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(11) | EP 1 036 983 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
Tubular burner Rohrbrenner Brûleur tubulaire |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] Tubular burners consist of a tubular shaped body into which a mixture of air and fuel, for example gaseous fuel, is introduced. The body is provided with openings through which said mixture is made to flow out and then burned.
[0002] The mixture of air and fuel can be introduced into a tubular burner in various ways. Such a burner is shown for example in EP 0 844 435 A.
[0003] In the so-called naturally aerated burners, the body of the burner is provided internally with a Venturi tube into which the fuel is introduced under pressure by way of an injector nozzle, resulting in the intake of air from outside due to the so-called Venturi effect and formation of the mixture of air and gaseous fuel.
[0004] In the so-called pre-mixed burners, said mixture is introduced into the body of the burner by means of a fan or a compressor. In the so-called mixed or fan-assisted burners, a mixture of air and fuel is introduced into the burner, by way of a fan or a compressor, under pressure or by suction, supercharging a Venturi tube housed in the body of the burner.
[0005] The body of the tubular burners can be obtained from a piece of metal sheet folded into the shape of a tube, of which the edges parallel to the axis of the tube are joined together by for example welding or seaming. In burners produced in this fashion, the entire body of the burner must be made of metal resistant to the high temperatures created by combustion of the mixture of air and gaseous fuel, even though only the portion of the burner body having the openings for outflow of the mixture of air and fuel is subjected to said high temperatures. Furthermore, the thermal expansions to which the body of the burner is subjected during operation differ from zone to zone due to the different temperatures reached by the various zones of the burner body due to the distribution of the openings for outflow of the mixture of fuel and air to be burned. This distribution is not generally uniform, since there are zones of the body of the burner entirely without openings and zones with various densities of said openings. The different thermal expansions to which the various zones of the body of the burner are subjected give rise to mechanical stresses which reduce the lifetime of the burner.
[0006] Another known technique is to produce the body of a tubular burner with two shells of folded metal sheet, each of semi-tubular shape, joining together said two shells by welding, in such a way as to form a tubular body, along their edges parallel to the axis of said tubular body.
[0007] With this form of construction, it is possible to use different materials for the two shells constituting the body of the burner: for example, a material with high temperature resistance for a first shell in which for example the openings for the outflow of the air and fuel mixture are made and a less high quality and hence less expensive material for the other shell, for example without said openings, which is subjected to much lower temperatures than the first shell.
[0008] However, the joining of the two shells by welding creates some problems since the different thermal expansions of the two shells, due to the different temperatures to which they are subjected, give rise to deformations in the body of the burner during operation, with consequent mechanical stresses which limit the lifetime of the burner. Furthermore, the joining of the two shells by welding requires a continuous type procedure, in other words it is not possible to produce single or a limited number of burners at low cost. Finally, welding technology requires costly expedients to prevent the occurrence of detrimental effects, such as local strain hardening of the welded parts or welding defects.
[0010] The present invention envisages a burner which can be fed with a mixture of air and fuel provided with a tubular body, with openings for the outflow of said mixture of air and fuel and having a longitudinal axis, said tubular body comprising at least a first body portion and at least a second body portion, said first portion and said second portion being joined together along respective edges parallel to said longitudinal axis, characterised by the fact that said first portion and said second portion are joined together by seaming of said edges.
[0011] The present invention permits simple and cheap production of a tubular burner consisting of portions made of different materials, for example a material with high temperature resistance for the portions subjected to higher temperatures and a less temperature resistant, and hence less costly, material for the portions subjected to lower temperatures, with a considerable reduction in costs. Furthermore the burner body portions can be joined by seaming in such a way as to permit reciprocal sliding movement of each portion relative to adjacent portions in a direction parallel to the axis of the burner in order to compensate for the different thermal expansions to which said portions are subjected, thereby avoiding deformations of the burner body and consequent mechanical stresses and significantly improving the lifetime of the burner.
[0012] Further advantages and characteristics of the present invention will become evident from the following description, provided purely as a non-limiting example, with reference to the attached drawings in which:
figure 1 is a cross-section of a burner according to the invention, of which the body consists of two semi-tubular portions joined together by seaming;
figure 2 is a cross-section of a tubular burner according to the invention, of which the body consists of four portions joined together by seaming;
figure 3 is an enlarged detail of the seamed join of two adjacent portions of the body of the burner shown in figures 1 or 2;
figure 4 is a perspective view of the burner of figure 1;
figure 5 is a side view of the burner of figure 1 showing, not to scale, the reciprocal sliding movement of the two semi-tubular portions of the burner body due to different thermal expansions during operation of the burner;
figure 6 is a top view of the burner of figure 2;
figure 7 is a view like the one shown in figure 6 showing, not to scale, the reciprocal sliding movement of two adjacent portions of the burner body due to different thermal expansions during operation of the burner.
[0013] Figure 1 shows a tubular burner according to the invention comprising a tubular body 1 with a longitudinal axis A, consisting of a first semi-tubular shaped body portion 2 and a second body portion 3, also of semi-tubular shape. On one of said semi-tubular portions, for example the first semi-tubular portion 2, there are made openings 4 for the outflow and subsequent combustion of a mixture of air and gaseous fuel which is introduced into the tubular body 1. The first semi-tubular portion 2 and the second semi-tubular portion 3 are joined together by seaming along their respective edges 5 and 6, which are substantially parallel to said longitudinal axis A. The seaming is carried out in such a way that the edges 5 and 6, in the seaming zone, constitute a seal preventing said mixture of air and gaseous fuel from escaping. Furthermore, the seaming may be carried out in such a way that the first semi-tubular portion 2 and the second semi-tubular portion 3 are able to slide relative to each other in a direction parallel to the axis A of the burner body 1. This makes it possible to compensate for the different thermal expansions to which the first semi-tubular portion 2 and the second semi-tubular portion 3 are subjected due to the different temperatures to which they are subjected during operation of the burner. The first semi-tubular portion 2, on which the openings 4 are made, is in fact subjected to much higher temperatures than the second semi-tubular portion 3 due to combustion of the mixture of air and gaseous fuel, which occurs in the proximity of the external surface zone of the semi-tubular portion 2 on which the openings 4 are made. Reciprocal sliding movement between the two semi-tubular portions 2 and 3 of the burner body 1 due to different thermal expansions of said portions is marked by S in figure 5.
[0014] By compensating for the different thermal expansions it is possible to avoid permanent deformations and mechanical stresses in the tubular body 1 of the burner during its operation, thereby significantly increasing the lifetime of the burner.
[0015] The two semi-tubular portions 2 and 3 may also be made of different materials, using a high quality material with high temperature resistance for the first semi-tubular portion 2, which is subjected to very high temperatures during operation of the burner, and a less high quality material, with lower temperature resistance, for the second semi-tubular portion 3, which is subjected to considerably lower temperatures. This permits a significant reduction in the production costs of the burner.
[0016] Figures 2, 6 and 7 show a second version of a burner according to the invention comprising a tubular body 1 consisting of four portions, respectively a first body portion 7, a second body portion 8, a third body portion 9 and a fourth body portion 10, all of which are arch-shaped.
[0017] Each of said body portions is joined to the adjacent portions by seaming along the respective longitudinal edges 12, 13, 14, 15, which are substantially parallel to the longitudinal axis A of the burner body 1.
[0018] On the first burner portion 7 there are made first openings 16 for the outflow and subsequent combustion of a mixture of air and fuel which is introduced into the tubular body 1. On the second burner portion 8 there are made second openings 17 for the outflow and subsequent combustion of said mixture of air and fuel. The distribution and/or total area of said second openings 16 is different from the distribution and/or total area of said second openings 17.
[0019] Analogously to the burner version shown in figures 1 and 4, the seamed joins are made in such a way that the longitudinal edges 12, 13, 14, 15 in the seaming zones constitute a seal preventing said mixture of air and fuel from escaping. Furthermore, the seamed joins can be made in such a way that each burner portion 7, 8, 9, 10 is able to slide relative to the adjacent burner portions, in a direction parallel to the A axis of the burner body 1. The seamed joins of the burner portions make it possible to compensate for the different thermal expansions that said portions undergo due to the different temperatures to which they are subjected during operation of the burner. Said different temperatures depend on whether or not openings 16, 17 for the outflow of said mixture of gaseous fuel and air are present, and on the number, distribution and total area of said openings on burner portions 7, 8, 9, 10. By compensating for the different thermal expansions, it is possible to avoid permanent deformations and mechanical stresses in the tubular body 1 of the burner during its operation, thereby significantly increasing the lifetime of the burner. Reciprocal sliding movement between the two adjacent portions 7 and 8 of the burner body 1 due to the different thermal expansions of said portions is marked by S in figure 7.
[0020] Furthermore, it is possible to make burner body portions 7, 8, 9, 10 from different materials according to their respective operating temperatures, thereby significantly reducing production costs of the burner.
[0021] If the burner is provided at both ends with a flange 18 for mounting the burner inside a heating appliance, at least one flange 18 is made in such a way as to permit reciprocal axial sliding movement of burner body portions 2, 3; 7, 8, 9, 10. For example the burner portions intended for operation at the highest operating temperatures are fixed with a clearance to said at least one flange 18, with labyrinth seals (not shown) to prevent the mixture of gaseous fuel and air from escaping from said clearances.
1. A burner which can be fed with a mixture of air and fuel, provided with a tubular
body (1) with openings (4; 16, 17) for the outflow of said mixture of air and fuel
and having a longitudinal axis (A), said tubular body (1) comprising burner body portions
(2, 3; 7, 8, 9, 10) joined together along respective edges (5, 6; 12, 13, 14, 15)
substantially parallel to said longitudinal axis (A), characterised by the fact that said portions (2, 3; 7, 8, 9, 10) are joined together by seaming of
said edges (5, 6; 12, 13, 14, 15).
2. A burner as defined in claim 1, characterised by the fact that said seaming is carried out in such a way as to permit a sliding movement
(S) of each of said portions (2, 3; 7, 8, 9, 10) relative to an adjacent portion,
in a direction substantially parallel to said longitudinal axis (A).
3. A burner as defined in claims 1 or 2, characterised by the fact that said seaming is carried out in such a way as to constitute a seal preventing
said mixture of air and fuel from escaping from inside the body (1) of the burner.
4. A burner as defined in any of the previous claims, characterised by the fact that at least one of said burner body portions (2, 3; 7, 8, 9, 10) is made
of a different material from the other burner body portions.
5. A burner as defined in any of the previous claims, characterised by the fact that said openings (16, 17) are made on at least a first portion (7) and
a second portion (8) of said burner body portions (2, 3; 7, 8, 9, 10).
6. A burner as defined in claim 5, characterised by the fact that the distribution of the openings (16) on said first portion (7) is
different from the distribution of the openings (17) on said second portion.
7. A burner as defined in claims 5 or 6, characterised by the fact that the total area of the openings (16) on said first portion (7) is different
from the total area of the openings (17) on said second portion (8).
8. A burner as defined in one of the previous claims, characterised by the fact that said tubular body (1) is provided at both ends with flanges (18), at
least one of said flanges (18) being joined to said burner body portions (2, 3; 7,
8, 9, 10) in such a way as to permit a sliding movement (S) of each of said portions
(2, 3; 7, 8, 9, 10) relative to an adjacent portion, in a direction substantially
parallel to said longitudinal axis (A).
9. A burner as defined in claim 8, characterised by the fact that said at least one flange (18) is joined rigidly to burner body portions
(2, 3; 7, 8, 9, 10) subjected to lower operating temperatures and is joined with a
clearance to burner body portions (2, 3; 7, 8, 9, 10) subjected to higher operating
temperatures.
10. A burner as defined in claim 9, characterised by the fact that between said at least one flange (18) and said burner body portions
(2, 3; 7, 8, 9, 10) subjected to higher operating temperatures there is envisaged
a sealing means to prevent said mixture of air and gaseous fuel from escaping.
1. Mit einem Gemisch aus Luft und einem Brennstoff speisbarer Brenner, mit einem rohrförmigen
Körper (1) mit Öffnungen (4; 16, 17) zum Ausströmen des Gemisches aus Luft und Brennstoff,
und mit einer Längsachse (A), wobei der rohrförmige Körper (1) Brennerkörperbereiche
(2, 3; 7, 8, 9, 10) aufweist, die miteinander entlang von entsprechenden Kanten (5,
6; 12, 13, 14, 15) verbunden sind, die im wesentlichen parallel zu der Längsachse
(A) verlaufen, dadurch gekennzeichnet, dass die Bereiche (2, 3; 7, 8, 9, 10) durch Falzen der Kanten (5, 6; 12, 13, 14, 15) miteinander
verbunden sind.
2. Brenner nach Anspruch 1, dadurch gekennzeichnet, dass das Falzen derart ausgeführt wird, dass eine Gleitbewegung (S) der Bereiche (2, 3;
7, 8, 9, 10) relativ zu dem jeweils angrenzenden Bereich in einer Richtung im Wesentlichen
parallel zu der Längsachse (A) möglich ist.
3. Brenner nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass das Falzen derart ausgeführt wird, dass eine Abdichtung bewirkt wird, die ein Ausströmen
des Gemisches aus Luft und Brennstoff aus dem Innenraum des Körpers (1) des Brenners
verhindert.
4. Brenner nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass mindestens einer der Brennerkörperbereiche (2, 3; 7, 8, 9, 10) aus einem anderen
Werkstoff als die anderen Brennerkörperbereiche hergestellt ist.
5. Brenner nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass die Öffnungen (16, 17) auf mindestens einem ersten Bereich (7) und einem zweiten
Bereich (8) der Brennerkörperbereiche (2, 3; 7, 8, 9, 10) ausgebildet sind.
6. Brenner nach Anspruch 5, dadurch gekennzeichnet, dass die Verteilung der Öffnungen (16) auf dem ersten Bereich (7) verschieden von der
Verteilung der Öffnungen (17) auf dem zweiten Bereich ist.
7. Brenner nach Anspruch 5 oder 6, dadurch gekennzeichnet, dass die Gesamtoberfläche der Öffnungen (16) auf dem ersten Bereich (7) verschieden von
der Gesamtoberfläche der Öffnungen (17) auf dem zweiten Bereich (8) ist.
8. Brenner nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, dass der rohrförmige Körper (1) an beiden Enden mit Flanschen (18) versehen ist, wobei
mindestens einer der Flansche (18) mit den Brennerkörperbereichen (2, 3; 7, 8, 9,
10) derart verbunden ist, dass eine Gleitbewegung (S) der Bereiche (2, 3; 7, 8, 9,
10) relativ zu dem jeweils angrenzenden Bereich in einer Richtung im Wesentlichen
parallel zu der Längsachse (A) möglich ist.
9. Brenner nach Anspruch 8, dadurch gekennzeichnet, dass der mindestens eine Flansch (18) starr mit Brennerkörperbereichen (2, 3; 7, 8, 9,
10) verbunden ist, die niedrigeren Betriebstemperaturen ausgesetzt sind, und über
einen Freiraum mit Brennerkörperbereichen (2, 3; 7, 8, 9, 10) verbunden ist, die höheren
Betriebstemperaturen ausgesetzt sind.
10. Brenner nach Anspruch 9, dadurch gekennzeichnet, dass zwischen dem mindestens einen Flansch (18) und den Brennerkörperbereichen (2, 3;
7, 8, 9, 10), die höheren Betriebstemperaturen ausgesetzt sind, ein Dichtungsmittel
vorgesehen ist, um ein Ausströmen des Gemisches aus Luft und gasförmigem Brennstoff
zu verhindern.
1. Brûleur qui peut être alimenté avec un mélange d'air et de combustible, pourvu d'un
corps tubulaire (1) avec des ouvertures (4 ; 16, 17) pour l'écoulement dudit mélange
d'air et de combustible et ayant un axe longitudinal (A), ledit corps tubulaire (1)
comprenant des portions (2, 3 ; 7, 8, 9, 10) de corps de brûleur réunies entre elles
le long de bords respectifs (5, 6 ; 12, 13, 14, 15) sensiblement parallèles audit
axe longitudinal (A), caractérisé par le fait que lesdites portions (2, 3 ; 7, 8, 9, 10) sont réunies entre elles par agrafage desdits
bords (5, 6 ; 12, 13, 14, 15).
2. Brûleur selon la revendication 1, caractérisé par le fait que ledit agrafage est réalisé d'une telle manière qu'il permette un mouvement glissant
(S) de chacune desdites portions (2, 3 ; 7, 8, 9, 10) par rapport à une portion adjacente,
dans une direction essentiellement parallèle audit axe longitudinal (A).
3. Brûleur selon les revendications 1 ou 2, caractérisé par le fait que ledit agrafage est réalisé de manière à constituer un joint étanche empêchant ledit
mélange d'air et de combustible de s'échapper de l'intérieur du corps (1) du brûleur.
4. Brûleur selon l'une quelconque des revendications précédentes, caractérisé par le fait qu'au moins une desdites portions (2, 3 ; 7, 8, 9, 10) du corps du brûleur est faite d'un
matériau différent des autres portions du corps du brûleur.
5. Brûleur selon l'une quelconque des revendications précédentes, caractérisé par le fait que lesdites ouvertures (16, 17) sont ménagées sur au moins une première portion (7)
et une seconde portion (8) desdites portions (2, 3 ; 7, 8, 9, 10) du corps du brûleur.
6. Brûleur selon la revendication 5, caractérisé par le fait que la distribution des ouvertures (16) sur ladite première portion (7) est différente
de la distribution des ouvertures (17) sur ladite seconde portion.
7. Brûleur selon les revendications 5 ou 6, caractérisé par le fait que l'aire totale des ouvertures (16) sur ladite première portion (7) est différente
de l'aire totale des ouvertures (17) sur ladite seconde portion (8).
8. Brûleur selon l'une quelconque des revendications précédentes, caractérisé par le fait que ledit corps tubulaire (1) est muni, sur des deux extrémités, de brides (18), au moins
l'une desdites brides (18) étant réunie auxdites portions (2, 3 ; 7, 8, 9, 10) du
corps du brûleur de manière à permettre un mouvement coulissant (S) de chacune desdites
portions (2, 3 ; 7, 8, 9, 10) par rapport à une portion adjacente, dans une direction
sensiblement parallèle audit axe longitudinal (A).
9. Brûleur selon la revendication 8, caractérisé par le fait que ladite au moins une bride (18) est réunie de manière rigide aux portions (2, 3 ;
7, 8, 9, 10) du corps du brûleur soumises à des températures de fonctionnement inférieures
et est réuni avec du jeu aux portions (2, 3 ; 7, 8, 9, 10) du corps du brûleur soumises
à des températures de fonctionnement plus élevées.
10. Brûleur selon la revendication 9, caractérisé par le fait qu'entre ladite au moins une bride (18) et lesdites portions (2, 3 ; 7, 8, 9, 10) du
corps du brûleur soumises à des températures de fonctionnement supérieures, il est
envisagé un moyen d'étanchéité pour empêeher ledit mélange d'air et de combustible
gazeux de s'échapper.