EP3767175A1 - Procédé et dispositif de réglage de la sensibilité d'un détecteur permettant de surveiller une flamme dans un appareil chauffant - Google Patents

Procédé et dispositif de réglage de la sensibilité d'un détecteur permettant de surveiller une flamme dans un appareil chauffant Download PDF

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Publication number
EP3767175A1
EP3767175A1 EP20185200.1A EP20185200A EP3767175A1 EP 3767175 A1 EP3767175 A1 EP 3767175A1 EP 20185200 A EP20185200 A EP 20185200A EP 3767175 A1 EP3767175 A1 EP 3767175A1
Authority
EP
European Patent Office
Prior art keywords
alternating voltage
flame
voltage pulses
length
pulses
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.)
Pending
Application number
EP20185200.1A
Other languages
German (de)
English (en)
Inventor
Jochen Grabe
Stefan Hucke
Tobias Funke
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.)
Vaillant GmbH
Original Assignee
Vaillant 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 Vaillant GmbH filed Critical Vaillant GmbH
Publication of EP3767175A1 publication Critical patent/EP3767175A1/fr
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
    • F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
    • F23N5/123—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23M—CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
    • F23M11/00—Safety arrangements
    • F23M11/04—Means for supervising combustion, e.g. windows
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/20—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays
    • F23N5/203—Systems for controlling combustion with a time programme acting through electrical means, e.g. using time-delay relays using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2223/00—Signal processing; Details thereof
    • F23N2223/18—Chopper
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2223/00—Signal processing; Details thereof
    • F23N2223/42—Function generator
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2229/00—Flame sensors
    • F23N2229/12—Flame sensors with flame rectification current detecting means

Definitions

  • the invention is in the field of regulating or monitoring a combustion process in a heating device, in particular a burner for preparing hot water or heating a building.
  • a heating device in particular a burner for preparing hot water or heating a building.
  • an ionization measurement is carried out in a flame area, especially in many heating devices. Such measurements should enable stable regulation over long periods of time.
  • flame monitoring is typically carried out in heating devices, the main task of which is to ensure that no fuel gas is supplied after the heating device has been started if there is no flame. This prevents the formation of a potentially explosive mixture and the escape of unburned fuel gas.
  • An electronic flame monitor that is often used uses an ignition electrode that is already present, which is otherwise not required for any other purpose after a flame has been ignited, to generate an ionization signal which is used to monitor the flame.
  • the specially prepared ionization signal can not only reliably detect the presence of a flame or its extinction, but also measure, for example, the physical lifting of the flame from the burner due to excessive air supply at an early stage. In this way, it can be switched off early if the flame becomes unstable.
  • ionization electrode an ignition or ionization electrode
  • This current or a voltage signal derived therefrom, called ionization signal in the following, are measured and, if necessary after digitization, further processed in an analog / digital converter for flame monitoring.
  • an AC voltage source with a high output resistance has hitherto been used, which initially supplies an AC voltage without a DC voltage component to the ionization electrode and the counter electrode (ground).
  • the present invention is intended to provide a remedy here in order to enable safe and reliable operation of a heater with qualitatively and / or quantitatively precise flame monitoring with little expenditure on equipment and at low cost.
  • the method according to the invention for adapting the sensitivity of a detector for monitoring a flame in a heating device is characterized in that an alternating voltage source generates individual alternating voltage pulses of a predeterminable alternating voltage frequency and a predeterminable length between an ionization electrode located in a flame area and a counter electrode, with a time interval lies between the start of the individual AC voltage pulses, and wherein the length and / or the spacing of the individual AC voltage pulses can be adjusted.
  • an effective amplitude of the alternating voltage can be set, which allows a simpler and, above all, more cost-effective design than when using a conventional alternating voltage source with adjustable amplitude.
  • the desired accuracy of flame monitoring does not depend on whether the alternating voltage is sinusoidal and continuous or not. It is only important that the effective amplitude, i.e. the integral of the individual amplitudes, can be reproducibly set over a certain period of time and that the integral of positive and negative half-waves is essentially constant over time, i.e. negative and positive half-waves occur approximately equally.
  • the shape of the alternating voltage pulses does not matter, so that individual pulses z. B. may have decreasing amplitudes. With the shape and length of the individual alternating voltage pulses remaining the same, the effective amplitude of the alternating voltage, which only affects the ionization signal, can be adjusted by setting the time interval between the alternating voltage pulses. In this way, the sensitivity of the measurement can be adjusted during operation.
  • the alternating voltage frequency is preferably higher than a repetition frequency resulting from the time interval between the alternating voltage pulses, in particular greater than 1 kilohertz [kHz]. Frequencies in the kilohertz range can be generated with smaller transformers than lower frequencies, which makes smaller electronic circuits possible.
  • the alternating voltage frequency is greater than 15 kHz.
  • pulses can be generated which contain several successive waves, possibly decaying in their amplitude, and which can be repeated at suitable time intervals.
  • Suitable distances arise in particular with a repetition frequency between 0.2 and 15 kHz.
  • the effective amplitude (voltage) of the alternating voltage can be set over a wide range with these values.
  • the maximum amplitude of the alternating voltage pulses is between 50 and 300 volts [V], preferably between 100 and 200 V.
  • Each alternating voltage pulse should preferably have essentially no direct voltage component so that the rectifying effect of the flame can be easily measured and evaluated. Any small DC voltage component that may be present should in any case be constant so that it can be compensated if necessary.
  • each alternating voltage pulse has an amplitude that decreases along its length.
  • z. B on the principle of a so-called "flyback converter” can be used.
  • a simple microcontroller can then be used to easily set the effective amplitude by varying the time intervals between the alternating voltage pulses.
  • the so-called pulse duty factor resulting from the length of the pulses and the time interval is used to set a desired effective amplitude of the alternating voltage, so that the sensitivity of the measurement can be adapted to operating conditions.
  • the AC voltage source is preferably designed for frequencies greater than 15 kHz and AC voltage pulses of constant length while the time interval between the AC voltage pulses can be adjusted.
  • the time interval between the start of two consecutive alternating voltage pulses can be set between 0.005 and 5 milliseconds [ms], preferably between 0.05 and 1 ms.
  • the invention also relates to a computer program product, comprising commands which cause the heating device to carry out the described method with the described device.
  • FIG. 1 shows schematically an embodiment of a device proposed here.
  • a flame area 2 forms during operation.
  • Air enters the heater 1 via an air supply 3 and a fan 5.
  • Combustion gas is mixed with the air via a combustion gas supply 4 and a combustion gas valve 6.
  • An ignition electrode 7 ignites the mixture at the start of the combustion process and is then z. B. used as part of a flame monitor 11.
  • an ionization electrode 8 is typically used to measure an ionization signal in the flame region 2, which is used to control the lambda value when the heater is in operation.
  • a control unit 10, which regulates the fan 5 and / or fuel gas valve 6 accordingly, is used for this purpose.
  • a flame monitor 11, with which the present invention is concerned, ensures that fuel gas is only supplied when a stable flame is detected.
  • a further ionization electrode usually the ignition electrode 7 can be used for this purpose, is used to generate a further ionization signal, its electronic processing is specially designed for the task of flame monitoring.
  • an alternating voltage source 12 is specially designed for this purpose.
  • Fig. 2 shows schematically an exemplary embodiment for a circuit such as can be used for flame monitoring.
  • An AC voltage source 12 with a high output resistance 13 initially supplies an AC voltage, essentially without a DC voltage component, to the ignition electrode 7 and the counter electrode 9 (ground).
  • the voltage only drops in a half-wave due to the rectifying effect of the flame (shown as a diode in the equivalent circuit diagram), so that an alternating voltage is also present at the input of evaluation electronics 14 (amplifier and converter) a negative DC voltage component is present, which becomes the desired ionization signal in the evaluation electronics 14 and can be converted in an analog / digital converter 15 and then processed further.
  • This entire arrangement forms a detector for flame monitoring, which only supplies an ionization signal when a flame is present, the ionization signal also having a typical profile from which, for example, the incipient physical lift-off of the flames from gas outlet openings can be recognized, so that a shutdown can also occur with the onset of instability due to a gas velocity that is too high or a lambda value that is too high.
  • the sensitivity of the detector depends on the amplitude of the alternating voltage used, which is why this is generally adjustable in its amplitude in the prior art, for example between 50 and 200 V at a frequency of 200 Hz, for example.
  • an alternating voltage source 12 which has an alternating voltage pulse generator 17, a microcontroller 18 and an adjuster 19.
  • This structure creates an inexpensive and space-saving alternating voltage source 12 in which an effective amplitude can be set according to the desired sensitivity of the detector.
  • An effective amplitude does not have the form of a typical approximately sinusoidal alternating voltage, but leads to the same ionization signals during further processing as a sinusoidal alternating voltage with this amplitude.
  • FIG. 3 illustrates qualitatively what happens in the process of setting the effective amplitude according to the invention.
  • the upper part of FIG. 4 shows how a sinusoidal alternating voltage of the amplitude U1 changes when the amplitude is reduced to a value U2.
  • the voltage U is plotted against time t in the diagram.
  • Fig. 2 shows how the effective amplitude of an alternating voltage formed from individual alternating voltage pulses 13 of length L can be adjusted by changing the distance T between the individual alternating voltage pulses 13. At a distance T1, the effective amplitude is greater than at a greater distance T2. If the maximum amplitude Umax of the individual alternating voltage pulses 13 is suitably selected, possibly also their frequency F1, an effective amplitude corresponding to that in the upper part of FIG Fig. 3 sinusoidal alternating voltages shown can be set.
  • the invention thus enables an alternative, cost-effective design for an adjustable AC voltage source in a detector for flame monitoring in a heating device.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • Control Of Combustion (AREA)
EP20185200.1A 2019-07-16 2020-07-10 Procédé et dispositif de réglage de la sensibilité d'un détecteur permettant de surveiller une flamme dans un appareil chauffant Pending EP3767175A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102019119206.4A DE102019119206A1 (de) 2019-07-16 2019-07-16 Verfahren und Vorrichtung zur Anpassung der Empfindlichkeit eines Detektors zur Überwachung einer Flamme in einem Heizgerät

Publications (1)

Publication Number Publication Date
EP3767175A1 true EP3767175A1 (fr) 2021-01-20

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP20185200.1A Pending EP3767175A1 (fr) 2019-07-16 2020-07-10 Procédé et dispositif de réglage de la sensibilité d'un détecteur permettant de surveiller une flamme dans un appareil chauffant

Country Status (3)

Country Link
EP (1) EP3767175A1 (fr)
CN (1) CN112240564A (fr)
DE (1) DE102019119206A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113253031A (zh) * 2021-05-19 2021-08-13 广东电网有限责任公司 一种输电线路山火跳闸试验平台
WO2023217327A1 (fr) * 2022-05-11 2023-11-16 Viessmann Climate Solutions Se Procédé pour faire fonctionner un ensemble brûleur

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994028354A1 (fr) * 1993-05-28 1994-12-08 Honeywell Inc. Capteur du redressement d'une flamme employant l'excitation pulsee
EP1519114A1 (fr) * 2003-09-26 2005-03-30 Betronic Design B.V. Système de surveillance de flamme
US20060257804A1 (en) * 2005-05-12 2006-11-16 Honeywell International Inc. Dynamic dc biasing and leakage compensation

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102007018122B4 (de) * 2007-04-16 2013-10-17 Viessmann Werke Gmbh & Co Kg Flammenüberwachungsvorrichtung mit einer Spannungserzeugungs- und Messanordnung und Verfahren zum Überwachen eines Brenners mittels der Flammenüberwachungsvorrichtung
DE102013009119A1 (de) * 2013-05-29 2014-12-04 Kübler Gmbh Verfahren zur Steuerung einer Heizungsanlage mit einer Vielzahl von Dunkelstrahler-Einheiten sowie Anordnung zur Durchführung des Verfahrens

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994028354A1 (fr) * 1993-05-28 1994-12-08 Honeywell Inc. Capteur du redressement d'une flamme employant l'excitation pulsee
EP1519114A1 (fr) * 2003-09-26 2005-03-30 Betronic Design B.V. Système de surveillance de flamme
US20060257804A1 (en) * 2005-05-12 2006-11-16 Honeywell International Inc. Dynamic dc biasing and leakage compensation

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113253031A (zh) * 2021-05-19 2021-08-13 广东电网有限责任公司 一种输电线路山火跳闸试验平台
WO2023217327A1 (fr) * 2022-05-11 2023-11-16 Viessmann Climate Solutions Se Procédé pour faire fonctionner un ensemble brûleur

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DE102019119206A1 (de) 2021-01-21
CN112240564A (zh) 2021-01-19

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