EP0664420A1 - Atmospheric gas burner - Google Patents

Atmospheric gas burner Download PDF

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Publication number
EP0664420A1
EP0664420A1 EP95710002A EP95710002A EP0664420A1 EP 0664420 A1 EP0664420 A1 EP 0664420A1 EP 95710002 A EP95710002 A EP 95710002A EP 95710002 A EP95710002 A EP 95710002A EP 0664420 A1 EP0664420 A1 EP 0664420A1
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EP
European Patent Office
Prior art keywords
tube
primary air
venturi tube
fuel rod
orifices
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Withdrawn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
EP95710002A
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German (de)
French (fr)
Inventor
Heinrich Dipl.Ing. Oehler
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.)
Bosch Thermotechnik GmbH
Original Assignee
Buderus Heiztechnik GmbH
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Filing date
Publication date
Application filed by Buderus Heiztechnik GmbH filed Critical Buderus Heiztechnik GmbH
Publication of EP0664420A1 publication Critical patent/EP0664420A1/en
Withdrawn legal-status Critical Current

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    • 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
    • F23D14/62—Mixing devices; Mixing tubes
    • F23D14/64—Mixing devices; Mixing tubes with injectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F23D14/72—Safety devices, e.g. operative in case of failure of gas supply
    • F23D14/74—Preventing flame lift-off
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2203/00—Gaseous fuel burners
    • F23D2203/007—Mixing tubes, air supply regulation

Definitions

  • the invention relates to an atmospheric gas burner according to the preamble of claim 1.
  • the invention has for its object to change the supply of primary air to the fuel gas-air mixture in a highly premixed atmospheric gas burner without external control measures such that both a lifting of the flame with increased CO formation and a seated flame with increased NO x formation is prevented.
  • the atmospheric gas burner according to the invention is characterized by the features mentioned in claim 1.
  • One or more openings are arranged in the wall of each Venturi tube. In this way, a partial stream of the mixture can recirculate from the surrounding annular space of the combustion tube. Since the amount of gas supplied is determined by the gas nozzle diameter and the gas nozzle pressure, a more or less strong recirculation inevitably leads to a change in the amount of primary air drawn in. To counteract the flame being lifted off the fuel rod, the primary air flow must be reduced. This takes place through an increased recirculation of the mixture from the annular space of the fuel rod into the Venturi tube. However, the primary air flow must be increased to prevent the flame from sitting on the fuel rod. For this purpose, the recirculation must be reduced or completely prevented.
  • the recirculation openings should be arranged in the mouth area of the Venturi tube so that the primary air intake can be acted on directly at the mouth.
  • the flow cross-section of the openings should be variable. In this way it is possible to change the recirculation and thus the primary air intake.
  • the flow cross-section of the openings can be changed continuously depending on the fuel rod temperature, which means that the recirculation and the primary air intake are also continuously changed.
  • the openings are fully open at low fuel rod temperatures, ie when the flame is lifted and CO is increased.
  • the strong recirculation reduces the primary air intake.
  • the temperature of the fuel rod rises.
  • the openings are initially partially closed and completely above a defined surface temperature. The primary air intake rises and the fuel rod temperature drops again.
  • the fuel rod temperature can thus be set exactly to the appropriate level by influencing the primary air intake. Defects caused by temperatures that are too high or too low are excluded.
  • a venturi tube 2 is integrated in a fuel rod 1.
  • the gas G enters the venturi tube 2 from a gas nozzle and thereby sucks in the required primary air P.
  • the fuel gas / air mixture flows into the annular space 3 between the venturi tube 2 and the fuel rod 1. It then ignites at the perforated fuel rod surface and is burned there.
  • the suction of the primary air P is influenced by the fact that a partial flow of the mixture re-enters the Venturi tube 2 through openings 4. This recirculation affects the amount of primary air P drawn in.
  • the recirculation can be changed by means of bimetal flaps 5 which are adjustable as a function of temperature. These are attached to the inner wall of the fuel rod 1 via a bracket 6. You can fully open the opening 4 when the fuel rod temperature is high (Fig. 3, left) or close it completely at a low fuel rod temperature (Fig. 3, right). All intermediate levels must also be set.

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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)
  • Regulation And Control Of Combustion (AREA)

Abstract

The venturi tube (2) is concentric with burner housing (1) so as to form mix annulus (3). Tube wall has orifices (4) so as to recirculate part of flow from annulus into venturi tube to control primary air volume. Orifices (4) are arranged in tube inlet area and can be adjusted in flow section by bimetal flaps (5) so that orifices are fully open at low temperatures and totally closed from given temperature. In service, gas (G) passes from nozzle to venturi tube (2), drawing requisite primary air in with it (P), only to pass round in annulus from far end of tube where it ignites on tube surface. Amount of air drawn in (P) is function of recirculation through specified orifices (4), using bimetal flaps (5) for infinite adjustment.

Description

Die Erfindung betrifft einen atmosphärischen Gasbrenner nach dem Oberbegriff des Patentanspruches 1.The invention relates to an atmospheric gas burner according to the preamble of claim 1.

Bei hochvormischenden atmosphärischen Gasbrennern kann das Problem auftreten, daß bei niederkalorigem Gas, d.h. bei einem Gas mit geringem Wobbeindex, die Flammen vom Brennstab abheben. Bei konstantem Gasdüsendurchmesser und Gasdüsendruck liegt dann nämlich ein Überschuß an Primärluft vor, der das Abheben der Flamme und, insbesondere beim Kaltstart, eine erhöhte CO-Bildung zur Folge hat.With high premixing atmospheric gas burners the problem can arise that with low calorific gas, i.e. for a gas with a low Wobbe index, lift the flames off the fuel rod. With a constant gas nozzle diameter and gas nozzle pressure, there is then an excess of primary air, which results in the flame being lifted off and, particularly during a cold start, in increased CO formation.

Bei Gasen mit höherem Wobbeindex kann sich der entgegengesetzte Effekt mit einer auf dem Brennstab aufsitzenden Flamme ergeben. Das führt zu hohen Temperaturen der Brennstaboberfläche mit höheren NOx-Emissionen.For gases with a higher Wobbe index, the opposite effect can result with a flame sitting on the fuel rod. This leads to high temperatures of the fuel rod surface with higher NO x emissions.

Es wurden schon Überlegungen angestellt, die Zufuhr der Primärluft in Abhängigkeit von der Flammentemperatur oder einer sonstigen geeigneten Führungsgröße zu regeln. Zu diesem Zweck ist ein Meßorgang notwendig, das die entsprechenden Signale an ein Gebläse im Primärluftstrom sendet, wie es beispielsweise in der DE 39 18 855 A 1 vorgeschlagen wird. Das erfordert nicht nur einen entsprechenden regeltechnischen Aufwand. Die Frage eines sicheren Betriebes und einer ordnungsgemäßen Verbrennung während eines nicht auszuschließenden Gebläseausfalles ist auch nicht geklärt.Considerations have already been made to regulate the supply of primary air as a function of the flame temperature or another suitable control variable. For this purpose, a measuring process is necessary which sends the corresponding signals to a blower in the primary air flow, as is proposed, for example, in DE 39 18 855 A1. This not only requires a corresponding technical effort. The question of safe operation and proper combustion during a blower failure that cannot be ruled out has also not been resolved.

Der Erfindung liegt die Aufgabe zugrunde, bei einem hochvormischenden atmosphärischen Gasbrenner ohne äußere regeltechnische Maßnahmen die Zufuhr der Primärluft zum Brenngas-Luft-Gemisch derart zu verändern, daß sowohl ein Abheben der Flamme mit verstärkter CO-Bildung als auch ein Aufsitzen der Flamme mit verstärkter NOx-Bildung verhindert wird.The invention has for its object to change the supply of primary air to the fuel gas-air mixture in a highly premixed atmospheric gas burner without external control measures such that both a lifting of the flame with increased CO formation and a seated flame with increased NO x formation is prevented.

Der erfindungsgemäße atmosphärische Gasbrenner ist gekennzeichnet durch die im Patentanspruch 1 genannten Merkmale.The atmospheric gas burner according to the invention is characterized by the features mentioned in claim 1.

In der Wand eines jeden Venturirohres sind eine oder mehrere Öffnungen angeordnet. Auf diese Weise kann ein Teilstrom des Gemisches aus dem umgebenden Ringraum des Brennrohres rezirkulieren. Da die zugeführte Gasmenge durch den Gasdüsendurchmesser und den Gasdüsendruck festgelegt ist, führt eine mehr oder weniger starke Rezirkulation zwangsweise zu einer Veränderung der angesaugten Primärluftmenge. Um einem Abheben der Flamme vom Brennstab entgegenzuwirken, muß der Primärluftstrom reduziert werden. Das erfolgt durch eine verstärkte Rezirkulation des Gemisches aus dem Ringraum des Brennstabes in das Venturirohr hinein. Gegen das Aufsitzen der Flamme auf dem Brennstab muß hingegen der Primärluftstrom erhöht werden. Hierfür ist die Rezirkulation zu verringern bzw. ganz zu unterbinden.One or more openings are arranged in the wall of each Venturi tube. In this way, a partial stream of the mixture can recirculate from the surrounding annular space of the combustion tube. Since the amount of gas supplied is determined by the gas nozzle diameter and the gas nozzle pressure, a more or less strong recirculation inevitably leads to a change in the amount of primary air drawn in. To counteract the flame being lifted off the fuel rod, the primary air flow must be reduced. This takes place through an increased recirculation of the mixture from the annular space of the fuel rod into the Venturi tube. However, the primary air flow must be increased to prevent the flame from sitting on the fuel rod. For this purpose, the recirculation must be reduced or completely prevented.

Die Rezirkulations-Öffnungen sollten im Einmündungsbereich des Venturirohres angeordnet sein, damit direkt an der Einmündung auf die Primärluftansaugung eingewirkt werden kann. Dabei sollten die Öffnungen hinsichtlich ihres Strömungsquerschnittes veränderlich sein. Auf diese Weise ist es möglich, die Rezirkulation und damit die Primärluftansaugung zu verändern.The recirculation openings should be arranged in the mouth area of the Venturi tube so that the primary air intake can be acted on directly at the mouth. The flow cross-section of the openings should be variable. In this way it is possible to change the recirculation and thus the primary air intake.

Mit Bimetallklappen kann der Strömungsquerschnitt der Öffnungen stufenlos in Abhängigkeit von der Brennstabtemperatur verändert werden, wodurch dann auch die Rezirkulation und die Primärluftansaugung stufenlos verändert wird. Bei niedrigen Brennstabtemperaturen, d.h. bei abhebender Flamme und erhöhter CO-Bildung, sind die Öffnungen voll geöffnet. Die starke Rezirkulation verringert die Primärluftansaugung. Die Temperatur des Brennstabes steigt an. Mit steigenden Brennstabtemperaturen werden die Öffnungen hingegen zunächst teilweise und ab einer definierten Oberflächentemperatur ganz geschlossen. Die Primärluftansaugung steigt an und die Brennstabtemperatur fällt wieder ab.With bimetallic flaps, the flow cross-section of the openings can be changed continuously depending on the fuel rod temperature, which means that the recirculation and the primary air intake are also continuously changed. The openings are fully open at low fuel rod temperatures, ie when the flame is lifted and CO is increased. The strong recirculation reduces the primary air intake. The temperature of the fuel rod rises. With increasing fuel rod temperatures, on the other hand, the openings are initially partially closed and completely above a defined surface temperature. The primary air intake rises and the fuel rod temperature drops again.

Durch eine einfache Maßnahme einer mehr oder weniger starken Rezirkulation des Brenngas-Luft-Gemisches im Brennstab und Venturirohr ist somit die Brennstabtemperatur durch eine Beeinflussung der Primärluftansaugung genau auf das geeignete Maß einzustellen. Mängel durch zu hohe oder zu niedrige Temperaturen werden ausgeschlossen.By a simple measure of a more or less strong recirculation of the fuel gas-air mixture in the fuel rod and Venturi tube, the fuel rod temperature can thus be set exactly to the appropriate level by influencing the primary air intake. Defects caused by temperatures that are too high or too low are excluded.

Die Zeichnung stellt ein Ausführungsbeispiel der Erfindung dar. Es zeigt:

  • Fig. 1: Einen Längsschnitt durch einen Brennstab zur Andeutung des erfindungsgemäßen Prinzips,
  • Fig. 2: Einen Teil-Längsschnitt durch einen Brennstab,
  • Fig. 3: Den Schnitt A-A aus Fig. 2 und
  • Fig. 4: Die Draufsicht auf den Brennstab nach Fig. 2.
The drawing shows an embodiment of the invention. It shows:
  • 1: a longitudinal section through a fuel rod to indicate the principle of the invention,
  • 2: a partial longitudinal section through a fuel rod,
  • Fig. 3: The section AA from Fig. 2 and
  • FIG. 4: The top view of the fuel rod according to FIG. 2.

In einem Brennstab 1 ist ein Venturirohr 2 integriert. Das Gas G tritt aus einer Gasdüse in das Venturirohr 2 ein und saugt dabei die benötigte Primärluft P an. Nach einer Umlenkung am Ende des Venturirohres 2 strömt das Brenngas-Luft-Gemisch in den Ringraum 3 zwischen dem Venturirohr 2 und dem Brennstab 1. An der gelochten Brennstaboberfläche zündet es dann und wird dort verbrannt. Das Ansaugen der Primärluft P wird dadurch beeinflußt, daß ein Teilstrom des Gemisches durch Öffnungen 4 wieder in das Venturirohr 2 eintritt. Dieses Rezirkulieren wirkt sich auf die Menge der angesaugten Primärluft P aus. Die Rezirkulation ist durch temperaturabhängig verstellbare Bimetallklappen 5 zu verändern. Diese sind über einen Bügel 6 an der Innenwand des Brennstabes 1 befestigt. Sie können die Öffnung 4 bei hoher Brennstabtemperatur ganz freigeben (Fig. 3, links) oder bei niedriger Brennstabtemperatur ganz schließen (Fig. 3, rechts). Auch alle Zwischenstufen sind einzustellen.A venturi tube 2 is integrated in a fuel rod 1. The gas G enters the venturi tube 2 from a gas nozzle and thereby sucks in the required primary air P. After a deflection at the end of the venturi tube 2, the fuel gas / air mixture flows into the annular space 3 between the venturi tube 2 and the fuel rod 1. It then ignites at the perforated fuel rod surface and is burned there. The suction of the primary air P is influenced by the fact that a partial flow of the mixture re-enters the Venturi tube 2 through openings 4. This recirculation affects the amount of primary air P drawn in. The recirculation can be changed by means of bimetal flaps 5 which are adjustable as a function of temperature. These are attached to the inner wall of the fuel rod 1 via a bracket 6. You can fully open the opening 4 when the fuel rod temperature is high (Fig. 3, left) or close it completely at a low fuel rod temperature (Fig. 3, right). All intermediate levels must also be set.

Claims (1)

Bei einem hochvormischenden atmosphärischen Gasbrenner mit einem im Brennstab (1) integrierten Venturirohr (2) soll ohne äußere regeltechnische Maßnahmen die Zufuhr von Primärluft P zum Brenngas-Luft-Gemisch derart beeinflußt werden, daß sowohl ein Abheben der Flamme mit verstärkter CO-Bildung als auch ein Aufsitzen der Flamme mit verstärkter NOx-Bildung verhindert wird. Zu diesem Zweck sind in der Wand des Venturirohres (2) eine oder mehrere Öffnungen (5) für die Rezirkulation eines Teilstromes des Gemisches aus dem umgebenden Ringraum (4) des Brennstabes (1) in das Venturirohr (2) vorgesehen. Die Menge des rezirkulierenden Gemisches wirkt sich auf die Primärluftansaugung und damit auf das Brennergebnis aus.In a highly premixed atmospheric gas burner with a venturi tube (2) integrated in the fuel rod (1), the supply of primary air P to the fuel gas / air mixture is to be influenced without external control measures in such a way that the flame is lifted off with increased CO formation as well the flame is prevented from sitting on with increased NO x formation. For this purpose, one or more openings (5) are provided in the wall of the venturi tube (2) for the recirculation of a partial flow of the mixture from the surrounding annular space (4) of the fuel rod (1) into the venturi tube (2). The amount of the recirculating mixture affects the primary air intake and thus the firing result.
EP95710002A 1994-01-24 1995-01-21 Atmospheric gas burner Withdrawn EP0664420A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4401775A DE4401775C1 (en) 1994-01-24 1994-01-24 Gas burner with controlled recirculation
DE4401775 1994-01-24

Publications (1)

Publication Number Publication Date
EP0664420A1 true EP0664420A1 (en) 1995-07-26

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ID=6508431

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Application Number Title Priority Date Filing Date
EP95710002A Withdrawn EP0664420A1 (en) 1994-01-24 1995-01-21 Atmospheric gas burner

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EP (1) EP0664420A1 (en)
BE (1) BE1008519A6 (en)
DE (2) DE4401775C1 (en)
FR (1) FR2715459B3 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108506935A (en) * 2018-05-28 2018-09-07 杭州浙大天元科技有限公司 Based on the low NOx gas burners recycled in combustion gas and the method for reducing discharge

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE804027C (en) * 1949-04-13 1951-04-16 Johannes Becker Gas burners, especially for boiling kettles, ovens, stoves, etc.
DE3639974A1 (en) * 1986-11-22 1988-05-26 Stiebel Eltron Gmbh & Co Kg Burner lance
EP0284011A2 (en) * 1987-03-24 1988-09-28 BUDERUS HEIZTECHNIK GmbH Atmospheric gas burner

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT395764B (en) * 1991-03-12 1993-03-25 Vaillant Gmbh Premixing gas burner

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE804027C (en) * 1949-04-13 1951-04-16 Johannes Becker Gas burners, especially for boiling kettles, ovens, stoves, etc.
DE3639974A1 (en) * 1986-11-22 1988-05-26 Stiebel Eltron Gmbh & Co Kg Burner lance
EP0284011A2 (en) * 1987-03-24 1988-09-28 BUDERUS HEIZTECHNIK GmbH Atmospheric gas burner

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108506935A (en) * 2018-05-28 2018-09-07 杭州浙大天元科技有限公司 Based on the low NOx gas burners recycled in combustion gas and the method for reducing discharge

Also Published As

Publication number Publication date
FR2715459A3 (en) 1995-07-28
DE4401775C1 (en) 1995-06-01
BE1008519A6 (en) 1996-06-04
FR2715459B3 (en) 1995-12-22
DE19507693A1 (en) 1996-09-05

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