EP3752770A1 - Cylindrical premix gas burner - Google Patents

Cylindrical premix gas burner

Info

Publication number
EP3752770A1
EP3752770A1 EP19701888.0A EP19701888A EP3752770A1 EP 3752770 A1 EP3752770 A1 EP 3752770A1 EP 19701888 A EP19701888 A EP 19701888A EP 3752770 A1 EP3752770 A1 EP 3752770A1
Authority
EP
European Patent Office
Prior art keywords
burner
openings
perforated plate
cylindrical
flange
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Withdrawn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
EP19701888.0A
Other languages
German (de)
French (fr)
Inventor
Jelmer DORSCHMAN
Harshit Gupta
Dirk Ten Hoeve
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.)
Bekaert Combustion Technology BV
Original Assignee
Bekaert Combustion Technology BV
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 Bekaert Combustion Technology BV filed Critical Bekaert Combustion Technology BV
Publication of EP3752770A1 publication Critical patent/EP3752770A1/en
Withdrawn legal-status Critical Current

Links

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
    • 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
    • F23D2203/00—Gaseous fuel burners
    • F23D2203/10—Flame diffusing means
    • F23D2203/102—Flame diffusing means using perforated plates
    • F23D2203/1023—Flame diffusing means using perforated plates with specific free passage areas

Definitions

  • the invention relates to cylindrical premix gas burners that can be equipped with an ionization pen for measurement and use of the ionization current of the flame in the control of the air to gas ratio in the premix supply in a broad burner modulation range.
  • EP2037175A2 discloses a premix burner comprising a tubular body and closed on a head by a plate.
  • the side surface of the burner has a plurality of holes and slits; the side surface provides the burner deck of the burner.
  • the burner comprises at least one disk provided with a plurality of through openings or holes constituting the distribution head of the air-gas mixture into the burner body.
  • the surface of the premix burner shows a substantial temperature evenness in operation, achieved thanks to the uniform gas distribution on the burner deck.
  • gas adaptive burner control is meant that the ratio of air to gas in the premix supply to the burner is controlled.
  • EP1036984A1 discloses a premix gas burner having a burner deck which includes a plurality of mixture flow openings; and an ionization electrode connected to a control device.
  • the control device is provided to derive a signal representative of the air ratio from the ionization current of the electrode.
  • the surface load of the premix gas burner is increased in the area of the ionization electrode by increasing the mixture flow area of the burner deck in the area of the ionization electrode.
  • WO2013/107661 A1 discloses a cylindrical gas premix burner comprising a cylindrical burner deck.
  • the cylindrical burner deck comprises a metal plate.
  • the cylindrical burner deck has a perforated zone.
  • the perforated zone is the part of the cylindrical burner deck foreseen with perforations in the metal plate.
  • the burner further comprises an end cap and an inlet for gas premix at the opposite side of the end cap.
  • the perforated zone comprises - seen along the axis of the cylindrical gas premix burners - at least three sections: a first section at the inlet, a third section located towards the end cap, and a second section located between the first section and the third section.
  • the porosity of the second section of the cylindrical burner deck is at least 50 percent higher than the porosity of the cylindrical burner deck in the first section; and than the porosity in the third section.
  • the cylindrical gas premix burner can be used in combination with an ionization pen for efficient control of the air to gas ratio over a broad load range of the cylindrical gas premix burner.
  • WO2008/142531A2 discloses a burner including a diffuser in which first openings and second openings are provided for the passage of a mixture of fuel and air delivered to the burner.
  • a distributing element is arranged inside the burner near and parallel to the diffuser and is provided with further first openings and further second openings for the passage of the mixture.
  • An ionization sensor is arranged near a zone of the surface of the diffuser in a direction substantially parallel to the surface of the diffuser.
  • the first openings are shaped as holes and the second openings are shaped as slits.
  • Two rows of slits are provided in the zone where the ionization sensor is positioned. These rows are separated by a surface portion of the diffuser devoid of openings.
  • the further second openings in the distributing element are arranged at the zone of the diffuser where the ionization sensor is provided.
  • the further second openings have a distribution other than the distribution of the further first openings and/or dimensions greater than the dimensions of the further first openings.
  • DE202016105039U1 discloses a gas burner comprising a burner interior space and a flow distributing device.
  • the flow distributing device has an inner surface with a hole pattern and a combustor burner surface facing away from the interior space.
  • the combustor burner surface has a hole pattern onto which the gas-air mixture is combusted.
  • a rod-shaped ionization current sensor is provided at the burner flame side surface. Extending parallel to and close to this ionization current sensor, a first surface region of the burner surface having smaller opening-hole structure is provided in the combustor burner surface.
  • a second surface area with a larger degree of opening-hole structure is provided in the combustor burner surface.
  • the hole pattern of the inner surface of the flow distributing device is constant in the axial direction of the ionization current sensor.
  • EP2177830A1 discloses a burner having an ionization electrode arranged within a flame range of a burner surface.
  • the electrode is provided for detecting the ionization current which depends on the combustion of the gas-air mixture.
  • a mixture supply chamber for gas-air mixture is provided.
  • a section of the mixture supply chamber is assigned to the ionization electrode and is separated by a partition wall from the other sections of the mixture supply chamber.
  • the supply chamber is formed such that the gas-air mixture in the section assigned to the ionization electrode possesses a higher pressure than in the other sections of the mixture supply chamber.
  • the first aspect of the invention is a cylindrical gas premix burner.
  • the burner comprises a cylindrical perforated plate onto which combustion is stabilized when the burner is in use, a mixing chamber surrounded by the cylindrical perforated plate, an end cap attached at the first end of the cylindrical perforated plate for closing off the mixing chamber, and a flange attached at and onto the second end of the cylindrical perforated plate.
  • the flange comprises a flat ring-shaped section for mounting the burner into a heating appliance, an upstanding ridge onto which the cylindrical perforated plate is attached; and a circular section for supplying premix gas into the mixing chamber. The circular section is fully provided within the boundaries of the cylindrical perforated plate.
  • the circular section comprises one or a plurality of first openings for supplying premix gas into the mixing chamber.
  • the one or the plurality of first openings is provided according to a regular pattern, more preferably around the centre of the circular section.
  • the circular section comprises within a - and preferably within one single - circle sector one or a plurality of second openings for the supply of premix gas into the mixing chamber.
  • the circle sector has a central angle of at least 30° and less than 120°.
  • the combined open area of the one or the plurality of second openings is at least 8 %, and preferably at least 10 %, and more preferably at least 12 %, of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate.
  • the mixing chamber is free from any object restricting or redirecting the flow of premix gas from the circular section of the flange to the cylindrical perforated plate.
  • the inventive burner provides a simple construction. A burner with only three parts
  • cylindrical perforated plate, end cap and flange can be used for air to gas ratio control in a broad modulation range via measurement of the ionization current of the combustion flame. Also at low burner power, a good ionization current signal is measured.
  • an ionization pen can be positioned at the cylindrical perforated plate to measure the ionization current in the combustion flame, by positioning the ionization pen at the one second opening or at the combination of the plurality of second openings. The one or the plurality of second openings is provided to establish an increased flow of premix gas towards a segment of the cylindrical perforated plate, segment at which an ionization pen can be positioned.
  • the second opening(s) ensure that more premix gas will be available at the cylindrical perforated plate at the position of the ionization pen. It has further been observed that the inventive burner produces less carbon monoxide (CO) at full burner load compared to gas premix burners in which the porosity of the burner deck and/or the gas permeable area of the burner deck have been enlarged locally at the position of the ionization pen to facilitate ionization current measurement. Furthermore, the burner according to the invention has a longer lifetime compared to gas premix burners in which the porosity of the burner deck and/or the gas permeable area of the burner deck have been enlarged locally at the position of the ionization pen to facilitate ionization current measurement.
  • the flat ring shaped section of the flange spans the full 360° of the cylindrical perforated plate.
  • the combined open area of the one or the plurality of second openings is at least 12%, more preferably at least 14% of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate.
  • the combined open area of the one or the plurality of second openings is less than 36% of the area of the cross section of the cylindrical volume enclosed by the cylindrical perforated plate. More preferably, the combined open area of the one or the plurality of second openings is less than 25%, more preferably less than 20%, even more preferably less than 15%, of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate.
  • the first openings have a circular cross section.
  • the circular section does not comprise openings within a distance of 3 mm from the cylindrical perforated plate; more preferably the circular section does not comprise openings within a distance of 5 mm from the cylindrical perforated plate.
  • the combined open area of the one or the plurality of first openings is less than 10%, more preferably less than 8%, more preferably less than 7% of the area of the cross section of the cylindrical volume enclosed by the cylindrical perforated plate.
  • the circle sector has a central angle of at least 75° and less than 120°.
  • the circle sector has a central angle of at least 50° and less than 90°.
  • the circle sector has a central angle of at least 45° and less than 60°.
  • the circular section is flat over it entire surface.
  • the cylindrical perforated plate comprises - positioned at the flange - a
  • the cylindrical perforated plate comprises - positioned at the end cap - a cylindrical ring without perforations.
  • all second openings have a bigger size than each of the first openings.
  • the flat ring-shaped section of the flange comprises a through hole provided for the installation of an ionization pen through the through hole.
  • the through hole can be provided as a perforation in the flat ring-shaped section.
  • the through hole can be slot shaped, such that the ionization pen can be slided into the slot shaped through hole.
  • the through hole is provided at the one second opening or at the combination of the plurality of second openings. More preferably, the through hole is provided substantially centered with respect to the one or to the combination of the plurality of second openings.
  • the burner is provided with an ionization pen protruding through the through hole in the flat ring-shaped section of the flange.
  • the burner comprises an ionization pen provided at the cylindrical perforated plate to measure the ionization current in the combustion flame.
  • an ionization pen is provided substantially centered with respect to the one or to the combination of the plurality of second openings.
  • the ionization pen is connected to a control device.
  • the control device is provided to derive from the ionization current a signal representative of the air ratio of the gas premix.
  • a first opening comprises the centre of the circular section of the flange.
  • the one or the plurality of second openings are slit shaped and preferably provided at the flange parallel with the circumference of the cylindrical perforated plate. More preferably, the slit is curved thereby following the circular curve of the circumference of the cylindrical perforated plate.
  • the one or the plurality of second openings is wedge shaped; preferably the wedge is directed from the centre towards the circumference of the circular section of the flange. Meant is that the bigger size of the wedge is oriented towards the circumference of the circular section of the flange.
  • each of the one or of the plurality of second openings is along its full circumference surrounded by a flat section of the circular section.
  • the length of the cylindrical perforated plate is less than the diameter of the cylindrical burner. Surprisingly, such burner has provided better ionization current measurements at low burner load.
  • the combined area of the one or the plurality of first openings is less than the combined area of the one or the plurality of second openings.
  • the combined area of the one or the plurality of second openings is at least double the combined area of the one or the plurality of first openings.
  • the circular section comprises a plurality of first openings for
  • the plurality of first openings are provided according to a regular pattern; preferably around the centre of the circular section.
  • the regular pattern of the first openings is interrupted by the one or a plurality of second openings.
  • the first openings are circular openings provided on parallel lines, with a phase shift of the position of the circular openings from a first line to the next line, preferably, the phase shift is 180°.
  • the first openings have a circular cross section, preferably with diameter less than 2.6 mm, more preferably with diameter less than 2.1 mm, more preferably with diameter less than 1.6 mm.
  • the circular section of the flange is flat over its entire surface.
  • the porosity of the segment of the circular section comprising the plurality of first openings is less than 15%, preferably less than 12%, more preferably less than 10%.
  • one of the first openings comprises the centre of the flange.
  • the first opening comprising the centre of the flange is provided by a tubular body, preferably wherein the tubular body is integrally formed out of the flange material.
  • the tubular body has a length at least 5% of the length of the cylindrical gas premix burner.
  • the circular section comprises only one first opening.
  • the circular planar section comprises only one second opening.
  • the first opening comprising the centre of the flange and provided by the tubular body has a surface area at least 15% of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate.
  • a second aspect of the invention is a heat cell.
  • the heat cell comprises a heat exchanger and a burner as in the first aspect of the invention.
  • the burner is provided to produce flue gas for heating a medium flowing through the heat exchanger.
  • Figure 1 shows a cylindrical gas premix burner according to the invention.
  • Figures 2 and 3 show examples of flanges as can be used in the inventive cylindrical gas premix burner of figure 1.
  • Figure 1 shows a cylindrical gas premix burner 100 according to the invention.
  • cylindrical gas premix burner comprises a cylindrical perforated plate 102 onto which combustion is stabilized when the burner is in use, a mixing chamber surrounded by the cylindrical perforated plate, an end cap 104 attached at the first end of the cylindrical perforated plate for closing off the mixing chamber, and a flange 106 attached at and onto the second end of the cylindrical perforated plate.
  • the mixing chamber is free from any object restricting or redirecting the flow of premix gas from the circular section of the flange to the cylindrical perforated plate.
  • premix gas is supplied into the mixing chamber via the flange.
  • the premix gas flows from the mixing chamber through the perforations of the cylindrical perforated plate to be combusted at the outside of the cylindrical perforated plate.
  • the length L 66 mm of the cylindrical perforated plate is less than the diameter D 70 mm of the cylindrical burner.
  • Figures 2 and 3 show examples 206, 306 of such flanges as can be used in the invention.
  • the flange comprises a flat ring-shaped section 208, 308 for mounting the burner into a heating appliance; an upstanding ridge 210, 310 onto which the cylindrical perforated plate is attached; and a circular section 212, 312 for supplying premix gas into the mixing chamber.
  • the flat ring shaped section of the flange spans the full 360° of the cylindrical perforated plate.
  • the circular section 212, 312 comprises one or a plurality of first openings 214, 314 for supplying premix gas into the mixing chamber.
  • the circular section comprises within a circle sector 216, 316 - which has a central angle a of at least 30° and less than 120° - one or a plurality of second openings 218, 318 for the supply of premix gas into the mixing chamber.
  • the flat ring-shaped section of the flange can comprise one or a plurality of screw holes 120, 220, 320 for the fixation of the burner via the flange into a heating appliance.
  • the flat ring-shaped section 208, 308 of the flange comprises a through hole 122, 222, 322 provided for the installation of an ionization pen through the through hole.
  • the exemplary burner of figure 1 comprises an ionization pen 124 provided at the cylindrical perforated plate to measure the ionization current in the combustion flame.
  • the ionization pen is connected to a control device, constructed to derive from the ionization current a signal representative of the air ratio in the premix gas.
  • Figure 2 shows an example of a flange 206 that can be used in the inventive cylindrical gas premix burner of figure 1.
  • the circular section 212 has a diameter 70 mm.
  • the circular section 212 is flat over its entire surface.
  • the circular section comprises within a circle sector 216 with central angle a 60° one second opening 218.
  • the second opening is along its full circumference surrounded by a flat section of the circular section.
  • the second opening 218 is wedge shaped; the wedge is directed from the centre towards the circumference of the circular section of the flange.
  • the second opening has a surface area of 14.1 % of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate (which is also the area of the circular section of the flange).
  • the circular section comprises a plurality of circular first openings 214 for supplying gas into the mixing chamber.
  • Each of the first openings has a diameter 1 .5 mm; in total 1 19 first openings are provided, resulting in a combined open area provided by the first openings of 5.5 % of the of the cross section of the cylindrical volume enclosed by cylindrical perforated plate (which is also the area of the circular section of the flange).
  • the first openings 214 are provided according to a regular pattern: the first openings 214 are provided on parallel lines with a phase shift of 180° of the position of the circular openings from a first line to the next line; the distance between neighboring first openings is 5 mm.
  • the regular pattern of the first openings 214 is interrupted by the second opening 218.
  • the flat ring-shaped section of the flange comprises a through hole 222 provided for the installation of an ionization pen through the through hole.
  • the ionization pen is provided at the second opening 218, more precisely, the ionization pen is provided substantially centered with respect to the second opening 218.
  • Figure 3 shows another example of a flange 306 that can be used in the inventive
  • the circular section 312 has a diameter 70 mm.
  • the circular section comprises within a circle sector 316 with central angle a 60° one second opening 218.
  • the second opening is along its full circumference surrounded by a flat section of the circular section.
  • the second opening 318 is slit shaped and at the flange parallel with the circumference of the cylindrical perforated plate.
  • the second opening has a surface area of 9 % of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate (which is also the area of the circular section of the flange).
  • the circular section 312 comprises one first opening 314 - at the centre of the circular section - for supplying gas into the mixing chamber.
  • the first opening is provided by a tubular body, integrally formed out of the flange material.
  • the surface area of the first opening is 10.5 % of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate (which is also the area of the circular section of the flange).
  • the circular section of the flange of figure 3 does not comprise openings (thus no first openings and no second openings) within a distance of 5 mm from the upstanding ridge 310, onto which the cylindrical perforated plate will be attached.
  • the flat ring-shaped section of the flange comprises a slot shaped through hole 322 provided for the installation of ionization pen through the slot shaped through hole.
  • the ionization pen is provided at the second opening 318, more precisely, the ionization pen is provided substantially centered with respect to the second opening 318.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Gas Burners (AREA)

Abstract

A cylindrical gas premix burner comprises a cylindrical perforated plate onto which combustion is stabilized when the burner is in use, a mixing chamber surrounded by the cylindrical perforated plate, an end cap attached at the first end of the cylindrical perforated plate for closing off the mixing chamber, and a flange attached at and onto the second end of the cylindrical perforated plate. The flange comprises a flat ring-shaped section for mounting the burner into a heating appliance, an upstanding ridge onto which the cylindrical perforated plate is attached; and a circular section for supplying premix gas into the mixing chamber. The circular section comprises one or a plurality of first openings for supplying premix gas into the mixing chamber. The circular section comprises within a circle sector one or a plurality of second openings for the supply of premix gas into the mixing chamber. The circle sector has a central angle of at least 30° and less than 120°. The combined open area of the one or the plurality of second openings is at least 8 % of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate. The mixing chamber is free from any object restricting or redirecting the flow of premix gas from the circular section of the flange to the cylindrical perforated plate.

Description

Cylindrical premix gas burner
Description
Technical Field
[1] The invention relates to cylindrical premix gas burners that can be equipped with an ionization pen for measurement and use of the ionization current of the flame in the control of the air to gas ratio in the premix supply in a broad burner modulation range.
Background Art
[2] Cylindrical premix gas burners are known. EP2037175A2 discloses a premix burner comprising a tubular body and closed on a head by a plate. The side surface of the burner has a plurality of holes and slits; the side surface provides the burner deck of the burner. The burner comprises at least one disk provided with a plurality of through openings or holes constituting the distribution head of the air-gas mixture into the burner body. According to EP2037175A2, thanks to the at least one disk provided with a plurality of through openings or holes, the surface of the premix burner shows a substantial temperature evenness in operation, achieved thanks to the uniform gas distribution on the burner deck.
[3] There is a tendency towards gas adaptive burner control over a broad modulation range of the burner. With gas adaptive burner control is meant that the ratio of air to gas in the premix supply to the burner is controlled.
[4] EP1036984A1 discloses a premix gas burner having a burner deck which includes a plurality of mixture flow openings; and an ionization electrode connected to a control device. The control device is provided to derive a signal representative of the air ratio from the ionization current of the electrode. The surface load of the premix gas burner is increased in the area of the ionization electrode by increasing the mixture flow area of the burner deck in the area of the ionization electrode.
[5] WO2013/107661 A1 discloses a cylindrical gas premix burner comprising a cylindrical burner deck. The cylindrical burner deck comprises a metal plate. The cylindrical burner deck has a perforated zone. The perforated zone is the part of the cylindrical burner deck foreseen with perforations in the metal plate. The burner further comprises an end cap and an inlet for gas premix at the opposite side of the end cap. The perforated zone comprises - seen along the axis of the cylindrical gas premix burners - at least three sections: a first section at the inlet, a third section located towards the end cap, and a second section located between the first section and the third section. The porosity of the second section of the cylindrical burner deck is at least 50 percent higher than the porosity of the cylindrical burner deck in the first section; and than the porosity in the third section. The cylindrical gas premix burner can be used in combination with an ionization pen for efficient control of the air to gas ratio over a broad load range of the cylindrical gas premix burner.
[6] WO2008/142531A2 discloses a burner including a diffuser in which first openings and second openings are provided for the passage of a mixture of fuel and air delivered to the burner. A distributing element is arranged inside the burner near and parallel to the diffuser and is provided with further first openings and further second openings for the passage of the mixture. An ionization sensor is arranged near a zone of the surface of the diffuser in a direction substantially parallel to the surface of the diffuser. The first openings are shaped as holes and the second openings are shaped as slits. Two rows of slits are provided in the zone where the ionization sensor is positioned. These rows are separated by a surface portion of the diffuser devoid of openings. The further second openings in the distributing element are arranged at the zone of the diffuser where the ionization sensor is provided. The further second openings have a distribution other than the distribution of the further first openings and/or dimensions greater than the dimensions of the further first openings.
[7] DE202016105039U1 discloses a gas burner comprising a burner interior space and a flow distributing device. The flow distributing device has an inner surface with a hole pattern and a combustor burner surface facing away from the interior space. The combustor burner surface has a hole pattern onto which the gas-air mixture is combusted. At the burner flame side surface a rod-shaped ionization current sensor is provided. Extending parallel to and close to this ionization current sensor, a first surface region of the burner surface having smaller opening-hole structure is provided in the combustor burner surface. On both sides of the first surface area and parallel to the ionization current sensor, a second surface area with a larger degree of opening-hole structure is provided in the combustor burner surface. At the ionization current sensor the hole pattern of the inner surface of the flow distributing device is constant in the axial direction of the ionization current sensor.
[8] EP2177830A1 discloses a burner having an ionization electrode arranged within a flame range of a burner surface. The electrode is provided for detecting the ionization current which depends on the combustion of the gas-air mixture. A mixture supply chamber for gas-air mixture is provided. A section of the mixture supply chamber is assigned to the ionization electrode and is separated by a partition wall from the other sections of the mixture supply chamber. The supply chamber is formed such that the gas-air mixture in the section assigned to the ionization electrode possesses a higher pressure than in the other sections of the mixture supply chamber.
Disclosure of Invention
[9] The first aspect of the invention is a cylindrical gas premix burner. The burner comprises a cylindrical perforated plate onto which combustion is stabilized when the burner is in use, a mixing chamber surrounded by the cylindrical perforated plate, an end cap attached at the first end of the cylindrical perforated plate for closing off the mixing chamber, and a flange attached at and onto the second end of the cylindrical perforated plate. The flange comprises a flat ring-shaped section for mounting the burner into a heating appliance, an upstanding ridge onto which the cylindrical perforated plate is attached; and a circular section for supplying premix gas into the mixing chamber. The circular section is fully provided within the boundaries of the cylindrical perforated plate. The circular section comprises one or a plurality of first openings for supplying premix gas into the mixing chamber. Preferably, the one or the plurality of first openings is provided according to a regular pattern, more preferably around the centre of the circular section. The circular section comprises within a - and preferably within one single - circle sector one or a plurality of second openings for the supply of premix gas into the mixing chamber. The circle sector has a central angle of at least 30° and less than 120°. The combined open area of the one or the plurality of second openings is at least 8 %, and preferably at least 10 %, and more preferably at least 12 %, of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate. The mixing chamber is free from any object restricting or redirecting the flow of premix gas from the circular section of the flange to the cylindrical perforated plate.
[10] The inventive burner provides a simple construction. A burner with only three parts
(cylindrical perforated plate, end cap and flange) can be used for air to gas ratio control in a broad modulation range via measurement of the ionization current of the combustion flame. Also at low burner power, a good ionization current signal is measured. To this end, an ionization pen can be positioned at the cylindrical perforated plate to measure the ionization current in the combustion flame, by positioning the ionization pen at the one second opening or at the combination of the plurality of second openings. The one or the plurality of second openings is provided to establish an increased flow of premix gas towards a segment of the cylindrical perforated plate, segment at which an ionization pen can be positioned. The second opening(s) ensure that more premix gas will be available at the cylindrical perforated plate at the position of the ionization pen. It has further been observed that the inventive burner produces less carbon monoxide (CO) at full burner load compared to gas premix burners in which the porosity of the burner deck and/or the gas permeable area of the burner deck have been enlarged locally at the position of the ionization pen to facilitate ionization current measurement. Furthermore, the burner according to the invention has a longer lifetime compared to gas premix burners in which the porosity of the burner deck and/or the gas permeable area of the burner deck have been enlarged locally at the position of the ionization pen to facilitate ionization current measurement.
[11] Preferably, the flat ring shaped section of the flange spans the full 360° of the cylindrical perforated plate.
[12] Preferably, the combined open area of the one or the plurality of second openings is at least 12%, more preferably at least 14% of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate.
[13] Preferably, the combined open area of the one or the plurality of second openings is less than 36% of the area of the cross section of the cylindrical volume enclosed by the cylindrical perforated plate. More preferably, the combined open area of the one or the plurality of second openings is less than 25%, more preferably less than 20%, even more preferably less than 15%, of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate.
[14] Preferably, the first openings have a circular cross section.
[15] Preferably, the circular section does not comprise openings within a distance of 3 mm from the cylindrical perforated plate; more preferably the circular section does not comprise openings within a distance of 5 mm from the cylindrical perforated plate.
[16] Preferably, the combined open area of the one or the plurality of first openings is less than 10%, more preferably less than 8%, more preferably less than 7% of the area of the cross section of the cylindrical volume enclosed by the cylindrical perforated plate.
[17] Preferably, when the cylindrical perforated plate has a diameter less than 60 mm, the circle sector has a central angle of at least 75° and less than 120°.
[18] Preferably, when the cylindrical perforated plate has a diameter between 60 mm and 85 mm, the circle sector has a central angle of at least 50° and less than 90°.
[19] Preferably, when the cylindrical perforated plate has a diameter more than 85 mm, the circle sector has a central angle of at least 45° and less than 60°.
[20] Preferably, the circular section is flat over it entire surface.
[21] Preferably, the cylindrical perforated plate comprises - positioned at the flange - a
cylindrical ring without perforations.
[22] Preferably, the cylindrical perforated plate comprises - positioned at the end cap - a cylindrical ring without perforations.
[23] Preferably, all second openings have a bigger size than each of the first openings.
[24] Preferably, the flat ring-shaped section of the flange comprises a through hole provided for the installation of an ionization pen through the through hole. The through hole can be provided as a perforation in the flat ring-shaped section. Alternatively the through hole can be slot shaped, such that the ionization pen can be slided into the slot shaped through hole. More preferably, the through hole is provided at the one second opening or at the combination of the plurality of second openings. More preferably, the through hole is provided substantially centered with respect to the one or to the combination of the plurality of second openings. More preferably, the burner is provided with an ionization pen protruding through the through hole in the flat ring-shaped section of the flange.
[25] Preferably, the burner comprises an ionization pen provided at the cylindrical perforated plate to measure the ionization current in the combustion flame.
[26] Preferably, an ionization pen is provided substantially centered with respect to the one or to the combination of the plurality of second openings.
[27] Preferably when the burner comprises an ionization pen, the ionization pen is connected to a control device. The control device is provided to derive from the ionization current a signal representative of the air ratio of the gas premix.
[28] Preferably, a first opening comprises the centre of the circular section of the flange.
[29] In a preferred embodiment, the one or the plurality of second openings are slit shaped and preferably provided at the flange parallel with the circumference of the cylindrical perforated plate. More preferably, the slit is curved thereby following the circular curve of the circumference of the cylindrical perforated plate.
[30] In a preferred embodiment, the one or the plurality of second openings is wedge shaped; preferably the wedge is directed from the centre towards the circumference of the circular section of the flange. Meant is that the bigger size of the wedge is oriented towards the circumference of the circular section of the flange.
[31] In a preferred embodiment, each of the one or of the plurality of second openings is along its full circumference surrounded by a flat section of the circular section. Surprisingly, such burners have shown to provide more stable ionization current measurement, as such burners can be manufactured to a more stable design than if the second opening(s) continue in the burner up to the cylindrical perforated plate.
[32] Preferably, the length of the cylindrical perforated plate is less than the diameter of the cylindrical burner. Surprisingly, such burner has provided better ionization current measurements at low burner load.
[33] Preferably, the combined area of the one or the plurality of first openings is less than the combined area of the one or the plurality of second openings. Preferably, the combined area of the one or the plurality of second openings is at least double the combined area of the one or the plurality of first openings. With“combined area of the one or the plurality of first openings” is meant the sum of the surface area of all the first openings. With “combined area of the one or the plurality of second openings” is meant the sum of the surface area of all the second openings.
[34] In a preferred burner, the circular section comprises a plurality of first openings for
supplying gas into the mixing chamber. The plurality of first openings are provided according to a regular pattern; preferably around the centre of the circular section. The regular pattern of the first openings is interrupted by the one or a plurality of second openings. In a preferred regular pattern, the first openings are circular openings provided on parallel lines, with a phase shift of the position of the circular openings from a first line to the next line, preferably, the phase shift is 180°. Preferably, the first openings have a circular cross section, preferably with diameter less than 2.6 mm, more preferably with diameter less than 2.1 mm, more preferably with diameter less than 1.6 mm. Preferably, the circular section of the flange is flat over its entire surface.
[35] Preferably, the porosity of the segment of the circular section comprising the plurality of first openings is less than 15%, preferably less than 12%, more preferably less than 10%.
[36] In a preferred burner, one of the first openings comprises the centre of the flange. The first opening comprising the centre of the flange is provided by a tubular body, preferably wherein the tubular body is integrally formed out of the flange material. Preferably, the tubular body has a length at least 5% of the length of the cylindrical gas premix burner. More preferably, the circular section comprises only one first opening. More preferably, the circular planar section comprises only one second opening. Preferably, the first opening comprising the centre of the flange and provided by the tubular body has a surface area at least 15% of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate.
[37] A second aspect of the invention is a heat cell. The heat cell comprises a heat exchanger and a burner as in the first aspect of the invention. The burner is provided to produce flue gas for heating a medium flowing through the heat exchanger.
Brief Description of Figures in the Drawings
[38] Figure 1 shows a cylindrical gas premix burner according to the invention.
Figures 2 and 3 show examples of flanges as can be used in the inventive cylindrical gas premix burner of figure 1.
Mode(s) for Carrying Out the Invention
[39] Figure 1 shows a cylindrical gas premix burner 100 according to the invention. The
cylindrical gas premix burner comprises a cylindrical perforated plate 102 onto which combustion is stabilized when the burner is in use, a mixing chamber surrounded by the cylindrical perforated plate, an end cap 104 attached at the first end of the cylindrical perforated plate for closing off the mixing chamber, and a flange 106 attached at and onto the second end of the cylindrical perforated plate. The mixing chamber is free from any object restricting or redirecting the flow of premix gas from the circular section of the flange to the cylindrical perforated plate. When the burner is in use, premix gas is supplied into the mixing chamber via the flange. The premix gas flows from the mixing chamber through the perforations of the cylindrical perforated plate to be combusted at the outside of the cylindrical perforated plate.
[40] In the example of figure 1 , the length L 66 mm of the cylindrical perforated plate is less than the diameter D 70 mm of the cylindrical burner. The length L of the burner is provided by a blind (= non-perforated) length h 12 mm at the flange, a perforated length h 44 mm and a blind (= non-perforated) length I3 10 mm at the end cap.
[41] Figures 2 and 3 show examples 206, 306 of such flanges as can be used in the invention.
The flange comprises a flat ring-shaped section 208, 308 for mounting the burner into a heating appliance; an upstanding ridge 210, 310 onto which the cylindrical perforated plate is attached; and a circular section 212, 312 for supplying premix gas into the mixing chamber. The flat ring shaped section of the flange spans the full 360° of the cylindrical perforated plate. The circular section 212, 312 comprises one or a plurality of first openings 214, 314 for supplying premix gas into the mixing chamber. The circular section comprises within a circle sector 216, 316 - which has a central angle a of at least 30° and less than 120° - one or a plurality of second openings 218, 318 for the supply of premix gas into the mixing chamber. The flat ring-shaped section of the flange can comprise one or a plurality of screw holes 120, 220, 320 for the fixation of the burner via the flange into a heating appliance.
[42] The flat ring-shaped section 208, 308 of the flange comprises a through hole 122, 222, 322 provided for the installation of an ionization pen through the through hole. The exemplary burner of figure 1 comprises an ionization pen 124 provided at the cylindrical perforated plate to measure the ionization current in the combustion flame. The ionization pen is connected to a control device, constructed to derive from the ionization current a signal representative of the air ratio in the premix gas.
[43] Figure 2 shows an example of a flange 206 that can be used in the inventive cylindrical gas premix burner of figure 1. In order to fit the burner with diameter D 70 mm of figure 1 , the circular section 212 has a diameter 70 mm. The circular section 212 is flat over its entire surface. The circular section comprises within a circle sector 216 with central angle a 60° one second opening 218. The second opening is along its full circumference surrounded by a flat section of the circular section. The second opening 218 is wedge shaped; the wedge is directed from the centre towards the circumference of the circular section of the flange. The second opening has a surface area of 14.1 % of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate (which is also the area of the circular section of the flange).
[44] The circular section comprises a plurality of circular first openings 214 for supplying gas into the mixing chamber. Each of the first openings has a diameter 1 .5 mm; in total 1 19 first openings are provided, resulting in a combined open area provided by the first openings of 5.5 % of the of the cross section of the cylindrical volume enclosed by cylindrical perforated plate (which is also the area of the circular section of the flange). The first openings 214 are provided according to a regular pattern: the first openings 214 are provided on parallel lines with a phase shift of 180° of the position of the circular openings from a first line to the next line; the distance between neighboring first openings is 5 mm. The regular pattern of the first openings 214 is interrupted by the second opening 218.
[45] The circular section of the flange of figure 2 does not comprise openings (no first
openings and no second openings) within a distance of 5 mm from the upstanding ridge 210 onto which the cylindrical perforated plate will be attached.
[46] The flat ring-shaped section of the flange comprises a through hole 222 provided for the installation of an ionization pen through the through hole. When an ionization pen is installed through the hole, the ionization pen is provided at the second opening 218, more precisely, the ionization pen is provided substantially centered with respect to the second opening 218.
[47] Figure 3 shows another example of a flange 306 that can be used in the inventive
cylindrical gas premix burner of figure 1. In order to fit the burner with diameter D 70 mm of figure 1 , the circular section 312 has a diameter 70 mm. The circular section comprises within a circle sector 316 with central angle a 60° one second opening 218. The second opening is along its full circumference surrounded by a flat section of the circular section. The second opening 318 is slit shaped and at the flange parallel with the circumference of the cylindrical perforated plate. The second opening has a surface area of 9 % of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate (which is also the area of the circular section of the flange).
[48] The circular section 312 comprises one first opening 314 - at the centre of the circular section - for supplying gas into the mixing chamber. The first opening is provided by a tubular body, integrally formed out of the flange material. The surface area of the first opening is 10.5 % of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate (which is also the area of the circular section of the flange).
[49] The circular section of the flange of figure 3 does not comprise openings (thus no first openings and no second openings) within a distance of 5 mm from the upstanding ridge 310, onto which the cylindrical perforated plate will be attached.
[44] The flat ring-shaped section of the flange comprises a slot shaped through hole 322 provided for the installation of ionization pen through the slot shaped through hole. When an ionization pen is installed through the hole, the ionization pen is provided at the second opening 318, more precisely, the ionization pen is provided substantially centered with respect to the second opening 318.

Claims

Claims
1. Cylindrical gas premix burner (100), comprising
- a cylindrical perforated plate (102) onto which combustion is stabilized when the burner is in use,
- a mixing chamber surrounded by the cylindrical perforated plate,
- an end cap (104), attached at the first end of the cylindrical perforated plate, for closing off the mixing chamber, and
- a flange (106) attached at and onto the second end of the cylindrical perforated plate;
wherein the flange comprises
- a flat ring-shaped section (208, 308) for mounting the burner into a heating appliance; and
- a circular section (212, 312) for supplying premix gas into the mixing chamber;
wherein the mixing chamber is free from any object restricting or redirecting the flow of premix gas from the circular section of the flange to the cylindrical perforated plate;
characterized in that the flange comprises an upstanding ridge (210, 310) onto which the cylindrical perforated plate is attached; and
wherein the circular section (212, 312) comprises one or a plurality of first openings (214, 314) for supplying premix gas into the mixing chamber;
wherein the circular section comprises within a circle sector (216, 316) one or a plurality of second openings (218, 318) for the supply of premix gas into the mixing chamber,
wherein the circle sector has a central angle of at least 30° and less than 120°;
wherein the combined open area of the one or the plurality of second openings is at least 8 % of the area of the cross section of the cylindrical volume enclosed by cylindrical perforated plate, .
2. Burner as in claim 1 ; wherein the flat ring shaped section (208, 308) of the flange (106) spans the full 360° of the cylindrical perforated plate.
3. Burner as in any of the preceding claims; wherein all second openings (218, 318) have a
bigger size than each of the first openings.
4. Burner as in any of the preceding claims; wherein the flat ring-shaped section of the flange comprises a through hole (122, 222, 322) provided for the installation of an ionization pen (124) through the through hole.
5. Burner as in any of the preceding claims 1 - 4;
wherein the burner comprises an ionization pen (124) ,
wherein the ionization pen is provided at the cylindrical perforated plate to measure the ionization current in the combustion flame,
wherein the ionization pen is provided at the one second opening or at the combination of the plurality of second openings.
6. Burner as in claim 5, wherein the ionization pen (124) is provided substantially centered with respect to the one or to the combination of the plurality of second openings.
7. Burner as in any of the preceding claims 5 or 6, wherein the ionization pen is connected to a control device, wherein the control device is provided to derive from the ionization current a signal representative of the air ratio in the premix gas.
8. Burner as in any of the claims 1 - 7; wherein the one or the plurality of second openings is/are wedge shaped; preferably wherein the wedge is directed from the centre towards the circumference of the circular section of the flange.
9. Burner as in any of the claims 1 - 7; wherein the one or the plurality of second openings are slit shaped; and preferably at the flange parallel with the circumference of the cylindrical perforated plate.
10. Burner as in any of the claims 1 - 9, wherein each of the one or of the plurality of second
openings is along its full circumference surrounded by a flat section of the circular section.
11. Burner as in any of the preceding claims, wherein the length of the cylindrical perforated plate is less than the diameter of the cylindrical burner.
12. Burner as in any of the preceding claims; wherein the combined area of the one or the plurality of first openings is less than the combined area of the one or the plurality of second openings; preferably the combined area of the one or the plurality of second openings is at least double the combined area of the one or the plurality of first openings.
13. Burner as in any of the preceding claims 1 - 12;
wherein one of the first openings comprises the centre of the flange;
wherein the first opening comprising the centre of the flange is provided by a tubular body, preferably, the tubular body is integrally formed out of the flange material.
14. Burner as in claim 13; wherein the first opening comprising the centre of the flange and
provided by the tubular body has a surface area at least 15% of the area of the cross section of the cylindrical volume enclosed by the cylindrical perforated plate.
15. Heat cell comprising a heat exchanger and a burner as in any of the preceding claims, wherein the burner is provided to produce flue gas for heating a medium flowing through the heat exchanger.
EP19701888.0A 2018-02-14 2019-02-04 Cylindrical premix gas burner Withdrawn EP3752770A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP18156595 2018-02-14
PCT/EP2019/052637 WO2019158382A1 (en) 2018-02-14 2019-02-04 Cylindrical premix gas burner

Publications (1)

Publication Number Publication Date
EP3752770A1 true EP3752770A1 (en) 2020-12-23

Family

ID=61223772

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19701888.0A Withdrawn EP3752770A1 (en) 2018-02-14 2019-02-04 Cylindrical premix gas burner

Country Status (2)

Country Link
EP (1) EP3752770A1 (en)
WO (1) WO2019158382A1 (en)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19912076A1 (en) 1999-03-18 2000-09-21 Kromschroeder Ag G Premix burner for gaseous fuels
ITMO20070167A1 (en) 2007-05-21 2008-11-22 Worgas Bruciatori Srl MODULATING BURNER
ITMI20071751A1 (en) 2007-09-12 2009-03-13 Polidoro S P A PREMIXED BURNER
EP2177830A1 (en) 2008-10-16 2010-04-21 Siemens Building Technologies HVAC Products GmbH Gas burner for a combined gas-air control system
EP2805111B1 (en) 2012-01-19 2018-07-04 Bekaert Combustion Technology B.V. Cylindrical gas premix burner
CN109196275B (en) * 2016-05-13 2020-02-04 贝卡尔特燃烧技术股份有限公司 Cylindrical gas premixing burner
WO2017194394A1 (en) * 2016-05-13 2017-11-16 Bekaert Combustion Technology B.V. Gas premix burner with a cylindrical burner deck
DE202016105039U1 (en) 2016-09-12 2017-09-14 Viessmann Werke Gmbh & Co Kg gas burner

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