The invention relates to a burner with surface burning, which has a fabric membrane on a housing on the burner side and comprises a flame flash-back barrier upstream of a burner side.
Such a burner is known from EP 0 628 146 B1. Such a gas burner has a fabric membrane on an outlet side of the housing which is formed as a gas-permeable metal fibre plate. This metal fibre plate is porous and additionally comprises through-holes which are arranged at regular distances to one another and form a hole pattern. The metal fibre plate is allocated to a distribution component in the housing. A fuel-air mixture is introduced into the housing via a supply line and flows through the distribution component, such that a flame field is formed after the through-holes in the metal fibre plate outlet are flowed through, said flame field having higher flames which are caused by a regular pattern of these through-holes. Such housings are, for example, formed to be square, as is depicted in FIGS. 1 and 2 of EP 0 628 146 B1. To fix the distribution component to the flame flash-back barrier, the metal fibre plate and the distribution component are applied to a front-side edge of the housing in order to subsequently put a clamping ring having a circulating shoulder over this, wherein this clamping ring is connected firmly to the housing with a welded joint.
A burner with surface burning emerges from EP 0 223 691 A1, in which a ceramic plate is fixed to a housing of burner by means of flange, wherein the flange engages with an outer periphery of the tubular housing. This flange is connected firmly to the tubular housing by a rivet, such that the burner plate is fixed unreleasably to the housing.
Such burners have the disadvantage that, in the case of damage to the fabric membrane and/or the distribution component, the entire burner must be replaced. Additionally, an alignment of a hole pattern of the fabric membrane with a hole pattern of the distribution component cannot occur.
The object of the invention is to propose a burner for surface burning in which cost-efficient maintenance is enabled and, on installation of a fabric membrane as well as a flame flash-back barrier, an alignment of the two parts with each other is enabled.
This object is solved by a burner with surface burning in which the fabric membrane and the flame flash-back barrier are able to be arranged in the housing using at least one releasable connection element which engages with a receiving space. Due to this releasable connection element, the fabric membrane and the flame flash-back barrier can be removed from the housing for replacement, such that, subsequently, the housing is equipped with a new flame flash-back barrier and/or fabric membrane. The fabric membrane can be removed for maintenance purposes. In the case of damage, the entire burner does not have to be exchanged. Additionally, the at least one releasable connection element, which is able to be arranged on or fixed to the housing, has the advantage that an alignment of a hole pattern of through-holes in the fabric membrane with a hole pattern of through-bores in the flame flash-back barrier is enabled before fixing the releasable connection element in the housing and thus before fixing the fabric membrane and the flame flash-back barrier to each other.
The housing of the burner can be formed to be tubular and can comprise a receiving region having an inner peripheral surface, with which at least the fabric membrane and/or the flame flash-back barrier are guided radially or laterally. Thus, a simple alignment to each other and adjustment can be enabled after the insertion of the flame flash-back barrier and/or the fabric membrane, solely by a rotational movement of the flame flash-back barrier.
At least the fabric membrane and/or the flame flash-back barrier are able to be adjusted in their position with respect to each other or in the alignment of the hole patterns and are held in a braced manner by the releasable connection element. Thus, the aligned or adjusted position of the fabric membrane with respect to the flame flash-back barrier relative to the respective hole patterns thereof are fixed inside the housing in a simple way.
Astonishingly, it has been shown that, for example, in the case of an aligned arrangement of the through-bores of the flame flash-back barrier with the through-holes of the fabric membrane, an optimised flame matrix can be formed. Such a flame matrix consists of individual flames and a support flame, wherein the individual flames protrude from the support flame. Due to the aligned arrangement, a good flow cooling of the fabric membrane and at the same time a cooling of the flame root of the individual flames are enabled. Thus an increased surface loading of the fabric membrane can be achieved, which means that an increase in performance is provided with respect to previous burner performances.
Furthermore, due to this arrangement it is enabled that the hole pattern of the fabric membrane is able to be positioned in a twisted and/or displaced arrangement with respect to the hole pattern of the flame flash-back barrier. Thus so-called flame nests can be formed. “Flames nests” are understood to be a group of individual flames within a flame matrix which are not all aligned in parallel to one another and extend at a right angle to the surface of the fabric membrane into the combustion chamber, but rather at least one central main flame is directed as an individual flame into the combustion chamber and this comprises several surrounding individual flames which are inclined with respect to this at a deflection angle to the main flame. Thus a detuning, i.e. a reduction of occurring resonances, can be achieved, whereby noise reduction is achieved for the surface burning. Due to the releasable connection element, an adaptation and adjustment of the fabric membrane with respect to the flame flash-back barrier or vice versa can thus be carried out directly on site for a least one particularly specific environmental condition.
A pre-determined distance is preferably generated by a spacer element between the fabric membrane and the flame flash-back barrier, such that a free flow chamber of the fuel-air mixture results between the flame flash-back barrier and the fabric membrane. This spacer element preferably has the same outer periphery as the fabric membrane and/or the flame flash-back barrier, such that these components are able to be inserted together and one after another into the receiving region of the housing and therein are guided radially. The spacer element can, for example, be formed as a heat-resistant ring which preferably has contact surfaces aligned axially on both sides.
According to one preferred embodiment of the burner, the at least one releasable connection element is provided upstream of the flame flash-back barrier. This arrangement has the advantage that the releasable connection element is on the so-called “cold side”, i.e. the flame flash-back barrier is not on the burner side, but rather on the supply side. The fuel-air mixture is supplied on the supply side and achieves cooling due to the flow, such that a long service life is achieved for the releasable connection element.
The receiving region can be limited downstream by an annular shoulder pointing towards the longitudinal central axis of the housing and upstream by the releasable connection. This enables a simple insertion of the fabric membrane and subsequently of the flame flash-back barrier into the burner housing from behind. Subsequently, after the insertion and alignment of the fabric membrane and the flame flash-back barrier, the releasable connection element can be fixed. This represents a constructively simple and cost-efficient design of the burner head.
One alternative embodiment for the formation of the releasable connection element can represent the formation of a screw connection between a flame tube and a burner housing. According to a first embodiment, the fabric membrane and the flame flash-back barrier are held in a clamped manner in the receiving space of the burner housing between the burner housing and the flame tube.
One advantageous embodiment of the screw connection can provide that the burner housing and the flame tube are connected to each other by the screw connection and the flame tube preferably has an external thread and the burner housing an internal thread. Thus, a front-side end of the burner housing can form a contact surface for the flame flash-back barrier and at least the fabric membrane and the flame flash-back barrier can be clamped in between these by screwing the flame tube to the shoulder arranged thereon on the burner housing.
Due to an elongation as a spacer, preferably having an internal and external thread, the burner housing can be elongated by any amount, wherein the elongation is positioned between the burner housing and the flame tube.
One alternative embodiment of the releasable connection is provided in that the fabric membrane and, if necessary, also a spacer element are received in a clamped manner and a further releasable connection element is provided upstream of the screw connection, with which the flame flash-back barrier is fixed. This further releasable securing element can be formed as a circlip or clamping ring which is inserted into a circulating groove in the burner housing.
One further alternative embodiment of the burner provides that the releasable connection element is able to be arranged upstream and downstream of the receiving region. This arrangement enables the use of a tube as a housing, whereby a cost-efficient design for larger flame tube diameters of over 300 mm is enabled.
Alternatively, the housing can be formed in the tubular housing for the formation of the receiving region upstream of the receiving space by a circulating beading which is directed towards the central axis. In this embodiment, prefabricated tubes can be used as the housing, in which a beading is introduced in a simple way by a rolling process in order to limit the receiving region upstream.
In the case of the housing formed from a tube in a circulating beading, an inner clamping ring is preferably provided for fixing the flame flash-back barrier and the fabric membrane as well as the spacer element, said inner clamping ring preferably being arranged therebetween, said inner clamping ring enabling a clamping fixing in the tube without additional processing of the inner peripheral surface. Alternatively, provision can furthermore be made for two tube sections which are placed one inside the other to form the housing, wherein the tube sections are preferably connected firmly to each other and an inner tube section forms a shoulder.
The tubular housing into which a beading can be introduced preferably consists of a drawn or welded tube.
Preferably, for the production of the housing, a heat-resistant material, in particular a steel, stainless steel or grey cast iron, can be used as a rotating part. For a so-called wet operation, stainless steel is used, whereas for a dry operation both steel and grey cast iron can be used.
The releasable connection element can be formed according to a first cost-efficient embodiment as a circlip which is able to be inserted into a circulating groove in the inner peripheral surface of the receiving region on the housing. Such circlips or snap rings can be formed from heat-resistant material and can be assembled and disassembled simply.
One alternative embodiment for a releasable connection element is provided by an inner clamping ring, which is braced against the inner peripheral surface of the receiving region by radial expansion. Such inner clamping rings or clamping clips enable a fixing without additional processing of the inner peripheral surface.
The housing having the shoulder which points inwards is preferably formed as a rotating part according to a first embodiment. Thus a cost-efficient production of a one, two or multi-part housing can be provided.
One further preferred embodiment of the burner provides that at least one ignition electrode and at least one monitoring electrode are fixed on an outer side of the housing, the electrode tips of which extend into a flame matrix formed downstream on the fabric membrane or adjacently to this. In particular in the case of smaller burner housings, ignition and monitoring from outside is provided.
Alternatively, in the case of burners having a larger flame matrix, it can be provided that the at least one ignition electrode and/or at least one monitoring electrode, which are preferably received by a mutual electrode holder, are able to be fixed in a through-opening in the fabric membrane. Thus, an interior positioning of the at least one ignition electrode and/or monitoring electrode can be provided. This additionally has the advantage that, in the case of large surfaces of the fabric membrane, an additional fixing of the fabric membrane is enabled in order to receive this fabric membrane with little or no oscillation.
The burner according to the features described above is preferably used as a flat burner, meaning that the surface burning occurs adjacently to a combustion chamber without the burner itself substantially protruding into the combustion chamber.
The invention as well as further advantageous embodiments and developments of the same are described and explained in more detail below by means of the examples depicted in the drawings. The features to be gleaned from the description and the drawings can be applied individually or together in any combination according to the invention. Here are shown:
In
At least one ignition electrode 24 and at least one monitoring electrode 25 are arranged on an outer side of the housing 14 or of the burner head 12. Furthermore, on the outer side of the burner head 12, a boiler cover 20 is provided, with which an opening of the boiler which is not depicted in more detail and the combustion chamber thereof is able to be closed.
In
The receiving space 47 in the housing 14 comprises an inner peripheral surface 49 which is limited on the burner side by a circulating shoulder which is preferably formed integrally on the housing 14. On the side of the fan, the inner peripheral surface 49 is limited by a groove 52. In the receiving region 47, the fabric membrane 16, the spacer element 48 and the flame flash-back barrier 17 are guided and positioned radially by the inner peripheral surface 49. Due to a releasable connection element 54 which is able to be inserted into the groove 52, the fabric membrane 16, the spacer element 48 and the flame flash-back barrier 17 are positioned and fixed with respect to the shoulder 51 in the receiving region 57. The releasable connection element 54 is, for example, formed as a clamping ring or circlip which is able to be inserted into the groove 52.
With this embodiment, the fabric membrane 16, the spacer element 48 and/or the flame flash-back barrier 17 are arranged in the housing 14 to be able to be exchanged individually. For the assembly, for example, the fabric membrane 16 is firstly inserted on the side of the fan, such that this abuts on the shoulder 51 with a burner-side surface and is fixed in the axial direction. A radial front surface of the fabric membrane 16 abuts on the inner peripheral surface 49, such that the fabric membrane 16 is guided radially in the receiving region 47 or is able to be rotated around the longitudinal central axis 37 of the housing 14. Following this, the spacer element 48 can be inserted, the outer peripheral surface of which also abuts on the inner peripheral surface 49 of the receiving region 27. Following this, the flame flash-back barrier 17 is inserted, which abuts on an axial front surface of the spacer element 48 with the front side which points towards the fabric membrane 16. The flame flash-back barrier 17 is also guided with its radial front side through the inner peripheral surface 49 in a radially rotatable manner with respect to the longitudinal central axis 37. Following this, the releasable connection element 54 is introduced into the receiving region 47 in the burner head 12 on the fan side and, for example, is positioned in a groove 52. Here, the fabric membrane 16, the spacer element 48 and the flame flash-back barrier 17 are positioned under low pre-tensioning with respect to one another and are pressed against the shoulder 51, such that a fixed-position arrangement of at least the fabric membrane 16 and the flame flash-back barrier 17 is provided in the receiving region 47 and is maintained by the releasable connection element 54.
The construction of the fabric membrane 16 emerges from DE 10 2010 051 415.2 which is referred to in its full scope and is the subject matter of this application. This burner fabric or this fabric membrane 16 enables a combustion process which is described in DE 10 2010 051 414.4, which is also referred to in its full scope and is the subject matter of this application.
The fabric membrane 16 has a hole pattern which comprises a plurality of through-holes 32 that are arranged at regular distances to one another. The flame flash-back barrier 17 likewise comprises a hole pattern having through-bores 33 which preferably have half the spacing of the through-holes 32 of the fabric membrane.
Due to the releasable connection element 54, an alignment of the hole pattern of the fabric membrane 16 with the hole pattern of the flame flash-back barrier 17 is enabled before the insertion of the releasable connection element 54, and due to the releasable connection element 54, a position fixing of the fabric membrane 16 and flame flash-back barrier 17 in the receiving region 47 with respect to one another is maintained after the alignment of the fabric membrane 16 to the flame flash-back barrier 17.
The housing 14 is formed integrally and is produced, for example, as a rotating part. The housing 14 is connected to a connection element 57 via a screw connection 56, which leads, for example, to the fan 19. This connection element 57 is, for example, formed as a bump turn. A connection plate 58 to receive and position the ignition electrode 24 and monitoring electrode 25 is provided on an outer side of the housing 14.
An alternative embodiment of the burner 11 to
An elongation 70 can be provided between the burner housing 61 and the flame tube 60, which preferably also comprises a screw connection as a releasable connection element 54. The releasable connection element 54 can alternatively also be formed as a plug connection, a clamping connection or a flange connection.
The embodiments according to
A further alternative embodiment to
In this embodiment, a tube can be used as a housing 14 which requires only the attachment of two grooves 52 on the inner periphery in order to position and fix the fabric membrane 16 and the flame flash-back barrier 17 therebetween.
The housing 14 can consist of a drawn or rolled or welded sheet metal material which is heat-resistant.
In
In this embodiment according to
In
In deviation from this, in this embodiment of the burner head 12 in comparison to the burner head 12 according to
These embodiments of the burner 11 according to
Furthermore, a distributor body 71 is provided in the housing 14, which has a conical or roof-like contour which is aligned to be pointing upstream. This distributor body 71 is fixed via retaining elements 72 at a distance to the base 69. An open jet of the fuel-gas mixture entering via the supply line 18 flows along the conical surfaces of the distributor body 71 radially outwards, whereby it causes a pressure and/or mixture distribution of the supplied fuel-air mixture to occur inside the housing 14, such that an even loading of the flame flash-back barrier 17 and the fabric membrane 16 is enabled.
The receiving space 47 in the above embodiments is preferably formed to be cylindrical, such that the fabric membrane 16 and the flame flash-back barrier 17 which are able to be arranged therein are able to be adjusted in their position with respect to one another in a simple way by rotation around the longitudinal central axis 37.
Due to the use of the at least one releasable connection element 54, not only can a cost reduction be achieved for the maintenance, but at the same time the reduction of the noise due to the formation of flame nests is also achieved, which is able to be adjusted with respect to an aligned arrangement of the hole patterns of the fabric membrane 16 and flame flash-back barrier 17 by a twisted arrangement of the hole pattern of the fabric membrane 16 with respect to the hole pattern of the flame flash-back barrier 17.
Number | Date | Country | Kind |
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20 2012 102 437.3 | Jul 2012 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2013/060033 | 5/15/2013 | WO | 00 |