Combustion – Timer – programmer – retarder or condition responsive control – By combustion or combustion zone sensor
Reexamination Certificate
2001-05-01
2004-01-13
Basichas, Alfred (Department: 3743)
Combustion
Timer, programmer, retarder or condition responsive control
By combustion or combustion zone sensor
C431S025000, C340S579000
Reexamination Certificate
active
06676404
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns a measuring device for a flame. The invention also concerns a regulating device for a burner having the measuring device.
2. Description of the Prior Art
DE 19632 983 A1 discloses a measuring device for a flame and an associated regulating device in a gas burner, wherein a lambda reference value for low emissions is set by means of an ionization electrode. By means of a comparator, the analog signal is digitised for further processing. The signal produced by the comparator however involves only a slight signal variation and a small signal-noise spacing at the on-off threshold if the signal is also to be used for flame monitoring purposes.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a measuring device for a flame, which permits more accurate and improved signal evaluation.
In accordance with the invention, there is provided a measuring device for a flame, in particular for use in a regulating device for a burner, comprising an ionization electrode which is positionable in the flame region of the burner and to which an ac voltage is applied whereby a dc voltage component is superimposed in dependence on the ionization current, wherein the ac voltage component which is influenced by the flame resistance can be separated from the dc voltage component by way of first means and the separated ac voltage can be compared to the separated-off dc voltage component by way of second means in order to produce a pulse width-modulated signal.
An important concept of the invention is that the alternating component which is influenced by the flame signal can be separated from the dc voltage component by way of first means and the separated alternating component can be compared to the separated-off dc voltage component in order to produce a pulse width-modulated signal.
Fluctuations in the amplitude in the supply voltage are compensated by the comparison of the alternating component to the direct component as both components change in terms of amplitude in the same relationship. In contrast changes in the flame, for example due to changes in the air ratio, influence the two components unequally.
Further advantages are the signal variation which can be adjusted in a wide range, the high level of sensitivity and the large signal-noise spacing as to whether the flame is on or off, and the fact that the analog signal is highly accurate and reproducible.
Further advantageous aspects of the invention are set forth in the dependent claims.
Thus, signal transmission by way of an optocoupler is possible, in which case both items of information, flame on and off and PWM-signal, can be transmitted by way of just one optocoupler. The ionization electrode can be designed to be shock-proof by virtue of the installation of contact shock-protection resistors.
REFERENCES:
patent: 3627458 (1971-12-01), Wade
patent: 3726630 (1973-04-01), Potts
patent: 3766441 (1973-10-01), Gray
patent: 4088984 (1978-05-01), Muramoto et al.
patent: 4672324 (1987-06-01), van Kampen
patent: 4871307 (1989-10-01), Harris et al.
patent: 5472337 (1995-12-01), Guerra
patent: 5479086 (1995-12-01), Konstanzer
patent: 6356199 (2002-03-01), Niziolek et al.
patent: 4122636 (1993-01-01), None
patent: 4433425 (1996-03-01), None
patent: 19632983 (1998-02-01), None
patent: WO 99/19672 (1999-04-01), None
Basichas Alfred
Greer Burns & Crain Ltd.
Siemens Building Technologies AG
LandOfFree
Measuring device for a flame does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Measuring device for a flame, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Measuring device for a flame will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3198789