Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
  • F23C9/006—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber the recirculation taking place in the combustion chamber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
  • F23D11/24—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space by pressurisation of the fuel before a nozzle through which it is sprayed by a substantial pressure reduction into a space
  • F23D11/26—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space by pressurisation of the fuel before a nozzle through which it is sprayed by a substantial pressure reduction into a space with provision for varying the rate at which the fuel is sprayed
  • F23D11/28—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space by pressurisation of the fuel before a nozzle through which it is sprayed by a substantial pressure reduction into a space with provision for varying the rate at which the fuel is sprayed with flow-back of fuel at the burner, e.g. using by-pass
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D11/00—Burners using a direct spraying action of liquid droplets or vaporised liquid into the combustion space
  • F23D11/36—Details, e.g. burner cooling means, noise reduction means
  • F23D11/40—Mixing tubes or chambers; Burner heads
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
  • F23C2202/00—Fluegas recirculation
  • F23C2202/40—Inducing local whirls around flame

Definitions

• the invention relates to a burner for liquid or gaseous fuels, comprising a burner housing, a nozzle assembly arranged in the burner housing with a nozzle generating a fuel jet, a combustion chamber in which the fuel jet spreads, a blower for generating a combustion air flow entering the combustion chamber, wherein A flame that burns blue due to a stable recirculation flow can be generated in the combustion chamber from the fuel jet and the combustion air flow.
• DE-OS 40 09 222 discloses a burner for the stoichiometric combustion of liquid or gaseous fuels from an atomizer nozzle. In this burner, air is led around the atomizer nozzle through an orifice into a combustion chamber into which the fuel emerging from the nozzle also enters.
• EP-A-0 430 011 also discloses a blue-burning burner in which a mixture of fresh air and recirculating combustion gases are supplied and mixed around an atomizer nozzle before they again lead to stoichiometric combustion with the fuel coming from the atomizer nozzle.
• the combustion air and recirculating combustion gas are mixed in front of the plane in which an orifice of the nozzle is located, and after this in a mixing chamber the combustion air and the recirculating combustion gases are mixed with the fuel, which then enter the actual combustion chamber.
• the supply of fresh air is divided, on the one hand into a first part, which mixes directly with the recirculating combustion gases, and, on the other hand, into a second part, which flows around the atomizer nozzle and serves to cool the atomizer nozzle, so that the cooling of the Atomizer nozzle, especially the oil nozzle, is adjustable.
• This fresh air is then also mixed in a mixing chamber with the remaining fresh air and the recirculating combustion gas and the fuel.
• a controllable burner is known from DE-OS 27 12 564, in which a baffle plate is present and a vacuum region is created downstream of the baffle plate by generating a rotating hollow air column, so that Combustion gases are sucked back into this vacuum area.
• the rotating hollow air column is generated by radial slots running in the radial direction and covered with scoops.
• the atomizer nozzle with the ignition electrodes is arranged in a closed space, which is only so much
• Fresh air is supplied as required to move the spark.
• DE-PS 29 08 427 discloses a burner in which, with the addition of flue gases, a substoichiometric combustion takes place in a primary combustion zone, with a direct supply of a jacket air stream enveloping the fuel flow, and then in a superstoichiometric secondary combustion zone, in the residual air over the circumferential area primary combustion zone is fed, further combustion takes place.
• the residual air is fed coaxially around the respective burner in at least two partial flows, which reach the flame from the burner mouth after a certain free flow path.
• a so-called blue burner is known, in which internal recirculation is forced through a mixing tube, the fuel jet emerging from an atomizer nozzle being supplied on the one hand with this directly surrounding combustion air and on the other hand, further air passage bores are provided radially on the outside, but these are lie radially inside the mixing tube.
• a burner with a recirculation is known from EP-A-0 538 761, in which the external recirculation is generated by a longitudinal direction of the slots, these slots extending with their longitudinal direction in the circumferential direction.
• a so-called mixing tube is required to form a stable recirculation flow, which defines a single recirculation flow of hot gas and thus enables the flame to burn blue.
• this flame burns a substantially completely gasified fuel, which in particular when using oil as fuel makes it necessary that the small oil droplets initially emerging from the nozzle into the fuel jet until combustion by the flame in the to evaporate substantially completely.
• the invention is therefore based on the object
• This object is achieved according to the invention in a burner of the type described in the introduction in that the burner can be set to different burner outputs in that the nozzle can be set with respect to the amount of fuel forming the fuel jet, that the combustion air flow entering the combustion chamber corresponds to an essentially complete combustion of the Fuel jet is adjustable in terms of its amount of air that the
• Combustion chamber is designed so that it is training allows different recirculation flows and that the combustion air flow enters the combustion chamber locally relative to the fuel jet in such a way that this stabilizes the recirculation flow producing a blue-burning flame with each adjustment of the air quantity and fuel quantity.
• combustion air flow enters the combustion chamber in the form of a partial flow close to the fuel jet and in the form of a partial flow lying radially outward with respect to the partial close to the fuel jet at a defined distance.
• This division of the combustion air flow according to the invention creates an advantageous possibility to stabilize the formation of the recirculation flow in the respective setting of fuel quantity and air quantity.
• the stabilization of the recirculation flow can be achieved particularly advantageously with the simplest means with each setting of the fuel quantity and air quantity.
• the recirculation-stabilizing partial flow can be adjusted with regard to the air quantity.
• the adjustability of the recirculation-stabilizing partial flow can be used in particular to achieve an advantageous stabilization of the recirculation flow for each burner output, since this partial flow acts directly on the formation of the recirculation flows and thus an adjustment of the same can be carried out in such a way that the recirculation flow due to the local entry of this partial flow is stabilizable in the combustion chamber.
• the recirculation-stabilizing partial stream preferably enters the combustion chamber in the form of a ring stream interrupted in the circumferential direction around its fuel jet, as a result of which the stabilization of the recirculation flow is further improved, since a "flow" of the ring stream in the radial direction is possible in a simple manner at the points of the interruption while stabilizing vortices are created between breaks.
• the amount of air in the recirculation-stabilizing partial flow is maximum at the maximum amount of fuel and minimal at the minimum amount of fuel, so that the Air quantity of the recirculation-stabilizing partial flow at maximum fuel quantity and thus the highest gas velocity of the flame also maintains a sufficient recirculation flow for a blue burning of the flame in the combustion chamber.
• the amount of air in the sub-stream close to the fuel jet is constant at all settings of the amount of fuel, so that the sub-stream close to the fuel jet always ensures a basic supply of the fuel jet with air.
• the amount of air in the partial stream near the fuel jet is dimensioned such that the maximum amount of fuel in the partial flow of the recirculation-stabilizing stream is maximum and with a minimum amount of fuel, the combustion air flow is formed only by the partial stream near the fuel jet.
• the amount of air in the partial flow near the fuel jet is approximately in the same order of magnitude as the amount of air of the maximum recirculation-stabilizing partial flow, this being provided in particular for a burner whose burner output can be varied by a factor of five. No details have so far been given regarding the orientation of the recirculation-stabilizing partial flow entering the combustion chamber.
• the recirculation stabilizer could be provided
• the stabilizing effect for the recirculation flows is particularly great when the recirculation-stabilizing partial flow enters the burner chamber in the form of a current pattern lying on a circular cylinder.
• This current pattern could be a cylindrical flow, for example.
• the current pattern is composed of parallel individual streams, so that there is in particular between the individual streams
• the component streams are arranged at a constant angular distance from one another, so that a space remains through each component stream through which the internal recirculation flow can pass through to get to the fuel jet and heat it up by the hot combustion gases carried by the inner recirculation flow, so that a better evaporation of the oil droplets takes place in it.
• the ratio of the angular distance between two component streams to the angular width of the inlet cross section of each component stream is between approximately 10 and approximately 0.1. It is particularly advantageous if the ratio of the angular distance to the angular width of the inlet cross section is between approximately 2 and 0.5, even better 1.5 and 0.7.
• a preferred embodiment provides that
• Ratio is in the range of approximately 1.1.
• an internal recirculation flow which runs back from the blue-burning flame to the non-burning part of the fuel jet, is formed, which is from the recirculation-stabilizing partial flow of the combustion air is stabilized.
• This internal recirculation flow is particularly important in a liquid burner for heating the liquid droplets generated by the nozzle in the non-burning part of the fuel jet, since this internal recirculation flow leads hot combustion gases from the flame back to the non-burning part of the fuel jet and thus contribute to the liquid droplets evaporate to finally reach a blue-burning flame again.
• Fuel jet flows and is thus guided between the inside of the flame tube and the recirculation-stabilizing partial flow.
• the inner recirculation flow is preferably yellow-burning.
• the inner recirculation flow passes through the recirculation-stabilizing partial flow, which is preferably — as already mentioned — formed from individual component jets in order to facilitate passage of the inner recirculation flow through it. No details have so far been given regarding the location of the feed of the partial stream close to the fuel jet into the combustion chamber.
• An advantageous exemplary embodiment provides that the partial stream near the fuel jet flows into the area of a circumference of the nozzle head of the nozzle
• Combustion chamber flows in.
• the cross section required for the partial flow near the fuel jet can be made available by the partial flow near the fuel jet flowing into the combustion chamber through a passage between the nozzle head and an edge of an inflow opening provided for the partial flow near the fuel jet, so that the size of the passage has the flow cross section for the partial stream close to the fuel jet.
• a particularly advantageous intermixing of the partial flow close to the fuel jet and the fuel in the combustion chamber results when the inflow opening is designed to generate turbulence for the partial flow close to the fuel jet.
• the inflow opening is provided with a swirl edge or a swirl cutting edge.
• An advantageous exemplary embodiment provides that the fuel jet forms a cone, in particular a full cone, starting from a simply connected nozzle opening, since this can be produced particularly easily and can also be formed particularly easily homogeneously with a droplet size that is as homogeneous as possible.
• the burner housing comprises a prechamber in which the nozzle is arranged and which is separated from the combustion chamber by a separating element.
• An advantageous exemplary embodiment provides that the combustion chamber extends from a plane which is close to the nozzle opening, that is to say, that the fuel jet advantageously extends immediately after emerging from the nozzle opening in the combustion chamber and not in part before this combustion chamber. This allows, in particular, an advantageous mixing of the inner and optionally outer recirculation flows with the fuel jet in order to achieve a blue-burning flame with optimal combustion values, that is to say in particular optimal NOX and CO content.
• the combustion chamber has an essentially constant cross section between the separating element and the region of the flame root.
• This cross section gives sufficient space for the formation and guidance of the recirculation flows.
• the separating element can be designed in any manner, for example similar to EP 0 430 011. However, it is particularly advantageous if the separating element is an aperture, since this constructive solution is characterized by its simplicity.
• the screen itself could have a curved shape, such as that of DE-OS 40 09 222.
• the screen extends in one plane, since such a shape of the screen is structurally particularly easy to manufacture on the one hand and on the other hand has the advantage that it enables the admixture of the recirculation flows, that is to say both the inner and the outer recirculation flow, in a particularly advantageous manner.
• Combustion conditions especially in a combustion chamber to be free of mechanical flow-guiding elements, which in turn has the particular advantage that on the one hand it allows a power variation in a simple manner, but on the other hand also has fewer problems with undesirable pollutant emissions when starting, i.e. warming up the burner.
• the recirculation space is preferably designed such that it extends at least to the flame root. No details have so far been given with regard to the dimensioning of the recirculation space.
• An advantageous exemplary embodiment provides that the recirculation space has an outer diameter, for example corresponding to the inner diameter of the flame tube, which is approximately 1.5 to approximately 3 times larger than the diameter of the partial circle from which the recirculation-stabilizing partial flow enters the recirculation space.
• the recirculation space has an inner diameter which is approximately 2 to 2.5 times larger than the diameter of the pitch circle.
• Particularly advantageous conditions can be achieved if the recirculation space has a diameter which is of the order of magnitude approximately 2 times as large as the diameter of the pitch circle.
• This flame space can have the same inner diameter as the recirculation space. However, it is particularly advantageous if the flame space has an inner diameter which is at most the same size or smaller than the recirculation space. This solution is especially for small ones Burner capacities, for example less than 20 kW, are advantageous because the flame space narrows to the spatial one
• Stabilization of the flame contributes and thus prevents the flame from swinging back and forth in the flame space.
• a solution that is particularly advantageous in terms of dimensions provides that the outer diameter of the flame space, for example corresponding to the inner diameter of the flame tube at this point, is in the range of approximately 0.6 to 0.9 times the diameter of the recirculation space. It is particularly advantageous if the inner diameter of the flame space is in the range of approximately 0.8 times the inner diameter of the recirculation space.
• An advantageous exemplary embodiment provides that the burner housing is provided with openings through which a cold combustion gas leads
• Recirculation flow enters the combustion chamber.
• This external recirculation flow is known to reduce the proportion of nitrogen oxides, as described for example in DE 40 09 222.
• the solution according to the invention provides for further use of the outer recirculation flow in such a way that the outer recirculation flow is close to the Separating element enters the combustion chamber and is so large that a flame root of the blue-burning flame is at least 1 cm from the nozzle and that a non-burning part of the fuel jet spreads conically with the addition of combustion air between the nozzle and the flame root.
• the external recirculation flow is used not only to reduce the proportion of nitrogen oxides, but in particular also to obtain a sufficiently large non-burning part of the fuel jet in the combustion chamber, which has a sufficient admixture of combustion air and recirculating Allows gases.
• a sufficient admixture of the hot gases of the inner recirculation flow also enables the fuel jet to optimally evaporate the liquid droplets in the fuel jet through the hot gases and thus to ensure a blue-burning flame.
• Another particular embodiment of the solution according to the invention provides that the outer recirculation flow enters the combustion chamber near the separating element and that the latter faces the inner recirculation flow shields the separating element, which is formed as a flow flowing back in the combustion chamber from the blue-burning flame to the non-burning part of the fuel jet.
• the outer recirculation flow is additionally used to keep the inner recirculation flow with the hot gases away from the separating element and thus to prevent excessive cooling of these gases by the cold separating element and rather to prevent these gases in front of the separating element with not being too strong Cooling, namely only by the external recirculation flow to the fuel jet for mixing with the same.
• the outer recirculation flow could in principle enter the combustion chamber in any way.
• the outer recirculation flow enters the combustion chamber separately from the combustion air flow, so that the separate flow guide makes it possible to better position and course the external recirculation flow and, above all, independently of the combustion air, which has a different purpose, namely serves to oxidize the fuel.
• the outer recirculation flow on the one hand, its mass flow can be defined more easily and better, and thus the length of the non-burning part of the fuel jet is also easier to determine.
• the shielding of the inner recirculation flow from the partition can also be achieved much more easily with a separate guidance of the outer recirculation flow.
• the outer recirculation flow enters the combustion chamber directly through recirculation openings in the flame tube, so that the course of the recirculation flow can be advantageously determined by appropriate location, arrangement and size of the recirculation openings.
• a particularly advantageous embodiment provides that a surface area of the openings provided for the entry of the combustion air flow into the combustion chamber corresponds at most approximately to the surface area of the openings provided in the flame tube for the external recirculation flow.
• An advantageous exemplary embodiment provides that the combustion air flow is passed through the prechamber.
• a particularly advantageous embodiment provides that the combustion air flow flows through the separating element into the combustion chamber. It is also advantageous if the combustion air flow flows through the prechamber before it enters the combustion chamber, so that a very compact design of the burner according to the invention is possible.
• An advantageous exemplary embodiment provides that the combustion chamber is enclosed by a flame tube of the burner, so that this flame tube of the burner permits a defined geometrical environment of the combustion chamber and thus in particular a defined configuration of the recirculation flows.
• the flame has a flame root located in the combustion chamber, that is to say the combustion chamber with the flame tube extends at least as far as
• Flame root stretches. It is even more advantageous if the combustion chamber extends beyond the flame root and expediently still surrounds a substantial part of the blue-burning flame.
• this flame tube is preferably provided with openings for forming an external recirculation flow. Furthermore, it is advantageously provided that a flow stabilization element is arranged in the flame tube, which element extends from the diaphragm in the direction of a foot region of the flame to a maximum of approximately a quarter of the distance between the diaphragm and the flame.
• This flow stabilization element has nothing to do with the mixing tube known from the prior art, since the known mixing tube only allows the formation of a single recirculation flow, while the flow stabilization element according to the invention is also designed such that it permits the formation of several recirculation flows, in particular the formation of the the respective amounts of fuel and air required for recirculation flows.
• the flow stabilizing element extends at most over approximately one sixth of the distance between the diaphragm and the foot region of the flame.
• the combustion chamber is designed free of flow stabilization elements for recirculation arranged within it.
• the combustion chamber - as already mentioned at the beginning - is designed without a mixing tube.
• An advantageous exemplary embodiment provides that an adjusting device is provided for adjusting the air quantity of the combustion air flow.
• the adjusting device is preferably designed such that when the amount of air is set, the location of the entry of the combustion air flow into the combustion chamber in the radial direction is essentially invariant to the fuel jet. This has the great advantage that an optimal stabilization of the recirculation with all settings of fuel quantity and combustion air quantity is possible by determining the location of the entry of the combustion air flow.
• the setting device has locally fixed openings for the combustion air flow, which can be adjusted to different cross sections.
• the adjusting device comprises an adjusting element which is rotatably mounted on the diaphragm and by means of which the cross section of an opening provided in the diaphragm can be adjusted.
• the adjusting element is designed as an adjusting disk rotatably mounted on the diaphragm, which can be brought into different rotational positions relative to the diaphragm and to the openings provided in the diaphragm.
• the adjusting element in the form of a closure element, for example one, which varies the cross section of the opening provided in the diaphragm
• Stopper to form, which is movable toward or away from the opening.
• this setting element can be designed in such a way that it can be set in different discrete setting positions.
• the setting element is continuously adjustable, so that the cross sections between a maximum value and a minimum value can thus be varied continuously.
• the adjusting device can be designed such that it can be adjusted manually, for example with an appropriate tool.
• the adjusting device can be set via a controllable actuator.
• the nozzle is a return nozzle.
• Such a return nozzle can be adjusted particularly simply by assigning an adjustable return valve to it, which enables the return of the return nozzle to be variably adjusted and thus also the amount of fuel emitted by the nozzle.
• the return valve is designed in such a way that different amounts of fuel in the fuel jet can be set with it.
• the return valve is continuously adjustable, so that the fuel quantity can be continuously adjusted and adjusted.
• the return valve is adjustable by means of an actuator.
• a particularly advantageous embodiment of the solution according to the invention provides that the burner has a control with which the fuel quantity and the air quantity of the combustion air flow can be adjusted. With such a control, an optimal setting of both the fuel quantity and also achieve the amount of combustion air, especially with regard to stoichiometric or near-stoichiometric combustion.
• controller controls the actuator of the return valve.
• the controller controls the actuator of the setting device.
• control burner outputs can be predetermined.
• control burner outputs can be variably predetermined.
• a particularly advantageous exemplary embodiment provides that the control regulates the amount of fuel and the amount of air in accordance with a predetermined output on the one hand in accordance with this output and on the other hand with regard to stoichiometric or near-stoichiometric combustion.
• an advantageous exemplary embodiment provides that the amount of fuel can be adjusted in that the burner is designed as a kit with different nozzles that can be inserted into the same burner housing. The amount of fuel is adjusted by inserting the appropriate nozzle into the burner.
• the nozzles all have essentially the same spray pattern and in particular a substantially identical outer contour on the air flow side and only deliver different amounts of fuel.
• an advantageous exemplary embodiment regarding the adjustment of the air quantity provides that the air quantity is adjustable in such a way that the burner is designed as a kit with setting parts for the air quantity of the combustion air flow that can be interchangeably inserted into the same burner housing. By providing the different adjustment parts, an adjustment of the combustion air flow is possible.
• At least one partial flow of the combustion air flow can be set for all setting parts.
• a particularly advantageous embodiment provides that the partial flow near the fuel jet is constant in the setting parts, while the recirculation-stabilizing partial flow can be set to different values with different setting parts.
• the kit comprises an identical burner housing for all burner outputs.
• Burner performance includes an identical fan.
• the kit comprises an identical combustion chamber.
• the kit comprises an identical nozzle assembly for all burner outputs.
• FIG. 1 shows a longitudinal section through a first embodiment of a burner according to the invention.
• FIG. 2 shows a partial longitudinal section through a nozzle of the burner according to the invention
• Fig. 3 is an enlarged view of a front area of the
• FIG. 4 shows a section along line IV-IV in FIG. 3; 5 shows a section along line VV in FIG. 1 with the recirculation-stabilizing partial flow at maximum or reduced to zero, with the adjusting disk partially broken away;
• FIG. 6 shows a section as in FIG. 5 with a reduced recirculation-stabilizing partial flow with the adjusting disk partially broken away;
• Fig. 7 is a section as in Fig. 5 with minimal recirculation stabilizing! Partial flow;
• FIG. 8 shows a perspective illustration of the conditions in the combustion chamber with the flame tube partially broken away
• Fig. 9 is an enlarged fragmentary representation of the in
• FIG. 10 shows a section similar to FIG. 1 of a second exemplary embodiment of the burner according to the invention.
• FIG. 11 shows a section similar to FIG. 1 of a third exemplary embodiment of the burner according to the invention
• 12 shows a section similar to FIG. 1 of a fourth exemplary embodiment
• FIG. 13 shows a section similar to FIG. 1 of a fifth exemplary embodiment
• FIG. 14 shows a section similar to FIG. 1 of a sixth exemplary embodiment of the burner according to the invention.
• FIG. 15 shows a section along line XII-XII in FIG. 14 with a maximum recirculation-stabilizing partial flow and the orifice provided for setting the same;
• Fig. 16 shows a section as in Fig. 15 when inserted
• Fig. 17 shows a section as in Fig. 15 when inserted
• a first exemplary embodiment of a burner according to the invention shown in FIG. 1, comprises a burner housing, designated as a whole by 10, with a support tube 12 and a flame tube 14 adjoining this.
• a blower Arranged in the support tube 12 in an end region opposite the flame tube is a blower, designated as a whole, which comprises a blower drive 18 and a blower wheel 20.
• This fan 16 generates an air flow 22 passing through the support tube 12 and flowing in the direction of the flame tube 14.
• a nozzle assembly designated as a whole by 24, which has a nozzle carrier 26 with a nozzle 28 screwed into it.
• the nozzle 28 is detailed below
• the return nozzle described is formed and is supplied with liquid fuel, in particular oil, via a nozzle feed line 30, while part of the fuel supplied in the nozzle feed line 30 flows back again via a nozzle return line 32, throttling the return line via an adjustable return valve 34 arranged in the nozzle return line 32 is possible.
• the fuel is fed into the nozzle feed line 30 via a fuel feed pump 36, which is preferably also driven by the drive 18 of the blower 16, in particular on the same shaft as the blower wheel 20.
• This fuel feed pump 36 is fed with fuel via a pump feed line 38 and is also connected to a return line 40, in which excess fuel flows back from the fuel feed pump 36.
• the nozzle return line 32 after the return valve 34 also opens into this return line 40. 2, 3 and 4, the nozzle 28 comprises a nozzle head 50, which in turn is screwed onto a nozzle body 52 and receives a swirl body 54.
• the nozzle head 50 is in turn also screwed into the nozzle carrier 26 so that the nozzle body 52 lies in a recess 56 of the nozzle carrier 26, the recess 56 forming a fuel supply area 58 which is connected to the nozzle feed line 30 and a return area 60 which is connected to the nozzle return line 32 is connected.
• the fuel entering the fuel supply area 58 preferably flows through a filter 62 and then flows through two opposing inlet channels 64 des
• Nozzle body 52 into further inlet channels 66 in the swirl body 54 and from these, as shown in FIG. 3, into an annular inlet space 68 of the swirl body 54, which is closed by a support plate 70 that closes off the swirl body 54 on the end face.
• the fuel enters into a swirl space 74 located radially inside the annular inlet space 68, in which a swirl flow is formed which corresponds to the orientation of the swirl channels 72, and from this swirl space 72 the fuel passes through an annular circumferential gap 76 into a spray hole 78, from which a
• conical fuel jet 80 emerges.
• a return channel 82 in the swirl body 54 which is the
• Swirl body 54 passes through and merges into a return channel 84 arranged in the nozzle body 52, which then finally opens into the return area 60 of the recess 56, which in turn is in turn connected to the nozzle return line 32.
• the nozzle assembly 24 together with the nozzle 28 is arranged within the support tube 12 in a prechamber 48, which is also penetrated by the air stream 22.
• the prechamber 48 is closed off by a one designated as a whole by 90 and inserted into the support tube 12
• Diaphragm which is located downstream of the nozzle 28, a combustion chamber 92 which is surrounded by the flame tube 14.
• the flame tube 14 is also preferably held on the support tube 12.
• the orifice 90 is arranged such that the spray bore 78 with a nozzle opening is close to or in the plane 89 of the orifice 90 and the fuel jet 80 emerging at the nozzle 28 is essentially completely in the
• Combustion chamber 92 spreads.
• the screen 90 is provided with an inflow opening 94 arranged coaxially to the longitudinal axis 86 of the nozzle 28.
• the inflow opening 94 is also selected to be large enough that between an edge 96 of the inflow opening 94 and an outer side 98 of the nozzle head 50 facing this edge 96 there remains an annular passage 100 through which a partial stream 102 close to the fuel jet, one overall from the antechamber 48, into the combustion chamber 92 incoming combustion air flow passes.
• the edge 96 of the inflow opening 94 is also provided with a vortex edge 104, which leads to the formation of eddies in the partial flow 102 and is formed, for example, by a step-like cross-sectional constriction of the inflow opening 94.
• Another partial flow 106 of the combustion air flow entering the prechamber 48 into the combustion chamber 92 passes through openings 110 arranged radially outside the inflow opening 94 in a circular ring region 108, which are preferably on the partial circle 109 at equal angular intervals and with spaces 111 around the center of the
• Annular region 108 are arranged.
• the openings 110 preferably have an extension in the azimuthal direction with respect to the pitch circle 109 which corresponds to an angle which is approximately one to two times the angle corresponding to the extension of the spaces 111.
• the openings 110 can extend in the azimuthal direction over an angle which corresponds to approximately 0.1 to approximately 8 times the angle of the extension of the spaces 111.
• the openings 110 are arranged in such a way that the partial flow 106 of the combustion air flow enters the combustion chamber 92 through the spaces 111 between the openings 110 in the form of a flow pattern corresponding to a circumferentially interrupted ring flow and thus the formation of an inner recirculation flow 112 and also an outer flow Recirculation flow 119 in the combustion chamber 92 is stabilized so that a flame root 114 of a flame 116 formed in the combustion chamber 92 is at substantially the same distance from the orifice 90, irrespective of a quantity of fuel carried by the fuel jet 80 and a corresponding amount by the partial flows 102 and 106 corresponding amount of combustion air entering the combustion chamber 92.
• the flows according to the invention in the combustion chamber 92, shown in FIG. 8, thus include the partial flow 102 near the fuel jet, which is cylindrical and surrounds the fully cone-shaped fuel jet, and which enters the combustion chamber 92 with a flow direction 103, which runs parallel to a flow direction 79 of the fuel jet 80. Furthermore, the recirculation stabilizing
• Partial flow 106 which has a flow direction 107 parallel to the flow direction 79 in the form of Individual flows 105 enter the combustion chamber 92, the individual flows 105 lying on a circular cylinder which, in cross section, has the shape of the circular ring area on the orifice 90
• the flame root 114 in turn adjoins a non-burning part 81 of the fuel jet 80, which has a length of approximately 1 to approximately 4 cm, preferably approximately 1 to approximately 3 cm, and from this the flame 116 spreads out, which spreads out creates an inner wall region 15 of the flame tube 14 before it leaves it.
• the area of the combustion chamber 92 from the orifice 90 to the inner wall area 15 on which the flame 116 contacts forms a so-called recirculation space 91.
• hot gas flows in the form of an internal recirculation 112 between the flame tube 14 and the partial flow 106 back in the direction to the aperture 90 and in front of the aperture 90 inwards between the individual streams 105 in the direction of the non-burning part 81 of the fuel jet 80 in order to heat the non-burning fuel on the way to the flame root 115 and also the combustion air.
• cold combustion gas exits the respective boiler in the form of the outer one via outer recirculation openings 118 arranged in the flame tube 14 after the orifice 90 Recirculation flow 119 into the recirculation space 91 close to the orifice and substantially prevents contact between the hot gases of the inner recirculation flow 112 and the cold orifice 90.
• the outer recirculation flow 118 also passes close to the screen between the individual flows 105 and then mixes with the combustion air flow 102, 106 in order to increase the mass flow passing through the flame tube 14 to such an extent that the flame root 114 is at a constant distance of at least 2 cm from the screen 90 and thus also from the nozzle 28 remains that the non-burning part 81 of the fuel jet 90 is long enough to evaporate the oil droplets therein almost completely.
• the sum of the areas of the openings provided for the entry of the combustion air flow into the combustion chamber is preferably such that it is at most approximately the sum of the areas of the recirculation openings for the external recirculation, in particular that Sum of the areas of the outer recirculation openings 118, which are designed as elongated slots in the circumferential direction, corresponds to.
• 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 approximately 19.2, preferably between approximately 0.9 and 5.1.
• the flame chamber 117 then adjoins the recirculation chamber 91.
• the partial flow 102 near the fuel jet is preferably designed such that it stabilizes the corresponding recirculation flow without the recirculation-stabilizing partial flow 106 at the lowest burner output (FIG. 9 lower half) and then the recirculation-stabilizing partial flow in the case of large burner outputs 106 takes over the stabilization (FIG. 9 upper half) which the partial stream 102 near the fuel jet can no longer perform.
• the burner is dimensioned differently, it is also possible to provide both the partial flow 102 close to the fuel jet and a minimum partial flow 106 which stabilizes recirculation at the lowest power.
• Such stabilization of the recirculation flows 112 and 119 can be achieved in particular if an outer diameter of the recirculation space 91 of the combustion chamber 92 corresponding to the inner diameter of the flame tube is approximately 1.5 to approximately 3.9 times, better still approximately two to three times that Diameter of a partial circle 109 of the annular region 108, it is even more advantageous if the outer diameter of the recirculation space 91 of the combustion chamber 92 is approximately 2.2 to approximately 2.6 times, preferably approximately 2.2 to approximately 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 approximately 1.0 and approximately 4.2, preferably between approximately 1.82 and approximately 2.0.
• the central inflow opening 94 is dimensioned such that an outer diameter of the recirculation space 91 (corresponds to the inner diameter of the flame tube 14) of the combustion chamber 92 is approximately 3.4 to approximately 8.5 times, more preferably approximately 4 to about 6 times, more preferably about 4.4 to about 5.9 times the diameter of the central inflow opening 94.
• an adjusting device designated as a whole by 120, which, as shown in FIGS. 5 to 7, comprises an annular adjusting disc 122 which has openings 124 identical to the openings 110, which also in FIG the same angular distances as the openings 110 and at the same radial distance from a center of the annular region 108.
• the annular adjusting disk 122 lies, as shown enlarged in FIG.
• a cylindrical disk-shaped depression 126 provided in the diaphragm 90, which is open to the antechamber 48.
• the rotatable guidance of the adjusting disc is carried out by mounting the same with its outer edge 128 on a cylindrical edge 130 of the depression 126.
• the shim 122 is adjustable so that, as shown in FIGS. 5 to 7, either the openings 124 are congruent with the openings 110, so that the maximum cross section for the partial flow 106 replacing the individual openings 110 is available, or so rotatable that the openings 124 are no longer congruent with the openings 110 and only the overlapping regions of the openings 110 and 124 allow the partial flow 106 to pass, so that the air volume of the partial flow 106 is reduced, as shown in FIG. 6.
• the partial flow 106 can be completely interrupted, namely when the openings 124 are at a gap between the openings 110.
• the adjusting disk 122 To twist the adjusting disk 122, it is provided in a partial area of its outer edge with a toothing 132, into which a toothing 134 of an adjusting pinion of the adjusting device 120, denoted as a whole by 136, engages.
• This adjusting pinion is in turn rotatably mounted on the diaphragm 90, and in the simplest case is mounted in a further cylindrical bearing recess 138 in the diaphragm 90, the rotatable bearing being effected by the toothing 134 resting on cylindrical wall surfaces 140 of the bearing recess 138.
• Both the adjusting disk 122 and the adjusting pinion 136 are held in their respective recesses 126 and 138 by fixing elements (not shown in FIG. 9), so that they each abut the recesses on the bottom side.
• the setting pinion 136 is, for example, self-lockingly mounted in the bearing recess 138 and is provided, for example, with a slot 142, which makes it possible to turn the setting pinion 136 using a conventional screwdriver, so that setting the setting disks 122 is also possible, the respective settings of the shims 122 are maintained by the self-locking adjustment pinion 136.
• the first embodiment now works such that when the partial flow 106 is interrupted, only the combustion air flowing from the partial flow 102 through the passage 100 into the combustion chamber 92 is available as combustion air quantity.
• the amount of fuel emitted from the nozzle 28 into the fuel jet 80 is adjusted in accordance with this amount of air, the amount of fuel being adjusted so that the flame 116 burns blue and stoichiometric or near-stoichiometric combustion occurs.
• This adjustment of the fuel quantity takes place via the adjustment of the return valve 34 and thus via the fuel flow returning from the nozzle 28 via the nozzle return line 32 into the return line 40.
• the partial flow 106 can also contribute to the partial flow 102 of the combustion air flow near the fuel jet, this partial flow 106 additionally stabilizing the recirculation flow 112 at higher burner outputs.
• the maximum amount of combustion air in the partial flow 106 approximately 2 times the cross-sectional area is available for the entry of the combustion air flow from the pre-chamber 48 into the combustion chamber 92 than with a completely prevented partial flow 106.
• the amount of fuel discharged from the nozzle 28 into the fuel jet 80 is adjusted by the aforementioned setting of the return valve 34 with a corresponding throttling of the fuel returning from the nozzle 28.
• a distance between the flame root 114 of the flame 116 and the diaphragm 90 is essentially constant, and a blue burning of the flame 116 with essentially stoichiometric or near-stoichiometric combustion can be set for all power settings of the burner.
• a flow guide ring 150 is provided in the second exemplary embodiment, which is arranged at a distance from the orifice 90, and with its front edge 152 up to a maximum of up to a quarter a distance between the aperture 90 and the foot portion 114 of the flame 116 extends. Furthermore, the flow guide ring 150 is arranged with a rear edge 154 facing the orifice 90 at a distance from the orifice 90, so that the recirculation flow 112 can enter the flow guide ring 150 from the side of the orifice 90 between the edge 154 and a front side 156 of the orifice 90 .
• the flow ring 150 also serves an additional purpose Stabilization of the recirculation flow 112, a significant distance between the front edge 152 and the foot region 114 of the flame 116 being necessary in order to ensure the formation of a strong recirculation flow 112 at different power settings of the burner according to the invention and to support the effect of the recirculation-stabilizing partial flow 106.
• the flow guide ring 150 is preferably held on the orifice 90 with webs 158.
• a third exemplary embodiment of a burner according to the invention shown in FIG. 11, those parts which are identical to the first exemplary embodiment are provided with the same reference numerals, so that with regard to the description of these parts, reference is also made in full to the design of the first exemplary embodiment can be.
• an actuator 160 is provided for the setting of the return valve 34 and an actuator 162 for the setting of the setting pinion 136, both of which can be controlled via a common controller 164.
• Power settings of the burner according to the invention are built into this control 164 via an input 166, the control 164 being based on each power setting Input 166 makes the corresponding setting of the return valve 34 and the actuator 162 of the adjusting device 120. For example, this is through in one
• a lambda probe 168 is additionally arranged in the exhaust gas flow of the flame 116, which is also connected to the controller 164, so that the controller 164 uses rough settings to adjust the power the actuators 160 and 162 are additionally able to fine-tune either the amount of combustion air or the amount of fuel in order to maintain stoichiometric or near-stoichiometric combustion conditions.
• control 164 is constructed in such a way that the desired outputs of the burner according to the invention can be set by means of a setting transmitter, for example manually.
• control 164 is designed such that, via an overall control of a system, for example a heating system, in which the burner according to the invention is integrated, a specification is made for the required output of the burner according to the invention, so that the Controller 164 then adjusts the actuators 160 and 162 accordingly depending on the requested output of the burner according to the invention and carries out a fine adjustment on the basis of the measured values of the lambda probe 168.
• the flame tube 14 is narrowed radially over its length in the region of the flame chamber 117 following the recirculation chamber 91 up to the front end 170, so that the inner wall region 15 against which the flame 116 rests is already radially offset inwards.
• This flame tube allows it especially for small ones
• Burner outputs preferably less than 20 kW, to obtain a flame 116 which is stable in the flame tube 14. Furthermore, this geometry prevents undesired drawing in of smoke gases from the front end of the flame tube 14.
• the openings 110 are closed by means of conical plugs 172 which are held on rods 174 and are movable in the axial direction of the support tube 12 via a guide 176 on
• Nozzle assembly 24 are guided in the support tube 12. Depending on how far the conical plugs 172 into the openings 110
• each opening 110 protrude, a reduction in the cross-sectional area of each opening 110 is possible.
• FIG. 14 In a sixth exemplary embodiment of a burner according to the invention, shown in FIG. 14, those parts which are identical to those of the first exemplary embodiment are provided with the same reference numerals, so that reference is also made in full to the statements relating to the first exemplary embodiment with regard to these parts can.
• a power setting is also possible in the sixth exemplary embodiment, shown in FIGS. 14 to 17, but in this exemplary embodiment the burner according to the invention is constructed in the form of a kit.
• a nozzle 28 designed as a return nozzle with a nozzle return line 32 and a return valve 34 provided therein for adjusting the fuel flow
• a set of several nozzles 228 are provided, each of which has the same spray pattern and the same air flow-side outer contour and thus the same shape of the fuel jet 80, however at deliver different amounts of fuel.
• the fuel is supplied via the fuel feed pump 36 and the nozzle feed line 30, but a nozzle return line 32 is unnecessary.
• the different nozzles 228 correspond to different outputs of the burner according to the invention.
• the orifices 290a to c differ in the cross section of the openings 210 provided for the partial flow 106, but not with regard to their position, the openings 210a being identical to the openings 110 with regard to the overall cross section of the openings, while the openings 210b show a total cross section which corresponds to an intermediate setting, for example shown in FIG. 6, and thus also to an intermediate output of the corresponding nozzle 228.
• the openings 210 are entirely absent, so that this corresponds to the position shown in FIG.
• Setting device 120 corresponds to ,, in which the partial flow 106 is completely prevented and the combustion air flow is formed only by the partial flow 102.
• one of the orifices 290a to 290c is to be installed in the support tube 12, the orifices 190 being removably held in the support tube in the fourth exemplary embodiment.
• a tripod 294 is held on the nozzle assembly 24 by means of a retaining ring 292, which acts on the respective panel 290 on its side 296 facing the prechamber 48 and presses it against a sealing ring 298 in the direction of the flame tube 14.
• the nozzle assembly 26 as a whole is displaceable in the direction of a longitudinal axis 300 of the support tube 12 and is acted upon by a spring (not shown in FIG. 14) in the direction of the flame tube 12. It is thus possible to remove the orifice 290 in the direction of the prechamber 48, while the orifice 290 in the direction of the flame tube 14 through the seal ring 298, for example
• combustion chamber 92 is designed, in the same way as is preferably shown in connection with the first exemplary embodiment, free of mechanical flow guidance 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, is accordingly available for the partial stream 106 provided cross sections of the openings 210 ensures a function corresponding to the first embodiment.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Pre-Mixing And Non-Premixing Gas Burner (AREA)

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• 1994
  • 1994-12-17 AT AT95905078T patent/ATE199452T1/de not_active IP Right Cessation
  • 1994-12-17 WO PCT/EP1994/004205 patent/WO1995016883A1/fr active IP Right Grant
  • 1994-12-17 EP EP95905078A patent/EP0683884B1/fr not_active Expired - Lifetime

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