. The Flow ring 150 also serves as an additional one Stabilizing the recirculation flow 112, wherein a significant distance between the leading edge 152 and the foot portion 114 of the flame 116 is required to different power settings of the invention Brenners the formation of a strong recirculation flow 112 to ensure and the effect of the recirculation stabilizing Support substream 106.

The flow guide ring 150 is preferably with webs 158 held at the aperture 90.

In a third embodiment of an inventive Brenners, shown in Fig. 11, are those parts that are identical to the first embodiment, with provided with the same reference number, so that with regard to the Description of these parts also in full on the Execution referred to the first embodiment can be. In contrast to the first embodiment here an actuator for setting the return valve 34 160 provided and for the adjustment of the setting pinion 136 an actuator 162, both of which have a common control 164 can be controlled.

This controller 164 has power settings via an input 166 built the burner according to the invention, wherein controller 164 for each input power setting 166 the corresponding setting of Return valve 34 and the actuator 162 of the adjusting device 120 makes. For example, this is in a memory of the controller 164 predeterminable positions the actuators 160 and 162 can be carried out.

To additionally ensure that flame 116 is blue-burning Flame the fuel stoichiometrically or burns close to stoichiometric is an additional one Lambda probe 168 arranged in the exhaust gas flow of flame 116, which is also connected to the controller 164 so that the controller 164 after rough settings of the power the actuators 160 and 162 are additionally capable is a fine adjustment of either the amount of combustion air or the amount of fuel to make stoichiometric or to comply with near stoichiometric combustion conditions.

The controller 164 is constructed in the simplest case so that via an adjuster, for example manually, each desired performance of the burner according to the invention adjustable are.

In an improved embodiment of the third embodiment is the controller 164 designed so that overall control of a system, for example a heating system, into which the burner according to the invention is integrated is a requirement for the required performance of the burner according to the invention takes place so that the controller 164 then depending on the requested performance of the invention Brenner adjusts the actuators 160 and 162 accordingly and a fine adjustment based on the measured values of the Lambda probe 168 carries out.

In a fourth embodiment, shown in Fig. 12, are those parts with the above embodiments are identical, with the same reference numerals provided so that with regard to their description on the statements full reference to these exemplary embodiments is taken.

In contrast to the previous exemplary embodiments, this is Flame tube 14 in the area of the recirculation space 91 following flame chamber 117 radially along its length to front end 170 narrowed so that the inner wall portion 15 to which the flame 116 is already applied radially inward is.

This flame tube allows, especially with small burner outputs, preferably less than 20 kW, stable in the flame tube 14 standing flame 116 to get. Also prevented this geometry an undesired intake of smoke gases from the front end of the flame tube 14.

In a fifth embodiment, shown in Fig. 13, in the same way as in the fourth embodiment, with respect to those with the same reference numerals Parts referenced above.

In contrast to the previous exemplary embodiments closing the openings 110 by means of conical plugs 172 which is held on rods 174 and in the axial direction of the Support tube 12 movable via a guide 176 on the nozzle assembly 24 are guided in the support tube 12. Depending on how far the protruding conical plug 172 into the openings 110 a reduction in the cross-sectional area of each opening 110 possible.

In a sixth embodiment of an inventive Brenners, shown in Fig. 14, are those Parts with those of the first embodiment are identical, provided with the same reference numerals, so that with regard to these parts also on the explanations for first embodiment referred to in full can be.

In contrast to the first embodiment, the sixth embodiment, shown in FIGS. 14 to 17, a power setting is also possible, however in this embodiment, the burner according to the invention built in the form of a kit. Instead of one as a return nozzle trained nozzle 28 with a nozzle return line 32 and a return valve 34 provided therein Adjusting the fuel flow are a set of several Nozzles 228 are provided, each having the same spray pattern and the same airflow side Outer contour and therefore the same shape of the fuel jet 80, but deliver with different amounts of fuel. In these nozzles 228, the fuel is supplied via the Fuel feed pump 36 and the nozzle feed line 30, one Nozzle return line 32 is however unnecessary.

The different nozzles 228 correspond to each other different performances of the burner according to the invention.

To adapt the combustion air flow to the different ones Amounts of fuel from the different nozzles 228 are several Apertures 290a to 290c are provided, the aperture 290a of the the largest amount of fuel emitting nozzle 228, the orifice 290c assigned to the nozzle delivering the smallest amount of fuel and the aperture 290 b is assigned to a nozzle 228 is the amount of fuel between the maximum and the minimum amount of fuel.

The diaphragms 290a to c differ in cross section of the openings 210 provided for the partial flow 106, not however, in terms of their location, the openings 210a with the openings 110 with respect to the overall cross section of the Openings are identical, while openings 210b are one Overall cross section showing which one intermediate setting, for example shown in Fig. 6, and thus also an intermediate output of the corresponding nozzle 228 the aperture 290c, the openings 210 are completely absent, so that this the position of the adjusting device shown in FIG. 7 120 corresponds in which the partial flow 106 completely is prevented and the combustion air flow only through the Partial stream 102 is formed.

Depending on the nozzle 228 mounted in the nozzle assembly 24, one of the Install panels 290a to 290c in the support tube 12, wherein in the fourth embodiment, the panels 190 are removable are held in the support tube. This is for example on the nozzle assembly 24 by means of a retaining ring 292 Tripod 294 held, which the respective aperture 290 their side facing the antechamber 48 296 and this against a sealing ring 298 in the direction of the flame tube 14 presses. The nozzle assembly 26 as a whole is in Movable in the direction of a longitudinal axis 300 of the support tube 12 and with a spring not shown in Fig. 14 in the direction of the flame tube 12 is applied. So it's taking out the diaphragm 290 in the direction of the antechamber 48 is possible, while the aperture 290 in the direction of the flame tube 14 through the abutment formed for example as a sealing ring 298 is fixed.

Furthermore, in the same way as is preferably shown in connection with the first exemplary embodiment, the combustion chamber 92 is designed free of mechanical flow guiding elements, so that when the nozzle 228 corresponding to the respective output and the respective orifice 290 are installed, the suitable recirculation flow 112 is also formed in a stable manner is guaranteed and is also ensured that the flame 116 provides a stoichiometric or near-stoichiometric combustion as a blue-burning flame. Furthermore, a function corresponding to the first exemplary embodiment is ensured by the cross sections of the openings 210 correspondingly provided for the partial flow 106. power 1 Pitch circle (109
Inflow opening (94) 1.0 - 4.2 2nd Flame tube (14)
Pitch circle (109) 1.7 - 3.9 3rd Flame tube (14)
Inflow opening (94) 3.4 - 8.5 4th Slot surface (118)
Inflow opening (94) 0.3 - 19.2

Claims (52)

Comprehensive burner for liquid media a burner housing (10) which has a support tube (12) and an adjoining flame tube (14), a nozzle assembly (24) arranged in the support tube (12) in a prechamber (48) with a nozzle (28) generating a fuel jet (80), an essentially mixing tube-free combustion chamber (92) arranged in the flame tube (14) and in which the fuel jet (80) spreads, a separating element (90) between the prechamber (48) and the combustion chamber (92) with a central opening (94) through which the fuel jet (80) passes, a fan (16) for generating a combustion air flow entering the combustion chamber (92), which comprises a partial flow (102) close to the fuel jet, wherein in the combustion chamber (92) the fuel burns with a blue-burning flame (116) essentially stoichiometrically or near-stoichiometrically,
characterized in that, in addition to the partial stream (102) close to the fuel jet, a recirculation-stabilizing partial stream (106) of combustion air enters the combustion chamber (92), which comprises individual streams (105) lying radially outside at a defined distance from the partial stream (102) near the fuel jet, that in the Combustion chamber (92) forms an internal recirculation flow (112) which runs back from the blue-burning flame (116) to the non-burning part (81) of the fuel jet (80) and that the recirculation-stabilizing partial flow (106) of the combustion air stabilizes the internal recirculation flow (112). Burner according to the preamble of claim 1 or according to Claim 1, characterized in that in the burner housing Openings (118) are provided through which an external recirculation flow carrying cold combustion gases (119) enters the combustion chamber (92), that the outer recirculation flow (119) near the Separating element (90) enters the combustion chamber (92) and is so large that a flame root (114) of the blue-burning Flame (116) a distance of at least 1 cm from the nozzle (28), and that between the nozzle (28) and the flame root (114) a non-burning Part (81) of the fuel jet (80) under Addition of combustion air (102, 106) spreads out conically. Burner according to the preamble of claim 1 or according to Claim 1 or Claim 2, characterized in that openings (118) are provided in the burner housing (10), through which an external cold combustion gas leading recirculation flow (119) into the combustion chamber (92) the outer recirculation flow occurs (119) near the separating element (90) in the Combustion chamber (92) occurs and that this is an inner Recirculation flow (112) opposite the separating element (90) shields, which turns out to be in the combustion chamber (92) from the blue-burning flame (116) to the non-burning one Part (81) of the fuel jet (80) extending back Current forms. Burner according to one of the preceding claims characterized that the internal recirculation flow (112) from the flame (116) on the inside of the flame tube (14) in the direction of the separating element (90) flows. Burner according to one of the preceding claims, characterized in that the internal recirculation flow (112) is burning yellow. Burner according to one of the preceding claims, characterized in that the internal recirculation flow (112) by the recirculation stabilizing Partial stream (106) passes through. Burner according to one of the preceding claims, characterized characterized that the recirculation stabilizing Partial stream (106) substantially parallel to Flow direction (79) of the fuel jet (80) in the combustion chamber (92) enters. Burner according to one of the preceding claims, characterized characterized in that the partial streams (102, 106) regardless of the set air volume enter the combustion chamber (92) at the same location. Burner according to claim 8, characterized in that to adjust the air volume at least one of the Partial flows (102, 106) to adapt to the amount of fuel is adjustable. Burner according to claim 9, characterized in that the recirculation-stabilizing partial flow (106) with regard to the air volume is adjustable. Burner according to claim 10, characterized in that the amount of air in the recirculation-stabilizing partial flow (106) maximum at maximum fuel quantity and is minimal with a minimal amount of fuel. Burner according to one of the preceding claims, characterized characterized in that the amount of air in the near fuel jet Partial flow (102) with all settings the amount of fuel is constant. Burner according to one of the preceding claims, characterized characterized in that the fuel jet (80) a coherent nozzle opening emanating from the cone forms. Burner according to one of the preceding claims, characterized characterized that the near fuel jet Partial stream (102) substantially parallel to the direction of flow (79) of the fuel jet (80) in the Combustion chamber (92) enters. Burner according to one of the preceding claims, characterized characterized that the near fuel jet Partial stream (102) flowing around the fuel jet (80) in the combustion chamber (92) enters. Burner according to claim 15, characterized in that the partial stream (102) near the fuel jet in the area of a circumference of a nozzle head (50) of the nozzle (28, 228) flows into the combustion chamber (92). Burner according to claim 16, characterized in that the partial stream (102) near the fuel jet along a defined outer contour (98) of the nozzle head (50) flows. Burner according to claim 15, characterized in that the partial stream (102) close to the fuel jet and the fuel jet (80) through the same central inflow opening (94) enter the combustion chamber (92). Burner according to claim 18, characterized in that the partial stream (102) near the fuel jet through a Passage (100) between the nozzle head (28, 228) and one edge for the sub-stream close to the fuel jet (102) provided inflow opening (94) into the Combustion chamber (92) flows. Burner according to claim 18 or 19, characterized in that the inflow opening (94) for the near fuel jet Partial stream (102) generating turbulence is trained. Burner according to claim 20, characterized in that the inflow opening (94) with a swirl edge (104) is provided. Burner according to one of the preceding claims, characterized characterized that the total combustion air flow (102, 106) through an antechamber (48) is. Burner according to claim 22, characterized in that the combustion air flow (102, 106) through a separating element (90) enters the combustion chamber (92). Burner according to claim 23, characterized in that the separating element (90, 290) faces the nozzle (28, 228) Inflow opening (94) for the fuel jet near Has partial stream (102). Burner according to one of claims 22 to 24, characterized in that that the separating element (90, 290) relative to the inflow opening (94) for the near fuel jet Partial stream (102) at least one radially outer Opening (110, 210) for the recirculation stabilizing Has partial stream (106). Burner according to one of the preceding claims, characterized characterized in that the combustion chamber (92) itself extending from a plane (89) which is close the plane of the nozzle opening. Burner according to one of the preceding claims, characterized characterized in that the combustion chamber (92) between the separating element (90) and the area of the flame root (114) has a substantially constant cross section. Burner according to one of the preceding claims, characterized characterized in that the separating element (90) a Aperture is. Burner according to one of the preceding claims, characterized characterized in that the aperture (90) in one Level (89) extends. Burner according to one of the preceding claims, characterized characterized in that the combustion chamber (92) has a from the non-burning part (81) of the fuel jet (80) penetrate and extend around it Has recirculation space (91). Burner according to claim 30, characterized in that the recirculation space (91) extends at least up to Flame root (114) extends. Burner according to one of claims 30 or 31, characterized characterized that the recirculation stabilizing Partial stream (106) enters the recirculation space (91). Burner according to one of the preceding claims, characterized characterized that the recirculation stabilizing Partial stream (106) symmetrical to an axis of symmetry the combustion chamber (92) is formed. Burner according to one of the preceding claims, characterized characterized that the recirculation stabilizing Partial flow (106) in the form of a on a cylinder lying current image (105) into the combustion chamber (92) entry. Burner according to claim 34, characterized in that the current pattern from parallel component streams (105) is composed. Burner according to claim 35, characterized in that the individual streams (105) at a constant angular distance (111) are arranged to each other. Burner according to claim 36, characterized in that the ratio of the angular distance (111) between two Part streams (105) to the angular width of the inlet cross-section (110) each item stream (105) is between about 10 and about 0.1. Burner according to claim 37, characterized in that the ratio of the angular distance (111) between two Part streams (105) to the angular width of the inlet cross-section (110) each item stream (105) is between about 1.5 and 0.1. Burner according to claim 38, characterized in that the ratio of the angular distance (111) between two Part streams (105) to the angular width of the inlet cross-section (110) each item stream (105) is in the range of about 0.7 and 0.25. Burner according to one of claims 33 to 39, characterized in that that the cylinder is a circular cylinder which by a center circle lying in the same (109) is fixed. Burner according to claim 40, characterized in that the recirculation space (91) has an outer diameter, which is about 1.5 to about 3 times larger is the diameter of the pitch circle (109) of the Circular cylinder is. Burner according to claim 41, characterized in that the recirculation space (91) has an inner diameter which is about 2 to about 2.5 times is larger than the diameter of the pitch circle (109) of the circular cylinder. Burner according to claim 42, characterized in that the recirculation space (91) has an inner diameter which is about 2.4 times as large as that Diameter of the pitch circle (109) of the circular cylinder. Burner according to one of claims 30 to 43, characterized in that that the recirculation space (91) the flame chamber (117) connects. Burner according to claim 44, characterized in that the flame space (117) has an inner diameter, which is smaller than that of the recirculation space (91) is. Burner according to claim 45, characterized in that the inside diameter of the flame chamber (117) in the area about 0.6 to about 0.9 times the inner diameter of the recirculation space (91). Burner according to claim 46, characterized in that the inside diameter of the flame chamber (117) in the area approximately 0.8 times the inside diameter of the Recirculation space (91). Burner according to one of the preceding claims, characterized characterized in that the flame (116) one in the Combustion chamber (92) has a flame root (114). Burner according to claim 48, characterized in that the combustion chamber (92) over the flame root (114) extends beyond. Burner according to one of the preceding claims, characterized characterized that the outer recirculation flow (119) separate from the combustion air flow (102, 106) enters the combustion chamber (92). Burner according to claim 50, characterized in that the outer recirculation flow (119) through recirculation openings (118) in the flame tube (14) directly in the combustion chamber (92) enters. Burner according to one of the preceding claims, characterized characterized that an area of for entry of the combustion air flow (102, 106) into the combustion chamber (92) provided openings (94, 110) at most approximately the area of the recirculation openings provided in the flame tube (14) (118) for the external recirculation flow (119) corresponds.

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