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
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/46—Details, e.g. noise reduction means
  • F23D14/48—Nozzles
  • F23D14/58—Nozzles characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration
• • 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
  • F23D14/46—Details, e.g. noise reduction means
  • F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
  • F23D14/74—Preventing flame lift-off
• • 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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2203/00—Gaseous fuel burners
  • F23D2203/10—Flame diffusing means
  • F23D2203/103—Flame diffusing means using screens
• • 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
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2209/00—Safety arrangements
  • F23D2209/20—Flame lift-off / stability
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2212/00—Burner material specifications
  • F23D2212/10—Burner material specifications ceramic
  • F23D2212/103—Fibres
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2212/00—Burner material specifications
  • F23D2212/20—Burner material specifications metallic
  • F23D2212/201—Fibres
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
  • F23D2900/00003—Fuel or fuel-air mixtures flow distribution devices upstream of the outlet

Definitions

• the present invention relates to a high-stability burner. Particularly, the present invention relates to a high-stability burner for gas boilers.
• Prior art gas boiler comprise: a duct for feeding a burner with a pre-mixed gas-air mixture, a burner for the production of heat by means of combustion of said mixture in a combustion chamber, and optionally a support element that can be connected to the heat exchanger and/or feed conduct in order to ensure the locking of the combustion chamber and/or for the positioning of the burner relative to this combustion chamber .
• the burner further comprises a diffuser for the pre-mixed gas of fuel and air to be conveyed therethrough and which defines a flame pattern for producing heat.
• the diffuser usually comprises a wall provided with a plurality of openings and having an inner surface fluidically connected to the feed duct, and accordingly in contact with the unburnt mixture, and an outer surface on which the burning is carried out. These surfaces are designated herein as the feed surface and burning surface .
• a distribution device, or distributor Upstream of the diffuser (with reference to the flow direction of the gas-air mixture) a distribution device, or distributor, can be further provided.
• the distributor usually comprises a wall provided with a plurality of openings, configured such as to distribute the gas-air mixture in a substantially uniform manner, or in any case as desired, towards the diffuser wall.
• the diffuser openings and the distributor openings are positioned at portions which, in the operating position, result to be matching to each other. In most cases, these portions are central portions of the distributor and diffuser.
• the heat produced by the combustion of the combustion surface is carried by means of the hot combustion gases to a heat exchanger for heating a fluid, for example water, which is subsequently conveyed to utility equipment, for example a heating system for an industrial process, of dwelling environments or the like and/or sanitary water .
• the heating power of the burner can be piloted by changing the flow rate of the fuel or mixture fed to the diffuser.
• the amplitude of the heating power range, i.e. the so-called modulation (ratio of minimum power to maximum power) of prior art burners is limited. This is due to the fact that, when the mixture flow rate is not comprised within an optimum range which depends on the material, the specific passage area (ratio of the passage area to the wall area) and on the diffuser flow resistance, flame instability problems occur, which prevent the proper operation of the burner.
• the object of the present invention is thus to provide a high- stability burner which allows a high power modulation while overcoming said problems of flame blow-off and the consequent polluting emission.
• a burner for gas boiler comprising:
• a diffuser suitable to diffuse pre-mixed combustion gases into a combustion chamber, comprising a wall provided with a plurality of diffusion openings;
• a distributor suitable to distribute the combustion gases on the diffuser, comprising a wall provided with a plurality of distribution openings;
• the diffusion openings are positioned at a diffuser portion and the distribution openings are positioned at a distribution portion, said portions being configured such that, in the operating position, the distribution openings result to be alternated with the diffusion openings relative to the mixture flow direction.
• each straight line parallel to the mixture flow direction i.e. substantially orthogonal to the burner, univocally intersects a distribution opening or a diffusion opening.
• each straight line substantially orthogonal to the burner only intersects the distributor portion in which the distribution openings are provided or the diffuser portion in which the diffusion openings are provided.
• This burner achieves, with the diffuser surface being the same, an increase in the burner maximum work power, without being affected by flame blow-off problems. Accordingly, it achieves an increase in the maximum power per surface unit of the diffuser (maximum specific power) . This implies an increase in the modulation range.
• the burner of the invention further obtains, with the power being the same, a reduction in the diffuser surface and accordingly a reduction in the costs, in addition to an increase in the maximum specific power.
• the reduction in the diffuser surface implies a reduction in the burner volume with obvious advantages in terms of manufacturing and transport of the latter.
• the flame stability that can be obtained with the burner of the invention results in reduced emissions of CO, because a flame less blown- off from the burner is less polluting.
• openings herein means through openings .
• said diffuser portion in which the diffusion openings are positioned corresponds to a central portion of the diffuser and said distributor portions in which the distribution openings are positioned corresponds to a peripheral portion of the distributor .
• - Fig. 1 is a longitudinal sectional view of a boiler portion comprising a high- stability burner according to the present invention
• - Fig. 2 is a longitudinal sectional view of a high stability burner according to a first embodiment of the invention
• - Fig. 3 is a longitudinal sectional view of a burner for a gas boiler according to the prior art
• FIG. 4 is a longitudinal sectional view of a high stability burner according to a second embodiment of the invention.
• a high stability burner for a gas boiler is generally designated with numeral reference 1.
• the reference 1 designates a burner that produces heat by means of the combustion of a pre-mixed fuel gas, generally comprising fuel gas and air.
• a pre-mixed fuel gas generally comprising fuel gas and air.
• these combustion gases are completely pre-mixed, i.e. no further component is added to the mixture delivered to the burner.
• the burner 1 comprises a diffuser 2, which is suitable to diffuse combustion gases into a combustion chamber 3 (indicated with a dotted line in Fig. 1) .
• the burner 1 is mounted to a frame 9.
• the latter can be connected to the combustion chamber 3 by means of connecting portions.
• the frame 9 further defines an opening for the mixture of fuel and air to pass therethrough.
• the diffuser 2 includes a wall provided with a plurality of diffusion openings 5.
• the inner surface of this wall is fluidically connected with the gas feeding duct and is accordingly called the feeding surface.
• the outer surface of this wall i.e. the surface on which the combustion is carried out, is called the combustion surface.
• the burner 1 also comprises a distributor 4, suitable to distribute the mixture to the diffuser 2, which is arranged upstream of the diffuser 2, with reference to the mixture flow direction 7.
• the distributor 4 comprises a wall provided with a plurality of distribution openings 6.
• the diffusion openings 5 are positioned at a diffuser portion 2 and the distribution openings 6 are positioned at a distribution portion 4. These portions are configured such that, in the operating position, the distribution openings 6 result to be alternated with the diffusion openings 5 relative to the mixture flow direction 7.
• the mixture flow direction 7 as outlined in Fig. 1-4 with arrows with which the numeral 7 is associated, is substantially orthogonal to the burner 1.
• the distribution openings 6 correspond to the diffusion openings 5 and accordingly a straight line parallel to the mixture 7 flow direction that crosses the former also crosses the latter, in the burner 1 of the present invention, a straight line parallel to the mixture 7 flow direction only crosses the distribution openings 6 or the diffusion openings 5.
• a straight line parallel to the mixture flow direction 7 only crosses the diffuser portion 2 in which the diffusion openings 5 are provided or the distributor portion 4 in which the distribution openings 6 are provided. This line, accordingly, does not cross both the diffuser portion 2 in which the diffusion openings 5 are provided and the distributor portion 4 in which the distribution openings 6 are provided, as it happens in the prior art.
• the distributor openings 4 are provided, the diffuser openings 2 are not provided, and vice versa.
• said portion of diffuser 2 in which the diffusion openings 5 corresponds to a central portion of the diffuser 2 and said portion of distributor 4 in which the distribution openings 6 are positioned corresponds to a peripheral portion of the distributor 4.
• the burner 1 is of a flat type, particularly rectangular, and said peripheral portion of the distributor 4, in which the distribution openings 6 are positioned, comprises a perimeter portion of the distributor 4, i.e. it extends at the four perimeter edges of the distributor 4.
• the burner 1 is of a three-dimensional type, particularly cylindrical, and said peripheral portion of the distributor 4, having the distribution openings 6, comprises a portion extending at the upper edge and a portion at the lower edge of the distributor 4.
• this peripheral portion having the distribution openings 6 comprises a portion at only one of said upper and lower edges.
• a heat exchanger 8 is schematically illustrated in contact with the combustion chamber 3, which is suitable to receive the heat produced from the combustion on the combustion surface of the diffuser 2.
• the diffuser 2 is preferably made from a compact material having said diffusion openings 5.
• It can comprise, at the portions having the diffusion openings 5, a net or a yarn- or fiber-woven wire- or ceramic mesh or a metal or ceramic sintered material .
• the distributor 4 comprises a plate which can be pierced or micro-stretched at those portions having the distribution openings 6.
• it can comprise, at the portions having the distribution openings 6, a wire net or a porous material .
• the burner 1 could be an inner combustion hollow burner, such that described in the US patent application 12/213, 078 in the name of the same Applicant.

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Family Cites Families (28)

• 2010
  • 2010-11-24 IT ITMI2010A002181A patent/IT1402900B1/it active
• 2011
  • 2011-11-18 WO PCT/IB2011/055177 patent/WO2012069970A1/en active Application Filing
  • 2011-11-18 CN CN201180056823.0A patent/CN103299130B/zh not_active Expired - Fee Related
  • 2011-11-18 EP EP11811373.7A patent/EP2643634A1/de not_active Withdrawn
  • 2011-11-18 US US13/989,062 patent/US20130302741A1/en not_active Abandoned

Non-Patent Citations (1)

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