CN112050208A

CN112050208A - Premix gas burner

Info

Publication number: CN112050208A
Application number: CN202010901845.3A
Authority: CN
Inventors: R·博尔; D·霍尔特洛普; R·范祖特费恩特; G·福克斯
Original assignee: Bekaert Combustion Technology BV
Current assignee: Bekaert Combustion Technology BV
Priority date: 2016-09-13
Filing date: 2017-09-11
Publication date: 2020-12-08
Also published as: CN109716023A; EP3513123A1; EP3513123B1; EP3513122B1; KR20190045211A; WO2018050310A1; WO2018050578A1; EP3513122A1; KR102368554B1; CN109716023B; CN109690190A; JP2019526777A; JP2019526776A; CN109690190B

Abstract

A premix gas burner comprising a metal plate structure for mounting the premix gas burner in a heater. The premix gas burner comprises a burner deck. The burner deck comprises a woven wire mesh through which the premixed gas is combusted on the outer surface of the woven wire mesh after the premixed gas has flowed. One or more openings are provided in the metal plate structure. The peripheral edge of the woven wire mesh includes at least one tab. Each tab is inserted through an opening in the metal plate structure.

Description

Premix gas burner

Reference to related applications

The application is a divisional application of invention patent applications with international application numbers of PCT/EP2017/072684, international application dates of 9/11 in 2017, priority dates of 9/13 in 2016, Chinese national phase entering dates of 3/11 in 2019 and Chinese national application numbers of 201780055682.8.

Technical Field

The present invention relates to the field of premix gas burners, and more particularly to a surface stabilized premix gas burner comprising a woven wire mesh as burner deck.

Background

Surface stabilized premix gas burners with woven wire mesh burner decks are known.

US5474443A discloses a premix gas burner with a hemispherical burner deck made of woven wire mesh.

US2005/172915 shows a premix gas burner having a woven wire mesh combustion surface comprising rigid ribs.

EP2876369a1 discloses a gas burner for a boiler. The burner includes a combustion membrane having a diffusion layer in the shape of a three-dimensional shell forming an outer combustion surface having at least one region of double curvature. The combustion surface includes a first portion formed from a perforated metal sheet and a second portion formed from a permeable fibrous or fiberglass based material.

US2014011143A discloses a gas boiler burner comprising a diffuser adapted to diffuse premixed gas in a combustion chamber. The diffuser comprises a diffuser central portion and two diffuser longitudinal peripheral portions. The two diffuser longitudinal peripheral portions are connected together by a diffuser central portion. The diffuser center portion extends longitudinally along a length I greater than zero perpendicular to the direction of fuel gas flow and has a cross-section shaped as a circumferential arc having a uniform radius of curvature r therearound. Each of the diffuser longitudinal perimeter portions is shaped as a portion of a sphere having a radius r.

US2016040905A discloses a burner assembly comprising a diffuser plate and a plurality of burners. The burner is preferably defined as a unitary mesh structure, e.g. a stamped or pressed mesh structure.

Disclosure of Invention

A first aspect of the invention is a premix gas burner. The premix gas burner comprises a metal plate structure for mounting the premix gas burner in the heater. The metal plate structure may comprise or preferably consist of one metal plate; or may comprise more than one metal plate, e.g. two metal plates, preferably connected to each other. The premix gas burner comprises a burner deck. The burner deck comprises, and preferably consists of, a woven wire mesh, the premixed gas being combusted on the outer surface of the woven wire mesh after the premixed gas has flowed through the woven wire mesh. One or more openings are provided in the metal plate structure. The peripheral edge of the woven wire mesh comprises at least one tab; and preferably has a plurality of tabs. Each tab is inserted through an opening in the metal plate structure. Preferably, the one or more tabs comprise or consist of a woven wire mesh.

The woven wire mesh burner deck, which surface stabilizes the premix gas burner, becomes hot while the burner is in use. Woven wire mesh burner decks need to be able to handle: stresses caused by thermal expansion associated with high temperatures when the burner is in use and stresses caused by shrinkage when the burner is not in use. If not, early mechanical failure of the combustor deck may occur. The amount of movement of the woven wire relative to the metal plate structure is possible due to the one or more tabs provided on the periphery of the woven wire burner-the one or more tabs being inserted through openings in the metal plate structure-as the woven wire expands as it heats up or contracts as it cools down. A certain amount of movement of the woven wire mesh relative to the metal sheet structure is possible because the one or more tabs are not mechanically or physically bonded (e.g., by means of welding) to the metal sheet structure. Thus, surprisingly, the premix gas burner of the invention has been shown to be very suitable for withstanding thermal expansion and contraction, thereby extending the life of the premix gas burner.

Preferably the tabs have a generally rectangular shape. Preferably the tabs have a width of between 4-20 mm; more preferably between 6 and 12 mm. Preferably the tabs have a height of between 1-12 mm; more preferably between 3 and 6 mm.

Preferably the tabs have a maximum width of between 4-20 mm; more preferably between 6 and 12 mm. Preferably the tabs have a maximum height of between 3-6 mm.

Preferably, the woven wire mesh has a thickness of between 0.6 and 1.3 mm. By way of example, a 0.9mm thick woven wire mesh may be advantageously used in the present invention.

Preferably, at least one of the tabs is bent such that an included angle of less than 180 ° is provided between the tab inserted through the opening and the portion of the woven wire mesh on the other side of the opening. Preferably, all of the tabs are bent so that an included angle of less than 180 ° is provided between the tab passing through the opening and the portion of the woven wire mesh on the other side of the opening. More preferably, the included angle is less than 150 °, even more preferably less than 120 °. Preferably, the included angle is greater than 30 °, even more preferably greater than 60 °, even more preferably greater than 90 °. The embodiment where at least one tab is bent ensures that the woven wire mesh is better held in the position of application where the burner is used with the burner deck facing downwards; and helps to achieve a longer life of the burner deck and burner.

In a preferred embodiment, the burner deck is provided with a convex shape. This means that when the burner is operating, the flame of the burner is anchored to the convex side of the burner deck. More preferably, the entire surface of the burner deck is provided with a convex shape; this means that the entire surface of the burner deck on the flame anchoring side has a convex shape when the burner is in operation.

In a preferred embodiment, the woven wire mesh does not include ribs nor ridges.

In a preferred embodiment, the woven wire mesh comprises ribs and/or protuberances.

In a preferred embodiment the burner deck has a rectangular shape around its circumference, the two short sides of the rectangle having been rounded. More preferably, the short sides of the rectangle are continuously rounded.

In embodiments where the circumference of the burner deck has a rectangular shape, the two short sides of which have been-preferably continuously-rounded, the tabs are preferably provided only along the two long sides of the rectangular shape of the circumference of the burner deck. This means that no tabs are provided along the, possibly continuous, rounded short sides. The burner according to this embodiment is even more suitable for long life use, since the absence of tabs along the short sides allows for a better thermal expansion of the woven wire mesh in its length direction.

In a preferred embodiment, the metal plate structure comprises a groove. The width of the groove is greater than the thickness of the woven wire mesh. At least part of, preferably the entire, peripheral edge of the woven wire mesh is positioned in the groove. Preferably, at least part of the openings, and preferably all of the openings, are provided in the groove (and preferably at the bottom of the groove). Such embodiments synergistically help to provide a combustor with a long lifetime. Since the width of the groove is greater than the thickness of the woven wire mesh, a certain amount of movement of the woven wire mesh relative to the metal sheet structure is provided. Furthermore, an additional benefit of such an embodiment is that there is less risk of flame tempering occurring via the edges of the woven wire mesh.

Preferably, the depth of the groove is at least 1mm, more preferably at least 2 mm.

Preferably, the width of the groove is at least 0.1mm greater than the thickness of the woven wire mesh. More preferably, the width of the groove is at least 0.3mm greater than the thickness of the woven wire mesh. Preferably, the width of the grooves is less than 0.8mm greater than the thickness of the woven wire mesh. Such embodiments provide a combustor with a long life; since such a burner is very suitable for dealing with thermal stresses on the deck of a woven wire mesh burner when the burner is in use.

Preferably, the depth of the groove is at least three times the difference between the width of the groove and the thickness of the woven wire mesh. These embodiments provide a combustor having a long life; as such burners are even more suitable for dealing with thermal stresses on the deck of woven wire mesh burners when the burner is in use.

In an embodiment where the metal plate structure comprises a groove and the circumference of the burner deck has a rectangular shape, but the rectangle has two short sides in the shape of a rounded corner, preferably continuously rounded corner, the width of the groove is preferably larger in the two, preferably continuously rounded corner, short sides than in the two long sides of the rectangular shape along the circumference of the burner deck. The burner according to this embodiment is even more suitable for long life use, since the absence of tabs along the short sides in combination with the wider grooves at the short sides allows for a better thermal expansion of the woven wire mesh in its length direction.

In a preferred embodiment where the metal structure comprises grooves distributed along the entire circumference of the burner deck, a plurality of slits are provided in the plate structure at the bottom of the grooves. The peripheral edge of the woven wire mesh comprises a plurality of tabs distributed along the entire peripheral edge of the woven wire mesh; and each tab is inserted through the slit. Such an embodiment provides further improvements in combustor life.

Preferably the premix gas burner comprises perforated plate segments through which the premix gas flows before flowing through the woven wire mesh. Perforated plate segments are provided to distribute the premix gas more evenly over the surface of the burner deck; and thus, contribute to the extension of the life of the burner. More preferably, all the areas of the perforated plate segments provided with perforations are provided at a distance of at least 1mm from the woven wire mesh; and preferably at a distance of less than 3 mm. Such an embodiment facilitates the production of a burner with a long lifetime.

In a preferred burner comprising perforated plate segments, the premix gas flows through the perforated plate segments before the premix gas flows through the woven wire mesh, the metal plate structure comprising a first metal plate for mounting the burner in the heater and a second metal plate comprising perforated plate segments. In embodiments where the metal plate structure comprises a groove, preferably one side of the groove is provided by the first metal plate; and the other side of the groove is provided by a second metal plate.

In a preferred burner comprising perforated plate segments, the premix gas flows through the perforated plate segments before the premix gas flows through the woven wire mesh, the metal plate structure comprising a metal plate. The metal plate comprises a portion for mounting the burner in the heater and a perforated plate segment. In embodiments where the metal plate structure comprises a groove, preferably the groove is provided by a shaped metal plate; for example by deep drawing of sheet metal.

A second aspect of the invention is a condensing boiler comprising a premix gas burner according to any of the embodiments of the first aspect of the invention. Preferably, the condensing boiler comprises a cast aluminium heat exchanger.

Drawings

Fig. 1 and 2 show a premix gas burner according to the invention.

Fig. 3, 4 and 5 show cross-sections of a premix gas burner according to the invention.

Figure 6 shows the angle between the tab inserted through the opening and the portion of the woven wire mesh on the other side of the opening.

Detailed Description

Fig. 1 and 2 show a premix gas burner according to a first aspect of the invention. Fig. 1 shows the burner on the deck side of the burner where combustion takes place, while fig. 2 shows the burner from the side where premix gas is supplied. The premix gas burner comprises a metal plate structure 105 for mounting the premix gas burner in the heater, a burner deck 110 and a groove 115 in the metal plate structure 105 (not visible in fig. 1, the groove can be seen from the bottom in fig. 2). The burner deck 110 consists of a woven wire mesh through which the premixed gas is combusted on the outer surface of the woven wire mesh after the premixed gas has flowed. In this example, the burner deck is provided in a convex shape across the entire surface of the burner deck. In an exemplary burner, the woven wire mesh does not include ribs or ridges. The periphery of the burner deck of the exemplary burner has a rectangular shape, the two short sides of which have been rounded continuously; however, other circumferential shapes of the burner deck are also possible.

The width of the groove 105 is greater than the thickness of the woven wire mesh. A plurality of openings 120 are provided at the bottom of the groove 115. The opening may, for example, take the form of a slit at the bottom of the recess. The peripheral edge of the woven wire mesh is positioned in the groove 115. The peripheral edge of the woven wire mesh includes a plurality of tabs 125; each tab is inserted through an opening in the bottom of the groove. In this example, the tabs are provided only along the two long sides of the rectangular shape of the circumference of the burner deck. In this example, the width of the groove is greater in the two consecutive rounded short sides than in the two long sides of the rectangular shape along the circumference of the burner deck.

In the preferred burner, the tabs are bent (not shown in fig. 2, but illustrated in fig. 6) relative to the surface of the burner deck, so that the woven wire mesh is better retained in the premix gas burner.

Fig. 2 shows the burner from the side where the premix gas is supplied, as can be seen in fig. 2, the exemplary burner comprises a perforated plate 130 through which the premix gas flows 130 before flowing through the woven wire mesh.

Fig. 3, 4 and 5 show cross-sections of a burner according to three different implementations of the first aspect of the invention.

FIG. 3 illustrates a cross-section 300 of the exemplary combustor shown in FIGS. 1 and 2 along plane A1-A1 of FIG. 1. The metal plate structure 305 comprises a metal plate comprising a portion 307 for mounting the burner in the heater and a perforated plate segment 330. The metal plate structure (one metal plate) 305 is formed by punching and deep drawing. The metal plate 305 includes a recess 315 having an opening 320. The peripheral edge of the woven wire mesh 310 is positioned in the groove 315. Tabs 325 at the peripheral edge of the woven wire mesh 310 are inserted through openings 320 at the bottom of the groove 315 (the cross-section shown in fig. 3 passes through the tabs on both sides of the burner). Preferably, all areas of the perforated plate segment 330 provided with perforations are provided at a distance of at least 1mm from the woven wire mesh 310; and preferably at a distance of less than 3 mm. As an example, the depth D of the groove was 2mm, the width W of the groove was 1.5, and the thickness of the woven wire mesh was 0.9 mm. Preferably, the tab is bent (not shown in fig. 3) -more preferably towards the inside of the burner-so that the tab inserted through the opening forms an angle of less than 180-preferably less than 150-with the portion of the woven wire on the other side of the opening.

Fig. 4 shows a cross-section 400 of a burner according to an alternative embodiment of the invention. The metal plate structure 405 includes a metal plate. The metal plate comprises a portion 407 for mounting the burner in the heater and a perforated plate segment 430. The premix gas flows through the perforations of perforated plate segments 430 before the premix gas flows through woven wire mesh burner deck 410 to be combusted on the other side of woven wire mesh burner deck 410. The metal plate structure (one metal plate) 405 is formed by stamping and deep drawing. The metal plate 405 includes openings 420 but no recesses. Tabs 425 at the peripheral edge of the woven wire mesh 410 are inserted through the openings (the cross-section shown in fig. 4 passes through the tabs on both sides of the burner). Preferably, all areas of the perforated plate segment 430 provided with perforations are provided at a distance of at least 1mm from the woven wire mesh 410; and preferably at a distance of less than 3 mm. Preferably, the tab is bent (not shown in fig. 4) -more preferably towards the inside of the burner-so that an angle of less than 180-preferably less than 150-is formed between the tab inserted through the opening and the portion of the woven wire on the other side of the opening.

Fig. 5 shows a cross-section 500 of a burner according to an alternative embodiment of the invention. The metal plate structure 505 comprises a first metal plate 507 for mounting the burner in the heater and a second metal plate 530 comprising perforated plate segments. The premix gas flows through the perforated plate segments before it flows through the woven wire mesh burner deck 510 to be combusted on the other side of the woven wire mesh burner deck 510. A groove 515 is provided in the metal plate structure 505. One side of the groove 515 is provided by the first metal plate 507; the other side of the groove is provided by a second metal plate 510. The peripheral edge of the woven wire mesh 510 is positioned in the groove 515. Tabs 525 at the peripheral edge of the woven wire mesh 510 are inserted through openings 520 at the bottom of the groove 515 (the cross-section shown in fig. 5 passes through the tabs on both sides of the burner). As an example, the depth of the groove is 2mm, the width of the groove is 1.5mm, and the thickness of the woven wire mesh is 0.9 mm. Preferably, the tab is bent (not shown in fig. 5) -more preferably towards the inside of the burner-so that an angle of less than 180-preferably less than 150-is formed between the tab inserted through the opening and the portion of the woven wire on the other side of the opening.

Figure 6 illustrates the angle between the tab inserted through the opening and the portion of the woven wire mesh on the other side of the opening. Fig. 6 shows a portion of the burner of the present invention. Fig. 6 shows a portion of a metal plate structure 605 for mounting a burner, a portion of a perforated metal plate 630, a groove 615, a portion of a woven wire mesh 610, and a tab 625 inserted through an opening at the bottom of the groove. Fig. 6 illustrates how the tab is preferably bent so that an angle α (α) is formed between the tab 615 inserted through the opening and the portion of the woven wire mesh 610 on the other side of the opening. Preferably, the included angle is less than 150 °. In this example, the tab is bent toward the inside of the burner.

Claims

1. A premix gas burner comprising:

a metal plate structure for mounting the premix gas burner in a heater; and

a burner deck, wherein the burner deck comprises a woven wire mesh over which a premix gas is combusted on an outer surface of the woven wire mesh after the premix gas has flowed;

wherein one or more openings are provided in the metal plate structure;

wherein said woven wire mesh includes a peripheral edge;

wherein the peripheral edge of the woven wire mesh comprises at least one tab;

wherein each tab is inserted through an opening in the metal plate structure,

wherein the peripheral edge has a rectangular shape, the two short sides of which have been rounded, wherein tabs are provided only along the two long sides of the rectangular shape.

2. The premix gas burner of claim 1, wherein at least one tab is bent such that an included angle of less than 180 ° is provided between the tab inserted through the opening and a portion of the woven wire mesh on the other side of the opening.

3. The premix gas burner of claim 2, wherein said included angle is less than 150 °.

4. The premix gas burner as in any of the preceding claims, wherein the burner deck is provided with a convex shape.

5. The premix gas burner as in any of claims 1-3, wherein said two short sides have been rounded continuously.

6. The premix gas burner as in any of claims 1 to 3,

wherein the metal plate structure comprises a groove;

wherein the width of the groove is greater than the thickness of the woven wire mesh;

wherein at least a portion of the peripheral edge of the woven wire mesh is positioned in the groove; and is

Wherein at least a portion of the opening is disposed in the groove.

7. The premix gas burner of claim 6, wherein the entire peripheral edge of the woven wire mesh is positioned in the groove.

8. The premix gas burner of claim 6, wherein the width of the groove is at least 0.1mm greater than the thickness of the woven wire mesh.

9. The premix gas burner of claim 6; wherein the width of the groove is greater in the two short sides of the rounded shape than the two long sides of the rectangular shape along the circumference of the burner deck.

10. The premix gas burner of claim 6, wherein the burner comprises perforated plate segments through which the premix gas flows before flowing through the woven wire mesh.

11. The premix gas burner as in claim 10, wherein all areas of said perforated plate segments provided with perforations are provided at a distance of at least 1mm from said woven wire mesh.

12. The premix gas burner of claim 10, wherein the metal plate structure comprises: a first metal plate for mounting the burner in a heater; and a second metal plate comprising said perforated plate segment.

13. The premix gas burner of claim 12, wherein one side of said groove is provided by said first metal plate; and the other side of the groove is provided by the second metal plate.

14. The premix gas burner of claim 10, wherein the metal plate structure comprises a metal plate; wherein the metal plate comprises a portion for mounting the burner in a heater, and the perforated plate segment.

15. The premix gas burner of claim 14, wherein the grooves are provided by shaping the metal plate.