EP0284011A2 - Atmospheric gas burner - Google Patents

Atmospheric gas burner Download PDF

Info

Publication number
EP0284011A2
EP0284011A2 EP88104526A EP88104526A EP0284011A2 EP 0284011 A2 EP0284011 A2 EP 0284011A2 EP 88104526 A EP88104526 A EP 88104526A EP 88104526 A EP88104526 A EP 88104526A EP 0284011 A2 EP0284011 A2 EP 0284011A2
Authority
EP
European Patent Office
Prior art keywords
intake
atmospheric gas
gas burner
exhaust gas
gas
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Withdrawn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
EP88104526A
Other languages
German (de)
French (fr)
Other versions
EP0284011A3 (en
Inventor
Lothar Bechtum
Dieter Becker
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
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 Buderus Heiztechnik GmbH filed Critical Buderus Heiztechnik GmbH
Publication of EP0284011A2 publication Critical patent/EP0284011A2/en
Publication of EP0284011A3 publication Critical patent/EP0284011A3/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C9/00—Combustion apparatus characterised by arrangements for returning combustion products or flue gases to the combustion chamber
    • 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

Definitions

  • the invention relates to an atmospheric gas burner according to the preamble of claim 1.
  • a mixture of fuel and primary air is fed to the burner tube.
  • the combustion takes place after exiting the flow openings on the surface of the burner tube.
  • a very high temperature arises in the flame, with increasing nitrogen oxide formation as the temperature rises.
  • the oxygen partial pressure, the residence time of the reactants and the level of the flame temperature have an influence on the formation of nitrogen oxides.
  • the present invention uses the known effect of lowering the partial pressure of oxygen in the primary air by supplying exhaust gases.
  • a primary air mixture of fresh air and exhaust gas is fed to the burner tube. No separate fan is required for suction. Rather, this takes place through the injection effect of the gas jet. In this way, not only fresh air is drawn in, but also the required exhaust gas.
  • the negative pressure resulting from the primary and / or secondary air flow serves to suck in the exhaust gas.
  • the invention can be implemented in such a way that the supply duct for the primary air has a fixed or adjustable supply air opening and an exhaust gas inlet connection connected to the exhaust gas area and opens into the suction area of the gas jet.
  • the primary air is supplied through a duct in which the fresh air and the exhaust gases are mixed. Neither a separate suction device nor a separate exhaust system is required.
  • the fixed or adjustable supply air opening also allows the amount of fresh air to be adjusted to meet requirements.
  • the exhaust gas intake can be connected to the flow control, to the secondary heating surface and / or to the combustion chamber of the heating boiler.
  • a flap controlled by a motor or bimetal is to be used in front of or in the exhaust gas intake.
  • the suction takes place through the resulting negative pressure.
  • the additional control serves to set the flow more precisely.
  • a distributor plate connected upstream of the exhaust gas intake in the flow control also acts in the same sense.
  • the adjustable change in the supply air opening can also be regulated via a motor or bimetal-controlled flap in order to precisely adapt the fresh air supply to the existing requirements.
  • the fuel leaves the distributor pipe 1 with the fuel supply channel 1 a through a nozzle 2 in order to flow into the burner pipe 3.
  • the boiler is protected against heat loss by external insulation.
  • the supply duct 5 for the primary air opens into the inflow area of the fuel.
  • the primary air is drawn in as a mixture of fresh air and exhaust gases by means of an injection effect.
  • the fresh air flows through a supply air opening 5a with a controllable or controllable opening cross section.
  • the control is a motor or bimetallic flap 8a.
  • the exhaust gases are through exhaust gas intake 5b of the flow control 6 or the secondary heating surface of the boiler 7 (Fig. 1) or through an exhaust gas intake 5c from the combustion chamber (Fig. 2).
  • a motor-controlled or bimetallic flap 8b, c is to be used for regulation.
  • a distribution plate 9 in the flow safety device 6 has an additional influence on the flow.
  • the suction takes place through the injection effect of the fuel gas or through the resulting negative pressure.

Abstract

To reduce the oxygen partial pressure and thus to reduce the nitric oxide formation, waste gas is to be supplied to an atmospheric gas burner (waste gas recycling). This takes place in a common air channel (5) for the primary air with an adjustable or calibrated incoming air opening (5a) and with waste gas intakes (5b, 5c), which opens into the suction region of the fuel between burner nozzle (2) and burner pipe (3). <IMAGE>

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.

Dem Brennerrohr wird ein Gemisch aus Brennstoff und Primär­luft zugeführt. Die Verbrennung erfolgt nach dem Austritt aus den Strömungsöffnungen an der Oberfläche des Brenner­rohres. In der Flamme entsteht eine recht hohe Temperatur, wobei sich mit steigender Temperatur eine steigende Stick­oxidbildung ergibt. Auf die Bildung von Stickoxiden haben der Sauerstoffpartialdruck, die Verweilzeit der Reaktions­teilnehmer und die Höhe der Flammentemperatur einen Ein­fluß.A mixture of fuel and primary air is fed to the burner tube. The combustion takes place after exiting the flow openings on the surface of the burner tube. A very high temperature arises in the flame, with increasing nitrogen oxide formation as the temperature rises. The oxygen partial pressure, the residence time of the reactants and the level of the flame temperature have an influence on the formation of nitrogen oxides.

Eine Senkung des Sauerstoffpartialdruckes ist durch die Zufuhr Von Abgasen zur Primärluft möglich. Diese sogenannte Abgasrückführung wird bei Gebläsefeuerungen zur Stickoxid­minderung bereits eingesetzt ( vgl. DE-GM 85 16 607).Lowering the partial pressure of oxygen is possible by supplying exhaust gases to the primary air. This so-called exhaust gas recirculation is already used in fan fires for nitrogen oxide reduction (cf. DE-GM 85 16 607).

Die vorliegende Erfindung nutzt den bekannten Effekt einer Senkung des Sauerstoffpartialdruckes in der Primärluft durch Zufuhr von Abgasen.The present invention uses the known effect of lowering the partial pressure of oxygen in the primary air by supplying exhaust gases.

Bei atmosphärischen Gasbrennern liegen jedoch besondere Bedingungen vor, da hier kein Gebläse zum Ansaugen der Primärluft und somit auch der Abgase vorhanden ist. Ohne Zusatzmaßnahmen ist es nicht möglich, Abgase in den Luft­strom einzuleiten.
Es soll eine Möglichkeit geschaffen werden, der Primärluft ohne aufwendige bauliche Maßnahme die notwendige Abgasmenge zuzuführen.
Die Erfindung ist gekennzeichnet durch das im Kennzeichen des Patentanspruchs 1 genannte Merkmal.However, there are special conditions for atmospheric gas burners, since there is no fan to draw in the primary air and therefore also the exhaust gases. Without additional measures, it is not possible to introduce exhaust gases into the air flow.
A possibility is to be created to supply the primary air with the necessary amount of exhaust gas without complex structural measures.
The invention is characterized by the feature mentioned in the characterizing part of patent claim 1.

Dem Brennerrohr wird ein Primärluftgemisch aus Frischluft und Abgas zugeführt. Für das Ansaugen bedarf es keines separaten Gebläses. Dieses erfolgt vielmehr durch die Injek­tionswirkung des Gasstrahles. Auf diese Weise wird nicht nur Frischluft angesaugt, sondern gleichzeitig das benötigte Abgas. Dabei dient der aus der primär- und/oder sekundär­seitigen Luftströmung resultierende Unterdruck dem Ansaugen des Abgases.A primary air mixture of fresh air and exhaust gas is fed to the burner tube. No separate fan is required for suction. Rather, this takes place through the injection effect of the gas jet. In this way, not only fresh air is drawn in, but also the required exhaust gas. The negative pressure resulting from the primary and / or secondary air flow serves to suck in the exhaust gas.

Konstruktiv läßt sich die Erfindung so verwirklichen, daß der Zufuhrkanal für die Primärluft eine feste oder einstell­bare Zuluftöffnung und einen an den Abgasbereich ange­schlossenen Abgasansaugstutzen besitzt und in den Saugbe­reich des Gasstrahles mündet. Durch einen Kanal, in dem eine Mischung der Frischluft und der Abgase erfolgt, wird die Primärluft zugeführt. Dabei ist weder eine separate Saug­vorrichtung noch eine gesonderte Abgasführung erforderlich. Die feste oder einstellbare Zuluftöffnung erlaubt zudem eine Anpassung der Frischluftmenge an den Bedarf.In terms of construction, the invention can be implemented in such a way that the supply duct for the primary air has a fixed or adjustable supply air opening and an exhaust gas inlet connection connected to the exhaust gas area and opens into the suction area of the gas jet. The primary air is supplied through a duct in which the fresh air and the exhaust gases are mixed. Neither a separate suction device nor a separate exhaust system is required. The fixed or adjustable supply air opening also allows the amount of fresh air to be adjusted to meet requirements.

Es ist möglich, die Abgase an allen geeigneten Stellen der Feuerung zu entnehmen. Demgemäß kann der Abgasansaugstutzen an die Strömungssicherung, an die Nachschaltheizfläche und/­oder an den Feuerraum des Heizungskessels angeschlossen sein.It is possible to remove the exhaust gases at all suitable points in the furnace. Accordingly, the exhaust gas intake can be connected to the flow control, to the secondary heating surface and / or to the combustion chamber of the heating boiler.

Es hat sich als zweckmäßig erwiesen, den angesaugten Abgas­strom zusätzlich zu regeln. Zu diesem Zweck ist eine über eine motor- oder bimetallgesteuerte Klappe vor oder in dem Abgasansaugstutzen einzusetzen. Das Ansaugen erfolgt durch den entstehenden Unterdruck. Die zusätzliche Regelung dient einer genaueren Einstellung der Strömung. In demselben Sinne wirkt auch ein dem Abgasansaugstutzen in der Strömungs­sicherung vorgeschaltetes Verteilblech.
Auch die einstellbare Veränderung der Zuluftöffnung kann über eine motor- oder bimetallgesteuerte Klappe regelbar sein, um die Frischluftzufuhr den vorhandenen Bedürfnissen exakt an­zupassen.
Die beigefügte Zeichnung stellt ein Ausführungsbeispiel der Erfindung dar.It has proven to be expedient to additionally regulate the intake gas flow. For this purpose, a flap controlled by a motor or bimetal is to be used in front of or in the exhaust gas intake. The suction takes place through the resulting negative pressure. The additional control serves to set the flow more precisely. A distributor plate connected upstream of the exhaust gas intake in the flow control also acts in the same sense.
The adjustable change in the supply air opening can also be regulated via a motor or bimetal-controlled flap in order to precisely adapt the fresh air supply to the existing requirements.
The accompanying drawing represents an embodiment of the invention.

Es zeigt:

  • Fig. 1: Einen senkrechten Schnitt durch einen Heizungskessel mit dem zugehörenden Brenner- und Primärluftbereich und
  • Fig. 2: Ein vergrößertes Detail aus Fig. 1.
It shows:
  • Fig. 1: A vertical section through a boiler with the associated burner and primary air area and
  • FIG. 2: An enlarged detail from FIG. 1.

Der Brennstoff verläßt das Verteilerrohr 1 mit dem Brenn­stoffzufuhrkanal 1a durch eine Düse 2, um in das Brenner­rohr 3 einzuströmen. Gegen Wärmeverluste ist der Kessel durch eine äußere Isolierung geschützt.The fuel leaves the distributor pipe 1 with the fuel supply channel 1 a through a nozzle 2 in order to flow into the burner pipe 3. The boiler is protected against heat loss by external insulation.

Der Zufuhrkanal 5 für die Primärluft, mündet im Einströmbe­reich des Brennstoffes. Ein Ansaugen der Primärluft als einem Gemisch aus Frischluft und Abgasen erfolgt dabei durch Injektionswirkung. Die Frischluft strömt durch eine Zuluft­öffnung 5a mit regel- oder steuerbarem Öffnungsquerschnitt. Der Regelung dient dabei eine motor- oder bimetallgesteuerte Klappe 8a.
Die Abgase werden durch Abgasansaugstutzen 5b der Strömungs­sicherung 6 bzw. der Nachschaltheizfläche des Kessels 7 (Fig. 1) oder durch einen Abgasansaugstutzen 5c dem Feuerraum (Fig. 2) entnommen. Auch hier ist eine motor- ­oder bimetallgesteuerte Klappe 8b,c zur Regelung einzu­setzen. Ein Verteilblech 9 in der Strömungssicherung 6 bewirkt eine zusätzliche Strömungsbeeinflussung. Das Ansaugen erfolgt durch die Injektionswirkung des Brenn­gases bzw. durch den entstehenden Unterdruck.The supply duct 5 for the primary air opens into the inflow area of the fuel. The primary air is drawn in as a mixture of fresh air and exhaust gases by means of an injection effect. The fresh air flows through a supply air opening 5a with a controllable or controllable opening cross section. The control is a motor or bimetallic flap 8a.
The exhaust gases are through exhaust gas intake 5b of the flow control 6 or the secondary heating surface of the boiler 7 (Fig. 1) or through an exhaust gas intake 5c from the combustion chamber (Fig. 2). Here, too, a motor-controlled or bimetallic flap 8b, c is to be used for regulation. A distribution plate 9 in the flow safety device 6 has an additional influence on the flow. The suction takes place through the injection effect of the fuel gas or through the resulting negative pressure.

Claims (6)

1. Atmosphärischer Gasbrenner mit mindestens einem Brennerrohr (3), in das die benötigte Primärluft mit dem aus einer Düse 2) austretenden Gasstrahl einströmt, dadurch gekennzeichnet, daß die Primärluft durch einen in den Saugbereich des Gasstrahles mündenden Zufuhrkanal (5) mit einstellbarer oder kalibrierter Zuluftöffnung (5a) und an die Feuerung angeschlossenem Abgasansaugstutzen ( 5b, 5c) angesaugt wird.1. Atmospheric gas burner with at least one burner tube (3) into which the required primary air flows with the gas jet emerging from a nozzle 2), characterized in that the primary air through an inlet channel (5) opening into the suction region of the gas jet with adjustable or calibrated Supply air opening (5a) and the flue gas intake (5b, 5c) connected to the furnace. 2. Atmosphärischer Gasbrenner nach Anspruch 1, dadurch gekennzeichnet, daß der aus der primär- und/oder sekundärseitigen Luftströmung resultierende Unterdruck dem Ansaugen des Abgases aus der Feuerung dient.2. Atmospheric gas burner according to claim 1, characterized in that the negative pressure resulting from the primary and / or secondary air flow serves to suck in the exhaust gas from the furnace. 3. Atmosphärischer Gasbrenner nach Anspruch 1, dadurch gekennzeichnet, daß der Abgasansaugstutzen (5b,5c) wahlweise an die Strömungssicherung (6), an die Nachschalt­heizfläche und/oder an den Feuerraum eines Heizungskessels (7) angeschlossen ist.3. Atmospheric gas burner according to claim 1, characterized in that the exhaust gas intake (5b, 5c) is optionally connected to the flow control (6), to the secondary heating surface and / or to the combustion chamber of a heating boiler (7). 4. Atmosphärischer Gasbrenner nach den Ansprüchen 1 bis 3, dadurch gekennzeichnet, daß der angesaugte Abgasstrom über eine motor- oder bimetallgesteuerte Klappe (8b) vor oder in dem Abgasansaugstutzen (5b,c) geregelt wird.4. Atmospheric gas burner according to claims 1 to 3, characterized in that the intake gas flow is regulated via a motor or bimetallic valve (8b) in front of or in the exhaust gas intake (5b, c). 5. Atmosphärischer Gasbrenner nach den Ansprüchen 1 bis 3, dadurch gekennzeichnet, daß dem Abgasansaugstutzen (5b) in der Strömungssicherung (6) ein Verteilblech (9) vorgeschaltet ist.5. Atmospheric gas burner according to claims 1 to 3, characterized in that the exhaust gas intake (5b) in the flow control (6) is connected upstream of a distribution plate (9). 6. Atmosphärischer Gasbrenner nach Anspruch 1, dadurch gekennzeichnet, daß der angesaugte Zuluftstrom über eine motor- oder bimetallgesteuerte Klappe (8a) vor oder in der Zuluftöffnung (5a) geregelt wird.6. Atmospheric gas burner according to claim 1, characterized in that the intake air flow is regulated via a motor or bimetallic valve (8a) in front of or in the supply air opening (5a).
EP88104526A 1987-03-24 1988-03-22 Atmospheric gas burner Withdrawn EP0284011A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3709597 1987-03-24
DE19873709597 DE3709597A1 (en) 1987-03-24 1987-03-24 ATMOSPHERIC GAS BURNER

Publications (2)

Publication Number Publication Date
EP0284011A2 true EP0284011A2 (en) 1988-09-28
EP0284011A3 EP0284011A3 (en) 1988-11-30

Family

ID=6323836

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88104526A Withdrawn EP0284011A3 (en) 1987-03-24 1988-03-22 Atmospheric gas burner

Country Status (2)

Country Link
EP (1) EP0284011A3 (en)
DE (1) DE3709597A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992008927A1 (en) * 1990-11-19 1992-05-29 Exxon Chemical Patents Inc. Flue gas recirculation for nox reduction in premix burners
EP0664420A1 (en) * 1994-01-24 1995-07-26 Buderus Heiztechnik GmbH Atmospheric gas burner
US6247917B1 (en) * 1998-08-21 2001-06-19 Texaco Inc. Flue gas recirculation system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH677965A5 (en) * 1988-09-02 1991-07-15 Strebelwerk Ag

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1609150A (en) * 1926-02-08 1926-11-30 Oil Devices Corp Control device for heating combustible mixtures
GB1418867A (en) * 1971-10-25 1975-12-24 Imp Metal Ind Kynoch Ltd Gas-fired appliance
JPS6080011A (en) * 1983-10-11 1985-05-07 Matsushita Electric Ind Co Ltd Liquid fuel combustion apparatus
DE8520263U1 (en) * 1985-07-11 1985-12-05 Joh. Vaillant Gmbh U. Co, 5630 Remscheid Continuous or storage water heater

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1609150A (en) * 1926-02-08 1926-11-30 Oil Devices Corp Control device for heating combustible mixtures
GB1418867A (en) * 1971-10-25 1975-12-24 Imp Metal Ind Kynoch Ltd Gas-fired appliance
JPS6080011A (en) * 1983-10-11 1985-05-07 Matsushita Electric Ind Co Ltd Liquid fuel combustion apparatus
DE8520263U1 (en) * 1985-07-11 1985-12-05 Joh. Vaillant Gmbh U. Co, 5630 Remscheid Continuous or storage water heater

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Band 9, Nr. 223 (M-411)[1946], 10. September 1985; & JP-A-60 080 011 (MATSUSHITA DENKI SANGYO K.K.) 07-05-1985 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992008927A1 (en) * 1990-11-19 1992-05-29 Exxon Chemical Patents Inc. Flue gas recirculation for nox reduction in premix burners
AU654986B2 (en) * 1990-11-19 1994-12-01 Exxon Chemical Patents Inc. Flue gas recirculation for NOx reduction in premix burners
EP0664420A1 (en) * 1994-01-24 1995-07-26 Buderus Heiztechnik GmbH Atmospheric gas burner
US6247917B1 (en) * 1998-08-21 2001-06-19 Texaco Inc. Flue gas recirculation system

Also Published As

Publication number Publication date
DE3709597A1 (en) 1988-10-06
EP0284011A3 (en) 1988-11-30

Similar Documents

Publication Publication Date Title
DE60108711T2 (en) Premix burner with low NOx emissions and method therefor
DE2660865C3 (en) Combustion device for carrying out a two-stage combustion with exhaust gas recirculation
DE2602401A1 (en) BURNERS FOR LIQUID AND GASEOUS FUELS
DE2653404A1 (en) PROCESS AND BURNER FOR BURNING LIQUID FUEL, IN PARTICULAR OIL
EP0062854A1 (en) Gas-fired water or air heater
EP0284011A2 (en) Atmospheric gas burner
DE3738622C1 (en) Heating furnace with equipment for recirculating flue gas
AT393888B (en) PRE-MIXED GAS BURNER
EP0261303B1 (en) Pressure-charged fluidized-bed combustion apparatus
AT413004B (en) METHOD FOR CONTROLLING A BOILER HEATED BY A FAN SUPPORTED BURNER
DE606215C (en) Heater
DE4237719C2 (en) Atmospheric gas burner
DE2737902C2 (en)
DE955668C (en) Firing for drying systems
EP4023938B1 (en) Burner arrangement for a pre-mix burner
DE4311009A1 (en) Method and arrangement for supplying burn-out air to the flue gas stream of a steam boiler fired by coal dust
AT221696B (en) Pressure control device in a ceramic recuperator for preheating the combustion air for an industrial furnace
DE851391C (en) Firing for the combustion of dust-like fuels for steam-air-thermal power plants
DE19920113A1 (en) Method and device for heating up a furnace zone containing contaminated waste gases with residual oxygen content applies hot gases generated by fuel combustion to the waste gases
DE892044C (en) Fire cabinet, preferably for flame tube boilers
CH654899A5 (en) Wood gas burner which can be added onto a heating boiler
DE721279C (en) Control device for the main fuel valve of heaters which are heated with gaseous or liquid fuels and to which the air flow required for combustion or an air flow to be heated is supplied under pressure or suction
AT216712B (en) Gas heater
DE679350C (en) Safety device for electrically controlled gas-heated devices
DE3625402A1 (en) Device for regulating the gas/air mixture in a gas-heated boiler

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE CH DE FR GB IT LI NL

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE CH DE FR GB IT LI NL

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19890531