EP2002178B1 - Burner system, in particular for ovens fired by biosolids and method for operating such a burner system - Google Patents

Abstract

The system has an air inlet provided on a blower, which lies with a delivery device in a blower area. A transfer area (30) lies between the blower area and a firing area (32). A shield wall is provided between the blower area and the transfer area, which blows with an open connection for the blower area with an air turbulence. An air supply on the firing area is assumed by the transfer area, where the air supply is designed as openings in the form of single drillings or as an annular gap, and a fire tube is provided with two sections that are set against each other.

Description

The invention relates to a burner system, in particular for bio-solids-fired oven, according to the preamble of claim 1, and a method for operating such a burner system.

A burner system of the aforementioned type is known from WO 90/14558 known. In this, the burner trough delimits the fan chamber against the gas mixing chamber located in the transition to the fuel gas outlet, and only an annular gap-like connection is provided between the fan chamber and the gas mixing chamber, which is bounded radially inwardly by the outer circumference of the burner trough and radially outwardly by the inner circumference of the housing , The air supplied to the gas mixing chamber via the fan device thus flows over the burner trough on the circumference, so that no outflow of the burner trough emanating from the fan chamber is provided in the direction of the gas mixing chamber. Rather, the combustion material located in the burner trough is acted upon only by the proportion of air, which flows at the outgoing from the fan, cyclone-like and directed against the fuel gas flow through the gas mixing chamber as a result of the central vacuum in the direction of the burner trough and in the burner trough back to the Fuel gas outlet is deflected. Accordingly, only a partial combustion takes place in the burner trough open only to the gas mixing chamber and in the gas mixing chamber itself, and further burnout in the region of the fuel gas outlet and afterwards, whereby the combustion conditions are difficult to influence, since they also depend on the respective power of the blower device change.

From the EP 0 076 353 is a burner system known for biomass. This has a degassing chamber, which in turn is enclosed by a chamber housing insulating. The chamber housing is in turn in an insulating burner housing on the bottom and defines against the burner housing circumference and the ceiling side an enclosing ventilation chamber. In the degassing chamber is located at one end face then a fuel bowl, the biomass is applied to a via the front side passing through conveyor. The fuel cup defines via its drawn down against the bottom of the degassing chamber and adjoining these edges from a ventilation space, which communicates with the degassing chamber via provided in the edges of the burner cup ventilation openings.

The chamber housing the degassing chamber and the burner housing are penetrated by successively and in the ventilation chamber at a distance adjoining, channel sections, of which the burner housing passing through channel section opens as a flame channel on a flame chamber.

On the ventilation chamber, the fresh air is supplied via a blower and starting from the ventilation chamber via regulating elements, the air supply to the ventilation space and the flame channel, which from the degassing chamber Fuel gases are supplied and in which the mixing of the fuel gases with the optionally preheated fresh air for the ignition of the fuel gases and their subsequent combustion takes place in the flame chamber.

From the GB 2 083 184 A a biomass fueled burner system is known in which on a drive unit with fan and conveyor building a burner housing is provided which, merging into each other, receives an upper and a lower burner chamber. From the burner chambers, the lower funnel-shaped tapers against the drive unit, then passes through a transitional space to the upper burner chamber and, starting from the transitional space, enters a funnel-shaped combustion chamber. The perforated peripheral wall of the lower burner chamber forms the inner peripheral wall of the Feuerungsraumes, also perforated outer wall, the inner boundary wall of a communicating with the arranged in the drive unit fan ventilation space having radially outward an annular channel connection to the transition space. At the transitional space, which is open against firebox, a disposal system for combustion residues is connected and via the transitional space is also the fresh air supply to the upper burner chamber, in which the further combustion of the firing chamber has passed to the lower burner chamber combustion gases. The upper burner chamber is enclosed within the burner housing by an annular channel and communicates with this in its upper region via in the inner wall of the annular channel, which simultaneously forms the chamber wall, provided air passage openings in connection, in turn, has a valve-controlled fresh air connection for controlling the temperature of the passed, burned fuel gases and from which the hot fuel gases are exhausted for further use via a suction fan arranged on a fuel gas outlet.

Next is from the EP 1 122 495 A1 a combustor system fueled with biosolids with a burner unit in which a gas mixing chamber associated with the burner unit is located between a blower device of the burner unit and an oven-side firing space, which is radially constricted onto the firing space in coaxial arrangement with the blower device and forms a swirl nozzle. Against the fan chamber of the fan device, the gas mixing chamber is delimited by a screen acting as a thermal barrier screen with this associated supply air distribution head. Fresh air or purified fuel gas is used as supply air as Rezigas.

The blower device works, as well as in the WO 90/14558 , with a conveyor member designed as a link head. The fan room is in the peripheral region of the conveyor member with the gas mixing chamber in open flow communication, so that the supply air via a Zuluft distributor head and / or on the conveyor member axially expiring further supply air supplied supply air from the conveyor member with swirl as the axis of rotation of the conveyor member spiral or helical air vortex the gas mixing chamber is conveyed in and flows in the mixing chamber on the acting as a swirl nozzle crossing cross-section to Feuerungsraum. In furnace-side firing space, this results, after passing through the swirl nozzle, a spiral-shaped gas cylinder, which then widens outward to the crossover cross section and thereby becomes a cyclonic air vortex. As a result of the strong rotation, a vacuum zone is formed centrally, on the basis of which a central backflow vortex results for the gas cylinder ending above the bed of the firing space. This Rückströmwirbel abuts the screen wall, widening and is deflected along the screen wall in the direction of the near-wall, the gas mixing chamber by flowing air swirls and thus re-integrated into this.

Since the in the suction against the screen wall rotating back flowing fuel gas was heated in the furnace, resulting from the admixture to the blower via the fan in the supply vorgeförderten supply air heating the same, and in conjunction with an increase in the air rotation, the CO content in on the screen In the wake flowing back fuel gas vortex reacts with the oxygen of the supply air and results in a given combustion process with internal NO _x reduction due to the given temperatures.

The essentially successive construction of fan chamber, gas mixing chamber and furnace combustion chamber with overflow of the bed of Feuerungsraumes basically allows in particular in connection with the cyclonic air movement long residence times for the fuel gases before they pass from the firebox in the subsequent fuel gas outlet, but requires appropriate Structural provisions with regard to the transition from the combustion chamber to the fuel gas outlet as well as, due to the sequential arrangement of the blower device to the firebox, a corresponding space requirement.

Furthermore, from the EP 0 945 676 A2 a burner for solid fuels, known as wood pellets, in an airtight except for the fuel gas outlet formed combustion chamber is arranged, which is under negative pressure by a downstream aspirator in all operating conditions.

The burner is designed as a burner pot, which has to supply with primary and secondary air at different levels lying radial or radial and bottom-side air supply lines. The circumferentially provided to the burner pot axially spaced air supply channels form secondary air supplies and are connected to a resulting by doubling the pot wall annulus, which in turn is connected to a secondary air supply line.

From the DE 43 44 760 A1 is a furnace for solid fuels, in particular wood chips known, from the combustion chamber via an exhaust fan, the flue gases are sucked off and in the combustion chamber, a combustion bowl is arranged dipping into an air supply space. The fuel bowl has bottom and peripheral intake ports for primary air. Furthermore, secondary air is supplied above the edge of the combustion dish, with the primary and the secondary air intake running partly through common air channels.

The invention has for its object to further improve such a burner system in terms of efficiency and the reduction of polluting pollutants.

According to the invention, this is achieved with the features of claim 1, according to which the Brennungsraum delimiting burner trough is immersed in the transitional space and a storage space delimiting, so that the burner system can be represented as a very compact unit, with respect to the place of use as well the feed of the fuel and access to the burner trough is advantageously designed. In addition, the offers in the Transitional space dipping and to a storage space delimiting arrangement of the burner trough particularly favorable ways for air supply to the burner trough and the firebox from the point of view of the local air distribution as well as the air movement, tapering on the hearth with burner trough as a helical gas cylinder, and in the firebox and expiring from the firebox as Cyclonic air vortex, which leads due to the centrally generated negative pressure to a return of part of the already exited from the combustion chamber, CO-containing fuel gases into the firing space and thus to an internal NO _x reduction. This is achieved in a very compact design, which is also simple and variable with respect to the basic elements used, so that with the same basic structure also favorable opportunities for variations and variants, even under performance considerations, which in view of a widespread use also already existing wood ovens offer advantages.

In particular, the burner system according to the invention is to be fired with biosolids in the form of pellets, namely wood pellets, which can be dosed at a diameter between 6 and 10 mm in a favorable manner and which have no or only a very small proportion of bark, so that During incineration a small amount of ash results and the resulting dust particles are largely discharged with the fuel gas. A in the furnace supplied fuel gas existing dusty ash content is - when burning in the corresponding purity of existing bio-solids, including bark-free wood in pellet form - for wood ovens because of the mineral content of the ash but quite desirable.

With regard to the influence of the air currents and the air distribution, it proves appropriate, the To carry out air supply from the storage space to the burner trough as partial air supply, so that in a simple manner specifically related influence options arise.

As partial air supply systems, in particular those are provided which connect the storage space of the transitional space as the first partial air supply to the burner trough in the region of the floor and as a second partial air supply the storage space of the transitional space with the burner trough in adjacent wall region and the third partial air supply from the transitional space to the burner trough depart in the peripheral region remote from the bottom, wherein these partial air feeds can be made variable with respect to the respectively supplied amount of air, so that - also depending on pressure - result in influencing possibilities both with regard to the respective amount of air, the respective flow intensity as well as the respective flow direction. These are also with regard to the optimization of the respective system and the experimental work to optimize such a system advantage.

In particular, the first and the second partial air feeds preferably comprise openings in the wall of the burner trough, which are designed as bores or slots, wherein the arrangement as well as the configuration preferably takes place in each case to the effect that corresponding air guide effects result. This example, characterized in that the openings are designed as against the storage space against the direction of flow widening trapping and / or that the openings are designed against the interior of the burner trough as in the direction of the desired air outflows extending air ducts. Such air ducts, for example, by extending against the interior of the burner trough forms, be formed by attached guide body or guide plates. The interior of the burner trough associated air ducts in the form of characteristics, or of guide plates or the like can be used in the invention with advantage also to prevent immediate occupancy of the respective openings in the burner trough with fuel or even deposited with fuel particles or ash.

In principle, the third partial air feeds can also be designed in the manner described. However, it is particularly simple and advantageous to design these third partial air feeds on the output side to form the cup-shaped burner trough in the manner of an annular gap, in particular to form an annular gap.

Preferably, the partial air feeds are at least partially associated with each other delimited space parts of the transition space, which have separate connections to the fan room, which can be extended options for the desired air volume distribution to the individual partial air supplies with respect to the desired speed as well as the respective desired air pressure can be achieved.

A preferred embodiment provides for this purpose, that the first and the second partial air supplies emanate from an inner space part of the transition space as a storage space, which has a separate connection to the fan room. Preferably, the fan room is delimited against the transitional space via a screen wall which extends transversely to the axis of rotation of the conveying member of the fan means and the radially inwardly bounds an annular gap as a connection between the fan room and the storage space of the transition space. The outer boundary of this designed as an annular gap connection is preferably formed by an annular wall, the Transition space to combustion chamber and fan room divided into an inner and an outer part of the room, these space parts extend annularly surrounding the axis of rotation of the conveyor member and wherein the outer space part is designed as an annular air duct, which is in communication with the third partial air supply, preferably summarized by an annular gap can be formed at the level of the edge of the burner trough.

The storage space as part of the inner space part is preferably closed axially via a transverse connection between the burner trough and the inner space part against the outer space part delimiting annular wall, wherein the cross connection is formed for example as a support flange, via which the cup-shaped burner trough is supported on the annular wall. The inner space formed as an annular space part is thus open only to the fan room, so that it proves - even in consideration of the pressure built up on the conveyor member - as storage space for the amount of air on the part of the conveyor member of the fan as a ring roller rotating over the gap connection between screen wall and annular wall is supplied. According to the impressed, resulting from the direction of rotation of the vortex flow openings in the wall of the burner trough results in the burner trough a rotating air movement. In particular, the first, bottom-side partial air feeds also have an air admission of the fuel material located in the burner trough from below, so that a uniform burn-out results, when seen in total around the axis of rotation of the conveyor member spiraling rising gas cylinder.

The radially preferred by the up to the bottom of the fan chamber continuous annular wall between the inner and outer space part the blower compartment delimited by the transition space has a connection to the outer space part, which is preferably formed by a plurality of circumferentially provided for blower chamber recesses in the annular wall, so that the coordination of the respective cross sections of the compounds to the room parts and the distribution of air can be achieved on the space parts, wherein by the radial transfer to the outer annulus in the outer annulus, the air as a helical ring roller upwards, ie in the direction of the third partial air supply moves and the roller-shaped movement of the air flowing to the third partial air supply air Inflowing to the firing chamber amplifies the spiral movement of the air vortex already built up in the cup-shaped burner trough.

The, in the embodiment of the invention, the third partial air supply preferably forming annular gap connection to the outer space part is created in particular by overlapping the combustion space of the gas mixing chamber of a gas mixing head is provided, wherein the crossover cross section from the firing chamber on the gas mixing chamber preferably in or adjacent to the parting plane of the housing Burner system is located, whose upper part is formed by the gas mixing head and the lower part of the blower chamber with the overlying cup-shaped burner trough within the transition space, which is limited to the outside - as a housing wall - by the outer wall of the outer space part of the transition space.

The connection between the upper housing part and the lower housing part, which are preferably designed in sheet metal design, is advantageously carried out by flanging, wherein the flanges can be used simultaneously within the scope of the invention to radially inwardly over the outer space part To form air baffles through which the rising in the outer part of the room air roller can be at least partially diverted to the third partial air supply lines forming annular gap.

Preferably, in the context of the invention, a radial constriction in the transition between the cup-shaped burner trough and the gas mixing chamber given this radial constriction can be created both by the design of the cup-shaped burner trough, as well as in that the inlet cross-section to the gas mixing chamber on the part of the gas mixing chamber with respect to the Diameter of the cup-shaped burner trough is made smaller. Also by this measure, an intensification of the cylindrical air movement ascending from the cup-shaped burner trough into the gas mixing chamber can be achieved, so that cyclone-like effects result, which can lead to a backflow of already passed into the gas mixing chamber fuel gases in the center of the cup-shaped burner trough.

In the region of the bottom of the burner trough, the backflowing gases are redirected while maintaining the rotational movement radially outward, whereby the desired, intensified by the turbulence and low-emission combustion can be achieved over a wide power range of the burner system.

In a further embodiment of the invention, it proves to be expedient if a further Zuluftzuführung, in particular a fresh air supply is provided auslaufend on the fuel gas outlet, which follows via fourth partial air supply to the flame tube, starting from the fan room. For this purpose, the outer space part of the transitional space, via which the third partial air feeds are fed, is preferably used as the connection to the blower chamber, with the fourth, into the flame tube einmündenden partial air feeds can be formed as openings in the form of individual holes or as an annular gap, in the simplest way, characterized in that the flame tube has two successive and mutually offset in diameter sections that leave a corresponding air inlet gap as an annular gap. Thus, an intensive mixing of fuel gases and supply air can be achieved within the flame tube again, which has an advantageous effect on the reduction of the pollutant content of the fuel gases, so that the combustion gases exiting through the flame tube are extremely low in pollutants, at least virtually free of pollutants. Preferably, the flame tube is connected transversely to the axis of rotation extending to the gas mixing chamber, thus extending transversely to the built-up via the fan vortex.

The upper part of the housing which surrounds the gas mixing head is preferably at least partially double-shelled, so that at least in partial areas a channel-like guide adjoining the outer space part of the transitional space results for the part of the supply air which is to be supplied to the fourth partial air supply lines, where appropriate, the corresponding crossover cross sections can also be made adjustable, so that the air distribution can be changed to the individual partial air supply also to existing systems, if desired.

The blower device, which is used in conjunction with the burner system according to the invention, preferably comprises a conveyor member with circumferentially extending in extension of the conveying elements of the conveyor member provided vortex bodies, wherein as a conveying element preferably an impeller is provided in a radial extension to the blades of the vertebral bodies are attached.

The blades of the impeller are preferably curved in the direction of rotation flat, so designed flat convexly curved with respect to the direction of rotation and as a vertebral body expediently in the radial extension of the blades, possibly employed at an angle to the blade plane angled, there are extensions that may be formed closed or structured, so For example, as self-contained chain links or horseshoe-shaped or forked with freely expiring arms. Depending on whether a higher pressure or a larger volume is required for the performance-dependent air flow, the blades are suitably chosen in their curvature - stronger curvature / higher pressure, flatter curvature / higher volume -, in addition to the distribution of the generated rotating air flow is influenced on the space parts of the transitional space or the associated with this partial air supply via the vertebral bodies, the corresponding Abdrängeffekte in the direction of the respective connection to the respective space part of the transition space result.

In the context of the invention is preferably the blower device associated drive, in particular designed as an electric motor, coaxial with the axis of rotation of the conveyor member, and it is further set the drive motor against the bottom of the fan chamber, wherein in the bottom of the fan chamber preferably enclosing the hub of the Conveying member, the air intake takes place, which may include a supply of recirculated fuel gas, in particular according cooled.

For the burner system according to the invention, in particular, an arrangement with an upright extension of the burner part, in particular with a vertical extent in FIG Direction of the axis of the conveyor member as appropriate, which allows in a favorable manner, the supply of the particular formed by wood particles in the form of pellets fuel from the top of the burner trough in. Here, over the circumference of the burner trough several, in particular two approximately diametrically opposite feeds are provided in order to achieve a uniform distribution of the fuel in the burner trough.

Furthermore, an arrangement of an access opening to the firebox in the region of the gas mixing head, that is from above, is expediently provided, wherein the access opening is expediently provided centrally opposite the burner trough so that the extraction of residues, in particular ash residues, from the burner trough is also possible.

For a burner system according to the invention, a distribution of the air quantity conveyed via the blower device proves to be expedient, in which approximately 30% of the fresh or supply air supplied is accounted for by the first and the second partial air feeds, preferably with approximately the same distribution to these partial air feeds. For the third partial air supply proves a share between about 30 and 50% of the fresh air or supply air as appropriate, with a mean value of about 40% is a preferred value. Deviations from this, in particular depending on the quality and / or the consistency of the fuel and the humidity are within the scope of the invention. With reference to the fourth partial air feeds, with regard to the influencing of the pollutant emissions, a proportion of approximately 20 to 30% proves to be expedient, whereby this proportion can be increased, in particular, if cooling of the fuel gases is aimed at via the fourth partial air feeds.

Related to a burner system with a designed as an upright housing enclosed assembly burner part with a fuel gas outlet, with an open against the fuel gas outlet burner trough a Feuerungsraumes and with a burner trough lying between this and the fuel gas outlet gas mixing chamber, and with a lying below the burner part fan with against the burner trough delimited blower chamber and a conveyor member with an upright axis of rotation, on the basis of the fan room, the air supply to the burner part in a rotating air vortex, it is further useful for its compact and lightweight, well insulated construction, when enclosing the burner part and overlapping the gas mixing chamber, So over the circumference and head of the housing this is formed with a double-shell sheath, which is provided as an air duct with opening out on the burner part ports. In particular, the air duct formed by the double-shell casing may be associated with the third and fourth partial air duct, preferably with radial connection to the fan chamber.

Particularly useful is such a configuration, apart from the thermal insulation, and for the noise insulation, both with respect to the fan room as well as the burner part, which has the storage space in the transition between the fan room and burner trough, its radially, inner and axially upper limit by the immersed in the transition space arranged burner trough is formed.

Fig. 1

eine schematisierte Schnittdarstellung eines Brennersystems gemäß der Erfindung,

Fig. 2

wiederum schematisiert, eine Schnittdarstellung des als Förderelement vorgesehenen Gebläserades der Gebläseeinrichtung,

Fig. 3

eine Draufsicht auf das Gebläserad gemäß Fig. 2, und

Fig. 4

eine isolierte Schnittdarstellung eines der im Gebläserad umfangsseitig in Verlängerung einer Gebläseradschaufel vorgesehenen Wirbelkörpers im Schnitt, wobei als Wirbelkörper hier beispielsweise ein Kettenglied vorgesehen ist.

Further details and features of the invention will become apparent from the claims. Furthermore, the invention will be explained below with reference to an embodiment. Show it:

Fig. 1

a schematic sectional view of a burner system according to the invention,

Fig. 2

again schematized, a sectional view of the blower device provided as a conveying element of the blower device,

Fig. 3

a plan view of the impeller according to Fig. 2 , and

Fig. 4

an isolated sectional view of one in the impeller circumferentially provided in the extension of an impeller blade vertebral body in section, being provided here as a vertebral body, for example, a chain link.

The burner system according to the invention comprises, as in Fig. 1 illustrated, designed in particular as a structural unit 1 burner, which is stationary or movable and which, in particular serving a preferred purpose of the invention, is to be used for heating ovens as consumers, being used as fuel bio-solids, especially in the form of wood pellets ,

The illustrated as a unit 1 burner comprises in the embodiment shown, a top part 2 and a lower part 3, the housing parts 4 and 5 in a flange 6, as indicated by the screw 7, are braced against each other. Based on the structure of the assembly 1, the lower part 3 comprises a blower device 8, which is assigned as a drive designed in particular as an electric motor motor 9, with which the conveyor member 10 is drivingly connected via a shaft connection 11. The conveyor member 10 comprises as a conveying element 12, an impeller 13 with blades 14 which extend substantially radially and together with an upper cover plate 15 and a lower channel wall 16 define substantially radially extending channels, which radiate radially inward, substantially in the foot region of the blades 14, from a central suction 17. The suction chamber 17 is closed at the top via the cover plate 15, via which the impeller 13 is also flanged with the shaft connection 11. To the suction chamber 17 corresponds to a central cutout 18, which is bounded by the lower channel wall 16 and the axial, that is in the direction of the axis of rotation 19 of the fan 8, in overlap to an open to the environment suction port 20. The suction opening 20 is, preferably enclosing the central shaft connection 11, provided in the bottom of the outer wall 21 of the housing lower part 5, to which the motor 9 is arranged axially offset. This results in an annular gap between the shaft-side end plate of the motor 9 and the outer wall 21 and it can be used at the same time for cooling the motor 9, the air sucked through the fan 8.

Radially outward to the impeller 13, preferably radially outwardly in extension of the blades 14 projecting, vertebral bodies 22 are provided, which are shown in the embodiment as chain links 23 whose member plane is directed radially to the axis of rotation 19, wherein preferably the respective chain links 23 in extension of the blades 14 are arranged and held by connection to the cover plate 15 and / or the channel wall 16.

The thus designed conveyor member 10 is located in a fan chamber 24 which is bounded below by the bottom of the outer wall 21 of the housing base 5 and the circumferential direction of an annular wall 25 which is enclosed by an inner wall 25 of the housing base 5. The upper boundary of the fan chamber 24 is formed by a screen wall 26, the is fixed to the lower housing part 5, for example by screwing 27 forming as a support pin and ends circumferentially to the inner wall 25 with a radial distance, so that between the shield wall 26 and the inner wall 25, an annular gap 28 as discharge opening 60 results.

Surrounded by the inner wall 25 and spaced from this and also to the screen wall 26, in the exemplary embodiment central and coaxial with the inner wall 25, a combustion chamber 32 which is bounded against the fan room by a cup-shaped or pot-shaped burner trough 33, which has a peripheral wall 34 and has a bottom 35. Supported and fixed in position to the lower housing part 5, the burner trough 33 via a flange 36 with the peripheral wall 34 of the burner trough 33 and the inner wall 25 position-fixed flange.

The annular gap 28 is open axially to the inner space part 29 of a transition space 30, which enclosing the inner wall 25 has an outer space part 31, which is bounded on the outside by the peripheral part of the housing outer wall 21.

Through the burner trough 33 is delimited within the inner space part 28 against the fan chamber 24 to a storage space 61, on which the annular gap 28 formed by the discharge opening 60 from the fan chamber 24 to the inner space part 29 and from which the burner trough 33 on the circumference and bottom side in its peripheral wall 34 and provided in its bottom 35 openings 57 and 58 is supplied.

The outer space part 31 of the transitional space 30, the fan chamber 24 has peripheral openings 37, which constitute as provided in the inner wall 25 recesses, so that the fan room 24 to outer room part 31 and inner space part 29 separate connections in the form of the annular gap 28 and the openings 37 are made. The outer space part 31 extends as an annular channel up to the height of the flange 6, in which the housing parts 4 and 5 adjoin one another, wherein the upper housing part 4 receives a gas mixing head 38 with a gas mixing chamber 39, which is in axial overlap to the burner trough 33, wherein in the flange plane 6 between the gas mixing head 38 and the burner trough 33 by corresponding axial spacing a radially extending annular gap 40 remains over which the outer space part 31 is transverse to the extension direction of the rotation axis 19 with the burner trough 33 in combination.

In extension of the outer space part 31, that is, the annular channel formed by the inner wall 25 and the peripheral part of the outer wall 21 of the gas mixing head 38 is provided with a channel connection 41 to the fuel gas outlet 42, wherein the channel connection 41 inwardly through a gas mixing chamber 39 with the interposition of insulation 43 enclosing inner wall 44 and the radially spaced therefrom outer wall 45 of the upper housing part 4 is limited, so that results for the gas mixing head 38, and thus the upper housing part 4, in analogy to the peripheral part of the lower housing part 5, a Doppelschaligkeit that is used for the air duct , For branching off to the side of the fuel gas outlet 42 toward the channel connection 41, as part of the outer wall 45, projecting radially outward, a nozzle 46 in which, starting from the gas mixing chamber 39 then at the lining of a flame tube 47 extends over which the fuel gases Consumers, ie here to be heated zones of the oven, is supplied.

Between the nozzle 46 and the flame tube 47 remains an annular gap which is open to the outer space part 31 and to the lying in the extension channel connection 41, and over the supply air is supplied, which is mixed with the exiting fuel gases, in particular in the region of the flame tube 47. For this purpose, the flame tube 47, which is not shown, be provided with corresponding inlet cross sections or, for example, also be configured in such a way that at least over part of the circumference an annular gap results, which allows inflow of air into the flame tube 47. However, it is also within the scope of the invention to carry out the mixing of supply air and combustion gases leaving the flame tube 47 only in the area of the outlet cross section, which is preferably in the transition region to the oven, not shown, to which a connection piece 48 can be assigned, which is assigned to the connection piece 46 is to be fixed via a flange connection, preferably via a quick release flange connection.

With regard to the design of the crossing cross-section between the outer space part 31 and the channel connection 41, it may be appropriate, as indicated at 49, the flange connection between the upper housing part 4 and lower housing part 5 of the unit 1 to design like an iris, which is also due to inserted between the flanges aperture in easy to reach. Preferably, via the flange 36 between the burner trough 33 and the inner wall 25 of the inner space portion 29 in the upper region of the burner trough 33 is cross-sectionally closed, so that there is no short-circuit connection between the outer space part 31 and the inner space part 29 in the region of the annular gap 40. The flange connection 36 may be offset so far from the upper edge of the burner trough 33 that in addition to the annular gap 40 above the flange 36, the peripheral wall 34 of the burner trough 33 passing through inflow openings can be provided on the burner trough 33.

The transitional cross section from the burner trough 33 to the gas mixing chamber 39 is preferably constricted in the context of the invention, wherein this constriction can be realized by a retracted, not shown edge region of the burner trough 33, or by a projecting radially inwardly over the burner trough 33 part 50th the boundary of the gas mixing chamber 39.

Ausmündend on the gas mixing chamber 39 is the upper part 2 associated with a closable service opening 51, which is closed in the embodiment by a plug-like closure member 52 which is set in the simplest manner, for example by screwing and is to be inserted into a sleeve-like guide 53 of the upper part 2.

Preferably, along the upper part 2, a fuel supply 54 in the form of at least one downpipe 55 is then provided to a dosing device, not shown, which opens laterally obliquely from above on the upper portion of the burner trough 33 and the mouth side for flame shielding and / or distribution of the particular shape associated with pellets fuel supply corresponding shield members 56 are assigned.

On the burner trough 33, the air supply via partial air feeds, of which the first partial air feeds through the bottom 35 of the burner trough 33 associated openings 57 are formed. Analogously, partial air feeds formed by openings 58 are provided in the peripheral wall 34 of the burner trough 33, wherein the bottom-side openings 57 form first partial air feeds and the peripheral openings second partial air feeds and are respectively fed from the inner room part 29 demarcated as storage space 61. The representation of the openings 57, 58 as bores is symbolic, and instead of such bores, slots, inwardly and / or outwardly directed forms or the like may be provided which, with respect to the respective flow, form air ducts via which the air movement within the burner trough 33 is to be influenced, for example as helical or whirl-shaped, is to make upward against the gas mixing chamber 39 extending air flow.

Regarding the bottom side, illustrated by the opening 57 first partial air feeds guide plates 59 are illustrated in the embodiment, which are on the one hand suitable to influence the flow direction of the air entering through the openings 57, and also to achieve a shielding of the openings 57 against bottom-mounted fuel is so that blockages of the openings 57 are avoided.

In addition to the outgoing from the storage space 61 of the inner space part 29 first and second partial air feeds with the openings 57 and 58 third partial air supplies are provided, starting from the outer room part 31, these third partial air feeds, for example, and preferably through the annular gap 40, but optionally also by the 33 openings are formed associated with the upper edge region of the burner trough and wherein the vortex movement of the air in the sense of a spirally rising upward air flow can be enhanced via these third partial air supplies corresponding to the flow through the outer space part 31 in the burner trough 33. As a result, results against the gas mixing chamber 39, a cyclonic air vortex, which leads to a very intense burning with minimized pollutant emissions, including among other things, that the cyclonic air vortex in the center leads to a negative pressure, through which a part of the fuel gases from the gas mixing chamber 39 into the burner trough 33 is returned and there, with amplification of the rotating air movement, is deflected outwards again and flows into the cyclonic air vortex, which is derived from the gas mixing chamber 39 partially via the flame tube 47 to the fuel gas outlet 42, and it may also be useful in the invention to design the Ausströmweg from the gas mixing chamber 39 to the flame tube 47 so that the flame tube 47 to the gas mixing chamber 39 is approximately tangent, and not, as in the embodiment shown, radially. This in each case with the objective to detect the areas of the downstream oven to be heated as evenly as possible and so to achieve a uniform heating of the baking surfaces, for which purpose the whirling achieved surface fanning of the onflowing fuel gases significantly contributes.

In the context of the invention, the outer space part 31 also forms a connection of fourth partial air feeds to the blower chamber 24, the fourth partial air feeds preferably opening onto the flame tube 47, which is not shown.

In connection with the forced through the conveyor member 10 of the fan 8 rotating air movement through the downstream of the conveyor member 10 vertebral body 22, as in Fig. 4 illustrates disturbed and split into partial flows, resulting in particular in conjunction with the relation to the direction of rotation of the fan wheel 13 formed as conveying element 12 flat convex curvature of the blades 14 of the impeller 13 and a pressure build-up, so that pressure and flow-dependent a purpose different Air supply of the partial air supply is possible. In the context of the invention, it proves to be expedient starting from the storage space 61 via the first and second partial air feeds each about the same proportion of air of the burner trough 33rd introduce, wherein the air fraction supplied via the first and second partial air feeds preferably at a total of about 30%. About the third partial air feeds, in particular so the annular gap 40, preferably about 30 to 50% of the delivered air volume supplied, wherein the average value of about 40% forms a preferred value. For the fourth partial air guide, a percentage between about 20 and 30% is appropriate.

The described burner system works, also due to the long residence time of the fuel gases, very low in pollutants, and is characterized, with good meterability of the fuel supply, by a simple adjustability of the heating power and a low-residue combustion.

Claims (16)

1. Burner system, especially for ovens fired with bio-solid materials, which as a modular unit arranged in an upright manner comprises

   o a flammable gas outlet (42),

   o a burner trough (33) of a firing chamber (32), which trough is open to the flammable gas outlet (42),

   o a gas mixing chamber (39) which lies above the burner trough (33) between this and the flammable gas outlet (42), and

   o a blower unit (8) which lies beneath the burner trough (33), which blower unit accommodates a delivery element (10), with an upright rotational axis, in a blower chamber (24), and the blower chamber (24) of the blower unit, which has a suction opening (20) and is delimited in the direction of the burner trough (33), has an outflow opening (60), which is open towards the burner trough (33) and lies in the circumferential region of the delivery element (10), for a rotating air swirl which is created by the delivery element (10),
   characterized in that
   the outflow opening (60) leads to an accumulation chamber (61), the inner and upper limit of which is formed by the burner trough (33) which is arranged in a manner in which it is immersed in a transition chamber (30) which lies above the blower chamber (24), which burner trough has air passage openings (57, 58) which are open to the accumulation chamber (61) and which in first partial air feeds connect the accumulation chamber (61) to the burner trough (33) in the region of its bottom (35), in second partial air feeds connect the accumulation chamber (61) to the burner trough (33) in its circumferential wall (34) region which adjoins the bottom region, and in third partial air feeds connect the transition chamber (30) to the burner trough (33) in the boundary region which is remote from its bottom (35).
2. Burner system according to Claim 1,
   characterized in that
   the partial air feeds are partially associated with chamber sections (29, 31) of the transition chamber (30) which are separated from each other and have separate connections (annular gap 28; openings 37) to the blower chamber (24), wherein the first and the second partial air feeds originate from an inner chamber section (29) of the transition chamber (30) which forms the accumulation chamber (61), provision being made in an encompassing manner in relation to the inner chamber section for an outer chamber section (31) of the transition chamber (30), from which the third partial air feeds originate.
3. Burner system according to Claim 2,
   characterized in that the inner chamber section (29) and the outer chamber section (31) of the transition chamber (30) are separated via an annular inner wall (25) which is provided in an encompassing manner in relation to the firing chamber (32) and in relation to the blower chamber (24).
4. Burner system according to Claim 3,
   characterized in that the inner chamber section (29) of the transition chamber (30), which forms the accumulation chamber (61), is connected to the blower chamber (24) via the outflow opening (60) which, like an annular gap, is provided in the circumferential region in relation to a shielding wall (26) which lies in the transition between the accumulation chamber (61) and the blower chamber (24).
5. Burner system according to Claim 3 or 4,
   characterized in that the outer chamber section (31) of the transition chamber (30) is connected to the blower chamber (24) via a connection which is formed by means of circumferential-side openings (37) of the blower chamber (24).
6. Burner system according to Claim 5,
   characterized in that
   the circumferential-side openings (37) of the blower chamber (24) are formed by means of recesses in the annular inner wall (25).
7. Burner system according to one of Claims 2 to 6,
   characterized in that
   the accumulation chamber (61), which is formed by means of the inner chamber section (29) of the transition chamber (30), is delimited in the axial direction, ending at the connection of the outer chamber section (31) to the burner trough (33).
8. Burner system according to one of the preceding claims,
   characterized in that
   the transition chamber (30) is axially covered by a mixing head (38) which has a mixing chamber (39) which lies in a covering manner in relation to the firing chamber (32), the entry cross-section of the gas mixing chamber which faces the firing chamber (32) being constricted in diameter compared with the firing chamber (32).
9. Burner system according to Claim 8,
   characterized in that
   the gas mixing chamber (39) is connected to a flame tube (47) which is associated with the flammable gas outlet (42), and in that provision is made for an air feed, ending at the flammable gas outlet (42), which forms the fourth partial air feed and is connected to the blower chamber (24).
10. Burner system according to Claim 9,
    characterized in that
    the fourth partial air feed comprises a passage connection which is connected to the outer chamber section (31) of the transition chamber (30) and extends over the gas mixing head (38), which passage connection, in an encompassing manner in relation to the burner section (62) and in a covering manner in relation to the gas mixing head (38) which accommodates the gas mixing chamber (39), forms a double-shell casing with outer walls (21, 45).
11. Burner system according to one of the preceding claims,
    characterized in that
    the blower unit (8) has a delivery element (10) with a blower wheel (13) and with swirl bodies (22) which are provided in an extension of the vanes (14) of the blower wheel (13), extending on the circumferential side.
12. Burner system according to Claim 11,
    characterized in that
    the blower wheel (13) is provided with vanes (14) which extend in the direction of rotation in a flat curved manner and in the radial extension carry an attached swirl body (22) in each case.
13. Method for operating a burner system according to one of the preceding claims,
    characterized in that
    with regard to the air volume which is delivered by the blower unit (8), different air volumes are directed via the partial air feeds, and in that via the first to third partial air feeds about 50 to 80% of the delivered air volume is fed to the burner trough (33).
14. Method according to Claim 13,
    characterized in that
    the first and second partial air feeds are loaded with approximately equal portions of the delivered air volume.
15. Method according to Claim 14,
    characterized in that
    the first and second partial air feeds are together loaded with approximately 30% of the delivered air volume.
16. Method according to one of Claims 13 to 15,
    characterized in that
    the third partial air feeds are loaded with approximately 30 to 50%, preferably approximately 40%, of the delivered air volume.

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