EP0617234A1 - Flame monitor with flame rod - Google Patents
Flame monitor with flame rod Download PDFInfo
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- EP0617234A1 EP0617234A1 EP94102367A EP94102367A EP0617234A1 EP 0617234 A1 EP0617234 A1 EP 0617234A1 EP 94102367 A EP94102367 A EP 94102367A EP 94102367 A EP94102367 A EP 94102367A EP 0617234 A1 EP0617234 A1 EP 0617234A1
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- Prior art keywords
- circuit
- test
- flame
- ionization
- capacitance
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- 238000012360 testing method Methods 0.000 claims abstract description 46
- 238000012544 monitoring process Methods 0.000 claims description 21
- 238000011156 evaluation Methods 0.000 claims description 17
- 230000008878 coupling Effects 0.000 claims description 8
- 238000010168 coupling process Methods 0.000 claims description 8
- 238000005859 coupling reaction Methods 0.000 claims description 8
- 230000000737 periodic effect Effects 0.000 claims description 2
- 239000003990 capacitor Substances 0.000 abstract description 13
- 238000002485 combustion reaction Methods 0.000 abstract 1
- 238000011161 development Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000004020 conductor Substances 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000003213 activating effect Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
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Classifications
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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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2223/00—Signal processing; Details thereof
- F23N2223/08—Microprocessor; Microcomputer
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N2227/00—Ignition or checking
- F23N2227/12—Burner simulation or checking
- F23N2227/16—Checking components, e.g. electronic
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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
- F23N5/24—Preventing development of abnormal or undesired conditions, i.e. safety arrangements
Definitions
- the invention relates to an ionization flame monitor, in particular for automatic burner controls.
- Such an ionization flame monitor should not only be able to reliably detect the presence or absence of a flame in an automatic burner control unit, but should also offer the possibility of using a z. B. from a higher-level automatic control test signal to be checked for its functionality and also allow a statement about the flowing ionization current.
- An essential feature of the invention is that a capacitance is provided which is connected to the secondary circuit of an ignition transformer and is charged to a certain voltage value when no ionization current flows and is discharged when an ionization current flows so that its rate of discharge is a measure of the level of the ionization current
- An input of a monitoring circuit is connected to the capacitance in order to produce an output signal, which indicates the presence of a flame, when the voltage across the capacitance falls below a predetermined voltage value.
- the capacitance is preferably connected to the secondary circuit of the ignition transformer by means of a coupling circuit which, in the simplest case, contains at least one resistance element.
- the coupling circuit can be activated or deactivated by an externally supplied signal.
- the monitoring circuit is preferably designed as a threshold switch with hysteresis.
- a test circuit is provided which is connected to the discharge circuit of the capacitance in order to simulate the absence of the flame during operation when the monitoring circuit has an output signal. This makes it when testing the ionization flame monitor under no circumstances possible to simulate a flame.
- the test circuit preferably has a transistor circuit to which a test signal is applied in order to apply a voltage to the input of the monitoring circuit as a function of the test signal, which voltage simulates the absence of the flame.
- an optocoupler is provided in the transistor circuit in order to galvanically isolate the test signal from the other ionization flame monitor circuit.
- the speed of the discharge indicates the size of the ionization current via the time constant of the capacitance.
- an evaluation circuit which is supplied with the output signal of the monitoring circuit is preferably provided and measures the time period immediately after the termination of the test signal until the voltage across the capacitance has fallen below the predetermined voltage value.
- the evaluation circuit has a microprocessor which can also generate the test signal at the same time.
- the evaluation circuit can generate the test signal in predetermined periodic periods or alternatively depending on the operating conditions of the automatic burner control unit.
- the proposed circuit can easily be miniaturized in such a way that it can be accommodated in a plug of a cable which forms an electrical connection of the ignition electrode.
- a coupling circuit K a capacitance C3.
- the capacitor C3 is charged to the operating voltage U B via the resistor R3.
- an ionization current I F flows due to the flame development, the capacitor C3 is discharged.
- an input S e of a monitoring circuit S connected, which detects when the capacitor C3 is discharged, that is, when the voltage U C3 across the capacitor C3 has dropped below a predetermined voltage value.
- the output of the monitoring circuit S then emits a corresponding output signal S a , which can be evaluated by an evaluation circuit A.
- a test circuit T is connected to the circuit point E via a dashed line, which pulls the input S e of the monitoring circuit S to the operating voltage U B in response to a test signal “Test”.
- the ionization flame monitor is only tested during operation, ie if there is a flame. Because of this and the described discharge of the capacitance C3 by the ionization current, it cannot happen that a flame is simulated during the test process, which is very important from a safety point of view.
- a preferred overall circuit of the ionization flame monitor, alternative circuit variants of the test circuit T and an interface circuit between the output S a of the monitoring circuit S and an evaluation circuit A and their function are described in more detail below with reference to FIGS. 2 to 6.
- the circuit shown in FIG. 2 has a voltage generator circuit which generates the operating voltage U B.
- a surge arrester F 1 is coupled in FIG. 2 to the line carrying the ionization current I F , which is led at its other end to a protective conductor terminal P E.
- the coupling circuit K has a resistance element R2, which also functions as a safety resistor in the event of a short circuit in the ionization input.
- the monitoring circuit consists of the series circuit of R3 with C3 and a threshold switch V5 connected to the circuit point E with hysteresis. If the voltage at switching point E rises above 2/3 U B , the output signal of the integrated threshold switch V5 switches to the "0" state. As long as there is no flame, the capacitor C3 is therefore charged to the operating voltage U B , and the output of the threshold switch V5 is "0".
- the function-time diagram in FIG. 6 shows the time behavior of the ionization current, the capacitor voltage U C3 in the presence and absence of the ionization current I F and in the case of the test signal with the flame present, and the time behavior of the output signal S a at the output of the monitoring circuit S.
- the test circuit T pulls the input signal S e of the monitoring circuit S when the test signal "Test" is applied to the operating voltage U B.
- the output signal S a of the monitoring circuit S ie the threshold switch V5
- the evaluation circuit A which can be coupled to the output S a of the monitoring circuit S, makes it possible to measure the length of time dt that the capacitor C3 needs to discharge to 1/3 U B when the flame is present.
- This time period dt or discharge rate is a measure of the strength of the flowing ionization current.
- the ionization current is inversely proportional to the time period dt.
- the time period dt is also dependent on the capacitance of the capacitor C3, the resistance R2 and the flame resistance.
- the first variant T 1 shown in FIG. 3 of the test circuit contains a transistor circuit consisting of two transistors V7 and V8, which applies the operating voltage U B to the circuit point E when the "Test" signal is applied.
- the second variant T2 of the test circuit contains an optocoupler V9 according to FIG. 4, which causes a galvanic isolation of the test signal "Test” from the rest of the circuit of the ionization flame monitor.
- FIG. 5 shows an optocoupler V10, which enables a galvanic decoupling of the evaluation circuit A from the output of the monitoring circuit S.
- the evaluation circuit A itself is not shown, but it has become clear that this circuit should preferably have an evaluation circuit for the period dt.
- the evaluation circuit A particularly preferably has a microprocessor which can also generate the test signal "Test".
- the 1 shows the possibility of activating or deactivating the coupling circuit K by means of a coupling activation signal K E.
- the signal K E can also be generated by the microprocessor of the evaluation circuit.
Abstract
Description
Die Erfindung betrifft einen Ionisationsflammenwächter insbesondere für Gasfeuerungsautomaten. Ein solcher Ionisationsflammenwächter soll nicht nur sicher das Vorhandensein oder Nichtvorhandensein einer Flamme in einem Gasfeuerungsautomaten erkennen können, sondern auch die Möglichkeit bieten, auf ein z. B. von einer übergeordneten automatischen Steuerung erzeugtes Prüfsignal hin auf seine Funktionstüchtigkeit geprüft zu werden und außerdem eine Aussage über den fließenden Ionisationsstrom ermöglichen.The invention relates to an ionization flame monitor, in particular for automatic burner controls. Such an ionization flame monitor should not only be able to reliably detect the presence or absence of a flame in an automatic burner control unit, but should also offer the possibility of using a z. B. from a higher-level automatic control test signal to be checked for its functionality and also allow a statement about the flowing ionization current.
Es ist deshalb Aufgabe der Erfindung, einen einfachen und sicheren Ionisationsflammenwächter so zu ermöglichen, daß seine Funktion während des Betriebs prüfbar und daß er gleichzeitig ein Signal erzeugt, das eine Aussage über die Größe des fließenden Ionisationsstroms zuläßt.It is therefore an object of the invention to enable a simple and safe ionization flame monitor so that its function can be checked during operation and that at the same time it generates a signal which allows a statement about the size of the flowing ionization current.
Eine Lösung dieser Aufgabe ist erfindungsgemäß durch die in den Ansprüchen gekennzeichneten Merkmale angegeben. Wesentliches Merkmal der Erfindung ist, daß eine mit dem Sekundärkreis eines Zündübertragers verbundene Kapazität vorgesehen ist, die, wenn kein Ionisationsstrom fließt, auf einen bestimmten Spannungswert aufgeladen ist und bei Fließen eines Ionisationsstroms so entladen wird, daß deren Entladegeschwindigkeit ein Maß für die Höhe des Ionisationsstroms ergibt, wobei ein Eingang einer Überwachungsschaltung mit der Kapazität verbunden ist, um, wenn die Spannung über der Kapazität einen vorbestimmten Spannungswert unterschreitet, ein Ausgangssignal zu erzeugen, welches das Vorhandensein einer Flamme angibt.According to the invention, a solution to this problem is given by the features characterized in the claims. An essential feature of the invention is that a capacitance is provided which is connected to the secondary circuit of an ignition transformer and is charged to a certain voltage value when no ionization current flows and is discharged when an ionization current flows so that its rate of discharge is a measure of the level of the ionization current An input of a monitoring circuit is connected to the capacitance in order to produce an output signal, which indicates the presence of a flame, when the voltage across the capacitance falls below a predetermined voltage value.
Die Verbindung der Kapazität mit dem Sekundärkreis des Zündübertragers erfolgt bevorzugt durch eine Koppelschaltung, die im einfachsten Fall wenigstens ein Widerstandsglied enthält. Um den Flammenwächter in Aktion zu setzen, kann bei einer Alternative die Koppelschaltung durch ein von außen zugeführtes Signal aktiviert oder desaktiviert werden.The capacitance is preferably connected to the secondary circuit of the ignition transformer by means of a coupling circuit which, in the simplest case, contains at least one resistance element. In order to set the flame monitor in action, the coupling circuit can be activated or deactivated by an externally supplied signal.
Die Überwachungsschaltung ist bevorzugt als Schwellwertschalter mit Hysterese ausgeführt. Zur Prüfung des Ionisationsflammenwächters ist eine Testschaltung vorgesehen, die mit dem Entladekreis der Kapazität verbunden ist, um während des Betriebs bei vorhandenem Ausgangssignal der Überwachungsschaltung ein Nichtvorhandensein der Flamme zu simulieren. Dadurch ist es bei der Prüfung des Ionisationsflammenwächters in keinem Fall möglich, eine Flamme zu simulieren.The monitoring circuit is preferably designed as a threshold switch with hysteresis. To test the ionization flame monitor, a test circuit is provided which is connected to the discharge circuit of the capacitance in order to simulate the absence of the flame during operation when the monitoring circuit has an output signal. This makes it when testing the ionization flame monitor under no circumstances possible to simulate a flame.
Bevorzugt weist die Testschaltung eine mit einem Prüfsignal beaufschlagte Transistorschaltung auf, um abhängig vom Prüfsignal dem Eingang der Überwachungsschaltung eine Spannung anzulegen, welche das Nichtvorhandensein der Flamme simuliert. In einer bevorzugten Weiterbildung ist in der Transistorschaltung ein Optokoppler vorgesehen, um das Prüfsignal galvanisch von der sonstigen Ionisationsflammenwächterschaltung zu isolieren.The test circuit preferably has a transistor circuit to which a test signal is applied in order to apply a voltage to the input of the monitoring circuit as a function of the test signal, which voltage simulates the absence of the flame. In a preferred development, an optocoupler is provided in the transistor circuit in order to galvanically isolate the test signal from the other ionization flame monitor circuit.
Die Geschwindigkeit der Entladung läßt über die Zeitkonstante der Kapazität auf die Größe des Ionisationsstroms schließen. Aus diesem Grund ist bevorzugt eine mit dem Ausgangssignal der Überwachungsschaltung beaufschlagte Auswerteschaltung vorgesehen, die unmittelbar auf die Beendigung des Prüfsignals die Zeitdauer mißt, bis die Spannung an der Kapazität den vorbestimmten Spannungswert unterschritten hat.The speed of the discharge indicates the size of the ionization current via the time constant of the capacitance. For this reason, an evaluation circuit which is supplied with the output signal of the monitoring circuit is preferably provided and measures the time period immediately after the termination of the test signal until the voltage across the capacitance has fallen below the predetermined voltage value.
In einer Weiterbildung der Erfindung weist die Auswerteschaltung einen Mikroprozessor auf, der auch gleichzeitig das Prüfsignal erzeugen kann. Die Auswerteschaltung kann das Prüfsignal in vorgegebenen periodischen Zeitabschnitten erzeugen oder alternativ abhängig von Betriebsbedingungen des Gasfeuerungsautomaten.In a development of the invention, the evaluation circuit has a microprocessor which can also generate the test signal at the same time. The evaluation circuit can generate the test signal in predetermined periodic periods or alternatively depending on the operating conditions of the automatic burner control unit.
Die vorgeschlagene Schaltung läßt sich leicht so miniaturisieren, daß sie in einem Stecker eines Kabels unterbringbar ist, welcher einen elektrischen Anschluß der Zündelektrode bildet.The proposed circuit can easily be miniaturized in such a way that it can be accommodated in a plug of a cable which forms an electrical connection of the ignition electrode.
Nachfolgend wird die Erfindung in mehreren Ausführungsformen anhand der Zeichnung näher erläutert. Von den Zeichungsfiguren zeigen:
- Fig. 1
- Ein prinzipielles Blockschaltbild des erfindungsgemäßen Ionisationsflammenwächters;
- Fig. 2
- eine bevorzugte Ausführungsart des Ionisationsflammenwächters zusammen mit einer Betriebsspannungs-Generatorschaltung;
- Fig. 3
- ein erstes Ausführungsbeispiel der Testschaltung;
- Fig. 4
- eine zweite Ausführungsart der Testschaltung;
- Fig. 5
- eine Ausführungsart einer Schnittstellenschaltung zwischen dem Ausgang der Überwachungsschaltung und dem Eingang der Auswerteschaltung; und
- Fig. 6
- ein Funktions-Zeitdiagramm des erfindungsgemäßen Ionisationsflammenwächters gemäß Fig. 2.
- Fig. 1
- A basic block diagram of the ionization flame monitor according to the invention;
- Fig. 2
- a preferred embodiment of the ionization flame monitor together with an operating voltage generator circuit;
- Fig. 3
- a first embodiment of the test circuit;
- Fig. 4
- a second embodiment of the test circuit;
- Fig. 5
- an embodiment of an interface circuit between the output of the monitoring circuit and the input of the evaluation circuit; and
- Fig. 6
- 2 shows a functional timing diagram of the ionization flame monitor according to the invention according to FIG. 2.
Gemäß dem in Fig. 1 dargestellten Prinzip-Blockschaltbild des Ionisationsflammenwächters ist mit der Sekundärseite b eines Zündübertragers Ü, an der ein Zündfunke erzeugt wird, über eine Koppelschaltung K eine Kapazität C₃ verbunden. Solange zwischen der Zündelektrode Z und der schematisch angedeuten Masseleitung keine Flamme vorhanden ist, wird der Kondensator C₃ über den Widerstand R₃ auf die Betriebsspannung UB aufgeladen. Sobald infolge der Flammenentwicklung ein Ionisationsstrom IF fließt, wird der Kondensator C₃ entladen. An das mit E bezeichnete Ende des Kondensators C₃ ist ein Eingang Se einer Überwachungsschaltung S angeschlossen, die erkennt, wenn der Kondensator C₃ entladen ist, d. h., wenn die Spannung UC3 über dem Kondensator C₃ unter einen vorgegebenen Spannungswert abgefallen ist. Der Ausgang der Überwachungschaltung S gibt dann ein entsprechendes Ausgangssignal Sa ab, das von einer Auswerteschaltung A ausgewertet werden kann. Mit dem Schaltungspunkt E ist über eine gestrichelt gezeichnete Leitung eine Testschaltung T verbunden, welche auf ein Prüfsignal "Test" hin den Eingang Se der Überwachungsschaltung S auf die Betriebsspannung UB zieht. Der Test des Ionisationsflammenwächters wird nur im Betrieb, d.h. bei vorhandener Flamme, durchgeführt. Dadurch und durch die geschilderte Entladung der Kapazität C₃ durch den Ionisationsstrom kann es nicht vorkommen, daß beim Testvorgang eine Flamme simuliert wird, was aus sicherheitstechnischen Gesichtspunkten sehr wichtig ist.According to the principle block diagram of the ionization flame monitor shown in Fig. 1 is connected to the secondary side b of an ignition transformer U, on which an ignition spark is generated, via a coupling circuit K, a capacitance C₃. As long as there is no flame between the ignition electrode Z and the schematically indicated ground line, the capacitor C₃ is charged to the operating voltage U B via the resistor R₃. As soon as an ionization current I F flows due to the flame development, the capacitor C₃ is discharged. At the end of the capacitor labeled E is C₃ an input S e of a monitoring circuit S connected, which detects when the capacitor C₃ is discharged, that is, when the voltage U C3 across the capacitor C₃ has dropped below a predetermined voltage value. The output of the monitoring circuit S then emits a corresponding output signal S a , which can be evaluated by an evaluation circuit A. A test circuit T is connected to the circuit point E via a dashed line, which pulls the input S e of the monitoring circuit S to the operating voltage U B in response to a test signal “Test”. The ionization flame monitor is only tested during operation, ie if there is a flame. Because of this and the described discharge of the capacitance C₃ by the ionization current, it cannot happen that a flame is simulated during the test process, which is very important from a safety point of view.
Nachfolgend werden anhand der Fig. 2 bis 6 eine bevorzugte Gesamtschaltung des Ionisationsflammenwächters, alternative Schaltungsvarianten der Testschaltung T und eine Schnittstellenschaltung zwischem dem Ausgang Sa der Überwachungsschaltung S und einer Auswerteschaltung A sowie deren Funktion näher beschrieben.A preferred overall circuit of the ionization flame monitor, alternative circuit variants of the test circuit T and an interface circuit between the output S a of the monitoring circuit S and an evaluation circuit A and their function are described in more detail below with reference to FIGS. 2 to 6.
Die in Fig. 2 gezeigte Schaltung weist außer der eigentlichen Ionisationsflammenwächter-Schaltung eine die Betriebsspannung UB erzeugende Spannungsgeneratorschaltung auf. Ein üblicher aus einem Widerstand R₁, einem Kondensator C₁, einer Zweiweg-Gleichrichterschaltung V₁ und einer Zenerdiode V₂ bestehender Spannungsgenerator, wobei die Gleichrichterschaltung zwischen einer Phase L₁ und einem Nulleiter N angeschlossen ist, erzeugt die zur Aufladung des Kondensators C₃ über den Widerstand R₃ dienende Betriebsspannung UB. Ferner ist in Fig. 2 noch ein Überspannungsableiter F₁ mit der den Ionisationsstrom IF führenden Leitung gekoppelt, welcher an seinem anderen Ende zu einer Schutzleiterklemme PE geführt ist. Die Koppelschaltung K weist, wie bereits erwähnt, ein Widerstandsglied R₂ auf, welches auch als Sicherungswiderstand bei Kurzschluß des Ionisationseingangs fungiert. Die Überwachungsschaltung besteht aus der Serienschaltung von R₃ mit C₃ und einem mit dem Schaltungspunkt E verbundenen Schwellwertschalter V₅ mit Hysterese. Steigt die Spannung am Schaltungspunkt E über 2/3 UB, schaltet das Ausgangssignal des integrierten Schwellwertschalter V₅ in den Zustand "0". Solange keine Flamme vorhanden ist, ist der Kondensator C₃ demnach auf die Betriebsspannung UB aufgeladen, und der Ausgang des Schwellwertschalter V₅ ist "0". Fließt jedoch aufgrund einer Flammenentwicklung ein Ionisationsstrom, wird der Kondensator C₃ über die Koppelschaltung K entladen und die Spannung am Eingang von V₅ sinkt unter den vorgegebenen Spannungswert, d.h., im Ausführungsbeispiel unter 1/3 UB. Dann geht das Ausgangssignal Sa des Schwellwertschalters V₅ auf "1". Das Funktions-Zeitdiagramm in Fig. 6 zeigt das Zeitverhalten des Ionisationsstroms, der Kondensatorspannung UC3 bei vorhandenem und nichtvorhandenem Ionisationsstrom IF und im Fall des Testsignals bei vorhandener Flamme sowie das Zeitverhalten des Ausgangssignal Sa am Ausgang der Überwachungsschaltung S. Die Testschaltung T zieht das Eingangssignal Se der Überwachungsschaltung S bei Anliegen des Testsignals "Test" auf die Betriebsspannung UB. Das Ausgangssignal Sa der Überwachungsschaltung S, d.h. des Schwellwertschalters V₅, gibt in diesem Moment an: "keine Flamme". Der Test wird also während des Betriebs, bei vorhandener Flamme, durchgeführt. Dies ist aus sicherheitstechnischen Gesichtspunkten wichtig, und es ist bei der Durchführung des Tests in keinem Falle möglich, eine Flamme zu simulieren. Die Auswerteschaltung A, die mit dem Ausgang Sa der Überwachungsschaltung S zusammengekoppelt werden kann, ermöglichst es, die Zeitdauer dt zu messen, die der Kondensator C₃ benötigt, sich bei vorhandener Flamme auf 1/3 UB zu entladen. Diese Zeitdauer dt oder Entladegeschwindigkeit ist ein Maß für die Stärke des fließenden Ionisationsstroms. Der Ionisationsstrom ist umgekehrt proportional zur Zeitdauer dt. Selbstverständlich ist die Zeitdauer dt auch von der Kapazität des Kondensators C₃, dem Widerstand R₂ und dem Flammenwiderstand abhängig.In addition to the actual ionization flame monitor circuit, the circuit shown in FIG. 2 has a voltage generator circuit which generates the operating voltage U B. A usual from a resistor R₁, a capacitor C₁, a two-way rectifier circuit V₁ and a Zener diode V₂ existing voltage generator, the rectifier circuit being connected between a phase L₁ and a neutral conductor N, generates the charge for the capacitor C₃ via the resistor R₃ serving operating voltage U B. Furthermore, a surge arrester F 1 is coupled in FIG. 2 to the line carrying the ionization current I F , which is led at its other end to a protective conductor terminal P E. The coupling circuit K, as already mentioned, has a resistance element R₂, which also functions as a safety resistor in the event of a short circuit in the ionization input. The monitoring circuit consists of the series circuit of R₃ with C₃ and a threshold switch V₅ connected to the circuit point E with hysteresis. If the voltage at switching point E rises above 2/3 U B , the output signal of the integrated threshold switch V₅ switches to the "0" state. As long as there is no flame, the capacitor C₃ is therefore charged to the operating voltage U B , and the output of the threshold switch V₅ is "0". However, due to a flame development, an ionization current flows, the capacitor C₃ is discharged via the coupling circuit K and the voltage at the input of V₅ drops below the predetermined voltage value, that is, in the exemplary embodiment below 1/3 U B. Then the output signal S a of the threshold switch V₅ goes to "1". The function-time diagram in FIG. 6 shows the time behavior of the ionization current, the capacitor voltage U C3 in the presence and absence of the ionization current I F and in the case of the test signal with the flame present, and the time behavior of the output signal S a at the output of the monitoring circuit S. The test circuit T pulls the input signal S e of the monitoring circuit S when the test signal "Test" is applied to the operating voltage U B. The output signal S a of the monitoring circuit S, ie the threshold switch V₅, indicates at this moment: "no flame". The test is therefore carried out during operation with the flame present. This is for security reasons Important aspects, and it is in no way possible to simulate a flame when carrying out the test. The evaluation circuit A, which can be coupled to the output S a of the monitoring circuit S, makes it possible to measure the length of time dt that the capacitor C₃ needs to discharge to 1/3 U B when the flame is present. This time period dt or discharge rate is a measure of the strength of the flowing ionization current. The ionization current is inversely proportional to the time period dt. Of course, the time period dt is also dependent on the capacitance of the capacitor C₃, the resistance R₂ and the flame resistance.
Die in Fig. 3 gezeigte erste Variante T₁ der Testschaltung enthält eine aus zwei Transistoren V₇ und V₈ bestehende Transistorschaltung, die beim Anlegen des Signals "Test" die Betriebsspannung UB an den Schaltungspunkt E legt. Die zweite Variante T₂ der Testschaltung enthält gemäß Fig. 4 einen Optokoppler V₉, der eine galvanische Trennung des Testsignals "Test" von der übrigen Schaltung des Ionisationsflammenwächters bewirkt.The first variant T 1 shown in FIG. 3 of the test circuit contains a transistor circuit consisting of two transistors V₇ and V₈, which applies the operating voltage U B to the circuit point E when the "Test" signal is applied. The second variant T₂ of the test circuit contains an optocoupler V₉ according to FIG. 4, which causes a galvanic isolation of the test signal "Test" from the rest of the circuit of the ionization flame monitor.
Die Schaltung gemäß Fig. 5 zeigt einen Optokoppler V₁₀, der eine galvanische Entkopplung der Auswerteschaltung A vom Ausgang der Überwachungsschaltung S ermöglicht.5 shows an optocoupler V₁₀, which enables a galvanic decoupling of the evaluation circuit A from the output of the monitoring circuit S.
Die Auswerteschaltung A selbst ist nicht dargestellt, es ist jedoch deutlich geworden, daß diese Schaltung bevorzugt eine Auswerteschaltung für die Zeitdauer dt aufweisen sollte. Insbesondere bevorzugt weist die Auswerteschaltung A einen Mikroprozessor auf, der auch das Testsignal "Test" erzeugen kann.The evaluation circuit A itself is not shown, but it has become clear that this circuit should preferably have an evaluation circuit for the period dt. The evaluation circuit A particularly preferably has a microprocessor which can also generate the test signal "Test".
In Fig. 1 ist noch die Möglichkeit dargestellt, die Koppelschaltung K mittels eines Koppeleinschaltsignals KE zu aktivieren bzw. zu desaktivieren. Das Signal KE kann ebenfalls von dem Mikroprozessor der Auswerteschaltung erzeugt werden.1 shows the possibility of activating or deactivating the coupling circuit K by means of a coupling activation signal K E. The signal K E can also be generated by the microprocessor of the evaluation circuit.
Claims (10)
gekennzeichnet durch eine mit dem Sekundärkreis (b) eines Zündübertragers (Ü) verbundene Kapazität (C₃), die bei nicht vorhandener Flamme auf einen bestimmten Spannungswert (UB) aufgeladen ist und von einem bei Vorhandensein einer Flamme fließenden
Ionisationsstrom (IF) so entladen wird, daß deren Entladegeschwindigkeit ein Maß für die Höhe des Ionisationsstroms ergibt,
wobei ein Eingang (Se) einer Überwachungsschaltung (S) mit der Kapazität (C₃) verbunden ist um, wenn die Spannung (UC3) über der Kapazität (C₃) einen vorbestimmten Spannungswert unterschreitet, ein Ausgangssignal (Sa) zu erzeugen, welches das Vorhandensein einer Flamme angibt.Ionization flame monitor especially for automatic burner controls,
characterized by a connected to the secondary circuit (b) of an ignition transformer (Ü) capacitance (C₃) which is charged to a certain voltage value (U B ) in the absence of a flame and which flows in the presence of a flame
Ionization current (I F ) is discharged in such a way that its rate of discharge gives a measure of the level of the ionization current,
wherein an input (S e ) of a monitoring circuit (S) is connected to the capacitance (C₃) in order to generate an output signal (S a ) which, when the voltage (U C3 ) across the capacitance (C₃) falls below a predetermined voltage value indicates the presence of a flame.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4309454A DE4309454C2 (en) | 1993-03-24 | 1993-03-24 | Ionization flame monitor |
| DE4309454 | 1993-03-24 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0617234A1 true EP0617234A1 (en) | 1994-09-28 |
Family
ID=6483648
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP94102367A Withdrawn EP0617234A1 (en) | 1993-03-24 | 1994-02-17 | Flame monitor with flame rod |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0617234A1 (en) |
| DE (1) | DE4309454C2 (en) |
Cited By (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0908679A1 (en) * | 1997-10-10 | 1999-04-14 | Electrowatt Technology Innovation AG | Circuit for flame monitoring |
| EP1719947A1 (en) | 2005-05-06 | 2006-11-08 | Siemens Building Technologies HVAC Products GmbH | Method and device for flame monitoring |
| DE102009057121A1 (en) | 2009-12-08 | 2011-06-09 | Scheer Heizsysteme & Produktionstechnik Gmbh | Method for qualitative monitoring of combustion status of boiler system in e.g. industrial combustion, involves determining exhaust gas value of combustion of fuel-air-mixture by boiler-isothermal current and/or voltage characteristic curve |
| EP1983264A3 (en) * | 2007-04-16 | 2014-02-19 | Viessmann Werke GmbH & Co. KG | Flame monitoring device with voltage generator and voltage measuring device |
| US8839815B2 (en) | 2011-12-15 | 2014-09-23 | Honeywell International Inc. | Gas valve with electronic cycle counter |
| US8899264B2 (en) | 2011-12-15 | 2014-12-02 | Honeywell International Inc. | Gas valve with electronic proof of closure system |
| US8905063B2 (en) | 2011-12-15 | 2014-12-09 | Honeywell International Inc. | Gas valve with fuel rate monitor |
| US8947242B2 (en) | 2011-12-15 | 2015-02-03 | Honeywell International Inc. | Gas valve with valve leakage test |
| US9074770B2 (en) | 2011-12-15 | 2015-07-07 | Honeywell International Inc. | Gas valve with electronic valve proving system |
| US9234661B2 (en) | 2012-09-15 | 2016-01-12 | Honeywell International Inc. | Burner control system |
| US9557059B2 (en) | 2011-12-15 | 2017-01-31 | Honeywell International Inc | Gas valve with communication link |
| US9645584B2 (en) | 2014-09-17 | 2017-05-09 | Honeywell International Inc. | Gas valve with electronic health monitoring |
| US9683674B2 (en) | 2013-10-29 | 2017-06-20 | Honeywell Technologies Sarl | Regulating device |
| US9835265B2 (en) | 2011-12-15 | 2017-12-05 | Honeywell International Inc. | Valve with actuator diagnostics |
| US9841122B2 (en) | 2014-09-09 | 2017-12-12 | Honeywell International Inc. | Gas valve with electronic valve proving system |
| US9846440B2 (en) | 2011-12-15 | 2017-12-19 | Honeywell International Inc. | Valve controller configured to estimate fuel comsumption |
| US9851103B2 (en) | 2011-12-15 | 2017-12-26 | Honeywell International Inc. | Gas valve with overpressure diagnostics |
| US9995486B2 (en) | 2011-12-15 | 2018-06-12 | Honeywell International Inc. | Gas valve with high/low gas pressure detection |
| US10024439B2 (en) | 2013-12-16 | 2018-07-17 | Honeywell International Inc. | Valve over-travel mechanism |
| US10422531B2 (en) | 2012-09-15 | 2019-09-24 | Honeywell International Inc. | System and approach for controlling a combustion chamber |
| US10503181B2 (en) | 2016-01-13 | 2019-12-10 | Honeywell International Inc. | Pressure regulator |
| US10564062B2 (en) | 2016-10-19 | 2020-02-18 | Honeywell International Inc. | Human-machine interface for gas valve |
| US10697815B2 (en) | 2018-06-09 | 2020-06-30 | Honeywell International Inc. | System and methods for mitigating condensation in a sensor module |
| US11073281B2 (en) | 2017-12-29 | 2021-07-27 | Honeywell International Inc. | Closed-loop programming and control of a combustion appliance |
| WO2023012019A1 (en) * | 2021-08-05 | 2023-02-09 | Truma Gerätetechnik GmbH & Co. KG | Burner having a controller and an ignition and ionisation electrode and method for monitoring and igniting the flame of a burner |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19631821C2 (en) * | 1996-08-07 | 1999-08-12 | Stiebel Eltron Gmbh & Co Kg | Method and device for safety flame monitoring in a gas burner |
| DE59703939D1 (en) * | 1996-05-09 | 2001-08-09 | Stiebel Eltron Gmbh & Co Kg | Process for operating a gas burner |
| DE10027846A1 (en) * | 2000-05-25 | 2001-11-29 | Siemens Building Tech Ag | Signal generator |
| DE10247168B4 (en) * | 2002-10-10 | 2004-09-09 | Karl Dungs Gmbh & Co. Kg | Flame detector with self-test function and process for operational monitoring |
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| US4168949A (en) * | 1977-09-26 | 1979-09-25 | Honeywell Inc. | Flame signal stabilization circuit |
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| US3877864A (en) * | 1974-07-29 | 1975-04-15 | Itt | Spark igniter system for gas appliance pilot ignition |
| US4000961A (en) * | 1975-08-26 | 1977-01-04 | Eclipse, Inc. | Primary flame safeguard system |
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Cited By (34)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0908679A1 (en) * | 1997-10-10 | 1999-04-14 | Electrowatt Technology Innovation AG | Circuit for flame monitoring |
| WO1999019672A1 (en) * | 1997-10-10 | 1999-04-22 | Siemens Building Technologies Ag | Method and device for monitoring a flame |
| US6501383B1 (en) | 1997-10-10 | 2002-12-31 | Siemens Building Technologies Ag | Method and device for monitoring a flame |
| EP1719947A1 (en) | 2005-05-06 | 2006-11-08 | Siemens Building Technologies HVAC Products GmbH | Method and device for flame monitoring |
| US7382140B2 (en) | 2005-05-06 | 2008-06-03 | Siemens Building Technologies Hvac Products Gmbh | Method and device for flame monitoring |
| EP1983264A3 (en) * | 2007-04-16 | 2014-02-19 | Viessmann Werke GmbH & Co. KG | Flame monitoring device with voltage generator and voltage measuring device |
| DE102009057121A1 (en) | 2009-12-08 | 2011-06-09 | Scheer Heizsysteme & Produktionstechnik Gmbh | Method for qualitative monitoring of combustion status of boiler system in e.g. industrial combustion, involves determining exhaust gas value of combustion of fuel-air-mixture by boiler-isothermal current and/or voltage characteristic curve |
| US8947242B2 (en) | 2011-12-15 | 2015-02-03 | Honeywell International Inc. | Gas valve with valve leakage test |
| US9835265B2 (en) | 2011-12-15 | 2017-12-05 | Honeywell International Inc. | Valve with actuator diagnostics |
| US8905063B2 (en) | 2011-12-15 | 2014-12-09 | Honeywell International Inc. | Gas valve with fuel rate monitor |
| US10697632B2 (en) | 2011-12-15 | 2020-06-30 | Honeywell International Inc. | Gas valve with communication link |
| US9074770B2 (en) | 2011-12-15 | 2015-07-07 | Honeywell International Inc. | Gas valve with electronic valve proving system |
| US9995486B2 (en) | 2011-12-15 | 2018-06-12 | Honeywell International Inc. | Gas valve with high/low gas pressure detection |
| US9557059B2 (en) | 2011-12-15 | 2017-01-31 | Honeywell International Inc | Gas valve with communication link |
| US9851103B2 (en) | 2011-12-15 | 2017-12-26 | Honeywell International Inc. | Gas valve with overpressure diagnostics |
| US9846440B2 (en) | 2011-12-15 | 2017-12-19 | Honeywell International Inc. | Valve controller configured to estimate fuel comsumption |
| US8839815B2 (en) | 2011-12-15 | 2014-09-23 | Honeywell International Inc. | Gas valve with electronic cycle counter |
| US8899264B2 (en) | 2011-12-15 | 2014-12-02 | Honeywell International Inc. | Gas valve with electronic proof of closure system |
| US10851993B2 (en) | 2011-12-15 | 2020-12-01 | Honeywell International Inc. | Gas valve with overpressure diagnostics |
| US9657946B2 (en) | 2012-09-15 | 2017-05-23 | Honeywell International Inc. | Burner control system |
| US11421875B2 (en) | 2012-09-15 | 2022-08-23 | Honeywell International Inc. | Burner control system |
| US9234661B2 (en) | 2012-09-15 | 2016-01-12 | Honeywell International Inc. | Burner control system |
| US10422531B2 (en) | 2012-09-15 | 2019-09-24 | Honeywell International Inc. | System and approach for controlling a combustion chamber |
| US9683674B2 (en) | 2013-10-29 | 2017-06-20 | Honeywell Technologies Sarl | Regulating device |
| US10215291B2 (en) | 2013-10-29 | 2019-02-26 | Honeywell International Inc. | Regulating device |
| US10024439B2 (en) | 2013-12-16 | 2018-07-17 | Honeywell International Inc. | Valve over-travel mechanism |
| US9841122B2 (en) | 2014-09-09 | 2017-12-12 | Honeywell International Inc. | Gas valve with electronic valve proving system |
| US10203049B2 (en) | 2014-09-17 | 2019-02-12 | Honeywell International Inc. | Gas valve with electronic health monitoring |
| US9645584B2 (en) | 2014-09-17 | 2017-05-09 | Honeywell International Inc. | Gas valve with electronic health monitoring |
| US10503181B2 (en) | 2016-01-13 | 2019-12-10 | Honeywell International Inc. | Pressure regulator |
| US10564062B2 (en) | 2016-10-19 | 2020-02-18 | Honeywell International Inc. | Human-machine interface for gas valve |
| US11073281B2 (en) | 2017-12-29 | 2021-07-27 | Honeywell International Inc. | Closed-loop programming and control of a combustion appliance |
| US10697815B2 (en) | 2018-06-09 | 2020-06-30 | Honeywell International Inc. | System and methods for mitigating condensation in a sensor module |
| WO2023012019A1 (en) * | 2021-08-05 | 2023-02-09 | Truma Gerätetechnik GmbH & Co. KG | Burner having a controller and an ignition and ionisation electrode and method for monitoring and igniting the flame of a burner |
Also Published As
| Publication number | Publication date |
|---|---|
| DE4309454C2 (en) | 1997-03-06 |
| DE4309454A1 (en) | 1994-09-29 |
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