EP2357410B1 - Method and burner with flame detection based on ionisation flow measurement - Google Patents

Method and burner with flame detection based on ionisation flow measurement Download PDF

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Publication number
EP2357410B1
EP2357410B1 EP11152479.9A EP11152479A EP2357410B1 EP 2357410 B1 EP2357410 B1 EP 2357410B1 EP 11152479 A EP11152479 A EP 11152479A EP 2357410 B1 EP2357410 B1 EP 2357410B1
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EP
European Patent Office
Prior art keywords
voltage
burner
operating state
measuring
flame
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EP11152479.9A
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German (de)
French (fr)
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EP2357410A2 (en
EP2357410A3 (en
Inventor
Werner John
Martin Ries
Wolfgang Hesse
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Viessmann Werke GmbH and Co KG
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Viessmann Werke GmbH and Co KG
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Priority to PL11152479T priority Critical patent/PL2357410T3/en
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Publication of EP2357410A3 publication Critical patent/EP2357410A3/en
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    • 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
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2227/00—Ignition or checking
    • F23N2227/02—Starting or ignition cycles
    • 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
    • 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

Definitions

  • the invention relates to a method for ionization current based flame detection with a flame monitoring system in a burner, and a burner with a flame monitoring system.
  • flame monitoring systems are often used, which exploit the rectifier effect of the flame, which therefore operate according to the so-called ionization principle.
  • an alternating voltage is applied between two electrodes.
  • the instantaneous performance of the burner is determined by the volume that fills the flame.
  • the magnitude of the DC component therefore gives a measure of the intensity of the flame, the absence of a zero intensity flame corresponding to the detection of which must be detected reliably and promptly in order to prevent the escape of unburned gas into the burner chamber.
  • Known flame monitoring systems generally have a voltage generating unit for generating an ignition voltage for operating an ignition device of a burner and / or for generating a measuring voltage of an ionisation electrode for monitoring a flame of the burner and a measuring unit for measuring an ionization current generated by the measuring voltage.
  • the flame monitoring system may include a voltage generating unit for generating an ignition voltage for operating an igniter of a burner and a separate voltage generating unit for generating a measurement voltage of an ionization electrode Monitoring a flame of the burner have.
  • the flame monitoring system usually comprises a control unit for controlling the voltage generating unit and for evaluating measured values of the measuring unit.
  • a flame monitoring system in which a voltage generating unit is capable of generating both an ignition voltage and a measuring voltage, wherein the voltage generated by the voltage generating unit can be changed by a controlling monitoring device.
  • the voltage generating unit is designed so that the voltage generated serves as the ignition voltage when the generated voltage exceeds a Zündschwelldepth, and as a measuring voltage when the generated voltage is below the Zündschwelldepth.
  • the flame monitoring system additionally has the property that the voltage generated by the voltage generating unit can be varied via a pulse width modulated signal transmitted from the monitoring device to the voltage generating unit. This allows, for example, to reliably detect signs of wear, short circuits or bending of the ignition electrode by passing through a predetermined ignition sequence in a test mode.
  • the saturation voltage is in the range between 80 and 120 volts.
  • a method of ionization current based flame detection with a flame monitoring system in a burner having a first operating state representing a start phase of the burner and a second operating state representing a modulation operation of the burner According to the method, a first measurement voltage greater than a saturation voltage is generated to generate a first ionization current at an ionization electrode of the flame monitoring system in the first operating state of the burner and a second measurement voltage which is less than the saturation voltage to generate a second ionization current the ionization electrode of the flame monitoring system generates in the second operating state of the burner, wherein the first measurement voltage and the second measurement voltage generated by a device for generating a measurement voltage of the flame monitoring system, which is adapted to the generated measurement voltage in a voltage range, which consists of at least one voltage value above the saturation voltage and at least one voltage value below the saturation voltage is to vary, and wherein the device for generating the measurement voltage, the generated measurement voltage from the first Meßspa Change to the second measurement voltage
  • the burner Due to the ability of the device for generating a measuring voltage to vary the measuring voltage in a voltage range which consists of at least one voltage value above a saturation voltage and at least one voltage value below the saturation voltage, it is advantageously possible by means of the present method, in different operating states the burner always in the range of the best resolution, ie to operate during a start-up phase of the burner above the saturation limit (saturation voltage) and during a modulating operation of the burner below the saturation limit.
  • saturation limit saturation voltage
  • the flame monitoring system during the start-up phase of the burner and during the modulation operation of the burner always achieve optimum resolution. This means that, on the one hand, the flame can be reliably detected during the starting phase, but at the same time, surprisingly, an exact evaluation of the flame characteristics and the quality of the combustion process is possible in the modulation mode of the burner.
  • the arrangement according to the invention allows the transition between the first and second operating state of the burner and the change from the first to the second measuring voltage generated by the device for generating the measuring voltage to be matched to one another in an advantageous manner. Due to the surprising interaction between the transition from the first to the second operating state of the burner and the change from the first to the second measuring voltage, the occurrence of errors, such as a too late detection of the flame in the starting phase or an insufficient evaluation of the flame characteristics in the modulation mode, such they can occur due to incorrect selection of the measuring voltage can be effectively avoided.
  • the saturation voltage is preferably greater than 80 volts and less than 120 volts. Preferably, the saturation voltage is 100 volts.
  • the flame detection system preferably has a measuring unit which is electrically connected to the ionization electrode and detects the ionization current generated by the device for generating the measuring voltage.
  • the measuring unit detects the first ionization current in the first operating state of the burner and the second ionization current in the second operating state of the burner.
  • an air-fuel ratio of the burner in the modulation mode of the burner as a function of the second ionization current detected by the measuring unit.
  • the measuring unit preferably changes from a first measuring range to a second measuring range when the device for generating the measuring voltage changes the generated measuring voltage from the first measuring voltage to the second measuring voltage. Because of this property, both the first ionization current produced by the first measurement voltage and the second ionization current produced by the second measurement voltage, which is lower than the first ionization current, can be detected and evaluated.
  • the flame detection may further comprise a step of comparing at least one threshold value and the ionization current detected by the measuring unit.
  • the comparison of the ionization current detected by the measuring unit with at least one threshold value serves, for example, in the starting phase of the burner for the reliable detection of a flame.
  • the flame is detected when the ionization current is above a predetermined threshold, for example.
  • the flame monitoring system can be monitored for defects such as faulty ignition, gas supply interruption, or ionization electrode failure thresholds.
  • the control unit for controlling the voltage generation unit is designed to compare an ionization current detected by the measuring unit with at least one predetermined upper and / or lower threshold value and to generate an error signal if the ionization current exceeds the upper threshold value or falls below the lower threshold value.
  • the error signal can be used as a warning signal to the operator and / or to generate an emergency shutdown of the burner. Furthermore, a use of the error signal to trigger a correction, or readjustment, the quality of combustion is conceivable.
  • the at least one threshold value is preferably redetermined since the provision of the second measurement voltage, which according to the invention is less than the first measurement voltage, also generates the generated ionization current is lower.
  • the at least one threshold value is determined anew by keeping a ratio formed from the at least one threshold value and a flame resistance constant.
  • the flame resistance can be determined from the respectively generated measurement voltage and the respective detected ionization current.
  • the ionization current detected by the measuring unit can be normalized to the flame resistance and a comparison of the normalized ionization current with a constant threshold value based on the at least one threshold value can be carried out.
  • the burner preferably changes from the first operating state to the second operating state in response to an operating state signal of a control unit for controlling the flame monitoring system.
  • the operating state signal of the control unit for controlling the flame monitoring system may be a pulse width modulated signal.
  • the operating state signal of the control unit for controlling the flame monitoring system is preferably transmitted from the control unit to the device for generating the measuring voltage and the measuring unit.
  • the operating state signal of the control unit for controlling the flame monitoring system is transmitted with a control signal to the device for generating the measuring voltage and the measuring voltage is modulated so that it has information about the operating state of the burner.
  • the device for generating the measurement voltage preferably changes the measurement voltage from the first measurement voltage to the second measurement voltage in response to the operating state signal of the control unit.
  • a safety time between a start of the burner and the switching to the second operating state is further adjustable. In this way it can be ensured that the transition to the second operating state takes place only when the flame has stabilized.
  • a burner having a flame monitoring system comprising an ionization electrode and a measurement voltage generating means for ionization current detection based flame detection.
  • the burner has a first operating state, which represents a start phase of the burner, and a second operating state, which represents a modulation operation of the burner.
  • the measurement voltage generating device includes means for generating a first measurement voltage that is greater than a saturation voltage, for generating a first ionization current at an ionization electrode of the flame monitoring system in the first operating state of the burner, and for generating a second measurement voltage that is less than the saturation voltage for generating a second ionization current at the ionization electrode of the flame monitoring system in the second operating state of the burner, wherein the device for generating the measurement voltage is adapted to the generated measurement voltage in a voltage range, which consists of at least one voltage value above the saturation voltage and at least one voltage value below the saturation voltage is to vary, and wherein the device for generating the measurement voltage changes the generated measurement voltage from the first measurement voltage to the second measurement voltage when the burner changes from the first operating state to the second operating state.
  • the device for generating a measuring voltage preferably has means for determining an operating state of the burner.
  • the means for determining the operating state of the burner is preferably the operating state of the burner in response to an operating condition signal of a control unit for controlling the flame monitoring system of the burner determinable.
  • the means for generating the measurement voltage further comprises means for detecting a change in the operating state of the burner, and changes the generated measurement voltage in response to a detected change in the operating state of the burner.
  • Fig. 2 schematically shows a flame monitoring system for monitoring a burner 22 with a voltage generating and measuring arrangement 10 according to the preferred embodiment.
  • the voltage generating and measuring arrangement 10 comprises a device 12 for generating a measuring voltage (voltage generating unit).
  • This voltage generating unit 12 is adapted to vary the voltage (measurement voltage) generated by it in a voltage range which extends from a voltage value below a saturation voltage to a voltage value above the saturation voltage.
  • the measurement voltage generated by the voltage generation unit 12 is applied to an ionization electrode as an ionization voltage.
  • the saturation voltage is preferably greater than 80 volts and less than 120 volts. Preferably, the saturation voltage is 100 volts.
  • a control unit 24 serves to monitor a flame 18 of the burner 22.
  • the voltage generating and measuring arrangement 10 comprises a measuring unit 20 for measuring an ionization current generated by the measuring voltage.
  • the measuring voltage is an alternating voltage which drops across the flame 18 of the burner 22.
  • the flame 18 is preferably a gas flame and has a rectifying property, since there are 18 carriers of different polarities in the flame, the mobility of which differs greatly.
  • the ionization current from or to the ionization electrode 16 flows predominantly during a half-period of the measurement voltage, during which the latter has a certain sign.
  • the ionization current also comes to a standstill, which can be measured by the measuring unit 20. If this happens, appropriate safety measures can be taken, for example, the gas supply can be switched off.
  • the evaluation of the signals of the measuring unit and the control of the voltage generating unit 12 takes place in the control unit 24 of the flame monitoring device.
  • the control unit 24 controls the voltage generation unit 12 by means of a first, preferably pulse-width-modulated control signal 26a, which is transmitted via a first signal line 28a from the control unit 24 to the voltage generation unit 12.
  • the control unit 24 transmits a second, preferably pulse-width-modulated control signal 26b to the measuring unit 20 via a second signal line 28b.
  • the first and second control signals may optionally have a different modulation type.
  • the second control signal 26b is primarily used to specify a measuring frequency, but can also be used to control operating parameters of the measuring unit 20.
  • the control unit 24 receives a first dynamic feedback 30a from the voltage generating unit 12 of the voltage generating and measuring arrangement 10. Via a fourth signal line 28d, the control unit 24 receives a second dynamic feedback 30b from the measuring unit 20.
  • the first dynamic feedback 30a and the second dynamic feedback 30b are each preferably pulse width modulated signals, wherein a duty cycle of the first dynamic feedback 30a and the second dynamic feedback 30b has a continuous range of values and is time-dependent.
  • the value of the duty cycle encodes an actually generated voltage in the voltage generating unit 12 or an ionization current measured by the measuring unit 20.
  • a first measuring voltage 12a is generated by the device 12 for generating a measuring voltage, which is greater than the saturation voltage and at the ionization 16 causes a first DC component or first ionization 16a.
  • the first measurement voltage 12a and the first ionization current 16a are then detected by the measuring unit 20. If the first ionization current 16a is greater than a predetermined threshold, the flame 18 is detected by the control unit 24 for controlling the flame monitoring system.
  • an operating condition signal is sent by the control unit 24 to the measurement voltage generating means 12 for changing the generated measurement voltage from the first measurement voltage 12a to a second measurement voltage 12b provided and there is also a switchover from the first operating state to a second operating state or a modulating operation of the burner 22 in response to the operating state signal.
  • the second measuring voltage 12b is smaller than the saturation voltage.
  • the second measuring voltage 12b is generated by the device 12 for generating a measuring voltage, which causes a second direct current component or second ionization current 16b at the ionization electrode 16.
  • the second measurement voltage 12b and the second ionization current 16b are detected by the measurement unit 20.
  • the control unit 24 is designed to compare the second ionization current 16b detected by the measuring unit 20 with at least one predetermined upper and / or lower threshold value and to generate an error signal if the measured value exceeds the upper threshold value or falls below the lower threshold value.
  • the control unit 24 may also perform a correction of the combustion quality based on the comparison of the ionization current 16b with the upper threshold and / or the lower threshold.
  • the control unit 24 is configured to convert the second ionization current 16b into a flame condition signal, on the basis of which an evaluation of the flame characteristics and the flame quality can take place.
  • Fig. 3 shows a flowchart of the method for varying the measurement voltage of the device for generating the measurement voltage for ionization current-based flame detection of the burner 22 with the subsequent steps.
  • step S10 the first measurement voltage 12a for generating the first ionization current 16a is generated at the ionization electrode 16 of the flame monitoring system in the first operating state of the burner 22 by the measuring voltage generating means 12, the first operating state of the burner 22 being the start phase of the burner 22 ,
  • step S 20 the first measuring voltage 12a provided by the voltage generating unit for generating the measuring voltage and the first ionizing current 16a are detected by the measuring unit 20.
  • step S30 If the ionization current 16a is greater than the predetermined threshold, the process proceeds to step S30. If the ionization current 16a is smaller than the predetermined threshold, the process returns to step S10.
  • step S30 due to the fact that the ionization current is greater than the predetermined threshold, the flame 18 is detected by the control unit 24 for controlling the flame monitoring system. Thereupon, an operating condition signal is provided by the control unit 24 to the measuring voltage generating means 12, which includes a command code for changing the measuring voltage from the first measuring voltage 12a to the second measuring voltage 12b. At the same time, in response to the operating state signal, the transition of the burner from the first operating state to the second operating state takes place.
  • step S40 in response to the operating state signal of the control unit 24, the second measuring voltage 12b for generating the second ionizing current 16b is generated at the ionization electrode 16 of the flame monitoring system in the second operating state of the burner 22 by the measuring voltage generating means 12.
  • step S 50 the second measuring voltage 12 b provided by the voltage generating unit 12 for generating the measuring voltage and the second ionizing current 16 b are detected by the measuring unit 20.
  • the device 12 for generating the measuring voltage may comprise means for determining the operating state of the burner, by means of which the operating state of the burner can be determined by evaluating a signal of the control unit 24, and further means for detecting a change in the operating state of the burner, for example from the first operating state in the second operating state.
  • step S30 in FIG Fig. 3 possible transition from the first operating state of the burner to the second operating state is in Fig. 4 shown. It will be apparent to those skilled in the art that some of the sub-steps described below are associated with Fig. 3 described steps are readily combinable.
  • step S31 a determination is made of the operating state of the burner by the means for determining the operating state. This determination can take place by evaluating an operating state signal of the control unit 24.
  • step S32 the means for detecting a change in the operating state of the burner applied in the measuring voltage generating device 12 checks whether the operating state of the burner is in response to a control signal of the control unit 24 from the first operating state to the second operating state has changed.
  • step S33 a check is made in step S33 as to whether the second safety time has expired, otherwise the procedure continues directly with step S34. If the second safety time is provided and has expired, the process continues to step S34, otherwise it returns to step S33.
  • step S34 the voltage generated by the measuring voltage generating device 12 is changed from the first measuring voltage 12a to the second measuring voltage 12b.
  • the measuring range of the measuring unit 20 is changed from a first measuring range to a second measuring range, and possibly existing threshold values are redetermined.

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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)

Description

Die Erfindung betrifft ein Verfahren zur auf lonisationsstrommessung basierenden Flammenerkennung mit einem Flammenüberwachungssystem in einem Brenner, sowie einen Brenner mit einem Flammenüberwachungssystem.The invention relates to a method for ionization current based flame detection with a flame monitoring system in a burner, and a burner with a flame monitoring system.

Stand der TechnikState of the art

Zur Überwachung von Gasflammen werden häufig Flammenüberwachungssysteme eingesetzt, die die Gleichrichterwirkung der Flamme ausnutzen, die also nach dem sogenannten Ionisationsprinzip arbeiten. Dabei wird zwischen zwei Elektroden eine Wechselspannung angelegt. Die momentane Leistung des Brenners wird durch das Volumen, das die Flamme ausfüllt, bestimmt. Die Höhe des Gleichstromanteils gibt daher ein Maß für die Intensität der Flamme, wobei das Nichtvorhandensein einer Flamme der Intensität Null entspricht, deren Detektion zuverlässig und zeitnah festgestellt werden muss, um ein Ausströmen von unverbranntem Gas in den Brennerraum zu vermeiden.For monitoring gas flames flame monitoring systems are often used, which exploit the rectifier effect of the flame, which therefore operate according to the so-called ionization principle. In this case, an alternating voltage is applied between two electrodes. The instantaneous performance of the burner is determined by the volume that fills the flame. The magnitude of the DC component therefore gives a measure of the intensity of the flame, the absence of a zero intensity flame corresponding to the detection of which must be detected reliably and promptly in order to prevent the escape of unburned gas into the burner chamber.

Bekannte Flammenüberwachungssysteme weisen in der Regel eine Spannungserzeugungseinheit zum Erzeugen einer Zündspannung zum Betreiben einer Zündvorrichtung eines Brenners und/oder zum Erzeugen einer Messspannung einer lonisationselektrode zum Überwachen einer Flamme des Brenners und eine Messeinheit zum Messen eines durch die Messspannung erzeugten lonisationsstroms auf. Das Flammenüberwachungssystem kann alternativ auch eine Spannungserzeugungseinheit zum Erzeugen einer Zündspannung zum Betreiben einer Zündvorrichtung eines Brenners und eine separate Spannungserzeugungseinheit zum Erzeugen einer Messspannung einer Ionisationselektrode zum Überwachen einer Flamme des Brenners aufweisen. Ferner umfasst das Flammenüberwachungssystem in der Regel eine Steuereinheit zum Steuern der Spannungserzeugungseinheit und zum Auswerten von Messwerten der Messeinheit.Known flame monitoring systems generally have a voltage generating unit for generating an ignition voltage for operating an ignition device of a burner and / or for generating a measuring voltage of an ionisation electrode for monitoring a flame of the burner and a measuring unit for measuring an ionization current generated by the measuring voltage. Alternatively, the flame monitoring system may include a voltage generating unit for generating an ignition voltage for operating an igniter of a burner and a separate voltage generating unit for generating a measurement voltage of an ionization electrode Monitoring a flame of the burner have. Furthermore, the flame monitoring system usually comprises a control unit for controlling the voltage generating unit and for evaluating measured values of the measuring unit.

Beispielsweise wird in der DE 10 2007 018 122 A1 ein Flammenüberwachungssystem beschrieben, bei dem eine Spannungserzeugungseinheit in der Lage ist, sowohl eine Zündspannung als auch eine Messspannung zu erzeugen, wobei die von der Spannungserzeugungseinheit erzeugte Spannung von einer steuernden Überwachungseinrichtung verändert werden kann. Hierbei ist die Spannungserzeugungseinheit so ausgelegt, dass die erzeugte Spannung als Zündspannung dient, wenn die erzeugte Spannung eine Zündschwellspannung überschreitet, und als Messspannung, wenn die erzeugte Spannung die Zündschwellspannung unterschreitet.For example, in the DE 10 2007 018 122 A1 a flame monitoring system is described in which a voltage generating unit is capable of generating both an ignition voltage and a measuring voltage, wherein the voltage generated by the voltage generating unit can be changed by a controlling monitoring device. Here, the voltage generating unit is designed so that the voltage generated serves as the ignition voltage when the generated voltage exceeds a Zündschwellspannung, and as a measuring voltage when the generated voltage is below the Zündschwellspannung.

Durch Erfassung einer tatsächlich an einer Zündelektrode oder an einer lonisationselektrode anliegenden Spannung durch eine Messvorrichtung wird es ermöglicht, Fehlfunktionen der Zündelektrode oder der lonisationselektrode zu detektieren. Das Flammenüberwachungssystem hat zusätzlich die Eigenschaft, dass die von der Spannungserzeugungseinheit erzeugte Spannung über ein von der Überwachungseinrichtung an die Spannungserzeugungseinheit übertragenes pulsweitenmoduliertes Signal variiert werden kann. Dies erlaubt, beispielsweise durch Durchlaufen einer vorgegebenen Zündfolge in einem Testbetrieb, Verschleißerscheinungen, Kurzschlüsse oder ein Verbiegen der Zündelektrode zuverlässig zu erkennen.By detecting a voltage actually applied to an ignition electrode or an ionization electrode by a measuring device, it is possible to detect malfunctions of the ignition electrode or the ionization electrode. The flame monitoring system additionally has the property that the voltage generated by the voltage generating unit can be varied via a pulse width modulated signal transmitted from the monitoring device to the voltage generating unit. This allows, for example, to reliably detect signs of wear, short circuits or bending of the ignition electrode by passing through a predetermined ignition sequence in a test mode.

Bei einer auf lonisationsstrommessung basierenden Flammenerkennung treten bei Messspannungen oberhalb einer Sättigungsspannung Messungenauigkeiten auf, da eine Variation der Messspannung bei Spannungen oberhalb der Sättigungsspannung zu Sättigungseffekten führt. Diese beeinflussen die Messgenauigkeit negativ, da die zu messende Änderung des Flammenwiderstands im Sättigungsbereich keine lineare Änderung des lonisationsstroms bewirkt (siehe Fig. 1). Typischerweise liegt die Sättigungsspannung hierbei im Bereich zwischen 80 und 120 Volt.In the case of a flame detection based on ionization current measurement, measurement inaccuracies occur at measurement voltages above a saturation voltage, since a variation of the measurement voltage at voltages above the saturation voltage leads to saturation effects. These negatively affect the measuring accuracy, since the change in the flame resistance to be measured in the saturation region does not cause a linear change in the ionization current (see Fig. 1 ). Typically, the saturation voltage is in the range between 80 and 120 volts.

Aus diesem Grund wird bei verbrennungsgeregelten Systemen, bei denen eine hohe Messgenauigkeit erzielt werden muss, mit Spannungen unterhalb der Sättigungsgrenze gearbeitet, bei denen der lonisationsstrom im Wesentlichen durch Ladungsträgerrekombination bestimmt wird und somit eine Veränderung des Flammenwiderstands bei gleicher Messspannung eine messbare Änderung des lonisationsstroms bewirkt.For this reason, in combustion-controlled systems in which a high measurement accuracy must be achieved, working with voltages below the saturation limit, in which the ionization current is essentially determined by charge carrier recombination and thus causes a change in the flame resistance at the same measurement voltage causes a measurable change in the ionization.

Es ist jedoch ebenfalls bekannt, dass beim Brennerstart verschiedene andere nichtlineare Effekte eine Messung des lonisationsstroms unterhalb der Sättigungsgrenze erschweren. So beeinflussen z.B. die Brennertemperatur, die Elektrodenbeschaffenheit und andere Einflussgrößen eine sichere Flammenerkennung. Aus diesem Grund arbeiten Flammenüberwachungssysteme, die nicht zur Verbrennungsregelung benötigt werden und gegebenenfalls nur binär erfassen müssen, ob eine Flamme existiert oder nicht, in der Regel oberhalb der obengenannten Sättigungsgrenze.However, it is also known that at burner start various other non-linear effects make it difficult to measure the ionization current below the saturation limit. Thus, e.g. the burner temperature, the electrode characteristics and other influencing variables ensure reliable flame detection. For this reason, flame monitoring systems which are not required for combustion control and, if necessary, only have to detect in binary whether a flame exists or not, generally operate above the aforementioned saturation limit.

Zusammenfassung der ErfindungSummary of the invention

Es ist daher die Aufgabe der vorliegenden Erfindung, ein Verfahren und eine Vorrichtung zu schaffen, bei welchen sowohl in einem ersten Betriebszustand, der einer Startphase, als auch in einem zweiten Betriebszustand des Brenners, der einem Modulations- beziehungsweise Regelbetrieb entspricht, eine auf lonisationsstrommessung basierende Flammenerkennung mit einfachen Mitteln realisiert werden kann.It is therefore the object of the present invention to provide a method and a device in which both in a first operating state, the start phase, as well as in a second operating state of the burner, which corresponds to a modulation or control operation, based on ionisationsstrommessung Flame detection can be realized with simple means.

Diese Aufgabe wird durch ein Verfahren mit den Merkmalen des Anspruchs 1, eine Vorrichtung mit den Merkmalen des Anspruchs 13 und ein System mit den Merkmalen des Anspruchs 16 gelöst. Weitere vorteilhafte Ausgestaltungen der Erfindung sind in den Unteransprüchen wiedergegeben.This object is achieved by a method having the features of claim 1, a device having the features of claim 13 and a system having the features of claim 16. Further advantageous embodiments of the invention are given in the dependent claims.

Entsprechend einer bevorzugten Ausführungsform wird ein Verfahren zur auf lonisationsstrommessung basierenden Flammenerkennung mit einem Flammenüberwachungssystem in einem Brenner mit einem ersten Betriebszustand, welcher eine Startphase des Brenners darstellt und einem zweiten Betriebszustand, welcher einen Modulationsbetrieb des Brenners darstellt, vorgesehen. Gemäß dem Verfahren wird eine erste Messspannung, welche größer als eine Sättigungsspannung ist, zum Erzeugen eines ersten lonisationsstroms an einer lonisationselektrode des Flammenüberwachungssystems in dem ersten Betriebszustand des Brenners erzeugt und eine zweite Messspannung, welche kleiner als die Sättigungsspannung ist, zum Erzeugen eines zweiten Ionisationsstroms an der Ionisationselektrode des Flammenüberwachungssystems in dem zweiten Betriebszustand des Brenners erzeugt, wobei die erste Messspannung und die zweite Messspannung von einer Vorrichtung zum Erzeugen einer Messspannung des Flammenüberwachungssystems erzeugt werden, die dazu geeignet ist, die erzeugte Messspannung in einem Spannungsbereich, welcher aus zumindest einem Spannungswert oberhalb der Sättigungsspannung und zumindest einem Spannungswert unterhalb der Sättigungsspannung besteht, zu variieren, und wobei die Vorrichtung zum Erzeugen der Messspannung die erzeugte Messspannung von der ersten Messspannung zu der zweiten Messspannung ändert, wenn der Brenner von dem ersten Betriebszustand in den zweiten Betriebszustand wechselt.According to a preferred embodiment, there is provided a method of ionization current based flame detection with a flame monitoring system in a burner having a first operating state representing a start phase of the burner and a second operating state representing a modulation operation of the burner. According to the method, a first measurement voltage greater than a saturation voltage is generated to generate a first ionization current at an ionization electrode of the flame monitoring system in the first operating state of the burner and a second measurement voltage which is less than the saturation voltage to generate a second ionization current the ionization electrode of the flame monitoring system generates in the second operating state of the burner, wherein the first measurement voltage and the second measurement voltage generated by a device for generating a measurement voltage of the flame monitoring system, which is adapted to the generated measurement voltage in a voltage range, which consists of at least one voltage value above the saturation voltage and at least one voltage value below the saturation voltage is to vary, and wherein the device for generating the measurement voltage, the generated measurement voltage from the first Meßspa Change to the second measurement voltage changes when the burner from the first operating state to the second operating state.

Durch die Fähigkeit der Vorrichtung zum Erzeugen einer Messspannung, die Messspannung in einem Spannungsbereich, welcher aus zumindest einem Spannungswert oberhalb einer Sättigungsspannung und zumindest einem Spannungswert unterhalb der Sättigungsspannung besteht, zu variieren, ist es mittels des vorliegenden Verfahrens in vorteilhafter Weise möglich, in verschiedenen Betriebszuständen des Brenners stets im Bereich der besten Auflösung, d.h. während einer Startphase des Brenners oberhalb der Sättigungsgrenze (Sättigungsspannung) und während eines modulierenden Betriebs des Brenners unterhalb der Sättigungsgrenze zu arbeiten. Somit kann das Flammenüberwachungssystem während der Startphase des Brenners und während des Modulationsbetriebs des Brenners stets eine optimale Auflösung erzielen. Das heißt, dass einerseits die Flamme während der Startphase zuverlässig erkannt werden kann, zugleich aber überraschenderweise im Modulationsbetrieb des Brenners eine exakte Bewertung der Flammeneigenschaften und der Qualität des Verbrennungsvorgangs möglich ist.Due to the ability of the device for generating a measuring voltage to vary the measuring voltage in a voltage range which consists of at least one voltage value above a saturation voltage and at least one voltage value below the saturation voltage, it is advantageously possible by means of the present method, in different operating states the burner always in the range of the best resolution, ie to operate during a start-up phase of the burner above the saturation limit (saturation voltage) and during a modulating operation of the burner below the saturation limit. Thus, the flame monitoring system during the start-up phase of the burner and during the modulation operation of the burner always achieve optimum resolution. This means that, on the one hand, the flame can be reliably detected during the starting phase, but at the same time, surprisingly, an exact evaluation of the flame characteristics and the quality of the combustion process is possible in the modulation mode of the burner.

Zugleich können durch die erfindungsgemäße Anordnung der Übergang zwischen dem ersten und zweiten Betriebszustand des Brenners und das Ändern von der ersten zur zweiten von der Vorrichtung zum Erzeugen der Messspannung erzeugten Messspannung in vorteilhafter Weise aufeinander abgestimmt werden. Durch das Überraschende Zusammenwirken zwischen dem Übergang von dem ersten zum zweiten Betriebszustand des Brenners und dem Ändern von der ersten zur zweiten Messspannung kann das Auftreten von Fehlern, wie ein zu spätes Erkennen der Flamme in der Startphase oder eine unzureichende Bewertung der Flammeneigenschaften im Modulationsbetrieb, wie sie aufgrund falscher Wahl der Messspannung auftreten können, wirksam vermieden werden.At the same time, the arrangement according to the invention allows the transition between the first and second operating state of the burner and the change from the first to the second measuring voltage generated by the device for generating the measuring voltage to be matched to one another in an advantageous manner. Due to the surprising interaction between the transition from the first to the second operating state of the burner and the change from the first to the second measuring voltage, the occurrence of errors, such as a too late detection of the flame in the starting phase or an insufficient evaluation of the flame characteristics in the modulation mode, such they can occur due to incorrect selection of the measuring voltage can be effectively avoided.

Die Sättigungsspannung ist hierbei vorzugsweise größer als 80 Volt und kleiner als 120 Volt. Vorzugsweise beträgt die Sättigungsspannung 100 Volt.The saturation voltage is preferably greater than 80 volts and less than 120 volts. Preferably, the saturation voltage is 100 volts.

Das Flammenerfassungssystem weist vorzugsweise eine mit der Ionisationselektrode elektrisch verbundene Messeinheit auf, die den von der Vorrichtung zum Erzeugen der Messspannung erzeugten Ionisationsstrom erfasst. Die Messeinheit erfasst den ersten Ionisationsstrom im ersten Betriebszustand des Brenners und den zweiten Ionisationsstrom im zweiten Betriebszustand des Brenners. Durch das Erfassen der verschiedenen Ionisationsströme kann im ersten Betriebszustand des Brenners die Flamme zuverlässig erkannt werden, während im zweiten Betriebszustand des Brenners eine exakte Bewertung der Flammeneigenschaften durchgeführt werden kann.The flame detection system preferably has a measuring unit which is electrically connected to the ionization electrode and detects the ionization current generated by the device for generating the measuring voltage. The measuring unit detects the first ionization current in the first operating state of the burner and the second ionization current in the second operating state of the burner. By detecting the different ionization currents, the flame can be reliably detected in the first operating state of the burner, while in the second operating state of the burner an exact evaluation of the flame characteristics can be performed.

Vorzugsweise wird ein Luft-Brennstoff-Verhältnis des Brenners im Modulationsbetrieb des Brenners in Abhängigkeit des von der Messeinheit erfassten zweiten lonisationsstroms geregelt. Dadurch wird eine genaue Erfassung der Flammeneigenschaften und entsprechend eine bedarfsorientierte Regelung der Verbrennungsverhältnisse ermöglicht.Preferably, an air-fuel ratio of the burner in the modulation mode of the burner as a function of the second ionization current detected by the measuring unit. As a result, an accurate detection of the flame characteristics and according to a demand-oriented control of the combustion conditions is made possible.

Die Messeinheit wechselt vorzugsweise von einem ersten Messbereich zu einem zweiten Messbereich, wenn die Vorrichtung zum Erzeugen der Messspannung die erzeugte Messspannung von der ersten Messspannung zu der zweiten Messspannung ändert. Aufgrund dieser Eigenschaft kann sowohl der von der ersten Messspannung hervorgerufene erste Ionisationsstrom als auch der von der zweiten Messspannung hervorgerufene zweite lonisationsstrom, welcher geringer ist als der erste lonisationsstrom, erfasst und ausgewertet werden.The measuring unit preferably changes from a first measuring range to a second measuring range when the device for generating the measuring voltage changes the generated measuring voltage from the first measuring voltage to the second measuring voltage. Because of this property, both the first ionization current produced by the first measurement voltage and the second ionization current produced by the second measurement voltage, which is lower than the first ionization current, can be detected and evaluated.

Die Flammenerkennung kann ferner einen Schritt Vergleichen zumindest eines Schwellwerts und des von der Messeinheit erfassten lonisationsstroms aufweisen. Das Vergleichen des von der Messeinheit erfassten Ionisationsstroms mit zumindest einem Schwellwert dient z.B. in der Startphase des Brenners dem zuverlässigen Erkennen einer Flamme. Hierbei wird die Flamme dann erkannt, wenn der Ionisationsstrom beispielsweise über einem vorbestimmten Schwellwert liegt. Darüber hinaus kann das Flammenüberwachungssystem mittels Schwellwerten auf Defekte wie beispielsweise eine fehlerhafte Zündung, eine Unterbrechung der Gaszufuhr oder einen Fehler der lonisationselektrode überwacht werden. Die Steuereinheit zum Steuern der Spannungserzeugungseinheit ist dazu ausgelegt, einen von der Messeinheit erfassten Ionisationsstrom mit wenigstens einem vorgegebenen oberen und/oder unteren Schwellwert zu vergleichen und ein Fehlersignal zu erzeugen, wenn der lonisationsstrom den oberen Schwellwert übertrifft oder den unteren Schwellwert unterschreitet. Dadurch kann für einen Bediener in einer einfachen Weise erkennbar gemacht werden, dass die Betriebskenngrößen des Flammenüberwachungssystems einen durch den oberen Schwellwert und/oder den unteren Schwellwert begrenzten Normalbereich verlassen haben. Das Fehlersignal kann als Warnsignal an den Bediener und/oder zum Erzeugen einer Notabschaltung des Brenners benutzt werden. Ferner ist eine Benutzung des Fehlersignals zum Auslösen einer Korrektur, beziehungsweise Nachregelung, der Verbrennungsgüte denkbar. Bei dem Ändern der erzeugten Messspannung durch die Vorrichtung zum Erzeugen der Messspannung von der ersten Messspannung zu der zweiten Messspannung wird vorzugsweise der zumindest eine Schwellwert neu bestimmt, da bei Vorsehen der zweiten Messspannung, welche erfindungsgemäß geringer ist als die erste Messspannung, der erzeugte lonisationsstrom ebenfalls geringer ist.The flame detection may further comprise a step of comparing at least one threshold value and the ionization current detected by the measuring unit. The comparison of the ionization current detected by the measuring unit with at least one threshold value serves, for example, in the starting phase of the burner for the reliable detection of a flame. In this case, the flame is detected when the ionization current is above a predetermined threshold, for example. In addition, the flame monitoring system can be monitored for defects such as faulty ignition, gas supply interruption, or ionization electrode failure thresholds. The control unit for controlling the voltage generation unit is designed to compare an ionization current detected by the measuring unit with at least one predetermined upper and / or lower threshold value and to generate an error signal if the ionization current exceeds the upper threshold value or falls below the lower threshold value. As a result, it can be recognized to an operator in a simple manner that the operating parameters of the flame monitoring system have left a normal range limited by the upper threshold value and / or the lower threshold value. The error signal can be used as a warning signal to the operator and / or to generate an emergency shutdown of the burner. Furthermore, a use of the error signal to trigger a correction, or readjustment, the quality of combustion is conceivable. When changing the generated measurement voltage by the device for generating the measurement voltage from the first measurement voltage to the second measurement voltage, the at least one threshold value is preferably redetermined since the provision of the second measurement voltage, which according to the invention is less than the first measurement voltage, also generates the generated ionization current is lower.

Vorteilhafterweise wird der zumindest eine Schwellwert dadurch neu bestimmt, dass ein aus dem zumindest einen Schwellwert und einem Flammenwiderstand gebildetes Verhältnis konstant gehalten wird. Hierbei kann der Flammenwiderstand aus der jeweils erzeugten Messspannung und dem jeweils erfassten lonisationsstrom bestimmt werden. Alternativ kann der von der Messeinheit erfasste lonisationsstrom auf den Flammenwiderstand normiert werden und ein Vergleich des normierten Ionisationsstroms mit einem auf dem zumindest einen Schwellwert basierenden konstanten Schwellwert erfolgen.Advantageously, the at least one threshold value is determined anew by keeping a ratio formed from the at least one threshold value and a flame resistance constant. In this case, the flame resistance can be determined from the respectively generated measurement voltage and the respective detected ionization current. Alternatively, the ionization current detected by the measuring unit can be normalized to the flame resistance and a comparison of the normalized ionization current with a constant threshold value based on the at least one threshold value can be carried out.

Der Brenner wechselt von dem ersten Betriebszustand in den zweiten Betriebszustand vorzugsweise in Reaktion auf ein Betriebszustandssignal einer Steuereinheit zum Steuern des Flammenüberwachungssystems. Das Betriebszustandssignal der Steuereinheit zum Steuern des Flammenüberwachungssystems kann ein pulsweitenmoduliertes Signal sein. Das Betriebszustandssignal der Steuereinheit zum Steuern des Flammenüberwachungssystems wird vorzugsweise von der Steuereinheit an die Vorrichtung zum Erzeugen der Messspannung und die Messeinheit übertragen. Das Betriebszustandssignal der Steuereinheit zum Steuern des Flammenüberwachungssystems wird mit einem Steuersignal an die Vorrichtung zum Erzeugen der Messspannung übertragen und die Messspannung wird derart moduliert, dass diese eine Information über den Betriebszustand des Brenners aufweist. Somit kann eine Umschaltung von dem ersten Betriebszustand des Brenners in den zweiten Betriebszustand des Brenners erfolgen, sobald das Vorhandensein einer Flamme von der Steuereinheit zum Steuern des Flammenüberwachungssystems erkannt wird.The burner preferably changes from the first operating state to the second operating state in response to an operating state signal of a control unit for controlling the flame monitoring system. The operating state signal of the control unit for controlling the flame monitoring system may be a pulse width modulated signal. The operating state signal of the control unit for controlling the flame monitoring system is preferably transmitted from the control unit to the device for generating the measuring voltage and the measuring unit. The operating state signal of the control unit for controlling the flame monitoring system is transmitted with a control signal to the device for generating the measuring voltage and the measuring voltage is modulated so that it has information about the operating state of the burner. Thus, a switchover from the first operating state of the burner to the second operating state of the burner can take place as soon as the presence of a flame is detected by the control unit for controlling the flame monitoring system.

Vorzugsweise ändert die Vorrichtung zum Erzeugen der Messspannung die Messspannung von der ersten Messspannung zur zweiten Messspannung in Reaktion auf das Betriebszustandssignal der Steuereinheit. Durch das gemeinsam - beziehungsweise synchron - gesteuerte Umschalten des Betriebszustandes und der erzeugten Messspannung wird eine überraschende Verzahnung zwischen dem Übergang des Brenners vom ersten Betriebszustand in den zweiten Betriebszustand und dem Ändern der Messspannung von der ersten Messspannung zur zweiten Messspannung erzielt. Hierdurch können in vorteilhafter Weise Fehler bei der Flammenerkennung beim Übergang vom ersten Betriebszustand in den zweiten Betriebszustand vermieden werden.The device for generating the measurement voltage preferably changes the measurement voltage from the first measurement voltage to the second measurement voltage in response to the operating state signal of the control unit. By the common - or synchronously - controlled switching of the operating state and the generated measuring voltage, a surprising interlocking between the transition of the burner from the first operating state to the second operating state and changing the measuring voltage from the first measuring voltage to the second measuring voltage is achieved. As a result, errors in the flame detection during the transition from the first operating state to the second operating state can be avoided in an advantageous manner.

Vorzugsweise ist ferner eine Sicherheitszeit zwischen einem Start des Brenners und dem Umschalten in den zweiten Betriebszustand einstellbar. Hierdurch kann sichergestellt werden, dass der Übergang in den zweiten Betriebszustand erst dann erfolgt, wenn sich die Flamme stabilisiert hat.Preferably, a safety time between a start of the burner and the switching to the second operating state is further adjustable. In this way it can be ensured that the transition to the second operating state takes place only when the flame has stabilized.

Entsprechend der bevorzugten Ausführungsform der vorliegenden Erfindung wird des Weiteren ein Brenner mit einem Flammenüberwachungssystem das eine lonisationselektrode und eine Vorrichtung zum Erzeugen einer Messspannung zur auf lonisationsstrommessung basierenden Flammenerkennung aufweist, vorgesehen. Der Brenner weist einen ersten Betriebszustand, welcher eine Startphase des Brenners darstellt und einen zweiten Betriebszustand, welcher einen Modulationsbetrieb des Brenners darstellt, auf. Die Vorrichtung zum Erzeugen einer Messspannung enthält Mittel zum Erzeugen einer ersten Messspannung, welche größer als eine Sättigungsspannung ist, zum Erzeugen eines ersten lonisationsstroms an einer Ionisationselektrode des Flammenüberwachungssystems in dem ersten Betriebszustand des Brenners und zum Erzeugen einer zweiten Messspannung, welche kleiner als die Sättigungsspannung ist, zum Erzeugen eines zweiten Ionisationsstroms an der lonisationselektrode des Flammenüberwachungssystems in dem zweiten Betriebszustand des Brenners, wobei die Vorrichtung zum Erzeugen der Messspannung dazu geeignet ist, die erzeugte Messspannung in einem Spannungsbereich, welcher aus zumindest einen Spannungswert oberhalb der Sättigungsspannung und zumindest einen Spannungswert unterhalb der Sättigungsspannung besteht, zu variieren, und wobei die Vorrichtung zum Erzeugen der Messspannung die erzeugte Messspannung von der ersten Messspannung zu der zweiten Messspannung ändert, wenn der Brenner von dem ersten Betriebszustand in den zweiten Betriebszustand wechselt. Die Vorrichtung zum Erzeugen einer Messspannung weist vorzugsweise Mittel zum Bestimmen eines Betriebszustands des Brenners auf. Durch die Mittel zum Bestimmen des Betriebszustands des Brenners ist vorzugsweise der Betriebszustand des Brenners in Reaktion auf ein Betriebszustandssignal einer Steuereinheit zum Steuern des Flammenüberwachungssystems des Brenners bestimmbar. Vorteilhafterweise weist die Vorrichtung zum Erzeugen der Messspannung ferner Mittel zum Erkennen einer Änderung des Betriebszustandes des Brenners auf, und ändert die erzeugte Messspannung in Reaktion auf eine erkannte Änderung des Betriebszustandes des Brenners.According to the preferred embodiment of the present invention, there is further provided a burner having a flame monitoring system comprising an ionization electrode and a measurement voltage generating means for ionization current detection based flame detection. The burner has a first operating state, which represents a start phase of the burner, and a second operating state, which represents a modulation operation of the burner. The measurement voltage generating device includes means for generating a first measurement voltage that is greater than a saturation voltage, for generating a first ionization current at an ionization electrode of the flame monitoring system in the first operating state of the burner, and for generating a second measurement voltage that is less than the saturation voltage for generating a second ionization current at the ionization electrode of the flame monitoring system in the second operating state of the burner, wherein the device for generating the measurement voltage is adapted to the generated measurement voltage in a voltage range, which consists of at least one voltage value above the saturation voltage and at least one voltage value below the saturation voltage is to vary, and wherein the device for generating the measurement voltage changes the generated measurement voltage from the first measurement voltage to the second measurement voltage when the burner changes from the first operating state to the second operating state. The device for generating a measuring voltage preferably has means for determining an operating state of the burner. By the means for determining the operating state of the burner is preferably the operating state of the burner in response to an operating condition signal of a control unit for controlling the flame monitoring system of the burner determinable. Advantageously, the means for generating the measurement voltage further comprises means for detecting a change in the operating state of the burner, and changes the generated measurement voltage in response to a detected change in the operating state of the burner.

Kurze Beschreibung der ZeichnungShort description of the drawing

Ausführungsbeispiele, aus denen sich weitere erfinderische Merkmale ergeben können, auf die die Erfindung aber in ihrem Umfang nicht beschränkt ist, sind in den Zeichnungen dargelegt. Es zeigt schematisch:

  • Fig. 1 ein Diagramm eines Ionisationsstroms in Funktion einer Messspannung entsprechend dem Stand der Technik;
  • Fig. 2 ein Flammenüberwachungssystem mit einer Spannungserzeugungs- und Messanordnung entsprechend einer bevorzugten Ausführungsform der vorliegenden Erfindung;
  • Fig. 3 ein Ablaufdiagramm des Verfahrens zur auf Ionisationsstrommessung basierenden Flammenerkennung mit einem Flammenüberwachungssystem in einem Brenner entsprechend einer bevorzugten Ausführungsform der vorliegenden Erfindung;
  • Fig. 4 ein Ablaufdiagramm eines alternativen Schritts des Verfahrens zur auf lonisationsstrommessung basierenden Flammenerkennung mit einem Flammenüberwachungssystem in einem Brenner entsprechend einer weiteren bevorzugten Ausführungsform der vorliegenden Erfindung;
Embodiments from which further inventive features may result, but to which the invention is not limited in scope, are set forth in the drawings. It shows schematically:
  • Fig. 1 a diagram of an ionization current in function of a measurement voltage according to the prior art;
  • Fig. 2 a flame monitoring system having a voltage generating and measuring arrangement according to a preferred embodiment of the present invention;
  • Fig. 3 a flowchart of the method for Ionisationsstrommessung based flame detection with a flame monitoring system in a burner according to a preferred embodiment of the present invention;
  • Fig. 4 a flowchart of an alternative step of the process for ionization current based flame detection with a flame monitoring system in a burner according to another preferred embodiment of the present invention;

Ausführliche Beschreibung der ErfindungDetailed description of the invention

Fig. 2 zeigt schematisch ein Flammenüberwachungssystem zum Überwachen eines Brenners 22 mit einer Spannungserzeugungs- und Messanordnung 10 entsprechend der bevorzugten Ausführungsform. Die Spannungserzeugungs-und Messanordnung 10 umfasst eine Vorrichtung 12 zum Erzeugen einer Messspannung (Spannungserzeugungseinheit). Diese Spannungserzeugungseinheit 12 ist geeignet, die von ihr erzeugte Spannung (Messspannung) in einem Spannungsbereich, welcher sich von einem Spannungswert unterhalb einer Sättigungsspannung bis zu einem Spannungswert oberhalb der Sättigungsspannung erstreckt, zu variieren. Die von der Spannungserzeugungseinheit 12 erzeugte Messspannung liegt als eine Ionisationsspannung an einer Ionisationselektrode an. Die Sättigungsspannung ist vorzugsweise größer als 80 Volt und kleiner als 120 Volt. Vorzugsweise beträgt die Sättigungsspannung 100 Volt. Eine Steuereinheit 24 dient zum Überwachen einer Flamme 18 des Brenners 22. Des Weiteren umfasst die Spannungserzeugungs- und Messanordnung 10 eine Messeinheit 20 zum Messen eines durch die Messspannung erzeugten Ionisationsstroms. Die Messspannung ist eine Wechselspannung, die über der Flamme 18 des Brenners 22 abfällt. Fig. 2 schematically shows a flame monitoring system for monitoring a burner 22 with a voltage generating and measuring arrangement 10 according to the preferred embodiment. The voltage generating and measuring arrangement 10 comprises a device 12 for generating a measuring voltage (voltage generating unit). This voltage generating unit 12 is adapted to vary the voltage (measurement voltage) generated by it in a voltage range which extends from a voltage value below a saturation voltage to a voltage value above the saturation voltage. The measurement voltage generated by the voltage generation unit 12 is applied to an ionization electrode as an ionization voltage. The saturation voltage is preferably greater than 80 volts and less than 120 volts. Preferably, the saturation voltage is 100 volts. A control unit 24 serves to monitor a flame 18 of the burner 22. Furthermore, the voltage generating and measuring arrangement 10 comprises a measuring unit 20 for measuring an ionization current generated by the measuring voltage. The measuring voltage is an alternating voltage which drops across the flame 18 of the burner 22.

Die Flamme 18 ist vorzugsweise eine Gasflamme und hat eine Gleichrichtereigenschaft, da in der Flamme 18 Ladungsträger unterschiedlicher Polaritäten vorliegen, deren Mobilität sich stark unterscheidet. Dadurch fließt vorwiegend während einer Halbperiode der Messspannung, während welcher letztere ein bestimmtes Vorzeichen hat, der Ionisationsstrom von oder zu der lonisationselektrode 16. Wenn die Flamme 18 erlischt, kommt auch der Ionisationsstrom zum Erliegen, was durch die Messeinheit 20 messbar ist. Falls dies geschieht, können geeignete Sicherheitsmaßnahmen getroffen werden, beispielsweise kann die Gaszufuhr abgeschaltet werden.The flame 18 is preferably a gas flame and has a rectifying property, since there are 18 carriers of different polarities in the flame, the mobility of which differs greatly. As a result, the ionization current from or to the ionization electrode 16 flows predominantly during a half-period of the measurement voltage, during which the latter has a certain sign. When the flame 18 goes out, the ionization current also comes to a standstill, which can be measured by the measuring unit 20. If this happens, appropriate safety measures can be taken, for example, the gas supply can be switched off.

Die Auswertung der Signale der Messeinheit und die Steuerung der Spannungserzeugungseinheit 12 erfolgt in der Steuereinheit 24 der Flammenüberwachungsvorrichtung. Die Steuereinheit 24 steuert die Spannungserzeugungseinheit 12 mittels eines ersten, vorzugsweise pulsweitenmodulierten Steuersignals 26a, das über eine erste Signalleitung 28a von der Steuereinheit 24 an die Spannungserzeugungseinheit 12 übertragen wird. Über eine zweite Signalleitung 28b überträgt die Steuereinheit 24 ein zweites, vorzugsweise pulsweitenmoduliertes Steuersignal 26b an die Messeinheit 20. Das erste und zweite Steuersignal können jedoch gegebenenfalls eine andere Modulationsart aufweisen. Das zweite Steuersignal 26b dient vorwiegend zur Vorgabe einer Messfrequenz, kann jedoch auch zum Steuern von Betriebsparametern der Messeinheit 20 genutzt werden. Über eine dritte Signalleitung 28c empfängt die Steuereinheit 24 eine erste dynamische Rückmeldung 30a von der Spannungserzeugungseinheit 12 der Spannungserzeugungs- und Messanordnung 10. Über eine vierte Signalleitung 28d empfängt die Steuereinheit 24 eine zweite dynamische Rückmeldung 30b von der Messeinheit 20. Die erste dynamische Rückmeldung 30a und die zweite dynamische Rückmeldung 30b sind jeweils vorzugsweise pulsweitenmodulierte Signale, wobei ein Tastverhältnis der ersten dynamischen Rückmeldung 30a und der zweiten dynamischen Rückmeldung 30b einen kontinuierlichen Wertebereich hat und zeitabhängig ist. Der Wert des Tastverhältnisses kodiert eine tatsächlich erzeugte Spannung in der Spannungserzeugungseinheit 12 bzw. einen von der Messeinheit 20 gemessenen Ionisationsstrom.The evaluation of the signals of the measuring unit and the control of the voltage generating unit 12 takes place in the control unit 24 of the flame monitoring device. The control unit 24 controls the voltage generation unit 12 by means of a first, preferably pulse-width-modulated control signal 26a, which is transmitted via a first signal line 28a from the control unit 24 to the voltage generation unit 12. The control unit 24 transmits a second, preferably pulse-width-modulated control signal 26b to the measuring unit 20 via a second signal line 28b. However, the first and second control signals may optionally have a different modulation type. The second control signal 26b is primarily used to specify a measuring frequency, but can also be used to control operating parameters of the measuring unit 20. Via a third signal line 28c, the control unit 24 receives a first dynamic feedback 30a from the voltage generating unit 12 of the voltage generating and measuring arrangement 10. Via a fourth signal line 28d, the control unit 24 receives a second dynamic feedback 30b from the measuring unit 20. The first dynamic feedback 30a and the second dynamic feedback 30b are each preferably pulse width modulated signals, wherein a duty cycle of the first dynamic feedback 30a and the second dynamic feedback 30b has a continuous range of values and is time-dependent. The value of the duty cycle encodes an actually generated voltage in the voltage generating unit 12 or an ionization current measured by the measuring unit 20.

In einer Startphase bzw. einem ersten Betriebszustand des Brenners 22 wird von der Vorrichtung 12 zum Erzeugen einer Messspannung eine erste Messspannung 12a erzeugt, welche größer als die Sättigungsspannung ist und an der lonisationselektrode 16 einen ersten Gleichstromanteil bzw. ersten Ionisationsstrom 16a hervorruft. Die erste Messspannung 12a und der erste Ionisationsstrom 16a werden sodann durch die Messeinheit 20 erfasst. Falls der erste Ionisationsstrom 16a größer als ein vorbestimmter Schwellwert ist, wird die Flamme 18 durch die Steuereinheit 24 zum Steuern des Flammenüberwachungssystems erkannt. Daraufhin wird nach Ablauf einer einstellbaren Sicherheitszeit, während derer der erste Ionisationsstrom 16a größer als der vorbestimmte Schwellwert sein muss, ein Betriebszustandssignal durch die Steuereinheit 24 an die Vorrichtung 12 zum Erzeugen der Messspannung zum Ändern der erzeugten Messspannung von der ersten Messspannung 12a zu einer zweiten Messspannung 12b vorgesehen und es erfolgt zugleich eine Umschaltung von dem ersten Betriebszustand in einen zweiten Betriebszustand bzw. einen modulierenden Betrieb des Brenners 22 in Reaktion auf das Betriebszustandssignal. Hierbei ist die zweite Messspannung 12b kleiner als die Sättigungsspannung. Weiterhin ist vorgesehen, dass das Betriebszustandssignal der Steuereinheit 24 zum Steuern des Flammenüberwachungssystems mit dem Steuersignal an die Spannungserzeugungseinheit 12 zum Erzeugen der lonisationsspannung übertragen wird, wobei das Steuersignal derart moduliert wird, dass dieses eine Information über den Betriebszustand des Brenners aufweist.In a starting phase or a first operating state of the burner 22, a first measuring voltage 12a is generated by the device 12 for generating a measuring voltage, which is greater than the saturation voltage and at the ionization 16 causes a first DC component or first ionization 16a. The first measurement voltage 12a and the first ionization current 16a are then detected by the measuring unit 20. If the first ionization current 16a is greater than a predetermined threshold, the flame 18 is detected by the control unit 24 for controlling the flame monitoring system. Thereafter, upon expiration of an adjustable safety time during which the first ionization current 16a must be greater than the predetermined threshold, an operating condition signal is sent by the control unit 24 to the measurement voltage generating means 12 for changing the generated measurement voltage from the first measurement voltage 12a to a second measurement voltage 12b provided and there is also a switchover from the first operating state to a second operating state or a modulating operation of the burner 22 in response to the operating state signal. Here, the second measuring voltage 12b is smaller than the saturation voltage. It is further provided that the operating state signal of the control unit 24 for controlling the flame monitoring system is transmitted with the control signal to the voltage generation unit 12 for generating the ionisation voltage, wherein the control signal is modulated so that it has information about the operating state of the burner.

Bei Umschaltung von dem ersten Betriebszustand des Brenners 22 in den zweiten Betriebszustand wird von der Vorrichtung 12 zum Erzeugen einer Messspannung die zweite Messspannung 12b erzeugt, welche an der lonisationselektrode 16 einen zweiten Gleichstromanteil bzw. zweiten lonisationsstrom 16b hervorruft. Die zweite Messspannung 12b und der zweite lonisationsstrom 16b werden durch die Messeinheit 20 erfasst.When switching from the first operating state of the burner 22 to the second operating state, the second measuring voltage 12b is generated by the device 12 for generating a measuring voltage, which causes a second direct current component or second ionization current 16b at the ionization electrode 16. The second measurement voltage 12b and the second ionization current 16b are detected by the measurement unit 20.

Die Steuereinheit 24 ist dazu ausgelegt, den von der Messeinheit 20 erfassten zweiten lonisationsstrom 16b mit wenigstens einem vorgegebenen oberen und/oder unteren Schwellenwert zu vergleichen und ein Fehlersignal zu erzeugen, wenn der Messwert den oberen Schwellwert übertrifft oder den unteren Schwellwert unterschreitet. Die Steuereinheit 24 kann außerdem basierend auf dem Vergleich des lonisationsstroms 16b mit dem oberen Schwellwert und/oder dem unteren Schwellwert eine Korrektur bzw. Nachregelung der Verbrennungsgüte vornehmen. Weiterhin ist die Steuereinheit 24 dazu ausgelegt, den zweiten lonisationsstrom 16b in ein Flammenzustandssignal umzuwandeln, auf Basis dessen eine Bewertung der Flammeneigenschaften und der Flammenqualität erfolgen kann.The control unit 24 is designed to compare the second ionization current 16b detected by the measuring unit 20 with at least one predetermined upper and / or lower threshold value and to generate an error signal if the measured value exceeds the upper threshold value or falls below the lower threshold value. The control unit 24 may also perform a correction of the combustion quality based on the comparison of the ionization current 16b with the upper threshold and / or the lower threshold. Furthermore, the control unit 24 is configured to convert the second ionization current 16b into a flame condition signal, on the basis of which an evaluation of the flame characteristics and the flame quality can take place.

Fig. 3 zeigt ein Ablaufdiagramm des Verfahrens zum Variieren der Messspannung der Vorrichtung zum Erzeugen der Messspannung zur auf Ionisationsstrommessung basierenden Flammenerkennung des Brenners 22 mit den nachfolgenden Schritten. Fig. 3 shows a flowchart of the method for varying the measurement voltage of the device for generating the measurement voltage for ionization current-based flame detection of the burner 22 with the subsequent steps.

In Schritt S10 wird die erste Messspannung 12a zum Erzeugen des ersten lonisationsstroms 16a an der lonisationselektrode 16 des Flammenüberwachungssystems in dem ersten Betriebszustand des Brenners 22 durch die Vorrichtung 12 zum Erzeugen der Messspannung erzeugt, wobei der erste Betriebszustand des Brenners 22 die Startphase des Brenners 22 ist.In step S10, the first measurement voltage 12a for generating the first ionization current 16a is generated at the ionization electrode 16 of the flame monitoring system in the first operating state of the burner 22 by the measuring voltage generating means 12, the first operating state of the burner 22 being the start phase of the burner 22 ,

In Schritt S 20 erfolgt ein Erfassen der ersten, durch die Spannungserzeugungseinheit zum Erzeugen der Messspannung vorgesehene Messspannung 12a und des ersten lonisationsstroms 16a durch die Messeinheit 20.In step S 20, the first measuring voltage 12a provided by the voltage generating unit for generating the measuring voltage and the first ionizing current 16a are detected by the measuring unit 20.

Sofern der lonisationsstrom 16a größer als der vorbestimmte Schwellwert ist, fährt das Verfahren mit Schritt S30 fort. Falls der lonisationsstrom 16a kleiner als der vorbestimmte Schwellwert ist, kehrt das Verfahren zu Schritt S10 zurück.If the ionization current 16a is greater than the predetermined threshold, the process proceeds to step S30. If the ionization current 16a is smaller than the predetermined threshold, the process returns to step S10.

In Schritt S30 wird aufgrund der Tatsache, dass der lonisationsstrom größer als der vorbestimmte Schwellwert ist, die Flamme 18 durch die Steuereinheit 24 zum Steuern des Flammenüberwachungssystems erkannt. Daraufhin wird ein Betriebszustandssignal durch die Steuereinheit 24 an die Vorrichtung 12 zum Erzeugen der Messspannung vorgesehen, das einen Befehlscode zum Ändern der Messspannung von der ersten Messspannung 12a zur zweiten Messspannung 12b enthält. Zugleich erfolgt in Reaktion auf das Betriebszustandssignal der Übergang des Brenners vom ersten Betriebszustand in den zweiten Betriebszustand.In step S30, due to the fact that the ionization current is greater than the predetermined threshold, the flame 18 is detected by the control unit 24 for controlling the flame monitoring system. Thereupon, an operating condition signal is provided by the control unit 24 to the measuring voltage generating means 12, which includes a command code for changing the measuring voltage from the first measuring voltage 12a to the second measuring voltage 12b. At the same time, in response to the operating state signal, the transition of the burner from the first operating state to the second operating state takes place.

In Schritt S40 wird in Reaktion auf das Betriebszustandssignal der Steuereinheit 24 die zweite Messspannung 12b zum Erzeugen des zweiten lonisationsstroms 16b an der lonisationselektrode 16 des Flammenüberwachungssystems in dem zweiten Betriebszustand des Brenners 22 durch die Vorrichtung 12 zum Erzeugen der Messspannung erzeugt.In step S40, in response to the operating state signal of the control unit 24, the second measuring voltage 12b for generating the second ionizing current 16b is generated at the ionization electrode 16 of the flame monitoring system in the second operating state of the burner 22 by the measuring voltage generating means 12.

In Schritt S 50 erfolgt ein Erfassen der zweiten, durch die Spannungserzeugungseinheit 12 zum Erzeugen der Messspannung vorgesehenen Messspannung 12b und des zweiten lonisationsstroms 16b durch die Messeinheit 20.In step S 50, the second measuring voltage 12 b provided by the voltage generating unit 12 for generating the measuring voltage and the second ionizing current 16 b are detected by the measuring unit 20.

Zusätzlich kann die Vorrichtung 12 zum Erzeugen der Messspannung Mittel zur Bestimmung des Betriebszustands des Brenners aufweisen, durch welche der Betriebszustand des Brenners durch Auswerten eines Signals der Steuereinheit 24 bestimmbar ist, und ferner Mittel zum Erkennen einer Änderung des Betriebszustandes des Brenners, beispielsweise vom ersten Betriebszustand in den zweiten Betriebszustand.In addition, the device 12 for generating the measuring voltage may comprise means for determining the operating state of the burner, by means of which the operating state of the burner can be determined by evaluating a signal of the control unit 24, and further means for detecting a change in the operating state of the burner, for example from the first operating state in the second operating state.

Der in diesem Fall alternativ zu Schritt S30 in Fig. 3 mögliche Übergang vom ersten Betriebszustand des Brenners in den zweiten Betriebszustand ist in Fig. 4 gezeigt. Dabei erschließt es sich für den Fachmann, dass einige der im Folgenden beschriebenen Teilschritte mit im Zusammenhang mit Fig. 3 beschriebenen Schritten ohne Weiteres kombinierbar sind.In this case, alternative to step S30 in FIG Fig. 3 possible transition from the first operating state of the burner to the second operating state is in Fig. 4 shown. It will be apparent to those skilled in the art that some of the sub-steps described below are associated with Fig. 3 described steps are readily combinable.

In Schritt S31 erfolgt eine Bestimmung des Betriebszustands des Brenners durch die Mittel zur Bestimmung des Betriebszustands. Diese Bestimmung kann dabei durch Auswerten eines Betriebszustandssignals der Steuereinheit 24 erfolgen.In step S31, a determination is made of the operating state of the burner by the means for determining the operating state. This determination can take place by evaluating an operating state signal of the control unit 24.

Nach der Bestimmung des Betriebszustands des Brenners prüfen in Schritt S32 die in der Vorrichtung 12 zum Erzeugen der Messspannung angelegten Mittel zum Erkennen einer Änderung des Betriebszustandes des Brenners, ob sich der Betriebszustand des Brenners auf ein Steuersignal der Steuereinheit 24 hin vom ersten Betriebszustand zum zweiten Betriebszustand geändert hat.After determining the operating state of the burner, in step S32, the means for detecting a change in the operating state of the burner applied in the measuring voltage generating device 12 checks whether the operating state of the burner is in response to a control signal of the control unit 24 from the first operating state to the second operating state has changed.

Zusätzlich zu oder anstelle einer Sicherheitszeit zwischen dem Start des Brenners und dem Übergang in den zweiten Betriebszustand des Brenners ist auch eine zweite Sicherheitszeit zwischen dem Übergang des Brenners vom ersten Betriebszustand in den zweiten Betriebszustand und dem Ändern der Messspannung von der ersten Messspannung 12a zur zweiten Messspannung 12b vorstellbar. Ist eine solche zweite Sicherheitszeit vorgesehen, erfolgt in Schritt S33 eine Überprüfung, ob die zweite Sicherheitszeit abgelaufen ist, andernfalls wird direkt mit Schritt S34 fortgefahren. Ist die zweite Sicherheitszeit vorgesehen und abgelaufen, wird mit Schritt S34 fortgefahren, andernfalls wird zu Schritt S33 zurückgekehrt. Durch vorsehen der zweiten Sicherheitszeit kann sichergestellt werden, dass sich der Betrieb des Brenners im zweiten Betriebszustand stabilisiert hat bevor eine Änderung der Messspannung von der ersten Messspannung 12a zur zweiten Messspannung 12b erfolgt.In addition to or instead of a safety time between the start of the burner and the transition to the second operating state of the burner, there is also a second safety time between the transition of the burner from the first operating state to the second operating state and the changing of the measuring voltage from the first measuring voltage 12a to the second measuring voltage 12b imaginable. If such a second safety time is provided, a check is made in step S33 as to whether the second safety time has expired, otherwise the procedure continues directly with step S34. If the second safety time is provided and has expired, the process continues to step S34, otherwise it returns to step S33. By providing the second safety time, it can be ensured that the operation of the burner has stabilized in the second operating state before a change of the measuring voltage takes place from the first measuring voltage 12a to the second measuring voltage 12b.

In Schritt S34 wird die von der Vorrichtung 12 zum Erzeugen der Messspannung erzeugte Spannung von der ersten Messspannung 12a zur zweiten Messspannung 12b geändert. Gleichzeitig wird der Messbereich der Messeinheit 20 von einem ersten Messbereich zu einem zweiten Messbereich geändert, und gegebenenfalls werden vorhandene Schwellwerte neu bestimmt.In step S34, the voltage generated by the measuring voltage generating device 12 is changed from the first measuring voltage 12a to the second measuring voltage 12b. At the same time, the measuring range of the measuring unit 20 is changed from a first measuring range to a second measuring range, and possibly existing threshold values are redetermined.

Die Erfindung wurde anhand konkreter Ausgestaltungen näher erläutert, ohne auf die konkreten Ausführungsformen begrenzt zu sein. Insbesondere ist es möglich, Merkmale der unterschiedlichen Ausführungsformen zu kombinieren und auch in den anderen Ausführungsformen einzusetzen.The invention has been explained in more detail with reference to specific embodiments, without being limited to the specific embodiments. In particular, it is possible to combine features of the different embodiments and also to use in the other embodiments.

BezugszeichenlisteLIST OF REFERENCE NUMBERS

1010
Spannungserzeugungs- und MessanordnungVoltage generating and measuring arrangement
1212
Vorrichtung zum Erzeugen einer MessspannungDevice for generating a measuring voltage
12a12a
erste Messspannungfirst measuring voltage
12b12b
zweite Messspannungsecond measuring voltage
1616
lonisationselektrodeionisation
16a16a
erster lonisationsstromfirst ionization current
16b16b
zweiter lonisationsstromsecond ionization current
1818
Flammeflame
2020
Messeinheitmeasuring unit
2222
Brennerburner
2424
Steuereinheitcontrol unit
26a26a
erstes pulsweitenmoduliertes Steuersignalfirst pulse width modulated control signal
26b26b
zweites pulsweitenmoduliertes Steuersignalsecond pulse width modulated control signal
28a28a
erste Signalleitungfirst signal line
28b28b
zweite Signalleitungsecond signal line
28c28c
dritte Signalleitungthird signal line
28d28d
vierte Signalleitungfourth signal line
30a30a
erste dynamische Rückmeldungfirst dynamic feedback
30b30b
zweite dynamische Rückmeldungsecond dynamic feedback

Claims (15)

  1. A method of flame detection based on ionization current measurement with a flame monitoring system in a burner (22) having a first operating state representing a start-up phase of said burner (22) and a second operating state representing a modulation operation of said burner (22), characterized by the steps of:
    generating a first measurement voltage (12a) greater than a saturation voltage for generating a first ionization current (16a) at an ionization electrode (16) of said flame monitoring system in said first operating state of said burner (22) by means of a measuring voltage generating device (12) configured to vary the generated measurement voltage in a voltage range consisting of at least one voltage value above said saturation voltage and at least one voltage value below said saturation voltage, and
    generating a second measurement voltage (12b) less than said saturation voltage for generating a second ionization current (16b) at said ionization electrode (16) of said flame monitoring system in said second operating state of said burner (22) by means of said measuring voltage generating device (12),
    wherein said measuring voltage generating device (12) changes the generated measurement voltage from said first measurement voltage (12a) to said second measurement voltage (12b) when said burner (22) switches from said first operating state to said second operating state.
  2. The method according to claim 1, characterized in that the flame detection system includes a measuring unit (20) electrically connected to said ionization electrode (16) which detects the ionization current generated by said measuring voltage generating device (12).
  3. The method according to claim 2, characterized in that said measuring unit detects said first ionization current (16a) in said first operating state of said burner (22) and said second ionization current (16b) in said second operating state of said burner (22).
  4. The method according to claim 3, characterized in that, in said modulation mode of said burner (22), an air-fuel ratio of said burner (22), in particular an air-gas ratio of said burner (22), is controlled based on second detected ionization current (16b) detected by said measuring unit (20).
  5. The method according to at least one of claims 2 to 4, characterized in that said measuring unit (20) switches from a first measuring range to a second measuring range when said measuring voltage generating device changes the generated measuring voltage from said first measuring voltage (12a) to said second measuring voltage (12b).
  6. The method according to at least one of claims 2 to 5, characterized in that the flame detection comprises a step of comparing at least one threshold value and the ionization current detected by said measuring unit (20).
  7. The method according to claim 6, characterized in that the at least one threshold value is determined again when said measuring voltage generating device (12) changes the generated measurement voltage from said first measurement voltage (12a) to said second measurement voltage (12b).
  8. The method according to at least one of the previous claims, characterized in that said burner (22) switches from said first operating state to said second operating state in response to an operating state signal of a control unit (24) for controlling said flame monitoring system.
  9. The method according to claim 8, characterized in that said operating state signal of said control unit (24) for controlling the flame monitoring system is a pulse width modulated signal.
  10. The method according to claim 8, characterized in that said operating state signal of said control unit (24) for controlling said flame monitoring system is transmitted from said control unit (24) to said measuring voltage generating device (12) and said measuring unit (20).
  11. The method according to claim 8, characterized in that said operating state signal of said control unit (24) for controlling said flame monitoring system is transmitted with a control signal to said measuring voltage generating device (12) for generating an ionisation voltage, and the measuring voltage is modulated in such a way, that it carries information about the operating state of said burner (22).
  12. The method according to any one of the preceding claims, characterized in that a safety period between a start-up of said burner (22) and the switching to said second operating state is adjustable.
  13. A burner (22) including a flame monitoring system comprising an ionization electrode (16) and a measuring voltage generating device for flame detection based on ionization current measurement, said burner (22) having a first operating state representing a start-up phase of said burner (22). and a second operating state representing a modulation operation of said burner (22), characterized by:
    means for generating a first measurement voltage (12a) greater than a saturation voltage so as to generate a first ionization current (16a) at an ionization electrode (16) of the flame monitoring system in said first operating state of said burner (22) and for generating a second measuring voltage (12b) less than said saturation voltage so as to generate a second ionisation current (16b) at said ionisation electrode (16) of said flame monitoring system in said second operating state of said burner (22), wherein
    said measuring voltage generating device is configured to vary the generated measurement voltage in a voltage range consisting of at least one voltage value above said saturation voltage and at least one voltage value below said saturation voltage, and wherein said measuring voltage generating device (12) changes the generated measuring voltage from said first measuring voltage (12a) to said second measuring voltage (12b) when said burner (22) switches from said first operating state to said second operating state.
  14. The burner (22) according to claim 13, characterized in that said burner comprises means for determining an operating state of said burner (22).
  15. The burner (22) according to claim 14, characterized in that the operating state of said burner (22) is determinable by said means for determining the operating state of said burner (22) in response to an operating state signal of a control unit (24) for controlling said flame monitoring system of said burner (22).
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102019119214A1 (en) * 2019-07-16 2021-01-21 Vaillant Gmbh Method and device for recalibrating a measuring system for regulating a fuel gas-air mixture in a heating device
EP3869101A1 (en) 2020-02-19 2021-08-25 Pittway Sarl Flame monitoring device for a gas burner appliance and gas burner appliance

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013221511A1 (en) 2013-10-23 2015-04-23 Robert Bosch Gmbh Device for determining an ionization current of a flame
DE102015222155B4 (en) * 2015-11-11 2019-06-19 Viessmann Werke Gmbh & Co Kg Method for controlling a heating unit and heating unit and computer program product for carrying out the control method
DE102018118288A1 (en) * 2018-07-27 2020-01-30 Ebm-Papst Landshut Gmbh Method for monitoring and regulating a burner flame of a heater burner
DE102018120377A1 (en) 2018-08-21 2020-02-27 Truma Gerätetechnik GmbH & Co. KG Heater and method for controlling a blower gas burner
DE102019107367A1 (en) * 2019-03-22 2020-09-24 Vaillant Gmbh Procedure for checking the presence of a non-return valve in a heating system
DE102019003451A1 (en) * 2019-05-16 2020-11-19 Truma Gerätetechnik GmbH & Co. KG Method for monitoring a burner and / or a burning behavior of a burner and burner arrangement
DE102021207690A1 (en) 2021-07-19 2023-01-19 Viessmann Climate Solutions Se METHOD OF CONTROLLING A BURNER OF A HEAT GENERATOR, BURNER, HEAT GENERATOR AND HEATING SYSTEM
WO2023217328A1 (en) * 2022-05-11 2023-11-16 Viessmann Climate Solutions Se Method for operating a burner device
DE102022111802A1 (en) * 2022-05-11 2023-11-16 Viessmann Climate Solutions Se Method for operating a burner device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3215499A (en) * 1960-11-18 1965-11-02 Ici Australia Ltd Apparatus for detecting the presence of organic gases and vapours

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10149383C2 (en) * 2001-10-06 2003-11-20 Bosch Gmbh Robert Gas burner with flame monitoring
DE102004061300B3 (en) * 2004-12-20 2006-07-13 Siemens Ag Method and device for influencing combustion processes
DE102007018122B4 (en) * 2007-04-16 2013-10-17 Viessmann Werke Gmbh & Co Kg Flame monitoring device with a voltage generating and measuring arrangement and method for monitoring a burner by means of the flame monitoring device

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3215499A (en) * 1960-11-18 1965-11-02 Ici Australia Ltd Apparatus for detecting the presence of organic gases and vapours

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102019119214A1 (en) * 2019-07-16 2021-01-21 Vaillant Gmbh Method and device for recalibrating a measuring system for regulating a fuel gas-air mixture in a heating device
EP3869101A1 (en) 2020-02-19 2021-08-25 Pittway Sarl Flame monitoring device for a gas burner appliance and gas burner appliance
WO2021165032A1 (en) 2020-02-19 2021-08-26 Pittway Sarl Flame monitoring device for a gas burner appliance and gas burner appliance

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EP2357410A2 (en) 2011-08-17
DE102010001307A1 (en) 2011-08-18
EP2357410A3 (en) 2018-03-14
DE102010001307B4 (en) 2013-12-24
PL2357410T3 (en) 2020-01-31

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