EP4089328A1 - Membrane de combustion pour un brûleur à gaz - Google Patents

Membrane de combustion pour un brûleur à gaz Download PDF

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Publication number
EP4089328A1
EP4089328A1 EP22171830.7A EP22171830A EP4089328A1 EP 4089328 A1 EP4089328 A1 EP 4089328A1 EP 22171830 A EP22171830 A EP 22171830A EP 4089328 A1 EP4089328 A1 EP 4089328A1
Authority
EP
European Patent Office
Prior art keywords
perforated
combustion
sheets
layer
sheet
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.)
Withdrawn
Application number
EP22171830.7A
Other languages
German (de)
English (en)
Inventor
Massimo Gilioli
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.)
Beckett Thermal Solutions SRL
Original Assignee
Beckett Thermal Solutions SRL
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Beckett Thermal Solutions SRL filed Critical Beckett Thermal Solutions SRL
Publication of EP4089328A1 publication Critical patent/EP4089328A1/fr
Withdrawn legal-status Critical Current

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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
    • F23D14/12—Radiant burners
    • F23D14/14—Radiant burners using screens or perforated plates
    • F23D14/145—Radiant burners using screens or perforated plates combustion being stabilised at a screen or a perforated plate
    • 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
    • F23D14/12—Radiant burners
    • F23D14/14—Radiant burners using screens or perforated plates
    • F23D14/149—Radiant burners using screens or perforated plates with wires, threads or gauzes as radiation intensifying means
    • 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
    • F23D2203/106—Assemblies of different layers

Definitions

  • the present invention relates to a combustion membrane for a gas burner, in particular for a completely or partially premixed burner, for example for boilers, swimming pool heaters, hot air generators, or ovens for industrial processes.
  • Gas combustion systems comprise:
  • the feeding system usually comprises a fan, driven by an electric motor, for the suction and conveying of a flow of combustion air, as well as a solenoid valve for controlling a flow of combustible gas.
  • the known ignition systems comprise, for example, an ignition electrode which can be electrically fed to generate a combustion ignition spark.
  • the diffuser layer conventionally consists of a perforated metal sheet (highly heat resistant steel) with or without an additional outer layer of fabric or metal mesh or of porous ceramic.
  • the burner and combustion system For a desirable and satisfactory use of the burner and combustion system, on the one hand it is desirable to vary the heating power of the burner and the flow rate of combustible gas or mixture of combustible gas and combustion air flow rate in a controlled manner through the combustion membrane, and on the other hand, to ensure a safe and controllable operation of the burner, in particular a controllable and safe combustion without the risk of explosion or flashback also when combustible gases with high speed combustion are used.
  • perforated metal sheet as diffuser layer requires an affordable perforation process of the sheet and with speed adapted to mass industrial production.
  • This is currently possible only by means of a perforation process by mechanical press or die punching (cutting, punching holes) which however has intrinsic dimensional limits, that is the individual holes may be obtained with a hole diameter/sheet thickness ratio ⁇ 1 by mechanical punching.
  • the mechanical punching is not adapted to make perforations in which the diameter of the individual hole is significantly less than the thickness of the metal sheet.
  • the flashback phenomenon may be controlled or excluded according to the combustion speed of the gas used only by means of a high flow speed through the hole and/or increasing the length of the hole with respect to the diameter thereof.
  • At least part of the objects of the invention are achieved by means of a combustion membrane for a gas burner adapted to the combustion of gases having an increased combustion speed, for example hydrogen gas, and operated with or without pre-mixing the combustion gas, according to claim 1.
  • gases having an increased combustion speed for example hydrogen gas
  • the dependent claims relate to advantageous and preferred embodiments.
  • a combustion membrane for a gas burner forms an inner side to which a combustible gas is conveyed and an outer side on which the combustion of the combustible gas occurs after the crossing of the combustion membrane thereby
  • the combustion membrane comprises a layer made of perforated metal sheet, in which perforation holes of an individual sheet have a ratio between an equivalent diameter D of the hole and length S of the hole corresponding to thickness S of the individual sheet D/S which is greater than or equal to 1 (D/S ⁇ 1)
  • the layer made of perforated metal sheet comprises a plurality of said individual metal sheets overlapping in a pile of sheets and with said holes overlapping and aligned to form channels for the passage of the gas through the pile of sheets, in which said channels have a ratio D1/S1 between an equivalent diameter D1 of the channel and length S1 of the channel corresponding to thickness S1 of the pile of sheets which is less than 0.7 (D1/S1 ⁇ 0.7).
  • the effective perimeter is the one lapped by the fluid.
  • the equivalent diameter for a duct having circular section by definition corresponds to the geometrical diameter.
  • the perforation may be obtained with an affordable mechanical press perforation process on the individual sheet, and regulating the ratio D1/S1 between the equivalent diameter D1 and length S1 of the channel may be adjusted to prevent the flashback by means of the selection of the thickness and number of individual sheets to be overlapped in the pile of sheets.
  • the membrane structure further allows a simplification of the production and management and storage process of the perforated sheets or sheets to be perforated because different combustion membranes with different thicknesses of the layer of perforated sheet and with different diameter/length ratios of the perforation channels may be made with a single type of starting sheet having a single thickness (preferably thin), also for combustion applications with gas or gas mixtures not having very high combustion speeds.
  • the object of the invention is further achieved by a gas burner, in particular a partially or completely premixed gas burner, having the aforesaid combustion membrane.
  • a gas combustion system for example for a boiler, comprises:
  • the gas burner 2 comprises:
  • the burner 2 in figure 3 further has a tubular silencing accessory (without reference numeral), which is optional.
  • the gas burner 2 comprises:
  • a perforated distributor wall 21 can be positioned in order to distribute the combustible gas 13 in a desired manner towards the combustion membrane 14, 14' ( figure 4 ).
  • the combustion membrane 14, 14' forms an inner side 22 to which a combustible gas is conveyed and an outer side 17 on which the combustion of the combustible gas occurs after the crossing of the combustion membrane 14, 14'.
  • the combustion membrane 14, 14' comprises a layer made of perforated metal sheet 23, in which the perforation holes 24 of an individual sheet 25 have a ratio D/S between an equivalent diameter D of hole 24 and the length S of hole 24 corresponding to a thickness S of the individual sheet 25, which is greater than or equal to 1 (D/S ⁇ 1).
  • Layer 23 made of perforated metal sheet comprises a plurality of said individual metal sheets 25 overlapping in a pile of sheets and with said holes 24 overlapping and aligned to form channels 26 for the passage of gas 13 through the pile of sheets, in which said channels 26 have a ratio D1/S1 between an equivalent diameter D1 of channel 26 and the length S1 of channel 26 corresponding to thickness S1 of the pile of sheets which is less than 0.7 (D1/S1 ⁇ 0.7).
  • the holes 24 overlapping and aligned to form said channel 26 all have a substantially identical perimeter shape and the equivalent diameter D of the holes 24 is equal to the equivalent diameter D1 of channel 26.
  • all the individual metal sheets 25 of layer 23 have the same thickness S.
  • the individual metal sheets 25 of layer 23 have different thicknesses S, preferably exactly two different thicknesses S.
  • the intrados surfaces 27 of the holes 24 of the overlapping individual sheets 25 belonging to a same channel 26 are arranged flush between one another so as to give channel 26 a shape which substantially is without steps.
  • the intrados surfaces 27 of the holes 24 of the overlapping individual sheets 25 belonging to a same channel 26 are offset in direction transverse to the length of channel 26 in an offset range between zero to 1/5 of the equivalent diameter D1 of channel 26, preferably from zero to 1/10 of the equivalent diameter D1 of channel 26.
  • the holes 24 and the channels 26 preferably have a preferably concave circular or slot shape (view in direction of the flow of gas), that is to say without inversion of sign of curvature and without protrusions towards the inside of hole 24 or channel 26.
  • the layer of perforated sheet 23 may comprise from 2 to 10 overlapping individual perforated sheets 25.
  • Thickness S of the individual perforated sheets 25 may be in the range from 0.3 mm to 2 mm, preferably in the range from 0.5 mm to 2 mm, even more preferably in the range from 0.5 mm to 1 mm, preferably 0.6mm.
  • the ratio D/S between the equivalent diameter D and the length S of hole 24 is in the range of 1 to 2 (1 ⁇ D/S ⁇ 2), while ratio D1/S1 between the equivalent diameter D1 and the length S1 of channel 26 is less than 0.6, preferably in the range from 0.6 to 0.01, even more preferably in the range from 0.45 to 0.05.
  • the perforated sheets 25 are made by mechanical perforation, for example punching, of sheets not yet permanently fastened to one another, preferably by means of mechanical punching of individual sheets.
  • the individual sheets 25 are:
  • the bending of the perforated sheets 25 is carried out, for example by calendering or deformation by press.
  • connection to one another of the perforated sheets 25 of the layer of perforated sheet 23 advantageously occurs by welding, for example by means of temporary weld points 28 prior to the bending and/or by permanent means of weld beads 29 and/or permanent weld points 28.
  • connection to one another of the perforated sheets 25 of the layer of perforated sheet 23 comprises one or more welds arranged at, or in the vicinity of, initially free edges of the perforated sheets 25.
  • the combustion membrane 14 has a tubular shape, for example cylindrical or frustoconical, and the layer of perforated sheet 23 is made by bending and welding individual perforated sheets 25 to form a plurality of layers of individual tubular perforated sheet spaced apart from one another, and then mutually (telescopically) inserting said layers of individual tubular perforated sheet to form the layer of tubular perforated sheet 23.
  • the combustion membrane 14 has a tubular shape, for example cylindrical or frustoconical, and the layer of perforated sheet 23 is made by bending and/or calendering in a "C" shape and overlapping individual perforated sheets 25, possibly connected to one another by means of one or more temporary welds, to form the layer of perforated sheet 23 in the form of open channel with two free opposite longitudinal edges 30 ( figures 9, 10 ), and by means of successive matching and joining by means of welding the two opposite longitudinal edges 30 to form the layer of tubular perforated sheet 23.
  • the layer of perforated sheet 23 is made by bending and/or calendering in a "C" shape and overlapping individual perforated sheets 25, possibly connected to one another by means of one or more temporary welds, to form the layer of perforated sheet 23 in the form of open channel with two free opposite longitudinal edges 30 ( figures 9, 10 ), and by means of successive matching and joining by means of welding the two opposite longitudinal edges 30 to form the layer of tubular perforated sheet 23.
  • outer reference edges of the individual perforated sheets 25 are positioned and/or offset by means of a positioning mask/frame (not shown) and/or by means of one or more reference notches 31 ( figure 10 ) formed at the outer reference edges.
  • the individual perforated sheet or sheets 25 arranged on the inner side 22 of the combustion membrane 14 may be made of a different metal, for example less heat-resistant and less costly (because less exposed to the increased combustion temperatures), of a metal of the individual perforated sheet(s) 25 arranged or exposed on the outer side 17 of the combustion membrane 14.
  • the maximum outer diameter of the layer of perforated sheet 23 in cylindrical configuration is, for example 70 mm.
  • the longitudinal edges 30 thereof are connected to one another by means of a weld bead passing through all the layers of individual sheet and having trapeze cross section, preferably with lateral sides 32 having a step/s.
  • the combustion membrane 1 may further comprise an outer permeable layer 33 (only partially shown in figures 7, 8 ) without metal sheet, and which covers at least a perforation area of the layer of perforated sheet 23 on the outer side 17 of the combustion membrane 14, 14'.
  • the outer permeable layer 33 may comprise one or more:
  • fabric means a textile structure with an intertwining of threads or fibers, for example knitted (knitted fabric) or manufactured on a loom by intertwining warp threads with weft threads (fabric) according to a determined order and criterion.
  • a textile structure is intended as a substantially two-dimensional extension (flat or curved) in space and with a very reduced thickness with respect to the two-dimensional extension.
  • combustion gas 13 denotes:

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • Gas Burners (AREA)
EP22171830.7A 2021-05-10 2022-05-05 Membrane de combustion pour un brûleur à gaz Withdrawn EP4089328A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT102021000011888A IT202100011888A1 (it) 2021-05-10 2021-05-10 Membrana di combustione per un bruciatore a gas

Publications (1)

Publication Number Publication Date
EP4089328A1 true EP4089328A1 (fr) 2022-11-16

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP22171830.7A Withdrawn EP4089328A1 (fr) 2021-05-10 2022-05-05 Membrane de combustion pour un brûleur à gaz

Country Status (2)

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EP (1) EP4089328A1 (fr)
IT (1) IT202100011888A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2063803A5 (fr) * 1969-10-31 1971-07-09 Gaz De France
EP0536706A2 (fr) * 1991-10-08 1993-04-14 Lüdi, Roger Procédé pour la fabrication d'un stabilisateur de flamme pour un brûleur radiant et stabilisateur de flamme produit selon ce procédé
EP0631091A1 (fr) * 1993-06-21 1994-12-28 Mts S.A. Brûleur à gaz à faible taux de NOx
DE29511790U1 (de) * 1995-07-21 1996-11-14 Robert Bosch Gmbh, 70469 Stuttgart Atmosphärischer Gasbrenner

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2063803A5 (fr) * 1969-10-31 1971-07-09 Gaz De France
EP0536706A2 (fr) * 1991-10-08 1993-04-14 Lüdi, Roger Procédé pour la fabrication d'un stabilisateur de flamme pour un brûleur radiant et stabilisateur de flamme produit selon ce procédé
EP0631091A1 (fr) * 1993-06-21 1994-12-28 Mts S.A. Brûleur à gaz à faible taux de NOx
DE29511790U1 (de) * 1995-07-21 1996-11-14 Robert Bosch Gmbh, 70469 Stuttgart Atmosphärischer Gasbrenner

Also Published As

Publication number Publication date
IT202100011888A1 (it) 2022-11-10

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