EP4450870B1 - Vormischbrenner - Google Patents

Vormischbrenner

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Publication number
EP4450870B1
EP4450870B1 EP24187758.8A EP24187758A EP4450870B1 EP 4450870 B1 EP4450870 B1 EP 4450870B1 EP 24187758 A EP24187758 A EP 24187758A EP 4450870 B1 EP4450870 B1 EP 4450870B1
Authority
EP
European Patent Office
Prior art keywords
burner
openings
distributor
flame
zone
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP24187758.8A
Other languages
English (en)
French (fr)
Other versions
EP4450870A1 (de
Inventor
Domenico Peserico
Marco MUNARETTO
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Polidoro SpA
Original Assignee
Polidoro SpA
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Filing date
Publication date
Application filed by Polidoro SpA filed Critical Polidoro SpA
Publication of EP4450870A1 publication Critical patent/EP4450870A1/de
Application granted granted Critical
Publication of EP4450870B1 publication Critical patent/EP4450870B1/de
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/02—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2203/00—Gaseous fuel burners
    • F23D2203/10—Flame diffusing means
    • F23D2203/101—Flame diffusing means characterised by surface shape
    • F23D2203/1012—Flame diffusing means characterised by surface shape tubular
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2203/00—Gaseous fuel burners
    • F23D2203/10—Flame diffusing means
    • F23D2203/102—Flame diffusing means using perforated plates
    • F23D2203/1023—Flame diffusing means using perforated plates with specific free passage areas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2203/00—Gaseous fuel burners
    • F23D2203/10—Flame diffusing means
    • F23D2203/106—Assemblies of different layers

Definitions

  • the present invention relates to a premix burner for burning a mixture of a fuel and an oxidizer.
  • Burners of this type are frequently used in boilers for domestic heating and have a casing with a typically circular cross-section, on the surface of which flames are generated by burning a mixture generally obtained by mixing air and gas in a predetermined quantity ratio.
  • this ratio for which the mass of fuel present in the mixture reacts completely with the mass of oxidizer is defined as stoichiometric; values of the ratio greater than the unit, i.e., values for which the quantity of air is in excess with respect to the stoichiometric ratio, are defined as hyperstoichiometric.
  • the optimal value of the ratio, usually used in domestic boilers, is equal to about 1.3: this value is therefore hyperstoichiometric and allows limiting the level of harmful emissions, with respect to the level obtained at the stoichiometric ratio, and at the same time obtaining a good efficiency.
  • the prior art provides for adjusting the quantity of air to be mixed with the gas by means of suitable pneumatic adjustment systems.
  • patent EP 1 036 984 B1 proposes to increase the intensity of the flames in the zone of the burner in front of which the ionization electrode is located.
  • a solution similar to that illustrated in patent EP 1 036 984 B1 is proposed in patent application EP 0 339 499 A2 (see in particular Figure 3 of the latter document).
  • Thermal gradients are emphasised when a burner is used in modulation regime, i.e., when the required thermal power is dynamically changed.
  • EP 0 774 623 A1 describes a box-shaped burner having a burner deck formed by a series of separate deck parts that are movably supported by a housing and intermediate bridges, wherein the deck parts are made of mesh material.
  • This known burner comprises a pressure distributing plate arranged under the burner deck and is provided with spacing means holding the plate at a fixed distance from the burner deck.
  • the distribution zone and the flame zone are disposed opposite each other: in other words, the distribution zone and the flame zone face each other.
  • the expression specific flow rate denotes the volumetric flow of mixture through the unit surface (i.e., through a surface with a surface area of one square meter) per unit time (that is, in a second) and it is therefore measured in m 3 /(m 2 ⁇ s): the specific flow rate thus has the dimensions of a velocity (m/s).
  • the burner according to the present invention differs from the burners described in the aforementioned documents EP 1 036 984 B1 and EP 0 339 499 , in which a flat perforated burner ( Brennerplatte, in the original German terminology of the two documents) is disposed on top of a mixture duct.
  • the mixture is not distributed by means of a distributor located inside the burner but flows directly from the duct through the holes of the flat burner, on the outer surface of which flames are formed during the combustion of the mixture itself.
  • a distributor is located inside the casing of the burner and is separated from the latter by an air gap: as a result of this arrangement, the mixture leaving the distributor reaches the flame openings only after passing through the internal distributor and the air gap itself.
  • spacing elements are disposed in the air gap between the internal distributor and the outer casing; the spacing elements are preferably integral with the distributor.
  • a further advantage of the technical solution adopted in the burner according to the present invention is that the already mentioned and expensive metal meshes capable of withstanding high temperatures are not used.
  • the absence of such meshes in addition to allowing a significant reduction in the production costs of the burner, advantageously allows avoiding the formation of gas pockets, typically present between the mesh and the casing of known burners, and also improves the operating stability of the device, the behaviour of which is no longer subject to variations due to the flexibility of the meshes used in the prior art.
  • Figures 7A and 7B show the behaviour of the ionization curves measured respectively for a burner according to the invention and for a conventional burner as the thermal flow rate varies, for a mixture of air and gas of the G20 family (methane; curve with diamonds) and a mixture of air and liquid propane gas (LPG; curve with squares).
  • Figure 7A relating to a burner according to the present invention, the trend of the ionization current as the thermal flow rate Q varies is qualitatively identical for the two mixtures.
  • the ionization curve relating to the air and gas mixture of the G20 family has a behaviour that is very different from that relating to the air and LPG mixture: while the first curve is substantially flat, the second curve has a peak in the region of low flow rates, around 3.5-4 kW, and then falls to significantly lower values than the first curve on the rest of the range of thermal flow rates.
  • the burner according to the present invention is also characterised by a high slope and by the monotony of the sensitivity curve, that is, the function that describes the trend of the ionization current as the air-gas ratio ( ⁇ ) varies, for a predefined value of the number of revolutions per minute of the fan supplying air for the mixture (i.e., for a fixed thermal flow rate value).
  • the sensitivity may feature the so-called "inversion", i.e., a region where the curve has an inflection point and in which two values of the ratio ⁇ correspond to an ionization current value, which results in the electronic control system for controlling the ratio value having difficulties in properly adjusting the boiler operation.
  • the dimensions of the detection portion in the first and the second direction are selected so as to be smaller than the corresponding dimensions of the distributor in the same directions: the detection portion therefore occupies a region of the distribution zone on the surface of the distributor with a surface area smaller than that of the zone itself and limited in two perpendicular directions, respectively coinciding with the first and the second direction.
  • the detection portion allows increasing locally the flow of mixture which, through the surface of the distributor, reaches the outer casing. At the circumscribed region in which the flow is thus "amplified", the flames develop with greater intensity than in the rest of the device and generate, in any operating regime of the burner, an ionization signal of such an intensity as to be easily detectable, for example by means of an ionization electrode known per se, thus allowing a reliable adjustment of the air-gas ratio.
  • the local increase in the specific flow rate in the detection portion can be advantageously achieved by adjusting the ratio between the sum of the surface areas of the flow openings formed on the surface of the distributor and the total surface area of said portion, so that it is greater than the ratio between the sum of the surface areas of the openings in the rest of the distribution zone and the surface area of said rest.
  • the local increase in the specific flow rate can be advantageously controlled by adjusting the porosity of the detection portion with respect to the porosity of the rest of the surface of the distributor.
  • the surface area of the flow openings can be controlled in a precise and repeatable manner and since these openings are formed on the surface of the distributor by means of high precision mechanical processing, with the present invention it is possible to guarantee a reliable and stable adjustment of the ionization signal and, consequently, a stable behaviour of the burner itself.
  • the surface area of each of the flow openings present in the detection portion on the surface of the distributor is greater than the surface area of each of the flame openings on the combustion surface of the outer casing. Since the zone in which the flame openings are disposed, that is, the so-called flame zone, is disposed in front of the detection portion in which the flow openings are disposed, the increased surface area of the latter with respect to the surface area of each flame opening causes the flow leaving each flow opening to be distributed between several flame openings, instead of reaching a single flame opening. In this way it is possible to create a bed of sealing flames on the surface of the burner and the phenomenon of flame detachment is advantageously avoided.
  • the flow openings and the flame openings are chosen with circular shape, it becomes particularly simple to adjust the relative ratio between the surface area of each flow opening and the surface area of each flame opening, because in this case it is sufficient to adjust the diameters of the respective openings when manufacturing the distributor and the outer casing.
  • the use of circular openings therefore allows controlling the operation of the burner in a particularly reliable, simple and economical way.
  • the diameter of the flame openings is preferably less than 1.5 mm; this value advantageously reduces the phenomenon of backfire.
  • the flow openings and the flame openings can advantageously be disposed evenly on the surface of the distributor and on that of the outer casing of the burner, for example, by arranging the flow openings according to a periodic pattern having a first spacing i.e., pitch) P1 and the flame openings according to a periodic pattern having a second spacing i.e., pitch) P2, different from the first spacing and preferably smaller.
  • the arrangement of the openings according to a periodic pattern is particularly advantageous in terms of manufacture, since these openings are formed by repeatedly perforating a metal strip, usually made of steel, from which two perforated portions are then cut which are intended to form the distributor and the outer casing, by means of programmable mechanical machines which perform a stepwise machining of the strip: the manufacture of regular patterns can in fact be obtained by simply setting the advancement pitch of the machine equal to the value of the first or second spacing (i.e., pitch) of the periodic pattern.
  • the objects of the present invention can be achieved also by means of periodic patterns which have two different spacings in two different directions: for example, the flow openings can be disposed according to a periodic grid with a spacing P1 in a first direction (for example, in the case of a cylindrical burner, in the tangential direction, i.e. along the circumference of the cylinder) and with a spacing (i.e., pitch) P1', different from the spacing (i.e., pitch) P1, in a second direction different from the first one (for example, in the case of a cylindrical burner, in the axial direction).
  • a spacing P1 in a first direction for example, in the case of a cylindrical burner, in the tangential direction, i.e. along the circumference of the cylinder
  • a spacing (i.e., pitch) P1' different from the spacing (i.e., pitch) P1
  • the flame openings can be disposed according to a periodic grid with a spacing (i.e., pitch) P2 in a first direction and a spacing P2' (i.e., pitch), different from the spacing P2, in a second direction different from the first one.
  • a spacing i.e., pitch
  • P2' i.e., pitch
  • the objects of the present invention can also be achieved by non-regular and non-periodic distribution of the flow and/or flame openings, provided that the distributor and the outer casing are kept spaced apart by means of an air gap and provided that an increased specific flow rate detection portion is formed on the surface of the distributor, as explained above.
  • the thickness of the air gap must be different from zero; preferably, the thickness of the air gap is less than 4 mm and, even more preferably, this thickness is chosen equal to 0.6 mm.
  • the presence of an air gap of non-zero thickness improves the distribution effect of the mixture leaving each flow opening on several flame openings and thus reduces the phenomenon of flame detachment; the value of 0.6 mm has proved experimentally optimal in reducing this phenomenon.
  • the burner subject matter of the present invention is advantageously used in boilers provided with a combustion chamber, preferably in combination with a detection electrode for detecting the ionization signal generated by the flames that develop on the surface of the burner, when the mixture is burned.
  • the present invention also relates to a method for adjusting the flow intake of a mixture of oxidizer and fuel in a premix burner as described above.
  • the method comprises the following steps:
  • FIG 1 shows an exploded view, purely by way of example, of a premix burner (100) according to a preferred embodiment of the present invention.
  • the burner comprises an outer casing (3) provided on its surface (31), called combustion surface, with openings (33) called flame openings; the combustion surface (31) represents the surface on which, during the operation of the burner (100), flames develop, in particular at the flame openings (33).
  • the region of the combustion surface (31) on which the flame openings (33) are present substantially constitutes the so-called flame zone.
  • the outer casing (3) has a cylindrical shape and is provided with circular openings (33); it is understood that the objects of the present invention can also be achieved by means of outer casings of different shape, for example in the form of a parallelepiped, and by using flame openings (33) with a shape different from the circular one, for example elongated slits; such slits may be combined with circular openings and may be distributed on the combustion surface according to periodic or uneven geometric patterns, depending on the desired flame distribution.
  • the flame openings (33) can be distributed on the combustion surface (31) along the axial direction of the cylindrical casing (3) in zones having different geometrical patterns: for example, the diameter of the openings (33) and/or the distance between them within each zone may be different from the diameter and distance in each - or even in some - of the other zones.
  • the criteria for selecting the dimensions are known to those skilled in the art and will not be repeated here.
  • the flame openings (33) are circular holes with a diameter of 0.6 mm, repeated periodically both in the tangential direction and in the axial direction of the cylindrical casing (3).
  • the holes (33) are disposed periodically in sequence along the tangential direction at a mutual distance (pitch or spacing) equal to 1.4 mm; sequences of adjacent holes (33) in the axial direction are staggered along the tangential direction; the periodic distance in the axial direction between adjacent hole sequences (33) is 1.2 mm.
  • the outer casing (3) of the burner (100) is disposed around a distributor (2), located inside the outer casing (3) itself; in the example of Figure 1 the distributor (2) (to which reference will also be made with the expression internal distributor ) also has a cylindrical shape and is disposed coaxially with the outer casing (3), as can be appreciated from Figure 3 , in which the outer casing (3) is partially raised with respect to the distributor (2) and allows the lower part of the latter to be seen.
  • the distributor (2) can also have other geometrical shapes: for example, in the aforementioned case of a parallelepiped-shaped outer casing (flat burner), the internal distributor (2) also preferably has the shape of a parallelepiped, contained inside the largest parallelepiped that forms the outer casing.
  • the outer casing (3) is manufactured from a flat strip which is perforated by means of a punching machine, so as to provide the desired spatial distribution of flame openings (33); in the case of a cylindrical outer casing, the flat strip, once perforated, is folded onto itself to form the cylindrical casing (3).
  • the outer casing (3) shown in Figure 1 has a homogeneous spatial distribution of flame openings (33), other distributions can be applied.
  • Figure 6 shows a flat strip, usable for manufacturing a cylindrical outer casing, characterised by a distribution of flame openings (33) that is gradually less dense in the axial direction running from the base (34) of the casing (3) towards the top (32) of the casing (3) itself.
  • the base (34) of the casing (3) is close, in the mounted burner, to a flange (12), while the top (32) is adjacent to a cap (4) which closes the cylindrical casing (3).
  • the gradual reduction in the density of openings (33) along the surface (31) of the outer casing (3) it is possible to reduce the deformations of the outer casing (3) due to the abrupt passage from a perforated region, i.e., the flame zone provided with flame openings (33), to a region without perforations.
  • a perforated region i.e., the flame zone provided with flame openings (33)
  • an abrupt transition between the flame zone and the zone without perforations creates a sudden thermal gradient, due to the fact that the flames essentially develop only in the flame zone, and can therefore cause deformations.
  • the gradual reduction in the densities of openings (33) along the surface (31) of the outer casing (3) can be obtained in the opposite direction to that illustrated in Figure 6 , i.e., going from the top (32) towards the base (34).
  • the distributor (2) has on its surface (21) (called distribution surface) a plurality of openings (23, 26), called flow openings; in the example of Figure 4 , these openings have a circular shape.
  • the region of the distribution surface (21) on which the flow openings (23, 26) are present substantially makes up the so-called distribution zone.
  • the main function of the distributor (2) is to allow the passage and the spreading of a fluid mixture fed into the burner (100) towards the combustion surface of the burner, coinciding with the combustion surface (31) of the aforementioned outer casing (3).
  • the mixture typically consisting of air and gas, is fed through one or more openings (11) disposed on the surface of a head (1) located at the base of the burner (100), as can be seen from the exploded view of Figure 1 , and fixed to the latter by means of a flange (12), shown in perspective view in Figure 1 and in side view in Figure 4 .
  • both the internal distributor (2) and the outer casing (3) of the burner (100) are fixed to the head (1).
  • the number, shape and dimensions of the feeding openings (11) present on the head (1) and their spatial distribution can be determined by the person skilled in the art on the basis of commonly known design principles.
  • the distribution of the openings (23) on the surface of the distributor (2) can be determined - except for the openings (26) in the detection portion (200) - according to the teachings of the European patent EP 1 914 476 B1 of which the Applicant of the present application is the owner.
  • the flow openings (23) have a circular shape and, except for the aforesaid detection portion (200), partially hidden in the figure by an electrode (5) described below and used to detect an ionization signal, these openings are distributed evenly on the distribution surface (21) with constant spacing and diameter.
  • the flow openings (26) are geometrically configured in such a way that the specific flow rate of mixture flowing through the detection portion (200) is greater than in the remaining parts (201, 202) of the distribution zone, that is, in the rest of the distribution surface (21), in which flow openings (23) are present, which is formed in the example shown in the figure by two regions denoted by the numerals 201 and 202.
  • specific flow rate q is the volumetric flow of mixture passing through the unit of surface (i.e., a surface with an area of one square meter) in the unit time (i.e., in one second).
  • the detection portion (200) is a region of narrow and elongated shape along the axial direction of the distributor (2) and within which the flow openings (26), with circular shape in the example, have a greater diameter than the flow openings (23) in the rest (201, 202) of the distribution zone.
  • the increased dimension of the flow openings (26) in the detection portion (200) facilitates the passage of the mixture in this portion and therefore increases the specific volume of mixture which reaches, in the unit time, the combustion surface (31) of the outer casing (3) (not visible in Figure 4 ), where it is burned on the flame openings (33) during the combustion process.
  • the increased dimension of the flow openings (26) in the detection portion (200) thus produces locally more intense flames on the part of the combustion surface (31) overlying the underlying detection portion (200).
  • the local increase in the mixture flow in the detection portion (200) is achieved if the ratio between the sum of the surface areas of the flow openings (26) present in the aforesaid detection portion (200) and the total surface area of that portion (200) is greater than the ratio of the sum of the surface areas of the openings (23) in the rest (201, 202) of the distribution zone and the total surface area of the remaining distribution zone.
  • the local increase in the mixture flow is ensured if the local porosity ⁇ R in the detection portion (200) is greater than on the rest (201, 202) of the distribution surface (21).
  • porosity is used in accordance with its usual meaning in the technical field of burners and generally indicates, with reference to a surface with openings or "voids", the ratio between the sum of the empty surface areas and the total surface area of the surface.
  • the porosity can be increased in different ways by acting on the geometric configuration of the flow openings: it is possible, in the case of circular openings disposed evenly, to increase the diameter of each flow opening (26) in the detection portion (200) with respect to the diameter of the openings (23) in the rest (201, 202) of the distribution zone, as shown in Figure 4 ; again in the case of circular openings disposed evenly, it is possible alternatively to maintain unchanged the diameter of the flow openings (26), increasing instead the density thereof (i.e. reducing the pitch) in the detection portion (200) with respect to the rest of the distribution zone.
  • the objects of the present invention can also be achieved by disposing the flow openings in the detection portion (200) and/or on the rest (201, 202) of the distribution surface (21) in an uneven manner, provided that the condition that the specific flow rate of mixture in the detection portion (200) is greater than on the rest (201, 202) of the distribution zone is ensured.
  • the intensity of the flames that develop on the part of the flame surface (31) of the outer casing (3) covering the aforesaid portion (200) is always greater than on the rest of the flame surface (31); as a result, the intensity of the ionization signal detectable near this part of the flame surface (31) by means of the detection electrode (5) is greater than at the rest of the flame surface, since the intensity of the ionization signal is directly proportional to the intensity of the flames.
  • the method for adjusting the flow intake of mixture according to the present invention comprises the following steps:
  • the control device can be, for example, a valve that regulates the inflow of gas into the chamber in which the air is premixed with the gas, before being fed into the burner (100) through the head (1).
  • the predetermined value of the ratio ⁇ depends on the type of oxidizer and fuel used: in general words, this value is chosen equal to the so-called stoichiometric value, i.e., the value for which the combustion reaction of the fuel is complete and does not produce residues, such as carbon monoxide, in the case of a fossil-gas fuel.
  • the dimensions of the detection portion (200) are chosen according to the dimensions of the detection electrode (5), so as to concentrate the increased flow of mixture in a region disposed in front of the electrode (5) and thus increase the sensitivity of the measurement of the ionization signal detected by the electrode itself.
  • the ionization electrode (5) usually has an elongated shape, as can be seen from Figures 1 , 4 and 5
  • the detection portion (200) typically also has an elongated shape in a first direction, essentially parallel to the projection of the electrode (5) on the outer surface (31) of the burner.
  • the shape of the detection portion (200) is not limited to an elongated shape and may, by way of example, be square.
  • the dimension of the detection portion (200) in the first direction is smaller than the dimension of the distributor (2) in the same direction; the dimension of the detection portion (200) in a second direction perpendicular to the first dimension is also limited and is smaller than the corresponding dimension of the distributor in the same direction.
  • the detection portion (200) can extend, for example, in a direction parallel to the length of the electrode (5) - hence parallel to the axis of the burner (100) - over a section of height L of the distribution surface (21), while the dimension of the portion in the direction perpendicular to the electrode, that is, the width W of the distribution portion (200), may be equal to 3D.
  • the length and width of the distribution portion (200) are smaller than the corresponding dimensions of the distributor (2).
  • the detection portion (200) is limited to a region with smaller dimensions than the corresponding dimensions of the distributor (2) in the two directions mentioned above.
  • the detection portion (200) extends in height (i.e., in the direction of the axis of the burner along which the mixture spreads) along a shorter section than the total height of the distributor (2): as can be seen from the figure, the internal distributor (2) also extends in a lower zone located below the regions 200, 201 and 202 and without, in the example, flow openings (23) and (26).
  • Figure 4 also shows that the detection portion 200 is also limited in width, i.e., in the circumferential direction of the cylinder (2).
  • the objects of the present invention can also be achieved by using a detection portion whose height is different from that of the remaining parts (201, 202) of the distribution zone.
  • the distribution zone is defined as the part of the distribution surface (21) provided with flow openings (23, 26): therefore, in the example of Figure 4 , the distribution zone corresponds substantially to the regions 200, 201, 202 disposed above the lower part of the surface (21) without openings (the so-called blind zone ).
  • the internal distributor (2) is separated from the outer casing (3) of the burner (100) by an air gap (300) of non-zero thickness G.
  • the thickness G is preferably less than 4 mm: in the example shown in the figure, G is equal to 0.6 mm.
  • the air gap (300) is empty and contains air.
  • a flame bed of non-zero thickness is created on the combustion surface (31) thanks to the distribution of the mixture leaving each flow opening (23, 26) over several flame openings (33), which flame bed contributes to the reduction of the phenomenon of flame detachment.
  • the value of the thickness G equal to 0.6 mm has proved experimentally optimal in reducing this phenomenon.
  • spacing elements are disposed in the air gap that separates the internal distributor (2) from the outer casing (3) of the burner (100).
  • This effect can also be achieved by acting on the periodicity of the distributions of the flow openings and of those of the flame openings, by disposing the flame openings on the combustion surface uniformly with a periodic spacing (i.e., a pitch) greater than the spacing with which the flow openings are uniformly distributed at least in the detection portion. If the flame openings and/or the flow openings are disposed according to double-period lattices, it is necessary that in both directions of the lattices the flame openings be disposed with greater spacings (pitches) than the corresponding spacings of the flow openings.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Gas Burners (AREA)

Claims (14)

  1. Vormischbrenner (100), umfassend:
    ein äußeres Gehäuse (3), aufweisend eine Verbrennungsoberfläche (31), die mit Flammenöffnungen (33) versehen und in einer ersten Zone, genannt Flammenzone, befindlich ist,
    einen Verteiler (2), aufweisend eine Verteilungsoberfläche (21), die mit Strömungsöffnungen (23, 26) versehen und in einer zweiten Zone, genannt Verteilungszone, befindlich ist,
    und einen Kopf (1), der mit dem äußeren Gehäuse und dem Verteiler verbunden und mit mindestens einer Öffnung (11) versehen ist, um eine Mischung aus Brennstoff und Oxydationsmittel in den Verteiler (2) einzubringen,
    wobei sich das äußere Gehäuse (3) und der Verteiler (2) des Brenners (100) mindestens in eine erste und eine zweite Richtung erstrecken
    und die Strömungsöffnungen (26) in einem Abschnitt (200) der Verteilungszone, genannt Erkennungsabschnitt, geometrisch derart ausgelegt sind, dass die spezifische Durchflussmenge (q) der Mischung, definiert als Strömung der Mischung durch eine Einheitsoberfläche pro Zeiteinheit, in dem Erkennungsabschnitt (200) größer als im Rest (201, 202) der Verteilungszone ist,
    wobei der Oberflächenbereich des Erkennungsabschnitts (200) kleiner als der Oberflächenbereich der Verteilungszone ist,
    wobei der Verteiler (2) innerhalb des äußeren Gehäuses (3) befindlich ist
    und das äußere Gehäuse (3) und der Verteiler (2) entlang einer dritten Richtung rechtwinkelig zur ersten und zweiten Richtung durch einen Luftspalt (300) getrennt sind, der eine von Null verschiedene Dicke (G) aufweist und durch den die von den Strömungsöffnungen (23, 26) nach außen gerichtete Mischung zu den Flammenöffnungen (33) hin strömt,
    wobei der Brenner Beabstandungselemente umfasst, die in dem Luftspalt angeordnet und vorzugsweise einstückig mit dem Verteiler ausgebildet sind, und wobei der Brenner keine Metallmaschen umfasst,
    dadurch gekennzeichnet, dass
    das äußere Gehäuse und der Verteiler wie koaxiale Zylinder ausgebildet und an einem Ende, an der Position, die dem Kopf des Brenners gegenüberliegt, durch eine Kappe verschlossen sind.
  2. Brenner nach Anspruch 1, wobei die von Null verschiedene Dicke des Luftspalts kleiner als 4 mm und vorzugsweise gleich 0,6 mm ist.
  3. Brenner nach Anspruch 1, wobei die von Null verschiedene Dicke des Luftspalts kleiner als 0,5 mm und vorzugsweise gleich 0,3 mm ist.
  4. Brenner nach einem der vorhergehenden Ansprüche, wobei die Strömungsöffnungen in dem Erkennungsabschnitt geometrisch derart ausgelegt sind, dass das Verhältnis zwischen der Summe der Oberflächen der Strömungsöffnungen und der Gesamtoberfläche des genannten Abschnitts größer ist als das Verhältnis zwischen der Summe der Oberflächen der Öffnungen im Rest der Verteilungszone und der Oberfläche des Rests der Verteilungszone.
  5. Brenner nach einem der vorhergehenden Ansprüche, wobei die Oberfläche einer jeden der Strömungsöffnungen in dem Erkennungsabschnitt größer als die Oberfläche einer jeden der Flammenöffnungen ist.
  6. Brenner nach einem der vorhergehenden Ansprüche, wobei die Strömungsöffnungen kreisförmig sind und einen ersten Durchmesser (D1) aufweisen und die Flammenöffnungen kreisförmig sind und einen zweiten Durchmesser (D2) aufweisen, der kleiner als der erste Durchmesser (D1) ist, wobei der zweite Durchmesser vorzugsweise kleiner oder gleich 1,5 mm ist.
  7. Brenner nach einem der vorhergehenden Ansprüche, wobei die Flammenzone aus einer Vielzahl von Längssektoren besteht, die sich in eine Richtung parallel zur Achse der koaxialen Zylinder erstrecken und in der Umfangsrichtung durch nicht perforierte Sektoren voneinander getrennt sind.
  8. Brenner nach Anspruch 7, wobei die Zahl (N) von nicht perforierten Sektoren größer oder gleich 18 ist und die Breite (x) eines jeden dieser Sektoren in der Umfangsrichtung kleiner oder gleich 1,8 mm ist.
  9. Brenner nach Anspruch 7, wobei die Zahl (N) von nicht perforierten Sektoren kleiner als 18 und größer oder gleich 8 ist und die Breite (x) in Millimetern eines jeden dieser Sektoren in der Umfangsrichtung kleiner oder gleich 1,8·18/N ist, wobei N die Zahl der nicht perforierten Sektoren ist.
  10. Brenner nach Anspruch 7, wobei die Zahl (N) von nicht perforierten Sektoren kleiner als 8 ist und die Breite (x) eines jeden dieser Sektoren in der Umfangsrichtung kleiner als 10 mm ist.
  11. Brenner nach einem der Ansprüche 1 bis 6, wobei die Flammenzone aus einer Vielzahl von Umfangssektoren besteht, die sich parallel zur Richtung des Umfangs der koaxialen Zylinder erstrecken und in der axialen Richtung angrenzend sind.
  12. Brenner nach Anspruch 11, wobei
    die Breite (y) eines jeden der Umfangssektoren in der axialen Richtung kleiner als 5 mm ist, wenn die Zahl (M) von Umfangssektoren größer oder gleich 3 ist;
    die Breite (y) eines jeden der Umfangssektoren in der axialen Richtung kleiner als 30 mm ist, wenn die Zahl (M) von Umfangssektoren kleiner als 3 ist.
  13. Brenner nach einem der vorhergehenden Ansprüche, umfassend eine Erkennungselektrode, die außerhalb der Flammenzone des äußeren Gehäuses an dem Erkennungsabschnitt des Verteilers angeordnet ist.
  14. Heizungskessel, umfassend eine Verbrennungskammer und einen Brenner nach einem der vorhergehenden Ansprüche.
EP24187758.8A 2020-02-05 2021-02-05 Vormischbrenner Active EP4450870B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
IT102020000002209A IT202000002209A1 (it) 2020-02-05 2020-02-05 Bruciatore a premiscelamento
EP21708745.1A EP4100679A1 (de) 2020-02-05 2021-02-05 Vormischbrenner
PCT/IB2021/050947 WO2021156810A1 (en) 2020-02-05 2021-02-05 Premix burner

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EP4450870B1 true EP4450870B1 (de) 2025-12-24

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Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT391197B (de) 1988-04-28 1990-08-27 Vaillant Gmbh Vorrichtung zur ueberwachung des betriebes der von gemischaustrittsoeffnungen durchsetzten brennerplatte eines flaechenbrenners
BE1006201A3 (nl) * 1992-09-16 1994-06-07 Bekaert Sa Nv Gasverbrandingsinrichting.
CH687938A5 (de) * 1992-11-25 1997-03-27 Ygnis Holding Sa Brenner fuer gasfoermige Brennstoffe mit zylinderfoermigem Brennerrohr.
DE69503581T2 (de) * 1994-08-26 1999-01-14 Caradon Ideal Ltd., Hull, North Humberside Gasbrenner
NL1001688C2 (nl) * 1995-11-17 1997-05-21 Furigas Assen Bv Brander met gesegmenteerd branderdek.
DE19912076A1 (de) 1999-03-18 2000-09-21 Kromschroeder Ag G Vormischbrenner für gasförmige Brennstoffe
ITMI20061961A1 (it) 2006-10-13 2008-04-14 Polidoro S P A Distributore differenziato specie per bruciatori premiscelati
ITMO20070167A1 (it) * 2007-05-21 2008-11-22 Worgas Bruciatori Srl Bruciatore modulante
ITVI20110181A1 (it) * 2011-07-05 2013-01-06 Aldo Polidoro Bruciatore di gas combustibile

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WO2021156810A1 (en) 2021-08-12
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