Fuel gas ignition system for gas burners including devices and methods related thereto

Abstract

Featured is a gas burner ignition system using miniaturized hot surface igniters of various types configurations and material systems: The ignition system includes an electronic microprocessor which controls both the igniter operation and all functions of the ignition system.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application Ser. No. 60 / 225,891 filed Jul. 15, 2009, the teachings of which are incorporated herein by reference.FIELD OF INVENTION[0002]The present invention relates to control systems for fuel burner igniters and more particularly to control systems for electrical resistance-type igniters for fuel burners and methods for controlling the voltage thereto.BACKGROUND OF THE INVENTION[0003]There are a number of appliances such as cooking ranges and clothes dryers and heating apparatuses such as boilers and furnaces in which a combustible material, such as a combustible hydrocarbon (e.g., propane, natural gas, oil) is mixed with air (i.e., oxygen) and continuously combusted within the appliance or heating apparatus so as to provide a continuous source of heat energy. This continuous source of heat energy is used for example to cook food, heat water to supply a source of running hot water...

AI Technical Summary

Benefits of technology

[0013]The present invention features a fuel gas ignition system and methods for controlling fuel gas ignition. Such control systems and methods further control the energization of the igniter device.

[0015]Such an ignition system further includes a flame sensing means for continuously sensing presence of a burner flame such as by the flame rectification technique. In more particular embodiments, the flame rectification circuit design is established to eliminate the need for earthing or a ground, by the use of a comparator circuit actuated by a burner flame present between the igniter element and igniter assembly shielding.

[0018]After an igniter activation period of 1 to 4 seconds, the microcontroller causes power to be removed from the igniter and thereafter the microcontroller continuously monitors the burner flame. In the event burner flame is not detected, the microcontroller powers the igniter for the defined igniter activation period to attempt to light / re-light the burner. In further embodiments, the microcontroller is configured to make multiple trials or attempts for such ignition or lighting of the burner. In yet further embodiments, the microcontroller is configured to make N attempts, N being ≧1, to light / re-light the burner. The microcontroller also is operated so that there is near instantaneous shut down of the gas valve by the flame sensing circuit thereby essentially eliminating the possible flow of raw un-lit gas to the appliance.

[0019]The microcontroller also is configurable so as to include a soft lock-out so that the valve delivering the gas to the burner is turned off if the burner fails to light as determined by the flame sensing circuit and cannot be thereafter turned on without user intervention. In further embodiments, the microcontroller is configured so the user is required to re-set the valve operation. This allows the user to determine the cause for the burner failing to light or determine the need for service to the appliance.

[0028]In yet further embodiments, the microcontroller is configured to check the flame sensing signal at the end of burner operation. In the event that the microcontroller detects that a flame is still present after the end of a burning operation, potentially indicating that closure of the gas valve has failed to have properly occurred, the microcontroller is configured to reactivate the valve opening and closure sequence as an attempt to properly close the gas valve. A number of opening and closing sequences can be conducted as required. The microcontroller also is configurable to cause an auditory and / or a visual signal to be outputted or communicated to the user to identify the faulted condition. In this way, an indication is provided to the user to allow them to determine the reason for the fault, to correct the fault and / or to have appliance serviced.

Problems solved by technology

Problems with spark-type igniters, however, include among other things the electronic and physical noise produced by the spark.

Known ignition modules for gas-fired burners, however, are susceptible to malfunctions in use.

In addition, the modules are often sensitive to voltage on the neutral conductor which desensitizes the flame detection circuit and can lead to continuously generated sparks despite the presence of a flame on a burner.

If the electrical junction box is not properly wired, the ignition module will continuously spark.

Unnecessary sparking of the ignition module reduces energy efficiency and also shortens a useable life of the ignition module.

Hot surface-type igniters, however, can require significant ignition / warm-up time to resistively heat the resistance igniter sufficiently to a temperature that will ignite the fuel-air mixture (e.g., gas-air).

In addition to wasting fuel, if an ignition source is inadvertently put in proximity to the burner, the unlit gas would be ignited.

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