Combustion – Burner having electrical heater or igniter – Spark electrode in front of or adjacent fuel discharger
Reexamination Certificate
1996-05-23
2001-06-19
Lazarus, Ira S. (Department: 3743)
Combustion
Burner having electrical heater or igniter
Spark electrode in front of or adjacent fuel discharger
C431S043000, C431S072000, C361S263000
Reexamination Certificate
active
06247921
ABSTRACT:
TECHNICAL INFORMATION
This invention relates to spark generators, particularly those used in gas appliances to ignite a combustible gas. The invention also relates to the prevention of malfunctions in sensitive circuitry due to electromagnetic interference.
BACKGROUND OF THE INVENTION
Combustible gas is commonly ignited in gas appliances with a spark. For example, U.S. Pat. No. 4,865,539 (Geary) shows a circuit with a spark gap located in a combustion chamber into which combustible gas flows. A high voltage step up transformer has also been used to provide the operating voltage for the spark gap, and a spark gap has been used as a flame sensing mechanism. The two may be used in concert as shown in the Geary patent.
The spark generation equipment known in the art has a number of problems. Typically, a potential of 20-25 kilovolts (KV) is required to force a spark across the spark gap. This high voltage and the resulting spark generate electromagnetic interference (EMI) that sometimes causes nearby circuitry to malfunction. Recently, this problem has worsened because circuit designers are now using sensitive microcontrollers and microprocessors to implement circuit control functions in gas appliances.
Because designers commonly place circuit components in a compact area, for example, on a single printed circuit board, the high voltage step up transformer is typically located near sensitive components. Since the spark gap must be located near the gas supply, the spark gap is usually relatively far away from the other circuitry. This arrangement requires expensive high voltage wire to connect the spark gap to the remotely located control circuitry.
The high voltage wire must withstand approximately 20-25 KV to connect the step up transformer to the spark gap. Routing this high voltage wire away from sensitive components imposes design, layout, and construction constraints on the manufacturer. Furthermore, in the prior art, the spark gap and high voltage transformer are not a single unit. As a result, replacing the high voltage transformer is inconvenient and time consuming.
Accordingly, one object of the invention is to generate a spark without causing remote circuitry, including microcontrollers and microprocessors, to malfunction due to electromagnetic interference.
Another object of the invention is to reduce the need for expensive high voltage wire connecting the transformer to the spark electrodes in a spark generation apparatus.
Another object of the invention is to provide an apparatus for spark generation in which the spark electrodes and the high voltage transformer comprise a single easily replaceable module.
Still another object of the invention is to provide an apparatus for spark generation in which at least one of the spark electrodes may be used as a flame sensor.
Still another object of the invention is to provide an electronically controlled gas appliance containing an apparatus for spark generation which does not interfere with the electronic control circuitry of the appliance.
One or more of the preceding objects, or one or more other objects which will become plain upon consideration of the present specification, are satisfied by the invention described herein.
SUMMARY OF THE INVENTION
One aspect of the invention, which satisfies one or more of the above objects, is an apparatus for producing a spark. The apparatus includes a set of spaced electrodes forming a spark gap, a high voltage step up transformer in close proximity to and operatively connected to the electrodes, and a remote circuit, susceptible to malfunction due to electromagnetic interference, that is operatively associated with the apparatus.
A second aspect of the invention is a gas burning appliance having at least one gas burner, a set of electrodes spaced to form a spark gap adjacent to the gas burner, a high voltage step up transformer in close proximity and operatively connected to the electrodes, and a remote circuit, susceptible to malfunction due to electromagnetic interference, that is operatively associated with the appliance.
The present invention allows circuitry controlling a spark gap to operate without EMI induced malfunctions, and has other significant advantages such reducing cost by eliminating expensive high voltage wire and providing an easily replaceable spark gap and transformer module.
The present invention also allows the direct replacement of a hot ignitor assembly with a spark gap ignitor.
The present invention reduces EMI interference by directly connecting the electrodes to the transformer output, thus eliminating expensive high voltage wiring.
The present invention further provides a method of replacing a hot surface ignitor connected to a source of line voltage with a spark ignitor, comprising the steps of: removing the hot surface ignitor; leaving the connections to the source of line voltage; connecting a power supply to the source of the line voltage; connecting circuitry for generating pulses to the power supply; connecting a transformer to the pulse circuitry; and connecting an ignitor probe directly to the transformer.
REFERENCES:
patent: 3260299 (1966-07-01), Lister
patent: 3388362 (1968-06-01), Raffaelli
patent: 3536427 (1970-10-01), Potts
patent: 4073611 (1978-02-01), Kaduki et al.
patent: 4106889 (1978-08-01), Katchka
patent: 4111639 (1978-09-01), Matthews
patent: 4116613 (1978-09-01), Matthews
patent: 4140476 (1979-02-01), Kaplan
patent: 4231732 (1980-11-01), Newport et al.
patent: 4269589 (1981-05-01), Matthews
patent: 4483672 (1984-11-01), Wallace et al.
patent: 4565520 (1986-01-01), Gann
patent: 4865539 (1989-09-01), Geary
patent: 4885573 (1989-12-01), Fry et al.
patent: 4902222 (1990-02-01), Van Belle
patent: 4934925 (1990-06-01), Berlincourt
patent: 4955805 (1990-09-01), Ishiguro et al.
patent: 4959009 (1990-09-01), Hemsath
patent: 4971549 (1990-11-01), Geary
patent: 5044930 (1991-09-01), Hongo et al.
patent: 5060722 (1991-10-01), Zdenek et al.
patent: 5112218 (1992-05-01), Sigler
patent: 5123835 (1992-06-01), Richards et al.
patent: 5127823 (1992-07-01), Bonner
patent: 5409373 (1995-04-01), Phillips et al.
patent: 5550704 (1996-08-01), Morita et al.
American Standard International Inc.
Beres William J.
Ferguson Peter D.
Lazarus Ira S.
O'Driscoll William
LandOfFree
Apparatus for generating a spark does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for generating a spark, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for generating a spark will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2495814