EP1390668A1 - Flammenüberwachungsvorrichtung - Google Patents
FlammenüberwachungsvorrichtungInfo
- Publication number
- EP1390668A1 EP1390668A1 EP02727938A EP02727938A EP1390668A1 EP 1390668 A1 EP1390668 A1 EP 1390668A1 EP 02727938 A EP02727938 A EP 02727938A EP 02727938 A EP02727938 A EP 02727938A EP 1390668 A1 EP1390668 A1 EP 1390668A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- flame
- voltage
- monitoring device
- limiter
- sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
- F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
- F23N5/123—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electronic means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- 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
- F23N5/08—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N5/00—Systems for controlling combustion
- F23N5/26—Details
Definitions
- the present invention relates to a flame monitoring device according to the preamble of claim 1.
- a flame monitoring device in which an alternating voltage is supplied to a transformer and subsequently to a peak voltage limiter.
- the peak voltage limiter prevents the transmission of voltage peaks from the network to the working circuit.
- VDR Voltage-Dependent-Resistor
- VDR Voltage-Dependent-Resistor
- One problem with such flame monitoring devices is non-flame related rectification effects on the burner, e.g. with ionization electrodes due to chemical effects between the monitoring electrode and the reference ground.
- the present invention is based on the object of making flame monitoring devices of the type mentioned at the outset insensitive to non-flame-related rectification effects.
- Zener diodes If semiconductor components such as Zener diodes are used to generate an asymmetrical voltage, component errors of the Zener diode can also be controlled by the higher number of Zener diodes in one direction. If a Zener diode fails, sufficient diodes are still available for safe operation of the voltage limiter. The more additional Zener diodes that are used to create the asymmetry, the higher the errors that can be compensated for.
- Zener diodes shows no voltage dependency compared to varistors (with small series resistances) and it can also be temperature compensated by using Zener diodes with different temperature coefficients. If the (unwanted) property of the voltage dependence of varistors is to be simulated, this can be simulated by using higher-impedance series resistors in the Zener diode row.
- Zener diodes enables AC voltage stabilization with standard components, which can be obtained from several manufacturers.
- the implementation of AC voltage limitation using diodes also has the advantage that a voltage switchover, for example it may be necessary that the limited alternating voltage of an automatic burner control must be switched between two voltage values within a switching sequence, can be carried out in a simple manner by bridging some diodes of the diode path.
- the desired voltage swing can be freely selected by selecting the diodes.
- VDR voltage-dependent resistors
- Varistors and a switch or a varistor, a voltage source and a switch required for this are Varistors and a switch or a varistor, a voltage source and a switch required for this.
- Fig. 1 shows schematically a flame monitoring device
- 2B shows an equivalent circuit for a real flame
- 2C shows an equivalent circuit for a contaminated electrode
- 5B shows the course of the current i with a contaminated electrode and asymmetrical AC voltage
- 5C shows the profile of the current i with a contaminated electrode and symmetrical AC voltage.
- a flame monitoring device is shown schematically in FIG. is supplied with an input voltage U1 via the AC line voltage 1 and via a transformer 2.
- the behavior of the input voltage U1 is shown schematically in FIG. 4A.
- the input voltage U1 is limited to the limit voltage U2 via a resistor 3 and a voltage limiter 4, see FIG. 4B.
- a flame 6 can be generated by a burner 5.
- An ionization electrode 7 projects into the flame area of the flame 6.
- the alternating voltage U2 is applied to the burners 5 acting as electrodes and the ionization electrode 7.
- the flame 6 and the applied alternating voltage U2 produce a rectified ionization current.
- the AC voltage is filtered out by means of a low-pass filter consisting of a resistor 8 and a capacitor 9, and only the uniform portion which is used as the flame signal is passed on to an amplifier 10, in which the flame signal is amplified and passed on to a control device (not shown) for further processing.
- a UV sensor or any sensor that works on the rectifying effect of the flame amplifier signal can also be used. These sensors also show undesirable rectification effects under certain conditions, e.g. for mains voltages with DC voltage offset or certain sensor defects.
- Such sensors, as well as the ionization electrode shown in FIG. 1, can be described by the equivalent circuits in FIGS. 2A and 2B in order to explain the behavior.
- FIG. 2A shows the burner shown in FIG. 1 between points A and B with a flame and ionization electrode as an equivalent circuit for ideal behavior with a diode 21 and a resistor 20 in series. The same rectifying effect is generated by the diode as by the flame.
- FIG. 2B shows the burner shown in FIG. 1 between points A and B with flame and ionization electrode as an equivalent circuit for the real behavior with a diode 21 and a resistor 20 in series, to which a resistor 22 is connected in parallel.
- current flows not only in the forward direction of the diode 21, but also in the reverse direction of the diode.
- FIG. 2C shows the burner shown in FIG. 1 between points A and B with flame and ionization electrode as an equivalent circuit for the real behavior when the electrode is contaminated with a diode 21 and a resistor 20 in series, with a resistor 22 connected in parallel and a diode 23 and a resistor 24 is connected in parallel in series.
- FIG. 3 shows a voltage limiter according to the invention for generating an asymmetrical voltage consisting of diodes 31, which also conduct in the reverse direction from a certain voltage, for example so-called Zener diodes, additional Zener diodes 32 being arranged in one direction so that the voltage in the forward direction of the diode 21 compared to the voltage in the reverse direction is increased. This means that a higher current flows when there is a flame.
- the direction of installation of the voltage limiter results from points C and D, which correspond to points C and D in FIG. 1.
- the number of Zener diodes used depends on the application and must be designed specifically for each case. However, it is advantageous that the asymmetry takes place via two diodes, so that no flame simulation is obtained even if a second fault is to be assumed.
- the series resistors 33 shown are optional and serve to limit the surge current in the case of transient overvoltages.
- the diode path should preferably only be over diodes of the same type and value, i.e. the same breakdown voltage, to simplify the error analysis in the event of a possible short circuit of one (or more) diodes. It is also advantageous to use only diodes from the same manufacturer in order to further reduce the irregular probability of errors.
- a current i is measured across the resistor 8 in FIG. 1. If the circuit for the ideal behavior according to FIG. 2A is installed in the circuit according to FIG. 1, the behavior according to FIG. 5A results with i, with a maximum current i5. This can be explained by the diode 21, through which the negative half-wave is cut off in the reverse direction.
- the behavior according to FIG. 5B results, with a maximum current in the positive direction of i1 and in the negative direction of ⁇ ' 2 2B also follows that i1 is larger than i5 (i1> i5), since the resistor 22 is additionally connected in parallel. Through this resistor 22, however, a current can also flow in the negative half-wave, which has its maximum at i2, but is smaller in magnitude than i.
- voltage limiter 30 creates an asymmetrical behavior of limit voltage U2, as can be seen in FIG. 4B.
- FIG. 4C shows a symmetrical voltage U2 * , as is known from the prior art and which is measured at the same measuring points C and D as the voltage U2. If, as already explained above, the circuit for the real behavior according to FIG. 2B is built into the circuit according to FIG. 1, the behavior according to FIG. 5C results with a symmetrical behavior of the voltage U2 * known from the prior art, with a maximum current in the positive direction of i3 and in the negative direction of i4.
- i3 is smaller than i1 (i3 ⁇ i1), ie the ratio of i1 to i2 is greater than the ratio of i3 to ⁇ ' 4 ([ ⁇ ' 1 / ⁇ ' 2]> [i3 / ⁇ ' 4]).
- This better ratio for an asymmetrical voltage now allows the use of sensitive flame signal amplifiers, even if non-flame-related rectification effects have to be suppressed, which allows a better evaluation of the actual flame signal.
- the invention is not limited to the exemplary embodiments shown and described.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Measurement Of Current Or Voltage (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
- Control Of Combustion (AREA)
- Fire-Detection Mechanisms (AREA)
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10125574A DE10125574A1 (de) | 2001-05-25 | 2001-05-25 | Flammenüberwachungsvorrichtung |
DE10125574 | 2001-05-25 | ||
PCT/IB2002/001758 WO2002095295A1 (de) | 2001-05-25 | 2002-05-22 | Flammenüberwachungsvorrichtung |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1390668A1 true EP1390668A1 (de) | 2004-02-25 |
EP1390668B1 EP1390668B1 (de) | 2007-07-04 |
Family
ID=7686155
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP02727938A Expired - Lifetime EP1390668B1 (de) | 2001-05-25 | 2002-05-22 | Flammenüberwachungsvorrichtung |
Country Status (5)
Country | Link |
---|---|
US (1) | US7046154B2 (de) |
EP (1) | EP1390668B1 (de) |
AT (1) | ATE366395T1 (de) |
DE (2) | DE10125574A1 (de) |
WO (1) | WO2002095295A1 (de) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102005024763B3 (de) * | 2005-05-31 | 2006-06-08 | Stiebel Eltron Gmbh & Co. Kg | Heizgerät und Verfahren zum Steuern eines Heizgerätes |
EP2154430B1 (de) * | 2008-08-15 | 2015-09-30 | Siemens Aktiengesellschaft | Regeleinrichtung für einen Gasbrenner, sowie Verwendung einer solchen Regeleinrichtung |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1075317A (en) * | 1964-05-22 | 1967-07-12 | Danfoss As | Ac-operated switching circuit |
DE1230165B (de) * | 1964-08-07 | 1966-12-08 | Danfoss As | Wechselstromgespeister Flammenwaechter |
US3551908A (en) | 1967-12-26 | 1970-12-29 | Combustion Eng | Flame detector |
JPS59217417A (ja) * | 1983-05-25 | 1984-12-07 | Matsushita Electric Ind Co Ltd | 石油暖房器具 |
DE4122636C2 (de) * | 1991-07-09 | 1999-08-12 | Bosch Gmbh Robert | Vorrichtung und Verfahren zum Überwachen einer Flamme |
DE19605803A1 (de) * | 1996-02-16 | 1997-08-21 | Daug Deutsche Automobilgesells | Schaltungsanordnung zur Ionenstrommessung |
ES2158400T3 (es) * | 1996-05-09 | 2001-09-01 | Stiebel Eltron Gmbh & Co Kg | Procedimiento para el funcionamiento de un quemador de gas. |
DE19712373A1 (de) * | 1997-03-25 | 1998-10-01 | Bosch Gmbh Robert | Vorrichtung zum Überwachen eines Brenners |
DE19712938C1 (de) * | 1997-03-27 | 1998-05-14 | Honeywell Bv | Schaltungsanordnung zum Erzeugen einer Speisewechselspannung für den Flammenstab eines Flammenwächters |
-
2001
- 2001-05-25 DE DE10125574A patent/DE10125574A1/de not_active Withdrawn
-
2002
- 2002-05-22 AT AT02727938T patent/ATE366395T1/de not_active IP Right Cessation
- 2002-05-22 WO PCT/IB2002/001758 patent/WO2002095295A1/de active IP Right Grant
- 2002-05-22 US US10/477,005 patent/US7046154B2/en not_active Expired - Lifetime
- 2002-05-22 DE DE50210419T patent/DE50210419D1/de not_active Expired - Lifetime
- 2002-05-22 EP EP02727938A patent/EP1390668B1/de not_active Expired - Lifetime
Non-Patent Citations (1)
Title |
---|
See references of WO02095295A1 * |
Also Published As
Publication number | Publication date |
---|---|
US20040178915A1 (en) | 2004-09-16 |
DE50210419D1 (de) | 2007-08-16 |
EP1390668B1 (de) | 2007-07-04 |
US7046154B2 (en) | 2006-05-16 |
DE10125574A1 (de) | 2002-11-28 |
ATE366395T1 (de) | 2007-07-15 |
WO2002095295A1 (de) | 2002-11-28 |
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