EP0844436A1 - Gasbrenner - Google Patents

Gasbrenner Download PDF

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Publication number
EP0844436A1
EP0844436A1 EP96830594A EP96830594A EP0844436A1 EP 0844436 A1 EP0844436 A1 EP 0844436A1 EP 96830594 A EP96830594 A EP 96830594A EP 96830594 A EP96830594 A EP 96830594A EP 0844436 A1 EP0844436 A1 EP 0844436A1
Authority
EP
European Patent Office
Prior art keywords
casing
ports
burner according
flame
burner
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Withdrawn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
EP96830594A
Other languages
English (en)
French (fr)
Inventor
Feliciano Lasagni
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
Worgas Bruciatori 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 Worgas Bruciatori SRL filed Critical Worgas Bruciatori SRL
Priority to EP96830594A priority Critical patent/EP0844436A1/de
Publication of EP0844436A1 publication Critical patent/EP0844436A1/de
Withdrawn legal-status Critical Current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
    • F23D14/02—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
    • F23D14/04—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner
    • F23D14/10—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner with elongated tubular burner head
    • F23D14/105—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner with elongated tubular burner head with injector axis parallel to the burner head axis
    • 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

Definitions

  • the present invention relates to a gas burner, either of the atmospheric or premix type.
  • the invention relates in particular to a gas burner with a high resistance to stress resulting from thermal expansion.
  • Gas burners known in prior art may be divided into two categories, namely, atmospheric burners and premix burners.
  • Atmospheric burners usually comprise a tubular casing, closed at both ends and coaxially enclosing a venturi tube consisting of a converging portion, a cylindrical throat and a diverging portion.
  • the venturi tube may be a separate part fitted in the burner or it may form an integral part of the burner itself, made, for example, by die forming or other known methods.
  • the said tubular casing has a plurality of flame ports, usually at the top, designed to allow a combustion mixture of gas and air to flow out of it.
  • a nozzle injects gas into the opening of the venturi tube and, in accordance with the known principles of fluid mechanics, a certain quantity of air is also sucked into the opening of the venturi tube and mixes well with the gas in the aforesaid cylindrical throat
  • the gas/air mixture in the desired and controlled stoichiometric proportions, is then dynamically compressed in the said diverging portion, is discharged into the tubular casing and allowed through the said flame ports into the atmosphere where it is burnt.
  • tubular burners of both atmospheric and premix types, described below
  • modular "blade type” burners where a single, integral structure constitutes both the casing of the burner and its functional parts as described above for tubular burners; flame ports designed to allow the gas/air mixture into the atmosphere where it is burnt are made in this structure at suitable locations.
  • the gas and air are supplied by means (consisting typically of fans and mixers) which, in a manner similar to that achieved by the venturi device described above, create a premixture of gas and air outside the tubular casing and supply the combustion mixture to the aforesaid flame ports.
  • the mixture is ignited through auxiliary systems that do not form part of the subject-matter of the present invention.
  • the configuration and size of the aforesaid ports are such as to prevent the flame from returning into the tubular casing of the burner but to keep it adjacent to the outer surface of the casing.
  • the flame ports may assume many different sizes and configurations. For example, they may be continuous rows of slits or groups of slits arranged in chequered fashion, offset with respect to each other, or they may be appropriately distributed holes or combinations of slits and holes distributed in any of various different ways, made in a lateral portion (which may even coincide with the entire lateral surface) of the tubular casing which will hereafter be referred to as the "flame port area".
  • the distance of the flame front from the surface of the tubular casing depends on the type of gas used, on the gas supply pressure and on the shape of the burner. In all cases, because of the nearness of the flame to the said tubular casing, a portion of the tubular casing itself (namely, the flame port area), depending on the type and category of the burner, reaches extremely high temperatures, with peaks of up to 600°C and over. In particular, under certain operating conditions, not frequent in well designed and constructed burners but always possible even in these, the temperature of at least part of the wall of the tubular casing (that around the flame port area) may become so high as to produce considerable deformation, resulting in stress and strain, in particular on the sides of the tubular casing.
  • This deformation if excessive in that it is normally prevented, is permanent and may lead to burner breakage or malfunctioning even when the overheating ceases. In some cases, such deformation may also make it dangerous to continue using the burner, producing a risk of serious damage to the apparatus where it is fitted or even to the room where it is used.
  • the aim of the present invention is to overcome the disadvantages mentioned above by providing a burner capable of resisting abnormally high temperatures without being permanently deformed and without reducing its efficiency or giving rise to hazardous situations.
  • a gas burner of the type comprising a casing that encloses a mixing element capable, when used, of creating a mixture of gas and air inside the casing, there being made in a portion of the wall defining the lateral surface of the said casing a plurality of first flame ports defining a flame port area and designed to allow the combustion mixture of gas and air out of the casing, characterized in that the said portion has, in the flame port area, at least one second port consisting of a structural break, preferably a slot, substantially perpendicular to the longitudinal axis of the said casing.
  • the said burner preferably comprises a plurality of second ports consisting of slots parallel to each other and substantially perpendicular to the longitudinal axis of the said casing.
  • One of the advantages achieved by the present invention is basically that the burner casing (preferably of the tubular type), and in particular the part of it in and around the flame port area, can be subjected to extremely high temperatures without producing permanent deformations that can damage it or make its use dangerous.
  • the burner 1 comprises a tubular casing 2 extending lengthways along an axis 3 which, when the burner is in use, is horizontal.
  • the tubular casing 2 in cross section, forms a closed shape (in the embodiment illustrated, see Fig. 3, it is substantially ovoid in shape) with one end, illustrated on the right in Fig. 1, closed by a vertical end cap 5 and the other end, on the left-hand side, being closed by a flange 4 with a gas and air inlet port.
  • a mixing element consisting of a venturi tube 6 extending along an axis parallel to the axis 3 and comprising, from left to right in Fig. 1, a converging portion 7, a cylindrical throat 8 and a diverging portion 9.
  • a feeder element consisting of a nozzle 10, faces the inlet port of the tubular casing 2 through a hole 11 made in the central portion of the flange 4 (the inlet port mentioned above), being fitted at the inlet of the converging portion 7 so that, under operating conditions, it can inject a stream of gas into the converging portion 7 according to known injector technology.
  • a lateral portion 12 of the wall 13 defining the tubular casing 2, the upper portion in the embodiment illustrated (see Fig. 3 in particular), has an area with a plurality of flame ports, starting at distances L1 and L2 from the ends of the tubular casing 2 and hereafter also referred to as "flame port area" 12a.
  • the flame ports consist of a series of apertures 14 (preferably but not necessarily slits) parallel to each other and perpendicular to the aforesaid axis 3.
  • These generic flame ports 14 may be arranged in any manner, typically along one or more adjacent longitudinal rows (see Fig. 4) or in shorter polygonal groups arranged in line or in chequered fashion (see Fig. 5) or, as mentioned in the introduction, they may be circular, as illustrated in Fig. 6.
  • the upper portion 12 of the wall 13 also has a plurality of structural breaks, consisting preferably (but not necessarily), as shown in the embodiments illustrated in the drawings, of second ports or slots parallel to each other, perpendicular to the axis 3 and, with reference to the lengthways direction of the tubular casing 2, being longer than the aforementioned flame ports 14, the length of the latter being measured in the direction orthogonal to the axis 3.
  • the width of the second ports 15, measured in the lengthways direction of the tubular casing 2, is such that, during use, whatever the operating temperature (normal or exceptional) of the burner 1, and hence whatever the degree of thermal expansion of the upper portion 12 (and sections adjacent to it, in particular the flame port area 12a) of the wall 13 that defines the lateral surface of the tubular casing 2, the two adjacent (or opposing) edges of each second port can never come into contact with each other.
  • second ports 15 There may be any number of second ports 15 (even a single second port 15 made at the line through the centre of the tubular casing 2) and the distance between two consecutive second ports 15 is preferably greater than the distance separating two consecutive flame ports 14.
  • the second ports 15 are long enough to extend right across the area of the tubular casing 2 likely to reach excessive temperatures, that is to say, the aforementioned flame port area 12a, and in any case temperatures greater than the optimum operating temperature or any temperature significantly higher than that reached at the same time during use by the lower lateral portion of the wall 13.
  • the purpose of the structural breaks defining the said second ports 15 is to allow the free, unobstructed expansion of the portion of the lateral surface of the burner that is subjected to the highest temperatures.
  • the shape, number and distribution of the said second ports will depend on the design requirements of each burner, even though in the embodiments illustrated in Figs 1, 3, 7 and 8, the second ports are crossways slots perpendicular to the burner axis 3.
  • the gas is injected into the venturi tube 6 through the nozzle 10 and entrains a flow of air through an appropriate port (not illustrated) made in the aforementioned flange 4.
  • the streams of air and gas enter the converging portion 7 of the venturi tube 6 together and are well mixed before leaving the venturi tube 6 through the diverging portion 9.
  • the gas/air mixture then leaves the tubular casing 2 through the flame ports 14 and is ignited by known means outside the tubular casing 2 adjacent to the flame ports 14.
  • the tubular casing 2 When the burner 1 is cold, the tubular casing 2 has the nominal dimensions, depending on burner design, and is not subjected to stress.
  • the parts 16 of the upper portion 12 adjacent to the flame port area 12a and between each pair of consecutive second ports 15 (and between the walls 4 and 5 and the second ports 15 nearest to them) expand in the axial direction but this does not produce dangerous stress in the upper portion 12 since the presence of a second port 15 between each part 16 and the part 16 nearest to it, allows the parts 16 to expand freely. Indeed, as the temperature of the parts 16 changes, so the distance between opposite edges of the second ports 15 between pairs of consecutive parts 16 changes accordingly, that is to say, this distance decreases as the temperature rises and increases as the temperature falls.
  • the upper portion 12 of the tubular casing 2 remains free to expand lengthways in the axial direction and, therefore, the strain on the structure remains within safe limits whatever the temperature reached by the burner 1, since peak strain conditions are not produced because the axial expansion of the structure is not obstructed.
  • the burner 1 fully achieves the abovementioned aims in that the structure of the burner 1 is capable of withstanding overheating without producing permanent deformations that can reduce burner efficiency or give rise to hazardous situations.
  • the number of the second ports 15, the spacing between them and their width will obviously depend on the amount of expansion that is to be controlled and on the design of the tubular casing, the shape of the flame ports 14, the temperature differences expected between the hot and cold parts of the burner, the combustion chamber containing the burner, the materials used and so on. What is important is to be able to control the axial expansion of the flame port area 12a relative to the remaining portion of the tubular casing 2 so as to control the effect of the thermal expansion which the area 12a is subjected to as a result of the different temperature distribution on the tubular casing 2.
  • the second port(s) may also be made in the front and/or rear part of the lateral portion 12, that is, in the section or sections before and/or after the flame port area (labelled L1 and L2 in the drawings).
  • the additional second ports in this embodiment are labelled 15t in Fig. 2 and drawn with dashed lines.
  • the second ports 15, which in the embodiment illustrated in Fig. 10, are circular and labelled 15c, may be closed by suitable heat-resistant baffles 15s (attached, for example, to one side of the tubular casing at 15f) to prevent the mixture from issuing out of the said second ports.
  • suitable heat-resistant baffles 15s attached, for example, to one side of the tubular casing at 15f
  • such ports can be closed by an appropriately fitted piece of metal plate designed to prevent or significantly reduce the passage of mixture but without obstructing the expansion of the parts of the tubular casing as described above. The purpose of this is to prevent excessive quantities of unburnt mixture and/or undesirable emissions in the flue gases.
  • Fig. 2 indicates the generic element 6p for premixing the gas and air mixture outside the tubular casing 2, the said mixture being then forced into the tubular casing under pressure to reach the combustion area.
  • each of the said second ports 15 is divided into smaller ports (15') arranged one after the other along a curved line perpendicular to the axis 3 and separated from each other by very small portions of the wall 13.
  • the second ports consist simply of a crossways slot separating two contiguous parts of the flame port area 12a, of one or more holes 15n made just outside the flame port area and defining the part 16, or of a combination of these.
  • the invention can also be similarly applied to non-tubular burners, that is, to modular blade type burners, illustrated by way of example in Figs. 7 to 9 which show such burners in the atmospheric version, the application to premix burners of this type being obvious.
  • the reference numbers labelling the parts of the burner illustrated in Figs 7 to 9 are the result of adding one hundred to the reference numbers of the corresponding parts in Figs. 1 to 3.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Gas Burners (AREA)
EP96830594A 1996-11-26 1996-11-26 Gasbrenner Withdrawn EP0844436A1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP96830594A EP0844436A1 (de) 1996-11-26 1996-11-26 Gasbrenner

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP96830594A EP0844436A1 (de) 1996-11-26 1996-11-26 Gasbrenner

Publications (1)

Publication Number Publication Date
EP0844436A1 true EP0844436A1 (de) 1998-05-27

Family

ID=8226061

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96830594A Withdrawn EP0844436A1 (de) 1996-11-26 1996-11-26 Gasbrenner

Country Status (1)

Country Link
EP (1) EP0844436A1 (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999035439A1 (en) * 1998-01-02 1999-07-15 Worgas Bruciatori S.R.L. Tubular burner
US6139312A (en) * 1997-05-23 2000-10-31 Worgas Bruciatori S.R.L. Cylindrical gas burner
DE19961994A1 (de) * 1999-12-22 2001-07-12 Buderus Heiztechnik Gmbh Brennflächenperforation von Brennstäben
WO2005059437A1 (en) * 2003-12-10 2005-06-30 Worgas -Bruciatori - S.R.L. Bladed burner with mutual ignition means
WO2009151420A1 (en) * 2008-06-13 2009-12-17 Worgas Inc. Gas flame stabilization method and apparatus
CN104566379A (zh) * 2013-10-14 2015-04-29 陈凤利 燃气滞后的层状进气
CN110513681A (zh) * 2018-05-22 2019-11-29 沃加斯布鲁恰托里有限责任公司 模块化燃烧器

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8801383A (nl) * 1988-05-30 1989-12-18 Nefit Nv Metalen branderdek.
DE29514660U1 (de) * 1995-09-12 1995-12-07 Polidoro Aldo Atmosphärischer Gasbrenner vom sogenannten überstöchiometrischen Gemischtyp
EP0695911A1 (de) * 1994-07-08 1996-02-07 Worgas Bruciatori S.R.L. Gasbrenner mit einem verbesserten Diffusor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8801383A (nl) * 1988-05-30 1989-12-18 Nefit Nv Metalen branderdek.
EP0695911A1 (de) * 1994-07-08 1996-02-07 Worgas Bruciatori S.R.L. Gasbrenner mit einem verbesserten Diffusor
DE29514660U1 (de) * 1995-09-12 1995-12-07 Polidoro Aldo Atmosphärischer Gasbrenner vom sogenannten überstöchiometrischen Gemischtyp

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6139312A (en) * 1997-05-23 2000-10-31 Worgas Bruciatori S.R.L. Cylindrical gas burner
WO1999035439A1 (en) * 1998-01-02 1999-07-15 Worgas Bruciatori S.R.L. Tubular burner
DE19961994A1 (de) * 1999-12-22 2001-07-12 Buderus Heiztechnik Gmbh Brennflächenperforation von Brennstäben
DE19961994C2 (de) * 1999-12-22 2002-01-24 Buderus Heiztechnik Gmbh Brennflächenperforation von Brennstäben für atmosphärische Gasbrenner
WO2005059437A1 (en) * 2003-12-10 2005-06-30 Worgas -Bruciatori - S.R.L. Bladed burner with mutual ignition means
WO2009151420A1 (en) * 2008-06-13 2009-12-17 Worgas Inc. Gas flame stabilization method and apparatus
CN102057221B (zh) * 2008-06-13 2014-04-02 沃加斯公司 气体火焰稳定方法及设备
CN104566379A (zh) * 2013-10-14 2015-04-29 陈凤利 燃气滞后的层状进气
CN110513681A (zh) * 2018-05-22 2019-11-29 沃加斯布鲁恰托里有限责任公司 模块化燃烧器

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