EP3336427A1

EP3336427A1 - Gas burner

Info

Publication number: EP3336427A1
Application number: EP16382614.2A
Authority: EP
Inventors: Ricardo Marin Marin; Luis Diaz Lecumberri; Iker URRESTI UGARTEBURU
Original assignee: Ikerlan S Coop
Current assignee: Ikerlan S Coop
Priority date: 2016-12-16
Filing date: 2016-12-16
Publication date: 2018-06-20
Anticipated expiration: 2036-12-16
Also published as: ES2747398T3; EP3336427B1

Abstract

Gas burner comprising a structure (1A) with gas distribution means configured for directing gas to a mixing area and air distribution means configured for directing air to said mixing area. The gas and air distribution means are communicated with a gas inlet conduit (2) and an air inlet conduit (3), respectively. The gas distribution means comprise a plurality of main conduits (4b) providing a mixing point at the outlet of each main conduit (4b). The air distribution means comprise a chamber (5) communicated with the air inlet conduit (3), and a distributor plate (5') arranged in the mixing area comprising a plurality of passage openings, each passage opening being configured for directing air to at least one mixing point.

Description

TECHNICAL FIELD

The present invention relates to gas burners, and more specifically to burners for gas boilers.

PRIOR ART

A burner is a device for burning gas, liquid and solid fuel (for example, pellets) such that heat is generated by means of flame. A burner is usually associated with a boiler or a generator for heating water.
The most widely used burners are gas burners in which said gas, usually mixed with air, burns when a spark is generated. Burners of this type in which gas and air are mixed before ignition occurs are called premix burners. However, burners called diffusion burners in which combustible gas and oxygen are not mixed beforehand, but rather mixed where ignition occurs are also known.
In this sense, patent document JP2006056743A discloses a gas burner comprising a structure in which gas distribution means direct a combustible gas, such as hydrogen, to a mixing area, and oxygen distribution means direct oxygen to the mixing area. The gas distribution means comprise an open chamber arranged inside said structure and the oxygen distribution means comprise a plurality of conduits arranged inside said open chamber such that the combustible gas flows between the oxygen conduits. The gas distribution means are communicated with a combustible gas inlet conduit and the oxygen distribution means with an oxygen inlet conduit.

DISCLOSURE OF THE INVENTION

The object of the invention is to provide a gas burner, as defined in the claims.
The gas burner according to the invention comprises a structure comprising gas distribution means which are configured for directing combustible gas to a mixing area, and air distribution means configured for directing air to said mixing area. The gas distribution means are communicated with a combustible gas inlet conduit and the air distribution means are communicated with an air inlet conduit.
The gas distribution means comprise a plurality of main conduits communicated with the gas inlet conduit and configured for transporting combustible gas to the mixing area providing a mixing point at the outlet of each main conduit.
The air distribution means comprise an air chamber communicated with the air inlet conduit in which at least part of each main conduit is housed.
The air distribution means also comprise a distributor plate arranged in the mixing area comprising a plurality of passage openings, each passage opening being configured for directing air to at least one mixing point.
The gas burner of the invention allows efficiently directing the required air to the combustible gas so that it burns quickly and effectively when the ignition means, for example, a spark generator, are activated.
Focusing the passage of air through the passage openings of the distributor plate assures, on one hand, that the amount of air required for combustible gas ignition to occur reaches each mixing point, and on the other hand, that the same amount of air reaches all the mixing points, leading to the flames that burn at the outlet of the main conduits being similar, so a homogenous distribution of flames throughout the burner is achieved.
These and other advantages and features of the invention will become evident in view of the drawings and the detailed description of the invention.

DESCRIPTION OF THE DRAWINGS

Figure 1 shows a perspective view of the gas burner according to an embodiment of the invention.
Figure 2 shows a sectioned perspective view of the gas burner of Figure 1.
Figure 3 shows a sectioned front view of the gas burner of Figure 1.
Figure 4 shows a perspective view of a first detail of the gas burner of Figure 1.
Figure 5 shows a second detail of the gas burner of Figure 1.

DETAILED DISCLOSURE OF THE INVENTION

Figure 1 shows an embodiment of a gas burner 1 according to the invention. Said burner 1 comprises a structure 1A comprising gas distribution means which are configured for directing combustible gas to a mixing area 7, and air distribution means configured for directing air to said mixing area 7. The gas distribution means are communicated with a combustible gas inlet conduit 2 and the air distribution means are communicated with an air inlet conduit 3.
The gas distribution means comprise a plurality of main conduits 4b, as shown in Figures 2 to 5, configured for transporting combustible gas to the mixing area 7 providing a mixing point at the outlet of each main conduit 4b.
The air distribution means comprise an air chamber 5 which is communicated with the air inlet conduit 3, said main conduits 4b being at least partially housed in said air chamber 5.
The air distribution means also comprise a distributor plate 5' arranged in the mixing area 7 comprising a plurality of passage openings 5a, each passage opening 5a being configured for directing air to at least one mixing point.
With the gas burner of the invention, the required air is efficiently directed to the combustible gas so that it burns quickly and effectively when ignition means, not shown in the drawings, for example a spark generator, are activated.
Focusing the passage of air through the passage openings 5a of the distributor plate 5 assures, on one hand, that the amount of air required for combustible gas ignition to occur reaches each mixing point, and on the other hand, that the same amount of air reaches all the mixing points equally, leading to the flames that burn at the outlet of the main conduits 4b being similar, so a homogenous distribution of flames throughout the burner 1 is achieved.
The air inlet conduit 3, the gas inlet conduit 2 and the air and gas distribution means are independent from one another, i.e., the combustible gas and air are transported to the mixing area 7 in an independent manner and further in a fragmented manner through the different main conduits 4b and the different passage openings 5a of the distributor plate 5.
As has already been described, at the outlet of each main conduit 4b a mixing point is generated since it is there where the combustible gas and the oxygen contained in the air transported by the air distribution means will mix, the oxygen being necessary for combustion to occur, i.e., to generate the flame, when the ignition means are activated.
Likewise, since only combustible gas (oxygen-free) is transported through the inside of the main conduits 4b, flame flashback into the burner 1 is prevented, preventing the burner from being able to explode.
The mixing points generated at the outlet of all the main conduits 4b define the mixing area 7 of the burner 1, successfully improving the quality of the air-gas mixture in the burner 1 of the invention since this leads to the air-gas mixture in said mixing area 7 being homogenous, which will give rise to the formation of homogenous flames throughout the burner 1.
The combustible gas used in the preferred embodiment of the invention is hydrogen, although it is also possible to use natural gas, liquefied petroleum gas, such as propane or butane, as well as hydrogenated mixtures of natural gas and/or biogas which can comprise up to 25% or even up to 50% of hydrogen.
In the preferred embodiment of the invention, each main conduit 4b is configured in the form of a tube and each passage opening 5a of the distributor plate 5' is a circular hole arranged coaxially with a respective main conduit 4b, as seen in Figure 4, the diameter of said passage opening 5a logically being larger than the corresponding main conduit 4b to allow the passage of air through the distributor plate 5' and the respective main gas conduit 4b. In a non-limiting example, the diameter of the passage opening 5a is twice the diameter of the corresponding main conduit 4b.
In the preferred embodiment of the invention, the air passage openings 5a are at the same height as the outlets of the main gas conduits 4b, as seen in Figures 3, 4 or 5, i.e., the outer surface of the distribution plate 5' is arranged at the same height as the outlets of the main conduits 4b.
Optionally, in a variant not shown in the drawings, the air passage openings 5a are arranged above the main gas conduits 4b.
In another variant not shown in the drawings, the air passage openings 5a are arranged below the main gas conduits 4b.
These two variants are intended for favoring, according to need and to the properties of the combustible gas used, the mixing of combustible gas with air to assure the correct ignition.
The distributor plate 5' of the preferred embodiment of the invention comprises a reduced thickness in comparison with the height of the structure 1A of the burner 1, as seen in Figure 4, said thickness being the smallest possible thickness so that said plate 5' can withstand the high temperatures to which it will be subjected when the burner 1 is in use without deforming excessively.
The material of the distributor plate 5' according to the preferred embodiment of the invention is steel, preferably steel that is resistant to high temperatures. above 900°C for example.
In the preferred embodiment of the invention, the passage openings 5a have the same section along the entire width of the distribution plate 5', as seen in the detail of Figure 4, i.e., the wall of the passage openings 5a is a straight wall.
However, in a variant of the invention not shown in the drawings, the section of the passage openings 5a increases along the width of the distribution plate 5' in the air exit direction.
In another variant of the invention not shown in the drawings, the section of the passage openings 5a decreases along the width of the distribution plate 5' in the air exit direction.
These variants, like the variants described above, are also intended for favoring, according to need and to the properties of the combustible gas used, the mixing of combustible gas with air to assure the correct ignition. Likewise, it would also be possible to combine all these variants with one another, or with the preferred embodiment, for optimizing the correct mixing of combustible gas and air.
According to the preferred embodiment of the invention, the gas distribution means comprise a main chamber 4 which is communicated with the gas inlet conduit 2 as well as with each main conduit 4b, as seen in Figures 2 or 3. Said main chamber 4 is independent of the air chamber 5, i.e., both chambers 4 and 5 are not communicated with one another.
In the preferred embodiment of the invention, the main chamber 4 as well as the gas inlet conduit 2 are arranged in the lower part of the burner 1, the air chamber 5 being arranged above the main chamber 4 and the air conduit 3 being arranged above the gas conduit 2. Both chambers 4 and 5 are separated by a separation plate 8, as shown in Figures 3, 4 or 5.
The gas distribution means of the gas burner 1 of the invention comprise a constricted area 4a between the main chamber 4 and each main conduit 4b. In the preferred embodiment of the invention, there is one constricted area 4a for each main conduit 4b such that each main conduit 4b is communicated with the main chamber 4 through a respective constricted area 4a, as seen in Figure 3. Said constricted areas 4a allow regulating combustible gas head loss so that all the main conduits 4b conduct the same amount of combustible gas.
The constricted areas 4a are arranged in the lower part of the separation plate 8, one of the ends of each constricted area 4a being in contact with the main chamber 4. The corresponding main conduits 4b are arranged in contact with the other end of each constricted area 4a, said main conduits 4b being housed in a corresponding housing comprised in the separation plate 8. Each housing is arranged after a corresponding constricted area 4a.
The cross-section of the main conduits 4b is larger than the section of the constricted areas 4a, as shown in Figures 3, 4 or 5. The speed of the combustible gas directed to the corresponding mixing point in all the main conduits 4b is therefore slowed down.
Likewise, to assure uniformity of the flames at all the mixing points, the sections and lengths of all the constricted areas 4a are the same, as well as of all the main conduits 4b. This thereby assures that the same amount of gas reaches all the mixing points and with the same intensity, therefore, the flame generated in all the mixing points will be similar, which favors a homogenous distribution of the flames in the mixing area 7, giving rise to uniform heat distribution in said mixing area 7.
In the preferred embodiment of the invention, the main chamber 4 comprises a cross-section which gradually decreases as it moves away from the gas inlet conduit 2, as shown in Figure 3, resembling a triangular cross-section. The speed of the combustible gas in all the constricted areas 4a can thereby be kept equal.
As seen in the drawings, the main conduits 4b of the distribution means are parallel to one another, said main conduits 4b in the preferred embodiment of the invention being arranged in a staggered manner, as shown in Figures 2 or 4.
In order to make the flames generated in the mixing area 7 even more uniform and homogenous, the gas burner 1 according to the preferred embodiment of the invention comprises a ceramic structure 6, preferably of silicon carbide fibers, arranged on the mixing area 7, said ceramic structure 6 being fixed preferably on the distribution plate 5'. In Figures 2 and 4, said ceramic structure 6 has been depicted in a transparent manner to favor understanding of the drawings.
The ceramic structure 6 is a porous structure and the flames generated at each mixing point can be partially contained inside said ceramic structure 6, flame peaks that may give rise to a poor operation of the gas boiler 1 being prevented.
As a result of the ceramic structure 6, combustible gas and air blend together so that the air-gas mixture also expands horizontally, i.e., according to a direction substantially perpendicular to the gas exit direction of the corresponding main conduit 4b, such that a homogenous distribution of the air-gas mixture is obtained not only in the gas exit direction of the main conduits 4b, but also in a direction perpendicular to it. Therefore, the distribution of flames obtained in the mixing area 7 will be a uniform and homogenous distribution throughout the entire burner 1, flame peaks and valleys being prevented.
In a non-limiting example of the invention, the length of the gas burner 1 is in a range between 100 mm and 200 mm, the width is in a range between 80 mm and 120 mm and the height is in a range between 25 mm and 40 mm.
The gas burner 1 of the invention is suitable to be used in a gas boiler, preferably in a domestic boiler as a result of its small dimensions, giving rise to a safe and reliable boiler where it is assured that heat distribution throughout the entire burner 1 is homogenous, while at the same time preventing flame flashback.

Claims

Gas burner for a gas boiler, comprising a structure (1A), said structure (1A) comprising gas distribution means configured for directing combustible gas to a mixing area (7), said distribution means being communicated with a gas inlet conduit (2), and air distribution means configured for directing air to the mixing area (7), said gas distribution means being communicated with an air inlet conduit (3), characterized in that the gas distribution means comprise a plurality of main conduits (4b) communicated with the gas inlet conduit (2) and configured for transporting combustible gas to the mixing area (7) providing a mixing point at the outlet of each main conduit (4b), and the air distribution means comprising an air chamber (5) communicated with the air inlet conduit (3), at least part of each main conduit (4b) being housed in said air chamber (5), said air distribution means also comprising a distributor plate (5') arranged in the mixing area (7) comprising a plurality of passage openings (5a), each passage opening (5a) being configured for directing air to at least one mixing point.
Gas burner according to claim 1, wherein each main conduit (4b) is configured in the form of a tube and each passage opening (5a) of the distributor plate (5') is a circular hole arranged coaxially with a respective main conduit (4b).
Gas burner according to claim 2, wherein the air passage openings (5a) are at the same height as the outlets of the main gas conduits (4b).
Gas burner according to claim 2, wherein the air passage openings (5a) are arranged above or below the outlets of the main gas conduits (4b).
Gas burner according to any of the preceding claims, wherein the passage openings (5a) have the same section along the entire width of the distribution plate (5').
Gas burner according to any of claims 1 to 4, wherein the section of the passage openings (5a) increases along the width of the distribution plate (5') in the air exit direction.
Gas burner according to any of the preceding claims, wherein the gas distribution means comprise a main chamber (4) which is communicated with the gas inlet conduit (2) and with each main conduit (4b).
Gas burner according to claim 7, wherein said main chamber (4) comprises a cross-section which gradually decreases as it moves away from the gas inlet conduit (2).
Gas burner according to claim 7 or 8, wherein the gas distribution means comprise a constricted area (4a) between the main chamber (4) and each main conduit (4b).
Gas burner according to claim 9, wherein each main conduit (4b) is communicated with the main chamber (4) through a respective constricted area (4a).
Gas burner according to any of the preceding claims, wherein the main conduits (4b) of the distribution means are parallel to one another.
Gas burner according to claim 10, wherein the main conduits (4b) of the gas distribution means are arranged in a staggered manner.
Gas burner according to any of the preceding claims, wherein the burner (1) also comprises a ceramic structure (6), preferably of silicon carbide fibers, arranged on the mixing area (7).
Gas burner according to claim 13, wherein the ceramic structure (6) is fixed on the distribution plate (5').
Gas boiler characterized in that it comprises at least one gas burner (1) according to any of the preceding claims.